FDA Approves Imaavy for Long Term Treatment of Generalized Myasthenia Gravis

The FDA has approved Johnson and Johnson’s Imaavy (nipocalimab-aahu), the first and only FcRn blocker approved to treat adult and pediatric generalized myasthenia gravis (gMG) patients ages 12 and older in the United States, according to a news release.

Myasthenia gravis (MG) is a chronic autoantibody disease in which the immune system produces antibodies (anti-acetylcholine receptor [AChR], anti-muscle-specific tyrosine kinase [MuSK]) that attack proteins at the neuromuscular junction. This blocks nerve signaling to the muscles and the muscles cannot contract.

This disease affects approximately 700,000 people worldwide, with half of those patients being women. It is most often diagnosed in female pediatric patients and adult male patients, according to the news release.

Onset may be sudden, and symptoms can include weakness of the eye muscles, impaired speech and difficulty swallowing. As the disease advances, it’s referred to as generalized myasthenia gravis (gMG), which affects approximately 100,000 people in the United States. This disease also causes levels of immunoglobulin G (IgG) antibodies to rise, an indication that the body is fighting an infection, cancer or in this case, an autoimmune disorder.

“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,” Samantha Masterson, president and CEO of the Myasthenia Gravis Foundation of America, said in the 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.”

This approval is based on data from the Vivacity-MG3 study in which patients treated with Imaavy saw up to a 75% reduction in autoantibodies through 24 weeks of treatment.

Additionally, Imaavy plus standard of care (SOC) provided better disease control throughout 24 weeks compared with placebo plus SOC, as measured by improvement in the Myasthenia Gravis Activities of Daily Living (MG-ADL) score. This translates into patients regaining essential daily functions, such as chewing, swallowing, speaking and breathing. MG-ADL is an eight-item patient-reported outcome measure that assesses the impact of myasthenia gravis symptoms on daily activities.

“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,” Nicholas J. Silvestri, M.D., professor of neurology at University of Buffalo, said in the news release.

Imaavy is a monoclonal antibody that reduces the levels of IgG in the body by blocking the neonatal Fc receptor (FcRn). It is administered as an intravenous infusion only. Dosage amounts available include 300 mg/1.62 mL and 1,200 mg/6.5 mL. The recommended starting dose is 30 mg over at least 30 minutes. A maintenance dose of 15 mg/kg over at least 15 minutes for every two weeks after, according to the prescribing information. Prior to administration, Imvaay must be diluted with a 0.9% sodium chloride solution.

Safety was measured in 98 patients and the most common adverse reactions reported were respiratory tract infection (18%), peripheral edema (12%) and muscle spasms (12%).

Johnson and Johnson offers a patient support program called Imvaay withMe in the United States. Patients who are commercially insured may be eligible to receive their first infusion in as quickly as one week and pay as little as $0 per infusion.

An ongoing phase 2/3 Vibrance-MG study is studying the effects of Imvaay in pediatric gMG patients. It has already met its primary endpoint with a 69% reduction in IgG over 24 weeks.