Cartesian Therapeutics Announces Additional Retreatment Data for Descartes-08 Highlighting Deep and Durable Responses in Patients with Myasthenia Gravis

FDA agreement on the Phase 3 trial design’s suitability to support a future license application remains subject to the trial’s outcome.

Rhea-AI Summary

Cartesian Therapeutics (RNAC) reported 12-month Descartes-08 retreatment results in five patients with generalized myasthenia gravis.

After symptoms recurred following initial treatment, patients received six weekly infusions. At Month 12 after retreatment, mean MG-ADL and MGC scores had fallen 6.6 (±4.2) and 15 (±6.2) points from baseline, respectively. Four patients maintained a clinically meaningful MG-ADL improvement through Month 12. No serious adverse events were reported during retreatment. Cartesian expects topline results from its Phase 3 AURORA trial in the first quarter of 2027 and a biologics license application filing in mid-2027.

7 points · 0 major

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0 major · 3 points

Hollow bars mark forward-looking points. How the balance works

Positive

• Moderate pointFDA agreement found the Phase 3 AURORA trial design acceptable to support a future license application, subject to the trial outcome.
• Minor pointMG-ADL scores fell a mean 6.6 (±4.2) points from baseline at Month 12 after retreatment.
• Minor pointMGC scores fell a mean 15 (±6.2) points from baseline at Month 12 after retreatment.
• Minor pointAll five patients met clinically meaningful improvement thresholds; four maintained MG-ADL improvement through Month 12.
• Minor pointNo serious adverse events were reported during retreatment; no new safety signals were reported.

2 minor points

• Minor point. Forward-looking: it has not happened yet and may not happen.Cartesian expects Phase 3 topline data in the first quarter of 2027.
• Minor point. Forward-looking: it has not happened yet and may not happen.Cartesian expects a biologics license application filing in mid-2027.

Negative

• Minor pointSymptoms recurred after initial treatment in the five patients who received retreatment.
• Minor pointFive patients make up this retreatment case series; Phase 3 results remain pending.
• Minor pointFDA agreement on the trial design’s suitability to support a future application remains subject to the trial outcome.

Key Figures

Retreated patients: 5 patients Median retreatment interval: 16.6 months MG-ADL reduction: 6.6 (±4.2) points +5 more

Retreated patients

5 patients

Descartes-08 retreatment analysis

Median retreatment interval

16.6 months

Between completion of initial course and first retreatment infusion

MG-ADL reduction

6.6 (±4.2) points

Mean reduction from baseline at Month 12 after retreatment

MGC reduction

15 (±6.2) points

Mean reduction from baseline at Month 12 after retreatment

Patients maintaining meaningful MG-ADL reduction

4 patients

Through Month 12 following retreatment

Retreatment regimen

6 once-weekly infusions

Descartes-08 retreatment course

AURORA topline data

1Q27

Phase 3 trial in myasthenia gravis

BLA filing

Mid-2027

Expected filing for Descartes-08 in myasthenia gravis

Key Terms

mg-adl, car-t, cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, +2 more

6 terms

mg-adl medical

"Myasthenia Gravis Activities of Daily Living [MG-ADL] ≥6"

MG-ADL is a short, self-reported checklist that measures how the neuromuscular disease myasthenia gravis affects basic daily activities like talking, chewing, breathing, and walking. Investors pay attention because changes on this scale are commonly used as a clinical trial endpoint and a practical signal of patient benefit; clearer improvement can boost a treatment’s chances of regulatory approval, uptake by doctors, and commercial value—like a thermometer showing clinical impact.

car-t technical

"autologous anti-B cell maturation antigen (BCMA) chimeric antigen receptor T-cell therapy (CAR-T)"

CAR-T is a type of cancer therapy that reprograms a patient’s own immune cells to seek and destroy specific cancer cells, like teaching guard dogs a new scent to track intruders. It matters to investors because CAR-T treatments can command high prices, drive strong revenue for successful developers, and carry regulatory and manufacturing risks that can sharply affect a company’s valuation and long-term growth prospects.

cytokine release syndrome medical

"no cases of cytokine release syndrome (CRS)"

An intense immune overreaction in which the body's defense system releases a large surge of signaling proteins, causing fever, low blood pressure, breathing trouble or organ stress; imagine the immune system's alarm going into overdrive and flooding the body with emergency responders. Investors care because this side effect can slow or block regulatory approval, increase clinical trial costs and liabilities, limit how widely a therapy can be used, and therefore affect a drug's market value and sales potential.

immune effector cell-associated neurotoxicity syndrome medical

"immune effector cell-associated neurotoxicity syndrome (ICANS)"

immune effector cell-associated neurotoxicity syndrome (ICANS) is a brain-related side effect that can occur after treatments that activate powerful immune cells, such as engineered cell therapies. It can cause confusion, speech problems, seizures or coma when the immune response unintentionally harms brain function; think of an overenthusiastic security system that starts damaging the house it’s protecting. Investors care because ICANS affects clinical trial results, regulatory approvals, product labeling, treatment adoption, monitoring costs and potential liability, all of which influence a therapy’s commercial value.

biologics license application regulatory

"support a future biologics license application (BLA)"

A biologics license application is a formal request submitted to regulatory authorities seeking approval to market a new biological medicine, such as vaccines or treatments made from living organisms. It is a comprehensive review process that evaluates the safety, effectiveness, and manufacturing quality of the product. For investors, receiving approval signals that a biological therapy can be sold to the public, potentially leading to revenue growth and market success.

special protocol assessment regulatory

"under the Special Protocol Assessment (SPA) process"

A special protocol assessment is a formal, written agreement between a drug or device developer and a health regulator about the design, size and analysis plans of a pivotal clinical trial or study. It matters to investors because it reduces regulatory uncertainty—like getting a signed blueprint before building—by signaling that if the study follows the agreed plan and meets its goals, the regulator is unlikely to reject the results solely for design reasons, though it does not guarantee approval.

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Descartes–08 demonstrated improvement in mean change from baseline in MG-ADL following initial treatment and retreatment; mean MG-ADL reduction of 6.6 points at Month 12 following retreatment

Median interval between end of initial treatment course and first retreatment infusion was 16.6 months

No new safety signals reported; safety profile consistent with previously reported data

Topline data from Phase 3 AURORA trial of Descartes-08 in patients with myasthenia gravis expected in 1Q27

FREDERICK, Md., Sept. 29, 2026 (GLOBE NEWSWIRE) -- Cartesian Therapeutics, Inc. (NASDAQ: RNAC) (the “Company” or “Cartesian”), a late clinical-stage biotechnology company pioneering cell therapy for autoimmune diseases, today announced additional positive retreatment data of its lead investigational asset, Descartes-08, in patients with generalized myasthenia gravis (MG), being presented today during the Myasthenia Gravis Foundation of America (MGFA) Scientific Session of the 2026 American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM) Annual Meeting being held in Orlando, Florida.

Descartes-08 is Cartesian’s autologous anti-B cell maturation antigen (BCMA) chimeric antigen receptor T-cell therapy (CAR-T) in clinical development for MG and myositis. Dr. James F. Howard Jr., M.D., a distinguished neurologist at the University of North Carolina School of Medicine and investigator in the Phase 2b trial, will present the case series of five retreated patients who experienced clinically meaningful improvements in MG severity scores following a recurrence of MG symptoms at least 12 months after the initial course of Descartes-08 treatment.

“There remains a significant unmet need for patients suffering from MG today where current treatment options require patients to utilize chronic immunosuppressants to manage the disease,” said James F. Howard, Jr., M.D., Cartesian Clinical Advisor and Professor of Neurology, Medicine, and Allied Health at the University of North Carolina School of Medicine. “Descartes-08 is designed to target BCMA+ immune cells in MG to potentially provide patients with sustained symptom improvement reflected in clinically significant MG-ADL reductions with the added ability to be re-dosed if symptoms recur. For patients who have already cycled through multiple therapies, the option to retreat a CAR-T cell therapy, in an outpatient setting and without lymphodepleting chemotherapy, represents an exciting potential advancement in the field of MG.”

12-Month Retreatment Results

The data presented today at AANEM analyzed the efficacy, safety, and durability of Descartes-08 retreatment in five patients with MG who previously received a full treatment course in the Phase 2 portion of the trial and experienced recurrence of symptoms (Myasthenia Gravis Activities of Daily Living [MG-ADL] ≥6) following 12-month follow-up. Similar to the initial course of treatment, retreatment consisted of six once-weekly Descartes-08 infusions. Clinical outcomes were assessed by mean change in Myasthenia Gravis Composite (MGC) and MG-ADL scores from baseline through Month 12. Safety and tolerability were also assessed across treatment courses.​ Patients had a mean disease duration of 13 years with extensive treatment histories.

Efficacy

• Patients retreated (n=5) at a median of 16.6 months following completion of initial treatment course experienced greater improvement in MG symptoms compared to initial course of treatment; mean decrease in MG-ADL scores were sustained through 12 months following retreatment
  • Retreated patients observed an average MG-ADL reduction of 6.6 (±4.2) points from baseline at Month 12.
  • Retreated patients observed an average MGC reduction of 15 (±6.2) points from baseline at Month 12.
  • All retreated patients experienced a clinically meaningful reduction across MGC (≥3-point reduction) and MG-ADL scores (≥2-point reduction), and four patients maintained the clinically meaningful MG-ADL reduction through Month 12 following retreatment.
    
    

Safety

• Consistent safety data observed to date supports potential retreatment of Descartes-08 following recurrence of MG symptoms, as clinical benefit was observed with no new safety concerns
  • Descartes-08 was observed to be generally well-tolerated through Month 12 following retreatment, and adverse events were transient and mild. No serious adverse events were reported during retreatment. Notably, there were no cases of cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), cytopenias, or hypogammaglobulinemia.
    
    

“Descartes-08’s clinical data generated to date has demonstrated the potential for meaningful clinical responses that persist through 12 months following the completion of an initial course of treatment, with the ability to be re-dosed if needed. Unlike currently approved therapies that generally require cyclical dosing to maintain effect, Descartes-08 is being developed with the goal of providing sustained clinical benefit following a finite course of treatment.,” said Carsten Brunn, Ph.D., President and Chief Executive Officer of Cartesian. “We believe the combination of sustained symptom improvement, the ability to retreat if symptoms return, and the quality-of-life benefits of outpatient administration without lymphodepleting chemotherapy sets Descartes-08 apart and has the potential to meaningfully change the way MG is treated. These data strengthen our conviction in Descartes-08 as we approach topline results from our Phase 3 AURORA trial, expected in the first quarter of 2027.”

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 (BLA) in MG, subject to the ultimate outcome of the trial. Cartesian remains on track to readout topline data from its Phase 3 AURORA trial of Descartes-08 in MG in the first quarter of 2027, with a BLA filing expected in mid-2027.

About Descartes-08

Descartes-08, Cartesian’s lead cell therapy candidate, is an investigational, autologous CAR-T product targeting BCMA in clinical development for generalized MG and myositis, specifically dermatomyositis and antisynthetase syndrome. 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 late clinical-stage company pioneering cell therapy for the treatment of autoimmune diseases. The Company’s lead asset, Descartes-08, is a CAR-T in Phase 3 clinical development for patients with generalized myasthenia gravis, Phase 2 clinical development in myositis, specifically dermatomyositis and antisynthetase syndrome, and in Phase 1/2 clinical development for pediatric autoimmune diseases, including juvenile dermatomyositis. For more information, please visit www.cartesiantherapeutics.com or follow the Company on LinkedIn or X.

Forward Looking Statements

Any statements in this press release about the future expectations, plans and prospects of the Company, including without limitation, 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, or any of the Company’s other product candidates to treat MG, juvenile MG, myositis, juvenile dermatomyositis, or any other disease, the anticipated timing or the outcome of ongoing and planned clinical trials, studies and data readouts, including the ongoing Phase 3 AURORA trial of Descartes-08 in MG, the ongoing Phase 2 TRITON trial of Descartes-08 in myositis, and the ongoing Phase 1/2 HELIOS pediatric trial of Descartes-08 in autoimmune diseases, including juvenile dermatomyositis, the anticipated timing or the outcome of the FDA’s review of the Company’s regulatory filings, including the number of trials that may be necessary in order to obtain marketing approval, the potential for in-vivo delivery of the Company’s product candidates, 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 ability of the Company to enter into and maintain potential collaborations or partnerships, 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, pandemics, and macroeconomic impacts, 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.

Contact Information:
Investor Contact:
Megan LeDuc
Associate Director, Investor Relations
megan.leduc@cartesiantx.com

Media Contact:
David Rosen
Argot Partners
david.rosen@argotpartners.com

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What did Cartesian Therapeutics report after Descartes-08 retreatment for myasthenia gravis?

At Month 12 after retreatment, mean MG-ADL scores were 6.6 (±4.2) points below baseline and mean MGC scores were 15 (±6.2) points below baseline. Four of the five retreated patients maintained a clinically meaningful MG-ADL improvement through Month 12.

How was Descartes-08 retreatment given in Cartesian Therapeutics’ myasthenia gravis study?

Retreatment consisted of six once-weekly infusions. The five patients had experienced symptom recurrence after the initial course and 12-month follow-up. The median interval from completion of initial treatment to the first retreatment infusion was 16.6 months.