FDA approves J&J’s nipocalimab, now Imaavy, to treat gMG
Therapy OK'd for patients ages 12 and older with AChR, MuSK antibodies
The U.S. Food and Drug Administration (FDA) has approved nipocalimab as a treatment for adults and adolescents, ages 12 and older, with generalized myasthenia gravis (gMG) who have antibodies against the acetylcholine receptor (AChR) or muscle-specific kinase (MuSK) proteins.
The newly approved therapy will be sold by developer Johnson & Johnson (J&J) under the brand name Imaavy.
This is the first regulatory approval for Imaavy in gMG. According to J&J, it’s now the only medication in the FcRn blocker class to be approved for both pediatric and adult populations with either antibody type.
“FDA approval of Imaavy marks a historic milestone,” David Lee, MD, PhD, global immunology therapeutic area head, J&J Innovative Medicine, said in a company press 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.”
Imaavy is also under regulatory review elsewhere, including in the European Union, for treating gMG.
Imaavy can be used for pediatric or adult gMG patients
Imaavy is given by a healthcare provider via intravenous, or into-the-vein, infusions every two weeks. The company is offering a patient support program in the U.S. called IMAAVY withMe, through which commercially insured patients who are prescribed the therapy may pay as little as $0 for each infusion, and may receive their first dose in as quickly as a week.
The new treatment option was met with enthusiasm from the myasthenia gravis (MG) community.
“We consistently hear from individuals living with myasthenia gravis who are hopeful for new treatment options that may help bring greater stability, independence and predictability to their lives,” said Samantha Masterson, president and CEO of the Myasthenia Gravis Foundation of America.
Masterson said the therapy’s approval “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.”
The symptoms of gMG, which include muscle weakness and fatigue, arise when self-reactive antibodies mistakenly attack proteins important for nerve-muscle communication. Approximately 85% of cases are caused by antibodies targeting AChR, with a smaller proportion — about 6% — driven by anti-MuSK antibodies.
Imaavy is an antibody therapy designed to block FcRn, or neonatal Fc receptor, a protein that normally prevents a class of circulating antibodies — including the ones that cause MG — from being broken down. By blocking FcRn, Imaavy intends to accelerate the rate at which these antibodies are destroyed, thereby lowering their levels to ease disease severity.
Other FcRn blockers are available on the U.S. market for gMG. However, Imaavy can be used for a broader group of patients, and is the only treatment approved for adolescents. Vyvgart and Vyvgart Hytrulo (both efgartigimod formulations) are approved for adults with anti-AChR antibodies, while Rystiggo (rozanolixizumab-noli) is cleared for use with both antibody types, but not indicated for pediatric patients.
Reductions in disease severity seen for over 1.5 years with treatment
J&J’s regulatory application to the FDA, which was placed under priority review early this year, was backed by data from the Phase 3 VIVACITY-MG3 trial (NCT04951622). In that trial, Imaavy was given on top of standard care for 24 weeks, or about six months. Treatment led to reductions in disease severity compared with a placebo when given alongside standard care in adults with gMG.
Such reductions were assessed using the MG Activities of Daily Living (MG-ADL) scale, a patient-reported metric of symptom severity. According to J&J, these MG-ADL improvements translate to participants regaining daily functions like chewing, swallowing, speaking, and breathing.
Use of the therapy also led to rapid and sustained reductions in anti-AChR and anti-MuSK antibodies.
Nicholas J. Silvestri, MD, a practicing neurologist and professor of neurology at the University of Buffalo, noted that “patients experienced substantial symptom relief and lasting disease control that translated into better daily function and did not fade over 24 weeks.”
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.
Reductions in disease severity with Imaavy in the main part of the trial have also been sustained for up to 20 months, or longer than 1.5 years, in an ongoing open-label extension, in which all participants are receiving Imaavy.
“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,” Silvestri said.
Data from another ongoing Phase 2/3 study called Vibrance-MG (NCT05265273) have similarly shown Imaavy’s ability to lower self-reactive antibody levels and ease disease severity in adolescent patients.
Across studies, Imaavy has shown a consistent safety profile. Its most common side effects include respiratory tract infections, swelling in the hands, legs, or feet, and muscle spasms. Imaavy should not be used by people who have had serious reactions to it or any of its ingredients, per its label.
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