#4-50E. Redefining Complement Inhibition: Cemdisiran Monotherapy in Generalized Myasthenia Gravis (Lancet, 2026)

Is complete complement inhibition truly necessary for managing generalized myasthenia gravis, or can we achieve optimal outcomes with a safer, partial blockade? In this episode, we explore the NIMBLE phase 3 trial, which investigated the efficacy and safety of cemdisiran, a C5-targeted siRNA, administered as a monotherapy and in combination with pozelimab. The study demonstrated that cemdisiran monotherapy significantly improved MG-ADL scores compared to placebo. The most groundbreaking finding of this research is that partial complement inhibition—approximately 77%—is sufficient to provide robust clinical efficacy. This shifts the paradigm, suggesting that complete complement blockade may not be required for this disease. However, when critically appraising this study, clinicians should note that the trial was not statistically powered to formally test the superiority of cemdisiran monotherapy directly against the combination therapy. For practicing physicians, this study is highly relevant as it introduces a novel therapeutic option: a subcutaneous injection required only once every three months, which not only reduces the treatment burden for patients but also minimizes the risk of severe infections like meningococcal disease.

Citation: Vu T, ..., Pavani R. Efficacy and safety of cemdisiran siRNA in myasthenia gravis (NIMBLE): a double-blind, randomised, placebo-controlled, phase 3 trial. The Lancet. 2026. DOI: 10.1016/S0140-6736(26)00690-2

Disclaimer: This audio summary is based on personal interpretation and does not guarantee the exact content of the original paper. Please refer to the original article for details.