Subcutaneous efgartigimod PH20 (Vyvgart Hytrulo) met its primary endpoint in the phase III ADAPT OCULUS trial, according to interim data presented at the American Association of Neuromuscular and Electrodiagnostic Medicine meeting in Orlando. Among 141 patients with ocular myasthenia gravis, those randomized to efgartigimod had a mean 4.04-point improvement from baseline in the Myasthenia Impairment Index patient-reported outcome (MGII PRO) ocular score at 4 weeks, compared with a 1.99-point improvement with placebo (mean difference 2.05, P=0.012).
On the key secondary endpoint combining MGII PRO with physician examination, efgartigimod produced a 5.02-point mean change versus 2.57 with placebo (P=0.018). The MG-ADL ocular domain score showed a similar numerical trend but did not reach statistical significance (P=0.60). Investigators said efgartigimod significantly improved diplopia and ptosis, and that the MGII PRO results support its use for detecting treatment effects in ocular myasthenia gravis.
Ocular myasthenia gravis has been historically understudied, and the trial is the first registrational study to evaluate a targeted therapy specifically for the condition. The study enrolled patients with any myasthenia gravis serotype, including anti-AChR antibody-positive and triple seronegative patients, and improvements were seen across treatment cycles in both populations. Adverse events were consistent with previous studies, with headache, injection site erythema, and upper respiratory tract infections most common. Efgartigimod is not yet FDA-approved for ocular myasthenia gravis.