JBIO

~70% IgA reductions sustained at 12 weeks after a single dose of JADE101 >70% IgA reductions projected at steady state with a single subcutaneous maintenance injection every 12 weeks IgA-lowering effect observed to be faster, deeper, and more durable than with first-generation anti-APRIL or dual APRIL/BAFF agents JADE101 was well-tolerated across all evaluated doses Phase 2 clinical trial in patients with IgA nephropathy underway, with interim clinical data expected in 2027 Phase 3 registrational trial expected to be initiated in the first half of 2027 Company to host a webcast and conference call today at 8:00 a.m. ET SAN FRANCISCO and VANCOUVER, British Columbia, June 01, 2026 (GLOBE NEWSWIRE) -- Jade Biosciences, Inc. (the “Company” or “Jade”) (Nasdaq: JBIO), a clinical-stage biotechnology company focused on developing best-in-class therapies for autoimmune diseases, today announced positive interim results from its Phase 1 trial evaluating JADE101, a novel, investigational anti-A Proliferation-Inducing Ligand (APRIL) monoclonal antibody in development for the treatment of immunoglobulin A nephropathy (IgAN). JADE101 is designed with ultra-high binding affinity to selectively block APRIL, a key driver of pathogenic IgA production in IgAN, a chronic autoimmune disease that frequently affects young adults and can lead to end-stage kidney disease over a patient’s lifetime. These results will be presented in a focused oral session during the 63rd European Renal Association (ERA) Congress, taking place in Glasgow, Scotland, from June 3-6, 2026. “IgA is a critical biomarker in IgA nephropathy, with strong evidence linking early and sustained IgA reductions to later reductions in proteinuria, a key marker of disease activity and long-term kidney risk,” said Jonathan Barratt, PhD, Mayer Professor of Renal Medicine at the University of Leicester. “With JADE101, IgA reductions of approximately 70% sustained at 12 weeks in healthy volunteers are both biologically and clinically meaningful, offering the potential to deliver more substantial clinical outcomes and extend the dosing interval beyond currently available therapies. JADE101’s potential to deliver sustained disease control with less frequent dosing could represent a significant advance in treating a disease that often begins in young adulthood and requires lifelong management.” “The interim results from this Phase 1 trial showed that JADE101 drove rapid, deep and durable IgA reductions in healthy volunteers, with favorable tolerability and the potential for dosing every 12 weeks,” said Tom Frohlich, Chief Executive Officer of Jade Biosciences. “JADE101 was designed with ultra-high potency, selective APRIL inhibition and extended half-life to achieve a differentiated and patient-friendly profile. These data position JADE101 as a potentially best-in-class anti-APRIL therapy at the forefront in a large and growing market. With the goal of bringing this therapy to patients as quickly as possible, we have advanced JADE101 into a Phase 2 trial and plan to initiate a Phase 3 registrational trial in the first half of 2027.” JADE101 Phase 1 Trial Design The JADE101 Phase 1 trial is a double-blind, placebo-controlled study evaluating the safety and tolerability, pharmacodynamics (PD) and pharmacokinetics (PK) of single ascending subcutaneously administered doses of JADE101 in healthy volunteers. As of the data cutoff of April 14, 2026, the trial has enrolled 32 healthy adult volunteers across four dose cohorts, with eight participants per cohort randomized in a 6:2 ratio to receive JADE101 or placebo. Evaluated doses included single subcutaneous administrations of 175 mg, 350 mg, 700 mg, and 1,400 mg. Key findings at this interim analysis included: Depth and Duration of IgA Reductions Driven by Potent Free APRIL (fAPRIL) Suppression Mean IgA reductions reached approximately 70% from baseline and were sustained at 12 weeks at the 700 mg dose; this dose is anticipated to reflect the steady-state IgA responses in IgAN patients with the planned JADE101 dosing strategy JADE101 achieved rapid, complete and durable suppression of fAPRIL, consistent with the femtomolar APRIL binding affinity of JADE101 Favorable Safety Profile; Well-Tolerated Across All Evaluated Subcutaneous Dose Levels Single subcutaneous doses of JADE101 up to 1,400 mg were well tolerated with an observed safety profile generally consistent with the anti-APRIL class The most common treatment-emergent adverse events in the pooled safety analysis occurring in more than two participants were headache, upper respiratory tract infection, injection site erythema, oropharyngeal pain and pyrexia There were no serious adverse events and no adverse events leading to study discontinuation There were no cases of hypogammaglobulinemia, defined as IgG less than or equal to 3 g/L Differentiated Pharmacokinetic Profile Supports Potential for Convenient Dosing JADE101 demonstrated dose-dependent increases in exposure across evaluated dose levels Half-life at steady state for JADE101 was approximately 8.7-fold longer than reported for povetacicept and approximately 2.6-fold longer than reported for sibeprenlimab Target-mediated drug disposition threshold with JADE101 is estimated to be approximately 2.5-fold lower than reported for sibeprenlimab No apparent impact of anti-drug antibodies on PK or PD was observed Phase 2 IgAN Trial Underway with Phase 3 Registrational Trial Planned for First Half of 2027 JUNIPER is an ongoing Phase 2 clinical trial evaluating JADE101 in participants with IgAN. The open-label trial is expected to enroll approximately 30 participants. Participants are expected to receive a 700 mg induction dose of JADE101 at treatment onset followed by maintenance doses of 350 mg starting at Week 4 and subsequently either every 8 weeks (n=15) or every 12 weeks (n=15). Evaluating both dose intervals is intended to support accelerated Phase 3 initiation and satisfy global regulatory expectations for dose finding. The primary objectives of the trial are to evaluate the safety and tolerability of JADE101. Secondary and exploratory objectives include changes in 24-hour urine protein-to-creatinine ratio (UPCR-24), including the proportion of participants achieving UPCR-24 levels below 0.5 g/day and 0.3 g/day, renal function as measured by estimated glomerular filtration rate (eGFR), and hematuria resolution over time. Interim clinical data are anticipated in 2027. Jade plans to initiate a registrational Phase 3 clinical trial in the first half of 2027, pending Food and Drug Administration requirements. Conference Call and Webcast Jade Biosciences will host a conference call and webcast on Monday, June 1, 2026, at 8:00 a.m. ET to discuss the JADE101 interim clinical data. Investors and the general public are invited to listen to the live webcast and may register on the “Events and Presentations” page of Jade’s website at JadeBiosciences.com. To join the live conference call, participants must register here. Upon registering, participants will receive dial-in details and a unique PIN to access the call. A replay of the webcast will be available on the Jade website shortly after the call concludes. Jade’s ERA 2026 session details are as follows: Presentation Title: Interim Results of a Phase 1 Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of JADE101 in Healthy Volunteers Presenter: Brandon Gufford, PharmD, PhD, DABCP, Jade Biosciences Session: Glomerular and Tubulo-interstitial DiseasesDate/Time: Friday, June 5, 2026, 2:51 – 2:57 PM BST / 9:51 - 9:57 AM ET Presentation Title: A Phase 2, Multicenter, Open-Label Study to Evaluate the Safety and Efficacy of JADE101 in Participants with Immunoglobulin A Nephropathy  Presenter: Li Li, MD, Jade Biosciences Session: Glomerular and Tubulo-interstitial DiseasesDate/Time: Thursday, June 4, 2026, 5:45 to 5:51 PM BST / 12:45 - 12:51 ET About IgA nephropathy (IgAN) IgAN is a chronic autoimmune kidney disease that affects approximately 169,000 people in the U.S. and is most often diagnosed in young adults. The disease is characterized by the deposition of pathogenic IgA-containing immune complexes in the kidneys. These deposits can lead to increased protein in the urine, also known as proteinuria, declining kidney function, and potentially end-stage kidney disease requiring dialysis or a transplant. IgAN often requires lifelong treatment to preserve kidney function and prevent progression to kidney failure. About Jade Biosciences, Inc.    Jade Biosciences is a clinical-stage biotechnology company focused on developing best-in-class therapies that address critical unmet needs in autoimmune diseases. Jade’s lead candidate, JADE101, targets the cytokine APRIL, and is currently being evaluated for the treatment of immunoglobulin A nephropathy. Jade’s pipeline also includes JADE201, an afucosylated anti-BAFF-R monoclonal antibody, as well as JADE301, an undisclosed antibody program. Jade was launched based on assets licensed from Paragon Therapeutics, an antibody discovery engine founded by Fairmount. For more information, visit JadeBiosciences.com and follow the Company on LinkedIn.    Forward-Looking Statements and Cross-Study Comparisons   Certain statements in this communication, other than purely historical information, may constitute “forward-looking statements” within the meaning of the federal securities laws, including for purposes of the “safe harbor” provisions under the Private Securities Litigation Reform Act of 1995. These forward-looking statements include, but are not limited to, express or implied statements relating to Jade’s expectations, hopes, beliefs, intentions or strategies regarding the future of its pipeline and business including, without limitation: Jade’s ability to achieve the expected benefits or opportunities with respect to JADE101, including its best-in-class potential; the expected enrollment of the Phase 2 clinical trial of JADE101; the expected timelines for the availability of interim data from the Phase 2 clinical trial of JADE101; Jade’s plans to conduct a Phase 3 clinical trial of JADE101, the design and timing thereof and Jade’s expectations that such trial will serve as a registrational study; Jade’s proposed dosing strategy and its expected optimization of clinical activity and convenience; projected or simulated pharmacodynamic outcomes, including steady-state IgA reductions, and the potential therapeutic uses, efficacy, durability, safety profiles, and dosing of JADE101. The words “opportunity,” “potential,” “milestones,” “pipeline,” “can,” “goal,” “strategy,” “target,” “anticipate,” “achieve,” “believe,” “contemplate,” “continue,” “could,” “estimate,” “expect,” “intends,” “may,” “plan,” “possible,” “project,” “should,” “will,” “would” and similar expressions (including the negatives of these terms or variations of them) may identify forward-looking statements, but the absence of these words does not mean that a statement is not forward-looking. These forward-looking statements are based on current expectations and beliefs concerning future developments and their potential effects. There can be no assurance that future developments affecting Jade will be those that have been anticipated. These forward-looking statements involve a number of risks, uncertainties (some of which are beyond Jade’s control) or other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements. These risks and uncertainties include, but are not limited to: interim results of a clinical trial are not necessarily indicative of final results and one or more of the outcomes may materially change following more comprehensive reviews of the data, as follow-up on the outcome of any particular participant continues and as more participant or final data becomes available; modeled and predicted data for JADE101 may not be realized in actual clinical studies and may not accurately represent performance of third party products; the ongoing and planned clinical trials of JADE101 and any other clinical trials may be delayed or may not demonstrate desirable efficacy or predicted performance; Jade’s planned JADE101 Phase 3 clinical trial may be delayed based on FDA feedback or requirements, as the FDA retains broad discretion to require additional clinical data for any product candidate prior to the conduct of a Phase 3 clinical trial or submission for regulatory approval; even if such Phase 3 trial is successful, it may not support regulatory approval; adverse events and safety signals may occur; Jade may experience unanticipated costs, difficulties or delays in the product development process; Jade’s product candidates may be delayed to a point where they are not commercially viable; clinical trial start up, enrollment or regulatory challenges may occur; challenges associated with Jade’s dependence on third-party vendors for the development, manufacture and supply of its product candidates may occur; Jade may use its capital resources sooner than expected; and the other risks, uncertainties and factors more fully described in Jade’s most recent filings with the Securities and Exchange Commission (including the Quarterly Report on Form 10-Q for the quarter ended March 31, 2026). Should one or more of these risks or uncertainties materialize, or should any of Jade’s assumptions prove incorrect, actual results may vary in material respects from those projected in these forward-looking statements. You should not place undue reliance on forward-looking statements in this communication, which speak only as of the date they are made and are qualified in their entirety by reference to the cautionary statements herein. Jade does not undertake or accept any duty to release publicly any updates or revisions to any forward-looking statements. This communication does not purport to summarize all of the conditions, risks and other attributes of an investment in Jade.  No head-to-head study has been conducted comparing JADE101 to other candidates or approved agents. Differences exist between study designs, patient characteristics and other factors, and caution should be exercised in drawing any conclusions from a comparison of the data across studies as cross-study comparisons are inherently limited and such data may not be directly comparable. In addition, data from third party products have been extracted via digitization and represent approximate values.    Jade Biosciences Contact    Priyanka Shah  [email protected]  [email protected]  908-447-6134

SAN FRANCISCO and VANCOUVER, British Columbia, May 29, 2026 (GLOBE NEWSWIRE) -- Jade Biosciences, Inc. (the “Company” or “Jade”) (Nasdaq: JBIO), a clinical-stage biotechnology company focused on developing best-in-class therapies for autoimmune diseases, today announced that it will host a conference call and webcast on Monday, June 1, 2026, at 8:00 a.m. ET to discuss results from the ongoing Phase 1 healthy volunteer study of JADE101. The data are expected to define the dosing strategy and further characterize JADE101’s clinical profile as a potentially differentiated, disease-modifying anti–A Proliferation-Inducing Ligand (APRIL) monoclonal antibody for the treatment of immunoglobulin A nephropathy (IgAN). Conference Call and Webcast Jade Biosciences will host a conference call and webcast on Monday, June 1, 2026, at 8:00 a.m. ET to discuss the JADE101 clinical data. Investors and the general public are invited to listen to the live webcast and may register on the “Events and Presentations” page of the company’s website at JadeBiosciences.com. To join the live conference call, participants must register here. Upon registering, participants will receive dial-in details and a unique PIN to access the call. A replay of the webcast will be available on the Jade website shortly after the call concludes. About IgA nephropathy (IgAN) IgAN is a chronic autoimmune kidney disease that affects approximately 169,000 people in the U.S. and is most often diagnosed in young adults. The disease is characterized by the deposition of pathogenic IgA-containing immune complexes in the kidneys. These deposits can lead to increased protein in the urine, also known as proteinuria, declining kidney function, and potentially end-stage kidney disease requiring dialysis or a transplant. IgAN often requires lifelong treatment to preserve kidney function and prevent progression to kidney failure. About JADE101 JADE101 is a fully human monoclonal antibody that selectively blocks APRIL with ultra-high binding affinity and is engineered for half-life extension. Preclinical studies demonstrated potent, sustained IgA suppression after a single dose in non-human primates, with a serum half-life of approximately 27 days. JADE101 was designed to avoid formation of high molecular weight immune complexes, with the goal of supporting predictable pharmacokinetics and reduced immunogenicity risk. Its differentiated pharmacokinetic and pharmacodynamic profile supports the potential for infrequent and convenient subcutaneous dosing, an important consideration for a condition often diagnosed in young adulthood and potentially requiring life-long treatment. About Jade Biosciences, Inc.      Jade Biosciences is a clinical-stage biotechnology company focused on developing best-in-class therapies that address critical unmet needs in autoimmune diseases. Jade’s lead candidate, JADE101, targets the cytokine APRIL, and is currently being evaluated for the treatment of immunoglobulin A nephropathy. Jade’s pipeline also includes JADE201, an afucosylated anti-BAFF-R monoclonal antibody, as well as JADE301, an undisclosed antibody program. Jade was launched based on assets licensed from Paragon Therapeutics, an antibody discovery engine founded by Fairmount. For more information, visit JadeBiosciences.com and follow the Company on LinkedIn.      Forward-Looking Statements Certain statements in this communication, other than purely historical information, may constitute “forward-looking statements” within the meaning of the federal securities laws, including for purposes of the “safe harbor” provisions under the Private Securities Litigation Reform Act of 1995. These forward-looking statements include, but are not limited to, express or implied statements relating to Jade’s expectations, hopes, beliefs, intentions or strategies regarding the future of its pipeline and business including, without limitation, how the data from the ongoing Phase 1 healthy volunteer study of JADE101 will characterize JADE101’s clinical profile; the expected benefits or opportunities with respect to JADE101; the potential of JADE101 and Jade’s other product candidates to become best-in-class therapies; and the potential therapeutic uses, efficacy, durability, safety profiles, and dosing of JADE101. The words “opportunity,” “potential,” “milestones,” “pipeline,” “can,” “goal,” “strategy,” “target,” “anticipate,” “achieve,” “believe,” “contemplate,” “continue,” “could,” “estimate,” “expect,” “intends,” “may,” “plan,” “possible,” “project,” “should,” “will,” “would” and similar expressions (including the negatives of these terms or variations of them) may identify forward-looking statements, but the absence of these words does not mean that a statement is not forward-looking. These forward-looking statements are based on current expectations and beliefs concerning future developments and their potential effects. There can be no assurance that future developments affecting Jade will be those that have been anticipated. These forward-looking statements involve a number of risks, uncertainties (some of which are beyond Jade’s control) or other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements. These risks and uncertainties include, but are not limited to, the risks that the ongoing and any future clinical trials of JADE101 may be delayed or may not demonstrate desirable efficacy or clinical profile; adverse events and safety signals may occur; Jade’s product candidates may fail in development, may not receive required regulatory approvals, or may be delayed to a point where they are not commercially viable; enrollment or regulatory challenges; and the other risks, uncertainties and factors more fully described in Jade’s most recent filings with the Securities and Exchange Commission (including the Quarterly Report on Form 10-Q for the quarter ended March 31, 2026). Should one or more of these risks or uncertainties materialize, or should any of Jade’s assumptions prove incorrect, actual results may vary in material respects from those projected in these forward-looking statements. You should not place undue reliance on forward-looking statements in this communication, which speak only as of the date they are made and are qualified in their entirety by reference to the cautionary statements herein. Jade does not undertake or accept any duty to release publicly any updates or revisions to any forward-looking statements. This communication does not purport to summarize all of the conditions, risks and other attributes of an investment in Jade. Jade Biosciences Contact     Priyanka Shah   [email protected]   [email protected]   908-447-6134

Interim biomarker-rich Phase 1 data for JADE101 to be featured in an oral session at the 63rd European Renal Association Congress Phase 2 trial of JADE101 in IgA nephropathy patients expected to begin in the second quarter of 2026; interim data expected in 2027 Phase 1 study of JADE201, a half-life extended afucosylated anti-BAFF-R antibody, expected to begin in the second quarter of 2026; interim data expected in 2027 Phase 1 clinical trial for JADE301 remains on track to begin in the first half of 2027 $311 million in cash, cash equivalents, and investments as of March 31, 2026 expected to provide runway into the first half of 2028 SAN FRANCISCO and VANCOUVER, British Columbia, May 07, 2026 (GLOBE NEWSWIRE) -- Jade Biosciences, Inc. (“Jade” or the “Company”) (Nasdaq: JBIO), a biotechnology company focused on developing best-in-class therapies for autoimmune diseases, today announced financial results for the first quarter ending March 31, 2026, and provided a corporate update. “With the upcoming initial biomarker-rich Phase 1 data for our lead program, JADE101, and an additional program expected to enter the clinic this quarter, we are transitioning into a new phase of focused clinical execution,” said Tom Frohlich, Chief Executive Officer of Jade Biosciences. “We believe these milestones position us to generate meaningful clinical insights across our portfolio over the coming quarters, while continuing to rapidly advance our pipeline of potentially best-in-class therapies for autoimmune diseases.” Pipeline and Corporate Updates JADE101: potentially best-in-class selective anti-APRIL monoclonal antibody for IgA nephropathy (IgAN) Biomarker-rich interim data from the Phase 1 healthy volunteer study of JADE101 to be presented in an oral session at the 63rd European Renal Association (ERA) Congress. These data are expected to define the dose and dosing interval for subsequent JADE101 IgAN patient studies and further characterize JADE101’s profile. Following review of the Phase 1 data, Jade expects to evaluate potential opportunities to accelerate the clinical development of JADE101. The company expects to initiate a Phase 2 clinical trial evaluating JADE101 in patients with IgAN in the second quarter of 2026; interim data are expected in 2027. A Trial-in-Progress presentation will be delivered during an oral session at the 2026 ERA Congress. JADE201: potentially best-in-class anti-BAFF-R monoclonal antibody for autoimmune diseases The company expects to initiate a Phase 1 clinical trial evaluating JADE201 in patients with rheumatoid arthritis in the second quarter of 2026. Interim Phase 1 data are expected in 2027 and will inform indication prioritization and a focused clinical development strategy. JADE201 has broad potential across multiple autoimmune indications supported by B cell and BAFF-R biology. JADE301: undisclosed antibody program for autoimmune diseases JADE301, an undisclosed antibody program targeting autoimmune diseases, is expected to enter a first-in-human clinical trial in the first half of 2027. Additional details are expected to be disclosed in the second half of 2026. Corporate Jade appointed Edward R. Conner, M.D., as Chief Medical Officer (CMO). Dr. Conner is an accomplished biopharmaceutical executive with deep experience in clinical development, translational medicine and regulatory strategy across early- and late-stage programs. As CMO, he will lead Jade’s clinical and medical organization and advance the Company’s pipeline of potentially disease-modifying therapies for autoimmune diseases. The company announced the promotion of Dr. Andrew King to President, Research and Development, reflecting his expanded leadership and strategic oversight across the research and development organization. First Quarter 2026 Financial Results Cash Position: As of March 31, 2026, Jade had cash, cash equivalents, and investments of $311.3 million. Based on its current operating plans, Jade believes that its existing cash will enable it to fund its operating expenses and capital expenditure requirements into the first half of 2028. Research and Development (R&D) expenses: R&D expenses totaled $36.1 million for the first quarter ended March 31, 2026, compared to $20.0 million for the quarter ended March 31, 2025. R&D expenses increased primarily due to increased costs around chemistry, manufacturing and controls and clinical activity as well as higher personnel-related costs as the Company builds out the internal R&D function. General and Administrative (G&A) expenses: G&A expenses totaled $7.4 million for the first quarter ended March 31, 2026, compared to $3.4 million for the quarter ended March 31, 2025. G&A expenses increased primarily due to higher personnel-related costs as the Company builds out its internal infrastructure. Net loss: Net loss totaled $40.4 million for the first quarter ended March 31, 2026, compared to $38.2 million for the quarter ended March 31, 2025. Net loss increased primarily due to higher R&D and G&A expenses, as described above. Shares Outstanding: As of March 31, 2026, Jade had approximately 70,745,453 shares of common stock and common stock equivalents outstanding, including shares underlying pre-funded warrants and non-voting convertible preferred stock. About Jade Biosciences, Inc. Jade Biosciences is a clinical-stage biotechnology company focused on developing best-in-class therapies that address critical unmet needs in autoimmune diseases. Jade’s lead candidate, JADE101, targets the cytokine APRIL, and is currently being evaluated for the treatment of immunoglobulin A nephropathy. Jade’s pipeline also includes JADE201, an afucosylated anti-BAFF-R monoclonal antibody, as well as JADE301, an undisclosed antibody candidate. Jade was launched based on assets licensed from Paragon Therapeutics, an antibody discovery engine founded by Fairmount. For more information, visit JadeBiosciences.com and follow the Company on LinkedIn. Forward-Looking Statements Certain statements in this communication, other than purely historical information, may constitute “forward-looking statements” within the meaning of the federal securities laws, including for purposes of the “safe harbor” provisions under the Private Securities Litigation Reform Act of 1995. These forward-looking statements include, but are not limited to, express or implied statements relating to Jade’s expectations, hopes, beliefs, intentions or strategies regarding the future of its pipeline and business including, without limitation: Jade’s ability to achieve the expected benefits or opportunities with respect to JADE101, JADE201 and JADE301; plans for future clinical trials, including the expected timelines for initiation of the Phase 2 clinical trial of JADE 101 and first-in-human clinical trials of JADE201 and JADE301; expected timelines for data from the Phase 1 clinical trial of JADE101, the Phase 2 clinical trial of JADE101 and the Phase 1 clinical trial of JADE201 and the potential to accelerate the clinical development of JADE101; the potential of Jade’s product candidates to become best-in-class therapies; their potential therapeutic uses, efficacy, safety profiles, and dosing; and the potential for Jade’s cash runway to extend into the first half of 2028. The words “opportunity,” “potential,” “milestones,” “pipeline,” “can,” “goal,” “strategy,” “target,” “anticipate,” “achieve,” “believe,” “contemplate,” “continue,” “could,” “estimate,” “expect,” “intends,” “may,” “plan,” “possible,” “project,” “should,” “will,” “would” and similar expressions (including the negatives of these terms or variations of them) may identify forward-looking statements, but the absence of these words does not mean that a statement is not forward-looking. These forward-looking statements are based on current expectations and beliefs concerning future developments and their potential effects. There can be no assurance that future developments affecting Jade will be those that have been anticipated. These forward-looking statements involve a number of risks, uncertainties (some of which are beyond Jade’s control) or other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements. These risks and uncertainties include, but are not limited to: the risks that the Phase 1 clinical trial of JADE101, the planned Phase 2 clinical trial of JADE101, the planned Phase 1 clinical trials of JADE201 and JADE301 and any other future trials may be delayed or may not demonstrate desirable efficacy; adverse events and safety signals may occur; Jade may experience unanticipated costs, difficulties or delays in the product development process; Jade’s product candidates may fail in development, may not receive required regulatory approvals, or may be delayed to a point where they are not commercially viable; enrollment or regulatory challenges; risks associated with Jade’s dependence on third-party vendors for the development, manufacture and supply of its product candidates; Jade may use its capital resources sooner than expected; and the other risks, uncertainties and factors more fully described in Jade’s most recent filings with the Securities and Exchange Commission (including the Annual Report on Form 10-K for the year ended December 31, 2025 and its subsequent filings). Should one or more of these risks or uncertainties materialize, or should any of Jade’s assumptions prove incorrect, actual results may vary in material respects from those projected in these forward-looking statements. You should not place undue reliance on forward-looking statements in this communication, which speak only as of the date they are made and are qualified in their entirety by reference to the cautionary statements herein. Jade does not undertake or accept any duty to release publicly any updates or revisions to any forward-looking statements, except as required by law. This communication does not purport to summarize all of the conditions, risks and other attributes of an investment in Jade. Jade Biosciences Contact Priyanka Shah [email protected] [email protected] 908-447-6134

JADE101 Phase 1 healthy volunteer interim data expected in the second quarter of 2026; Phase 2 clinical trial in patients with IgA nephropathy expected to begin mid-2026 with preliminary data anticipated in 2027 JADE201, a half-life extended afucosylated anti-BAFF receptor antibody, expected to advance into first-in-human clinical trial in rheumatoid arthritis patients in the second quarter of 2026; interim data anticipated in 2027 Third development candidate, JADE301, nominated; Phase 1 clinical trial expected to commence in the first half of 2027 $336 million of cash, cash equivalents, and investments as of December 31st, 2025 expected to provide runway into the first half of 2028 SAN FRANCISCO and VANCOUVER, British Columbia, March 06, 2026 (GLOBE NEWSWIRE) -- Jade Biosciences, Inc. (“Jade” or the “Company”) (Nasdaq: JBIO), a biotechnology company focused on developing best-in-class therapies for autoimmune diseases, today announced financial results for the fourth quarter and full year ending December 31, 2025, and provided a corporate update. Tom Frohlich, Chief Executive Officer of Jade Biosciences, commented: “We closed 2025 with strong momentum, having initiated the JADE101 Phase 1 healthy volunteer study, continued to advance JADE201 toward the clinic, and further strengthened our team and balance sheet. As we look ahead, our focus is on delivering interim, biomarker-rich Phase 1 data for JADE101, initiating the Phase 2 clinical trial in IgA nephropathy, and starting first-in-human dosing for the Phase 1 clinical trial of JADE201. With multiple clinical milestones approaching and cash runway expected to extend into the first half of 2028, we are well positioned to execute on our near-term priorities while continuing to build a differentiated pipeline with the goal of delivering best-in-class, disease-modifying autoimmune therapies to patients.” Pipeline and Corporate Updates JADE101: potentially best-in-class selective anti-APRIL monoclonal antibody for IgA nephropathy (IgAN) Phase 1 biomarker-rich interim results from the ongoing healthy volunteer study are expected in the second quarter of 2026 and are anticipated to define dose and dose interval selection for IgAN patient studies. Jade expects to evaluate the Phase 1 clinical data and explore opportunities to accelerate the development of JADE101. Jade expects to initiate a Phase 2 clinical trial in patients with IgAN mid-2026, with preliminary data anticipated in 2027. JADE201: potentially best-in-class anti-BAFF-R monoclonal antibody for autoimmune diseases A first-in-human study initially evaluating JADE201 in patients with rheumatoid arthritis is expected to begin in the second quarter of 2026, with interim data anticipated in 2027. With its differentiated mechanism and engineering, JADE201 has broad potential across a range of autoimmune diseases validated by BAFF-R biology. JADE301: undisclosed antibody program for autoimmune diseases JADE301, an undisclosed antibody program, is expected to enter a first-in-human clinical trial in the first half of 2027. Further details on JADE301 are expected to be disclosed in the second half of 2026. Corporate In the fourth quarter, Jade completed two private placement financings resulting in gross proceeds of approximately $180 million, with participation from new and existing leading healthcare investors. Fourth Quarter and Full Year 2025 Financial Results Cash Position: As of December 31, 2025, Jade had cash, cash equivalents, and investments of $336.2 million. Based on its current operating plans, Jade believes that its existing cash will enable it to fund its operating expenses and capital expenditure requirements into the first half of 2028. Research and Development (R&D) expenses: R&D expenses totaled $28.5 million for the fourth quarter ended December 31, 2025, compared to $17.6 million for the quarter ended December 31, 2024. For the full year ended December 31, 2025, R&D expenses totaled $93.1 million, compared to $31.2 million for the period from June 18, 2024 (Inception) to December 31, 2024. R&D expenses increased primarily due to higher personnel-related costs as the Company builds out the internal R&D function as well as increased costs around chemistry, manufacturing and controls and early clinical activity. General and Administrative (G&A) expenses: G&A expenses totaled $6.4 million for the fourth quarter ended December 31, 2025, compared to $2.4 million for the quarter ended December 31, 2024. For the full year ended December 31, 2025, G&A expenses totaled $20.4 million, compared to $4.3 million for the period from June 18, 2024 (Inception) to December 31, 2024. G&A expenses increased primarily due to higher personnel-related costs as the Company builds out its internal infrastructure. Net loss: Net loss totaled $31.9 million for the fourth quarter ended December 31, 2025, compared to a net loss of $30.1 million for the quarter ended December 31, 2024. For the full year ended December 31, 2025, net loss was $127.4 million, compared to $47.0 million for the period from June 18, 2024 (Inception) to December 31, 2024. Net loss increased primarily as a result of higher R&D and G&A expenses, as described above. Shares Outstanding: As of December 31, 2025, Jade had approximately 70,715,773 million shares of common stock and common stock equivalents outstanding, including shares underlying pre-funded warrants and non-voting convertible preferred stock. About Jade Biosciences, Inc. Jade Biosciences is a clinical-stage biotechnology company focused on developing best-in-class therapies that address critical unmet needs in autoimmune diseases. Jade’s lead candidate, JADE101, targets the cytokine APRIL, and is currently being evaluated in a Phase 1 clinical trial for the treatment of immunoglobulin A nephropathy. Jade’s pipeline also includes JADE201, an afucosylated anti-BAFF-R monoclonal antibody, as well as JADE301, an undisclosed antibody candidate, both currently in preclinical development. Jade was launched based on assets licensed from Paragon Therapeutics, an antibody discovery engine founded by Fairmount. For more information, visit JadeBiosciences.com and follow the Company on LinkedIn. Forward-Looking Statements Certain statements in this communication, other than purely historical information, may constitute “forward-looking statements” within the meaning of the federal securities laws, including for purposes of the “safe harbor” provisions under the Private Securities Litigation Reform Act of 1995. These forward-looking statements include, but are not limited to, express or implied statements relating to Jade’s expectations, hopes, beliefs, intentions or strategies regarding the future of its pipeline and business including, without limitation, Jade’s ability to achieve the expected benefits or opportunities with respect to JADE101, JADE201 and JADE301; plans for future clinical trials, including the expected timelines for initiation of the Phase 2 clinical trial of JADE 101 and first-in-human clinical trials of JADE201 and JADE301; expected timelines for data from the Phase 1 clinical trial of JADE101, the Phase 2 clinical trial of JADE101 and the Phase 1 clinical trial of JADE201; the potential of Jade’s product candidates to become best-in-class therapies, their potential therapeutic uses, efficacy, safety profiles, and dosing; and the potential for Jade’s cash runway to extend into the first half of 2028. The words “opportunity,” “potential,” “milestones,” “pipeline,” “can,” “goal,” “strategy,” “target,” “anticipate,” “achieve,” “believe,” “contemplate,” “continue,” “could,” “estimate,” “expect,” “intends,” “may,” “plan,” “possible,” “project,” “should,” “will,” “would” and similar expressions (including the negatives of these terms or variations of them) may identify forward-looking statements, but the absence of these words does not mean that a statement is not forward-looking. These forward-looking statements are based on current expectations and beliefs concerning future developments and their potential effects. There can be no assurance that future developments affecting Jade will be those that have been anticipated. These forward-looking statements involve a number of risks, uncertainties (some of which are beyond Jade’s control) or other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements. These risks and uncertainties include, but are not limited to, the risks that the Phase 1 clinical trial of JADE101, the planned Phase 2 clinical trial of JADE101, the planned Phase 1 clinical trials of JADE201 and JADE301 and any other future trials may be delayed or may not demonstrate desirable efficacy; adverse events and safety signals may occur; Jade may experience unanticipated costs, difficulties or delays in the product development process; Jade’s product candidates may fail in development, may not receive required regulatory approvals, or may be delayed to a point where they are not commercially viable; enrollment or regulatory challenges; risks associated with Jade’s dependence on third-party vendors for the development, manufacture and supply of its product candidates; Jade may use its capital resources sooner than expected; and the other risks, uncertainties and factors more fully described in Jade’s most recent filings with the Securities and Exchange Commission (including the Quarterly Report on Form 10-Q for the quarter ended September 30, 2025 and its subsequent filings). Should one or more of these risks or uncertainties materialize, or should any of Jade’s assumptions prove incorrect, actual results may vary in material respects from those projected in these forward-looking statements. You should not place undue reliance on forward-looking statements in this communication, which speak only as of the date they are made and are qualified in their entirety by reference to the cautionary statements herein. Jade does not undertake or accept any duty to release publicly any updates or revisions to any forward-looking statements, except as required by law. This communication does not purport to summarize all of the conditions, risks and other attributes of an investment in Jade. Jade Biosciences Contact Priyanka Shah [email protected] [email protected] 908-447-6134

Presented favorable preclinical safety data for JADE101 and a translational analysis of APRIL mediated biomarker responses at the American Society of Nephrology Kidney Week 2025, reinforcing its potential as a best-in-class selective anti-APRIL monoclonal antibody for IgA nephropathy Initiated Phase 1 healthy volunteer study of JADE101; interim, biomarker-rich data expected in the first half of 2026 are anticipated to define dose and dose interval selection for patient trials Unveiled JADE201, a potentially best-in-class, half-life extended, afucosylated anti-BAFF receptor monoclonal antibody; first-in-human trial in rheumatoid arthritis expected to begin in the first half of 2026 with potential opportunity across multiple autoimmune diseases validated by BAFF-R biology Completed $135 million private placement, extending cash runway into the first half of 2028 SAN FRANCISCO and VANCOUVER, British Columbia, Nov. 13, 2025 (GLOBE NEWSWIRE) -- Jade Biosciences, Inc. (“Jade”) (Nasdaq: JBIO), a biotechnology company focused on developing best-in-class therapies for autoimmune diseases, today announced financial results for the quarter ending September 30, 2025, and provided a corporate update. “The third quarter marked meaningful progress toward our mission of delivering potentially best-in-class therapies for autoimmune diseases,” said Tom Frohlich, Chief Executive Officer of Jade Biosciences. “At the recent ASN Kidney Week, we presented preclinical safety and translational data that support JADE101’s potential to be a best-in-class, selective anti-APRIL therapy and provide further confidence that biomarker data from our ongoing Phase 1 healthy volunteer trial will define the dosing strategy for IgAN patient studies. We also introduced our second development candidate, JADE201, which builds on validated BAFF-R biology to potentially address a broad range of autoimmune diseases, and completed a $135 million private financing. With these achievements, we are well positioned to execute on multiple clinical milestones and bring further innovation in autoimmune disease treatment.” Pipeline and Corporate Updates JADE101: potentially best-in-class selective anti-APRIL monoclonal antibody for IgA nephropathy (IgAN) Presented two posters at the American Society of Nephrology (ASN) Kidney Week 2025. JADE101 is an ultra-high affinity, half-life-extended fully human monoclonal antibody that has the potential for best-in-class activity with convenient patient dosing. JADE101 is an ultra-high affinity, half-life-extended fully human monoclonal antibody that has the potential for best-in-class activity with convenient patient dosing. In a poster presentation of non-clinical safety data, JADE101 was well tolerated in NHPs at all doses tested preclinically, including at the highest dose establishing the no-observed-adverse-effect level (NOAEL), supporting the first-in-human doses being evaluated in the ongoing Phase 1 trial. JADE101 showed no off-target binding, tissue cross-reactivity, or cytokine release and produced reversible, mechanism-consistent reductions in serum immunoglobulins (IgA, IgM, IgG) without evidence of broad immune suppression, reinforcing its potential as a well-tolerated and selective therapy. A second poster presentation described a translational assessment demonstrating consistency of biomarker responses to APRIL inhibition across NHPs, healthy volunteers and IgAN patients, showing that pharmacokinetic and biomarker responses observed in healthy volunteers are predictive of anticipated therapeutic outcomes in IgAN patients. These analyses link the depth and duration of APRIL suppression to expected reductions in IgA, Gd-IgA1, and proteinuria associated with kidney function preservation, supporting that biomarker data from the ongoing Phase 1 study will define dose and dosing interval selection for IgAN patient trials and enable convenient, infrequent subcutaneous dosing. Initiated enrollment in Phase 1 clinical trial evaluating JADE101 administered as a subcutaneous injection in healthy volunteers. Interim, biomarker-rich data are expected in the first half of 2026 and are anticipated to define the dose and dose interval for Phase 2 and Phase 3 clinical trials. JADE201: potentially best-in-class anti-BAFF-R monoclonal antibody for autoimmune diseases Introduced JADE201, a half-life extended, afucosylated monoclonal antibody targeting the B-cell activating factor receptor (BAFF-R). JADE201 is designed to overcome the limitations of current B cell-directed therapies by combining a dual mechanism of action and half-life extension technology, with the goal of improving on the clinical benefit of existing B-cell depleting therapies across a broad range of autoimmune diseases with less frequent subcutaneous dosing. JADE201 builds on the clinical proof-of-concept for BAFF-R targeting established by ianalumab, which met primary endpoints in recent Phase 3 Sjogren’s and idiopathic thrombocytopenic purpura trials. In NHP studies, JADE201 showed high-affinity BAFF-R binding, achieved dose-dependent BAFF receptor occupancy, sustained B-cell depletion, and demonstrated an approximately two-fold extended half-life versus ianalumab. A first-in-human trial evaluating JADE201 in rheumatoid arthritis is expected to begin in the first half of 2026, with potential for broad opportunity across multiple autoimmune diseases validated by BAFF-R biology. Corporate Completed a $135 million private placement with participation from new and existing leading healthcare investors. Third Quarter 2025 Financial Results Cash Position: As of September 30, 2025, Jade had cash, cash equivalents, and investments of $198.9 million. In October, the Company closed on a $135 million private placement financing, resulting in cash, cash equivalents, and investments of approximately $325.6 million on a pro-forma basis as of September 30, 2025. Based on its current operating plans, Jade believes that its existing cash will enable it to fund its operating expenses and capital expenditure requirements into the first half of 2028. Research and Development (R&D) expenses: R&D expenses totaled $22.0 million for the third quarter ended September 30, 2025, compared to $13.6 million for the quarter ended September 30, 2024. R&D expenses increased primarily due to higher personnel-related costs as the Company builds out the internal R&D function as well as increased costs around CMC and early clinical activity. General and Administrative (G&A) expenses: G&A expenses totaled $5.4 million for the third quarter ended September 30, 2025, compared to $1.4 million for the quarter ended September 30, 2024. G&A expenses increased primarily due to higher personnel-related costs as the Company builds out its internal infrastructure. Net loss: Net loss totaled $25.2 million for the third quarter ended September 30, 2025, compared to a net loss of $16.3 million for the quarter ended September 30, 2024. Net loss increased primarily as a result of higher R&D and G&A expenses, as described above. Shares Outstanding: After giving effect to the Company’s recently completed $135 million private placement, Jade had 67,394,380 million shares of the Company’s common stock and common stock equivalents issued and outstanding, including shares of common stock underlying pre-funded warrants and non-voting convertible preferred. About Jade Biosciences, Inc. Jade Biosciences is a clinical-stage biotechnology company focused on developing best-in-class therapies that address critical unmet needs in autoimmune diseases. Jade’s lead candidate, JADE101, targets the cytokine APRIL, and is currently being evaluated in a Phase 1 clinical trial for the treatment of immunoglobulin A nephropathy. Jade’s pipeline also includes JADE201, an afucosylated anti-BAFF-R monoclonal antibody, as well as JADE-003, an undisclosed antibody discovery program, both currently in preclinical development. Jade was launched based on assets licensed from Paragon Therapeutics, an antibody discovery engine founded by Fairmount. For more information, visit JadeBiosciences.com and follow the Company on LinkedIn. Forward-Looking Statements Certain statements in this communication, other than purely historical information, may constitute “forward-looking statements” within the meaning of the federal securities laws, including for purposes of the “safe harbor” provisions under the Private Securities Litigation Reform Act of 1995. These forward-looking statements include, but are not limited to, express or implied statements relating to Jade’s expectations, hopes, beliefs, intentions or strategies regarding the future of its pipeline and business including, without limitation, Jade’s ability to achieve the expected benefits or opportunities with respect to JADE101, JADE201 and JADE-003, the expected timelines for interim data from the Phase 1 clinical trial of JADE101 and for JADE201 entering the clinic, plans for future clinical trials, the potential of Jade’s product candidates to become best-in-class therapies, their potential therapeutic uses, efficacy, safety profiles, and dosing, and the potential for Jade’s cash runway to extend into the first half of 2028. The words “opportunity,” “potential,” “milestones,” “pipeline,” “can,” “goal,” “strategy,” “target,” “anticipate,” “achieve,” “believe,” “contemplate,” “continue,” “could,” “estimate,” “expect,” “intends,” “may,” “plan,” “possible,” “project,” “should,” “will,” “would” and similar expressions (including the negatives of these terms or variations of them) may identify forward-looking statements, but the absence of these words does not mean that a statement is not forward-looking. These forward-looking statements are based on current expectations and beliefs concerning future developments and their potential effects. There can be no assurance that future developments affecting Jade will be those that have been anticipated. These forward-looking statements involve a number of risks, uncertainties (some of which are beyond Jade’s control) or other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements. These risks and uncertainties include, but are not limited to, the risks that the Phase 1 clinical trial of JADE101, the planned trial of JADE201 and any future clinical trials may be delayed or may not demonstrate desirable efficacy; adverse events and safety signals may occur; Jade may experience unanticipated costs, difficulties or delays in the product development process; Jade’s product candidates may fail in development, may not receive required regulatory approvals, or may be delayed to a point where they are not commercially viable; enrollment or regulatory challenges; risks associated with Jade’s dependence on third-party vendors for the development, manufacture and supply of its product candidates; and the other risks, uncertainties and factors more fully described in Jade’s most recent filings with the Securities and Exchange Commission (including the Quarterly Report on Form 10-Q for the quarter ended June 30, 2025). Should one or more of these risks or uncertainties materialize, or should any of Jade’s assumptions prove incorrect, actual results may vary in material respects from those projected in these forward-looking statements. You should not place undue reliance on forward-looking statements in this communication, which speak only as of the date they are made and are qualified in their entirety by reference to the cautionary statements herein. Jade does not undertake or accept any duty to release publicly any updates or revisions to any forward-looking statements. This communication does not purport to summarize all of the conditions, risks and other attributes of an investment in Jade. Jade Biosciences Contact Priyanka Shah [email protected] [email protected] 908-447-6134

Presented preclinical data for JADE101 at the 62nd European Renal Association Congress, highlighting its potential as a best-in-class anti-APRIL monoclonal antibody for IgA nephropathy Phase 1 healthy-volunteer study of JADE101 expected to begin in the third quarter of 2025, with interim, biomarker-rich data anticipated in the first half of 2026 $220.9 million cash and cash equivalents as of June 30, 2025 supports cash runway through 2027, including multiple clinical inflection points SAN FRANCISCO and VANCOUVER, British Columbia, Aug. 13, 2025 (GLOBE NEWSWIRE) -- Jade Biosciences, Inc. (“Jade”) (Nasdaq: JBIO), a biotechnology company focused on developing best-in-class therapies for autoimmune diseases, today announced financial results for the quarter ending June 30, 2025, and provided a corporate update. “We’ve had a productive second quarter, in which we closed our reverse merger and significant financing, and continued to advance a pipeline aimed at delivering potentially best-in-class therapies that treat systemic and organ-specific autoimmune diseases,” said Tom Frohlich, Chief Executive Officer of Jade. “We recently presented compelling preclinical data on JADE101, which we believe support its potential to be a best-in-class disease-modifying therapy for IgA nephropathy. Additionally, recently announced clinical data from other programs further reinforce our belief that the anti-APRIL class will be the foundational therapy for this disease. We are excited to transition into a clinical-stage company in the coming months, and believe we are uniquely positioned to shape the treatment landscape for IgAN and other autoimmune diseases.” Pipeline and Corporate Updates JADE101: potentially best-in-class anti-APRIL monoclonal antibody for IgA nephropathy (IgAN) Presented preclinical data for JADE101 at the 62nd European Renal Association Congress. JADE101 is an ultra-high affinity, half-life-extended fully-human monoclonal antibody that has the potential for best-in-class activity with convenient patient dosing. Key findings reported included: JADE101 showed ultra-high APRIL binding affinity (~50 femtomolar KD, >750-fold higher than sibeprenlimab), potent and complete inhibition of APRIL signaling in vitro, and deep, sustained IgA suppression, with an extended half-life of approximately 27 days, after a single 30 mg/kg intravenous dose in non-human primates (NHPs). The pharmacokinetic (PK) profile in NHPs—characterized by slow linear clearance to low concentrations, successful mitigation of target-mediated drug disposition, and high bioavailability following subcutaneous dosing—supports the potential for convenient, infrequent subcutaneous dosing of no more than every eight weeks in clinical settings. JADE101 binds a unique epitope on trimeric APRIL protein, which was selected to avoid the formation of high molecular weight immune complexes, with the goal of supporting more predictable PK and reduced immunogenicity risk. A Phase 1 clinical trial evaluating JADE101 administered as a subcutaneous injection in healthy volunteers is expected to begin in the third quarter of 2025. Interim, biomarker-rich data are expected in the first half of 2026 and are anticipated to guide dose and dose interval selection for later-stage JADE101 studies in patients with IgAN. JADE201: development candidate from the JADE-002 antibody discovery program JADE201, the Company’s development candidate from the JADE-002 antibody discovery program, remains on track to enter the clinic in the first half of 2026. JADE201 has the potential to be evaluated in multiple systemic autoimmune diseases. Further details on JADE201 are expected to be disclosed in the second half of 2025. Corporate Appointed Brad Dahms as Chief Financial Officer (CFO). Mr. Dahms is an accomplished biopharmaceutical executive who has held CFO and senior leadership roles at IDRx, Theseus Pharmaceuticals, and Selecta Biosciences following a career in investment banking at J.P. Morgan, RBC Capital Markets, and Cantor Fitzgerald. Second Quarter 2025 Financial Results Cash Position: As of June 30, 2025, Jade had cash and cash equivalents of $220.9 million. Based on the Company’s current operating plan, Jade believes that its cash and cash equivalents as of June 30, 2025 will enable it to fund its operating expenses and capital expenditure requirements through the end of 2027. Research and Development (R&D) expenses: R&D expenses totaled $22.5 million for the second quarter of 2025. Personnel related charges were $5.7 million, including $2.6 million of non-cash stock-based compensation expense. General and Administrative (G&A) expenses: G&A expenses totaled $5.2 million for the second quarter of 2025. These expenses include $3.1 million of personnel-related costs, including $1.4 million of non-cash stock-based compensation expense. Other expenses: Other expenses, net for the second quarter of 2025 were $4.4 million. This reflects $6.2 million of expense on the change in fair value of convertible notes before their conversion to common stock, partially offset by interest earned on Jade’s investment in money market funds of $1.8 million for the second quarter of 2025. Net loss: Net loss totaled $32.1 million for the second quarter of 2025, which includes non-cash stock-based compensation of $4.0 million. Shares Outstanding: As of June 30, 2025, Jade had 52.6 million shares of the Company’s common stock and common stock equivalents issued and outstanding, including shares of common stock underlying pre-funded warrants and non-voting convertible preferred. About Jade Biosciences, Inc. Jade Biosciences is focused on developing best-in-class therapies to address critical unmet needs in autoimmune diseases. Its lead candidate, JADE101, targets the cytokine APRIL for the treatment of immunoglobulin A nephropathy. Jade’s pipeline also includes a second development candidate, JADE201, and an undisclosed antibody discovery program, JADE-003, both currently in preclinical development. Jade was launched based on assets licensed from Paragon Therapeutics, an antibody discovery engine founded by Fairmount. For more information, visit JadeBiosciences.com and follow the Company on LinkedIn. Forward-Looking Statements Certain statements in this communication, other than purely historical information, may constitute “forward-looking statements” within the meaning of the federal securities laws, including for purposes of the “safe harbor” provisions under the Private Securities Litigation Reform Act of 1995. These forward-looking statements include, but are not limited to, express or implied statements relating to Jade’s expectations, hopes, beliefs, intentions or strategies regarding the future of its pipeline and business including, without limitation, Jade’s ability to achieve the expected benefits or opportunities with respect to JADE101, JADE201 and the JADE-003 program, the expected timelines for JADE101 and JADE201 entering the clinic and for interim data from the Phase 1 clinical trial of JADE101, the potential for the anti-APRIL class to be the foundational therapy for IgAN, the potential of Jade’s product candidates to become best-in-class therapies, their potential therapeutic uses and the potential for Jade’s cash to provide runway through 2027. The words “opportunity,” “potential,” “milestones,” “pipeline,” “can,” “goal,” “strategy,” “target,” “anticipate,” “achieve,” “believe,” “contemplate,” “continue,” “could,” “estimate,” “expect,” “intends,” “may,” “plan,” “possible,” “project,” “should,” “will,” “would” and similar expressions (including the negatives of these terms or variations of them) may identify forward-looking statements, but the absence of these words does not mean that a statement is not forward-looking. These forward-looking statements are based on current expectations and beliefs concerning future developments and their potential effects. There can be no assurance that future developments affecting Jade will be those that have been anticipated. These forward-looking statements involve a number of risks, uncertainties (some of which are beyond Jade’s control) or other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements. These risks and uncertainties include, but are not limited to, the risks that the planned trials of JADE101 and JADE201 and any future clinical trials may be delayed or may not demonstrate safety and/or efficacy; Jade may experience unanticipated costs, difficulties or delays in the product development process; Jade’s product candidates may fail in development, may not receive required regulatory approvals, or may be delayed to a point where they are not commercially viable; regulatory agencies may impose additional requirements or delay the initiation of clinical trials; risks associated with Jade’s dependence on third-party vendors for the development, manufacture and supply of JADE101; and the other risks, uncertainties and factors more fully described in Jade’s most recent filings with the Securities and Exchange Commission (including the definitive proxy statement/prospectus filed on Form S-4, most recently amended on March 24, 2025 and declared effective on March 25, 2025). Should one or more of these risks or uncertainties materialize, or should any of Jade’s assumptions prove incorrect, actual results may vary in material respects from those projected in these forward-looking statements. You should not place undue reliance on forward-looking statements in this communication, which speak only as of the date they are made and are qualified in their entirety by reference to the cautionary statements herein. Jade does not undertake or accept any duty to release publicly any updates or revisions to any forward-looking statements. This communication does not purport to summarize all of the conditions, risks and other attributes of an investment in Jade. Jade Biosciences Contact Priyanka Shah [email protected] [email protected] 908-447-6134

Completed reverse merger and commenced trading on Nasdaq as JBIO Closed financing, raising approximately $300 million to date, providing cash runway through 2027 Lead candidate JADE101 expected to enter the clinic in second half of 2025, with interim biomarker-rich data expected in first half of 2026 SAN FRANCISCO and VANCOUVER, British Columbia, May 14, 2025 (GLOBE NEWSWIRE) -- Jade Biosciences, Inc. (“Jade”) (Nasdaq: JBIO), a biotechnology company focused on developing best-in-class therapies for autoimmune diseases, today announced financial results for the quarter ending March 31, 2025, and provided a corporate update. “The start to 2025 marked a defining period for Jade Biosciences as we successfully completed our reverse merger, commenced trading as JBIO on Nasdaq, and closed a significant private financing led by a premier syndicate of healthcare investors,” said Tom Frohlich, Chief Executive Officer of Jade. “With a strong balance sheet, we are well-positioned to advance our pipeline of potentially best-in-class therapies for autoimmune diseases. We’re especially excited to become a clinical-stage company later this year, with JADE101 on track to begin first-in-human studies in the second half of 2025. This represents a meaningful step toward delivering differentiated treatment options for patients living with chronic and underserved autoimmune conditions.” Corporate and Pipeline Updates Corporate Completed the previously announced reverse merger with Aerovate Therapeutics, Inc., concurrently closed a private placement and began trading on Nasdaq under the ticker symbol JBIO. JADE101: potentially best-in-class anti-APRIL monoclonal antibody for IgAN First-in-human clinical trial anticipated to begin in the second half of 2025 with interim data expected in the first half of 2026. Anti-APRIL mechanism of action provides biomarker-rich data in healthy volunteers that is expected to be predictive of clinical efficacy and will define the dose and schedule designed to fully suppress APRIL throughout the dosing interval in IgAN patients. JADE201: a development candidate from the JADE-002 antibody discovery program Nominated a development candidate from the JADE-002 program, named JADE201. First Quarter 2025 Financial Results Cash Position: As of March 31, 2025, Jade had available cash and cash equivalents of $49.9 million. Net cash used in operating activities was $18.8 million for the first quarter of 2025. On April 28, 2025, the Company completed its reverse merger and closed on approximately $205 million of gross proceeds in conjunction with the transaction. The Company expects this cash to provide runway through 2027. Research and Development (R&D) expenses: R&D expenses totaled $20.0 million for the first quarter of 2025. These expenses include $1.7 million of non-cash stock-based compensation. During the first quarter of 2025, the Company incurred $10.0 million in development of JADE101 excluding personnel-related charges. General and Administrative (G&A) expenses: G&A expenses totaled $3.4 million for the first quarter of 2025. These expenses include $1.7 million of personnel-related costs, including $0.7 million of non-cash stock-based compensation related to equity awards to employees and service providers, and $1.5 million for professional, consulting, and other costs to operate a public company and support R&D activities. Other expense: Other expense, net for the first quarter of 2025 was $14.8 million. This reflects $15.4 million of expense on the change in fair value of convertible notes before their conversion to common stock, partially offset by interest earned on the Company’s investment in money market funds of $0.6 million for the first quarter of 2025. Net loss: Net loss totaled $38.2 million for the first quarter of 2025, which includes non-cash stock-based compensation of $2.4 million. Shares Outstanding: Subsequent to the merger, Jade has approximately 40,002,173 shares of common stock and common stock equivalents issued and outstanding, and 12,622,000 shares of common stock underlying Company Series A Preferred Stock issued and outstanding. About JADE101 JADE101 is an investigational anti-APRIL (A Proliferation-Inducing Ligand) monoclonal antibody being developed for the treatment of IgA nephropathy (IgAN), a chronic autoimmune kidney disease characterized by the deposition of pathogenic IgA-containing immune complexes in the kidneys. These deposits can lead to proteinuria, declining kidney function, and potentially end-stage kidney disease requiring dialysis or transplantation. By targeting APRIL, a protein involved in the overproduction of IgA, JADE101 aims to reduce the levels of disease-driving IgA, decrease proteinuria, and preserve kidney function. Engineered with half-life extension technology, JADE101 is designed for dosing at intervals of at least eight weeks, offering the potential for durable clinical activity and improved patient convenience, particularly important for a condition often diagnosed in young adulthood and potentially requiring life-long treatment. About Jade Biosciences, Inc. Jade Biosciences is focused on developing best-in-class therapies to address critical unmet needs in autoimmune diseases. Its lead candidate, JADE101, targets the cytokine APRIL for the treatment of immunoglobulin A nephropathy, with initiation of a first-in-human clinical trial expected in the second half of 2025. Jade’s pipeline also includes a second development candidate, JADE201, and an undisclosed antibody discovery program, JADE-003, both currently in preclinical development. Jade was launched based on assets licensed from Paragon Therapeutics, an antibody discovery engine founded by Fairmount. For more information, visit JadeBiosciences.com and follow the Company on LinkedIn. Forward-Looking Statements Certain statements in this communication, other than purely historical information, may constitute "forward-looking statements" within the meaning of the federal securities laws, including for purposes of the "safe harbor" provisions under the Private Securities Litigation Reform Act of 1995. These forward-looking statements include, but are not limited to, express or implied statements relating to Jade’s expectations, hopes, beliefs, intentions or strategies regarding the future of its pipeline and business including, without limitation, Jade’s ability to achieve the expected benefits or opportunities with respect to JADE101, JADE201 and the JADE-003 program, including the expected timelines for JADE101 entering the clinic and interim data from such trial, the potential for such data to be predictive of clinical efficacy and to define a dose and schedule to fully suppress APRIL throughout the dosing interval in IgAN patients, the potential of Jade’s product candidates to become best-in-class therapies and the potential for Jade’s cash to provide runway through 2027. The words "opportunity," "potential," "milestones," "pipeline," "can," "goal," "strategy," "target," "anticipate," "achieve," "believe," "contemplate," "continue," "could," "estimate," "expect," "intends," "may," "plan," "possible," "project," "should," "will," "would" and similar expressions (including the negatives of these terms or variations of them) may identify forward-looking statements, but the absence of these words does not mean that a statement is not forward-looking. These forward-looking statements are based on current expectations and beliefs concerning future developments and their potential effects. There can be no assurance that future developments affecting Jade will be those that have been anticipated. These forward-looking statements involve a number of risks, uncertainties (some of which are beyond Jade's control) or other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements. These risks and uncertainties include, but are not limited to, the risks that the planned trial of JADE101 and any future clinical trials may not demonstrate safety and/or efficacy; Jade may experience unanticipated costs, difficulties or delays in the product development process; Jade’s product candidates may fail in development, may not receive required regulatory approvals, or may be delayed to a point where they are not commercially viable; regulatory agencies may impose additional requirements or delay the initiation of clinical trials; risks associated with Jade’s dependence on third-party vendors for the development, manufacture and supply of JADE101; and the other risks, uncertainties and factors more fully described in Jade’s most recent filings with the Securities and Exchange Commission (including its definitive proxy statement/prospectus filed on Form S-4, most recently amended on March 24, 2025 and declared effective on March 25, 2025), as well as risk factors associated with companies, such as Jade, that operate in the biopharma industry. Should one or more of these risks or uncertainties materialize, or should any of Jade's assumptions prove incorrect, actual results may vary in material respects from those projected in these forward-looking statements. Nothing in this communication should be regarded as a representation by any person that the forward-looking statements set forth herein will be achieved or that any of the contemplated results of such forward-looking statements will be achieved. You should not place undue reliance on forward-looking statements in this communication, which speak only as of the date they are made and are qualified in their entirety by reference to the cautionary statements herein. Jade does not undertake or accept any duty to release publicly any updates or revisions to any forward-looking statements. This communication does not purport to summarize all of the conditions, risks and other attributes of an investment in Jade. Jade Biosciences Contacts Media Priyanka Shah Email: [email protected] Phone: 908-447-6134 Investors Email: [email protected]