FDA sets target date in November 2026 for cemdisiran for gMG

The FDA has accepted Regeneron’s new drug application for cemdisiran to treat adult patients with generalized myasthenia gravis (gMG). If approved, it will be indicated for patients who are anti-acetylcholine receptor (AChR) antibody-positive. The FDA will review the NDA under priority review with a target action date in November 2026, following use of a priority review voucher. A European application has also been accepted, with a decision anticipated in the second half of 2027.

Myasthenia gravis is a rare and chronic autoimmune disease that results in weakened voluntary muscles, particularly in the eyes, face, throat and limbs. Worldwide, an estimated 150 to 200 out of every million people have myasthenia gravis. In the United States, the disease impacts approximately 85,000 people, with the prevalence expected to rise to 88,000 by 2032.

Myasthenia gravis results in abnormal anti-AChR antibodies that activate the complement system and disrupt communication between nerves and muscles and results in debilitating and potentially life-threatening muscle weakness.

“Generalized myasthenia gravis is a chronic debilitating disease with unpredictable symptoms that impact daily life. While current therapies have managed disease activity, there remains an unmet need for options that achieve rapid and sustained efficacy with reduced treatment burden,” Tuan Vu, M.D., said in a news release in April 2026. Vu is a professor of Neurology at the University of South Florida Morsani College of Medicine and division director for Neuromuscular Medicine and EMG Laboratories.

Cemdisiran is an RNA interference (RNAi) therapeutic that targets the C5 component of the complement system, which is part of the innate immune system. C5 plays a critical role in inflammation and has been a target for autoimmune diseases. Cemdisiran was developed by Alnylam, and Regeneron has a license to develop and market cemdisiran as a monotherapy and in combination with other C5 antibodies.

The submission is supported by data from the phase 3 NIMBLE trial, which evaluated cemdisiran dosed subcutaneously every 12 weeks in adults with symptomatic gMG who may be receiving standard-of-care immunosuppressants.

In the trial, 284 patients were randomly assigned to receive cemdisiran monotherapy (79 patients), Veopoz (pozelimab) monotherapy (50 patients), combined cemdisiran and Veopoz (80 patients), or placebo (75 patients). The primary endpoint was change from baseline in Myasthenia Gravis-Activities of Daily Living (MG-ADL) scores at week 24. Veopoz is an approved Regeneron complement inhibitor to treat patients with CHAPLE disease, an ultra-rare and life-threatening hereditary immune disease.

In the intent-to-treat population, 64 patients who received cemdisiran alone experienced clinically meaningful improvements within two weeks on two assessment scales that measured changes from baseline in daily functions, such as talking, eating, breathing, vision and mobility, and muscle function, such as vision, speaking/swallowing and breathing.

One or more treatment-emergent adverse events occurred in 69.2% of patients receiving cemdisiran and 77.1% who received placebo. Most adverse events were mild-to-moderate in severity. The most common adverse events in patients receiving cemdisiran or placebo were worsening of MG, upper respiratory tract infection, urinary tract infection, nasopharyngitis, headache, rash, and diarrhea. No serious infections, meningococcal infections, or deaths occurred during the double-blind treatment period.

Full data from NIMBLE were simultaneously published in The Lancet and presented at the American Academy of Neurology (AAN) Annual Meeting in April 2026.

Regeneron is also developing cemdisiran in combination with Veopoz to treat patients with paroxysmal nocturnal hemoglobinuria (PNH), an ultra-rare blood disorder that is characterized by the destruction of red blood cells. Confirmatory phase 3 data are expected in late fourth quarter 2026.

The combination of cemdisiran and Veopoz is also being studied to treat patients with geographic atrophy, a leading cause of blindness in older patients. Interim data from a phase 3 lead-in trial are expected in the fourth quarter of 2026.