Nipocalimab Phase 3 trial shows longest disease control in broadest myasthenia gravis population

Johnson & Johnson announced positive outcomes from the Phase 3 Vivacity-MG3 study of nipocalimab in patients with generalized myasthenia gravis (gMG). The study demonstrated that nipocalimab combined with standard of care (SOC) was superior to a placebo combined with SOC, achieving the primary endpoint of an improvement in the MG-ADL score over 24 weeks. These findings will be presented at the European Academy of Neurology (EAN) 2024 Congress and submitted to regulatory authorities later this year.

Katie Abouzahr, M.D., emphasized the necessity for new treatment options for gMG, a chronic, autoantibody-driven disease. Carlo Antozzi, M.D., from the Neurological Institute Foundation C. Besta in Milan, noted the sustained response of nipocalimab over six months, highlighting its potential to address chronic and unpredictable exacerbations in myasthenia gravis.

The double-blind, placebo-controlled study included a broad population of anti-AChR+, anti-MuSK+, and/or anti-LRP4+ patients, representing about 95% of the gMG population. Patients on nipocalimab plus SOC improved by 4.70 points on the MG-ADL scale, significantly more than the 3.25-point improvement observed with placebo plus SOC. A 1- to 2-point change in MG-ADL can significantly affect a patient's quality of life, such as normal eating versus frequent choking or breathing comfortably versus requiring ventilation.

In addition to meeting the primary endpoint, nipocalimab also met critical secondary endpoints. Improvement in muscle strength and function, measured by QMG, was significantly greater with nipocalimab plus SOC compared to placebo plus SOC. Additionally, MG-ADL response (≥2-point improvement from baseline) was significantly greater for nipocalimab plus SOC over the 24-week period. Safety and tolerability of nipocalimab were consistent with other studies, with similar incidence rates of adverse events compared to the placebo group.

Dr. Abouzahr expressed excitement over the new data presented at the EAN 2024 Annual Meeting, which underscores Johnson & Johnson's commitment to advancing treatment for autoantibody-driven diseases.

Generalized myasthenia gravis (gMG) is an autoimmune condition where autoantibodies target proteins at the neuromuscular junction, disrupting muscle contraction. It affects approximately 700,000 people worldwide. Initial symptoms are usually ocular, but over half of the patients progress to generalized MG, which involves fluctuating weakness of skeletal muscles and symptoms like limb weakness, drooping eyelids, double vision, and difficulties with chewing, swallowing, speech, and breathing. Current SOC therapies manage gMG, but new treatments are needed for those who do not respond adequately.

The Vivacity-MG3 study was designed to measure sustained efficacy and safety with consistent dosing in this unpredictable chronic condition. Adult gMG patients who had an insufficient response to ongoing SOC therapy were enrolled in the 24-week double-blind trial. The primary endpoint was the mean change in MG-ADL score from baseline, and a key secondary endpoint was the change in QMG score. Long-term safety and efficacy are being assessed in an ongoing open-label extension phase.

Nipocalimab is an investigational monoclonal antibody designed to block FcRn and reduce levels of circulating IgG antibodies while preserving immune function. This mechanism aims to address various conditions in the autoantibody space, including rare autoantibody diseases, maternal-fetal diseases, and prevalent rheumatology conditions. The FDA and EMA have granted several key designations to nipocalimab, including Fast Track and Orphan Drug status for various conditions, underscoring its potential clinical impact.