Cartesian Therapeutics Announces FDA Special Protocol Assessment Agreement for Phase 3 AURORA Trial of Descartes-08 in Myasthenia Gravis

Cartesian Therapeutics, Inc. recently announced it has received written agreement from the US FDA under the Special Protocol Assessment (SPA) process on the overall design of the Company’s planned Phase 3 AURORA trial for Descartes-08, its lead mRNA cell therapy candidate, in myasthenia gravis (MG). 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.

“This SPA agreement marks an important milestone in the development of Descartes-08 for MG, providing critical regulatory clarity and a clear path toward potential approval,” said Carsten Brunn, PhD, President and Chief Executive Officer of Cartesian. “Supported by compelling Phase 2b results where we observed deep and durable improvements in patients with MG, we firmly believe that Descartes-08 has the potential to serve as a meaningful new therapy that can be delivered in the convenient outpatient setting without the need for preconditioning chemotherapy. We look forward to commencing the Phase 3 AURORA trial in the first half of this year.”

 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 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-ADL score of three points or more at Month 4 compared to placebo.

In December 2024, the Company announced positive updated results from the Phase 2b trial of Descartes-08 in participants with MG. Deepening responses were observed over time, with Descartes-08-treated participants included in the primary efficacy dataset (n=12) experiencing an average MG Activities of Daily Living (MG-ADL) reduction of 5.5 (±1.1) at Month 4. Consistent with previously reported data, Descartes-08 was observed to be well-tolerated, supporting outpatient administration without the need for lymphodepleting chemotherapy.

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.

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.

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 in Phase 2b 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. The Company’s clinical-stage pipeline also includes Descartes-15, a next-generation, autologous anti-BCMA mRNA CAR-T. For more information, visit www.cartesiantherapeutics.com.