The U.S. Food and Drug Administration has granted approval to Johnson & Johnson’s Imaavy (nipocalimabe-aahu) for the treatment of warm autoimmune hemolytic anemia (wAIHA), a rare blood disorder characterized by the immune system’s destruction of red blood cells.
The approval covers adults and pediatric patients aged 12 years or older who are either currently receiving or have previously been treated with corticosteroids. Imaavy, an FcRn blocker, works by reducing pathogenic immunoglobulin G (IgG) autoantibodies, addressing the underlying cause of the condition.
Clinical trial data from the Phase 2/3 ENERGY study, which enrolled 115 adults, demonstrated that patients receiving the approved 30 mg/kg dose achieved durable hemoglobin responses at approximately three times the rate of those given a placebo over 24 weeks. The trial’s primary endpoint required a hemoglobin concentration of at least 10 g/dL with an increase of at least 2 g/dL sustained for 28 days.
Additional efficacy metrics included a mean hemoglobin increase of 1 g/dL within the first week of treatment and a 3.5-point higher FACIT-Fatigue scale score at week 24 compared to placebo, indicating reduced fatigue. The most frequently reported adverse reactions were peripheral edema, diarrhea, and fever, consistent with the drug’s previously established safety profile for generalized myasthenia gravis.
Johnson & Johnson first secured FDA approval for Imaavy in April 2025 to treat generalized myasthenia gravis in patients aged 12 and older. The drug’s approval for wAIHA expands its therapeutic applications in autoimmune blood disorders.
