Selecta Biosciences, Inc.

After a single course of therapy, Descartes-08-treated participants were observed to sustain deep responses through long-term follow-up, with an average 4.8-point reduction in MG-ADL at Month 12 Deepest and most compelling sustained responses observed in Descartes-08-treated participants who did not have prior exposure to biologic therapies, with an average 7.1-point reduction in MG-ADL and 57% of patients in this subgroup maintaining minimum symptom expression at Month 12 Safety profile consistent with previously reported data and continues to support outpatient administration Phase 3 AURORA trial on track to dose first patient in 2Q25 FREDERICK, Md., April 08, 2025 (GLOBE NEWSWIRE) -- Cartesian Therapeutics, Inc. (NASDAQ: RNAC) (the “Company”), a clinical-stage biotechnology company pioneering cell therapy for autoimmune diseases, today announced 12-month efficacy and safety data from the Phase 2b trial of Descartes-08 in participants with generalized myasthenia gravis (MG). Participants dosed with a single six-week course of treatment of Descartes-08 were observed to continue to experience a sustained benefit in symptoms of MG at the 12-month assessment. The data will be discussed by management at the 24th Annual Needham Virtual Healthcare Conference today, April 8, 2025, and presented tomorrow, April 9, 2025, by Tuan Vu, M.D., Professor of Neurology at the University of South Florida Morsani College of Medicine, at the 2025 American Academy of Neurology Annual Meeting being held in San Diego. Descartes-08, Cartesian’s lead cell therapy candidate, is an autologous engineered chimeric antigen receptor T-cell therapy (CAR-T) product candidate targeting B-cell maturation antigen (BCMA). Descartes-08 is designed to be administered without preconditioning chemotherapy in an outpatient setting and does not use integrating vectors. 12-Month Phase 2b Trial Results In the Phase 2b double-blind, placebo-controlled, crossover trial, a total of 36 heavily pretreated, highly symptomatic participants with MG were randomized 1:1 to receive either Descartes-08 or placebo administered as six weekly outpatient infusions without preconditioning chemotherapy. As previously announced, the trial met its primary endpoint and demonstrated a safety profile supporting outpatient administration of Descartes-08. In December 2024, the Company reported updated efficacy and safety data from the trial in which deepening responses were observed over time and some participants were observed to have durable responses through to Month 12. The primary efficacy dataset for the follow-up portion of the trial consisted of a modified intent-to-treat (mITT) population of all subjects enrolled at academic medical centers who received at least one dose of Descartes-08 and completed at least one post-Month 3 MG Activities of Daily Living (MG-ADL) score follow-up assessment. As of a March 31, 2025 cutoff date, 12 out of 15 participants who received Descartes-08 in the primary efficacy dataset completed their Month 12 follow-up assessments. Three participants, two of whom were MG Composite (MGC) responders at Month 3, were lost to follow-up after their Month 3 assessments. 12-Month Efficacy Results Deep and sustained responses observed through Month 12 (n=12). Participants treated with Descartes-08 were observed to have deep responses following initial treatment and sustained symptom improvement, with an average MG-ADL reduction of 5.5 (±1.1) at Month 4 and 4.8 (±1.4) at Month 12. Participants treated with Descartes-08 were observed to have an average Quantitative Myasthenia Gravis Score (QMG) reduction of 4.8 (±1.7) points at Month 4, which deepened through Month 12 (6.0±2.1). 33% (4/12) of participants achieved minimum symptom expression (MSE), defined as an MG-ADL score of 0 or 1, at Month 6, all of whom maintained MSE through Month 12. 83% (10/12) of evaluable participants maintained a clinically meaningful response through Month 12. Clinically meaningful response is defined as a reduction in MG-ADL score of at least 2 points. Deepest and most compelling sustained responses observed in participants without prior biologic therapies (n=7). The subset of participants who did not have exposure to prior biologic therapies, including complement or neonatal fragment crystallizable receptor (FcRn) inhibitors, were observed to exhibit a deepening of responses throughout the year, with an average MG-ADL reduction of 6.6 (±1.5) at Month 4 and 7.1 (±1.9) at Month 12. The participants treated with Descartes-08 without exposure to prior biologic therapies were observed to have an average QMG reduction of 5.9 (±2.4) points at Month 4, which deepened through Month 12 (9.4±2.6). 57% (4/7) of these participants were observed to achieve MSE at Month 6 which was maintained through Month 12. 100% (7/7) of these participants were observed to maintain at least a clinically meaningful response through Month 12. Participants treated with Descartes-08 were observed to have deep responses following initial treatment and sustained symptom improvement, with an average MG-ADL reduction of 5.5 (±1.1) at Month 4 and 4.8 (±1.4) at Month 12. Participants treated with Descartes-08 were observed to have an average Quantitative Myasthenia Gravis Score (QMG) reduction of 4.8 (±1.7) points at Month 4, which deepened through Month 12 (6.0±2.1). 33% (4/12) of participants achieved minimum symptom expression (MSE), defined as an MG-ADL score of 0 or 1, at Month 6, all of whom maintained MSE through Month 12. 83% (10/12) of evaluable participants maintained a clinically meaningful response through Month 12. Clinically meaningful response is defined as a reduction in MG-ADL score of at least 2 points. The subset of participants who did not have exposure to prior biologic therapies, including complement or neonatal fragment crystallizable receptor (FcRn) inhibitors, were observed to exhibit a deepening of responses throughout the year, with an average MG-ADL reduction of 6.6 (±1.5) at Month 4 and 7.1 (±1.9) at Month 12. The participants treated with Descartes-08 without exposure to prior biologic therapies were observed to have an average QMG reduction of 5.9 (±2.4) points at Month 4, which deepened through Month 12 (9.4±2.6). 57% (4/7) of these participants were observed to achieve MSE at Month 6 which was maintained through Month 12. 100% (7/7) of these participants were observed to maintain at least a clinically meaningful response through Month 12. Safety Well-tolerated safety profile supports outpatient administration without the need for lymphodepleting chemotherapy. Consistent with previously reported data, Descartes-08 was observed to be well-tolerated across the safety dataset through Month 12 (n=12), and adverse events were transient and mostly mild, with no new adverse events reported in the 12-month follow-up data. Notably, there were no cases of cytokine release syndrome (CRS), and no cases of immune effector cell-associated neurotoxicity syndrome (ICANS). In addition, treatment with Descartes-08 was not observed to lead to a decrease in vaccine titers for common viruses and was not associated with increased rates of infection or hypogammaglobulinemia. There were no Descartes-08-related adverse events reported in Month 4 through Month 12 follow-up. As previously reported, common side effects through the Month 3 primary endpoint observed in participants who received any dose of Descartes-08 were infusion-related reactions manifesting as fever (60% of participants receiving Descartes-08), chills (60% of participants receiving Descartes-08), headache (55% of participants receiving Descartes-08) and nausea (45% of participants receiving Descartes-08), all of which typically resolved within 24 hours of infusion. Consistent with previously reported data, Descartes-08 was observed to be well-tolerated across the safety dataset through Month 12 (n=12), and adverse events were transient and mostly mild, with no new adverse events reported in the 12-month follow-up data. Notably, there were no cases of cytokine release syndrome (CRS), and no cases of immune effector cell-associated neurotoxicity syndrome (ICANS). In addition, treatment with Descartes-08 was not observed to lead to a decrease in vaccine titers for common viruses and was not associated with increased rates of infection or hypogammaglobulinemia. There were no Descartes-08-related adverse events reported in Month 4 through Month 12 follow-up. As previously reported, common side effects through the Month 3 primary endpoint observed in participants who received any dose of Descartes-08 were infusion-related reactions manifesting as fever (60% of participants receiving Descartes-08), chills (60% of participants receiving Descartes-08), headache (55% of participants receiving Descartes-08) and nausea (45% of participants receiving Descartes-08), all of which typically resolved within 24 hours of infusion. "This impressive data highlights the potential of Descartes-08 to serve as an important therapeutic option to deliver deep and sustained reductions in MG-ADL for patients with myasthenia gravis,” said Tuan Vu, M.D., Professor of Neurology at the University of South Florida Morsani College of Medicine, Division Director for Neuromuscular Medicine and EMG and investigator in the Phase 2b trial. “The data in participants who had not received prior biologic therapy is particularly striking as this population is most comparable to the patient populations in trials of standard-of-care biologics. Participants in this subgroup who were randomized to Descartes-08 were observed to experience a profound average 7.1-point reduction in MG-ADL and 57% these patients were observed to maintain MSE out to Month 12. I look forward to following the continued development of Descartes-08 in MG as it moves into the Phase 3 AURORA trial.” “The remarkable results presented today underscore the potential of utilizing our cell therapy to deliver deep and durable responses in MG patients one year after receiving a single course of therapy in a convenient outpatient setting with no preconditioning chemotherapy,” said Carsten Brunn, Ph.D., President and Chief Executive Officer of Cartesian. “The impressive strength and duration of response shown in the data reinforce our confidence in the potential of Descartes-08 to transform the current treatment landscape in MG, offering patients a safe, flexible, and durable treatment option. We look forward to dosing the first patient in our Phase 3 AURORA trial in the second quarter of this year.” Descartes-08 was previously granted Regenerative Medicine Advanced Therapy (RMAT) Designation and Orphan Drug Designation by the U.S. Food and Drug Administration (FDA) for the treatment of MG. Cartesian received written agreement from the FDA under the Special Protocol Assessment (SPA) process indicating the overall design of the planned Phase 3 AURORA trial of Descartes-08 is acceptable to support a future Biologics License Application in MG, subject to the ultimate outcome of the trial. Cartesian remains on track to commence the Phase 3 AURORA trial of Descartes-08 in MG in the second quarter of 2025. About Myasthenia Gravis Myasthenia gravis (MG) is a chronic autoimmune disorder that causes disabling muscle weakness and fatigue. For most people with MG, the disease is characterized by the presence of antibodies against the acetylcholine receptor, a protein found on the surface of nerve cells that plays a key role in muscle contraction. There is currently no cure for MG, and treatment typically requires chronic immunosuppressive medicines, with their attendant risks and side effects. About Descartes-08 Descartes-08, Cartesian’s lead cell therapy candidate, is an autologous chimeric antigen receptor T-cell therapy (CAR-T) product targeting B-cell maturation antigen (BCMA) in clinical development for generalized myasthenia gravis (MG) and systemic lupus erythematosus. In contrast to conventional DNA-based CAR T-cell therapies, Cartesian’s CAR-T administration is designed to not require preconditioning chemotherapy, can be administered in the outpatient setting, and does not carry the risk of genomic integration associated with cancerous transformation. Descartes-08 has been granted Orphan Drug Designation and Regenerative Medicine Advanced Therapy Designation by the U.S. Food and Drug Administration for the treatment of MG, and Rare Pediatric Disease Designation for the treatment of juvenile dermatomyositis. About Cartesian Therapeutics Cartesian Therapeutics is a clinical-stage company pioneering cell therapy for the treatment of autoimmune diseases. The Company’s lead asset, Descartes-08, is a CAR-T entering Phase 3 clinical development for patients with generalized myasthenia gravis and Phase 2 development for systemic lupus erythematosus, with a Phase 2 basket trial planned in additional autoimmune indications. A Phase 3 trial of Descartes-08 in patients with generalized myasthenia gravis has received written agreement from the FDA under the Special Protocol Assessment process. The Company’s clinical-stage pipeline also includes Descartes-15, a next-generation, autologous anti-BCMA CAR-T currently being evaluated in a Phase 1 trial in patients with multiple myeloma. For more information, please visit www.cartesiantherapeutics.com or follow the Company on LinkedIn or X, formerly known as Twitter. Forward Looking Statements Any statements in this press release about the future expectations, plans and prospects of the Company, including without limitation, statements regarding observations and data from the Company’s clinical trials of Descartes-08 in myasthenia gravis, the anticipated timing or the outcome of ongoing and planned clinical trials, studies and data readouts, the ability of the Company’s product candidates to be administered in an outpatient setting or without the need for preconditioning lymphodepleting chemotherapy, the potential of Descartes-08, Descartes-15, or any of the Company’s other product candidates to treat myasthenia gravis, systemic lupus erythematosus, juvenile dermatomyositis, or any other disease, the anticipated timing or the outcome of the FDA’s review of the Company’s regulatory filings, the Company’s ability to conduct its clinical trials and preclinical studies, the timing or making of any regulatory filings, the novelty of treatment paradigms that the Company is able to develop, the potential of any therapies developed by the Company to fulfill unmet medical needs, and enrollment in the Company’s clinical trials and other statements containing the words “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “hypothesize,” “intend,” “may,” “plan,” “potential,” “predict,” “project,” “should,” “target,” “would,” and similar expressions, constitute forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995. Actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors, including, but not limited to, the following: the uncertainties inherent in the initiation, completion and cost of clinical trials including proof of concept trials, including uncertain outcomes, the availability and timing of data from ongoing and future clinical trials and the results of such trials, whether preliminary results from a particular clinical trial will be predictive of the final results of that trial, whether results of early clinical trials will be indicative of the results of later clinical trials, and whether results observed in certain patient subgroups will be indicative of the results in such subgroups in later clinical trials or are reflective of a product candidate’s overall characteristics, the ability to predict results of studies performed on human beings based on results of studies performed on non-human subjects, the unproven approach of the Company’s technology, potential delays in enrollment of patients, undesirable side effects of the Company’s product candidates, its reliance on third parties to conduct its clinical trials, the Company’s inability to maintain its existing or future collaborations, licenses or contractual relationships, its inability to protect its proprietary technology and intellectual property, potential delays in regulatory approvals, the availability of funding sufficient for its foreseeable and unforeseeable operating expenses and capital expenditure requirements, the Company’s recurring losses from operations and negative cash flows, substantial fluctuation in the price of the Company’s common stock, risks related to geopolitical conflicts and pandemics and other important factors discussed in the “Risk Factors” section of the Company’s most recent Annual Report on Form 10-K and subsequently filed Quarterly Reports on Form 10-Q, and in other filings that the Company makes with the Securities and Exchange Commission. In addition, any forward-looking statements included in this press release represent the Company’s views only as of the date of its publication and should not be relied upon as representing its views as of any subsequent date. The Company specifically disclaims any intention to update any forward looking statements included in this press release, except as required by law. Investor Contact Megan LeDuc Associate Director of Investor Relations megan.leduc@cartesiantx.com Media Contact David Rosen Argot Partners david.rosen@argotpartners.com Source: Cartesian Therapeutics, Inc.

Phase 3 AURORA trial of Descartes-08 in myasthenia gravis on track to commence in 1H25; Deep and durable responses maintained over 12 months in Descartes-08-treated participants in Phase 2b trial Phase 2 trial of Descartes-08 in systemic lupus erythematosus ongoing with expected data readout in 2H25 Company expects to initiate Phase 2 pediatric basket trial of Decartes-08 in select autoimmune indications in 2H25 Dosing underway in first-in-human Phase 1 trial of Descartes-15 Approximately $214.3 million cash, cash equivalents and restricted cash as of December 31, 2024 expected to support planned operations into mid-2027, including completion of planned Phase 3 AURORA trial FREDERICK, Md., March 13, 2025 (GLOBE NEWSWIRE) -- Cartesian Therapeutics, Inc. (NASDAQ: RNAC) (the “Company”), a clinical-stage biotechnology company pioneering mRNA cell therapy for autoimmune diseases, today reported financial results for the full year ended December 31, 2024, and outlined recent corporate updates. “Following a year marked by tremendous progress, we remain committed to advancing our pipeline of mRNA cell therapies designed to be dosed in the convenient outpatient setting, without the need for preconditioning chemotherapy,” said Carsten Brunn, Ph.D., President and Chief Executive Officer of Cartesian. “Notably, we remain on track to commence our planned Phase 3 AURORA trial of Descartes-08 in patients with myasthenia gravis (MG) in the first half of this year. Supported by positive results from our Phase 2b trial demonstrating deep and durable improvements for Descartes-08-treated participants, along with our Special Protocol Assessment (SPA) agreement with U.S. Food and Drug Administration (FDA), we are confident that we have a clear path toward potential approval of this promising new therapy.” Dr. Brunn continued, “Beyond MG, we remain on track to report preliminary data from our ongoing Phase 2 open-label trial of Descartes-08 in patients with systemic lupus erythematosus (SLE) and expect to initiate our Phase 2 pediatric basket trial of Descartes-08 in select autoimmune diseases in the second half of this year. With these anticipated milestones, along with our strong balance sheet, we believe we are well-positioned to deliver on our mission to expand the reach of cell therapy to autoimmunity.” Recent Pipeline Progress and Anticipated Milestones Phase 3 AURORA Trial of Descartes-08 in MG on Track to Commence in the First Half of 2025. The randomized, double-blind, placebo-controlled Phase 3 AURORA trial is designed to assess Descartes-08 versus placebo (1:1 randomization) administered as six once weekly outpatient infusions without preconditioning chemotherapy in approximately 100 participants with acetylcholine receptor autoantibody positive (AChR Ab+) MG. The primary endpoint will assess the proportion of Descartes-08 participants with an improvement in MG Activities of Daily Living (MG-ADL) score of three points or more at Month 4 compared to placebo. Descartes-08, Cartesian’s lead product candidate, is an autologous anti-B cell maturation antigen (BCMA) mRNA-engineered chimeric antigen receptor T-cell therapy (mRNA CAR-T).In January 2025, Cartesian announced that it has received written agreement from the FDA under the SPA process on the overall design of the planned Phase 3 AURORA trial. The SPA agreement indicates that the FDA has determined that the proposed trial design is acceptable to support a future Biologics License Application for Descartes-08 in MG, subject to the ultimate outcome of the trial. Announced Positive Updated Results from Phase 2b Trial of Descartes-08 in Participants with MG, with Deepening Response Observed Over Time, Durable Through Month 12. In December 2024, the Company announced updated efficacy and safety data from the Phase 2b trial of Descartes-08 in participants with MG. Participants included in the primary efficacy dataset (n=12)1 experienced an average MG-ADL reduction of 5.5 (±1.1) at Month 4. Responses were observed to be durable through Month 12, with 80% (4/5) of evaluable participants from the primary efficacy dataset maintaining a clinically meaningful response, defined as a reduction in MG-ADL score of at least 2 points. Descartes-08 continues to be observed as well-tolerated, supporting outpatient administration without the need for lymphodepleting chemotherapy.Dr. Tuan Vu, one of Cartesian’s Clinical Advisors, will Present at the American Academy of Neurology Annual Meeting on April 9, 2025 at 1:12 pm PT. The presentation and abstract are titled, “The Efficacy and Safety of Autologous BCMA-directed mRNA CAR T-Cell Therapy in Generalized Myasthenia Gravis: Results from a Phase 2b Randomized Placebo-controlled Trial.”Preliminary Data from Ongoing Phase 2 Open-Label Trial of Descartes-08 in Patients with SLE Expected in the Second Half of 2025. The trial is designed to assess the safety, tolerability and clinical activity of outpatient Descartes-08 administration without preconditioning chemotherapy in patients with SLE. SLE is an incurable autoimmune disease marked by systemic inflammation that affects multiple organ systems and impacts approximately 1.5 million people in the United States.Phase 2 Pediatric Basket Trial of Descartes-08 in Select Autoimmune Diseases Expected to Initiate in the Second Half of 2025. This pediatric basket trial will target juvenile SLE, juvenile MG, juvenile dermatomyositis (JDM) and anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis. The FDA previously granted Rare Pediatric Disease Designation to Descartes-08 for the treatment of JDM, which is a rare pediatric autoimmune disorder. Dosing Ongoing in First-in-Human Phase 1 Clinical Trial of Descartes-15. The Phase 1 dose escalation trial of Cartesian’s next-generation, autologous anti-BCMA mRNA CAR-T cell therapy, is designed to assess the safety and tolerability of outpatient Descartes-15 administration in patients with multiple myeloma. Following the Phase 1 dose escalation trial, the Company expects to subsequently assess Descartes-15 in autoimmune indications. Corporate Updates Emily English Promoted to Chief Operations Officer. Emily English, formerly Cartesian’s Senior Vice President and Head of Manufacturing Operations, was promoted to Chief Operations Officer in January 2025. Emily’s significant contributions, including her leadership in the expansion of the new, state-of-the-art current good manufacturing practice (cGMP) facility in Frederick, Maryland, have been instrumental in Cartesian’s progress as the Company continues to advance its pipeline. Full Year 2024 Financial Results Cash, cash equivalents and restricted cash as of December 31, 2024 was $214.3 million and is expected to support planned operations, including completion of planned Phase 3 AURORA trial for Descartes-08 in MG, into mid-2027. Research and development expenses were $45.1 million for the year ended December 31, 2024, compared to $71.3 million for the year ended December 31, 2023. The decrease was primarily a result of the Company’s restructuring in 2023 prior to the merger between Cartesian and Selecta Biosciences, including reductions in expenses for preclinical and clinical programs due to the strategic reprioritization, stock compensation in connection with the Selecta Biosciences/ Cartesian Therapeutics merger, and higher expenses in 2023 compared to 2024 due to one-time cash charges related to salaries and benefits.General and administrative expenses were $30.1 million for the year ended December 31, 2024, compared to $40.5 million for the year ended December 31, 2023. The decrease in expense for the year ended December 31, 2024 was primarily the result of reductions in expenses incurred for stock compensation and professional fees in connection with the merger between Cartesian and Selecta Biosciences.Net loss was $(77.4) million, or $(4.48) net loss per share (basic), for the year ended December 31, 2024, compared to net loss of $(219.7) million, or $(49.76) net loss per share (basic), for the year ended December 31, 2023. About Descartes-08 Descartes-08, Cartesian’s lead mRNA cell therapy candidate, is an autologous mRNA-engineered chimeric antigen receptor T-cell therapy (mRNA CAR-T) product targeting B-cell maturation antigen (BCMA) in clinical development for generalized myasthenia gravis (MG) and systemic lupus erythematosus. In contrast to conventional DNA-based CAR T-cell therapies, mRNA CAR-T administration is designed to not require preconditioning chemotherapy, can be administered in the outpatient setting, and does not carry the risk of genomic integration associated with cancerous transformation. Descartes-08 has been granted Orphan Drug Designation and Regenerative Medicine Advanced Therapy Designation by the U.S. Food and Drug Administration for the treatment of MG, and Rare Pediatric Disease Designation for the treatment of juvenile dermatomyositis. About Descartes-15 Descartes-15 is a next-generation, autologous anti-BCMA mRNA CAR-T cell therapy. In preclinical studies, Descartes-15 has been observed to achieve an approximately ten-fold increase in CAR expression and selective target-specific killing, relative to Descartes-08. Similar to Descartes-08, Descartes-15 is designed to be administered without preconditioning chemotherapy and does not use integrating vectors. About Cartesian Therapeutics Cartesian Therapeutics is a clinical-stage company pioneering mRNA cell therapy for the treatment of autoimmune diseases. The Company’s lead asset, Descartes-08, is an mRNA CAR-T entering Phase 3 clinical development for patients with generalized myasthenia gravis and Phase 2 development for systemic lupus erythematosus, with a Phase 2 basket trial planned in additional autoimmune indications. A Phase 3 trial of Descartes-08 in patients with generalized myasthenia gravis has received written agreement from the FDA under the Special Protocol Assessment process. The Company’s clinical-stage pipeline also includes Descartes-15, a next-generation, autologous anti-BCMA mRNA CAR-T currently being evaluated in a Phase 1 trial in patients with multiple myeloma. For more information, please visit www.cartesiantherapeutics.com or follow the Company on LinkedIn or X, formerly known as Twitter. Forward Looking Statements Any statements in this press release about the future expectations, plans and prospects of the Company, including without limitation, statements regarding the Company’s expected cash resources and cash runway, the ability of the Company’s product candidates to be administered in an outpatient setting or without the need for preconditioning lymphodepleting chemotherapy, the potential of Descartes-08, Descartes-15, or any of the Company’s other product candidates to treat myasthenia gravis, juvenile myasthenia gravis, systemic lupus erythematosus, juvenile systemic lupus erythematosus, juvenile dermatomyositis, multiple myeloma, or any other disease, the amount and occurrence of any payments to holders of the Company’s contingent value rights, the anticipated timing or the outcome of ongoing and planned clinical trials, studies and data readouts, including the planned Phase 3 AURORA trial of Descartes-08 in myasthenia gravis, the planned Phase 2 pediatric basket trial of Descartes-08 in juvenile dermatomyositis, juvenile systemic lupus erythematosus, juvenile myasthenia gravis and other conditions, and the ongoing Phase 2 trial of Descartes-08 in systemic lupus erythematosus, the anticipated timing or the outcome of the FDA’s review of the Company’s regulatory filings, the Company’s ability to conduct its clinical trials and preclinical studies, the timing or making of any regulatory filings, the anticipated timing or outcome of selection of developmental product candidates, the novelty of treatment paradigms that the Company is able to develop, the potential of any therapies developed by the Company to fulfill unmet medical needs, and enrollment in the Company’s clinical trials and other statements containing the words “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “hypothesize,” “intend,” “may,” “plan,” “potential,” “predict,” “project,” “should,” “target,” “would,” and similar expressions, constitute forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995. Actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors, including, but not limited to, the following: the uncertainties inherent in the initiation, completion and cost of clinical trials including proof of concept trials, including uncertain outcomes, the availability and timing of data from ongoing and future clinical trials and the results of such trials, whether preliminary results from a particular clinical trial will be predictive of the final results of that trial and whether results of early clinical trials will be indicative of the results of later clinical trials, the ability to predict results of studies performed on human beings based on results of studies performed on non-human subjects, the unproven approach of the Company’s technology, potential delays in enrollment of patients, undesirable side effects of the Company’s product candidates, political uncertainty, the Company’s reliance on third parties to conduct its clinical trials, the Company’s inability to maintain its existing or future collaborations, licenses or contractual relationships, its inability to protect its proprietary technology and intellectual property, potential delays in regulatory approvals, the availability of funding sufficient for its foreseeable and unforeseeable operating expenses and capital expenditure requirements, the Company’s recurring losses from operations and negative cash flows, substantial fluctuation in the price of the Company’s common stock, risks related to geopolitical conflicts and pandemics and other important factors discussed in the “Risk Factors” section of the Company’s most recent Annual Report on Form 10-K and subsequently filed Quarterly Reports on Form 10-Q, and in other filings that the Company makes with the Securities and Exchange Commission. In addition, any forward-looking statements included in this press release represent the Company’s views only as of the date of its publication and should not be relied upon as representing its views as of any subsequent date. The Company specifically disclaims any intention to update any forward-looking statements included in this press release, except as required by law. Cartesian Therapeutics, Inc. and SubsidiariesConsolidated Balance Sheets(Amounts in thousands, except share data and par value) December 31, 2024 December 31, 2023Assets Current assets: Cash and cash equivalents$212,610 $76,911 Accounts receivable 872 5,870 Unbilled receivables — 2,981 Prepaid expenses and other current assets 3,144 4,967 Total current assets 216,626 90,729 Non-current assets: Property and equipment, net 9,912 2,113 Right-of-use asset, net 5,535 10,068 In-process research and development assets 150,600 150,600 Goodwill 48,163 48,163 Long-term restricted cash 1,669 1,377 Investments 2,000 2,000 Other assets 518 — Total assets$435,023 $305,050 Liabilities, convertible preferred stock, and stockholders’ deficit Current liabilities: Accounts payable$288 $3,150 Accrued expenses and other current liabilities 12,076 15,572 Lease liability 2,851 2,166 Deferred revenue — 2,311 Warrant liabilities — 720 Contingent value right liability 7,761 15,983 Forward contract liabilities — 28,307 Total current liabilities 22,976 68,209 Non-current liabilities: Lease liability, net of current portion 11,133 8,789 Deferred revenue, net of current portion — 3,538 Warrant liabilities, net of current portion 3,836 5,674 Contingent value right liability, net of current portion 387,739 342,617 Deferred tax liabilities, net 16,141 15,853 Total liabilities 441,825 444,680 Series A Preferred Stock, $0.0001 par value; no and 548,375 shares authorized as of December 31, 2024 and December 31, 2023, respectively; no and 435,120.513 shares issued and outstanding as of December 31, 2024 and December 31, 2023, respectively — 296,851 Options for Series A Preferred Stock — 3,703 Stockholders’ deficit: Series A Preferred Stock, $0.0001 par value; 134,904.563 and no shares authorized as of December 31, 2024 and December 31, 2023, respectively; 120,790.402 and no shares issued and outstanding as of December 31, 2024 and December 31, 2023, respectively — — Series B Preferred Stock, $0.0001 par value; 437,927 and no shares authorized as of December 31, 2024 and December 31, 2023, respectively; 437,927 and no shares issued and outstanding as of December 31, 2024 and December 31, 2023, respectively — — Preferred stock, $0.0001 par value; 9,427,168.437 and 9,451,625 shares authorized as of December 31, 2024 and December 31, 2023, respectively; no shares issued and outstanding as of December 31, 2024 and December 31, 2023 — — Common stock, $0.0001 par value; 350,000,000 shares authorized as of December 31, 2024 and December 31, 2023; 25,767,369 and 5,397,597 shares issued and outstanding as of December 31, 2024 and December 31, 2023, respectively 3 1 Additional paid-in capital 689,887 179,062 Accumulated deficit (692,071) (614,647)Accumulated other comprehensive loss (4,621) (4,600)Total stockholders’ deficit (6,802) (440,184)Total liabilities, convertible preferred stock, and stockholders’ deficit$435,023 $305,050 Cartesian Therapeutics, Inc. and Subsidiaries Consolidated Statements of Operations and Comprehensive Loss(Amounts in thousands, except share and per share data) Twelve Months EndedDecember 31, 2024 2023 Revenue: Collaboration and license revenue$38,275 $26,004 Grant revenue 638 — Total revenue 38,913 26,004 Operating expenses: Research and development 45,105 71,260 General and administrative 30,126 40,450 Impairment of long-lived assets 7,579 710 Total operating expenses 82,810 112,420 Operating loss (43,897) (86,416)Interest income 7,386 4,964 Foreign currency transaction, net — 38 Interest expense — (2,833)Change in fair value of warrant liabilities 2,558 12,746 Change in fair value of contingent value right liability (36,900) (18,300)Change in fair value of forward contract liabilities (6,890) (149,600)Other income, net 606 691 Loss before income taxes (77,137) (238,710)Income tax (expense) benefit (287) 19,000 Net loss$(77,424) $(219,710) Other comprehensive loss: Foreign currency translation adjustment (21) (53)Unrealized gain on marketable securities — 11 Total comprehensive loss$(77,445) $(219,752) Net loss per share allocable to common stockholders: Basic$(4.48) $(49.76)Diluted$(4.49) $(49.76)Weighted-average common shares outstanding: Basic 17,276,822 5,170,319 Diluted 17,357,943 5,170,319 Investor Contact Megan LeDucAssociate Director of Investor Relationsmegan.leduc@cartesiantx.com Media ContactDavid RosenArgot Partnersdavid.rosen@argotpartners.com 1 Primary efficacy dataset consisted of a modified intent-to-treat population of all subjects enrolled at academic medical centers who received at least one dose of Descartes-08 and completed at least one post-Month 3 MG-ADL score follow-up assessment.

Phase 3 AURORA trial of Descartes-08 in myasthenia gravis on track to commence in 1H25; Deep and durable responses maintained over 12 months in Descartes-08-treated participants in Phase 2b trial Phase 2 trial of Descartes-08 in systemic lupus erythematosus ongoing with expected data readout in 2H25 Company expects to initiate Phase 2 pediatric basket trial of Decartes-08 in select autoimmune indications in 2H25 Dosing underway in first-in-human Phase 1 trial of Descartes-15 Approximately $214.3 million cash, cash equivalents and restricted cash as of December 31, 2024 expected to support planned operations into mid-2027, including completion of planned Phase 3 AURORA trial FREDERICK, Md. , March 13, 2025 (GLOBE NEWSWIRE) -- Cartesian Therapeutics, Inc. (NASDAQ: RNAC) (the “Company”), a clinical-stage biotechnology company pioneering mRNA cell therapy for autoimmune diseases, today reported financial results for the full year ended December 31, 2024 , and outlined recent corporate updates. “Following a year marked by tremendous progress, we remain committed to advancing our pipeline of mRNA cell therapies designed to be dosed in the convenient outpatient setting, without the need for preconditioning chemotherapy,” said Carsten Brunn , Ph.D., President and Chief Executive Officer of Cartesian. “Notably, we remain on track to commence our planned Phase 3 AURORA trial of Descartes-08 in patients with myasthenia gravis (MG) in the first half of this year. Supported by positive results from our Phase 2b trial demonstrating deep and durable improvements for Descartes-08-treated participants, along with our Special Protocol Assessment (SPA) agreement with U.S. Food and Drug Administration (FDA), we are confident that we have a clear path toward potential approval of this promising new therapy.” Dr. Brunn continued, “Beyond MG, we remain on track to report preliminary data from our ongoing Phase 2 open-label trial of Descartes-08 in patients with systemic lupus erythematosus (SLE) and expect to initiate our Phase 2 pediatric basket trial of Descartes-08 in select autoimmune diseases in the second half of this year. With these anticipated milestones, along with our strong balance sheet, we believe we are well-positioned to deliver on our mission to expand the reach of cell therapy to autoimmunity.” Recent Pipeline Progress and Anticipated Milestones Phase 3 AURORA Trial of Descartes-08 in MG on Track to Commence in the First Half of 2025. The randomized, double-blind, placebo-controlled Phase 3 AURORA trial is designed to assess Descartes-08 versus placebo (1:1 randomization) administered as six once weekly outpatient infusions without preconditioning chemotherapy in approximately 100 participants with acetylcholine receptor autoantibody positive (AChR Ab+) MG. The primary endpoint will assess the proportion of Descartes-08 participants with an improvement in MG Activities of Daily Living (MG-ADL) score of three points or more at Month 4 compared to placebo. Descartes-08, Cartesian’s lead product candidate, is an autologous anti-B cell maturation antigen (BCMA) mRNA-engineered chimeric antigen receptor T-cell therapy (mRNA CAR-T).In January 2025 , Cartesian announced that it has received written agreement from the FDA under the SPA process on the overall design of the planned Phase 3 AURORA trial. The SPA agreement indicates that the FDA has determined that the proposed trial design is acceptable to support a future Biologics License Application for Descartes-08 in MG, subject to the ultimate outcome of the trial. Announced Positive Updated Results from Phase 2b Trial of Descartes-08 in Participants with MG, with Deepening Response Observed Over Time, Durable Through Month 12. In December 2024 , the Company announced updated efficacy and safety data from the Phase 2b trial of Descartes-08 in participants with MG. Participants included in the primary efficacy dataset (n=12)1 experienced an average MG-ADL reduction of 5.5 (±1.1) at Month 4. Responses were observed to be durable through Month 12, with 80% (4/5) of evaluable participants from the primary efficacy dataset maintaining a clinically meaningful response, defined as a reduction in MG-ADL score of at least 2 points. Descartes-08 continues to be observed as well-tolerated, supporting outpatient administration without the need for lymphodepleting chemotherapy. Dr. Tuan Vu , one of Cartesian’s Clinical Advisors , will Present at the American Academy of Neurology Annual Meeting on April 9, 2025 at 1:12 pm PT . The presentation and abstract are titled, “The Efficacy and Safety of Autologous BCMA-directed mRNA CAR T-Cell Therapy in Generalized Myasthenia Gravis: Results from a Phase 2b Randomized Placebo-controlled Trial.” Preliminary Data from Ongoing Phase 2 Open-Label Trial of Descartes-08 in Patients with SLE Expected in the Second Half of 2025. The trial is designed to assess the safety, tolerability and clinical activity of outpatient Descartes-08 administration without preconditioning chemotherapy in patients with SLE. SLE is an incurable autoimmune disease marked by systemic inflammation that affects multiple organ systems and impacts approximately 1.5 million people in the United States . Phase 2 Pediatric Basket Trial of Descartes-08 in Select Autoimmune Diseases Expected to Initiate in the Second Half of 2025. This pediatric basket trial will target juvenile SLE, juvenile MG, juvenile dermatomyositis (JDM) and anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis. The FDA previously granted Rare Pediatric Disease Designation to Descartes-08 for the treatment of JDM, which is a rare pediatric autoimmune disorder. Dosing Ongoing in First-in-Human Phase 1 Clinical Trial of Descartes-15. The Phase 1 dose escalation trial of Cartesian’s next-generation, autologous anti-BCMA mRNA CAR-T cell therapy, is designed to assess the safety and tolerability of outpatient Descartes-15 administration in patients with multiple myeloma. Following the Phase 1 dose escalation trial, the Company expects to subsequently assess Descartes-15 in autoimmune indications. Corporate Updates Emily English Promoted to Chief Operations Officer. Emily English , formerly Cartesian’s Senior Vice President and Head of Manufacturing Operations, was promoted to Chief Operations Officer in January 2025 . Emily’s significant contributions, including her leadership in the expansion of the new, state-of-the-art current good manufacturing practice (cGMP) facility in Frederick, Maryland , have been instrumental in Cartesian’s progress as the Company continues to advance its pipeline. Full Year 2024 Financial Results Cash, cash equivalents and restricted cash as of December 31, 2024 was $214.3 million and is expected to support planned operations, including completion of planned Phase 3 AURORA trial for Descartes-08 in MG, into mid-2027. Research and development expenses were $45.1 million for the year ended December 31, 2024 , compared to $71.3 million for the year ended December 31, 2023 . The decrease was primarily a result of the Company’s restructuring in 2023 prior to the merger between Cartesian and Selecta Biosciences , including reductions in expenses for preclinical and clinical programs due to the strategic reprioritization, stock compensation in connection with the Selecta Biosciences / Cartesian Therapeutics merger, and higher expenses in 2023 compared to 2024 due to one-time cash charges related to salaries and benefits. General and administrative expenses were $30.1 million for the year ended December 31, 2024 , compared to $40.5 million for the year ended December 31, 2023 . The decrease in expense for the year ended December 31, 2024 was primarily the result of reductions in expenses incurred for stock compensation and professional fees in connection with the merger between Cartesian and Selecta Biosciences . Net loss was $(77.4) million , or $(4.48) net loss per share (basic), for the year ended December 31, 2024 , compared to net loss of $(219.7) million , or $(49.76) net loss per share (basic), for the year ended December 31, 2023 . About Descartes-08 Descartes-08, Cartesian’s lead mRNA cell therapy candidate, is an autologous mRNA-engineered chimeric antigen receptor T-cell therapy (mRNA CAR-T) product targeting B-cell maturation antigen (BCMA) in clinical development for generalized myasthenia gravis (MG) and systemic lupus erythematosus. In contrast to conventional DNA-based CAR T-cell therapies, mRNA CAR-T administration is designed to not require preconditioning chemotherapy, can be administered in the outpatient setting, and does not carry the risk of genomic integration associated with cancerous transformation. Descartes-08 has been granted Orphan Drug Designation and Regenerative Medicine Advanced Therapy Designation by the U.S. Food and Drug Administration for the treatment of MG, and Rare Pediatric Disease Designation for the treatment of juvenile dermatomyositis. About Descartes-15 Descartes-15 is a next-generation, autologous anti-BCMA mRNA CAR-T cell therapy. In preclinical studies, Descartes-15 has been observed to achieve an approximately ten-fold increase in CAR expression and selective target-specific killing, relative to Descartes-08. Similar to Descartes-08, Descartes-15 is designed to be administered without preconditioning chemotherapy and does not use integrating vectors. About Cartesian Therapeutics Cartesian Therapeutics is a clinical-stage company pioneering mRNA cell therapy for the treatment of autoimmune diseases. The Company’s lead asset, Descartes-08, is an mRNA CAR-T entering Phase 3 clinical development for patients with generalized myasthenia gravis and Phase 2 development for systemic lupus erythematosus, with a Phase 2 basket trial planned in additional autoimmune indications. A Phase 3 trial of Descartes-08 in patients with generalized myasthenia gravis has received written agreement from the FDA under the Special Protocol Assessment process. The Company’s clinical-stage pipeline also includes Descartes-15, a next-generation, autologous anti-BCMA mRNA CAR-T currently being evaluated in a Phase 1 trial in patients with multiple myeloma. For more information, please visit www.cartesiantherapeutics.com or follow the Company on LinkedIn or X, formerly known as Twitter. Forward Looking Statements Any statements in this press release about the future expectations, plans and prospects of the Company, including without limitation, statements regarding the Company’s expected cash resources and cash runway, the ability of the Company’s product candidates to be administered in an outpatient setting or without the need for preconditioning lymphodepleting chemotherapy, the potential of Descartes-08, Descartes-15, or any of the Company’s other product candidates to treat myasthenia gravis, juvenile myasthenia gravis, systemic lupus erythematosus, juvenile systemic lupus erythematosus, juvenile dermatomyositis, multiple myeloma, or any other disease, the amount and occurrence of any payments to holders of the Company’s contingent value rights, the anticipated timing or the outcome of ongoing and planned clinical trials, studies and data readouts, including the planned Phase 3 AURORA trial of Descartes-08 in myasthenia gravis, the planned Phase 2 pediatric basket trial of Descartes-08 in juvenile dermatomyositis, juvenile systemic lupus erythematosus, juvenile myasthenia gravis and other conditions, and the ongoing Phase 2 trial of Descartes-08 in systemic lupus erythematosus, the anticipated timing or the outcome of the FDA’s review of the Company’s regulatory filings, the Company’s ability to conduct its clinical trials and preclinical studies, the timing or making of any regulatory filings, the anticipated timing or outcome of selection of developmental product candidates, the novelty of treatment paradigms that the Company is able to develop, the potential of any therapies developed by the Company to fulfill unmet medical needs, and enrollment in the Company’s clinical trials and other statements containing the words “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “hypothesize,” “intend,” “may,” “plan,” “potential,” “predict,” “project,” “should,” “target,” “would,” and similar expressions, constitute forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995. Actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors, including, but not limited to, the following: the uncertainties inherent in the initiation, completion and cost of clinical trials including proof of concept trials, including uncertain outcomes, the availability and timing of data from ongoing and future clinical trials and the results of such trials, whether preliminary results from a particular clinical trial will be predictive of the final results of that trial and whether results of early clinical trials will be indicative of the results of later clinical trials, the ability to predict results of studies performed on human beings based on results of studies performed on non-human subjects, the unproven approach of the Company’s technology, potential delays in enrollment of patients, undesirable side effects of the Company’s product candidates, political uncertainty, the Company’s reliance on third parties to conduct its clinical trials, the Company’s inability to maintain its existing or future collaborations, licenses or contractual relationships, its inability to protect its proprietary technology and intellectual property, potential delays in regulatory approvals, the availability of funding sufficient for its foreseeable and unforeseeable operating expenses and capital expenditure requirements, the Company’s recurring losses from operations and negative cash flows, substantial fluctuation in the price of the Company’s common stock, risks related to geopolitical conflicts and pandemics and other important factors discussed in the “Risk Factors” section of the Company’s most recent Annual Report on Form 10-K and subsequently filed Quarterly Reports on Form 10-Q, and in other filings that the Company makes with the Securities and Exchange Commission . In addition, any forward-looking statements included in this press release represent the Company’s views only as of the date of its publication and should not be relied upon as representing its views as of any subsequent date. The Company specifically disclaims any intention to update any forward-looking statements included in this press release, except as required by law. Investor Contact Megan LeDuc Associate Director of Investor Relations megan.leduc@cartesiantx.com Media Contact David Rosen Argot Partners david.rosen@argotpartners.com 1 Primary efficacy dataset consisted of a modified intent-to-treat population of all subjects enrolled at academic medical centers who received at least one dose of Descartes-08 and completed at least one post-Month 3 MG-ADL score follow-up assessment. Source: Cartesian Therapeutics, Inc.