Comparative Effectiveness and Safety of Emerging Myasthenia Gravis Therapies: Insights From a Bayesian Network Meta-Analysis

Highlight

This comprehensive Bayesian network meta-analysis compares the efficacy and safety of emerging treatments for generalized myasthenia gravis (MG), including FcRn inhibitors, C5 complement inhibitors (C5i), and CD19+ B-cell depletion therapy (BCDT).

The study found comparable improvements across therapies in muscle strength and activities of daily living scores, but FcRn inhibitors were associated with a higher incidence of treatment-related adverse events compared to placebo.

This work underscores the challenges of interpreting cross-trial differences due to population heterogeneity and emphasizes the need for prospective head-to-head clinical trials to guide personalized MG treatment.

Study Background

Myasthenia gravis (MG) is a chronic autoimmune neuromuscular disorder characterized by fluctuating muscle weakness and fatigue primarily caused by pathogenic autoantibodies targeting the neuromuscular junction. Generalized MG can significantly impair physical function and quality of life. Despite substantial progress in immunotherapies, treatment remains challenging due to variable patient responses and adverse event profiles.

Over the past decade, several novel biologic agents targeting specific immune pathways have emerged, including inhibitors of the neonatal Fc receptor (FcRn), complement component C5, and CD19+ B cells. These agents aim to reduce pathogenic IgG antibody levels or modulate immune cell activity, providing more targeted approaches than conventional broad immunosuppression. However, direct head-to-head prospective randomized clinical trials comparing these therapies are lacking, making optimal treatment selection difficult.

Study Design

The authors performed a Bayesian network meta-analysis registered with PROSPERO (ID: CRD42023428733) to synthesize evidence from randomized placebo-controlled trials in adults with generalized MG. A systematic search was conducted in five major databases (Scopus, Embase, Web of Science, CENTRAL, and MEDLINE) up to May 2, 2025.

Inclusion criteria required multiarm trials reporting mean change from baseline in either Quantitative Myasthenia Gravis (QMG) scores or Myasthenia Gravis-Activities of Daily Living (MG-ADL) scores, with uncertainty measures available. These are validated scales assessing muscle strength and functional ability, respectively.

The analysis incorporated 27 randomized controlled trials including 1,086 placebo and 1,232 treatment participants. Interventions assessed targeted B cells (CD19+ BCDT), FcRn, complement component C5 (C5i), CD40, interleukin-6 signaling, as well as standard immunoglobulin G reduction and broad immunosuppression treatments.

Key Findings

The network meta-analysis demonstrated substantial reductions in QMG scores compared with placebo-standard of care for the following treatments:

• FcRn inhibitors (mean difference -3.63 points; 95% credible interval: -4.43 to -2.77)
• C5 complement inhibitors (C5i) (-2.59 points; -3.92 to -1.28)
• CD19+ B-cell depletion therapy (BCDT) (-2.50 points; -5.11 to 0.12)

Similarly, improvements in MG-ADL scores were noted:

• FcRn inhibitors (-1.93 points; -2.21 to -1.65)
• C5i (-1.84 points; -2.48 to -1.19)
• CD19+ BCDT (-1.91 points; -2.97 to -0.84)

Comparative efficacy differences between the three classes were not statistically meaningful, indicating broadly comparable effectiveness.

Regarding safety, FcRn inhibitors were associated with significantly increased odds of treatment-related adverse events (odds ratio 2.20; 95% CI 1.52–3.38) relative to placebo. In contrast, C5i and CD19+ BCDT showed adverse event odds similar to placebo, suggesting more favorable safety profiles.

Sensitivity analyses revealed potential effect modification by demographic factors such as age and sex, indicating that differences in trial population characteristics may confound treatment effect estimation across studies.

Expert Commentary

This meta-analysis provides valuable indirect comparison evidence supporting the therapeutic equivalence of FcRn, complement C5, and CD19+ B-cell targeted therapies for generalized MG, contributing to data-driven treatment decisions in the absence of head-to-head trials.

FcRn inhibitors mechanistically reduce pathogenic IgG by blocking IgG recycling, while complement C5 inhibitors disrupt complement-mediated neuromuscular junction damage, and B-cell depletion therapies reduce antibody-producing cells. The comparable clinical benefits observed align with their complementary but distinct immunomodulatory mechanisms.

However, the increased adverse event risk observed with FcRn inhibitors warrants cautious clinical use, underscoring the importance of individualized risk-benefit assessment. Moreover, the potential confounding effects of patient demographics highlight the need for trials with more consistent population characteristics or adjusted analytic approaches.

Limitations include inherent heterogeneity in study design, patient selection, outcome definitions, and the indirectness of network meta-analytic comparisons. The non-significant point estimate confidence interval for CD19+ BCDT in QMG improvement (-5.11 to 0.12) suggests variability requiring further confirmation.

Current international MG guidelines recommend these newer agents primarily for refractory or inadequate response cases. This analysis supports expanding consideration for these targeted therapies earlier in the disease course, balanced against safety profiles and patient preferences.

Conclusion

In conclusion, FcRn inhibitors, C5 complement inhibitors, and CD19+ B-cell depletion therapies demonstrate comparable efficacy in improving muscle strength and daily functioning in generalized myasthenia gravis patients, with FcRn inhibitors carrying a greater risk of treatment-related adverse events.

This comprehensive Bayesian network meta-analysis highlights the complexities in comparing MG therapies across heterogeneous trial populations and emphasizes the urgent need for prospective, well-powered head-to-head randomized controlled trials to establish definitive comparative effectiveness and safety profiles.

Personalized therapy selection in MG should integrate clinical characteristics, treatment response patterns, and safety considerations until more direct evidence is available.

Funding and Trial Registration

The study was registered on PROSPERO (ID: CRD42023428733). Funding sources were not specified in the provided abstract.

References

McLaren NP, Rosati M, Zhong W, Hussain S, Funaro MC, Nowak RJ, Roy B. Comparison of the Efficacy and Safety of Myasthenia Gravis Treatments: A Bayesian Network Meta-Analysis. Neurology. 2026 Jul 17;107(3):e218351. PMID: 42467874.

Additional relevant literature can be found in international guidelines on MG management, and recent clinical trials on FcRn inhibitors, complement C5 inhibitors, and anti-CD19 B-cell agents.