A new potential treatment for generalised myasthenia gravis (gMG), a rare and debilitating autoimmune neuromuscular disease, has shown promising results in a large international clinical trial. Gefurulimab, a C5 complement inhibitor developed by Alexion, AstraZeneca Rare Disease, met both its primary and all secondary endpoints in a Phase III study involving adults with anti-acetylcholine receptor (AChR) antibody-positive gMG.
The PREVAIL trial, which was randomised, double-blind, and placebo-controlled, demonstrated that patients treated with gefurulimab experienced a statistically significant and clinically meaningful improvement in symptoms, as measured by the Myasthenia Gravis Activities of Daily Living (MG-ADL) total score at 26 weeks. Improvements were also seen across all secondary measures.
gMG causes muscle weakness and fatigue due to an immune attack on the communication between nerves and muscles. Early symptoms can include slurred speech, drooping eyelids, and double vision. As the disease progresses, patients may experience difficulty swallowing, respiratory failure, and severe fatigue.
“Rapidly fluctuating symptoms and the unpredictable disability associated with gMG can affect nearly every aspect of a patient’s life,” said Dr. Kelly Gwathmey, Associate Professor of Neurology at Virginia Commonwealth University and a principal investigator in the study. “A once-weekly, self-administered C5 treatment option would offer patients greater convenience and independence in managing their condition.”
Marc Dunoyer, CEO of Alexion, added: “These positive results from the PREVAIL Phase III trial demonstrate the potential for gefurulimab to offer rapid and sustained disease control for this patient community. The data reinforce the established safety profile of C5 inhibition and support gefurulimab as a potential first-line biologic.”
Gefurulimab was well tolerated, with no new safety concerns identified. The treatment’s safety profile was consistent with prior trials of C5 inhibitors in gMG.
Full trial results are expected to be presented at an upcoming medical conference and submitted to regulatory authorities worldwide.