Johnson & Johnson (JNJ) announced that the U.S. Food and Drug Administration (FDA) has approved IMAAVY (nipocalimab-aahu), a novel human monoclonal antibody that blocks the neonatal Fc receptor (FcRn), for the treatment of generalized myasthenia gravis (gMG). This approval, granted under FDA Priority Review, offers a new therapeutic option with the potential for lasting disease control in a wide range of gMG patients, including adults and pediatric individuals aged 12 and older who are positive for either anti-acetylcholine receptor (AChR) or anti-muscle-specific kinase (MuSK) antibodies.
Generalized myasthenia gravis is a chronic autoimmune disease characterized by muscle weakness. The approval of IMAAVY addresses a significant unmet need for effective and safe therapies that can provide sustained disease control for patients. Anti-AChR and anti-MuSK antibody-positive individuals represent the vast majority (≥90%) of the antibody-positive gMG population. IMAAVY works by selectively reducing immunoglobulin G (IgG), including the harmful autoantibodies that drive gMG, without broadly impacting other immune functions.
The FDA’s decision was supported by compelling data from the pivotal Vivacity-MG study, the longest primary endpoint registrational trial for any FcRn blocker in adults with gMG. The study demonstrated that IMAAVY, when added to standard of care, provided superior disease control over 24 weeks compared to placebo plus standard of care, as measured by significant improvements in the Myasthenia Gravis-Activities of Daily Living (MG-ADL) score. This translated to patients experiencing improvements in essential daily functions like chewing, swallowing, speaking, and breathing. Furthermore, participants treated with IMAAVY maintained these improvements for up to 20 months in the ongoing open-label extension study. The treatment also showed a rapid and sustained reduction in autoantibody levels, by as much as 75% from the first dose.
Dr. Nicholas J. Silvestri, Professor of Neurology at the University of Buffalo, hailed the clinical results as a “significant milestone” in gMG treatment. He noted the durable symptom relief and improved daily function observed in patients over the 24-week study period, emphasizing the benefit of having a treatment effective in both AChR+ and MuSK+ adults and pediatric patients.
Additionally, data from the ongoing Vibrance Phase 2/3 pediatric study in adolescents (12-17 years) with anti-AChR and anti-MuSK antibody-positive gMG showed that IMAAVY plus standard of care met its primary endpoint with a substantial 69% reduction in total serum IgG over 24 weeks, along with improvements in key secondary endpoints.
IMAAVY demonstrated a consistent and comparable safety profile across both adult and pediatric studies.
Samantha Masterson, President and CEO of the Myasthenia Gravis Foundation of America, expressed hope that this new treatment option will bring greater stability, independence, and predictability to the lives of individuals living with gMG.
David Lee, M.D., Ph.D., Global Immunology Therapeutic Area Head at Johnson & Johnson Innovative Medicine, highlighted the approval as a “historic milestone” for the millions suffering from autoantibody diseases. He underscored the years of scientific dedication that led to the development of nipocalimab.
Johnson & Johnson is committed to ensuring patient access to IMAAVY through a support program called IMAAVY withMe, which aims to provide eligible commercially insured patients with their first treatment quickly and potentially at a low out-of-pocket cost. Regulatory submissions for nipocalimab in gMG are currently under review by health authorities worldwide.