Background

Imaavy (nipocalimab-aahu) is a prescription medication approved by the FDA in April 2025 for the treatment of generalized myasthenia gravis (gMG) in adults and adolescents aged 12 years and older who are positive for anti-acetylcholine receptor (AChR) or anti-muscle-specific kinase (MuSK) antibodies. It belongs to a class of drugs known as neonatal Fc receptor (FcRn) blockers. By inhibiting FcRn, Imaavy prevents the recycling of IgG antibodies, leading to their accelerated degradation. This mechanism reduces pathogenic autoantibodies that contribute to neuromuscular junction dysfunction, thereby improving muscle strength and reducing symptoms in gMG patients.

The medication is administered intravenously, starting with an initial dose of 30 mg/kg infused over at least 30 minutes, followed by maintenance doses of 15 mg/kg every two weeks. Infusions must be diluted in 0.9% sodium chloride and delivered through a 0.2-micron filter. Common side effects include respiratory tract infections, peripheral edema, muscle spasms, and infusion-related reactions such as headache, fatigue, rash, nausea, and chills. Serious risks include hypersensitivity reactions, including anaphylaxis, and increased susceptibility to infections. Imaavy is contraindicated in patients with a history of severe hypersensitivity to nipocalimab or its components.

FDA approval was based on clinical trials such as the Phase 3 Vivacity-MG3 study, which demonstrated significant improvements in MG symptoms and daily functioning.

Policy (Criteria)

Coverage of these drugs is provided when the criteria below is met and for non-preferred products there has been a trial and failure of preferred therapy (if applicable).

Nipocalimab may be considered MEDICALLY NECESSARY for the following condition(s):

Generalized Myasthenia Gravis

1. Member meets FDA approved age requirement
2. Prescribed by or in consultation with a neurologist
3. Member is anti-acetylcholine receptor (AChR) antibody positive or anti-muscle specific tyrosine kinase (MuSK) antibody positive
4. One of the following:
   1. Trial and failure, contraindication, or intolerance to two immunosuppressive therapies (such as glucocorticoids, azathioprine, cyclosporine, mycophenolate mofetil, methotrexate, tacrolimus)
   2. Trial and failure, contraindication, or intolerance to one immunosuppressive therapies (such as glucocorticoids, azathioprine, cyclosporine, mycophenolate mofetil, methotrexate, tacrolimus) AND trial and failure, contraindication, or intolerance to one of the following:
      1. chronic plasmapheresis/plasma exchange
      2. intravenous immunoglobulin (IVIG) rituximab (if member is MuSK antibody positive)

Continuation of therapy is considered MEDICALLY NECESSARY when the following criteria are met:

Documentation of positive clinical response to therapy

Authorization duration: 12 months

References

1. U.S. Food and Drug Administration. (2025). Imaavy (nipocalimab-aahu) injection, for intravenous use: Prescribing information. Janssen Biotech, Inc. Retrieved from https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/761430s000lbl.pdf.
2. Imaavy [package insert]. Horsham, PA; Janssen Biotech, Inc., April 2025. Accessed May 2025.

Coding Section

Procedure and diagnosis codes on Medical Policy documents are included only as a general reference tool for each Policy. They may not be all-inclusive.

This medical policy was developed through consideration of peer-reviewed medical literature generally recognized by the relevant medical community, U.S. FDA approval status, nationally accepted standards of medical practice and accepted standards of medical practice in this community, technology assessment program (TEC) and other non-affiliated technology evaluation centers, reference to federal regulations, other plan medical policies, and accredited national guidelines.

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History From 2025 Forward