Evaluate clinical outcomes with miv-cel in patients with gMG in Phase 2 of KYSA-6 (NCT06193889). 

gMG is a neuromuscular autoimmune disease typically causing substantial disability. Novel therapies that provide greater absolute reduction in MG Activities of Daily Living (MG-ADL) to minimize or eliminate disease symptoms are needed. Miv-cel is a fully human, autologous CD19 CAR T-cell therapy with CD28 costimulation, designed for potency and tolerability. 

Adults (18-75y) with gMG (MGFA class IIb-IV), history of AChR or MuSK autoantibodies, MG-ADL score ≥6, and ≥2 immunosuppressant/immunomodulator failures, received low-dose lymphodepletion and a single infusion of 1×10⁸ CAR T cells.

As of February 25, 2026, 7 patients were dosed (mean [range]: age 46.1y [21-62]; MG-ADL 10.6 [7-16]; quantitative MG [QMG] 16.9 [9-28]). Median follow-up was 10.2 months (range, 3.3-16.0). All patients had robust CAR T-cell expansion and B-cell depletion. With a single dose, all patients had ≥3-point MG-ADL improvement versus baseline; 57% achieved minimal symptom expression (MG-ADL ≤1) at their last follow-up. At 24-weeks (n=6), miv-cel treatment resulted in 8.5-point (range, 7-13) and 11.3-point (range, 5-27) mean reductions from baseline in MG-ADL and QMG scores, respectively. All 7 patients became immunotherapy-free (86% at last follow-up). No ICANS or high-grade CRS occurred.

These findings support the potential of a single dose of miv-cel to deliver durable, drug-free, disease-free remission in patients with moderate to severe gMG. Miv-cel treatment resulted in robust, sustained improvements in disease severity with an acceptable safety profile, and eliminated background immunosuppressants in the majority of patients. Phase 3 is ongoing.