Regeneron announces Phase 3 NIMBLE trial met primary, key secondary endpoints

Regeneron (REGN) Pharmaceuticals announced that the primary and key secondary endpoints were met in the Phase 3 NIMBLE trial assessing investigational cemdisiran monotherapy in adults with generalized myasthenia gravis, gMG. Cemdisiran is an siRNA that reduces circulating levels of complement factor 5 and, as monotherapy in this trial, was associated with an average of 74% inhibition of complement activity. The trial also assessed a combination of cemdisiran and pozelimab, a C5 antibody; this combination, which resulted in nearly 99% inhibition of complement activity, also met the primary and key secondary endpoints, though cemdisiran monotherapy was numerically better across these endpoints. Across all arms, treatment-emergent adverse events occurred in 69% of patients treated with cemdisiran, 81% with cemdi-poze, and 77% with placebo. Serious TEAEs occurred in 3% of patients treated with cemdisiran, 9% with cemdi-poze and 14% with placebo. Detailed results from the NIMBLE trial will be presented at an upcoming medical meeting. The U.S. regulatory application for cemdisiran is planned for the first quarter of 2026, pending discussions with the FDA.