Cartesian Therapeutics Reports Strong 12-Month Data For Lead Cell Therapy In Myasthenia Gravis Patients

Cartesian Therapeutics, Inc. RNAC on Tuesday revealed 12-month efficacy and safety data from the Phase 2b trial of Descartes-08, lead cell therapy candidate, in participants with generalized myasthenia gravis (MG).

MG is a chronic autoimmune disorder that causes muscle weakness and fatigue. The disease is characterized by antibodies against the acetylcholine receptor, a protein found on the surface of nerve cells that plays a key role in muscle contraction.

As previously announced, the trial met its primary endpoint and demonstrated a safety profile supporting outpatient administration of Descartes-08.

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.

Participants treated with Descartes-08 were observed to have deep responses following initial treatment and sustained symptom improvement, with an average MG Activities of Daily Living (MG-ADL, score to assess impact on daily functions) 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.

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The subset of participants who had not been exposed to prior biologic therapies exhibited 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 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.

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.

Cartesian remains on track to commence the Phase 3 AURORA trial of Descartes-08 in MG in the second quarter of 2025.

RNAC Price Action: Cartesian Therapeutics stock is down 3.56% at $9.75 at publication Tuesday.

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