Johnson & Johnson has received FDA approval for IMAAVY, or nipocalimab-aahu, for adults and children aged 12 and older with warm autoimmune hemolytic anemia who are currently or were previously treated with corticosteroids.
The approval makes IMAAVY the first treatment approved specifically for warm autoimmune hemolytic anemia, or wAIHA, a rare and potentially life-threatening disease in which autoantibodies destroy red blood cells. The decision followed FDA Priority Review.
IMAAVY is an immunoselective therapy designed to block the neonatal Fc receptor, or FcRn, and reduce disease-driving immunoglobulin G autoantibodies while preserving B-cell function. Before the approval, treatment options for wAIHA included corticosteroids and immunosuppressants, which suppress the broader immune system rather than specifically targeting the IgG autoantibodies involved in the disease.
The FDA decision was supported by the Phase 2/3 ENERGY trial, a multicenter, randomized, double-blind, placebo-controlled study involving 115 adults. Participants were assigned to one of two nipocalimab dosing schedules or placebo, followed by an optional open-label extension period.
The primary endpoint was durable hemoglobin response, defined as hemoglobin of at least 10 g/dL and an increase of at least 2 g/dL from baseline for at least 28 days, without rescue therapy. Approximately three times as many patients receiving the approved 30 mg/kg intravenous dose every four weeks achieved a durable hemoglobin response by Week 24 compared with placebo.
Patients receiving IMAAVY showed a mean hemoglobin increase of 1 g/dL at Week 1. Among responders, median time to first hemoglobin response was 4.1 weeks with IMAAVY, compared with 12.1 weeks for placebo. The treatment group also had a 3.51-point higher mean improvement in FACIT-Fatigue score versus placebo at Week 24.
The most common adverse reactions in wAIHA were peripheral edema, diarrhea and fever. IMAAVY can increase the risk of infections and may cause hypersensitivity and infusion-related reactions.
The approval is IMAAVY’s second in the United States. The therapy was approved in April 2025 for generalized myasthenia gravis in adults and patients aged 12 or older who are positive for acetylcholine receptor or muscle-specific kinase antibodies.
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