Descartes‑08 is an investigational, autologous, B‑cell maturation antigen (BCMA)–directed mRNA chimeric antigen receptor T‑cell (CAR‑T) therapy developed by Cartesian Therapeutics. It is being evaluated primarily for acetylcholine receptor antibody–positive generalized myasthenia gravis (gMG), as well as other autoimmune disorders. The therapy uses a patient’s own T cells and transient mRNA expression rather than an integrating vector, an approach intended to provide controlled CAR activity without permanent genomic modification.[5]
Mechanism and Administration
Descartes‑08 targets BCMA-expressing plasma cells and related antibody-producing cells that contribute to pathogenic autoantibody production in gMG. Because CAR expression is transient, the treatment does not require lymphodepleting chemotherapy. Clinical studies have administered the therapy as six once-weekly outpatient infusions. [1]
Clinical Evidence
In a randomized, double-blind, placebo-controlled Phase 2b trial involving 36 participants with gMG, Descartes‑08 met the study’s primary endpoint and demonstrated a safety profile supportive of outpatient administration. At 12 months, treated participants had an average 4.8-point improvement in Myasthenia Gravis Activities of Daily Living (MG‑ADL) score. Among participants without prior biologic therapy, the average improvement was 7.1 points, and 57% maintained minimal symptom expression. [1,2]
Company-reported retreatment data from five patients whose symptoms recurred after an initial response suggest that repeat administration may restore clinical benefit. Retreatment occurred a median of 16.6 months after the original course. At 12 months after retreatment, the mean improvements were 6.6 points on MG‑ADL and 15 points on the Myasthenia Gravis Composite. All five patients achieved clinically meaningful improvement, and four maintained the MG‑ADL benefit through Month 12. No new safety signals or serious adverse events were reported in this small case series. These findings are preliminary and do not establish an FDA-approved retreatment schedule. [3]
Regulatory and Development Status
Descartes‑08 remains investigational and has not been approved by the U.S. Food and Drug Administration (FDA). The FDA has granted the program Regenerative Medicine Advanced Therapy and Orphan Drug designations for myasthenia gravis, as well as Rare Pediatric Disease designation for juvenile dermatomyositis. 5 The Phase 3 AURORA trial (NCT06799247) is evaluating Descartes‑08 in approximately 100 adults with anti-AChR–positive gMG. ClinicalTrials.gov listed the study as active, not recruiting, as of September 1, 2026. [4]
Article by Kathy Clark, RN, BSN, CMCN, RIT, Vice President, Director of Managed Care. For more information about how the impact on your plan, please contact your Summit ReSources care specialist. The following sources were used as reference material for this article:
Vu, T., et al. (2026). BCMA-directed mRNA CAR T cell therapy for myasthenia gravis: A randomized, double-blind, placebo-controlled phase 2b trial. Nature Medicine. https://doi.org/10.1038/s41591-025-04171-y
Cartesian Therapeutics. (2025, April 8). Descartes‑08 observed to provide deep and sustained benefits through Month 12 after a single course of therapy in Phase 2b myasthenia gravis trial. Company news release
Howard, J. F., Jr., et al. (2026, September 29). Durability of response following retreatment with Descartes‑08 in generalized myasthenia gravis: A case series with 12-month follow-up [Conference presentation]. 2026 MGFA Scientific Session at AANEM. Presentation deck
ClinicalTrials.gov. (2026). Investigating an mRNA CAR T-cell therapy, known as Descartes‑08, as a potential approach to treat myasthenia gravis (NCT06799247). Study record
Cartesian Therapeutics. (2026). Pipeline: Descartes‑08. Company pipeline