- Design
- Phase 3, double-blind, placebo-controlled randomised trial
- Population
- 260 adults with AChR antibody-positive generalised myasthenia gravis, 20 countries
- Primary outcome
- Change in MG-ADL score at week 26
- Effect
- −4.2 vs −2.6, difference −1.6 (95% CI −2.4 to −0.8); QMG difference −2.1 (−3.1 to −1.1)
PREVAIL randomised 260 adults with acetylcholine receptor antibody-positive generalised myasthenia gravis at 113 sites in 20 countries to weekly subcutaneous gefurulimab, a nanobody that blocks complement C5, or placebo for 26 weeks.
The MG-ADL score improved by 4.2 points with gefurulimab and 2.6 with placebo, a difference of 1.6. The QMG score improved by 2.1 points more. Improvement began within a week. Adverse events were similar, mainly injection-site reactions and headache, and no meningococcal infections occurred.
Complement inhibitors already used in myasthenia are given intravenously. A weekly self-injected option would change the logistics of care. Regulatory status is not established from this record, and availability and cost in India are unknown. As with other C5 inhibitors, meningococcal vaccination would be required.
- Note gefurulimab as a possible future self-injected complement inhibitor
- Remember complement inhibitors require meningococcal vaccination
- Keep established treatments for antibody-positive generalised myasthenia as the standard
- Check regulatory status before discussing access with patients
Why it matters
Complement inhibition in myasthenia could move from infusion clinics to weekly home injection.
Don't overread it
The average improvement over placebo is below the usual threshold for a clinically meaningful individual change, and follow-up was 26 weeks.
The statistics, in plain English
A treatment difference of −1.6 MG-ADL points (95% CI −2.4 to −0.8) is statistically clear. A 2-point change is usually considered clinically meaningful for an individual, so the average gain over placebo is modest, though some patients will benefit more.
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