To report the design of a Phase 3, randomized, double-blind, placebo-controlled study evaluating the efficacy and safety of subcutaneous (SC) efgartigimod PH20 (coformulated with recombinant human hyaluronidase PH20), an immunoglobulin G (IgG)1 antibody Fc-fragment that selectively reduces IgG levels by blocking neonatal Fc receptor (FcRn)-mediated IgG recycling, in ocular myasthenia gravis (oMG).

An unmet need exists for approved, effective treatments for patients with oMG. Retrospective analysis of data supporting the approval of efgartigimod for treatment of adults with generalized myasthenia gravis (gMG) indicated an improvement in ocular symptoms in this population. The Phase 3 ADAPT OCULUS Trial (NCT06558279) will investigate the efficacy and safety of efgartigimod in participants with oMG.

Adults with confirmed oMG and a Myasthenia Gravis Impairment Index (MGII) patient-reported outcome (PRO) subcomponent ocular score ≥6 who are on stable MG therapy will be randomized 1:1 to receive 4 once-weekly efgartigimod PH20 SC 1000 mg or placebo injections administered via prefilled syringe (PFS), followed by 4 weeks of follow-up. Participants may continue in the up-to-2-year open-label extension part of the study evaluating long-term efgartigimod PH20 SC efficacy and safety in oMG.

The primary endpoint is change in MGII PRO ocular score from baseline to Week 4. Key secondary endpoints include changes from baseline to Week 4 in MGII ocular score (PRO plus physical examination), Myasthenia Gravis Activities of Daily Living ocular domain score, and MGII total score. Statistical analyses for efficacy endpoints will be conducted in hierarchical order at a 1-sided significance level of α=.025. Safety assessments include adverse event incidence and severity.

This is the first Phase 3 clinical trial evaluating the safety and efficacy of efgartigimod PH20 SC in patients with oMG that addresses the unmet need for treatment in oMG.