AstraZeneca's Gefurulimab Shows Promise in Treating Rare Autoimmune Disorder

AstraZeneca's experimental drug gefurulimab for generalized myasthenia gravis has shown significant and clinically meaningful reductions in disease severity and improved patients' ability to carry out daily tasks. The drug, which is a once-weekly self-administered injection, could generate $1.6 billion in revenue in 2031. Myasthenia gravis is a long-term autoimmune condition that affects the muscles that control the face and other parts of the body.

AstraZeneca's experimental drug gefurulimab has demonstrated significant and clinically meaningful reductions in disease severity and improved patients' ability to carry out daily tasks in a Phase III trial for generalized myasthenia gravis (gMG). The drug, a once-weekly self-administered injection, showed statistically significant and clinically meaningful improvement in functional activities of daily living (MG-ADL) total score at week 26 compared to placebo [1].

Gefurulimab, an investigational complement C5 inhibitor, is a dual-binding nanobody optimized for subcutaneous self-administration. It works by binding to the C5 protein in the terminal complement cascade, a part of the body's immune system, which over-responds and attacks healthy cells in an uncontrolled manner [1].

The PREVAIL Phase III trial, a global, randomized, double-blind, placebo-controlled study, enrolled 260 patients from 20 countries. Patients were randomized 1:1 to receive gefurulimab or placebo for a total of 26 weeks. The primary endpoint, change from baseline in the MG-ADL total score, was assessed at week 26 along with multiple secondary endpoints [1].

The trial results showed that gefurulimab met its primary and all secondary endpoints, demonstrating a statistically significant and clinically meaningful improvement in functional activities of daily living. This could potentially generate $1.6 billion in revenue by 2031, according to market analysts [2].

Myasthenia gravis is a rare, debilitating, chronic, autoimmune neuromuscular disease that leads to a loss of muscle function and severe weakness. Symptoms can include slurred speech, double vision, droopy eyelids, weakness, extreme fatigue, difficulty swallowing, choking, and respiratory failure [1].

Kelly Gwathmey, MD, Associate Professor of Neurology and principal investigator in the trial, commented, "Rapidly fluctuating symptoms and the unpredictable disability associated with gMG can affect nearly every aspect of a patient's life, making early intervention and sustained disease control a critical treatment goal. A once-weekly, self-administered C5 treatment option would offer patients greater convenience and independence in managing their condition, empowering them to have more control over their therapy."

Marc Dunoyer, Chief Executive Officer of Alexion, AstraZeneca Rare Disease, added, "Building on Alexion's pioneering leadership in gMG, 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. These data, reflecting patient participation across 20 countries, reinforce the established safety profile and efficacy of C5 inhibition and show the potential for gefurulimab as a first line biologic, with the convenience of a self-administered option."

Gefurulimab was well-tolerated, and the safety profile was consistent with previous trials of C5 inhibitors in gMG with no new safety signals observed. These data will be presented at a forthcoming medical meeting and shared with global regulatory authorities.

References:
[1] https://www.investegate.co.uk/announcement/rns/astrazeneca--azn/gefurulimab-nanobody-met-phase-iii-endpoints/8996456
[2] https://www.tradingview.com/news/reuters.com,2025-07-24:newsml_Wkr5TYw2S:0-gefurulimab-nanobody-met-phase-iii-endpoints/