FDA Approves Nipocalimab for Generalized Myasthenia Gravis

The FDA Wednesday approved nipocalimab-aahu (Imaavy; Johnson & Johnson) for the treatment of generalized myasthenia gravis (gMG) in adults and pediatric patients 12 years or older who are anti–acetylcholine receptor positive (AChR+) or anti–muscle-specific kinase antibody positive (MuSK+).¹ The approval of the FcRn-blocking monoclonal antibody, which works by reducing immunoglobulin G (IgG), was supported by data from the ongoing Vivacity-MG3 study.

Nipocalimab joins a roster of several other currently approved FcRn receptor blockers—rozanolixizumab-noli (Rystiggo; UCB), efgartigimod alfa-fcab (Vyvgart; Argenx), and efgartigimod alfa and hyaluronidase-qvfc (Vyvgart Hytrulo; Argenx)—along with other options such as acetylcholinesterase inhibitors, complement inhibitors, and corticosteroids to treat MG.² The chronic autoimmune disorder affects the signals at the neuromuscular junction, causing muscle weakness and fatigue.

The release announcing nipocalimab’s approval touts its long-lasting benefits, demonstrated over the course of the ongoing phase 3 Vivacity-MG3 study (NCT04951622), which is assessing the agent’s efficacy and safety among adult patients with gMG who did not respond to standard of care (SOC).¹ A total of 153 antibody-positive patients were randomly assigned to receive either nipocalimab plus SOC (n = 77) or placebo plus SOC (n = 76). Change from baseline to weeks 22 to 24 in the Myasthenia Gravis-Activities of Daily Living (MG-ADL) score, which assesses patient-reported symptoms impacting their daily life, served as the primary efficacy end point.

Results published in February showed that the nipocalimab cohort experienced a larger reduction in MG-ADL total score, with a least-squares mean (SE) change of –4.70 (0.329) vs –3.25 (0.335) in the placebo group.³ According to the news release announcing the FDA approval, this improvement “translates into patients regaining essential daily functions, such as chewing, swallowing, speaking and breathing.”¹ The nipocalimab group also saw significant improvement in a key secondary end point, the change from baseline in Quantitative Myasthenia Gravis score, at –4.86 (0.504) compared with –2.05 (0.499).³

The data from Vivacity-MG3 point to the drug’s mechanism, with treated patients showing rapidly decreasing IgG levels starting at week 2. Its safety profile was also favorable, as most adverse events (AEs) were mild or moderate, with no significant differences seen between the treatment and control groups in infusion-related reactions, infections, and severe infections or infections. Serious AEs and discontinuations were less common in the nipocalimab group than the placebo group.

“Patients experienced substantial symptom relief and lasting disease control that translated into better daily function and did not fade over 24 weeks in the pivotal Vivacity-MG3 study,” Nicholas J. Silvestri, MD, professor of neurology at the University of Buffalo, said in Johnson & Johnson’s release.¹ “Having a treatment that delivers this level of durable symptom stability is a meaningful step forward for managing a complex and unpredictable disease like gMG, and to have it in both AChR+ and MuSK+ adults and pediatric patients 12 years and older brings an additional FcRn treatment to a broader range of patients.”

The open-label extension phase of Vivacity-MG3 is ongoing, which will show longer-term safety and efficacy of nipocalimab in participants with gMG. Interim results presented at the recent American Academy of Neurology meeting showed sustained disease control over 72 weeks with nipocalimab.⁴

References

1. Johnson & Johnson receives FDA approval for IMAAVYTM (nipocalimab-aahu), a new FcRn blocker offering long-lasting disease control in the broadest population of people living with generalized myasthenia gravis (gMG). News release. Johnson & Johnson. April 30, 2025. Accessed April 30, 2025. https://www.jnj.com/media-center/press-releases/johnson-johnson-receives-fda-approval-for-imaavytm-nipocalimab-aahu-a-new-fcrn-blocker-offering-long-lasting-disease-control-in-the-broadest-population-of-people-living-with-generalized-myasthenia-gravis-gmg

2. Myasthenia gravis treatments. Myasthenia Gravis Foundation of America. Accessed April 30, 2025. https://myasthenia.org/myasthenia-gravis-treatments/

3. Shaw ML. Phase 3 data support nipocalimab for myasthenia gravis. AJMC^®. February 7, 2025. Accessed April 30, 2025. https://www.ajmc.com/view/phase-3-data-support-nipocalimab-for-myasthenia-gravis

4. Antozzi C, Vu T, Ramchandren S, et al. Long-term safety and efficacy of nipocalimab in generalized myasthenia gravis: Vivacity-MG3 open-label extension phase results. Neurology. 2025;104(7 suppl 1):P7-11.022. doi:10.1212/WNL.0000000000211115