Efficacy and safety of complement inhibitors and FcRn blockers in generalized AChR antibody-positive myasthenia gravis: a meta-analysis.

BACKGROUND

Antibody status is increasingly used to inform treatment strategies in generalized myasthenia gravis (gMG). We evaluated the efficacy and safety of complement inhibitors and neonatal Fc receptor (FcRn) blockers versus placebo or standard care in adults with acetylcholine receptor antibody-positive (AChR-Ab⁺) gMG.

METHODS

We systematically searched MEDLINE, EMBASE, Cochrane Central Register Controlled Trials, and ClinicalTrials.gov through November 2024. Eligible randomized controlled trials (RCTs) informed short-term analyses while long-term outcomes were extracted from open-label extension (OLE) studies. Pooled mean difference (MD) and odds ratio (OR) were calculated using random-effects model.

RESULTS

Six RCTs (n = 739) and four OLEs (n = 588) evaluating eculizumab, ravulizumab, zilucoplan, efgartigimod, rozanolixizumab, and batoclimab were included. Both drug classes significantly improved mean changes from baseline versus placebo in Myasthenia Gravis Activities of Daily Living [MD 1.7, 95% confidence interval (CI) 1.1-2.3], Quantitative Myasthenia Gravis [MD 2.7, 95%(CI)1.8-3.5], Myasthenia Gravis Composite [MD 6.3, 95%(CI) 5-7.6], MGQoL15r [MD 3.4, 95%(CI)1.2-5.6], and Neuro-QoL [MD 4.5, 95%(CI)1.2-7.7]. Odds of achieving clinically meaningful MG-ADL and QMG improvements were more than doubled (ORs 2.7 and 3.5). Risks of clinical worsening and rescue therapy use were reduced by 72% and 48%, respectively. Complement inhibitors OLEs showed durable benefit up to 156 weeks; 30% of patients reduced corticosteroid doses. Rates of serious adverse events, discontinuation, and mortality were comparable to placebo.

CONCLUSION

In AChR-Ab⁺ gMG, complement inhibitors and FcRn blockers yield clinically meaningful improvements with favourable safety profiles. Complement inhibition additionally confers sustained benefits and corticosteroid-sparing effects in this population over long-term.

PROTOCOL REGISTRATION: PROSPERO ID: CRD42024513406.