ZBIO

- Obexelimab BLA submission for the treatment of IgG4-RD accepted by FDA; PDUFA target action date of May 27, 2027 - - New study data confirm bioequivalence of obexelimab single-dose prefilled autoinjector pen compared to prefilled syringes - - Obexelimab global Phase 2 SunStone SLE trial topline results expected in Q4 2026 - - ZB021 (oral IL-17AA/AF inhibitor) dosing ongoing in Phase 1 trial; initial clinical data expected by year-end - - Four Orelabrutinib abstracts accepted for poster presentation at MSToronto 2026 - - Expanded Board of Directors with the appointment of Christy Oliger, who brings more than 30 years of global biopharmaceutical commercial and operating experience - - CFO to transition to Strategic Advisor to the Board Chair at the end of September - - Cash, cash equivalents and investments of $673.9 million as of June 30, 2026 - WALTHAM, Mass., Aug. 13, 2026 (GLOBE NEWSWIRE) -- Zenas BioPharma, Inc. (“Zenas” or the “Company”) (Nasdaq: ZBIO), a clinical-stage global biopharmaceutical company advancing therapies for patients living with autoimmune and inflammatory diseases, today reported financial results for the quarter ended June 30, 2026, and provided recent corporate updates. "2026 continues to be a transformative year for Zenas, highlighted by FDA acceptance of the obexelimab BLA for the treatment of IgG4-RD, with a PDUFA date of May 27, 2027. Our expanding team is actively preparing for the potential commercialization of our first product," said Lonnie Moulder, Founder and Chief Executive Officer of Zenas. "The strength of the Phase 3 INDIGO data for obexelimab in IgG4-RD was underscored by its selection as an oral presentation at EULAR and simultaneous publication in the New England Journal of Medicine. Beyond IgG4-RD, we are on track to report Phase 2 topline data for obexelimab in SLE and initial Phase 1 data for ZB021 by year-end. We continue to execute across our portfolio and make meaningful progress toward our vision of becoming a fully integrated, global development and commercial-stage biopharmaceutical company that brings impactful treatments to patients living with autoimmune and chronic inflammatory diseases." Corporate highlights Obexelimab, a CD19 and FcγRIIb inhibitor of B cell function In August, the U.S. Food and Drug Administration (FDA) accepted the Company’s Biologics License Application (BLA) for obexelimab for the treatment of Immunoglobulin G4-Related Disease (IgG4-RD): The BLA has a Prescription Drug User Fee Act (PDUFA) target action date of May 27, 2027. Zenas expects to submit a Marketing Authorization Application (MAA) to the European Medicines Agency (EMA) in the second half of 2026. Positive results from the Phase 3 INDIGO registrational trial of obexelimab for the treatment of IgG4-RD presented at EULAR and published in NEJM in June 2026: Additional data from the INDIGO trial presented at the European Alliance of Associations for Rheumatology (EULAR) 2026 Congress, and published online by the New England Journal of Medicine. Obexelimab met the primary endpoint, demonstrating a highly statistically significant and clinically meaningful 56% (HR 0.44; 95% CI 0.277–0.711; p=0.0005) reduction in the risk of IgG4-RD flare compared to placebo during the 52-week randomized placebo-controlled period. A majority of patients treated with obexelimab (73.2%) remained flare-free through Week 52, compared to fewer than half (45.4%) of placebo-treated patients. Obexelimab met and demonstrated highly statistically significant activity compared to placebo on all four key secondary endpoints and significantly lowered the total amount of glucocorticoid use and reduced glucocorticoid-related toxicities. Obexelimab was well tolerated, treatment-emergent adverse events (TEAEs) were similar between obexelimab and placebo-treated patients, and the incidence of Grade ≥3 TEAEs and infections were lower with obexelimab compared to placebo. More information on the Phase 3 INDIGO trial (NCT05662241) is available at clinicaltrials.gov. In August, our partner Bristol Myers Squibb announced they submitted a marketing authorization application to Japan's Pharmaceuticals and Medical Devices Agency (PMDA) for obexelimab for the treatment of IgG4-RD: The application is based on the results of the global Phase 3 INDIGO trial. BMS hold exclusive rights to develop, manufacture and commercialize obexelimab in Japan, South Korea, Taiwan, Singapore, Hong Kong and Australia. Bioequivalence established for obexelimab delivered via prefilled syringe versus prefilled pen: New clinical study data confirm bioequivalence between obexelimab delivered via prefilled syringe and single-dose prefilled pen. The single-dose prefilled pen has the potential to offer a more convenient delivery option for patients. Zenas intends to submit a supplemental application to obexelimab's IgG4-RD BLA, if approved, and to include the single-dose prefilled pen and bioequivalence data in a European MAA submission in the second half of 2026. Phase 2 SunStone trial in Systemic Lupus Erythematosus (SLE) topline results expected in 4Q 2026: Zenas anticipates reporting topline overall and biomarker population results in the fourth quarter of 2026. More information on the Phase 2 SunStone trial (NCT06559163) is available at clinicaltrials.gov. ZB021, a novel oral, IL-17AA/AF inhibitor that blocks IL-17 AA homodimer and IL-17AF heterodimer signaling Dosing ongoing in Phase 1 trial of ZB021 in healthy volunteers: Dosing is ongoing in the single ascending dose (SAD) and now, the multiple ascending dose (MAD) parts of the Phase 1 trial designed to evaluate the safety, tolerability, and pharmacokinetic profile of ZB021 in healthy volunteers. The trial is being conducted in partnership with InnoCare Pharma in China. These data are expected by year-end 2026. Upon completion and evaluation of the SAD and MAD study, Zenas plans to initiate a proof-of-concept (POC) trial in North America to evaluate clinical activity and safety in psoriasis patients with results anticipated in 2027. Orelabrutinib, a highly selective CNS-penetrant Bruton’s Tyrosine Kinase (BTK) inhibitor Orelabrutinib Phase 3 PriMroSe Primary Progressive Multiple Sclerosis (PPMS) trial ongoing: PriMroSe, a Phase 3, global registration-directed, multicenter, randomized, double-blind, placebo-controlled trial to evaluate the efficacy and safety of orelabrutinib in patients with PPMS is ongoing. More information on the Phase 3 PriMroSe trial (NCT07067463) is available at clinicaltrials.gov. Orelabrutinib Phase 3 Monarch non-active Secondary Progressive Multiple Sclerosis (naSPMS) trial ongoing: Monarch, a Phase 3, global registration-directed, multicenter, randomized, double-blind, placebo-controlled trial to evaluate the efficacy and safety of orelabrutinib in patients with naSPMS is ongoing. More information on the Phase 3 Monarch trial (NCT07299019) is available at clinicaltrials.gov. Four abstracts accepted for MSToronto 2026 including 24-week data and pharmacokinetic analysis from the orelabrutinib Phase 2 relapsing remitting multiple sclerosis trial along with study designs for the Phase 3 Monarch and PriMroSe trials: Zenas to host industry-supported symposium at MSToronto 2026: Symposium entitled “BTK Inhibition in MS: An Emerging Therapeutic Approach to Disability Progression” to be chaired and moderated by Amit Bar-Or, MD, FRCP, FAAN, FANA Chief of the Multiple Sclerosis Division, Department of Neurology, Perelman School of Medicine at the University of Pennsylvania. Early development programs ZB022, an oral, brain-penetrant, TYK2-JH2 inhibitor ZB014, a half-life extended, anti-CD19 and FcγRIIb monoclonal antibody (mAb) Board of Directors Appointment In August 2026, Zenas appointed Christy Oliger to its Board of Directors. Ms. Oliger brings more than 30 years of commercial and operating experience across global biopharmaceutical organizations, including as Senior Vice President and Business Unit Head, Oncology at Genentech, where she led a portfolio of 15 products representing more than $13 billion in U.S. revenue, and as Senior Vice President and Business Unit Head, Neurology, Rare Disease and Infectious Disease, where she led the teams behind launches in multiple sclerosis, hemophilia and spinal muscular atrophy. She currently serves on the boards of directors of Bicara Therapeutics, Vera Therapeutics, Karyopharm Therapeutics and Replimune Inc., and previously served as a director of Nuvalent Inc., Sierra Oncology, Reata Pharmaceuticals, RayzeBio and LAVA Therapeutics. She began her career in life sciences at Schering-Plough and holds a B.A. in economics from the University of California, Santa Barbara."We are pleased to welcome Christy to our Board of Directors as Zenas advances toward becoming a commercial-stage company," said Lonnie Moulder, Chief Executive Officer of Zenas BioPharma. "Christy has spent her career building the organizations and capabilities that bring important new medicines to patients and leading the business units behind multiple successful launches. She has since served as a director of numerous public late-stage clinical- and commercial-stage biotechnology companies. Her experience complements our board as we work to deliver potentially transformative therapies to patients with autoimmune and chronic inflammatory diseases." Leadership Transition The Company announced that Jennifer Fox will transition from her current role as Chief Financial Officer and Chief Business Officer to serve in a new role as Strategic Advisor to the Board Chair effective September 30th. Joe Farmer, President and COO, will serve as Principal Financial Officer and Principal Accounting Officer until the appointment of a Chief Financial Officer.“I would like to thank Jennifer Fox, who has played an instrumental role in the development and execution of our growth strategy over the past several years, as we successfully executed several substantial capital raising transactions and significantly expanded our R&D pipeline. I look forward to her future contributions and working with her as a strategic advisor,” said Lonnie Moulder, Chief Executive Officer of Zenas BioPharma. Second quarter 2026 financial results As of June 30, 2026, the Company’s cash, cash equivalents and investments were $673.9 million including $43.2 million aggregate net proceeds in April 2026 from the underwriters’ exercise in full of their over-allotment option for the convertible notes and option to purchase additional shares of common stock from the March 2026 concurrent public offerings. The Company expects that its cash, cash equivalents and investments, as of June 30, 2026, together with the net proceeds of $48.7 million received to date in the third quarter of 2026 from sales under its ATM facility, and assuming receipt of the potential $75 million milestone from Royalty Pharma and $75 million drawn from the debt facility with Pharmakon associated with achieving FDA marketing approval of obexelimab for IgG4-RD, its cash, cash equivalents and investments will fund its operating expenses and capital expenditure requirements at least through the second quarter of 2029. Revenue was $1.0 million for the quarter ended June 30, 2026, related to the achievement of a development milestone pursuant to the Company’s agreement with Tenacia Biotechnology (Hong Kong) Co., Limited associated with ZB005, which were originally licensed from Dianthus Therapeutics. The Company did not recognize revenue for the quarter ended June 30, 2025. Research and development (R&D) expenses were $62.9 million for the quarter ended June 30, 2026, compared to $43.0 million for the quarter ended June 30, 2025. The increase of $19.9 million in R&D expenses was primarily due to an increase in costs related to clinical trial and regulatory costs and an increase in personnel costs including stock-based compensation expense primarily due to an increase in headcount. General and administrative (G&A) expenses were $15.7 million for the quarter ended June 30, 2026, compared to $12.1 million for the quarter ended June 30, 2025. The increase of $3.6 million in G&A expenses was primarily due to an increase in personnel costs, including stock-based compensation expense primarily due to an increase in headcount associated with pre-commercialization activities and other expenses primarily attributable to company growth and continued operations as a public company. Acquired in-process research and development (AIPR&D) expenses were $30.0 million for the quarter ended June 30, 2026, which related to the achievement of a milestone under the Xencor Agreement for the completion of the FDA marketing authorization submission, and for the achievement of one of the near-term regulatory milestones under the InnoCare Agreement. The Company did not recognize AIPR&D expense for the quarter ended June 30, 2025. Other income (expense), net was $3.7 million of expense for the quarter ended June 30, 2026, compared to $3.0 million of income for the quarter ended June 30, 2025. The change of $6.6 million is primarily related to an increase in interest expense related to our royalty obligation, senior secured term loan and convertible senior notes, partially offset by interest income related to higher cash, cash equivalents and investments balances. Net loss was $111.5 million for the quarter ended June 30, 2026, compared to a net loss of $52.2 million for the quarter ended June 30, 2025. About ObexelimabObexelimab is a bifunctional monoclonal antibody designed to bind both CD19 and FcγRIIb, which are broadly present across B cell lineage, to inhibit the activity of cells that are implicated in many autoimmune diseases without depleting them. This unique inhibitory mechanism of action and self-administered, subcutaneous injection regimen may broadly and effectively address the pathogenic role of the B cell lineage in chronic autoimmune disease. Obexelimab has been evaluated in eight clinical trials in a total of 383 subjects, including INDIGO. Obexelimab was well tolerated and demonstrated clinical activity across these clinical trials. Zenas expects to report topline results from a Phase 2 trial for obexelimab in systemic lupus erythematosus in the fourth quarter of 2026. About ZB021ZB021 is a novel potentially best-in-class oral small molecule IL-17AA/AF inhibitor being developed by Zenas BioPharma in partnership with InnoCare Pharma. ZB021 is designed to selectively block the signal transduction pathways of both the IL-17AA homodimer and IL-17AF heterodimer, inhibiting downstream pro-inflammatory cytokine and chemokine release. Preclinical studies have demonstrated potent anti-inflammatory activity, a favorable safety profile, and excellent Absorption, Distribution, Metabolism, and Excretion (ADME) properties. The IL-17 pathway has demonstrated broad utility across many rheumatic and dermatologic indications. Currently, no oral IL-17 inhibitors have been approved or are in late-stage development globally. ZB021's oral, small molecule profile may offer meaningful advantages over currently approved biologic IL-17 therapies in terms of convenience, compliance, and accessibility. Zenas licensed the exclusive rights from InnoCare Pharma to develop, manufacture, and commercialize ZB021 in all fields of use worldwide, excluding greater China and Southeast Asia. About OrelabrutinibOrelabrutinib is a late-stage, potentially best-in-class, highly selective central nervous system (CNS)-penetrant, oral, small molecule Bruton’s Tyrosine Kinase (BTK) inhibitor. Orelabrutinib’s mechanism of action targets pathogenic B cells in both the periphery and the CNS. Additionally, it directly modulates macrophages and microglial cells in the CNS, with the potential to address compartmentalized inflammation and disease progression in multiple sclerosis (MS). In MS, Zenas is advancing PriMroSe, a Phase 3 trial in Primary Progressive MS (PPMS), and Monarch, a Phase 3 trial in non-active Secondary Progressive MS (naSPMS). Orelabrutinib is approved for B cell malignancies in mainland China and Singapore, marketed by our partner InnoCare. About Zenas BioPharmaZenas is a clinical-stage global biopharmaceutical company focused on the development and commercialization of therapies for autoimmune diseases and inflammatory conditions. Zenas combines our experienced leadership team with a disciplined global product candidate acquisition approach to identify, acquire and develop product candidates with the potential to deliver clinically meaningful benefits to patients. Zenas is advancing two late-stage, potential franchise molecules, obexelimab and orelabrutinib. Obexelimab, Zenas’ lead product candidate, is a bifunctional monoclonal antibody designed to bind CD19 and FcγRIIb to inhibit the activity of B cells implicated in many autoimmune diseases without depleting them. Zenas believes that the unique mechanism of action of obexelimab and its self-administered, subcutaneous injection regimen may enable sustained control across multiple chronic autoimmune diseases. Orelabrutinib is a potentially best-in-class, highly selective CNS-penetrant, oral, small molecule BTK inhibitor. Orelabrutinib’s mechanism of action targets pathogenic B cells not only in the periphery but also within the CNS. Additionally, it directly modulates macrophages and microglial cells in the CNS, with the potential to address compartmentalized inflammation and disease progression in MS. Zenas’ earlier stage programs include ZB021, a novel, potentially best-in-class, oral, IL-17AA/AF inhibitor, ZB022, a preclinical, potentially best-in-class, oral, brain-penetrant, TYK2 inhibitor, and ZB014, a preclinical, half-life extended anti-CD19 and FcγRIIb monoclonal antibody. For more information about Zenas BioPharma, please visit https://zenasbio.com/ and follow us on LinkedIn. Zenas BioPharma Forward-Looking StatementsThis press release contains “forward-looking statements” which involve risks, uncertainties and contingencies, many of which are beyond the control of the Company, which may cause actual results, performance, or achievements to differ materially from anticipated results, performance, or achievements. All statements other than statements of historical facts contained in this press release are forward-looking statements. In some cases, forward-looking statements can be identified by terms such as “may,” “will,” “should,” “expect,” “plan,” “anticipate,” “could,” “intend,” “target,” “project,” “contemplate,” “believe,” “estimate,” “predict,” “potential” or “continue” or the negative of these terms or other similar expressions, although not all forward-looking statements contain these words. Forward looking statements include, but are not limited to, statements regarding the Company’s product candidates, including the timing, progress and results of preclinical studies and clinical trials, including the timing of reporting the topline results from the SunStone trial and the ZB021 SAD and MAD study; the timing of regulatory submissions, including timing of our submission of a MAA to the EMA for obexelimab in IgG4-RD; subject to ZB021 SAD and MAD study results, the initiation of a POC trial of ZB021; the potential for ZB021 to provide meaningful advantages over currently approved biologics; subject to IND studies and clearance, the initiation of Phase 1 clinical studies of ZB014 and ZB022; the potential for ZB014 to provide the clinical activity and safety profile observed with obexelimab while offering a once-monthly dosing schedule; our ability to draw down on the Pharmakon debt facility; receipt of additional funding under our Royalty Pharma and Pharmakon agreements contingent upon FDA approval of obexelimab; the potential approval and commercialization of obexelimab; our readiness for commercialization; and the Company’s cash guidance. The forward-looking statements in this press release speak only as of the date of this press release and are subject to a number of known and unknown risks, uncertainties and assumptions that could cause the Company’s actual results to differ materially from those anticipated in the forward-looking statements, including, but not limited to: the Company’s limited operating history, incurrence of substantial losses since the Company’s inception and anticipation of incurring substantial and increasing losses for the foreseeable future; the Company’s need for substantial additional financing to achieve the Company’s goals; the uncertainty of clinical development, which is lengthy and expensive, and characterized by uncertain outcomes, and risks related to additional costs or delays in completing, or failing to complete, the development and commercialization of the Company’s current product candidates or any future product candidates; delays or difficulties in the enrollment and dosing of patients in clinical trials; the impact of any significant adverse events or undesirable side effects caused by the Company’s product candidates; potential competition, including from large and specialty pharmaceutical and biotechnology companies, many of which already have approved therapies in the Company’s current indications; the Company’s ability to realize the benefits of the Company’s current or future collaborations or licensing arrangements and ability to successfully consummate future partnerships; the Company’s ability to obtain regulatory approval to commercialize any product candidate in the United States or any other jurisdiction; the risk that the data from our clinical trials is not sufficient to the satisfaction of the FDA or comparable foreign regulatory authorities to support the submission of a biologics license application or other comparable submission or to obtain regulatory approval for our product candidates for which we seek approval in the U.S. or elsewhere, and the risk that any such approval may be for a more narrow indication than the Company seeks; the Company’s dependence on the services of the Company’s senior management and other clinical and scientific personnel, and the Company’s ability to retain these individuals or recruit additional management or clinical and scientific personnel; the Company’s ability to grow the Company’s organization, and manage the Company’s growth and expansion of the Company’s operations; risks related to the manufacturing of the Company’s product candidates, which is complex, and the risk that the Company’s third-party manufacturers may encounter difficulties in production; the Company’s ability to obtain and maintain sufficient intellectual property protection for the Company’s product candidates or any future product candidates the Company may develop; the Company’s reliance on third parties to conduct the Company’s preclinical studies and clinical trials; the Company’s compliance with the Company’s obligations under the licenses granted to the Company by others, for the rights to develop and commercialize the Company’s product candidates; significant political, trade, and regulatory developments, including changes in relations between the U.S. and China; risks related to the operations of the Company’s suppliers, many of which are located outside of the United States, including the Company’s current sole contract manufacturing organization for obexelimab drug substance and drug product, WuXi Biologics (Hong Kong) Limited, and our partner, InnoCare, both of which are located in China; the risk that the Company’s indebtedness resulting from the Company’s loan agreement with Pharmakon Advisors LP, and the guarantors party to such agreement, or future indebtedness could adversely affect the Company’s financial condition or restrict the Company’s future operations; and other risks and uncertainties described in the section “Risk Factors” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2025, and Quarterly Report on Form 10-Q for the quarter ended June 30, 2026, as well as other information we file with the Securities and Exchange Commission. The forward-looking statements in this press release are inherently uncertain, speak only as of the date of this press release and may prove incorrect. These statements are based upon information available to the Company as of the date of this press release and while the Company believes such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that the Company has conducted an exhaustive inquiry into, or review of, all potentially available relevant information. Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified and some of which are beyond the Company’s control, these forward-looking statements should not be relied upon as guarantees of future events. The events and circumstances reflected in the forward-looking statements may not be achieved or occur and actual future results, levels of activity, performance and events and circumstances could differ materially from those projected in the forward-looking statements. Moreover, the Company operates in an evolving environment. New risks and uncertainties may emerge from time to time, and management cannot predict all risks and uncertainties. Except as required by applicable law, the Company does not undertake to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events, changed circumstances or otherwise. The Zenas BioPharma word mark, logo mark, and the “lightning bolt” design are trademarks of Zenas BioPharma, Inc. or its affiliated companies. All rights reserved. Contacts: Investors:Argot [email protected] Media:Kristin AinsworthSVP, U.S. Commercial Strategy & Corporate Affairs612.839.6748

- Safety and efficacy results from the Phase 3 INDIGO trial to be presented by Emanuel Della Torre, M.D., Ph.D., on Thursday June 4, 2026, at 2:45 PM GMT - WALTHAM, Mass., May 19, 2026 (GLOBE NEWSWIRE) -- Zenas BioPharma, Inc. (“Zenas,” “Zenas BioPharma” or the “Company”) (Nasdaq: ZBIO), a clinical-stage global biopharmaceutical company committed to being a leader in the development and commercialization of transformative therapies for patients living with autoimmune diseases, today announced that safety and efficacy outcomes from the Phase 3 INDIGO trial evaluating obexelimab in Immunoglobulin G4-Related Disease (IgG4-RD) will be presented in an oral presentation at the upcoming European Alliance of Associations for Rheumatology (EULAR) 2026 Congress, held from June 3-6, 2026, in London, England. INDIGO, the largest randomized, double-blind, placebo-controlled study conducted in IgG4-RD, met the primary endpoint demonstrating a highly statistically significant and clinically meaningful 56% reduction in the risk of IgG4-RD flare compared to placebo (HR 0.443; 95% CI 0.277–0.711; p=0.0005) during the 52-week randomized placebo-controlled period. Obexelimab also met and demonstrated highly statistically significant activity compared to placebo on all four key secondary endpoints: time to first investigator-determined flare requiring rescue therapy (p=0.0001), number of investigator- and AC-determined flares requiring rescue therapy (p=0.0008), proportion of patients achieving complete remission (p=0.0049), and cumulative glucocorticoid rescue therapy use (p=0.0042). Obexelimab was well tolerated with no new safety signals observed. Treatment-emergent adverse events (TEAEs) occurred in 97.9% vs 95.9% of participants (obexelimab vs placebo). Incidence of Grade ≥3 TEAEs was less with obexelimab (11.3% vs 23.7%), and the incidence of serious adverse events was 10.3% vs 18.6%. Infections occurred in 53.6% vs 62.9% of participants. Injection-site reactions were reported in 3.5% vs 2.3% of total patient doses. Hypersensitivity occurred in 16.5% vs 11.3% of participants. There were no deaths in the obexelimab group and one death (1.0%) in the placebo group. Details of EULAR Presentation: Title: Obexelimab, a B Cell Inhibitor, in IgG4-Related Disease: Results From the Phase 3 INDIGO Trial Presenting Author: Emanuel Della Torre, M.D., Ph.D., Associate Professor of Rheumatology, Vita-Salute San Raffaele University, Milan, Italy Session: New Perspectives in IgG4-Associated Diseases Session Date & Time: Thursday, June 4, 2026, at 2:45 PM GMT Abstract Number: OP018 Location: Excel London, Room N1 About ObexelimabObexelimab is a bifunctional monoclonal antibody designed to bind both CD19 and FcgRIIb, which are broadly present across B cell lineage, to inhibit the activity of cells that are implicated in many autoimmune diseases without depleting them. This unique inhibitory mechanism of action and self-administered, subcutaneous injection regimen may broadly and effectively address the pathogenic role of the B cell lineage in chronic autoimmune disease. Obexelimab has been evaluated in eight clinical trials in a total of 383 subjects, including INDIGO. Obexelimab was well tolerated and demonstrated clinical activity across these clinical trials. The registrational Phase 3 INDIGO trial for Immunoglobulin G4-Related Disease met its primary endpoint and all four key secondary endpoints with high statistical significance. The trial continues to evaluate patients in the 3-year open label extension period which will further build upon the largest body of clinical data reported for IgG4-RD patients to date. Enrollment in a randomized Phase 2 trial for Systemic Lupus Erythematosus is completed and Zenas expects to report topline results, including biomarker data from this trial in the fourth quarter of 2026. About Zenas BioPharmaZenas is a clinical-stage global biopharmaceutical company committed to becoming a leader in the development and commercialization of transformative therapies for patients living with autoimmune diseases. Zenas’ core business strategy combines our experienced leadership team with a disciplined product candidate acquisition approach to identify, acquire and develop product candidates globally that we believe can provide superior clinical benefits to patients living with autoimmune diseases. Zenas is advancing two late-stage, potential franchise molecules, obexelimab and orelabrutinib. Obexelimab, Zenas’ lead product candidate, is a bifunctional monoclonal antibody designed to bind both CD19 and FcgRIIb, which are broadly present across B cell lineage, to inhibit the activity of cells that are implicated in many autoimmune diseases without depleting them. Zenas believes that obexelimab’s unique mechanism of action and self-administered, subcutaneous injection regimen may broadly and effectively address the pathogenic role of B cell lineage in chronic autoimmune disease. Orelabrutinib is a potentially best-in-class, highly selective CNS-penetrant, oral, small molecule BTK inhibitor. Orelabrutinib’s mechanism of action targets pathogenic B cells not only in the periphery but also within the CNS. Additionally, it directly modulates macrophages and microglial cells in the CNS, with the potential to address compartmentalized inflammation and disease progression in MS. Zenas’ earlier stage programs include ZB021, a novel, potentially best-in-class, oral small molecule IL-17AA/AF inhibitor, ZB022, a preclinical, potentially best-in-class, oral, brain-penetrant, TYK2 inhibitor, and ZB014, a preclinical, half-life extended anti-CD19 and FcgRIIb monoclonal antibody. For more information about Zenas BioPharma, please visit https://zenasbio.com/ and follow us on LinkedIn. Zenas BioPharma Forward-Looking StatementsThis press release contains “forward-looking statements” which involve risks, uncertainties and contingencies, many of which are beyond the control of the Company, which may cause actual results, performance, or achievements to differ materially from anticipated results, performance, or achievements. All statements other than statements of historical facts contained in this press release are forward-looking statements. In some cases, forward-looking statements can be identified by terms such as “may,” “will,” “should,” “expect,” “plan,” “anticipate,” “could,” “intend,” “target,” “project,” “contemplate,” “believe,” “estimate,” “predict,” “potential” or “continue” or the negative of these terms or other similar expressions, although not all forward-looking statements contain these words. Forward looking statements include, but are not limited to, statements concerning Zenas’s milestones, expectations and intentions, including the potential for obexelimab to address the pathogenic role of B cell lineage in chronic autoimmune disease; the timing of results and data from clinical trials, including the timing of reporting the topline results from the SunStone trial; and the potential for orelabrutinib to address compartmentalized inflammation and disease progression in MS. The forward-looking statements in this press release speak only as of the date of this press release and are subject to a number of known and unknown risks, uncertainties and assumptions that could cause the Company’s actual results to differ materially from those anticipated in the forward-looking statements, including, but not limited to: the Company’s limited operating history, incurrence of substantial losses since the Company’s inception and anticipation of incurring substantial and increasing losses for the foreseeable future; the Company’s need for substantial additional financing to achieve the Company’s goals; the uncertainty of clinical development, which is lengthy and expensive, and characterized by uncertain outcomes, and risks related to additional costs or delays in completing, or failing to complete, the development and commercialization of the Company’s current product candidates or any future product candidates; delays or difficulties in the enrollment and dosing of patients in clinical trials; the impact of any significant adverse events or undesirable side effects caused by the Company’s product candidates; potential competition, including from large and specialty pharmaceutical and biotechnology companies, many of which already have approved therapies in the Company’s current indications; the Company’s ability to realize the benefits of the Company’s current or future collaborations or licensing arrangements and ability to successfully consummate future partnerships; the Company’s ability to obtain regulatory approval to commercialize any product candidate in the United States or any other jurisdiction, the risk that the data from our clinical trials is not sufficient to the satisfaction of the FDA or comparable foreign regulatory authorities to support the submission of a biologics license application or other comparable submission or to obtain regulatory approval for our product candidates for which we seek approval in the U.S. or elsewhere, and the risk that any such approval may be for a more narrow indication than the Company seeks; the Company’s dependence on the services of the Company’s senior management and other clinical and scientific personnel, and the Company’s ability to retain these individuals or recruit additional management or clinical and scientific personnel; the Company’s ability to grow the Company’s organization, and manage the Company’s growth and expansion of the Company’s operations; risks related to the manufacturing of the Company’s product candidates, which is complex, and the risk that the Company’s third-party manufacturers may encounter difficulties in production; the Company’s ability to obtain and maintain sufficient intellectual property protection for the Company’s product candidates or any future product candidates the Company may develop; the Company’s reliance on third parties to conduct the Company’s preclinical studies and clinical trials; the Company’s compliance with the Company’s obligations under the licenses granted to the Company by others, for the rights to develop and commercialize the Company’s product candidates; significant political, trade, regulatory developments, including changes in relations between the U.S. and China; risks related to the operations of the Company’s suppliers, many of which are located outside of the United States, including the Company’s current sole contract manufacturing organization for obexelimab drug substance and drug product, WuXi Biologics (Hong Kong) Limited, and our partner, InnoCare, both of which are located in China; the risk that the Company’s indebtedness resulting from the Company’s loan agreement with Pharmakon Advisors LP, and the guarantors party to such agreement, or future indebtedness could adversely affect the Company’s financial condition or restrict the Company’s future operations; and other risks and uncertainties described in the section “Risk Factors” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2025 and Quarterly Report on Form 10-Q for the first quarter ended March 31, 2026, as well as other information we file with the Securities and Exchange Commission. The forward-looking statements in this press release are inherently uncertain, speak only as of the date of this press release and may prove incorrect. These statements are based upon information available to the Company as of the date of this press release and while the Company believes such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that the Company has conducted an exhaustive inquiry into, or review of, all potentially available relevant information. Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified and some of which are beyond the Company’s control, these forward-looking statements should not be relied upon as guarantees of future events. The events and circumstances reflected in the forward-looking statements may not be achieved or occur and actual future results, levels of activity, performance and events and circumstances could differ materially from those projected in the forward-looking statements. Moreover, the Company operates in an evolving environment. New risks and uncertainties may emerge from time to time, and management cannot predict all risks and uncertainties. Except as required by applicable law, neither we, nor our affiliates, advisors or representatives, undertake any obligation to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events, changed circumstances or otherwise. The Zenas BioPharma word mark, logo mark, and the “lightning bolt” design are trademarks of Zenas BioPharma, Inc. or its affiliated companies. Investor and Media Contact:Argot [email protected]

– Obexelimab marketing applications for the treatment of IgG4-RD on-target for submission to the FDA this quarter and the EMA in H2 2026 based on the Phase 3 INDIGO IgG4-RD trial results – – Obexelimab Phase 3 INDIGO IgG4-RD trial results accepted for oral presentation at EULAR 2026 – – Obexelimab global Phase 2 SunStone SLE trial enrollment complete; topline results expected in Q4 2026 – – First subject dosed in Phase 1 trial of ZB021 (oral IL-17AA/AF inhibitor); initial clinical data expected by year-end – – Orelabrutinib global Phase 3 PriMroSe trial in patients with PPMS and global Phase 3 Monarch trial in patients with naSPMS ongoing – – Completed public offerings and entered into debt financing; cash runway extended into 2029 – WALTHAM, Mass., May 13, 2026 (GLOBE NEWSWIRE) -- Zenas BioPharma, Inc. (“Zenas,” “Zenas BioPharma” or the “Company”) (Nasdaq: ZBIO), a clinical-stage global biopharmaceutical company committed to being a leader in the development and commercialization of transformative therapies for patients living with autoimmune diseases, today reported financial results for the quarter ended March 31, 2026, and provided recent corporate updates. “This quarter we continued to execute across our portfolio and made meaningful progress toward our vision of becoming a fully integrated, global development and commercial-stage biopharmaceutical company that brings impactful treatments to patients living with autoimmune and chronic inflammatory diseases,” said Lonnie Moulder, Founder and Chief Executive Officer of Zenas. “Over the next three quarters, we expect to achieve important clinical and regulatory milestones, including the presentation of INDIGO study results at EULAR, the filing and acceptance of our marketing applications for obexelimab for IgG4-RD in the U.S. and Europe, topline results from the SunStone trial, and initial clinical data for ZB021, our oral IL-17 AA/AF inhibitor. With our balance sheet strengthened by recent financings, Zenas remains focused on preparing for the potential commercialization of obexelimab while continuing to advance our broader pipeline.” Corporate highlights Obexelimab, a CD-19 and FcgRIIb inhibitor of B cell function Obexelimab marketing applications for the treatment of Immunoglobulin G4-Related Disease (IgG4-RD) remain on track: Zenas expects to submit a Biologics License Application (BLA) to the U.S. Food and Drug Administration (FDA) this quarter and a Marketing Authorization Application (MAA) to the EMA in the second half of 2026. Reported positive results from the Phase 3 INDIGO registrational trial of obexelimab for the treatment of IgG4-RD in January 2026: Announced that obexelimab met the primary endpoint, demonstrating a highly statistically significant and clinically meaningful 56% reduction in the risk of IgG4-RD flare compared to placebo during the 52-week randomized placebo-controlled period. Obexelimab also met and demonstrated highly statistically significant activity compared to placebo on all four key secondary endpoints. Data from the INDIGO trial will be presented during an oral session at the European Alliance of Associations for Rheumatology (EULAR) 2026 Congress in London, UK, on June 4. More information on the Phase 3 INDIGO trial (NCT05662241) is available at clinicaltrials.gov. Enrollment completed in Phase 2 SunStone trial in Systemic Lupus Erythematosus (SLE) and topline results expected in 4Q 2026: Completed enrollment in the Phase 2 SunStone trial, a multicenter, randomized, double-blind, placebo-controlled trial to evaluate the efficacy and safety of obexelimab in patients with SLE. Zenas anticipates reporting topline overall and biomarker population results in the fourth quarter of 2026. More information on the Phase 2 SunStone trial (NCT06559163) is available at clinicaltrials.gov. ZB021, a novel oral, IL-17AA/AF inhibitor that blocks IL-17 AA homodimer and IL-17AF heterodimer signaling First subject dosed in Phase 1 trial of ZB021 in healthy volunteers: In May 2026, the first subject was dosed in the Phase 1 clinical trial of ZB021. The Phase 1 study is designed to evaluate the safety, tolerability, and pharmacokinetic profile of single ascending doses (SAD) and multiple ascending doses (MAD) of ZB021 in healthy volunteers and is being conducted in partnership with InnoCare Pharma in China. These data are expected by year-end 2026. Upon completion and evaluation of the SAD and MAD study, Zenas plans to initiate a proof-of-concept (POC) trial in North America to evaluate clinical activity and safety in psoriasis patients with results anticipated in 2027. Orelabrutinib, a highly selective CNS-penetrant Bruton’s Tyrosine Kinase (BTK) inhibitor Orelabrutinib Phase 3 PriMroSe Primary Progressive Multiple Sclerosis (PPMS) trial ongoing: PriMroSe, a Phase 3, global registration-directed, multicenter, randomized, double-blind, placebo-controlled trial to evaluate the efficacy and safety of orelabrutinib in patients with PPMS in is ongoing. More information on the Phase 3 PriMroSe trial (NCT07067463) is available at clinicaltrials.gov. Orelabrutinib Phase 3 Monarch non-active Secondary Progressive Multiple Sclerosis (naSPMS) trial ongoing: Monarch, a Phase 3, global registration-directed, multicenter, randomized, double-blind, placebo-controlled trial to evaluate the efficacy and safety of orelabrutinib in patients with naSPMS is ongoing. More information on the Phase 3 Monarch trial (NCT07299019) is available at clinicaltrials.gov. Early development programs ZB022, an oral, brain-penetrant, TYK2-JH2 inhibitor IND enabling studies ongoing: Subject to the results of IND enabling studies, Zenas expects to initiate a Phase 1 clinical study in 2027. ZB014, a half-life extended, anti-CD-19 and FcgRIIb monoclonal antibody (mAb) IND enabling studies ongoing: Developed using half-life extension technology for mAbs, and based on preclinical study results, ZB014 has the potential to provide the clinical activity and safety profile observed with obexelimab while offering a once-monthly dosing schedule. Zenas expects to advance the program into Phase 1 clinical development in 2027. Financing highlights Year to date the Company raised a total of $419.0 million in gross proceeds from concurrent convertible notes and common stock offerings, exercise of the overallotment option, and sales of common stock under the Company’s at-the-market (ATM) program. Cash, cash equivalents and investments as of March 31, 2026 of $718.5 million, along with the aggregate gross proceeds of $45.0 million from the underwriters’ exercise in full of their over-allotment option for the convertible notes and option to purchase additional shares of common stock, and assuming receipt of the potential $75 million milestone from Royalty Pharma and $75 million drawn from the debt facility with Pharmakon associated with achieving FDA marketing approval of obexelimab for IgG4-RD, the Company expects that its cash, cash equivalents and investments will fund its operating expenses and capital expenditure requirements at least through the second quarter of 2029. Financing included: $374.0 million public offerings: In March 2026, Zenas raised gross proceeds of approximately $300.0 million across concurrent public offerings of convertible notes and common stock. In April 2026, the Company issued an additional $30.0 million of convertible notes upon the underwriters’ exercise in full of their over-allotment option for gross proceeds of $30.0 million and an additional 750,000 shares of common stock upon the exercise in full of the underwriters’ option to purchase additional shares for gross proceeds of $15.0 million. In addition, during the first quarter of 2026, Zenas raised gross proceeds of approximately $74.0 million from sales of common stock under the ATM. $250 million debt facility with Pharmakon Advisors: In March 2026, Zenas entered into a five-year, up to $250 million senior secured debt facility with funds managed by Pharmakon Advisors, LP. First quarter 2026 financial results As of March 31, 2026, the Company’s cash, cash equivalents and investments were $718.5 million. Research and development (R&D) expenses were $60.4 million for the quarter ended March 31, 2026, compared to $34.9 million for the quarter ended March 31, 2025. The increase of $25.5 million in R&D expenses was primarily due to an increase in costs related to clinical trial and regulatory costs for orelabrutinib, an increase in costs related to clinical manufacturing and clinical trial costs for obexelimab and an increase in personnel costs including stock-based compensation expense primarily due to an increase in headcount. General and administrative (G&A) expenses were $16.9 million for the quarter ended March 31, 2026, compared to $12.4 million for the quarter ended March 31, 2025. The increase of $4.5 million in G&A expenses was primarily due to an increase in personnel costs, including stock-based compensation expense primarily due to an increase in headcount associated with pre-commercialization activities and other expenses primarily attributable to company growth and continued operations as a public company. Other (expense) income, net was $3.6 million of expense for the quarter ended March 31, 2026, compared to $3.6 million of income for the quarter ended March 31, 2025. The decrease of $7.2 million was primarily related to non-cash interest expense recognized related to the royalty obligation with Royalty Pharma, offset by interest income from higher cash and investment balances. Net loss was $81.0 million for the quarter ended March 31, 2026, compared to net loss of $33.6 million for the quarter ended March 31, 2025. About ObexelimabObexelimab is a bifunctional monoclonal antibody designed to bind both CD19 and FcgRIIb, which are broadly present across B cell lineage, to inhibit the activity of cells that are implicated in many autoimmune diseases without depleting them. This unique inhibitory mechanism of action and self-administered, subcutaneous injection regimen may broadly and effectively address the pathogenic role of the B cell lineage in chronic autoimmune disease. Obexelimab has been evaluated in eight clinical trials in a total of 383 subjects, including INDIGO. Obexelimab was well tolerated and demonstrated clinical activity across these clinical trials. The registrational Phase 3 INDIGO trial for Immunoglobulin G4-Related Disease met its primary endpoint and all four key secondary endpoints with high statistical significance. The trial continues to evaluate patients in the 3-year open label extension period which will further build upon the largest body of clinical data reported for IgG4-RD patients to date. A randomized Phase 2 trial for Systemic Lupus Erythematosus is ongoing and Zenas expects to report topline results, including biomarker data from this trial in the fourth quarter of 2026. About ZB021ZB021 is a novel potentially best-in-class oral small molecule IL-17AA/AF inhibitor being developed by Zenas BioPharma in partnership with InnoCare Pharma. ZB021 is designed to selectively block the signal transduction pathways of both the IL-17AA homodimer and IL-17AF heterodimer, inhibiting downstream pro-inflammatory cytokine and chemokine release. Preclinical studies have demonstrated potent anti-inflammatory activity, a favorable safety profile, and excellent Absorption, Distribution, Metabolism, and Excretion (ADME) properties. The IL-17 pathway has demonstrated broad utility across many rheumatic and dermatologic indications. Currently, no oral IL-17 inhibitors have been approved or are in late-stage development globally. ZB021's oral, small molecule profile may offer meaningful advantages over currently approved biologic IL-17 therapies in terms of convenience, compliance, and accessibility. Zenas licensed exclusive rights from InnoCare Pharma to develop, manufacture, and commercialize ZB021 in all fields of use worldwide, excluding greater China and Southeast Asia. About OrelabrutinibOrelabrutinib is a late-stage, potentially best-in-class, highly selective CNS-penetrant, oral, small molecule Bruton’s Tyrosine Kinase (BTK) inhibitor. In Multiple Sclerosis (MS), Zenas is advancing PriMroSe, a Phase 3 trial in Primary Progressive MS (PPMS), and Monarch, a Phase 3 trial in non-active Secondary Progressive MS (naSPMS). Orelabrutinib is approved for B cell malignancies in mainland China and Singapore, marketed by our partner InnoCare. About Zenas BioPharmaZenas is a clinical-stage global biopharmaceutical company committed to becoming a leader in the development and commercialization of transformative therapies for patients living with autoimmune diseases. Zenas’ core business strategy combines our experienced leadership team with a disciplined product candidate acquisition approach to identify, acquire and develop product candidates globally that we believe can provide superior clinical benefits to patients living with autoimmune diseases. Zenas is advancing two late-stage, potential franchise molecules, obexelimab and orelabrutinib. Obexelimab, Zenas’ lead product candidate, is a bifunctional monoclonal antibody designed to bind both CD19 and FcgRIIb, which are broadly present across B cell lineage, to inhibit the activity of cells that are implicated in many autoimmune diseases without depleting them. Zenas believes that obexelimab’s unique mechanism of action and self-administered, subcutaneous injection regimen may broadly and effectively address the pathogenic role of B cell lineage in chronic autoimmune disease. Orelabrutinib is a potentially best-in-class, highly selective CNS-penetrant, oral, small molecule BTK inhibitor. Orelabrutinib’s mechanism of action targets pathogenic B cells not only in the periphery but also within the CNS. Additionally, it directly modulates macrophages and microglial cells in the CNS, with the potential to address compartmentalized inflammation and disease progression in MS. Zenas’ earlier stage programs include ZB021, a novel, potentially best-in-class, oral small molecule IL-17AA/AF inhibitor, ZB022, a preclinical, potentially best-in-class, oral, brain-penetrant, TYK2 inhibitor, and ZB014, a preclinical, half-life extended anti-CD19 and FcgRIIb monoclonal antibody. For more information about Zenas BioPharma, please visit https://zenasbio.com/ and follow us on LinkedIn. Zenas BioPharma Forward-Looking StatementsThis press release contains “forward-looking statements” which involve risks, uncertainties and contingencies, many of which are beyond the control of the Company, which may cause actual results, performance, or achievements to differ materially from anticipated results, performance, or achievements. All statements other than statements of historical facts contained in this press release are forward-looking statements. In some cases, forward-looking statements can be identified by terms such as “may,” “will,” “should,” “expect,” “plan,” “anticipate,” “could,” “intend,” “target,” “project,” “contemplate,” “believe,” “estimate,” “predict,” “potential” or “continue” or the negative of these terms or other similar expressions, although not all forward-looking statements contain these words. Forward looking statements include, but are not limited to, statements concerning Zenas’s milestones, expectations and intentions, including the potential for obexelimab to become a meaningful therapy across multiple autoimmune diseases, the timing of the initiation of, results and data from clinical trials, including the timing of reporting the topline results from the SunStone trial; timing of reporting Phase 1 clinical data and, if successful, and the timing of initiation of and reporting clinical data in the Phase 1 (POC) clinical trial of ZB021 in patients with psoriasis; the timing of regulatory submissions, including timing of our submission of a BLA to FDA for obexelimab in IgG4-RD, our plans to submit a marketing application to the EMA for obexelimab in IgG4-RD; subject to IND clearance, the initiation of Phase 1 clinical studies of ZB022 and ZB014; our ability to draw down on the Pharmakon debt facility; receipt of additional funding under our Royalty Pharma and Pharmakon agreements contingent upon FDA approval of obexelimab; and our cash guidance.. The forward-looking statements in this press release speak only as of the date of this press release and are subject to a number of known and unknown risks, uncertainties and assumptions that could cause the Company’s actual results to differ materially from those anticipated in the forward-looking statements, including, but not limited to: the Company’s limited operating history, incurrence of substantial losses since the Company’s inception and anticipation of incurring substantial and increasing losses for the foreseeable future; the Company’s need for substantial additional financing to achieve the Company’s goals; the uncertainty of clinical development, which is lengthy and expensive, and characterized by uncertain outcomes, and risks related to additional costs or delays in completing, or failing to complete, the development and commercialization of the Company’s current product candidates or any future product candidates; delays or difficulties in the enrollment and dosing of patients in clinical trials; the impact of any significant adverse events or undesirable side effects caused by the Company’s product candidates; potential competition, including from large and specialty pharmaceutical and biotechnology companies, many of which already have approved therapies in the Company’s current indications; the Company’s ability to realize the benefits of the Company’s current or future collaborations or licensing arrangements and ability to successfully consummate future partnerships; the Company’s ability to obtain regulatory approval to commercialize any product candidate in the United States or any other jurisdiction, the risk that the data from our clinical trials is not sufficient to the satisfaction of the FDA or comparable foreign regulatory authorities to support the submission of a biologics license application or other comparable submission or to obtain regulatory approval for our product candidates for which we seek approval in the U.S. or elsewhere, and the risk that any such approval may be for a more narrow indication than the Company seeks; the Company’s dependence on the services of the Company’s senior management and other clinical and scientific personnel, and the Company’s ability to retain these individuals or recruit additional management or clinical and scientific personnel; the Company’s ability to grow the Company’s organization, and manage the Company’s growth and expansion of the Company’s operations; risks related to the manufacturing of the Company’s product candidates, which is complex, and the risk that the Company’s third-party manufacturers may encounter difficulties in production; the Company’s ability to obtain and maintain sufficient intellectual property protection for the Company’s product candidates or any future product candidates the Company may develop; the Company’s reliance on third parties to conduct the Company’s preclinical studies and clinical trials; the Company’s compliance with the Company’s obligations under the licenses granted to the Company by others, for the rights to develop and commercialize the Company’s product candidates; significant political, trade, regulatory developments, including changes in relations between the U.S. and China; risks related to the operations of the Company’s suppliers, many of which are located outside of the United States, including the Company’s current sole contract manufacturing organization for obexelimab for drug substance and drug product, WuXi Biologics (Hong Kong) Limited, and our partner, InnoCare, both of which are located in China; the risk that the Company’s indebtedness resulting from the Company’s loan agreement with Pharmakon Advisors LP, and the guarantors party to such agreement, or future indebtedness could adversely affect the Company’s financial condition or restrict the Company’s future operations; and other risks and uncertainties described in the section “Risk Factors” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2025 and Quarterly Report on Form 10-Q for the first quarter ended March 31, 2026, as well as other information we file with the Securities and Exchange Commission. The forward-looking statements in this press release are inherently uncertain, speak only as of the date of this press release and may prove incorrect. These statements are based upon information available to the Company as of the date of this press release and while the Company believes such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that the Company has conducted an exhaustive inquiry into, or review of, all potentially available relevant information. Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified and some of which are beyond the Company’s control, these forward-looking statements should not be relied upon as guarantees of future events. The events and circumstances reflected in the forward-looking statements may not be achieved or occur and actual future results, levels of activity, performance and events and circumstances could differ materially from those projected in the forward-looking statements. Moreover, the Company operates in an evolving environment. New risks and uncertainties may emerge from time to time, and management cannot predict all risks and uncertainties. Except as required by applicable law, the Company does not undertake any obligation to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events, changed circumstances or otherwise. The Zenas BioPharma word mark, logo mark, and the “lightning bolt” design are trademarks of Zenas BioPharma, Inc. or its affiliated companies. Investor and Media Contact:Argot [email protected]

Zenas BioPharma, Inc. has reported first-quarter 2026 results, recording a net loss of US$80.99 million, compared with US$33.57 million a year earlier, with basic and diluted loss per share from continuing operations rising to US$1.46 from US$0.80. The widening loss underscores how the company’s cost base or investment spend has grown materially year on year, even as it remains in a loss-making phase. We will now examine how this sharp year-on-year increase in net loss shapes Zenas BioPharma’s investment narrative and risk profile. We've uncovered the 13 dividend fortresses yielding 5%+ that don't just survive market storms, but thrive in them. To own Zenas BioPharma today, you have to believe that obexelimab’s emerging profile across IgG4-RD and relapsing MS can ultimately justify heavy upfront investment and ongoing losses. The latest quarter’s US$80.99 million net loss, sharply higher than a year ago, reinforces that this is still very much a funding and execution story rather than an earnings one. Recent financing moves, including a US$100 million follow-on offering and up to US$250 million in term loans, have bought time for key regulatory and partnering catalysts, but at the cost of dilution and higher financial obligations. Against a share price that has fallen year to date, the bigger loss figure raises the stakes around cash burn and any delay in converting positive trial data into approvals or commercial deals. Unless you think this spending curve is proportionate to the opportunity, the risk side of the equation will loom larger after this update. However, one funding risk now looks even more important to understand in detail. Upon reviewing our latest valuation report, Zenas BioPharma's share price might be too optimistic. One fair value estimate from the Simply Wall St Community sits at US$42 per share, showing just a single, concentrated viewpoint. Set that against rising losses and fresh financing needs, and it becomes clear why different investors may reach very different conclusions about how Zenas’ execution from here could influence future outcomes. Explore another fair value estimate on Zenas BioPharma - why the stock might be worth just $42.00! Disagree with this assessment? Extraordinary investment returns rarely come from following the herd, so go with your instincts. A great starting point for your Zenas BioPharma research is our analysis highlighting 2 key rewards and 2 important warning signs that could impact your investment decision. Our free Zenas BioPharma research report provides a comprehensive fundamental analysis summarized in a single visual - the Snowflake - making it easy to evaluate Zenas BioPharma's overall financial health at a glance. Our top stock finds are flying under the radar-for now. Get in early: Outshine the giants: these 16 early-stage AI stocks could fund your retirement. AI is about to change healthcare. These 33 stocks are working on everything from early diagnostics to drug discovery. The best part - they are all under $10b in market cap - there's still time to get in early. Find 44 companies with promising cash flow potential yet trading below their fair value. This article by Simply Wall St is general in nature. We provide commentary based on historical data and analyst forecasts only using an unbiased methodology and our articles are not intended to be financial advice. It does not constitute a recommendation to buy or sell any stock, and does not take account of your objectives, or your financial situation. We aim to bring you long-term focused analysis driven by fundamental data. Note that our analysis may not factor in the latest price-sensitive company announcements or qualitative material. Simply Wall St has no position in any stocks mentioned. Companies discussed in this article include ZBIO. Have feedback on this article? Concerned about the content? Get in touch with us directly. Alternatively, email [email protected]

- Obexelimab marketing applications for the treatment of IgG4-RD expected to be submitted to the FDA in Q2 2026 and the EMA in H2 2026 based on the Phase 3 INDIGO trial results - - Topline results of the global Phase 2 SunStone trial of obexelimab in SLE expected in Q4 2026 - - New, half-life extended anti-CD-19 and FcγRIIb mAb (ZB014) progressing toward clinical development - - Global orelabrutinib Phase 3 trial for primary progressive multiple sclerosis (MS) ongoing; global Phase 3 trial for non-active secondary progressive MS expected to be initiated in Q1 2026 - - Oral, IL-17AA/AF inhibitor (ZB021) Phase 1 trial expected to be initiated in 2Q 2026 with initial clinical data by year-end - - Up to $250 million non-dilutive, multi-tranche debt financing secured from Pharmakon - WALTHAM, Mass., March 16, 2026 (GLOBE NEWSWIRE) -- Zenas BioPharma, Inc. (“Zenas” or the “Company”) (Nasdaq: ZBIO), a clinical-stage global biopharmaceutical company committed to being a leader in the development and commercialization of transformative therapies for patients living with autoimmune diseases, today reported financial results for the quarter and year ended December 31, 2025, and provided recent corporate updates. "Following the highly positive Phase 3 INDIGO results reported earlier this year, we enter 2026 with strong momentum as we prepare for the potential commercialization of obexelimab for the treatment of IgG4-RD. We are on track to submit obexelimab marketing applications for the treatment of IgG4-RD to the FDA in the second quarter and to the EMA in the second half of the year, both major milestones for the program and patients living with this disease,” said Lonnie Moulder, Founder and Chief Executive Officer of Zenas. “We look forward to progressing multiple Zenas pipeline programs this year, including the orelabrutinib progressive MS Phase 3 studies, clinical development of our oral IL-17 inhibitor, ZB021, and the advancement of an exciting new molecule, ZB014, a half-life extended anti-CD-19 and FcγRIIb antibody. In addition, we expect to report topline overall and biomarker population results of the Phase 2 SunStone trial of obexelimab in SLE. Collectively, these programs represent the foundation for compelling franchises across numerous areas of unmet need for patients living with immune mediated diseases. We are also very pleased to announce today a non-dilutive financing arrangement with Pharmakon, a respected leader in strategic life sciences funding. This partnership strengthens our balance sheet and provides us with the financial flexibility to commercialize obexelimab while investing in our broader pipeline." Corporate highlights Obexelimab, a CD-19 and FcγRIIb inhibitor of B cell function Reported positive results from the Phase 3 INDIGO registrational trial of obexelimab for the treatment of Immunoglobulin G4-Related Disease (IgG4-RD) in January 2026: Announced that obexelimab met the primary endpoint, demonstrating a highly statistically significant and clinically meaningful 56% reduction in the risk of IgG4-RD flare compared to placebo during the 52-week randomized placebo-controlled period. Obexelimab also met and demonstrated highly statistically significant activity compared to placebo on all four key secondary endpoints. Zenas expects to submit a Biologics License Application (BLA) to the U.S. Food and Drug Administration (FDA) in the second quarter of 2026 and a Marketing Authorization Application (MAA) to the EMA in the second half of 2026. The Company expects that full data from the INDIGO trial will be presented at a future medical meeting. More information on the Phase 3 INDIGO trial (NCT05662241) is available at clinicaltrials.gov. Topline results of the Phase 2 SunStone trial in Systemic Lupus Erythematosus (SLE) expected 4Q 2026: Zenas anticipates reporting topline overall and biomarker population results in the fourth quarter of 2026 for the Phase 2 SunStone trial, a multicenter, randomized, double-blind, placebo-controlled trial to evaluate the efficacy and safety of obexelimab in patients with SLE. More information on the Phase 2 SunStone trial (NCT06559163) is available at clinicaltrials.gov. A new, half-life extended anti-CD-19 and FcγRIIb mAb (ZB014) is progressing toward clinical development: Developed using half-life extension technology for monoclonal antibodies, and based on preclinical study results, ZB014 has the potential to provide the clinical activity and safety profile observed with obexelimab while offering a once-monthly dosing schedule. Orelabrutinib, a highly selective CNS-penetrant Bruton’s Tyrosine Kinase (BTK) inhibitor Initiated Orelabrutinib Phase 3 PriMroSe Primary Progressive Multiple Sclerosis (PPMS) trial: Initiated PriMroSe, a Phase 3, global registration-directed, multicenter, randomized, double-blind, placebo-controlled trial to evaluate the efficacy and safety of orelabrutinib in patients with PPMS in the third quarter of 2025. More information on the Phase 3 PriMroSe trial (NCT07067463) is available at clinicaltrials.gov. Orelabrutinib Phase 3 Monarch trial for non-active Secondary Progressive Multiple Sclerosis (naSPMS) planned: Monarch, a Phase 3, global registration-directed, multicenter, randomized, double-blind, placebo-controlled trial to evaluate the efficacy and safety of orelabrutinib in patients with naSPMS is expected to initiate in the first quarter of 2026. More information on the Phase 3 Monarch trial (NCT07299019) is available at clinicaltrials.gov. Other corporate highlights $250 million debt facility with Pharmakon Advisors: In March 2026, Zenas entered into a five-year, up to $250 million senior secured debt facility with funds managed by Pharmakon Advisors, LP. The committed capital will be available to Zenas in five tranches with the first $75 million issued at closing, and an additional $175 million available to be drawn and subject to certain obexelimab IgG4-RD regulatory and commercial conditions, through April 30, 2029, $125 million of which is at Zenas’ discretion. Investment funds managed by Pharmakon Advisors are entitled to receive mid-single digit interest payments over the Secured Overnight Financing Rate (SOFR). Other pipeline updates ZB021, a novel oral, IL-17AA/AF inhibitor that blocks IL-17 AA homodimer and IL-17AF heterodimer signaling with best-in-class potential Investigational New Drug (IND) enabling studies complete: Zenas expects initiation of Phase 1 clinical development for ZB021 in the second quarter of 2026 and to report initial clinical data by year-end 2026. Pending Phase 1 data, Zenas expects to advance development of ZB021 for rheumatic and/or dermatologic diseases. ZB022, an oral, brain-penetrant, TYK2 inhibitor with best-in-class potential IND enabling studies ongoing: Zenas expects to complete IND enabling studies for ZB022 in 2026 and then advance the program into Phase 1 clinical development upon IND clearance. Fourth quarter and year end 2025 financial results As of December 31, 2025, the Company’s cash, cash equivalents and investments were $360.5 million. The Company expects that its cash, cash equivalents and investments, as of December 31, 2025, together with the net proceeds received to date in the first quarter of 2026 from sales under our ATM program and the proceeds available from the debt arrangement with investment funds managed by Pharmakon will be sufficient to fund its operating expenses and capital expenditure requirements into the second quarter of 2027, and assuming receipt of a potential $75.0 million from the investment funds managed by Pharmakon and $75.0 million from Royalty Pharma contingent upon FDA approval of obexelimab for the treatment of IgG4-RD, the Company expects that its cash, cash equivalents and investments will be sufficient to fund its operating expenses and capital expenditure requirements into the fourth quarter of 2027. Revenue was $10.0 million for the year ended December 31, 2025, related to the one-time non-refundable upfront cash payment received pursuant to a license agreement with Zai Lab (Hong Kong) Limited (Zai) for greater China rights to our thyroid eye disease program (ZB001/ZB011) that was recognized upon delivery of the license and related technology transfer. Revenue was $5.0 million for the year ended December 31, 2024, related to the upfront payment received pursuant to a novation agreement with Tenacia Biotechnology (Hong Kong) Co., Limited (Tenacia) associated with the greater China rights for ZB005, which were originally licensed from Dianthus Therapeutics. Research and development (R&D) expenses were $55.7 million for the quarter ended December 31, 2025, compared to $49.2 million for the quarter ended December 31, 2024. The increase of $6.5 million was due to an increase in personnel costs including stock-based compensation expense, an increase in clinical trial and regulatory costs related to orelabrutinib and development costs related to our other global programs, partially offset by a decrease in clinical trial and manufacturing costs related to obexelimab. R&D expenses were $168.1 million for the year ended December 31, 2025, compared to $139.1 million for the year ended December 31, 2024. The increase of $29.0 million was due to an increase in personnel costs including stock-based compensation expense, an increase in clinical trial and manufacturing costs related to obexelimab and an increase in clinical trial and regulatory costs related to our recently acquired product candidate, orelabrutinib, partially offset by a decrease in development costs related to our partnered regional programs as a result of transitioning these programs to Tenacia and Zai. General and administrative (G&A) expenses were $15.6 million for the quarter ended December 31, 2025, compared to $11.5 million for the quarter ended December 31, 2024. The increase of $4.1 million in G&A expenses was due to an increase in personnel costs, including stock-based compensation expense, pre-commercialization activities and other expenses associated with operating as a public company. G&A expenses were $53.3 million for the year ended December 31, 2025, compared to $29.7 million for the year ended December 31, 2024. The increase of $23.6 million in G&A expenses was due to an increase in personnel costs, including stock-based compensation expense, pre-commercialization activities and an increase in professional fees including legal, audit and tax expenses, and other expenses associated with business development activities and operating as a public company. Acquired in-process research and development (AIPR&D) expenses were $166.7 million for the quarter ended December 31, 2025, which related to the upfront cash payment of $30.0 million and $136.7 million of non-cash expense related to the equity consideration pursuant to a license agreement with InnoCare under which we acquired rights to orelabrutinib, ZB021 and ZB022. The Company did not recognize AIPR&D expense for the quarter ended December 31, 2024. AIPR&D expenses were $171.7 million for the year ended December 31, 2025, which related to the upfront cash payment of $35.0 million and $136.7 million of non-cash expense related to the equity consideration pursuant to the license agreement with InnoCare. The Company did not recognize AIPR&D expense for the year ended December 31, 2024. Other expense, net was $2.4 million for the quarter ended December 31, 2025, compared to other income, net of $3.4 million for the quarter ended December 31, 2024. The difference of $5.8 million primarily related to non-cash interest expense recognized related to the royalty obligation associated with obexelimab under a royalty purchase agreement that we entered into with Royalty Pharma, offset by interest income from higher cash and investment balances. Other income, net was $5.2 million for the year ended December 31, 2025, compared $7.3 million for the year ended December 31, 2024. The decrease of $2.1 million primarily related to non-cash interest expense recognized related to the royalty obligation, offset by interest income from higher cash and investment balances. Net loss was $240.4 million for the quarter ended December 31, 2025, compared to a net loss of $52.6 million for the quarter ended December 31, 2024. Net loss was $377.7 million for the year ended December 31, 2025, compared to a net loss of $157.0 million for the year ended December 31, 2024. About Obexelimab Obexelimab is a bifunctional monoclonal antibody designed to bind both CD19 and FcγRIIb, which are broadly present across B cell lineage, to inhibit the activity of cells that are implicated in many autoimmune diseases without depleting them. This unique inhibitory mechanism of action and self-administered, subcutaneous injection regimen may broadly and effectively address the pathogenic role of the B cell lineage in chronic autoimmune disease. Obexelimab has been evaluated in eight clinical trials in a total of 383 subjects, including INDIGO. Obexelimab was well tolerated and demonstrated clinical activity across these clinical trials. The registrational Phase 3 INDIGO trial for Immunoglobulin G4-Related Disease met its primary endpoint and all four key secondary endpoints with high statistical significance. The trial continues to evaluate patients in the 3-year open label extension period which will further build upon the largest body of clinical data reported for IgG4-RD patients to date. A randomized Phase 2 trial for Systemic Lupus Erythematosus is ongoing and Zenas expects to report topline results, including biomarker data from this trial in the fourth quarter of 2026. About Orelabrutinib Orelabrutinib is a late-stage, potentially best-in-class, highly selective CNS-penetrant, oral, small molecule Bruton’s Tyrosine Kinase (BTK) inhibitor. In Multiple Sclerosis (MS), Zenas is advancing PriMroSe, a Phase 3 trial in Primary Progressive MS (PPMS). Monarch, a Phase 3 trial in Secondary Progressive MS (SPMS) is expected to initiate in the first quarter of 2026. Orelabrutinib is approved for B cell malignancies in mainland China and Singapore, marketed by our partner InnoCare. About Zenas BioPharma, Inc. Zenas is a clinical-stage global biopharmaceutical company committed to becoming a leader in the development and commercialization of transformative therapies for patients living with autoimmune diseases. Our core business strategy combines our experienced leadership team with a disciplined product candidate acquisition approach to identify, acquire and develop product candidates globally that we believe can provide meaningful clinical benefits to patients living with autoimmune diseases. Zenas is advancing two late-stage, potential franchise molecules, obexelimab and orelabrutinib. Obexelimab, Zenas’ lead product candidate, is a bifunctional monoclonal antibody designed to bind both CD19 and FcγRIIb, which are broadly present across B cell lineage, to inhibit the activity of cells that are implicated in many autoimmune diseases without depleting them. We believe that obexelimab’s unique inhibitory mechanism of action and self-administered, subcutaneous injection regimen may broadly and effectively address the pathogenic role of B cell lineage in chronic autoimmune disease. Orelabrutinib is a potentially best-in-class, highly selective central nervous system (CNS)-penetrant, oral, small molecule BTK inhibitor. Orelabrutinib’s mechanism of action targets pathogenic B cells not only in the periphery but also within the CNS. Additionally, it directly modulates macrophages and microglial cells in the CNS, with the potential to address compartmentalized inflammation and disease progression in Multiple Sclerosis (MS). Zenas’ earlier stage programs include ZB021, a preclinical, potentially best-in-class, oral, IL-17AA/AF inhibitor, and ZB022, a preclinical, potentially best-in-class, oral, brain-penetrant, TYK2 inhibitor. For more information about Zenas BioPharma, please visit https://zenasbio.com/ and follow us on LinkedIn. Zenas BioPharma Forward-Looking Statements This press release contains “forward-looking statements” which involve risks, uncertainties and contingencies, many of which are beyond the control of the Company, which may cause actual results, performance, or achievements to differ materially from anticipated results, performance, or achievements. All statements other than statements of historical facts contained in this press release are forward-looking statements. In some cases, forward-looking statements can be identified by terms such as “may,” “will,” “should,” “expect,” “plan,” “anticipate,” “could,” “intend,” “target,” “project,” “contemplate,” “believe,” “estimate,” “predict,” “potential” or “continue” or the negative of these terms or other similar expressions, although not all forward-looking statements contain these words. Forward-looking statements include, but are not limited to, statements concerning Zenas’s milestones, expectations and intentions, including the potential for obexelimab to become a meaningful therapy across multiple autoimmune diseases, the timing of the initiation of, results and data from clinical trials, including the timing of reporting the topline results from the SunStone trial and the timing of initiation of the Phase 3 clinical trial of orelabrutinib in patients with naSPMS; the timing of regulatory submissions, including timing of our submission of a BLA to FDA for obexelimab in IgG4-RD, our plans to submit a marketing application to the EMA for obexelimab in IgG4-RD; subject to IND clearance, the initiation of Phase 1 clinical studies and indications selections of ZB021 and ZB022; the potential of ZB014; our ability to draw down on the Pharmakon debt facility; receipt of additional funding under our Royalty Pharma and Pharmakon agreements contingent upon FDA approval of obexelimab; and our cash guidance. The forward-looking statements in this press release speak only as of the date of this press release and are subject to a number of known and unknown risks, uncertainties and assumptions that could cause the Company’s actual results to differ materially from those anticipated in the forward-looking statements, including, but not limited to: the Company’s limited operating history, incurrence of substantial losses since the Company’s inception and anticipation of incurring substantial and increasing losses for the foreseeable future; the Company’s need for substantial additional financing to achieve the Company’s goals; the uncertainty of clinical development, which is lengthy and expensive, and characterized by uncertain outcomes, and risks related to additional costs or delays in completing, or failing to complete, the development and commercialization of the Company’s current product candidates or any future product candidates; delays or difficulties in the enrollment and dosing of patients in clinical trials; the impact of any significant adverse events or undesirable side effects caused by the Company’s product candidates; potential competition, including from large and specialty pharmaceutical and biotechnology companies, many of which already have approved therapies in the Company’s current indications; the Company’s ability to realize the benefits of the Company’s current or future collaborations or licensing arrangements and ability to successfully consummate future partnerships; the Company’s ability to obtain regulatory approval to commercialize any product candidate in the United States or any other jurisdiction, the risk that the data from our clinical trials is not sufficient to the satisfaction of the FDA or comparable foreign regulatory authorities to support the submission of a biologics license application or other comparable submission or to obtain regulatory approval for our product candidates for which we seek approval in the U.S. or elsewhere, and the risk that any such approval may be for a more narrow indication than the Company seeks; the Company’s dependence on the services of the Company’s senior management and other clinical and scientific personnel, and the Company’s ability to retain these individuals or recruit additional management or clinical and scientific personnel; the fact that the Company’s independent registered public accounting firm has expressed substantial doubt about the Company’s ability to continue as a going concern in its report on the Company’s audited financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2025; the Company’s ability to grow the Company’s organization, and manage the Company’s growth and expansion of the Company’s operations; risks related to the manufacturing of the Company’s product candidates, which is complex, and the risk that the Company’s third-party manufacturers may encounter difficulties in production; the Company’s ability to obtain and maintain sufficient intellectual property protection for the Company’s product candidates or any future product candidates the Company may develop; the Company’s reliance on third parties to conduct the Company’s preclinical studies and clinical trials; the Company’s compliance with the Company’s obligations under the licenses granted to the Company by others, for the rights to develop and commercialize the Company’s product candidates; significant political, trade, regulatory developments, including changes in relations between the U.S. and China; risks related to the operations of the Company’s suppliers, many of which are located outside of the United States, including the Company’s current sole contract manufacturing organization for obexelimab drug substance and drug product, WuXi Biologics (Hong Kong) Limited, and our partner, InnoCare, both of which are located in China; the risk that the Company’s indebtedness resulting from the Company’s loan agreement with Pharmakon Advisors LP, and the guarantors party to such agreement, or future indebtedness could adversely affect the Company’s financial condition or restrict the Company’s future operations; and other risks and uncertainties described in the section “Risk Factors” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2025, as well as other information we file with the Securities and Exchange Commission. The forward-looking statements in this press release are inherently uncertain, speak only as of the date of this press release and may prove incorrect. These statements are based upon information available to the Company as of the date of this press release and while the Company believes such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that the Company has conducted an exhaustive inquiry into, or review of, all potentially available relevant information. Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified and some of which are beyond the Company’s control, these forward-looking statements should not be relied upon as guarantees of future events. The events and circumstances reflected in the forward-looking statements may not be achieved or occur and actual future results, levels of activity, performance and events and circumstances could differ materially from those projected in the forward-looking statements. Moreover, the Company operates in an evolving environment. New risks and uncertainties may emerge from time to time, and management cannot predict all risks and uncertainties. Except as required by applicable law, the Company does not undertake to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events, changed circumstances or otherwise. The Zenas BioPharma word mark, logo mark, and the “lightning bolt” design are trademarks of Zenas BioPharma, Inc. or its affiliated companies. Investor and Media Contact: Argot Partners [email protected]

- Obexelimab met the primary endpoint with a 95% relative reduction in new gadolinium (Gd)-enhancing T1 lesions compared with placebo over weeks 8 and 12 (p=0.0009) - - Separately announced 24-week data support the robust and durable activity of obexelimab and further validate its unique inhibitory mechanism of action - - Obexelimab was well tolerated, and no new safety signals were observed - WALTHAM, Mass., Feb. 09, 2026 (GLOBE NEWSWIRE) -- Zenas BioPharma, Inc. (“Zenas,” “Zenas BioPharma” or the “Company”) (Nasdaq: ZBIO), a clinical-stage global biopharmaceutical company committed to being a leader in the development and commercialization of transformative therapies for patients living with autoimmune diseases, today announced that results from the Phase 2 MoonStone trial of obexelimab in Relapsing Multiple Sclerosis (RMS) were presented in a late-breaking oral presentation at the Americas Committee for Treatment and Research in Multiple Sclerosis (ACTRIMS) Forum 2026, which took place from February 5-7, 2026 in San Diego, California. Obexelimab met the primary endpoint, demonstrating a highly statistically significant 95% relative reduction in the cumulative number of new gadolinium (Gd)-enhancing (GdE) T1 hyperintense lesions over week 8 and week 12 compared with placebo (p=0.0009). Near-complete suppression of new GdE T1 hyperintense lesions, markers of active inflammation, was observed with obexelimab by 8 weeks of treatment and was sustained through week 12. The adjusted mean number of new GdE T1 hyperintense lesions per scan was 0.01 (95% CI: 0.00, 0.06) in the obexelimab group compared to 0.23 (95% CI: 0.11, 0.51) with placebo. Over weeks 8 and 12, only two new GdE T1 lesions were observed in obexelimab-treated patients compared to 19 in placebo-treated patients, with 97.2% of obexelimab treated patients free from T1 lesions over this period. Consistent with the inhibitory mechanism of obexelimab, mean B cell values remained within the normal range for obexelimab-treated patients. The safety profile of obexelimab was consistent with that observed in prior completed trials, including cases of infections and hypersensitivity, most commonly mild injection site reactions. Separately announced 24-week data further confirm the robust and durable activity of obexelimab. The highly statistically significant reductions in total GdE T1 lesions observed with obexelimab over weeks 8 and 12 were maintained through week 24; unadjusted means were 0.87 at baseline, 0.08 at week 12 and 0.04 at week 24 for obexelimab indicating a 95% reduction. Obexelimab meaningfully reduced serum Neurofilament Light (NfL) by 40% through week 24; 15.28 pg/mL at baseline declining to 12.7 pg/mL at week 12 and 9.2 pg/mL at week 24. New and/or enlarging T2 lesions were also lower in the obexelimab arm and the Expanded Disability Status Scale (EDSS) scores were stable, indicating a lack of progression in physical disability. No new safety signals were observed at week 24. “We are very pleased that the MoonStone study was selected as a late-breaker oral presentation at ACTRIMS Forum 2026. Further, we are excited to share today that through week 24 of the MoonStone trial, obexelimab demonstrated robust and durable activity, including near complete elimination of gadolinium-enhancing T1 hyperintense lesions. The MoonStone 12-week primary endpoint results and 24-week data provide additional strong validation of obexelimab and the potential of B cell inhibition to offer meaningful clinical activity in a wide range of autoimmune diseases,” said Lonnie Moulder, Founder and Chief Executive Officer of Zenas. “With its unique mechanism of action, compelling safety and tolerability profile, and at-home subcutaneous self-administration, obexelimab has the potential to become a franchise molecule and meaningfully impact the lives of patients living with autoimmune diseases. We look forward to reporting on additional progress this year, including the submission of marketing applications for Immunoglobulin G4-Related Disease to the U.S. FDA and the European Medicines Agency and topline results from our Phase 2 SunStone trial for Systemic Lupus Erythematosus.” The ongoing open-label expansion portion of the Phase 2 MoonStone trial continues to follow patients for longer-term outcomes. Within Multiple Sclerosis, Zenas is currently advancing orelabrutinib, a potentially best-in-class, highly selective central nervous system (CNS)-penetrant, oral, small molecule Bruton’s Tyrosine Kinase (BTK) inhibitor. Orelabrutinib is being studied in a global Phase 3 clinical trial in patients with Primary Progressive Multiple Sclerosis (PPMS). Zenas also expects to initiate a global Phase 3 trial of orelabrutinib in patients with non-active Secondary Progressive Multiple Sclerosis (naSPMS) in this quarter. About Multiple Sclerosis Multiple Sclerosis (MS) is a chronic, autoimmune-mediated disorder of the Central Nervous System (CNS). According to the Multiple Sclerosis International Federation, approximately 2.9 million people worldwide are currently living with MS. The disease disproportionately affects females, and its highest prevalence is observed in North America, Europe and Australia. MS develops when the immune system aberrantly targets the myelin sheath – the protective insulation surrounding axons in the brain, spinal cord and optic nerves – leading to inflammation, demyelination and axonal injury. This pathological cascade disrupts neuronal signal transmission and results in a heterogeneous range of clinical manifestations, including motor weakness, fatigue, and cognitive and visual disturbances. Over time, progressive neurodegeneration contributes to irreversible disability progression. MS onset typically occurs between 20 and 40 years of age, making MS the leading cause of non-traumatic neurological disability in young adults. MS is categorized into three main subtypes, Relapsing Multiple Sclerosis (RMS), Secondary Progressive Multiple Sclerosis (SPMS) and Primary Progressive Multiple Sclerosis (PPMS); all three subtypes are associated with ongoing neuroaxonal loss from the earliest stages of the disease, even in the absence of overt clinical progression. Delays in diagnosis and treatment accelerate disability accumulation, reduce quality of life and increase socioeconomic burden. Consequently, early intervention with highly effective therapies is a key objective in disease management to slow or halt inflammatory and neurodegenerative processes and stop disability progression. RMS is characterized by distinct episodes of new or worsening neurological symptoms (relapses), followed by partial or complete remission. Approximately 85% of patients are initially diagnosed with RMS. Approximately 20-30% of treated RMS patients transition to SPMS, defined by continuous disability progression with or without relapses. Currently, there are no approved therapies for non-relapsing SPMS. PPMS represents 10-15% of all MS diagnoses and is characterized by a steady increase in disability without relapses from disease onset. Currently there is only one approved therapy for PPMS. About the Phase 2 MoonStone Trial The Phase 2 MoonStone trial, which enrolled 116 patients, is a randomized, double-blind, placebo-controlled trial, to evaluate the efficacy and safety of obexelimab in patients with Relapsing Multiple Sclerosis (RMS). The trial followed a standard design using magnetic resonance imaging (MRI) endpoints that have historically been highly predictive of successful outcome in large, randomized trials using an endpoint of annualized relapse rate in an RMS study population. After an initial screening period, patients were randomized 2:1 to receive either 250 mg of obexelimab or placebo via subcutaneous injection once weekly over a 12-week double-blinded treatment period. The primary endpoint is the cumulative number of new Gd-enhancing T1 hyperintense lesions over week 8 and week 12 as measured by brain MRI. Secondary and exploratory endpoints include using standardized assessments, imaging, and biomarkers to evaluate the impact on disease progression. Upon completion of the double-blinded phase, all patients enter a 12-week open-label period in which those previously on placebo transition to obexelimab treatment, while those originally assigned to obexelimab continue therapy. During this open-label period, secondary and exploratory endpoints will assess obexelimab’s clinical activity through week 24. Upon completion of the open-label period, all trial participants had the option to enroll in a 52-week open label extension for continued obexelimab treatment and the assessment of long-term outcomes. About Obexelimab Obexelimab is a bifunctional monoclonal antibody designed to bind both CD19 and FcγRIIb, which are broadly present across B cell lineage, to inhibit the activity of cells that are implicated in many autoimmune diseases without depleting them. This unique inhibitory mechanism of action and self-administered, subcutaneous injection regimen may broadly and effectively address the pathogenic role of the B cell lineage in chronic autoimmune disease. Obexelimab has been evaluated in eight clinical trials in a total of 383 subjects. Obexelimab was well tolerated and demonstrated clinical activity across these clinical trials. The registrational Phase 3 INDIGO trial for Immunoglobulin G4-Related Disease (IgG4-RD) met its primary endpoint and all four key secondary endpoints with high statistical significance. Zenas remains on track to submit a Biologics License Application (BLA) to the U.S. Food and Drug Administration (FDA) in the second quarter of 2026 and a Marketing Authorization Application (MAA) to the European Medicines Agency (EMA) in the second half of 2026. The trial continues to evaluate patients in the 3-year open label extension period which will further build upon the largest body of clinical data reported for IgG4-RD patients to date. A randomized Phase 2 trial for Systemic Lupus Erythematosus is ongoing and Zenas expects to report topline results, including biomarker data from this trial in the fourth quarter of 2026. About Zenas BioPharma, Inc. Zenas is a clinical-stage global biopharmaceutical company committed to becoming a leader in the development and commercialization of transformative therapies for patients living with autoimmune diseases. Our core business strategy combines our experienced leadership team with a disciplined product candidate acquisition approach to identify, acquire and develop product candidates globally that we believe can provide meaningful clinical benefits to patients living with autoimmune diseases. Zenas is advancing two late-stage, potential franchise molecules, obexelimab and orelabrutinib. Obexelimab, Zenas’ lead product candidate, is a bifunctional monoclonal antibody designed to bind both CD19 and FcγRIIb, which are broadly present across B cell lineage, to inhibit the activity of cells that are implicated in many autoimmune diseases without depleting them. We believe that obexelimab’s unique inhibitory mechanism of action and self-administered, subcutaneous injection regimen may broadly and effectively address the pathogenic role of B cell lineage in chronic autoimmune disease. Orelabrutinib is a potentially best-in-class, highly selective central nervous system (CNS)-penetrant, oral, small molecule BTK inhibitor. Orelabrutinib’s mechanism of action targets pathogenic B cells not only in the periphery but also within the CNS. Additionally, it directly modulates macrophages and microglial cells in the CNS, with the potential to address compartmentalized inflammation and disease progression in Multiple Sclerosis (MS). Zenas’ earlier stage programs include ZB021, a preclinical, potentially best-in-class, oral, IL-17AA/AF inhibitor, and ZB022, a preclinical, potentially best-in-class, oral, brain-penetrant, TYK2 inhibitor. Zenas expects to initiate Phase 1 clinical development for ZB021 in 2026. Pending Phase 1 data, Zenas expects to advance development of ZB021 for rheumatic and/or dermatologic diseases. In addition, Zenas expects to initiate Phase 1 clinical development for ZB022 in 2026. Pending Phase 1 data, Zenas expects to advance development of ZB022 for neurologic diseases. For more information about Zenas BioPharma, please visit https://zenasbio.com/ and follow us on LinkedIn. Zenas BioPharma Forward-Looking Statements This press release contains “forward-looking statements” which involve risks, uncertainties and contingencies, many of which are beyond the control of the Company, which may cause actual results, performance, or achievements to differ materially from anticipated results, performance, or achievements. All statements other than statements of historical facts contained in this press release are forward-looking statements. In some cases, forward-looking statements can be identified by terms such as “may,” “will,” “should,” “expect,” “plan,” “anticipate,” “could,” “intend,” “target,” “project,” “contemplate,” “believe,” “estimate,” “predict,” “potential” or “continue” or the negative of these terms or other similar expressions, although not all forward-looking statements contain these words. Forward-looking statements include, but are not limited to, statements concerning Zenas’s milestones, expectations and intentions, including the potential for obexelimab to become a franchise molecule and a meaningful therapy across multiple autoimmune diseases and to address the pathogenic role of B cells in autoimmune diseases, the timing of the initiation of, results and data from clinical trials, including the timing of reporting the topline results from the SunStone trial and the timing of initiation of the Phase 3 clinical trial of orelabrutinib in patients with naSPMS; the timing of regulatory submissions, including timing of our submission of a BLA to FDA for obexelimab in IgG4-RD, our plans to submit a marketing application to the EMA for obexelimab in IgG4-RD; subject to IND clearance, the initiation of Phase 1 clinical studies and indications selections of ZB021 and ZB022; the potential of obexelimab to address underlying disease activity; and the potential benefits, development and commercialization of orelabrutinib and obexelimab. The forward-looking statements in this press release speak only as of the date of this press release and are subject to a number of known and unknown risks, uncertainties and assumptions that could cause the Company’s actual results to differ materially from those anticipated in the forward-looking statements, including, but not limited to: the Company’s limited operating history, incurrence of substantial losses since the Company’s inception and anticipation of incurring substantial and increasing losses for the foreseeable future; the Company’s need for substantial additional financing to achieve the Company’s goals; the uncertainty of clinical development, which is lengthy and expensive, and characterized by uncertain outcomes, and risks related to additional costs or delays in completing, or failing to complete, the development and commercialization of the Company’s current product candidates or any future product candidates; delays or difficulties in the enrollment and dosing of patients in clinical trials; the impact of any significant adverse events or undesirable side effects caused by the Company’s product candidates; potential competition, including from large and specialty pharmaceutical and biotechnology companies, many of which already have approved therapies in the Company’s current indications; the Company’s ability to realize the benefits of the Company’s current or future collaborations or licensing arrangements and ability to successfully consummate future partnerships; the Company’s ability to obtain regulatory approval to commercialize any product candidate in the United States or any other jurisdiction, the risk that the data from our clinical trials is not sufficient to the satisfaction of the FDA or comparable foreign regulatory authorities to support the submission of a biologics license application or other comparable submission or to obtain regulatory approval for our product candidates for which we seek approval in the U.S. or elsewhere, and the risk that any such approval may be for a more narrow indication than the Company seeks; the Company’s dependence on the services of the Company’s senior management and other clinical and scientific personnel, and the Company’s ability to retain these individuals or recruit additional management or clinical and scientific personnel; the Company’s ability to grow the Company’s organization, and manage the Company’s growth and expansion of the Company’s operations; risks related to the manufacturing of the Company’s product candidates, which is complex, and the risk that the Company’s third-party manufacturers may encounter difficulties in production; the Company’s ability to obtain and maintain sufficient intellectual property protection for the Company’s product candidates or any future product candidates the Company may develop; the Company’s reliance on third parties to conduct the Company’s preclinical studies and clinical trials; the Company’s compliance with the Company’s obligations under the licenses granted to the Company by others, for the rights to develop and commercialize the Company’s product candidates; significant political, trade, regulatory developments, including changes in relations between the U.S. and China; risks related to the operations of the Company’s suppliers, many of which are located outside of the United States, including the Company’s current sole contract manufacturing organization for obexelimab drug substance and drug product, WuXi Biologics (Hong Kong) Limited, and our partner, InnoCare, both of which are located in China; and other risks and uncertainties described in the section “Risk Factors” in the Company’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2025, as well as other information we file with the Securities and Exchange Commission. The forward-looking statements in this press release are inherently uncertain, speak only as of the date of this press release and may prove incorrect. These statements are based upon information available to the Company as of the date of this press release and while the Company believes such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that the Company has conducted an exhaustive inquiry into, or review of, all potentially available relevant information. Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified and some of which are beyond the Company’s control, these forward-looking statements should not be relied upon as guarantees of future events. The events and circumstances reflected in the forward-looking statements may not be achieved or occur and actual future results, levels of activity, performance and events and circumstances could differ materially from those projected in the forward-looking statements. Moreover, the Company operates in an evolving environment. New risks and uncertainties may emerge from time to time, and management cannot predict all risks and uncertainties. Except as required by applicable law, the Company does not undertake to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events, changed circumstances or otherwise. The Zenas BioPharma word mark, logo mark, and the “lightning bolt” design are trademarks of Zenas BioPharma, Inc. or its affiliated companies. Investor and Media Contact: Argot Partners [email protected]

- Obexelimab Phase 3 INDIGO trial topline results in Immunoglobulin G4-Related Disease (IgG4-RD) expected around year-end 2025 - - Reported highly positive 12-week primary endpoint results from Phase 2 MoonStone trial of obexelimab in Relapsing MS (RMS) - - Secured development and commercialization rights for three autoimmune product candidates, including orelabrutinib, a BTK Inhibitor in Phase 3 development for progressive forms of Multiple Sclerosis (MS) - - Entered into obexelimab funding agreement with Royalty Pharma for up to $300.0 million, including $75M upfront, to support clinical development and potential commercial launch - WALTHAM, Mass., Nov. 12, 2025 (GLOBE NEWSWIRE) -- Zenas BioPharma, Inc. (“Zenas” or the “Company”) (Nasdaq: ZBIO), a clinical-stage global biopharmaceutical company committed to being a leader in the development and commercialization of transformative therapies for patients living with autoimmune diseases, today reported financial results for the third quarter ended September 30, 2025, and provided recent corporate updates. “Our recent achievements mark a significant step toward our vision of becoming a fully integrated, global development and commercial-stage biopharmaceutical company that brings impactful treatments to patients living with autoimmune diseases,” said Lonnie Moulder, Founder and Chief Executive Officer of Zenas. “The outstanding results from our Phase 2 MoonStone trial in relapsing multiple sclerosis validates the rapid, deep and sustained inhibitory mechanism of obexelimab and provide strong evidence of its potential to broadly address the pathogenic role of B cells in autoimmune conditions. In addition, we significantly expanded our pipeline with the in-licensing of three potentially best-in-class product candidates, including orelabrutinib which we are advancing in a Phase 3 progressive multiple sclerosis program, and recently completed two financing transactions. We look forward to sharing topline results from the obexelimab Phase 3 INDIGO trial in IgG4-RD around year-end.” Recent corporate highlights Poised to report Phase 3 data for Obexelimab in Immunoglobulin G4-Related Disease (IgG4-RD): Plan to report topline data from the Phase 3 INDIGO trial, a global registration-directed, multicenter, randomized, double-blind, placebo-controlled trial, to evaluate the efficacy and safety of obexelimab in patients with IgG4-RD around year-end 2025. INDIGO is the largest clinical trial conducted in patients living with IgG4-RD to date. Relapsing Multiple Sclerosis (RMS) Results for Obexelimab: Announced highly positive results from the Phase 2 MoonStone trial of obexelimab in RMS. Obexelimab met the primary endpoint, demonstrating a highly statistically significant 95% relative reduction in the cumulative number of new gadolinium (Gd)-enhancing (GdE) T1 hyperintense lesions over week 8 and week 12 compared with placebo (p=0.0009). The safety profile of obexelimab was consistent with that observed in prior completed trials, including cases of infections and hypersensitivity, most commonly mild injection site reactions. Zenas expects to report 24-week data from the MoonStone trial in the first quarter of 2026. Transformational License Agreement Granting Zenas Rights to Orelabrutinib, a Potential Progressive Multiple Sclerosis (MS) Franchise: Announced a transformational license agreement with InnoCare Pharma Limited (InnoCare) granting Zenas global development and commercialization rights to orelabrutinib, a highly selective CNS-penetrant, oral, small molecule Bruton’s Tyrosine Kinase (BTK) inhibitor with best-in-class potential, in the field of MS and across all therapeutic areas other than oncology in all territories outside Greater China and Southeast Asia. Zenas also secured rights to a novel, oral, potentially best-in-class, IL-17AA/AF inhibitor, and an oral, brain-penetrant, potentially best-in-class, TYK2 inhibitor. In conjunction with the licensing agreement, Zenas announced a private placement financing raising gross proceeds of $120.0 million. The private placement included participation from a syndicate of new and existing investors, including mutual funds and healthcare dedicated funds. Obexelimab Funding Agreement with Royalty Pharma for Up to $300.0 Million: Under the agreement Zenas is eligible to receive up to an aggregate of $300 million, consisting of an upfront payment of $75 million and three additional payments of $75 million each upon (1) achievement of defined success criteria in the Phase 3 INDIGO trial of obexelimab in IgG4-RD, (2) U.S. FDA approval of obexelimab for IgG4-RD, and (3) U.S. FDA approval of obexelimab for systemic lupus erythematosus (SLE). In exchange, Royalty Pharma will receive a 5.5% royalty on worldwide net sales of obexelimab by Zenas and its affiliates and certain other payments associated with the commercialization of obexelimab in partnered geographies. Orelabrutinib Phase 3 Trial in Primary Progressive Multiple Sclerosis (PPMS): Initiated a Phase 3, global registration-directed, multicenter, randomized, double-blind, placebo-controlled trial to evaluate the efficacy and safety of orelabrutinib in patients with PPMS in the third quarter of 2025. Planned Orelabrutinib Phase 3 Trial in Secondary Progressive Multiple Sclerosis (SPMS): A Phase 3, global registration-directed, multicenter, randomized, double-blind, placebo-controlled trial to evaluate the efficacy and safety of orelabrutinib in patients with SPMS is expected to initiate in the first quarter of 2026. Other pipeline updates Obexelimab, a CD19 and FcγRIIb inhibitor of B cell function Systemic Lupus Erythematosus (SLE): Continued enrollment in the Phase 2 SunStone trial, a multicenter, randomized, double-blind, placebo-controlled trial to evaluate the efficacy and safety of obexelimab in patients with SLE. Zenas expects to complete enrollment of the Phase 2 SunStone trial around year-end 2025 and report topline results in mid-2026. ZB021, a novel oral, IL-17AA/AF inhibitor that blocks IL-17 AA homodimer and IL-17AF heterodimer signaling with best-in-class potential In Investigational New Drug (IND) enabling studies: Zenas expects to submit an IND and initiate Phase 1 clinical development in 2026. Pending Phase 1 data, Zenas expects to advance development of ZB021 for rheumatic and/or dermatologic diseases. ZB022, an oral, brain-penetrant, TYK2 inhibitor with best-in-class potential In Investigational New Drug (IND) enabling studies: Zenas expects to submit an IND and initiate Phase 1 clinical development in 2026. Pending Phase 1 data, Zenas expects to advance development of ZB022 for neurologic diseases. Third quarter 2025 financial results As of September 30, 2025, the Company’s cash, cash equivalents and investments were $301.6 million. The Company expects that its cash, cash equivalents and investments, as of September 30, 2025, combined with gross proceeds of $120.0 million from a private placement financing completed in October 2025, will fund its operating expenses and capital expenditure requirements into the fourth quarter of 2026. Assuming receipt of the potential $75 million milestone from Royalty Pharma associated with achieving defined success criteria in the Phase 3 INDIGO trial, the Company expects that its cash, cash equivalents and investments will fund its operating expenses and capital expenditure requirements into the first quarter of 2027. Research and development (R&D) expenses were $34.4 million for the quarter ended September 30, 2025, compared to $33.5 million for the quarter ended September 30, 2024. General and administrative (G&A) expenses were $13.2 million for the quarter ended September 30, 2025, compared to $7.5 million for the quarter ended September 30, 2024. The increase of $5.7 million in G&A expenses was due to an increase in personnel costs, including stock-based compensation expense, pre-commercialization activities, and other expenses associated with operating as a public company. Acquired in-process research and development (AIPR&D) expenses were $5.0 million for the quarter ended September 30, 2025 and related to a deposit paid toward the $35.0 million upfront payment for the exclusive rights to develop and manufacture product candidates under the license agreement with InnoCare. The Company did not recognize AIPR&D expense for the quarter ended September 30, 2024. Net loss was $51.5 million for the quarter ended September 30, 2025, compared to net loss of $38.6 million for the quarter ended September 30, 2024. About Obexelimab Obexelimab is a bifunctional monoclonal antibody designed to bind both CD19 and FcγRIIb, which are broadly present across B cell lineage, to inhibit the activity of cells that are implicated in many autoimmune diseases without depleting them. This unique mechanism of action and self-administered, subcutaneous injection regimen may broadly and effectively address the pathogenic role of the B cell lineage in chronic autoimmune disease. Obexelimab has been evaluated in seven clinical trials, including MoonStone, in a total of 286 subjects who received obexelimab either as an intravenous infusion or as a subcutaneous injection. Obexelimab was well tolerated and demonstrated clinical activity across these clinical trials. Zenas is conducting a fully enrolled Phase 3 trial in Immunoglobulin G4-Related Disease and Phase 2 trials for Relapsing Multiple Sclerosis and Systemic Lupus Erythematosus. About Orelabrutinib Orelabrutinib is a late-stage, potentially best-in-class, highly selective CNS-penetrant, oral, small molecule Bruton’s Tyrosine Kinase (BTK) inhibitor. In Multiple Sclerosis (MS), Zenas is advancing a Phase 3 trial in Primary Progressive MS (PPMS). A Phase 3 trial in Secondary Progressive MS (SPMS) is expected to initiate in the first quarter of 2026. Orelabrutinib is approved for B cell malignancies in mainland China and Singapore, marketed by our partner InnoCare. About Zenas BioPharma, Inc. Zenas is a clinical-stage global biopharmaceutical company committed to becoming a leader in the development and commercialization of transformative therapies for patients living with autoimmune diseases. Our core business strategy combines our experienced leadership team with a disciplined product candidate acquisition approach to identify, acquire and develop product candidates globally that we believe can provide superior clinical benefits to patients living with autoimmune diseases. Zenas is advancing two late-stage, potential franchise molecules, obexelimab and orelabrutinib. Obexelimab, Zenas’ lead product candidate, is a bifunctional monoclonal antibody designed to bind both CD19 and FcγRIIb, which are broadly present across B cell lineage, to inhibit the activity of cells that are implicated in many autoimmune diseases without depleting them. We believe that obexelimab’s unique mechanism of action and self-administered, subcutaneous injection regimen may broadly and effectively address the pathogenic role of B cell lineage in chronic autoimmune disease. Orelabrutinib is a potentially best-in-class, highly selective CNS-penetrant, oral, small molecule BTK inhibitor. Orelabrutinib’s mechanism of action targets pathogenic B cells not only in the periphery but also within the CNS. Additionally, orelabrutinib directly modulates macrophages and microglial cells in the CNS, with the potential to address compartmentalized inflammation and disease progression in MS. Zenas’ earlier stage programs include a potentially best-in-class, oral, IL-17AA/AF inhibitor, and a potentially best-in-class, oral, brain-penetrant, TYK2 inhibitor, both in IND enabling studies. For more information about Zenas BioPharma, please visit https://zenasbio.com/ and follow us on LinkedIn. Forward looking statements This press release contains “forward-looking statements” which involve risks, uncertainties and contingencies, many of which are beyond the control of the Company, which may cause actual results, performance, or achievements to differ materially from anticipated results, performance, or achievements. All statements other than statements of historical facts contained in this press release are forward-looking statements. In some cases, forward-looking statements can be identified by terms such as “may,” “will,” “should,” “expect,” “plan,” “anticipate,” “could,” “intend,” “target,” “project,” “contemplate,” “believe,” “estimate,” “predict,” “potential” or “continue” or the negative of these terms or other similar expressions, although not all forward-looking statements contain these words. Forward-looking statements include, but are not limited to, statements concerning Zenas’ milestones, expectations and intentions, including the potential for obexelimab to become a meaningful therapy across multiple autoimmune diseases and to address the pathogenic role of B cells in autoimmune diseases, the timing of the initiation of, results and data from clinical trials, including timing of reporting topline results from the INDIGO trial, the timing of reporting 24-week topline results from the MoonStone trial, the timing of completing enrollment in and the reporting the topline results from the SunStone trial, the timing of initiation of the Phase 3 clinical trial of orelabrutinib in SPMS, the timing to submit an IND and initiate clinical development in ZB021 and ZB022 as well as the timing and proposed therapeutic areas for ZB021 and ZB022; the potential benefits, development and commercialization of orelabrutinib and obexelimab; the expansion of the Zenas pipeline and cash guidance, including assuming receipt of the potential $75 million milestone from Royalty Pharma associated with achieving defined success criteria in the Phase 3 INDIGO trial. The forward-looking statements in this press release speak only as of the date of this press release and are subject to a number of known and unknown risks, uncertainties and assumptions that could cause the Company’s actual results to differ materially from those anticipated in the forward-looking statements, including, but not limited to: the Company’s limited operating history, incurrence of substantial losses since the Company’s inception and anticipation of incurring substantial and increasing losses for the foreseeable future; the Company’s need for substantial additional financing to achieve the Company’s goals; the uncertainty of clinical development, which is lengthy and expensive, and characterized by uncertain outcomes, and risks related to additional costs or delays in completing, or failing to complete, the development and commercialization of the Company’s current product candidates or any future product candidates; delays or difficulties in the enrollment and dosing of patients in clinical trials; the impact of any significant adverse events or undesirable side effects caused by the Company’s product candidates; potential competition, including from large and specialty pharmaceutical and biotechnology companies, many of which already have approved therapies in the Company’s current indications; the Company’s ability to realize the benefits of the Company’s current or future collaborations or licensing arrangements and ability to successfully consummate future partnerships; the Company’s ability to obtain regulatory approval to commercialize any product candidate in the United States or any other jurisdiction, the risk that the data from our clinical trials is not sufficient to the satisfaction of the FDA or comparable foreign regulatory authorities to support the submission of a biologics license application or other comparable submission or to obtain regulatory approval for our product candidates for which we seek approval in the U.S. or elsewhere, and the risk that any such approval may be for a more narrow indication than the Company seeks; the Company’s dependence on the services of the Company’s senior management and other clinical and scientific personnel, and the Company’s ability to retain these individuals or recruit additional management or clinical and scientific personnel; the Company’s ability to grow the Company’s organization, and manage the Company’s growth and expansion of the Company’s operations; risks related to the manufacturing of the Company’s product candidates, which is complex, and the risk that the Company’s third-party manufacturers may encounter difficulties in production; the Company’s ability to obtain and maintain sufficient intellectual property protection for the Company’s product candidates or any future product candidates the Company may develop; the Company’s reliance on third parties to conduct the Company’s preclinical studies and clinical trials; the Company’s compliance with the Company’s obligations under the licenses granted to the Company by others, for the rights to develop and commercialize the Company’s product candidates; significant political, trade, regulatory developments, including changes in relations between the U.S. and China; risks related to the operations of the Company’s suppliers, many of which are located outside of the United States, including the Company’s current single source contract manufacturing organizations for drug substance and drug product, WuXi Biologics (Hong Kong) Limited, and InnoCare, both of which are located in China; and other risks and uncertainties described in the section “Risk Factors” in the Company’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2025, as well as other information we file with the Securities and Exchange Commission. The forward-looking statements in this press release are inherently uncertain, speak only as of the date of this press release and may prove incorrect. These statements are based upon information available to the Company as of the date of this press release and while the Company believes such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that the Company has conducted an exhaustive inquiry into, or review of, all potentially available relevant information. Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified and some of which are beyond the Company’s control, these forward-looking statements should not be relied upon as guarantees of future events. The events and circumstances reflected in the forward-looking statements may not be achieved or occur and actual future results, levels of activity, performance and events and circumstances could differ materially from those projected in the forward-looking statements. Moreover, the Company operates in an evolving environment. New risks and uncertainties may emerge from time to time, and management cannot predict all risks and uncertainties. Except as required by applicable law, the Company does not undertake to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events, changed circumstances or otherwise. The Zenas BioPharma word mark, logo mark, and the “lightning bolt” design are trademarks of Zenas BioPharma, Inc. or its affiliated companies. Investor and Media Contact: Argot Partners [email protected]

This story was originally published on BioPharma Dive. To receive daily news and insights, subscribe to our free daily BioPharma Dive newsletter. Today, a brief rundown of news from Incyte and Zenas BioPharma, as well as updates from MapLight Therapeutics, Merck & Co. and GSK that you may have missed. Incyte has paused further development of three prospects as part of an ongoing R&D review that will see the company focus on “high-value programs” to drive its “next phase of growth,” CEO Bill Meury said in a quarterly earnings statement Tuesday. In the pipeline reshuffling, Incyte will no longer work on a drug called povorcitinib in a form of chronic urticarias. It’ll also stop testing two other medicines code-named INCA034460 and INCB57643, which the company was evaluating in vitiligo and myelofibrosis, respectively. The moves come amid a heightened focus on Incyte’s pipeline, as the main patent protecting its top-selling drug Jakafi will expire later this decade. — Ben Fidler Shares of Zenas Biopharma climbed by about a third on Monday after the company reported positive results from a Phase 2 study in people with relapsing forms of multiple sclerosis. Zenas said that, when compared to a placebo, its drug obeleximab was associated with a 95% relative reduction, after 8 or 12 weeks, in the cumulative number of new “T1” brain lesions — a sign of active inflammation in MS. The findings were “best-in-disease” data that matched or surpassed what’s been observed in testing of drugs like Ocrevus and Kesimpta, wrote Jefferies analyst Roger Song. Zenas will report longer-term data from the study next year, by which time the company expects to have revealed Phase 3 results from a study of obeleximab in IgG4-disease, another inflammatory condition. — Ben Fidler MapLight Therapeutics raised $251 million in an initial public offering it priced with the help of a little-used regulatory workaround enabling it to debut on Wall Street during the ongoing federal government shutdown. MapLight, which is developing a rival schizophrenia drug to Bristol Myers Squibb’s Cobenfy, sold 14,750,000 shares at $17 apiece in the offering. It also raised about $8 million in a concurrent private share sale to affiliates of Goldman Sachs. The company’s IPO is the third largest this year, only trailing new stock offerings from Metsera in January and LB Pharmaceuticals in September, according to BioPharma Dive data. — Ben Fidler The Food and Drug Administration has approved a broader label for Merck & Co.’s pulmonary arterial hypertension drug Winrevair, the company said Monday. The latest nod clears Winrevair as a treatment to improve exercise capacity, reduce disease severity and lower the risk of serious events such as lung transplants or death in people who are very ill. The approval was based on a trial called Zenith, in which Winrevair reduced the risk of these events 76% when compared to a placebo, in people whose disease is characterized “class III” or “class IV.” In those scenarios. breathlessness limits or precludes physical activity. Winrevair was its initially approved on a data showing it improved the walking speed of people with class II or III disease.— Jonathan Gardner GSK said Monday it acquired worldwide rights to an antibody drug conjugate from the French biotechnology company Syndivia. The deal hands GSK a drug it intends to develop for metastatic castration-resistant prostate cancer. In a statement, GSK claimed the treatment could have a “best-in-class” profile, as preclinical testing suggested it could shrink tumors without causing “a proportional increase in significant side effects, even at higher doses.” Syndivia could receive £268 million, or about $357 million overall, though the companies didn’t disclose how much of that total is in guaranteed upfront cash. — Delilah Alvarado Recommended Reading 3 more biotechs announce layoffs as industry cost-cutting continues

- Obexelimab met primary endpoint with a 95% relative reduction in new gadolinium (Gd)-enhancing T1 lesions compared with placebo, p=0.0009 - WALTHAM, Mass., Oct. 27, 2025 (GLOBE NEWSWIRE) -- Zenas BioPharma, Inc. (“Zenas,” “Zenas BioPharma” or the “Company”) (Nasdaq: ZBIO), a clinical-stage global biopharmaceutical company committed to being a leader in the development and commercialization of transformative therapies for patients living with autoimmune diseases, today announced positive results from the Phase 2 MoonStone trial of obexelimab in Relapsing Multiple Sclerosis (RMS). Obexelimab met the primary endpoint, demonstrating a highly statistically significant 95% relative reduction in the cumulative number of new gadolinium (Gd)-enhancing (GdE) T1 hyperintense lesions over week 8 and week 12 compared with placebo (p=0.0009). “These profound MoonStone trial results, including the near elimination of new GdE T1 lesions, provide strong evidence of the deep and sustained inhibitory mechanism of obexelimab and further validate the potential for obexelimab to become a meaningful therapy across multiple autoimmune diseases, including Immunoglobulin G4-Related Disease and Systemic Lupus Erythematosus, which are currently being evaluated by Zenas in Phase 3 and Phase 2 clinical trials,” said Lonnie Moulder, Founder and Chief Executive Officer of Zenas. Near-complete suppression of new GdE T1 hyperintense lesions, which are markers of active inflammation, was observed with obexelimab by 8 weeks of treatment and was sustained through week 12. The adjusted mean number of new GdE T1 hyperintense lesions per scan in the obexelimab group was 0.01 (95% CI: 0.00, 0.06) compared to 0.23 (95% CI: 0.11, 0.51) with placebo. Additionally, over weeks 8 and 12 of treatment, obexelimab significantly reduced the cumulative number of new and/or enlarging T2 weighted hyperintense lesions compared to placebo, which represent the amount of disease burden or chronic lesion load. The safety profile of obexelimab was consistent with that observed in prior completed trials, including cases of infections and hypersensitivity, most commonly mild injection site reactions. “The observed clinical activity in the MoonStone trial, combined with obexelimab’s unique inhibitory mechanism of action, subcutaneous self-administration and tolerability profile, position obexelimab as a potential option to broadly address the pathogenic role of B cells in autoimmune diseases,” said Lisa von Moltke, M.D., Head of Research and Development and Chief Medical Officer of Zenas. “With these highly statistically significant data, we look forward to reporting 24-week data in the first quarter of 2026, which will include additional secondary and exploratory endpoints that may inform obexelimab’s potential impact on disability progression and help us determine next steps for future development of obexelimab in relapsing MS.” Zenas also expects to report topline results from the obexelimab Phase 3 INDIGO trial in IgG4-RD around year-end 2025 and topline results from the Phase 2 SunStone trial in Systemic Lupus Erythematosus (SLE), mid-2026, as well as the 24-week MoonStone trial results in the first quarter of 2026. In addition, orelabrutinib, a potentially best-in-class, highly-selective central nervous system (CNS)-penetrant, oral, small molecule Bruton’s Tyrosine Kinase (BTK) inhibitor, which Zenas recently in-licensed from InnoCare Pharma Limited, is now being studied in a global Phase 3 clinical trial in patients with Primary Progressive Multiple Sclerosis (PPMS). Zenas also expects to initiate a global Phase 3 trial of orelabrutinib in patients with Secondary Progressive Multiple Sclerosis (SPMS) in the first quarter of 2026. About Multiple Sclerosis Multiple Sclerosis (MS) is a chronic, autoimmune-mediated disorder of the CNS. According to the Multiple Sclerosis International Federation, approximately 2.9 million people worldwide are currently living with MS. The disease disproportionately affects females, and its highest prevalence is observed in North America, Europe and Australia. MS develops when the immune system aberrantly targets the myelin sheath – the protective insulation surrounding axons in the brain, spinal cord and optic nerves – leading to inflammation, demyelination and axonal injury. This pathological cascade disrupts neuronal signal transmission and results in a heterogeneous range of clinical manifestations, including motor weakness, fatigue, and cognitive and visual disturbances. Over time, progressive neurodegeneration contributes to irreversible disability progression. MS onset typically occurs between 20 and 40 years of age, making MS the leading cause of non-traumatic neurological disability in young adults. MS is categorized into three main subtypes, RMS, SPMS and PPMS; all three subtypes are associated with ongoing neuroaxonal loss from the earliest stages of the disease, even in the absence of overt clinical progression. Delays in diagnosis and treatment accelerate disability accumulation, reduce quality of life and increase socioeconomic burden. Consequently, early intervention with highly effective therapies is a key objective in disease management to slow or halt inflammatory and neurodegenerative processes and stop disability progression. RMS is characterized by distinct episodes of new or worsening neurological symptoms (relapses), followed by partial or complete remission. Approximately 85% of patients are initially diagnosed with RMS. Approximately 20-30% of treated RMS patients transition to SPMS, defined by continuous disability progression with or without relapses. Currently, there are no approved therapies for non-relapsing SPMS. PPMS represents 10-15% of all MS diagnoses and is characterized by a steady increase in disability without relapses from disease onset. Currently there is only one approved therapy for PPMS. About the Phase 2 MoonStone Trial The Phase 2 MoonStone trial, which enrolled 116 patients, is a randomized, double-blind, placebo-controlled trial, to evaluate the efficacy and safety of obexelimab in patients with RMS. The trial follows a standard design using magnetic resonance imaging (MRI) endpoints that have historically been highly predictive of successful outcome in large, randomized trials using an endpoint of annualized relapse rate in an RMS study population. After an initial screening period, patients were randomized 2:1 to receive either 250 mg of obexelimab or placebo via subcutaneous injection once weekly over a 12-week double-blinded treatment period. The primary endpoint is the cumulative number of new Gd-enhancing T1 hyperintense lesions over week 8 and week 12 as measured by brain MRI. Secondary and exploratory endpoints include using standardized assessments, imaging, and biomarkers to evaluate the impact on disease progression. Upon completion of the double-blinded phase, all patients enter a 12-week open-label period in which those previously on placebo transition to obexelimab treatment, while those originally assigned to obexelimab continue therapy. During this open-label period, secondary and exploratory endpoints will assess obexelimab’s clinical activity through week 24. About Obexelimab Obexelimab is a bifunctional monoclonal antibody designed to bind both CD19 and FcγRIIb, which are broadly present across B cell lineage, to inhibit the activity of cells that are implicated in many autoimmune diseases without depleting them. This unique mechanism of action and self-administered, subcutaneous injection regimen may broadly and effectively address the pathogenic role of the B cell lineage in chronic autoimmune disease. Obexelimab has been evaluated in seven clinical trials in a total of 286 patients, including MoonStone, who received obexelimab either as an intravenous infusion or as a subcutaneous injection. Obexelimab was well tolerated and demonstrated clinical activity across these clinical trials. Zenas is conducting a fully enrolled Phase 3 trial in Immunoglobulin G4-Related Disease and Phase 2 trials for Relapsing Multiple Sclerosis and Systemic Lupus Erythematosus. About Zenas BioPharma, Inc. Zenas is a clinical-stage global biopharmaceutical company committed to becoming a leader in the development and commercialization of transformative therapies for patients living with autoimmune diseases. Our core business strategy combines our experienced leadership team with a disciplined product candidate acquisition approach to identify, acquire and develop product candidates globally that we believe can provide superior clinical benefits to patients living with autoimmune diseases. Zenas is advancing two late-stage, potential franchise molecules, obexelimab and orelabrutinib. Obexelimab, Zenas’ lead product candidate, is a bifunctional monoclonal antibody designed to bind both CD19 and FcγRIIb, which are broadly present across B cell lineage, to inhibit the activity of cells that are implicated in many autoimmune diseases without depleting them. We believe that obexelimab’s unique mechanism of action and self-administered, subcutaneous injection regimen may broadly and effectively address the pathogenic role of B cell lineage in chronic autoimmune disease. Orelabrutinib is a potentially best-in-class, highly selective CNS-penetrant, oral, small molecule BTK inhibitor. Orelabrutinib’s mechanism of action targets pathogenic B cells not only in the periphery but also within the CNS. Additionally, it directly modulates macrophages and microglial cells in the CNS, with the potential to address compartmentalized inflammation and disease progression in MS. Zenas’ earlier stage programs include a preclinical, potentially best-in-class, oral, IL-17AA/AF inhibitor, and a preclinical, potentially best-in-class, oral, brain-penetrant, TYK2 inhibitor. For more information about Zenas BioPharma, please visit https://zenasbio.com/ and follow us on LinkedIn. Zenas BioPharma Forward-Looking Statements This press release contains “forward-looking statements” which involve risks, uncertainties and contingencies, many of which are beyond the control of the Company, which may cause actual results, performance, or achievements to differ materially from anticipated results, performance, or achievements. All statements other than statements of historical facts contained in this press release are forward-looking statements. In some cases, forward-looking statements can be identified by terms such as “may,” “will,” “should,” “expect,” “plan,” “anticipate,” “could,” “intend,” “target,” “project,” “contemplate,” “believe,” “estimate,” “predict,” “potential” or “continue” or the negative of these terms or other similar expressions, although not all forward-looking statements contain these words. Forward-looking statements include, but are not limited to, statements concerning Zenas’s milestones, expectations and intentions, including the potential for obexelimab to become a meaningful therapy across multiple autoimmune diseases and to address the pathogenic role of B cells in autoimmune diseases, the timing of the initiation of, results and data from clinical trials, including timing of reporting topline results from the INDIGO trial, the timing of reporting 24-week topline results from the MoonStone trial, the timing of the reporting the topline results from the SunStone trial and the timing of initiation of the Phase 3 clinical trial of orelabrutinib in patients with SPMS; the potential benefits, development and commercialization of orelabrutinib and obexelimab; and expansion of the Zenas pipeline. The forward-looking statements in this press release speak only as of the date of this press release and are subject to a number of known and unknown risks, uncertainties and assumptions that could cause the Company’s actual results to differ materially from those anticipated in the forward-looking statements, including, but not limited to: the Company’s limited operating history, incurrence of substantial losses since the Company’s inception and anticipation of incurring substantial and increasing losses for the foreseeable future; the Company’s need for substantial additional financing to achieve the Company’s goals; the uncertainty of clinical development, which is lengthy and expensive, and characterized by uncertain outcomes, and risks related to additional costs or delays in completing, or failing to complete, the development and commercialization of the Company’s current product candidates or any future product candidates; delays or difficulties in the enrollment and dosing of patients in clinical trials; the impact of any significant adverse events or undesirable side effects caused by the Company’s product candidates; potential competition, including from large and specialty pharmaceutical and biotechnology companies, many of which already have approved therapies in the Company’s current indications; the Company’s ability to realize the benefits of the Company’s current or future collaborations or licensing arrangements and ability to successfully consummate future partnerships; the Company’s ability to obtain regulatory approval to commercialize any product candidate in the United States or any other jurisdiction, the risk that the data from our clinical trials is not sufficient to the satisfaction of the FDA or comparable foreign regulatory authorities to support the submission of a biologics license application or other comparable submission or to obtain regulatory approval for our product candidates for which we seek approval in the U.S. or elsewhere, and the risk that any such approval may be for a more narrow indication than the Company seeks; the Company’s dependence on the services of the Company’s senior management and other clinical and scientific personnel, and the Company’s ability to retain these individuals or recruit additional management or clinical and scientific personnel; the Company’s ability to grow the Company’s organization, and manage the Company’s growth and expansion of the Company’s operations; risks related to the manufacturing of the Company’s product candidates, which is complex, and the risk that the Company’s third-party manufacturers may encounter difficulties in production; the Company’s ability to obtain and maintain sufficient intellectual property protection for the Company’s product candidates or any future product candidates the Company may develop; the Company’s reliance on third parties to conduct the Company’s preclinical studies and clinical trials; the Company’s compliance with the Company’s obligations under the licenses granted to the Company by others, for the rights to develop and commercialize the Company’s product candidates; significant political, trade, regulatory developments, including changes in relations between the U.S. and China; risks related to the operations of the Company’s suppliers, many of which are located outside of the United States, including the Company’s current sole contract manufacturing organization for drug substance and drug product, WuXi Biologics (Hong Kong) Limited, which is located in China; and other risks and uncertainties described in the section “Risk Factors” in the Company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2025, as well as other information we file with the Securities and Exchange Commission. The forward-looking statements in this press release are inherently uncertain, speak only as of the date of this press release and may prove incorrect. These statements are based upon information available to the Company as of the date of this press release and while the Company believes such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that the Company has conducted an exhaustive inquiry into, or review of, all potentially available relevant information. Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified and some of which are beyond the Company’s control, these forward-looking statements should not be relied upon as guarantees of future events. The events and circumstances reflected in the forward-looking statements may not be achieved or occur and actual future results, levels of activity, performance and events and circumstances could differ materially from those projected in the forward-looking statements. Moreover, the Company operates in an evolving environment. New risks and uncertainties may emerge from time to time, and management cannot predict all risks and uncertainties. Except as required by applicable law, the Company does not undertake to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events, changed circumstances or otherwise. The Zenas BioPharma word mark, logo mark, and the “lightning bolt” design are trademarks of Zenas BioPharma, Inc. or its affiliated companies. Investor and Media Contact: Argot Partners [email protected]

- Topline results from pivotal Phase 3 INDIGO trial in Immunoglobulin G4-Related Disease expected around year-end 2025 - - Completed enrollment of Phase 2 MoonStone trial in Relapsing Multiple Sclerosis; results expected early in the fourth quarter 2025 - - Enrollment of Phase 2 SunStone trial in Systemic Lupus Erythematosus expected to be completed by year-end 2025; topline results expected mid-2026 - - Cash, cash equivalents and investments of $274.9 million as of June 30, 2025, expected to provide cash runway into the fourth quarter of 2026 - WALTHAM, Mass., Aug. 12, 2025 (GLOBE NEWSWIRE) -- Zenas BioPharma, Inc. (“Zenas” or the “Company”) (Nasdaq: ZBIO), a clinical-stage global biopharmaceutical company committed to being a leader in the development and commercialization of transformative therapies for autoimmune diseases, today reported financial results for the second quarter ended June 30, 2025, and provided recent corporate updates. “We are very pleased with the rapid advancement of our broad obexelimab development program, including the completion of enrollment for the Phase 2 MoonStone trial in patients with Relapsing Multiple Sclerosis this past quarter. We look forward to reporting the results from the primary analysis of the trial, and importantly, the topline results from the Phase 3 INDIGO trial of obexelimab in patients with IgG4-RD,” said Lonnie Moulder, Founder and Chief Executive Officer of Zenas. “Given the differentiated profile of obexelimab, along with our extensive development capabilities and commercialization experience, we are well positioned to execute on the significant opportunity ahead to potentially impact the lives of patients living with autoimmune diseases worldwide.” Recent corporate highlights Obexelimab, a CD-19 x FcγRIIb inhibitor of B cell function Immunoglobulin G4-Related Disease (IgG4-RD): Advanced the Phase 3 INDIGO trial, a global registration-directed, multicenter, randomized, double-blind, placebo-controlled trial, to evaluate the efficacy and safety of obexelimab in patients with IgG4-RD. INDIGO is the largest clinical trial conducted in patients living with IgG4-RD to date. Target enrollment of the INDIGO trial concluded in November 2024, and Zenas expects to report topline results around year-end 2025. Relapsing Multiple Sclerosis (RMS): Completed enrollment of the Phase 2 MoonStone trial, a multicenter, randomized, double-blind, placebo-controlled trial, to evaluate the efficacy and safety of obexelimab in patients with RMS. Zenas expects to report results from this trial, including the 12-week primary endpoint results, early in the fourth quarter of 2025. Systemic Lupus Erythematosus (SLE): Continued enrollment of the Phase 2 SunStone trial, a multicenter, randomized, double-blind, placebo-controlled trial to evaluate the efficacy and safety of obexelimab in patients with SLE. Zenas expects to complete enrollment of the Phase 2 SunStone trial by year-end 2025 and report topline results in mid-2026. Second quarter 2025 financial results As of June 30, 2025, the Company’s cash, cash equivalents and investments were $274.9 million. The Company expects that its cash, cash equivalents and investments, as of June 30, 2025, will fund its operating expenses and capital expenditure requirements into the fourth quarter of 2026. Research and development (R&D) expenses were $43.0 million for the quarter ended June 30, 2025, compared to $33.8 million for the quarter ended June 30, 2024. The increase of $9.2 million in R&D expenses primarily relates to an increase in costs related to the clinical development of obexelimab and an increase in personnel costs partially offset by a decrease in costs related to our partnered programs. General and administrative (G&A) expenses were $12.1 million for the quarter ended June 30, 2025, compared to $5.9 million for the quarter ended June 30, 2024. The increase of $6.2 million in G&A expenses was due to an increase in personnel costs, including stock-based compensation expense, pre-commercialization activities including hiring and other expenses associated with operating as a public company. Net loss was $52.2 million for the quarter ended June 30, 2025, compared to net loss of $38.0 million for the quarter ended June 30, 2024. About Obexelimab Obexelimab is a bifunctional monoclonal antibody designed to bind both CD19 and FcγRIIb, which are broadly present across B cell lineage, to inhibit the activity of cells that are implicated in many autoimmune diseases without depleting them. This unique mechanism of action and self-administered, subcutaneous injection regimen may broadly and effectively address the pathogenic role of B cell lineage in chronic autoimmune disease. Obexelimab has been evaluated in five completed clinical trials in a total of 198 subjects who received obexelimab either as an intravenous infusion or as a subcutaneous injection. Obexelimab was well tolerated and demonstrated pharmacologic activity across these five clinical trials, providing the Company an initial clinical proof of concept for obexelimab as a potent B cell inhibitor for the treatment of patients living with certain autoimmune diseases. Currently, Zenas is conducting multiple Phase 2 and Phase 3 trials of obexelimab in several autoimmune diseases including Immunoglobulin G4-Related Disease, Relapsing Multiple Sclerosis and Systemic Lupus Erythematosus. About Zenas BioPharma, Inc. Zenas is a clinical-stage global biopharmaceutical company committed to becoming a leader in the development and commercialization of transformative therapies for patients with autoimmune diseases. Our core business strategy combines our experienced leadership team with a disciplined product candidate acquisition approach to identify, acquire and develop product candidates globally that we believe can provide superior clinical benefits to patients living with autoimmune diseases. Zenas’ lead product candidate, obexelimab, is a bifunctional monoclonal antibody designed to bind both CD19 and FcγRIIb, which are broadly present across B cell lineage, to inhibit the activity of cells that are implicated in many autoimmune diseases without depleting them. We believe that obexelimab’s unique mechanism of action and self-administered, subcutaneous injection regimen may broadly and effectively address the pathogenic role of B cell lineage in chronic autoimmune disease. For more information about Zenas BioPharma, please visit www.zenasbio.com and follow us on LinkedIn. Forward looking statements This press release contains “forward-looking statements” which involve risks, uncertainties and contingencies, many of which are beyond the control of the Company, which may cause actual results, performance, or achievements to differ materially from anticipated results, performance, or achievements. All statements other than statements of historical facts contained in this press release are forward-looking statements. In some cases, forward-looking statements can be identified by terms such as “may,” “will,” “should,” “expect,” “plan,” “anticipate,” “could,” “intend,” “target,” “project,” “contemplate,” “believe,” “estimate,” “predict,” “potential” or “continue” or the negative of these terms or other similar expressions, although not all forward-looking statements contain these words. Forward-looking statements include, but are not limited to, statements concerning the timing and results of ongoing and future clinical trials, including expectations on the timing of reporting INDIGO trial topline results, results of the 12-week primary endpoint analysis for the MoonStone trial and the anticipated timing of completing enrollment and reporting topline results for the SunStone trial; the ability to potentially impact the treatment of autoimmune diseases; its growth strategy; and cash runway guidance. The forward-looking statements in this press release speak only as of the date of this press release and are subject to a number of known and unknown risks, uncertainties and assumptions that could cause the Company’s actual results to differ materially from those anticipated in the forward-looking statements, including, but not limited to: the Company’s limited operating history, incurrence of substantial losses since the Company’s inception and anticipation of incurring substantial and increasing losses for the foreseeable future; the Company’s need for substantial additional financing to achieve the Company’s goals; the uncertainty of clinical development, which is lengthy and expensive, and characterized by uncertain outcomes, and risks related to additional costs or delays in completing, or failing to complete, the development and commercialization of the Company’s current product candidates or any future product candidates; delays or difficulties in the enrollment and dosing of patients in clinical trials; the impact of any significant adverse events or undesirable side effects caused by the Company’s product candidates; potential competition, including from large and specialty pharmaceutical and biotechnology companies, many of which already have approved therapies in the Company’s current indications; the Company’s ability to realize the benefits of the Company’s current or future collaborations or licensing arrangements and ability to successfully consummate future partnerships; the Company’s ability to obtain regulatory approval to commercialize any product candidate in the United States or any other jurisdiction, and the risk that any such approval may be for a more narrow indication than the Company seeks; the Company’s dependence on the services of the Company’s senior management and other clinical and scientific personnel, and the Company’s ability to retain these individuals or recruit additional management or clinical and scientific personnel; the Company’s ability to grow the Company’s organization, and manage the Company’s growth and expansion of the Company’s operations; risks related to the manufacturing of the Company’s product candidates, which is complex, and the risk that the Company’s third-party manufacturers may encounter difficulties in production; the Company’s ability to obtain and maintain sufficient intellectual property protection for the Company’s product candidates or any future product candidates the Company may develop; the Company’s reliance on third parties to conduct the Company’s preclinical studies and clinical trials; the Company’s compliance with the Company’s obligations under the licenses granted to the Company by others, for the rights to develop and commercialize the Company’s product candidates; significant political, trade, regulatory developments, including changes in relations between the U.S. and China; risks related to the operations of the Company’s suppliers, many of which are located outside of the United States, including the Company’s current sole contract manufacturing organization for drug substance and drug product, WuXi Biologics (Hong Kong) Limited, which is located in China; and other risks and uncertainties described in the section “Risk Factors” in the Company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2025, as well as other information we file with the Securities and Exchange Commission. The forward-looking statements in this press release are inherently uncertain, speak only as of the date of this press release and may prove incorrect. These statements are based upon information available to the Company as of the date of this press release and while the Company believes such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that the Company has conducted an exhaustive inquiry into, or review of, all potentially available relevant information. Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified and some of which are beyond the Company’s control, these forward-looking statements should not be relied upon as guarantees of future events. The events and circumstances reflected in the forward-looking statements may not be achieved or occur and actual future results, levels of activity, performance and events and circumstances could differ materially from those projected in the forward-looking statements. Moreover, the Company operates in an evolving environment. New risks and uncertainties may emerge from time to time, and management cannot predict all risks and uncertainties. Except as required by applicable law, the Company does not undertake to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events, changed circumstances or otherwise. The Zenas BioPharma word mark, logo mark, and the “lightning bolt” design are trademarks of Zenas BioPharma, Inc. or its affiliated companies. Investor and Media Contact: Argot Partners [email protected]

- Topline results from pivotal Phase 3 INDIGO trial in Immunoglobulin G4-Related Disease expected around year-end 2025 - - Phase 2 MoonStone trial in Relapsing Multiple Sclerosis enrollment concluding; topline results expected early in the fourth quarter 2025 - - Enrollment of Phase 2 SunStone trial in Systemic Lupus Erythematosus expected to be completed by year-end 2025; topline results expected mid-2026 - - Strengthened leadership team with appointments of Lisa von Moltke, M.D., Head of Research and Development and Chief Medical Officer, and Haley Laken, Ph.D., Chief Scientific Officer - - Cash, cash equivalents and investments of $314.2 million as of March 31, 2025, expected to provide financial runway into the fourth quarter of 2026 - WALTHAM, Mass., May 15, 2025 (GLOBE NEWSWIRE) -- Zenas BioPharma, Inc. (“Zenas” or the “Company”) (Nasdaq: ZBIO), a clinical-stage global biopharmaceutical company committed to being a leader in the development and commercialization of therapies for autoimmune diseases, today reported financial results for the first quarter ended March 31, 2025, and provided recent corporate updates. “We are pleased with the continued momentum of our obexelimab program across ongoing Phase 2 and Phase 3 clinical trials, for which we expect to report topline results later this year from trials in patients with relapsing multiple sclerosis and IgG4-RD,” said Lonnie Moulder, Founder and Chief Executive Officer of Zenas. “With a strengthened team following the recent additions of Lisa and Haley, we are well positioned to execute on our clinical trials and advance obexelimab as a differentiated B cell inhibitor with a potentially safer, more potent and convenient profile for patients.” Recent corporate highlights Obexelimab, a CD-19 x FcγRIIb inhibitor of B cell function Immunoglobulin G4-Related Disease (IgG4-RD): Advanced the Phase 3 INDIGO trial, a global registration-directed, multicenter, randomized, double-blind, placebo-controlled trial, to evaluate the efficacy and safety of obexelimab in patients with IgG4-RD. INDIGO is the largest clinical trial conducted in patients living with IgG4-RD to date. In the fourth quarter of 2024, Zenas completed the target enrollment of the INDIGO trial and expects to report topline results from the INDIGO trial around year-end 2025. Relapsing Multiple Sclerosis (RMS): Patient screening concluding with the final subject expected to be enrolled in early-June in the Phase 2 MoonStone trial, a multicenter, randomized, double-blind, placebo-controlled trial, to evaluate the efficacy and safety of obexelimab in patients with RMS. The Company expects to report topline results from this trial, including the 12-week primary endpoint results, early in the fourth quarter of 2025. Systemic Lupus Erythematosus (SLE): Continued enrolling in the Phase 2 SunStone trial, a multicenter, randomized, double-blind, placebo-controlled trial to evaluate the efficacy and safety of obexelimab in patients with SLE. Zenas expects to complete enrollment in this trial by year-end 2025 and report topline results in mid-2026. Other corporate highlights Beyond progress with obexelimab, during the first quarter and more recently, the Company: Strengthened its leadership team by appointing Lisa von Moltke, M.D., as Head of Research and Development and Chief Medical Officer, and Haley Laken, Ph.D., as Chief Scientific Officer. Dr. von Moltke brings over 30 years of U.S. and international drug development experience spanning multiple therapeutic areas, including autoimmune diseases, early- and late-stage clinical development, and commercialization at large and emerging growth companies. Dr. Laken brings over 25 years of leadership experience in research, development operations, research and development strategy and business development. Out-licensed regional rights to its thyroid eye disease program, including ZB001, an insulin-like growth factor-1 receptor (anti-IGF-1R) monoclonal antibody, to Zai Lab (Zai). Zenas received an upfront payment and is eligible to receive milestone payments and royalties in the future, as consideration for an exclusive sublicense to Zai to develop and commercialize ZB001 and related programs in Greater China. First quarter 2025 financial results As of March 31, 2025, the Company’s cash, cash equivalents and investments was $314.2 million. The Company expects that its cash, cash equivalents and investments, as of March 31, 2025, will fund its operating expenses and capital expenditure requirements into the fourth quarter of 2026. License and collaboration revenue was $10.0 million for the quarter ended March 31, 2025, related to the one-time non-refundable upfront cash payment received in connection with the sublicense agreement with Zai. The Company did not recognize any license and collaboration revenue during the quarter ended March 31, 2024. Research and development (R&D) expenses were $34.9 million for the quarter ended March 31, 2025, compared to $22.6 million for the quarter ended March 31, 2024. The increase of $12.3 million in R&D expenses primarily relates to an increase in costs related to the clinical development and manufacturing of obexelimab. General and administrative (G&A) expenses were $12.4 million for the quarter ended March 31, 2025, compared to $4.9 million for the quarter ended March 31, 2024. The increase of $7.5 million in G&A expenses was due to an increase in personnel costs, including stock-based compensation expenses, pre-commercialization activities including hiring and other expenses including costs associated with operating as a public company. Net loss was $33.6 million for the quarter ended March 31, 2025, compared to net loss of $27.8 million for the quarter ended March 31, 2024. About Obexelimab Obexelimab is a bifunctional monoclonal antibody designed to bind both CD19 and FcγRIIb, which are broadly present across B cell lineage, to inhibit the activity of cells that are implicated in many autoimmune diseases without depleting them. This unique mechanism of action and self-administered, subcutaneous injection regimen may broadly and effectively address the pathogenic role of B cell lineage in chronic autoimmune disease. Obexelimab has been evaluated in five completed clinical trials in a total of 198 patients who received obexelimab either as an intravenous infusion or as a subcutaneous injection. Obexelimab was well tolerated and demonstrated clinical activity across these five clinical trials, providing the Company an initial clinical proof of concept for obexelimab as a potent B cell inhibitor for the treatment of patients living with certain autoimmune diseases. Currently, Zenas is conducting multiple Phase 2 and Phase 3 trials of obexelimab in several autoimmune diseases including Immunoglobulin G4-Related Disease, Relapsing Multiple Sclerosis and Systemic Lupus Erythematosus. About Zenas BioPharma, Inc. Zenas is a clinical-stage global biopharmaceutical company committed to becoming a leader in the development and commercialization of transformative therapies for patients with autoimmune diseases. Our core business strategy combines our experienced leadership team with a disciplined product candidate acquisition approach to identify, acquire and develop product candidates globally that we believe can provide superior clinical benefits to patients living with autoimmune diseases. Zenas’ lead product candidate, obexelimab, is a bifunctional monoclonal antibody designed to bind both CD19 and FcγRIIb, which are broadly present across B cell lineage, to inhibit the activity of cells that are implicated in many autoimmune diseases without depleting them. We believe that obexelimab’s unique mechanism of action and self-administered, subcutaneous injection regimen may broadly and effectively address the pathogenic role of B cell lineage in chronic autoimmune disease. For more information about Zenas BioPharma, please visit www.zenasbio.com and follow us on LinkedIn. Forward looking statements This press release contains “forward-looking statements” which involve risks, uncertainties and contingencies, many of which are beyond the control of the Company, which may cause actual results, performance, or achievements to differ materially from anticipated results, performance, or achievements. All statements other than statements of historical facts contained in this press release are forward-looking statements. In some cases, forward-looking statements can be identified by terms such as “may,” “will,” “should,” “expect,” “plan,” “anticipate,” “could,” “intend,” “target,” “project,” “contemplate,” “believe,” “estimate,” “predict,” “potential” or “continue” or the negative of these terms or other similar expressions, although not all forward-looking statements contain these words. Forward-looking statements include, but are not limited to, statements concerning the timing and results of ongoing and future clinical trials, including expectations on the timing of reporting INDIGO trial topline results, the last patient to be enrolled in and the 12-week primary endpoint data for the MoonStone trial and the anticipated timing of completing enrollment and reporting topline results for the SunStone trial; its growth strategy; and cash runway guidance. The forward-looking statements in this press release speak only as of the date of this press release and are subject to a number of known and unknown risks, uncertainties and assumptions that could cause the Company’s actual results to differ materially from those anticipated in the forward-looking statements, including, but not limited to: the Company’s limited operating history, incurrence of substantial losses since the Company’s inception and anticipation of incurring substantial and increasing losses for the foreseeable future; the Company’s need for substantial additional financing to achieve the Company’s goals; the uncertainty of clinical development, which is lengthy and expensive, and characterized by uncertain outcomes, and risks related to additional costs or delays in completing, or failing to complete, the development and commercialization of the Company’s current product candidates or any future product candidates; delays or difficulties in the enrollment and dosing of patients in clinical trials; the impact of any significant adverse events or undesirable side effects caused by the Company’s product candidates; potential competition, including from large and specialty pharmaceutical and biotechnology companies, many of which already have approved therapies in the Company’s current indications; the Company’s ability to realize the benefits of the Company’s current or future collaborations or licensing arrangements and ability to successfully consummate future partnerships; the Company’s ability to obtain regulatory approval to commercialize any product candidate in the United States or any other jurisdiction, and the risk that any such approval may be for a more narrow indication than the Company seeks; the Company’s dependence on the services of the Company’s senior management and other clinical and scientific personnel, and the Company’s ability to retain these individuals or recruit additional management or clinical and scientific personnel; the Company’s ability to grow the Company’s organization, and manage the Company’s growth and expansion of the Company’s operations; risks related to the manufacturing of the Company’s product candidates, which is complex, and the risk that the Company’s third-party manufacturers may encounter difficulties in production; the Company’s ability to obtain and maintain sufficient intellectual property protection for the Company’s product candidates or any future product candidates the Company may develop; the Company’s reliance on third parties to conduct the Company’s preclinical studies and clinical trials; the Company’s compliance with the Company’s obligations under the licenses granted to the Company by others, for the rights to develop and commercialize the Company’s product candidates; significant political, trade, regulatory developments, including changes in relations between the U.S. and China; risks related to the operations of the Company’s suppliers, many of which are located outside of the United States, including the Company’s current sole contract manufacturing organization for drug substance and drug product, WuXi Biologics (Hong Kong) Limited, which is located in China; and other risks and uncertainties described in the section “Risk Factors” in the Company’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2025, as well as other information we file with the Securities and Exchange Commission. The forward-looking statements in this press release are inherently uncertain, speak only as of the date of this press release and may prove incorrect. These statements are based upon information available to the Company as of the date of this press release and while the Company believes such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that the Company has conducted an exhaustive inquiry into, or review of, all potentially available relevant information. Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified and some of which are beyond the Company’s control, these forward-looking statements should not be relied upon as guarantees of future events. The events and circumstances reflected in the forward-looking statements may not be achieved or occur and actual future results, levels of activity, performance and events and circumstances could differ materially from those projected in the forward-looking statements. Moreover, the Company operates in an evolving environment. New risks and uncertainties may emerge from time to time, and management cannot predict all risks and uncertainties. Except as required by applicable law, the Company does not undertake to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events, changed circumstances or otherwise. The Zenas BioPharma word mark, logo mark, and the “lightning bolt” design are trademarks of Zenas BioPharma, Inc. or its affiliated companies. Investor and Media Contact: Argot Partners [email protected]