Open-Label Extension Highlights Continued Therapeutic Benefit of Nipocalimab in Patients Transitioning From Placebo

Results from the open-label extension (OLE) of the phase 3 Vivacity-MG3 trial indicated that patients with generalized myasthenia gravis (gMG) who transitioned from placebo to nipocalimab, an FcRn-blocking monoclonal antibody, along with standard-of-care treatment (SOC), exhibited improvements in MG-Activities of Daily Living (MG-ADL) and quantitative MG (QMG) scores as early as 2 weeks after the transition and continued improvement through the duration of the trial.¹

The analysis24-week, double-blind, phase 3 Vivacity-MG3 Study (NCT04951622) enrolled 98 patients with gMG to assess the efficacy of nipocalimab plus SOC treatment in those who transitioned from placebo plus SOC. Presented at the 2025 American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM) meeting, held October 29 to November 1, in San Francisco, California, results showed that those who switched from placebo to nipocalimab had statistically significant and clinically meaningful improvements in primary end points.

Led by Kristl Claeys, MD, PhD, head of the Laboratory for Muscle Diseases and Neuropathies in Belgium, patients on the treatments demonstrated a mean MG-ADL change of –1.33 ([SD, 2.13], n=87, P <0.001) that improved to –2.68 ([SD, 3.26], n=59, P <0.001) at OLE week 24. In the final week, 63.3% of patients achieved Meaningful Clinical Improvement (MCI), while 79.5% of patients achieved it at any time during OLE, and 51.1% of patients had sustained MCI. Similarly, QMG improvement was observed as early as week 4, with mean reported changes of –2.65 ([3.95], n=79, P =0.0010) that continued to –3.24([SD, 4.95], n=58, P <0.001) at week 24.

These within group mean changes were examined using pared t-test. Percentage of patients achieving MCI (2-point within-patient improvement versus baseline in MG-ADL) and sustained MCI (for 8W), and percentage-of-time spent in MCI were summarized. Data were collected for 24 consecutive weeks with the cutoff date August 23, 2024.

Read More: CHMP Issues Favorable Opinion for FcRn Blocker Nipocalimab as Myasthenia Gravis Treatment

These findings, paired with the original Vivacity-MG3 data, led to the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) recent decision to issue a positive recommendation for the approval of nipocalimab as an add-on to standard therapy gMG.²

If approved, nipocalimab would become the first FcRn blocker for both adult and adolescent gMG populations who are anti-acetylcholine (AChR) or anti-muscle specific kinase (MuSK) antibody-positive. The therapy, which gained FDA approval in April, is supported by data from the aforementioned phase 3 Vivacity-MG3 study, as well as supplemental findings from the phase 2/3 Vibrance-MG study (NCT05265273).

The Vivacity-MG3 trial, prior to the OLE, is the most notable trial in nipocalimab’s program. Comprised of 199 adult patients with antibody positive or negative gMG who had insufficient response to ongoing SOC therapy, were randomly assigned to nipocalimab plus current SOC. In the original trial data, patients treated with nipocalimab demonstrated a 4.70-point improvement in MG-ADL, the primary end point, over a 24-week period compared with improvements of 3.25 points for the placebo plus SOC group (P = .002).

Referances
1. Claeys K, Ait-thyaty M, Gandhi K, et al. Efficacy of Nipocalimab in Open-Label Extension in Patients Transitioned from Placebo: Results from Vivacity-MG3 Trial. Presented at the 2025 American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM) Annual Meeting, held October 29-November 1, in San Francisco, California. Abstract S24
2. 1. Johnson & Johnson receives positive CHMP opinion of nipocalimab to treat a broad population of antibody-positive patients living with generalised myasthenia gravis (gMG). News release. Johnson & Johnson. September 19, 2025. Accessed October 1, 2025. https://www.globenewswire.com/news-release/2025/09/19/3153183/0/en/Johnson-Johnson-receives-positive-CHMP-opinion-of-nipocalimab-to-treat-a-broad-population-of-antibody-positive-patients-living-with-generalised-myasthenia-gravis-gMG.html