Neuromuscular · Clinical trials
Myasthenia Gravis Clinical Trials
Approved therapies, the pivotal-trial endpoints they were judged on, the magnitude of benefit — and the drugs that failed their endpoints, and why.
Indication overview
About myasthenia gravis — and why its trials are hard
Myasthenia gravis (MG) is an autoantibody-mediated disorder of the neuromuscular junction causing fatigable weakness of ocular, bulbar, limb, and respiratory muscles. Most patients have antibodies against the acetylcholine receptor (AChR); smaller subsets have anti-MuSK or anti-LRP4 antibodies. Foundational therapy combines the acetylcholinesterase inhibitor pyridostigmine for symptom relief with corticosteroids and steroid-sparing immunosuppressants; thymectomy benefits many AChR-positive patients, and IVIG or plasma exchange treat crises. The last decade brought a wave of targeted biologics. Complement C5 inhibitors eculizumab (REGAIN) and ravulizumab (CHAMPION-MG), plus the C5 inhibitor zilucoplan (RAISE, 2023), block terminal complement-mediated damage at the endplate in AChR-positive gMG. Neonatal Fc receptor (FcRn) antagonists efgartigimod (ADAPT) and rozanolixizumab (MycarinG, 2023) lower pathogenic IgG. These agents deliver rapid, meaningful improvements in MG-ADL and QMG scores, transforming refractory generalized MG management.
Approved therapies & pivotal evidence
What's been approved — and by how much it moved the endpoint
| Drug (brand) | Approved | Setting | Pivotal trial | Primary endpoint | Magnitude of benefit |
|---|---|---|---|---|---|
| Pyridostigmine (Mestinon) | 1955 | Symptomatic first-line, all subtypes | Established by long clinical use (pre-modern RCT era) | Symptomatic strength/fatigability improvement | Rapid symptomatic relief; not disease-modifying |
| Corticosteroids / immunosuppressants (e.g., prednisone, azathioprine) ((generic)) | long-established | First-line immunotherapy / steroid-sparing | Multiple trials (e.g., azathioprine + prednisolone) | Remission/minimal manifestation status; steroid sparing | Backbone chronic immunotherapy |
| Eculizumab (Soliris) | 2017 | Refractory AChR+ generalized MG | REGAIN (Phase 3) | Change in MG-ADL (worst-rank ANCOVA) | Primary endpoint not met by prespecified worst-rank test, but consistent benefit across sensitivity analyses and secondary endpoints (QMG) supported approval |
| Ravulizumab (Ultomiris) | 2022 | AChR+ generalized MG | CHAMPION-MG (Phase 3) | Change in MG-ADL at week 26 | MG-ADL improved ~-3.1 vs ~-1.4 placebo; long-acting C5 inhibitor dosed every 8 weeks |
| Efgartigimod alfa (Vyvgart) | 2021 | AChR+ generalized MG (SC form Vyvgart Hytrulo later added) | ADAPT (Phase 3) | Proportion of MG-ADL responders (AChR+) | 68% MG-ADL responders vs 30% placebo; FcRn antagonist reduces IgG |
| Rozanolixizumab (Rystiggo) | 2023 | AChR+ or MuSK+ generalized MG | MycarinG (Phase 3) | Change in MG-ADL at day 43 | MG-ADL LS-mean change ~-3.4 vs ~-0.8 placebo; FcRn antagonist covering both AChR+ and MuSK+ |
| Zilucoplan (Zilbrysq) | 2023 | AChR+ generalized MG | RAISE (Phase 3) | Change in MG-ADL at week 12 | MG-ADL LS-mean difference ~-2.1 vs placebo; self-administered daily SC C5 inhibitor |
Where trials have failed
Drugs that missed their endpoint — and what contributed
The most instructive lessons in myasthenia gravis development come from programmes that failed the endpoint that mattered.
| Drug / trial | Endpoint outcome | What contributed |
|---|---|---|
| Belimumab — BEL115123 (Phase 2) | Did not meet primary endpoint | The anti-BLyS/BAFF antibody failed to significantly improve QMG versus placebo in generalized MG. |
| Rituximab (AChR+ gMG) — BeatMG (Phase 2) | Did not meet its primary steroid-sparing endpoint in AChR+ gMG | Benefit seen anecdotally and in MuSK+ disease was not confirmed in the AChR+ randomized trial, though it remains used off-label in refractory/MuSK cases. |
Choosing the right endpoint
Primary endpoints that matter in myasthenia gravis trials
- MG-ADL — Patient-reported 8-item activities-of-daily-living scale; the primary endpoint for most modern complement and FcRn trials.
- QMG (Quantitative MG score) — Physician-administered 13-item quantitative strength/fatigability score; common key secondary endpoint.
- MGC (MG Composite) — Combines physician and patient assessments across muscle domains.
- MG-QoL15r — Disease-specific quality-of-life instrument capturing patient impact.
- Minimal manifestation / steroid sparing — Reaching minimal-manifestation status and reducing corticosteroid dose are clinically meaningful chronic-management goals.
How iNGENū runs myasthenia gravis trials
Physician-led design, built for FDA submission
Endpoint & biomarker strategy
Board-certified specialists design endpoints and patient selection aligned to current FDA guidance for this indication.
FDA-ready data
Built to ICH-GCP and 21 CFR 312.120, with direct FDA submission — data accepted by the FDA, EMA and MHRA.
Faster, lower-cost delivery
~4-week ethics via the TGA CTN scheme, up to 43.5% R&D rebate, and 80–90% below US CRO cost.
Request a fixed-milestone proposal and a tailored endpoint & feasibility summary for this indication.
Frequently asked questions
Myasthenia Gravis clinical trials — FAQs
How do FcRn antagonists differ from complement inhibitors in MG?
Is pyridostigmine a cure?
What treats a myasthenic crisis?
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