Efgartigimod Meets Primary End Point in Phase 3 ADAPT OCULUS Study of Ocular Myasthenia Gravis

Newly announced topline results from a phase 3 study dubbed ADAPT OCULUS (NCT06558279) showed that efgartigimod (Vyvgart; argenx) met its primary end point, demonstrating significant clinical improvements in adults with ocular myasthenia gravis (oMG). Based on these findings, argenx is expected to submit a biologics license application to expand efgartigimod’s label into oMG.¹

ADAPT OCULUS, a phase 3, double-blind, placebo-controlled, parallel-group, registrational trial, featured 141 patients with oMG, using change in Myasthenia Gravis Impairment Index (MGII) ocular score at week 4 as the primary end point. After 4 weeks of treatment, patients on the approved medication demonstrated statistically significant improvement on this primary end point, with P values of 0.012 relative to placebo. Additional data from the study is expected to be presented at an upcoming meeting.

In Part A of the study, participants were randomized 1:1 to receive four once-weekly subcutaneous injections of efgartigimod PH20 or placebo, followed by a 4-week follow-up period. In Part B, the open-label extension, participants received two cycles of four once-weekly efgartigimod injections separated by a 4-week interval, with additional cycles permitted from Cycle 3 onward at least one week after the prior cycle based on clinical status.

Additional data from the release showed that efgartigimod-treated patients had a 4.04-point mean improvement in MGII patient-reported outcome (PRO) whereas those on placebo showed changes of 1.99. Notably, those treated with the approved therapy also had marked reductions in key ocular symptoms, such as diplopia and ptosis.

“Ocular myasthenia gravis significantly impacts patients’ daily lives, affecting vision, independence and the ability to do routine tasks, such as work or drive a car. Yet today, there are no approved targeted medicines for this disease,” Carolina Barnett-Tapia, MD, PhD, associate professor of medicine at the University of Toronto, said in a statement.¹ “The improvements observed with VYVGART in the OCULUS trial offer hope to the thousands of myasthenia gravis patients with ocular involvement.”

For ADAPT OCULUS, Adults aged 18 years or older with confirmed myasthenia gravis were eligible if they were AChR antibody–positive or had abnormal neuromuscular transmission with documented treatment response. Participants were required to have MGFA Class I ocular disease and an MGII ocular score of at least 6 at screening and baseline. Of note, those with other causes of ptosis, diplopia, or muscle weakness, or medical conditions that could confound assessment or increase risk, were excluded.

Efgartigimod Approval History

A first-in-class neonatal Fc receptor antagonist, efgartigimod works by binding to FcRn and blocking IgG recycling, which accelerates the degradation of circulating IgG antibodies. The drug’s first regulatory approval came in December 2021, when the US approved an intravenous formulation for adults with generalized myasthenia gravis (gMG) who are anti-acetylcholine receptor antibody positive.²

In 2023, the FDA approved a subcutaneous formulation of the therapy, marketed as Vyvgart Hytrulo, as another option for adults with gMG. The decision was based on data from the phase 3 ADAPT-SC study (NCT04735432), which evaluated the noninferiority of the pharmacodynamic profile effect of SC efgartigimod as compared with the previously approved intravenous administration.³

About a year later, the drug gained another indication, this time for patients with chronic inflammatory demyelinating polyneuropathy (CIDP), another autoimmune condition. At the time, it became the first and only FcRn blocker approved for the treatment of CIDP, available as a once-weekly, 30- to 90-second subcutaneous injection.⁴

Argenx is currently seeking another indication for efgartigimod in patients with seronegative gMG, a group with no FDA-approved therapies available. The company has a supplemental biologics license application (sBLA) currently under review by the FDA, with a decision expected to come by May 10, 2026. Efgartigimod’s sBLA was based on data from the phase 3 ADAPT SERON study (NCT06298552), a randomized, double-blind, placebo-controlled trial that featured 119 patients followed over a 5-week treatment period.⁵

REFERENCES
1. argenx Announces Positive Topline Results from Phase 3 ADAPT OCULUS Trial of VYVGART in Ocular Myasthenia Gravis. News release. Argenx. February 26, 2026. Accessed February 26, 2026. https://argenx.com/news/2026/press-release-3245183.html
2. FDA Approves New Treatment for Myasthenia Gravis. News release. FDA. December 17, 2021. Accessed February 26, 2026. https://www.fda.gov/news-events/press-announcements/fda-approves-new-treatment-myasthenia-gravis
3. argenx Announces U.S. Food and Drug Administration Approval of VYVGART Hytrulo (efgartigimod alfa and hyaluronidase-qvfc) Injection for Subcutaneous Use in Generalized Myasthenia Gravis. News release. Argenx. June 20, 2023. Accessed February 26, 2026. https://www.globenewswire.com/news-release/2023/06/20/2691658/0/en/argenx-Announces-U-S-Food-and-Drug-Administration-Approval-of-VYVGART-Hytrulo-efgartigimod-alfa-and-hyaluronidase-qvfc-Injection-for-Subcutaneous-Use-in-Generalized-Myasthenia-Grav.html
4. argenx Announces FDA Approval of VYVGART Hytrulo for Chronic Inflammatory Demyelinating Polyneuropathy. News release. Argenx. June 21, 2024. Accessed February 26, 2026. https://www.us.argenx.com/news/argenx-announces-fda-approval-vyvgart-hytrulo-chronic-inflammatory-demyelinating-polyneuropathy
5. Argenx announces FDA acceptance of supplemental biologics license application with priority review for Vyvgart in AChR-Ab seronegative gMG. News release. Argenx. January 13, 2025. Accessed February 26, 2026. https://www.globenewswire.com/news-release/2026/01/13/3217457/0/en/argenx-Announces-FDA-Acceptance-of-Supplemental-Biologics-License-Application-with-Priority-Review-for-VYVGART-in-AChR-Ab-Seronegative-gMG.html