Regeneron’s siRNA Therapy to Myasthenia Gravis Delivers in Phase III Trial

When designing an inhibitory drug, is the absolute maximum achievable inactivation of a therapeutic target always necessary?

For Regeneron Pharmaceuticals, the Phase III NIMBLE trial of its siRNA therapy targeting complement component 5 (C5), cemdisiran, in generalized myasthenia gravis (gMG) suggests the answer may be no. In fact, in some cases, incomplete inhibition may even be better.

In patients with gMG—an autoimmune disorder that affects the neuromuscular junction, eroding muscle control—less than complete inhibition of innate immunity’s complement system with cemdisiran proved not only sufficient but also outperformed the combination therapy of the siRNA and an antibody for C5, pozelimab, which achieved greater inhibition. Regeneron announced that cemdisiran monotherapy every th