Johnson & Johnson said on Monday the U.S. Food and Drug Administration approved its drug Imaavy for the treatment of warm autoimmune hemolytic anemia, a rare blood disorder characterized by the immune system destroying red blood cells.
The approval covers adults and pediatric patients aged 12 and older who have been treated with corticosteroids. The drug, known generically as nipocalimab-aahu, was granted Priority Review by the FDA and follows an earlier clearance in April 2025 for a different indication.
The decision is based on data from the Phase 2/3 ENERGY study, which enrolled 115 adults randomized to treatment or placebo. Patients receiving the approved 30 mg/kg dose of Imaavy were approximately three times more likely to achieve a durable hemoglobin response by 24 weeks compared with those on placebo.
Durable hemoglobin response was defined as a hemoglobin concentration of at least 10 g/dL and an increase from baseline of at least 2 g/dL sustained for at least 28 days. Patients in the treatment group showed a mean hemoglobin increase of 1 g/dL at Week 1, with a 3.5-point higher mean FACIT-Fatigue score versus placebo at Week 24.
Warm autoimmune hemolytic anemia affects roughly 1–3 new individuals per 100,000 annually. The most common adverse reactions reported in clinical trials included peripheral edema, diarrhea, and fever. Imaavy functions as an FcRn blocker, designed to reduce pathogenic immunoglobulin G autoantibodies linked to the disease.
