AstraZeneca Achieves Phase III Milestone with Nanobody Therapy for Myasthenia Gravis
SHERIDAN, WYOMING – July 25, 2025 – AstraZeneca has reported positive topline results from its Phase III PREVAIL trial evaluating gefurulimab, a complement C5-inhibiting nanobody, for the treatment of generalized myasthenia gravis (gMG). The investigational therapy met all primary and secondary endpoints, signaling a potential new contender in the highly competitive $20 billion gMG market.
Phase III Results Suggest Clinical Significance
According to AstraZeneca’s announcement, gefurulimab demonstrated “a statistically significant and clinically meaningful improvement from baseline” based on the Myasthenia Gravis Activities of Daily Living (MG-ADL) scale. Although specific trial data have not yet been published, the company confirmed that the results apply to patients with anti-acetylcholine receptor (AChR) antibody-positive gMG—representing approximately 85% of all gMG cases.