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Nipocalimab the first and only FcRn blocker approved in anti-acetylcholine receptor– or anti-muscle-specific kinase adults and children with generalized myasthenia gravis.
The FDA approved nipocalimab-aahu (Imaavy; Johnson & Johnson) for the treatment of patients with generalized myasthenia gravis (gMG). The approval, according to a news release, follows a priority review indicating nipocalimab to treat adults and children aged 12 years and older with gMG who are anti-acetylcholine receptor (AChR) or anti-muscle-specific kinase (MuSK) antibody–positive.1
Image credit: Luciano Luppa | stock.adobe.com
Nipocalimab is a monoclonal antibody designed to bind with high affinity to block FcRn and reduce the levels of circulating immunoglobulin G (IgG) antibodies that underlie gMG without any additional detectable effects on other adaptive and essential immune functions. Nipocalimab’s biologics license application was granted a priority review by the FDA in January 2025, and prior to this action, it received a fast track designation in December 2021 and an orphan drug designation in February 2021.1-3
MG is an autoantibody disease in which the immune system mistakenly makes antibodies that target proteins at the neuromuscular junction and can block or disrupt normal signaling from nerves to muscles, therefore impairing or preventing muscle contraction. gMG is specifically characterized by severe muscle weakness of the skeletal muscles and difficulties in speech and swallowing.2,3 Patients who are anti-AChR and anti-MuSK antibody–positive comprise at least 90% of the total antibody-positive gMG population.1 Vulnerable populations, such as pediatric patients, have more limited therapeutic options, with current standard-of-care (SOC) treatments being generalized from adult trials.2,3
Vivacity-MG3
Vibrance-MG
“We consistently hear from individuals living with MG who are hopeful for new treatment options that may help bring greater stability, independence, and predictability to their lives,” Samantha Masterson, president and CEO, Myasthenia Gravis Foundation of America, said in a news release. “Today’s announcement provides another option which could help address the constant uncertainty and heavy physical and mental toll that MG symptom relapse presents to patients and their families.”1
The approval is supported by data from the ongoing pivotal study, Vivacity-MG3 (NCT04951622)4, a multicenter, randomized, double-blind, placebo-controlled phase 3 trial evaluating the efficacy, safety, pharmacokinetics, and pharmacodynamics of nipocalimab when administered in adults with gMG. In this trial, nipocalimab in combination with SOC demonstrated superior disease control throughout a 24-week duration when compared with placebo and SOC (measured by the Myasthenia Gravis Activities of Daily Living [MG-ADL] scale).1,4
Additionally, many of these patients had maintained improvements up to 20 months of follow-up in the ongoing open-label extension of the study. Nipocalimab also demonstrated a rapid and sustained reduction in autoantibody levels by up to 75% from the first dose and throughout a 24-week monitoring period.1,4
“The clinical results we’ve seen with [nipocalimab] represent a significant milestone in the treatment of gMG. 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 the news release. “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.”1
Further, nipocalimab and SOC also met its primary end point in the pediatric phase 2/3 Vibrance-MG trial (NCT05265273)5, with an approximate 69% reduction in total serum IgG over 24 weeks in patients aged 2 to less than 18 years. Secondary end points of improvements in MG-ADL and Quantitative Myasthenia Gravis scores. The experts reported that nipocalimab had comparable tolerability in both adult and pediatric populations, with a consistent safety profile across both the Vivacity-MG3 and Vibrance-MG studies.1,4,5
“Today’s FDA approval of [nipocalimab] marks a historic milestone for the more than 240 million patients suffering with autoantibody diseases, many with few or no approved targeted treatments,” David Lee, MD, PhD, global immunology therapeutic area head, Johnson & Johnson innovative medicine, said in the news release. “This approval is the result of years of scientific commitment, collaboration, and determination for our nipocalimab program, and we’re proud to bring this new treatment option to patients living with anti-AChR or anti-MuSK antibody–positive gMG.”1
