FDA and EMA accept regulatory submissions for cemdisiran for the treatment of generalised myasthenia gravis

Regeneron Pharmaceuticals has recently announced that both the US FDA and the EMA have accepted regulatory applications for cemdisiran for the treatment of adults with generalised myasthenia gravis who test positive for anti-acetylcholine receptor antibodies. A Priority Review Voucher was applied to the New Drug Application, with the FDA targeting a decision in November 2026.

Both submissions draw on data from the Phase 3 NIMBLE trial, which assessed cemdisiran administered subcutaneously every 12 weeks in adults with symptomatic generalised myasthenia gravis, with standard of care immunosuppressants permitted at the treating clinician’s discretion. Among the largest interventional generalised myasthenia gravis trials ever conducted globally, NIMBLE’s complete dataset was published simultaneously in The Lancet and presented at the American Academy of Neurology Annual Meeting in April 2026.

Myasthenia gravis is a rare, lifelong autoimmune condition in which abnormal anti-acetylcholine receptor antibodies set off activation of the complement system, including C5, severing reliable communication between nerves and muscles and producing weakness that can be both debilitating and life-threatening. Globally, between 150 and 200 people in every million are estimated to live with the condition, with around 85,000 affected in the US alone. The disease tends to announce itself through ocular symptoms, yet close to 85% of those affected go on to experience involvement of additional muscle groups, at which point the condition is classified as generalised myasthenia gravis. At this stage, fatigue becomes profound and difficulties emerge across facial expression, speech, swallowing, and movement. Many patients with generalised myasthenia gravis continue to struggle with disease management, facing treatments that target symptoms rather than underlying mechanisms, the prolonged demands of immunosuppressant use, incomplete or declining responses, and a cumulative toll on their quality of life.

The safety and efficacy of cemdisiran in generalised myasthenia gravis remain under investigation and have not yet received full evaluation or approval from any regulatory authority.

Regeneron holds sole responsibility for the development, manufacture, and commercialisation of cemdisiran both as a standalone therapy and in combination with C5 antibodies, under a worldwide licensing arrangement with Alnylam.

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Cemdisiran, EMA, FDA, generalised myasthenia gravis, Regeneron Pharmaceuticals, regulatory submissions