Weekly self-injection improves generalized myasthenia gravis symptoms

Clinical takeaway: For adults with AChR antibody–positive generalized myasthenia gravis, once-weekly subcutaneous gefurulimab produced clinically meaningful improvements within weeks. Longer-term data are still needed to establish durability and safety beyond 6 months.

Although several targeted therapies are available for AChR antibody-positive generalized myasthenia gravis, many require IV administration, repeated infusion visits, or daily dosing. Gefurulimab may help address an important unmet need by delivering complement inhibition through a convenient once-weekly subcutaneous self-injection.

In the phase 3 PREVAIL trial, investigators randomized 260 adults with AChR antibody–positive generalized myasthenia gravis to self-administer gefurulimab or placebo once weekly for 26 weeks. Most participants continued stable background therapy, and 96% completed the randomized treatment period.

Daily functioning improved as early as week 1. At week 26, Myasthenia Gravis Activities of Daily Living scores decreased by 4.2 points with gefurulimab versus 2.6 points with placebo. Nearly two-thirds of gefurulimab-treated patients achieved at least a 3-point improvement, compared with about half of placebo recipients.

Objective muscle-strength findings followed a similar pattern. Quantitative Myasthenia Gravis scores improved by 4.5 points with gefurulimab versus 2.4 points with placebo. A clinically substantial improvement of at least 5 points occurred in 46.8% and 28.0% of patients, respectively. Rescue therapy was required by 5.3% of gefurulimab recipients versus 12.4% of placebo recipients.

Adverse events occurred in 75.6% of the gefurulimab group and 80.6% of the placebo group and were predominantly mild or moderate. Injection-site reactions were more frequent with gefurulimab (9.9% versus 3.1%) but declined over time and caused no discontinuations. No meningococcal infections were reported.

The authors said the results support gefurulimab as an “effective and convenient option,” while noting that the ongoing open-label extension will be needed to assess long-term outcomes. The trial was funded by Alexion, AstraZeneca Rare Disease.

Source: Gwathmey KG, et al. (2026 July 22) JAMA Neurol. Efficacy and Safety of Gefurulimab in Generalized Myasthenia Gravis: The PREVAIL Phase 3 Randomized Clinical Trial