Regeneron Targets gMG Approval for Cemdisiran After Phase III Success

Regeneron plans to seek regulatory approval for cemdisiran in generalised myasthenia gravis (gMG) after the siRNA therapy met primary and secondary endpoints in the Phase III NIMBLE trial (NCT05070858). The study assessed adults with anti-AChR antibodies, representing around 80% of the gMG population. Cemdisiran achieved a placebo-adjusted -2.3 change in MG-ADL scores, surpassing AstraZeneca’s Soliris and Ultomiris, as well as UCB’s Zilbrysq, though not exceeding UCB’s Rystiggo.

The drug also improved QMG scores by -4.24, supporting its efficacy as a standalone therapy, potentially avoiding risks linked to complement 5 inhibition. While two deaths occurred in the study’s extension phase, none were attributed to treatment in the placebo-controlled period.

If approved, cemdisiran would be the first siRNA therapy for gMG, offering patients the advantage of monthly dosing. However, Regeneron faces strong competition from FcRn blockers such as J&J’s Imaavy and Argenx’s Vyvgart, alongside AstraZeneca’s emerging pipeline candidate gefurulimab.

29-08-2025