OCS are used to treat patients with anti-acetylcholine receptor antibody-positive (AChR-Ab+) gMG. However, high-dose therapy and long-term use—even at lower doses—are associated with substantial systemic adverse effects (AEs). Ravulizumab, a complement component 5 inhibitor approved for AChR-Ab+ gMG, enables reduction and discontinuation of OCS, while maintaining symptom control. Treatment guidelines recommend steroid-sparing strategies, yet clinical practice trends employ prolonged OCS tapering regimens with higher steroid exposure and risk of associated AEs compared with faster tapering. OCTAGON is a global phase 4, prospective, multicenter, single-arm study investigating OCS tapering in adult patients with gMG receiving ravulizumab (NCT07221838).

Planned enrollment: ~75 adults with gMG, receiving ravulizumab Q8W and a stable OCS regimen equivalent to a daily average of ≥7.5mg/day for ≥4weeks. A tapering schedule based on baseline (BL) OCS dose will be assessed. Patients with BL OCS 7.5-10mg/day will reduce by 2.5mg/day Q4W to 2.5mg/day, then by 1.25mg/day Q4W until completion. Patients with BL OCS >10mg/day will reduce by 5mg/day Q2W to 10mg/day, then follow the schedule for those with BL OCS 7.5-10mg/day. Primary endpoint is the proportion of patients who discontinue OCS or reduce to ≤5mg/day (if the reason for no further OCS reduction is suspected adrenal insufficiency) and maintain for ≥4weeks without gMG clinical deterioration.

OCTAGON addresses a critical unmet need for an evidence-based rapid OCS tapering schedule in patients with gMG. Results will provide a framework for effective and safe OCS treatment management in the targeted immunotherapy era, minimizing risks associated with prolonged corticosteroid exposure, while optimizing outcomes for patients with gMG receiving ravulizumab.