CABA

Registrational RESET-Myositis® clinical data on track to be reported in mid-2027 to support 2H27 BLA submission for rese-cel Juvenile myositis Phase 1/2 data expected to be submitted with BLA to support potential FDA Priority Review Voucher Registrational RESET-SSc® enrollment in approximately 25 patients with SSc-associated interstitial lung disease anticipated to initiate in 4Q26 PC-free approach being incorporated in RESET-MG® based on emerging insights from PC-free RESET-SLE® and RESET-PV® cohorts and previously reported Phase 1/2 clinical data Pursuing expansion of outpatient dosing option for rese-cel within the RESET™ clinical development program based in part on favorable safety data reported at EULAR 2026 ElevateBio selected as second CDMO for clinical and commercial manufacturing of rese-cel PHILADELPHIA, Aug. 13, 2026 (GLOBE NEWSWIRE) -- Cabaletta Bio, Inc. (Nasdaq: CABA), a late-stage clinical biotechnology company focused on developing and launching curative targeted cell therapies designed specifically for patients with autoimmune diseases, today reported financial results for the second quarter ended June 30, 2026, and provided a business update. “A single infusion of rese-cel has demonstrated the potential to deliver deep, clinical responses after discontinuation of all immunomodulators with up to 1.5 years of follow-up as reported in the most recent Phase 1/2 clinical experience. Continued expansion of the outpatient dosing option with rese-cel remains a top priority, and we believe the reported safety profile supports its incorporation across the RESET clinical development program,” said Steven Nichtberger, M.D., Chief Executive Officer of Cabaletta. “Additionally, we view the product design and development characteristics of rese-cel, including the use of a fully-human CAR construct, weight-based dosing, and a well-characterized manufacturing process, to have contributed to the compelling clinical outcomes reported in adult and juvenile patients across multiple autoimmune diseases. As we progress rese-cel through and into registrational trials for myositis and systemic sclerosis, respectively, we are also particularly encouraged by the reported PC-free data in lupus and PV patients which have prompted us to incorporate the PC-free approach in RESET-MG.” Recent Operational Highlights and Anticipated Upcoming Milestones Resecabtagene autoleucel (rese-cel) for autoimmune diseasesCabaletta is advancing rese-cel as an investigational CAR T cell therapy designed to reset the immune system in patients living with autoimmune diseases. Following a single, weight-based intravenous infusion after discontinuation of immunomodulators, rese-cel has shown the ability to deliver an immune system reset in treated patients across multiple autoimmune diseases, leading to compelling clinical outcomes that have persisted over time. Cabaletta is evaluating rese-cel across the RESET (REstoring SElf-Tolerance) clinical development program, which includes multiple ongoing company-sponsored trials in rheumatology, neurology, and dermatology with disease-specific cohorts designed to evolve directly into registrational studies. Cabaletta is also advancing a program of innovations to broaden and deepen the treatment potential of rese-cel across autoimmune diseases. Registrational RESET-Myositis data on track for mid-2027 to support first potential BLA submission for rese-cel in 2H27 Cabaletta continues to anticipate reporting data from the registrational, 17-patient dermatomyositis (DM) and antisynthetase syndrome (ASyS) cohort in mid-2027, including 14 adult DM patients and 3 adult ASyS patients. If successful, Cabaletta plans to submit its first Biologics License Application (BLA) to the U.S. Food and Drug Administration (FDA) in 2H27, inclusive of data from the registrational cohort and the juvenile cohort which may facilitate the potential to be granted a Priority Review Voucher. At the European Alliance of Associations for Rheumatology (EULAR) 2026 Congress, Cabaletta presented Phase 1/2 data demonstrating that 80% (8/10) of evaluable adult DM and ASyS patients would have met the primary endpoint of the registrational cohort, with all DM responders maintaining their responses through up to 1.5 years of follow-up. Cabaletta also reported that the first juvenile DM patient achieved an immunomodulator-free moderate Total Improvement Score response at 16 weeks, which was maintained through latest follow-up at 32 weeks. Across all 17 RESET-Myositis Phase 1/2 patients reported at EULAR 2026, 100% experienced no or Grade 1 (fever) cytokine release syndrome (CRS) and none experienced immune effector cell-associated neurotoxicity syndrome (ICANS), reinforcing a safety profile supportive of the outpatient dosing option already incorporated in the trial. SSc-associated ILD selected as second registrational cohort to initiate in 4Q26 Based on complete RESET-SSc Phase 1/2 cohort data and FDA feedback, Cabaletta is preparing to conduct a single-arm registrational study in a new cohort of approximately 25 patients with systemic sclerosis (SSc)-associated interstitial lung disease (ILD) using a forced vital capacity-based primary endpoint at 52 weeks. Cabaletta anticipates initiating this study in 4Q26. Updated data from RESET-SSc presented at the EULAR 2026 Congress demonstrated that patients showed overall improvement in skin and improvement in lung disease activity, achieving clinical responses while off immunomodulators and off or tapering steroids that appeared to increase in magnitude with longer follow-up. PC-free approach being incorporated in RESET-MG and enrolling in higher-dose cohorts in RESET-PV and RESET-SLE Based on complete RESET-MG Phase 1/2 cohort data shared at the American Academy of Neurology Annual Meeting in April 2026 and emerging insights from the broader preconditioning (PC)-free program for rese-cel, Cabaletta is incorporating dose exploration with PC-free rese-cel in RESET-MG. In addition, rese-cel was granted Regenerative Medicine Advanced Therapy designation by the FDA for the treatment of generalized myasthenia gravis, building on this designation already granted to rese-cel as a potential treatment for myositis, systemic sclerosis, and lupus. Cabaletta presented PC-free data from RESET-PV at the American Society of Gene & Cell Therapy (ASGCT) 2026 Annual Meeting, with findings published in Blood, and from RESET-SLE at the EULAR 2026 Congress. Across both trials, rese-cel exhibited a predictable translational profile consistent with observations in patients treated with rese-cel and preconditioning. Based on the reported clinical findings, Cabaletta believes the lowest dose of rese-cel may represent a threshold dose in both trials and is advancing higher-dose cohorts in each trial. Manufacturing partnerships expanded for long-term supply chain resiliency at scale Cabaletta has partnered with ElevateBio as an additional contract development and manufacturing organization (CDMO) partner alongside Lonza, adding capacity and supply chain security to support the anticipated scale of demand for rese-cel across autoimmune indications. Cabaletta expects ElevateBio and Lonza to support the transition from clinical to commercial supply using our substantially closed and partially automated process with increased capacity that was implemented prior to registrational evaluation of rese-cel. As part of its automated manufacturing strategy, Cabaletta announced a 10-year commercial supply agreement with Cellares in April 2026. The agreement enables Cabaletta to leverage Cellares’ automated manufacturing capabilities to supply thousands of rese-cel batches per year with minimal capital investment and at a per batch cost anticipated to be among the lowest in the industry for autologous cell therapy production. At ASGCT 2026, translational data were presented demonstrating that rese-cel manufactured using the Cellares Cell Shuttle™ platform produces comparable CAR T cell expansion and B cell depletion kinetics relative to current clinical manufacturing processes, providing further proof of concept in addition to product comparability data for the Cellares automated manufacturing approach. Second Quarter 2026 Financial Results Research and development expenses were $44.4 million for the three months ended June 30, 2026, compared to $37.6 million for the same period in 2025. General and administrative expenses were $7.6 million for the three months ended June 30, 2026, compared to $8.3 million for the same period in 2025. As of June 30, 2026, Cabaletta had cash, cash equivalents, and short-term investments of approximately $225.1 million, inclusive of net proceeds from the May 2026 registered direct offering, compared to $133.6 million as of December 31, 2025. The Company expects that its cash position as of June 30, 2026, will enable it to fund its operating plan into mid-2027. About Cabaletta BioCabaletta Bio (Nasdaq: CABA) is a late-stage clinical biotechnology company focused on developing and launching curative targeted cell therapies designed specifically for patients with autoimmune diseases. Cabaletta’s lead product candidate, rese-cel, is an investigational 4-1BB-containing fully human CD19-CAR T cell therapy being advanced across the RESET™ (REstoring SElf-Tolerance) clinical development program spanning multiple therapeutic areas, including rheumatology, neurology and dermatology. Cabaletta Bio’s headquarters and labs are located in Philadelphia, PA. For more information, visit www.cabalettabio.com and connect with us on LinkedIn. Forward-Looking StatementsThis press release contains “forward-looking statements” of Cabaletta Bio within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including without limitation, express or implied statements regarding: Cabaletta’s business plans and objectives as a whole; Cabaletta’s ability to realize its vision of launching curative targeted cell therapies designed specifically for patients with autoimmune diseases; Cabaletta’s ability to successfully complete research and further development and commercialization of its drug candidates in current or future indications, including the timing and results of Cabaletta’s clinical trials and its ability to conduct and complete clinical trials; expectation that clinical results will support rese-cel’s safety and activity profile; statements regarding the timing of interactions with the FDA, including review of safety information from Cabaletta’s ongoing clinical trials and discussions with the FDA on potential registrational pathways for rese-cel, including the timing and acceptance of registrational designs related thereto; Cabaletta's expectations regarding the timing of topline data from the registrational DM/ASyS cohort in mid-2027 and its plans to submit a BLA for rese-cel in myositis, inclusive of adult and juvenile DM data, in 2H27; Cabaletta's expectations regarding the potential eligibility for a Priority Review Voucher based on Rare Pediatric Disease Designation for juvenile DM; Cabaletta's plans regarding the initiation of a SSc-associated ILD registrational program in 4Q26; significance of the clinical data read-out at upcoming scientific meetings and timing thereof; Cabaletta’s expectations around the potential success and therapeutic benefits of rese-cel; the advancement of clinical trials of rese-cel in patients with SLE, myositis, SSc, gMG and PV and advancement of the RESET-MS trial, including updates related to status, enrollment, safety data, trial design and timing of data read-outs or otherwise; Cabaletta’s plans and expectations regarding the timing and results of clinical data from patients treated with rese-cel without preconditioning; Cabaletta’s plans to generate and report PC-free dose-ranging data across multiple autoimmune indications; Cabaletta's expectations regarding the safety profile of rese-cel and its belief that such profile supports outpatient administration; Cabaletta's plans to expand the outpatient dosing option across the RESET clinical development program; Cabaletta's plans to advance rese-cel to potential commercial launch; Cabaletta's expectations regarding its manufacturing strategies, including the anticipated transition from clinical to commercial supply and plans to implement automated manufacturing of rese-cel with Cellares; the anticipated benefits of the 10-year commercial supply agreement with Cellares; and Cabaletta’s use of capital, expense and other financial results in the future and its ability to fund operations into mid-2027. Any forward-looking statements in this press release are based on management’s current expectations and beliefs of future events and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. These risks and uncertainties include, but are not limited to: risks related to regulatory filings and potential clearance; the risk that preclinical or clinical data, including signs of biologic activity or clinical response, may not be predictive of long-term results or translate across programs; Cabaletta’s ability to demonstrate sufficient evidence of safety, efficacy and tolerability in its preclinical studies and clinical trials of rese-cel; the risk that the results observed with the similarly-designed construct employed in academic publications, including due to the dosing regimen, are not indicative of the results Cabaletta seeks to achieve with rese-cel; risks that modifications to trial design or approach may not have the intended benefits and that the trial design may need to be further modified; risks related to clinical trial site activation, delays in enrollment generally or enrollment rates that are lower than expected; delays related to assessment of clinical trial results; risks related to unexpected safety or efficacy data observed during clinical studies; risks related to volatile market and economic conditions and public health crises; Cabaletta’s ability to retain and recognize the intended incentives conferred by Orphan Drug Designation, Fast Track Designation, Regenerative Medicine Advanced Therapy Designation or other designations for its product candidates, as applicable; risks related to Cabaletta’s ability to protect and maintain its intellectual property position; risks related to fostering and maintaining successful relationships with Cabaletta’s collaboration and manufacturing partners; uncertainties related to the initiation and conduct of studies and other development requirements for its product candidates; the risk that any one or more of Cabaletta’s product candidates will not be successfully developed and/or commercialized; and the risk that the initial or interim results of preclinical studies or clinical studies will not be predictive of future results in connection with future studies. For a discussion of these and other risks and uncertainties, and other important factors, any of which could cause Cabaletta’s actual results to differ from those contained in the forward-looking statements, see the section entitled “Risk Factors” in Cabaletta’s most recent annual report on Form 10-K as well as discussions of potential risks, uncertainties, and other important factors in Cabaletta’s other subsequent filings with the Securities and Exchange Commission. All information in this press release is as of the date of the release, and Cabaletta undertakes no duty to update this information unless required by law. ContactsInvestors: [email protected]: [email protected]

Preconditioning-free (PC-free) 6-to-9-month clinical data with a single infusion of the lowest dose of rese-cel in the RESET-PV® study presented today at ASGCT 2026 Annual Meeting along with initial rese-cel translational data using Cellares’ industrialized, automated manufacturing PC-free rese-cel initial data from the lowest dose RESET-SLE™ cohort expected in 1H26 Pivotal RESET-Myositis® cohort with outpatient dosing option progressing to support first planned BLA submission for rese-cel next year Second pivotal indication for advancement to be announced after presentation of complete Phase 1/2 lupus and scleroderma data during June 2026 EULAR Congress PHILADELPHIA, May 14, 2026 (GLOBE NEWSWIRE) -- Cabaletta Bio, Inc. (Nasdaq: CABA), a late-stage clinical biotechnology company focused on developing and launching curative targeted cell therapies designed specifically for patients with autoimmune diseases, today reported financial results for the first quarter ended March 31, 2026, and provided a business update. “Since January, while advancing our myositis pivotal trial and planning to initiate a second pivotal indication, we announced that we have signed a long-term commercial supply agreement with Cellares which provides the potential to produce rese-cel for thousands of patients per year at among the lowest cost of goods in the industry with minimal capital investment. In addition, today we are presenting data at ASGCT demonstrating that without preconditioning, even the lowest dose of rese-cel demonstrated compelling drug-free clinical responses in half of the pemphigus vulgaris patients through 6-months of follow-up,” said Steven Nichtberger, M.D., Chief Executive Officer of Cabaletta. “Later this quarter, we expect to announce initial data from the lowest dose cohort of lupus patients dosed without preconditioning. In the second half of 2026, we expect to report longer-term, PC-free rese-cel data from the lowest dose RESET-PV and RESET-SLE cohorts as well as data from patients treated with a higher PC-free dose of rese-cel. Bolstered by our recent oversubscribed financing, we believe we are well-positioned to advance rese-cel to BLA submission and potential commercial launch while continuing to differentiate and deliver rese-cel to autoimmune disease patients at scale.” Recent Operational Highlights and Upcoming Anticipated Milestones Rese-cel: Rese-cel (resecabtagene autoleucel) is an investigational, autologous CAR T cell therapy engineered with a fully human CD19 binder and a 4-1BB co-stimulatory domain, designed specifically for the treatment of autoimmune diseases. Administered as a single, weight-based infusion after discontinuation of all immunomodulators, rese-cel has demonstrated the ability to transiently, reliably and deeply deplete CD19-positive cells, with the goal of resetting the immune system and achieving durable clinical responses without the need for chronic therapy. Cabaletta is evaluating rese-cel in the RESET™ (REstoring SElf-Tolerance) clinical development program, which includes multiple ongoing company-sponsored trials across a broad range of autoimmune diseases in rheumatology, neurology and dermatology. 6-to-9-month rese-cel data in the lowest dose cohort without preconditioning from RESET-PV and initial clinical experience with Cellares-manufactured rese-cel being presented at the ASGCT 2026 Annual Meeting: Today, at the American Society of Gene & Cell Therapy (ASGCT) 2026 Annual Meeting, and further detailed in a separate press release issued today, Cabaletta is presenting clinical and translational data from four patients in the lowest PC-free dose cohort in RESET-PV. In addition, the initial clinical experience with Cellares-manufactured rese-cel, based on two evaluable patients, demonstrated CAR T cell expansion and B cell depletion at similar magnitudes and on similar timeframes relative to rese-cel manufactured by current clinical supply partners. Commercial supply capabilities expanded to build toward long-term, industrialized manufacturing using Cellares’ automated platforms: In April 2026, Cabaletta and Cellares announced a 10-year commercial supply agreement for rese-cel using Cellares’ automated Cell Shuttle™ in addition to future planned implementation of Cellares’ Cell Q™ platform. The Companies believe Cellares’ automated platforms for manufacturing and quality control release can enable flexible, low-cost scaling of commercial production of rese-cel to thousands of batches per year at a per batch cost believed to be among the lowest in the industry for autologous cell therapy production. The agreement builds on the Companies’ ongoing collaboration since 2023 to automate and industrialize the manufacturing of rese-cel. Registrational RESET-Myositis trial advancing and updates on registrational trial designs anticipated in 2026: Patient enrollment is progressing well in the registrational, 17-patient, single-arm dermatomyositis (DM) and antisynthetase syndrome (ASyS) cohort in RESET-Myositis. The cohort features a 16-week primary endpoint of moderate or major Total Improvement Score response while off immunomodulators and on no or low-dose steroids. If successful, data from this cohort will support Cabaletta’s first projected Biologics License Application (BLA) submission for rese-cel in myositis in 2027. In addition, Cabaletta anticipates providing an update regarding registrational trial designs for RESET-SSc™ in 1H26 and potentially for RESET-MG™ in mid-2026. Longer-term PC-free data at lowest dose and data at higher PC-free doses expected in 2H26: Cabaletta plans to share longer-term rese-cel data from the PC-free cohorts in RESET-PV and RESET-SLE at the lowest dose in 2H26. In addition, the Company expects to present data from higher dose patients throughout 2026. Complete Phase 1/2 cohort data from RESET-MG shared at AAN Annual Meeting: In April 2026, Cabaletta presented complete Phase 1/2 cohort data from RESET-MG at the American Academy of Neurology (AAN) Annual Meeting. Across 7 acetylcholine receptor (AChR)-positive and 6 AChR-negative patients who were evaluable, rese-cel exhibited a generally favorable risk-benefit profile with predictable peak expansion and associated B cell depletion. After discontinuation of immunomodulators, 5 AChR-positive and 5 AChR-negative patients experienced clinically meaningful improvement on the Myasthenia Gravis Activities of Daily Living score. Upcoming Scientific Presentations & Symposia Cabaletta expects to present multiple oral and poster presentations and to feature an abstract publication on rese-cel at the European Alliance of Associations for Rheumatology (EULAR) 2026 Congress, being held from June 3-6, 2026, in London, UK. Details are as follows: RESET-SLE (POS0698): Complete Phase 1/2 cohort data with preconditioning. Poster view presentation starting at 9:30 a.m. BST on Thursday, June 4, 2026. RESET-Myositis (OPO170): Longer-term follow-up from Phase 1/2 patients in the DM and ASyS cohorts. Oral abstract presentation starting at 9:15 a.m. BST on Thursday, June 4, 2026. RESET-SSc: Complete Phase 1/2 cohort data will be presented at a company-sponsored satellite symposium starting at 5:30 p.m. BST on Thursday, June 4, 2026. RESET development program (POS0351): Translational data from across several Phase 1/2 cohorts. Poster tour presentation starting at 10:39 a.m. BST on Saturday, June 6, 2026. Additional information can be accessed on the website of the EULAR 2026 Congress. Presentation materials will be made available on the Posters & Publications section of the Company’s website following their presentation. Corporate Updates Appointment of Francisco Ramírez-Valle, M.D., Ph.D., to Scientific Advisory Board: In May 2026, Cabaletta announced the appointment of Dr. Ramírez-Valle to its Scientific Advisory Board. Dr. Ramírez-Valle currently serves as Senior Vice President, Immunology Research at Eli Lilly and Company where he leads the discovery and early development of its immunology portfolio. He has over two decades of experience as a physician-scientist driving medical research, translational development and clinical development across all stages of preclinical research, human clinical trials and biomarker development. Raised $150 million in gross proceeds from registered direct offering: In May 2026, Cabaletta closed an underwritten registered direct offering, which included participation from Bain Capital Life Sciences, Adage Capital Management, Cormorant Asset Management and other existing investors, multiple new mutual and sovereign wealth funds and Eli Lilly and Company. The gross proceeds from the offering were approximately $150 million. Upcoming Investor Events Cabaletta plans to participate in the following upcoming investor conferences: H.C. Wainwright 4th Annual BioConnect Investor Conference at NASDAQ: Fireside chat at 4:00 p.m. ET on Tuesday, May 19, 2026, in New York, NY. Jefferies Global Healthcare Conference in New York: Fireside chat at 7:35 a.m. ET on Wednesday, June 3, 2026, in New York, NY. Goldman Sachs 47th Annual Global Healthcare Conference: Fireside chat at 10:00 a.m. ET on Monday, June 8, 2026, in Miami, FL. The fireside chats will be available on the News and Events section of the Company’s website at www.cabalettabio.com. Replays will be available for at least 30 days. First Quarter 2026 Financial Results Research and development expenses were $37.4 million for the three months ended March 31, 2026, compared to $29.0 million for the same period in 2025. General and administrative expenses were $6.9 million for the three months ended March 31, 2026, compared to $8.1 million for the same period in 2025. As of March 31, 2026, Cabaletta had cash, cash equivalents and short-term investments of $116.6 million, compared to $133.6 million as of December 31, 2025. The Company expects that its cash position as of March 31, 2026, along with cash raised from the May 2026 registered direct offering, will enable it to fund its operating plan into mid-2027. About Cabaletta Bio Cabaletta Bio (Nasdaq: CABA) is a late-stage clinical biotechnology company focused on developing and launching curative targeted cell therapies designed specifically for patients with autoimmune diseases. The CABA™ platform encompasses two complementary strategies which aim to advance the discovery and development of engineered T cell therapies with the potential to become deep and durable, perhaps curative, treatments for a broad range of autoimmune diseases. The lead CARTA (Chimeric Antigen Receptor T cells for Autoimmunity) strategy is prioritizing the development of rese-cel, a 4-1BB-containing fully human CD19-CAR T cell investigational therapy. Rese-cel is currently being evaluated in the RESET™ (REstoring SElf-Tolerance) clinical development program spanning multiple therapeutic areas, including rheumatology, neurology and dermatology. Cabaletta Bio’s headquarters and labs are located in Philadelphia, PA. For more information, please visit www.cabalettabio.com and connect with us on LinkedIn. Forward-Looking Statements This press release contains “forward-looking statements” of Cabaletta Bio within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including without limitation, express or implied statements regarding: Cabaletta’s business plans and objectives as a whole; Cabaletta’s ability to realize its vision of launching curative targeted cell therapies designed specifically for patients with autoimmune diseases; Cabaletta’s ability to successfully complete research and further development and commercialization of its drug candidates in current or future indications, including the timing and results of Cabaletta’s clinical trials and its ability to conduct and complete clinical trials; expectation that clinical results will support rese-cel’s safety and activity profile; statements regarding the timing of interactions with the FDA, including review of safety information from Cabaletta’s ongoing clinical trials and discussions with the FDA on potential registrational pathways for rese-cel, including the timing and acceptance of registrational designs related thereto and a BLA for rese-cel in myositis; the significance of the clinical data read-out at upcoming scientific meetings and timing thereof; Cabaletta’s expectations around the potential success and therapeutic benefits of rese-cel; the Company’s advancement of separate Phase 1/2 clinical trials of rese-cel in patients with SLE, myositis, SSc, gMG and PV and advancement of the RESET-MS trial, including updates related to status, enrollment, safety data, efficiency of clinical trial design and timing of initial data and durability data read-outs or otherwise; Cabaletta’s plans and expectations regarding the timing and results of clinical data from patients treated with rese-cel without preconditioning, including initial data from the lowest dose RESET-SLE cohort, longer-term data from the RESET-PV and RESET-SLE PC-free cohorts at the lowest dose and data from patients treated with a higher PC-free dose of rese-cel; Cabaletta's plans to announce additional clinical data from the RESET trials throughout 2026, including complete Phase 1/2 data to be presented from the RESET-SSc and RESET-SLE trials evaluating rese-cel with preconditioning; Cabaletta’s plans to advance rese-cel to potential commercial launch; Cabaletta’s plans to implement automated manufacturing of rese-cel with Cellares’ Cell Shuttle and future plans to implement Cellares' Cell Q platform, including the timing of initial translational data and longer-term clinical data from patients receiving Cellares-manufactured rese-cel and its expectation that such platforms can enable scalability to produce rese-cel for thousands of patients per year with minimal capital investment; the anticipated benefits of the 10-year commercial supply agreement with Cellares, including expectations regarding manufacturing cost efficiency, competitive per batch cost for autologous cell therapy production, and minimal capital investment; and Cabaletta’s use of capital, expense and other financial results in the future and its ability to fund operations into mid-2027. Any forward-looking statements in this press release are based on management’s current expectations and beliefs of future events and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. These risks and uncertainties include, but are not limited to: risks related to regulatory filings and potential clearance; the risk that signs of biologic activity or persistence may not inform long-term results; Cabaletta’s ability to demonstrate sufficient evidence of safety, efficacy and tolerability in its preclinical studies and clinical trials of rese-cel; the risk that the results observed with the similarly-designed construct employed in academic publications, including due to the dosing regimen, are not indicative of the results we seek to achieve with rese-cel; risks that results from one program may not translate to results for another program; risks that modifications to trial design or approach may not have the intended benefits and that the trial design may need to be further modified; risks related to clinical trial site activation, delays in enrollment generally or enrollment rates that are lower than expected; delays related to assessment of clinical trial results; risks related to unexpected safety or efficacy data observed during clinical studies; risks related to volatile market and economic conditions and public health crises; Cabaletta’s ability to retain and recognize the intended incentives conferred by Orphan Drug Designation, Fast Track Designation and Regenerative Medicine Advanced Therapy Designation or other designations for its product candidates, as applicable; risks related to Cabaletta’s ability to protect and maintain its intellectual property position; risks related to fostering and maintaining successful relationships with Cabaletta’s collaboration and manufacturing partners; uncertainties related to the initiation and conduct of studies and other development requirements for its product candidates; the risk that any one or more of Cabaletta’s product candidates will not be successfully developed and/or commercialized; and the risk that the initial or interim results of preclinical studies or clinical studies will not be predictive of future results in connection with future studies. For a discussion of these and other risks and uncertainties, and other important factors, any of which could cause Cabaletta’s actual results to differ from those contained in the forward-looking statements, see the section entitled “Risk Factors” in Cabaletta’s most recent annual report on Form 10-K as well as discussions of potential risks, uncertainties, and other important factors in Cabaletta’s other subsequent filings with the Securities and Exchange Commission. All information in this press release is as of the date of the release, and Cabaletta undertakes no duty to update this information unless required by law. Contacts: Anup Marda Chief Financial Officer [email protected]

Rese-cel myositis BLA submission on track for 2027 based on a 17-patient, single arm registrational cohort design, including an outpatient dosing option No-preconditioning program enrolling in lupus and PV; anticipating initial RESET-SLE™ data in 1H26 and durability data from the RESET-SLE and RESET-PV® trials throughout 2026 Automated manufacturing of rese-cel with Cellares’ Cell Shuttle™ underway in the RESET™ clinical program, offering the potential to produce rese-cel for thousands of patients per year with minimal capital investment Pivotal trial designs announced for SLE and LN single arm cohorts, each with ~25 patients; on track to announce SSc design in 1H26; FDA registrational design discussions and no preconditioning data will inform pivotal plans across the rese-cel program Complete Phase 1/2 data to be presented in 1H26 from the RESET-SSc™, RESET-SLE and RESET-MG™ trials evaluating rese-cel with preconditioning PHILADELPHIA, March 23, 2026 (GLOBE NEWSWIRE) -- Cabaletta Bio, Inc. (Nasdaq: CABA), a late-stage clinical biotechnology company focused on developing and launching the first curative targeted cell therapies designed specifically for patients with autoimmune diseases, today reported financial results for the fourth quarter and full year ended December 31, 2025, and provided a business update. “As we advance our core clinical programs for rese-cel with preconditioning and standard manufacturing, we have meaningfully advanced two potentially transformative innovations: rese-cel with no preconditioning and automated manufacturing using the Cellares Cell Shuttle. Clinical data on both innovations are on track to be shared in the first half of this year with durability data to follow later this year. Clinical data currently suggest that rese-cel offers a competitive profile that may reliably deliver an immune reset following a single, weight-based infusion with a safety profile that facilitates outpatient delivery with – or potentially without – preconditioning,” said Steven Nichtberger, M.D., Chief Executive Officer of Cabaletta. Recent Operational Highlights and Upcoming Anticipated Milestones Rese-cel: Rese-cel (resecabtagene autoleucel) is an investigational, autologous CAR T cell therapy engineered with a fully human CD19 binder and a 4-1BB co-stimulatory domain, designed specifically for the treatment of autoimmune diseases. Administered as a single, weight-based infusion, rese-cel has demonstrated the ability to transiently, reliably and deeply deplete CD19-positive cells, with the goal of resetting the immune system and achieving durable clinical responses without the need for chronic therapy. Cabaletta is evaluating rese-cel in the RESET™ (REstoring SElf-Tolerance) clinical development program, which includes multiple ongoing company-sponsored trials across a broad range of autoimmune diseases in rheumatology, neurology and dermatology. Registrational DM/ASyS cohort in RESET-Myositis® enrolling with outpatient dosing option: The registrational dermatomyositis (DM) and antisynthetase syndrome (ASyS) cohort is enrolling and is expected to evaluate 17 patients with a 16-week primary endpoint of moderate or major total improvement score response while off immunomodulators and on no or low-dose steroids. If successful, data from this cohort will support Cabaletta’s first projected Biologics License Application (BLA) submission for rese-cel in myositis in 2027. First clinical experience using automated Cellares manufacturing platform expected in 1H26: Cabaletta anticipates reporting the initial clinical experience with rese-cel manufactured by Cellares in 1H26. The initial clinical experience is intended to confirm current Good Manufacturing Practice (GMP) readiness, including supply chain logistics, for Cellares-produced rese-cel implementation across the rese-cel portfolio. Longer-term clinical data from patients receiving rese-cel manufactured by Cellares are expected in 2H26. If successful, the Cellares Integrated Development and Manufacturing Organization (IDMO) Smart Factory has the potential to enable scalability to produce rese-cel for thousands of patients per year with minimal capital investment, lower manufacturing costs through decreased labor requirements with improved scheduling flexibility after commercialization and rapid expansion to global capacity. Cabaletta continues to work with its existing manufacturing partners to support the myositis registrational trial and launch-readiness efforts for rese-cel. No-preconditioning program advancing in RESET-SLE and RESET-PV: Clinical data from patients treated with a single weight-based dose of rese-cel with no preconditioning are expected from the RESET-SLE trial in 1H26 (initial data) and 2H26 (durability data). Additionally, dose-ranging durability data from the RESET-PV trial are anticipated throughout 2026, supplementing the initial low dose PV data without preconditioning that were previously presented. Recent Nature Biotechnology publication and company presentation at the 2025 ASH Annual Meeting highlight rese-cel safety data across autoimmune portfolio: A recent Nature Biotechnology review, which included rese-cel clinical data, highlighted that CAR T administration in autoimmune diseases has shown a more favorable safety profile when compared to its use in the oncology setting. In addition, Cabaletta’s presentation at the 2025 ASH Annual Meeting expanded on these data, showing that in the first 40 patients treated with rese-cel with preconditioning, 95% of patients had either no cytokine release syndrome (CRS) or Grade 1 CRS and 95% of patients experienced no immune effector cell-associated neurotoxicity syndrome. Complete Phase 1/2 data anticipated from three RESET trials to be presented in 1H26: Complete Phase 1/2 clinical data from cohorts in RESET-SLE, RESET-SSc and RESET-MG are expected to be presented in 1H26. In RESET-MG, data will be presented in an oral presentation at 1:24 p.m. CDT on Monday, April 20, 2026, at the American Academy of Neurology (AAN) Annual Meeting in Chicago, IL. Complete Phase 1/2 clinical data from cohorts in RESET-SLE and RESET-SSc are also expected in 1H26. These clinical data are expected to support Cabaletta’s discussions with the FDA on potential registrational pathways specifically in RESET-SSc and RESET-MG. Cabaletta anticipates providing an update regarding registrational designs for RESET-SSc in 1H26 and for RESET-MG in mid-2026. Fourth Quarter and Full Year 2025 Financial Results Research and development expenses were $36.2 million and $142.7 million for the three months and full year ended December 31, 2025, respectively, compared to $25.5 million and $97.2 million for the three months and full year ended December 31, 2024, respectively. General and administrative expenses were $6.4 million and $29.6 million for the three months and full year ended December 31, 2025, respectively, compared to $8.3 million and $27.9 million for the three months and full year ended December 31, 2024, respectively. As of December 31, 2025, Cabaletta had cash, cash equivalents and short-term investments of $133.6 million, compared to $164.0 million as of December 31, 2024. Since December 31, 2025, the Company has raised an additional $30.0 million from a combination of ATM sales and exercise of certain common stock warrants set to expire in September 2026. The Company expects that its cash position as of December 31, 2025, along with cash raised during the first quarter of 2026, will enable it to fund its operating plan into the fourth quarter of 2026. About Cabaletta Bio Cabaletta Bio (Nasdaq: CABA) is a late-stage clinical biotechnology company focused on developing and launching the first curative targeted cell therapies designed specifically for patients with autoimmune diseases. The CABA™ platform encompasses two complementary strategies which aim to advance the discovery and development of engineered T cell therapies with the potential to become deep and durable, perhaps curative, treatments for a broad range of autoimmune diseases. The lead CARTA (Chimeric Antigen Receptor T cells for Autoimmunity) strategy is prioritizing the development of rese-cel, a 4-1BB-containing fully human CD19-CAR T cell investigational therapy. Rese-cel is currently being evaluated in the RESET™ (REstoring SElf-Tolerance) clinical development program spanning multiple therapeutic areas, including rheumatology, neurology and dermatology. Cabaletta Bio’s headquarters and labs are located in Philadelphia, PA. For more information, please visit www.cabalettabio.com and connect with us on LinkedIn. Forward-Looking Statements This press release contains “forward-looking statements” of Cabaletta Bio within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including without limitation, express or implied statements regarding: Cabaletta’s business plans and objectives as a whole; Cabaletta’s ability to realize its vision of launching the first curative targeted cell therapy designed specifically for patients with autoimmune diseases; Cabaletta’s ability to successfully complete research and further development and commercialization of its drug candidates in current or future indications, including the timing and results of Cabaletta’s clinical trials and its ability to conduct and complete clinical trials; expectation that clinical results will support rese-cel’s safety and activity profile; statements regarding the timing of interactions with the FDA, including review of safety information from Cabaletta’s ongoing clinical trials and discussions with the FDA on potential registrational pathways for rese-cel, including the timing of registrational designs related thereto; Cabaletta’s ability to leverage its emerging clinical data and its efficient development strategy; Cabaletta’s belief that it has meaningfully advanced two potentially transformative innovations; Cabaletta’s expectation around its clinical data that suggests that rese-cel can reliably deliver an immune reset following a single weight-based infusion with a safety profile that facilitates outpatient delivery with or potentially without preconditioning; Cabaletta’s ability to capitalize on and potential benefits resulting from its research and translational insights; the clinical significance of the clinical data read-out at upcoming scientific meetings and timing thereof; Cabaletta’s expectations around the potential success and therapeutic benefits of rese-cel; the Company’s advancement of separate Phase 1/2 clinical trials of rese-cel in patients with SLE, myositis, SSc, gMG and PV and advancement RESET-MS trial, including updates related to status, enrollment, safety data, efficiency of clinical trial design and timing of initial data and durability data read-outs or otherwise; Cabaletta’s plans of discussions with the FDA on registrational cohort designs and timing thereof; Cabaletta’s plans to announce additional clinical data from the RESET trials throughout 2026, including complete Phase 1/2 data to be presented in 1H26 from the RESET-SSc, RESET-SLE and RESET-MG trials evaluating rese-cel with preconditioning; Cabaletta’s expectations that the additional clinical data from the RESET trials will inform discussions with the FDA regarding registrational cohort designs for rese-cel in various indications; Cabaletta’s plans to submit a BLA for rese-cel in myositis in 2027 and obtain regulatory approval from the FDA and other regulatory authorities; Cabaletta’s plans to implement automated manufacturing of rese-cel with Cellares’ Cell Shuttle, including timing of initial clinical experience and durability data and its expectation that it can enable scalability to treat thousands of patients per year with minimal capital investment; and Cabaletta’s use of capital, expense and other financial results in the future and its ability to fund operations into the fourth quarter of 2026. Any forward-looking statements in this press release are based on management’s current expectations and beliefs of future events and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. These risks and uncertainties include, but are not limited to: risks related to regulatory filings and potential clearance; the risk that signs of biologic activity or persistence may not inform long-term results; Cabaletta’s ability to demonstrate sufficient evidence of safety, efficacy and tolerability in its preclinical studies and clinical trials of rese-cel; the risk that the results observed with the similarly-designed construct employed in academic publications, including due to the dosing regimen, are not indicative of the results we seek to achieve with rese-cel; risks that results from one program may not translate to results for another program; risks that modifications to trial design or approach may not have the intended benefits and that the trial design may need to be further modified; risks related to clinical trial site activation, delays in enrollment generally or enrollment rates that are lower than expected; delays related to assessment of clinical trial results; risks related to unexpected safety or efficacy data observed during clinical studies; risks related to volatile market and economic conditions and public health crises; Cabaletta’s ability to retain and recognize the intended incentives conferred by Orphan Drug Designation and Fast Track Designation or other designations for its product candidates, as applicable; risks related to Cabaletta’s ability to protect and maintain its intellectual property position; risks related to fostering and maintaining successful relationships with Cabaletta’s collaboration and manufacturing partners; uncertainties related to the initiation and conduct of studies and other development requirements for its product candidates; the risk that any one or more of Cabaletta’s product candidates will not be successfully developed and/or commercialized; and the risk that the initial or interim results of preclinical studies or clinical studies will not be predictive of future results in connection with future studies. For a discussion of these and other risks and uncertainties, and other important factors, any of which could cause Cabaletta’s actual results to differ from those contained in the forward-looking statements, see the section entitled “Risk Factors” in Cabaletta’s most recent annual report on Form 10-K as well as discussions of potential risks, uncertainties, and other important factors in Cabaletta’s other subsequent filings with the Securities and Exchange Commission. All information in this press release is as of the date of the release, and Cabaletta undertakes no duty to update this information unless required by law. Contacts: Anup Marda Chief Financial Officer [email protected]

Rese-cel data presented at multiple medical meetings demonstrated potentially transformative, drug-free clinical responses with a favorable safety profile for autoimmune patients supporting outpatient use All myositis patients in the Phase 1/2 DM/ASyS cohort with sufficient follow-up who would have met key criteria for the registrational cohort met the registrational, 16-week primary endpoint Planned BLA submission for rese-cel in 2027 based on 14-patient, single-arm DM/ASyS registrational cohort initiating enrollment this quarter within the RESET-Myositis™ trial FDA alignment on additional registrational cohort designs for RESET-SSc™ and RESET-SLE™ anticipated by year-end 2025 PHILADELPHIA, Nov. 10, 2025 (GLOBE NEWSWIRE) -- Cabaletta Bio, Inc. (Nasdaq: CABA), a clinical-stage biotechnology company focused on developing and launching the first curative targeted cell therapies designed specifically for patients with autoimmune diseases, today reported financial results for the third quarter ended September 30, 2025, and provided a business update. “Our team continued to execute with discipline and precision to extend our leadership through the RESET™ clinical development program. Rapid enrollment has resulted in multiple clinical data presentations highlighting rese-cel’s ability to deliver drug-free, transformative clinical responses for patients across multiple autoimmune diseases,” said Steven Nichtberger, M.D., Chief Executive Officer of Cabaletta. “In addition, the early no preconditioning data from our initial dose cohort support our plan to evaluate the efficacy and durability of rese-cel in lupus and other autoimmune patients using a single, weight-based dose without preconditioning.” Recent Operational Highlights and Upcoming Anticipated Milestones Rese-cel: Rese-cel (resecabtagene autoleucel, formerly CABA-201) is an investigational, autologous CAR T cell therapy engineered with a fully human CD19 binder and a 4-1BB co-stimulatory domain, designed specifically for the treatment of autoimmune diseases. Administered as a single, weight-based infusion, rese-cel is intended to transiently and deeply deplete CD19-positive cells, with the goal of resetting the immune system and achieving durable clinical responses without the need for chronic therapy. Cabaletta is evaluating rese-cel in the RESET (REstoring SElf-Tolerance) clinical development program, which includes multiple ongoing company-sponsored trials across a diverse and growing range of autoimmune diseases in rheumatology, neurology and dermatology. Clinical Development Presented positive new and longer-term clinical data from 32 patients across four autoimmune trials: At multiple medical meetings in October 2025, Cabaletta shared encouraging results from patients treated with rese-cel in myositis, systemic sclerosis, lupus, and myasthenia gravis, including full Phase 1/2 data from RESET-Myositis and preliminary data from RESET-SSc, RESET-SLE, and RESET-MG™ trials. These findings highlight rese-cel’s potential to deliver transformative, drug-free responses for patients with a favorable safety profile that can support outpatient use. Initial, low-dose no preconditioning data presented and expansion of approach into lupus: At the 2025 European Society of Gene & Cell Therapy Annual Congress, Cabaletta presented initial data from the RESET-PV™ trial evaluating a low dose of rese-cel without preconditioning in patients with pemphigus vulgaris, demonstrating complete B cell depletion in 2 of 3 patients along with early clinical responses with a generally well-tolerated profile. Based on these data, Cabaletta is expanding patient enrollment in the RESET-PV trial at the current dose, with the potential to evaluate higher doses, as warranted. In addition, Cabaletta is incorporating a new dose-escalation cohort in the RESET-SLE trial to evaluate rese-cel without preconditioning given the clinical responses observed in lupus following complete B cell depletion after administration of rese-cel with preconditioning. Initiation of myositis registrational DM/ASyS cohort anticipated by year-end 2025: Consistent with the previously announced alignment with the U.S. Food and Drug Administration (FDA) on registrational cohort design, which is based on several interactions, including direct review and feedback on the registrational trial protocol in August 2025, we are aligned on the dermatomyositis (DM) and antisynthetase syndrome (ASyS) registrational cohort with a 16-week primary endpoint of moderate or major total improvement score response while off immunomodulators and on no or low-dose steroids. The planned size of 14 patients for the registrational cohort is based on the assumed treatment effect of rese-cel in DM/ASyS patients and an estimated background rate. The estimated background rate will be determined from an external myositis patient registry, as aligned with the FDA, and will include patients with similar inclusion criteria as those in the registrational DM/ASyS cohort. In the Phase 1/2 DM/ASyS cohort, all patients with sufficient follow-up who would have met key criteria for the registrational cohort met the registrational primary endpoint. If successful, data from the DM/ASyS cohort will be used in part to support the Company’s first projected Biologics License Application (BLA) submission for rese-cel in myositis in 2027. Additional clinical data from RESET trials expected throughout 2026: On December 6, 2025, Cabaletta will present a poster titled “Mechanistic basis of the acute safety profile of rese-cel, an autologous CD19-CAR T, in patients with autoimmune disease treated in four ongoing phase 1/2 clinical trials” at the 67th American Society of Hematology Annual Meeting and Exposition, taking place in Orlando, FL. In addition, Cabaletta plans to present complete Phase 1/2 data from the RESET-SSc and RESET-SLE trials in the first half of 2026 and from the RESET-MG trial in the second half of 2026. The Company also anticipates clinical data on rese-cel without preconditioning from the initial RESET-SLE dose-escalation cohort and additional dosing from the RESET-PV trial in 2026. Regulatory New PRIME, RMAT and Fast Track regulatory designations granted by EMA and FDA: The Committee for Medicinal Products for Human Use of the European Medicines Agency (EMA) granted PRIME scheme access for rese-cel for the treatment of myositis during its September 2025 meeting. Through PRIME, the EMA offers early and proactive support to medicine developers to optimize the generation of robust data on a medicine’s benefits and risks and enable accelerated assessment of medicines applications. In addition, the FDA has granted new regulatory designations to rese-cel, including Regenerative Medicine Advanced Therapy (RMAT) designation for the treatment of systemic lupus erythematosus and lupus nephritis and Fast Track Designation for generalized myasthenia gravis. FDA alignment on additional registrational cohort designs expected through 2026: Cabaletta expects to align with the FDA on key registrational design elements for the RESET-SSc and RESET-SLE trials by year-end 2025 and for the RESET-MG trial in the first half of 2026. Subject to clinical data and regulatory alignment on registrational cohort design elements for these trials, the Company expects to initiate enrollment in registrational cohorts in 2026. Corporate Updates Appointment of Chief Commercial Officer: In October 2025, Steve Gavel was appointed Chief Commercial Officer. Mr. Gavel brings highly relevant CAR T experience from Legend Biotech where he led the launch and commercialization of CARVYKTI® from 2018 until 2025. In his role at Cabaletta, he will lead all aspects of global commercial strategy and execution for rese-cel as well as potential future pipeline opportunities. Third Quarter 2025 Financial Results Research and development expenses were $39.8 million for the three months ended September 30, 2025, compared to $26.3 million for the same period in 2024. General and administrative expenses were $6.8 million for the three months ended September 30, 2025, compared to $6.8 million for the same period in 2024. As of September 30, 2025, Cabaletta had cash, cash equivalents and short-term investments of $159.9 million, compared to $164.0 million as of December 31, 2024. The Company expects that its cash position as of September 30, 2025, will enable it to fund its operating plan into the second half of 2026. About Cabaletta Bio Cabaletta Bio (Nasdaq: CABA) is a clinical-stage biotechnology company focused on developing and launching the first curative targeted cell therapies designed specifically for patients with autoimmune diseases. The CABA™ platform encompasses two complementary strategies which aim to advance the discovery and development of engineered T cell therapies with the potential to become deep and durable, perhaps curative, treatments for a broad range of autoimmune diseases. The lead CARTA (Chimeric Antigen Receptor T cells for Autoimmunity) strategy is prioritizing the development of rese-cel, a 4-1BB-containing fully human CD19-CAR T cell investigational therapy. Rese-cel is currently being evaluated in the RESET™ (REstoring SElf-Tolerance) clinical development program spanning multiple therapeutic areas, including rheumatology, neurology and dermatology. Cabaletta Bio’s headquarters and labs are located in Philadelphia, PA. For more information, please visit www.cabalettabio.com and connect with us on LinkedIn. Forward-Looking Statements This press release contains “forward-looking statements” of Cabaletta Bio within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including without limitation, express or implied statements regarding: Cabaletta’s business plans and objectives as a whole; Cabaletta’s ability to realize its vision of launching the first curative targeted cell therapy designed specifically for patients with autoimmune diseases; Cabaletta’s ability to successfully complete research and further development and commercialization of its drug candidates in current or future indications, including the timing and results of Cabaletta’s clinical trials and its ability to conduct and complete clinical trials; expectation that clinical results will support rese-cel’s safety and activity profile; statements regarding the timing of interactions with regulatory authorities, including such authorities’ review of safety information from Cabaletta’s ongoing clinical trials and alignment with regulatory authorities on potential registrational pathway for rese-cel; Cabaletta’s ability to leverage its emerging clinical data and its efficient development strategy; Cabaletta’s belief that its new data demonstrates rese-cel’s ability to deliver drug-free, transformative clinical responses for patients across multiple autoimmune diseases and that the early no preconditioning data from its initial dose cohort has opened new opportunities to potentially treat autoimmune patients using a single weight-based dose of rese-cel without preconditioning; Cabaletta’s expectations that the milestones it has achieved underscores the potential of rese-cel to redefine treatment paradigms and bring drug-free remission to patients with high unmet need and also that its findings highlight rese-cel’s potential to deliver transformative, drug-free responses for patients with a favorable safety profile that can support outpatient use; Cabaletta’s ability to capitalize on and potential benefits resulting from its research and translational insights; the clinical significance of the clinical data read-out at upcoming scientific meetings and timing thereof; Cabaletta’s expectations around the potential success and therapeutic benefits of rese-cel, including its belief that rese-cel has the potential to reset the immune system and achieve durable clinical responses without the need for chronic therapy; the Company’s advancement of separate Phase 1/2 clinical trials of rese-cel in patients with SLE, myositis, SSc, gMG and PV and advancement RESET-MS trial, including updates related to status, enrollment, safety data, efficiency of clinical trial design and timing of data read-outs or otherwise; Cabaletta’s ability to initiate the myositis registrational trial and timing thereof; Cabaletta’s plans to expand patient enrollment in the RESET-PV trial at the current dose, with the potential to evaluate higher doses; Cabaletta’s expectations regarding the new dose-escalation cohort in the RESET-SLE trial to evaluate rese-cel without preconditioning based on the clinical responses observed in lupus; Cabaletta’s plans to initiate enrollment in the registrational DM/ASyS cohort in 2025; Cabaletta’s plans to announce additional clinical data from RESET trials throughout 2026; Cabaletta’s expectations around alignment with FDA on key registrational design elements for the RESET-SSc and RESET-SLE trials by year-end 2025 and for the RESET-MG trial in the first half of 2026; Cabaletta’s expectations to initiate enrollment in registrational cohorts in 2026; Cabaletta’s plans to submit a BLA for rese-cel in myositis in 2027 and obtain regulatory approval from the FDA and other regulatory authorities and Cabaletta’s use of capital, expense and other financial results in the future and its ability to fund operations into the second half of 2026. Any forward-looking statements in this press release are based on management’s current expectations and beliefs of future events and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. These risks and uncertainties include, but are not limited to: risks related to regulatory filings and potential clearance; the risk that signs of biologic activity or persistence may not inform long-term results; Cabaletta’s ability to demonstrate sufficient evidence of safety, efficacy and tolerability in its preclinical studies and clinical trials of rese-cel; the risk that the results observed with the similarly-designed construct employed in academic publications, including due to the dosing regimen, are not indicative of the results we seek to achieve with rese-cel; risks that results from one program may not translate to results for another program; risks that modifications to trial design or approach may not have the intended benefits and that the trial design may need to be further modified; risks related to clinical trial site activation, delays in enrollment generally or enrollment rates that are lower than expected; delays related to assessment of clinical trial results; risks related to unexpected safety or efficacy data observed during clinical studies; risks related to volatile market and economic conditions and public health crises; Cabaletta’s ability to retain and recognize the intended incentives conferred by Orphan Drug Designation and Fast Track Designation or other designations for its product candidates, as applicable; risks related to Cabaletta’s ability to protect and maintain its intellectual property position; risks related to fostering and maintaining successful relationships with Cabaletta’s collaboration and manufacturing partners; uncertainties related to the initiation and conduct of studies and other development requirements for its product candidates; the risk that any one or more of Cabaletta’s product candidates will not be successfully developed and/or commercialized; and the risk that the initial or interim results of preclinical studies or clinical studies will not be predictive of future results in connection with future studies. For a discussion of these and other risks and uncertainties, and other important factors, any of which could cause Cabaletta’s actual results to differ from those contained in the forward-looking statements, see the section entitled “Risk Factors” in Cabaletta’s most recent annual report on Form 10-K as well as discussions of potential risks, uncertainties, and other important factors in Cabaletta’s other subsequent filings with the Securities and Exchange Commission. All information in this press release is as of the date of the release, and Cabaletta undertakes no duty to update this information unless required by law. Contacts: Anup Marda Chief Financial Officer [email protected]

Cabaletta Bio (CABA) drew fresh attention from investors after announcing encouraging clinical trial results for rese-cel in several autoimmune diseases. Presentations at the American College of Rheumatology Convergence showcased their progress and prepared the company for key regulatory updates. See our latest analysis for Cabaletta Bio. All this news comes on the heels of a remarkable run for Cabaletta Bio’s share price, which climbed 86% over the last 90 days, clearly reflecting growing excitement as clinical and business milestones stack up. Even with a 36% decrease in total shareholder return over the past year, recent momentum hints at renewed optimism and shifting risk perceptions following the company’s strong data presentations and expansion of investor outreach. If Cabaletta’s recent surge caught your attention, now is a smart time to see what other healthcare innovators are making waves — See the full list for free. After such an impressive rally, investors are now left to wonder whether Cabaletta Bio’s current valuation still offers upside or if the market has already factored in all the company’s potential growth. Cabaletta Bio’s shares are trading at a price-to-book ratio of 1.4x, notably below the US Biotechs industry average of 2.5x. This suggests that investors are currently valuing the stock at a significant discount compared to its peers when measured by net asset value. The price-to-book ratio compares the market value of a company’s shares with its book value. For biotech firms like Cabaletta Bio, where traditional earnings measures may not be relevant due to a lack of profitability or revenue, price-to-book can highlight how the market views the company’s assets and future prospects relative to others in the space. This below-average price-to-book multiple could indicate market caution around Cabaletta’s profitability outlook, or possibly skepticism about the realization of asset value given clinical stage risks. Still, the disparity with industry and peer averages is stark. There could be a sizable gap for the market to close if sentiment improves for the company. See what the numbers say about this price — find out in our valuation breakdown. Result: Price-to-Book of 1.4x (UNDERVALUED) However, clinical-stage uncertainties and consistent net losses remain key risks. These factors could quickly shift sentiment and impact Cabaletta Bio’s valuation outlook. Find out about the key risks to this Cabaletta Bio narrative. Looking at Cabaletta Bio through the lens of our DCF model offers a strikingly different picture. The stock’s current price of $2.70 sits roughly 78% below our estimate of its fair value at $12.25. This suggests significantly more potential upside than the price-to-book ratio alone implies. Could the market be overlooking something key in its current assessment? Look into how the SWS DCF model arrives at its fair value. Simply Wall St performs a discounted cash flow (DCF) on every stock in the world every day (check out Cabaletta Bio for example). We show the entire calculation in full. You can track the result in your watchlist or portfolio and be alerted when this changes, or use our stock screener to discover 841 undervalued stocks based on their cash flows. If you save a screener we even alert you when new companies match - so you never miss a potential opportunity. If you see things differently or would rather draw your own conclusions, you can quickly build a personalized narrative to reflect your own analysis. Do it your way A great starting point for your Cabaletta Bio research is our analysis highlighting 1 key reward and 5 important warning signs that could impact your investment decision. Great investment opportunities rarely wait around. If you are serious about navigating today’s fast-moving markets, check out these opportunities that could reshape your portfolio. Capture early-stage growth by targeting these 3603 penny stocks with strong financials poised to potentially deliver outsized returns before Wall Street takes notice. Boost your passive income and strengthen your portfolio by tapping into these 18 dividend stocks with yields > 3% with attractive yields above 3%. Accelerate your exposure to the future of finance with these 82 cryptocurrency and blockchain stocks that harness the disruptive power of blockchain innovation and cryptocurrencies. 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 CABA. Have feedback on this article? Concerned about the content? Get in touch with us directly. Alternatively, email [email protected]

Cabaletta Bio (CABA) has attracted fresh attention after presenting early data from its RESET-PV clinical trial at the ESGCT Congress. The company reported that its CAR T cell therapy, rese-cel, achieved promising results in pemphigus vulgaris patients without preconditioning. See our latest analysis for Cabaletta Bio. Following the RESET-PV update, Cabaletta Bio’s share price has seen dramatic swings: a 42% surge in the past three months captures the excitement, while the 1-year total shareholder return remains deeply negative at -45%. This jump reflects renewed optimism around clinical progress, but the volatile track record highlights how investor sentiment often pivots quickly on biotech headlines. Long-term returns remain mixed. If breakthrough therapies are on your radar, it’s worth exploring other innovators in the space. See the full list of healthcare stocks at See the full list for free. With Cabaletta Bio’s bold data fueling debate and shares still well below analyst price targets, investors have to ask: Is the market overlooking the potential here, or is all the good news already built in? Based on its price-to-book ratio of 1.2x, Cabaletta Bio's stock appears notably cheap when compared to both its industry and its peer averages, especially given the last close at $2.32 per share. The price-to-book ratio compares a company’s market value to its book value, giving investors insight into how much they are paying for the assets net of liabilities. For biotechs, where profitability may be far off, this metric offers a baseline to gauge market expectations versus reality. Cabaletta Bio trades at less than half the US Biotechs industry average (2.5x) and at a fraction of the peer group average (30.9x). This deep discount suggests investors remain highly skeptical, despite the company’s bold clinical advancements. If market sentiment improves or the science delivers, there could be significant rerating potential to levels that better reflect industry standards. See what the numbers say about this price — find out in our valuation breakdown. Result: Price-to-Book Ratio of 1.2x (UNDERVALUED) However, persistent losses and a sharp one-year decline show that clinical setbacks or continued lack of profitability could quickly reverse investor optimism. Find out about the key risks to this Cabaletta Bio narrative. Switching gears, the Simply Wall St DCF model suggests a much bigger upside. According to this approach, Cabaletta Bio's fair value is $35.13 per share. This means the stock is trading at more than 90% below this estimate. Does this substantial gap point to overlooked potential, or is the market right to be so cautious? Look into how the SWS DCF model arrives at its fair value. Simply Wall St performs a discounted cash flow (DCF) on every stock in the world every day (check out Cabaletta Bio for example). We show the entire calculation in full. You can track the result in your watchlist or portfolio and be alerted when this changes, or use our stock screener to discover undervalued stocks based on their cash flows. If you save a screener we even alert you when new companies match - so you never miss a potential opportunity. If you see things differently or want to dig deeper into the data, you can quickly craft your own take in just a few minutes with Do it your way. A great starting point for your Cabaletta Bio research is our analysis highlighting 1 key reward and 5 important warning signs that could impact your investment decision. Stay ahead of the curve by expanding your portfolio beyond the obvious. Smart moves now could set you up for the gains others miss out on later. Capture the potential of strong returns by targeting undervalued opportunities. Start with these 890 undervalued stocks based on cash flows to find stocks trading at prices below their intrinsic value. Power up your watchlist with high-yield choices and grow your income stream with these 19 dividend stocks with yields > 3% offering standout dividend payers. Tap into the innovation shaping industries by checking out these 24 AI penny stocks that harness artificial intelligence for the next wave of growth. 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 CABA. Have feedback on this article? Concerned about the content? Get in touch with us directly. Alternatively, email [email protected]

– Registrational cohort enrollment in RESET-Myositis™ trial on track to start in 2H25 with anticipated 2027 BLA submission for rese-cel in myositis – – Five disease-specific cohorts fully enrolled in the RESET™ clinical development program from over 70 clinical sites as of July 31, 2025, with expansion phase enrollment continuing – – FDA meetings to align on the next wave of registrational cohorts for rese-cel anticipated in 3Q25 for lupus, 4Q25 for systemic sclerosis and 1H26 for myasthenia gravis – – Rese-cel clinical data presented at the EULAR 2025 Congress reinforce compelling clinical responses with nearly all patients off immunomodulatory medications and steroids; favorable risk-benefit profile observed across myositis, lupus and systemic sclerosis patients – – Closed $100 million public offering to support late clinical-stage development and commercial readiness activities for rese-cel; cash runway extended into 2H26 – PHILADELPHIA, Aug. 07, 2025 (GLOBE NEWSWIRE) -- Cabaletta Bio, Inc. (Nasdaq: CABA), a clinical-stage biotechnology company focused on developing and launching the first curative targeted cell therapies designed specifically for patients with autoimmune diseases, today reported financial results for the second quarter ended June 30, 2025, and provided a business update. “We achieved significant progress advancing rese-cel in the first half of 2025, including aligning with the FDA on a registrational pathway for rese-cel in myositis to support an anticipated 2027 first BLA submission. We also presented new data that reinforce the therapeutic potential of rese-cel across several autoimmune diseases,” said Steven Nichtberger, M.D., Chief Executive Officer of Cabaletta. “As our early clinical data are emerging, enrollment in dermatomyositis, scleroderma and myasthenia gravis has been particularly robust. We look forward to building on this momentum by initiating the myositis registrational program, obtaining regulatory alignment on registrational pathways for two additional indications this year and presenting new clinical data at multiple scientific meetings in the second half of 2025, including complete Phase 1/2 data from RESET-Myositis as well as initial clinical data from RESET-PV™ evaluating rese-cel without pre-conditioning.” Recent Operational Highlights and Upcoming Anticipated Milestones Rese-cel: Rese-cel (resecabtagene autoleucel, formerly CABA-201) is an investigational, autologous CAR-T cell therapy engineered with a fully human CD19 binder and a 4-1BB co-stimulatory domain, designed specifically for the treatment of autoimmune diseases. Administered as a single, weight-based infusion, rese-cel is intended to transiently and deeply deplete CD19-positive cells, with the goal of resetting the immune system and achieving durable clinical responses without the need for chronic therapy. Cabaletta is evaluating rese-cel in the RESET (REstoring SElf-Tolerance) clinical development program, which includes multiple ongoing company-sponsored trials across a diverse and growing range of autoimmune diseases in rheumatology, neurology and dermatology. Clinical Development New clinical and translational data presented at the EULAR 2025 Congress: In June 2025, Cabaletta presented new clinical and translational data from 18 evaluable patients in the ongoing RESET-Myositis, RESET-SLE™ and RESET-SSc™ trials in three oral presentations at the EULAR 2025 Congress. The data supported the ability of rese-cel to generate deep B cell depletion and compelling clinical responses in these patients, with nearly all patients off immunomodulators and steroids through the follow-up period. On track to initiate enrollment in myositis registrational cohorts: Cabaletta plans to initiate enrollment in two open-label, single-arm, registrational myositis cohorts consisting of approximately 15 patients each in the second half of 2025. Upcoming anticipated clinical data presentations in 2025 and 2026: In the second half of 2025, Cabaletta plans to present complete Phase 1/2 clinical data from the RESET-Myositis trial, initial dose data from the RESET-PV trial, which is evaluating rese-cel without preconditioning in patients with pemphigus vulgaris (PV), and initial clinical data from the RESET-MG™ trial. Additionally, Cabaletta expects to present complete Phase 1/2 clinical data from the RESET-SLE and RESET-SSc trials in the first half of 2026. Regulatory First BLA submission planned in 2027 for myositis following FDA alignment on key registrational design elements: In May 2025, Cabaletta announced alignment with the U.S. Food and Drug Administration (FDA) on key design elements for two registrational cohorts in the RESET-Myositis trial. The cohort comprised of patients with dermatomyositis or antisynthetase syndrome represents about 85% of the myositis population, while the IMNM cohort represents about 15%. The two cohorts are independent of each other with regards to regulatory considerations, although as agreed with FDA, safety data from all rese-cel patients will be used to support the Biologics License Application (BLA). The Company plans to submit its first BLA for rese-cel in myositis in 2027 based on either cohort, if successful. Additional regulatory discussions planned with FDA to align on additional registrational cohort designs: Cabaletta plans to meet with the FDA to align on key registrational design elements for the RESET-SLE trial in 3Q25, the RESET-SSc trial in 4Q25 and the RESET-MG trial in 1H26. Manufacturing Advancing CMC commercial supply readiness and innovation activities: To support commercial supply readiness, Cabaletta has been advancing BLA-enabling activities both lentiviral vector process and cellular drug product process. The Oxford Biomedica lentiviral process and the commercial drug product process, which has been transferred to Lonza, will be used for initiating registrational enrollment. Corporate Updates In June 2025, Cabaletta closed an underwritten public offering consisting of shares of its common stock, pre-funded warrants and accompanying common stock warrants. The net proceeds from the offering were approximately $94 million, after deducting underwriting discounts, commissions and offering expenses payable by the Company. Second Quarter 2025 Financial Results Research and development expenses were $37.6 million for the three months ended June 30, 2025, compared to $23.4 million for the same period in 2024. General and administrative expenses were $8.3 million for the three months ended June 30, 2025, compared to $6.9 million for the same period in 2024. As of June 30, 2025, Cabaletta had cash, cash equivalents and short-term investments of $194.7 million, compared to $164.0 million as of December 31, 2024. The Company expects that its cash position as of June 30, 2025, will enable it to fund its operating plan into the second half of 2026. About Cabaletta Bio Cabaletta Bio (Nasdaq: CABA) is a clinical-stage biotechnology company focused on developing and launching the first curative targeted cell therapies designed specifically for patients with autoimmune diseases. The CABA™ platform encompasses two complementary strategies which aim to advance the discovery and development of engineered T cell therapies with the potential to become deep and durable, perhaps curative, treatments for a broad range of autoimmune diseases. The lead CARTA (Chimeric Antigen Receptor T cells for Autoimmunity) strategy is prioritizing the development of rese-cel, a 4-1BB-containing fully human CD19-CAR T cell investigational therapy. Rese-cel is currently being evaluated in the RESET™ (REstoring SElf-Tolerance) clinical development program spanning multiple therapeutic areas, including rheumatology, neurology and dermatology. Cabaletta Bio’s headquarters and labs are located in Philadelphia, PA. For more information, please visit www.cabalettabio.com and connect with us on LinkedIn. Forward-Looking Statements This press release contains “forward-looking statements” of Cabaletta Bio within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including without limitation, express or implied statements regarding: Cabaletta’s business plans and objectives as a whole; Cabaletta’s ability to realize its vision of launching the first curative targeted cell therapy designed specifically for patients with autoimmune diseases; Cabaletta’s ability to successfully complete research and further development and commercialization of its drug candidates in current or future indications, including the timing and results of Cabaletta’s clinical trials and its ability to conduct and complete clinical trials; expectation that clinical results will support rese-cel’s safety and activity profile; statements regarding the timing of interactions with regulatory authorities, including such authorities’ review of safety information from Cabaletta’s ongoing clinical trials and potential registrational pathway for rese-cel; Cabaletta’s ability to leverage its emerging clinical data and its efficient development strategy; Cabaletta’s belief that its new data reinforces the therapeutic potential of rese-cel across several autoimmune diseases; the clinical significance of the clinical data read-out at upcoming scientific meetings and timing thereof; Cabaletta’s belief that it has obtained alignment with FDA on the registrational path for rese-cel; Cabaletta’s expectations around the potential success and therapeutic benefits of rese-cel; the Company’s advancement of separate Phase 1/2 clinical trials of rese-cel in patients with SLE, myositis, SSc and gMG and advancement of the RESET-PV and RESET-MS trials, including updates related to status, safety data, efficiency of clinical trial design and timing of data read-outs or otherwise; Cabaletta’s ability to expand its clinical supply for registrational trial(s) across the RESET clinical development program as well as to expand its manufacturing options for rese-cel; Cabaletta’s ability to increase enrollment in its US and Europe clinical networks; Cabaletta’s plans to initiate enrollment in two open-label, single-arm, registrational myositis cohorts consisting of approximately 15 patients each in the second half of 2025; Cabaletta’s plans to meet with the FDA to discuss registrational cohorts for rese-cel and the timing thereof; Cabaletta’s expectations surrounding the anticipated initiation of three new registrational cohorts, potential BLA submission and timing thereof; and Cabaletta’s use of capital, expense and other financial results in the future and its ability to fund operations into the second half of 2026. Any forward-looking statements in this press release are based on management’s current expectations and beliefs of future events and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. These risks and uncertainties include, but are not limited to: risks related to regulatory filings and potential clearance; the risk that signs of biologic activity or persistence may not inform long-term results; Cabaletta’s ability to demonstrate sufficient evidence of safety, efficacy and tolerability in its preclinical studies and clinical trials of rese-cel; the risk that the results observed with the similarly-designed construct employed in academic publications, including due to the dosing regimen, are not indicative of the results we seek to achieve with rese-cel; risks that modifications to trial design or approach may not have the intended benefits and that the trial design may need to be further modified; risks related to clinical trial site activation, delays in enrollment generally or enrollment rates that are lower than expected; delays related to assessment of clinical trial results; risks related to unexpected safety or efficacy data observed during clinical studies; risks related to volatile market and economic conditions and public health crises; Cabaletta’s ability to retain and recognize the intended incentives conferred by Orphan Drug Designation and Fast Track Designation or other designations for its product candidates, as applicable; risks related to Cabaletta’s ability to protect and maintain its intellectual property position; risks related to fostering and maintaining successful relationships with Cabaletta’s collaboration and manufacturing partners; uncertainties related to the initiation and conduct of studies and other development requirements for its product candidates; the risk that any one or more of Cabaletta’s product candidates will not be successfully developed and/or commercialized; and the risk that the initial or interim results of preclinical studies or clinical studies will not be predictive of future results in connection with future studies. For a discussion of these and other risks and uncertainties, and other important factors, any of which could cause Cabaletta’s actual results to differ from those contained in the forward-looking statements, see the section entitled “Risk Factors” in Cabaletta’s most recent annual report on Form 10-K as well as discussions of potential risks, uncertainties, and other important factors in Cabaletta’s other subsequent filings with the Securities and Exchange Commission. All information in this press release is as of the date of the release, and Cabaletta undertakes no duty to update this information unless required by law. Contacts: Anup Marda Chief Financial Officer [email protected]

– FDA meeting to align on myositis registrational trial designs for rese-cel in 1H25 on track – – Enrolling approximately one patient per week across the RESET™ clinical development program since ACR Convergence presentation in November 2024 with 33 patients enrolled across 56 active clinical trial sites in the U.S. & Europe as of March 14, 2025 – – Clinical and translational data on rese-cel to be presented in three oral presentations at the EULAR 2025 Congress in June – – Operational runway into 1H26 with cash and cash equivalents of $164.0 million as of December 31, 2024 – PHILADELPHIA, March 31, 2025 (GLOBE NEWSWIRE) -- Cabaletta Bio, Inc. (Nasdaq: CABA), a clinical-stage biotechnology company focused on developing and launching the first curative targeted cell therapies designed specifically for patients with autoimmune diseases, today reported financial results for the fourth quarter and full year ended December 31, 2024, and provided a business update. “We are looking forward to meeting with the FDA to align on registrational trial designs in myositis, which affects approximately 70,000 patients in the U.S., by leveraging our emerging clinical data and our efficient development strategy. Since presenting clinical and translational data from the RESET program demonstrating that a single weight-based dose of rese-cel was able to provide potentially transformative clinical responses after discontinuation of all immunosuppressants and while off or tapering off steroids, we have seen robust physician and patient interest in the RESET clinical program,” said Steven Nichtberger, M.D., Chief Executive Officer of Cabaletta. “In addition, we are advancing innovations that have the potential to enhance the patient and physician experience, including an apheresis-free approach and evaluation of a RESET-PV™ cohort with no preconditioning.” Recent Operational Highlights and Upcoming Anticipated Milestones Rese-cel (resecabtagene autoleucel, formerly referred to as CABA-201): Autologous, engineered T cells designed with a chimeric antigen receptor containing a fully human CD19 binder and a 4-1BB co-stimulatory domain infused as a single weight-based dose as a potential treatment for a broad range of autoimmune diseases where B cells contribute to the initiation and/or maintenance of disease. Rheumatology Portfolio Systemic sclerosis (SSc) In March 2025, Cabaletta learned of an important protocol deviation in the RESET-SSc trial. The protocol requires that in any patient with a fever or infection during the two weeks prior to rese-cel infusion the investigator promptly discuss the appropriateness and timing of infusion with the trial’s Medical Monitor. In this case, the patient reported a fever three days prior to infusion. The Cabaletta Medical Monitor was not notified prior to the site infusing the patient. Nine days following rese-cel infusion, the patient experienced a dose-limiting toxicity of grade 3 immune effector cell-associated neurotoxicity syndrome (ICANS) based on a transient period of confusion. There was no cerebral edema, seizures or motor dysfunction associated with the ICANS event and the patient was arousable throughout. The ICANS resolved rapidly following treatment with dexamethasone and the patient was discharged without further symptoms. After data review, the Independent Data Monitoring Committee recommended that the trial proceed at the current dose without delay and endorsed Cabaletta’s proposal to require investigators to affirmatively confirm in writing to the company the absence of fevers or evidence of infection in patients during the two weeks prior to rese-cel infusion. In February 2025, Cabaletta announced the first patient dosed with rese-cel in the severe skin cohort of the RESET-SSc™ trial continued to demonstrate clinically meaningful skin improvements across several body areas at three months post-infusion, in addition to improvement in lung function, after discontinuing all disease-specific therapies. Myositis (idiopathic inflammatory myopathies, IIM) In February 2025, Cabaletta announced the first adult dermatomyositis patient maintained a major total improvement score (TIS) improvement at three months post-infusion, off all immunosuppressants and tapering steroids, showing the potential for patients with refractory myositis to achieve drug-free remission. In addition, initial clinical responses in the first two immune-mediated necrotizing myopathy (IMNM) patients continued to show gradual improvement, consistent with published academic data, suggesting response kinetics may differ among myositis subtypes. In January 2025, Cabaletta announced the first juvenile myositis clinical site in the RESET-Myositis™ trial is open and actively recruiting. The U.S. Food and Drug Administration (FDA) previously granted Rare Pediatric Disease designation for rese-cel in juvenile dermatomyositis. Systemic lupus erythematosus (SLE) and lupus nephritis (LN) In February 2025, Cabaletta announced three out of four patients in the SLE cohort of the RESET-SLE™ trial achieved DORIS (definition of remission in SLE) remission. In addition, the first patient dosed with rese-cel in the lupus nephritis (LN) cohort of the same trial achieved a complete renal response (CRR). All 6 SLE and LN patients dosed, including these patients, demonstrated clinical responses, including improvements on the SLEDAI-2K score and/or urine protein-creatinine ratio, while off all immunosuppressants and steroids as of the data cut-off date of January 8, 2025. Neurology Portfolio Generalized myasthenia gravis (gMG) In January 2025, Cabaletta announced the first patient has been enrolled in the RESET-MG™ trial, evaluating rese-cel in patients with myasthenia gravis. Multiple sclerosis (MS) In January 2025, Cabaletta announced the Investigational New Drug (IND) application for rese-cel has been allowed to proceed within the routine 30-day window by the FDA for the RESET-MS™ trial, a Phase 1/2 study evaluating rese-cel in patients with multiple sclerosis. In addition, the FDA has granted Fast Track Designation to rese-cel for the treatment of relapsing and progressive forms of MS. Dermatology Portfolio Pemphigus vulgaris (PV) In January 2025, Cabaletta announced the first patient has been enrolled in the RESET-PV™ trial, evaluating rese-cel without preconditioning in patients with PV. Upcoming External Scientific Presentations In June 2025, Cabaletta plans to present new and updated clinical and translational data on rese-cel from the RESET-Myositis, RESET-SLE and RESET-SSc trials in three oral presentations at the upcoming EULAR 2025 Congress, which is being held at Fira de Barcelona in Barcelona, Spain from June 11-14, 2025. Corporate Updates In March 2025, Cabaletta and Cellares announced the successful conclusion of the Technology Adoption Program on Cellares’ automated cell therapy manufacturing Cell Shuttle™, facilitating the potential integration of the Cell Shuttle into Cabaletta’s clinical and commercial, if approved, manufacturing strategy for rese-cel. In January 2025, Cabaletta announced an expanded Contract Development and Manufacturing Organization (CDMO) agreement with Lonza to supply rese-cel clinical product under current Good Manufacturing Practices as soon as the second half of 2025. This expanded CDMO agreement is intended to address the increasing pace of enrollment in clinical trials evaluating rese-cel as well as to prepare for registrational trial(s) across the RESET clinical development program. Fourth Quarter and Full Year 2024 Financial Results Research and development expenses were $25.5 million and $97.2 million for the three months ended December 31, 2024, and the full year ended December 31, 2024, respectively, compared to $17.4 million and $55.4 million for the three months ended December 31, 2023, and the full year ended December 31, 2023, respectively. General and administrative expenses were $8.3 million and $27.9 million for the three months ended December 31, 2024, and the full year ended December 31, 2024, respectively, compared to $5.7 million and $19.2 million for the three months ended December 31, 2023, and the full year ended December 31, 2023, respectively. As of December 31, 2024, Cabaletta had cash, cash equivalents and short-term investments of $164.0 million, compared to $241.2 million as of December 31, 2023. The Company expects that its cash and cash equivalents as of December 31, 2024, will enable it to fund its operating plan into the first half of 2026. About rese-cel (formerly referred to as CABA-201)Rese-cel is a 4-1BB-containing fully human CD19-CAR T cell investigational therapy for patients with autoimmune diseases where B cells contribute to the initiation and/or maintenance of disease. Following a one-time infusion of a weight-based dose, rese-cel is designed to transiently and deeply deplete all CD19-positive cells in both the peripheral circulation and within tissues. We believe this approach has the potential to reset the immune system and result in profound clinical responses without chronic therapy requirements in patients. Cabaletta is currently evaluating rese-cel in the RESET™ (REstoring SElf-Tolerance) clinical development program which includes multiple disease-specific, company-sponsored clinical trials across expanding portfolios of autoimmune diseases in a broad range of therapeutic areas, including rheumatology, neurology and dermatology. About Cabaletta BioCabaletta Bio (Nasdaq: CABA) is a clinical-stage biotechnology company focused on developing and launching the first curative targeted cell therapies designed specifically for patients with autoimmune diseases. The CABA™ platform encompasses two complementary strategies which aim to advance the discovery and development of engineered T cell therapies with the potential to become deep and durable, perhaps curative, treatments for a broad range of autoimmune diseases. The lead CARTA (Chimeric Antigen Receptor T cells for Autoimmunity) strategy is prioritizing the development of rese-cel, a 4-1BB-containing fully human CD19-CAR T cell investigational therapy. Rese-cel is currently being evaluated in the RESET™ (REstoring SElf-Tolerance) clinical development program spanning multiple therapeutic areas, including rheumatology, neurology and dermatology. Cabaletta Bio’s headquarters and labs are located in Philadelphia, PA. For more information, please visit www.cabalettabio.com and connect with us on LinkedIn. Forward-Looking StatementsThis press release contains “forward-looking statements” of Cabaletta Bio within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including without limitation, express or implied statements regarding: Cabaletta’s business plans and objectives as a whole; Cabaletta’s ability to realize its vision of launching the first curative targeted cell therapy designed specifically for patients with autoimmune diseases; Cabaletta’s ability to successfully complete research and further development and commercialization of its drug candidates in current or future indications, including the timing and results of Cabaletta’s clinical trials and its ability to conduct and complete clinical trials; expectation that clinical results will support rese-cel’s safety and activity profile; statements regarding the timing of interactions with regulatory authorities, including such authorities’ review of safety information from Cabaletta’s ongoing clinical trials and potential registrational pathway for rese-cel; Cabaletta’s ability to leverage its emerging clinical data and its efficient development strategy; Cabaletta’s belief that the pace of enrollment in each of the RESET clinical cohorts is providing early insight into the most compelling rese-cel use cases for physicians and their patients; Cabaletta’s ability to develop innovations that can enhance the patient and physician experience; Cabaletta’s belief that rese-cel is a one-time treatment that can potentially free patients from their autoimmune disease; Cabaletta’s expectations around the potential success and therapeutic benefits of rese-cel, including its belief that rese-cel has the potential to reset the immune system and result in profound clinical responses without chronic therapy requirements in patients; the Company’s advancement of separate Phase 1/2 clinical trials of rese-cel in patients with SLE, myositis, SSc and gMG and advancement of the RESET-PV and RESET-MS trials, including updates related to status, safety data, efficiency of clinical trial design and timing of data read-outs or otherwise; Cabaletta’s ability to expand its clinical supply for registrational trial(s) across the RESET clinical development program as well as to expand its manufacturing options for rese-cel; Cabaletta’s ability to increase enrollment in its US and Europe clinical networks; Cabaletta’s ability to leverage its growing clinical trial network to accelerate development of its therapy for patients and to generate clinical and translational data; Cabaletta’s plans to meet with the FDA to discuss registrational trials; and Cabaletta’s use of capital, expense and other financial results in the future and its ability to fund operations into the first half of 2026. Any forward-looking statements in this press release are based on management’s current expectations and beliefs of future events and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. These risks and uncertainties include, but are not limited to: risks related to regulatory filings and potential clearance; the risk that signs of biologic activity or persistence may not inform long-term results; Cabaletta’s ability to demonstrate sufficient evidence of safety, efficacy and tolerability in its preclinical studies and clinical trials of rese-cel; the risk that the results observed with the similarly-designed construct employed in academic publications, including due to the dosing regimen, are not indicative of the results we seek to achieve with rese-cel; risks that modifications to trial design or approach may not have the intended benefits and that the trial design may need to be further modified; risks related to clinical trial site activation, delays in enrollment generally or enrollment rates that are lower than expected; delays related to assessment of clinical trial results; risks related to unexpected safety or efficacy data observed during clinical studies; risks related to volatile market and economic conditions and public health crises; Cabaletta’s ability to retain and recognize the intended incentives conferred by Orphan Drug Designation and Fast Track Designation or other designations for its product candidates, as applicable; risks related to Cabaletta’s ability to protect and maintain its intellectual property position; risks related to fostering and maintaining successful relationships with Cabaletta’s collaboration and manufacturing partners; uncertainties related to the initiation and conduct of studies and other development requirements for its product candidates; the risk that any one or more of Cabaletta’s product candidates will not be successfully developed and/or commercialized; and the risk that the initial or interim results of preclinical studies or clinical studies will not be predictive of future results in connection with future studies. For a discussion of these and other risks and uncertainties, and other important factors, any of which could cause Cabaletta’s actual results to differ from those contained in the forward-looking statements, see the section entitled “Risk Factors” in Cabaletta’s most recent annual report on Form 10-K as well as discussions of potential risks, uncertainties, and other important factors in Cabaletta’s other subsequent filings with the Securities and Exchange Commission. All information in this press release is as of the date of the release, and Cabaletta undertakes no duty to update this information unless required by law. Contacts:Anup MardaChief Financial [email protected]