FDA Approves First Treatment for Warm Autoimmune Hemolytic Anemia

The Food and Drug Administration approved nipocalimab-aahu (Imaavy, Johnson & Johnson) Monday to treat warm autoimmune hemolytic anemia (wAIHA) in adults and pediatric patients 12 years of age and older who are currently or have been previously treated with corticosteroids. It is the first therapy approved specifically for wAIHA.

In wAIHA, pathogenic immunoglobulin G (IgG) autoantibodies bind to and destroy red blood cells, causing anemia and potentially serious complications. Treatment has traditionally relied on corticosteroids and other immunosuppressive therapies.

Nipocalimab-aahu is an immunoselective neonatal Fc receptor (FcRn) blocker that reduces circulating IgG autoantibodies and is administered by intravenous infusion.

FDA based its approval on the Phase 2/3 ENERGY study, a randomized, double-blind, placebo-controlled trial in adults with wAIHA. Approximately three times as many patients receiving the approved dose achieved a durable hemoglobin response by 24 weeks compared with placebo, the primary endpoint. Treated patients showed a mean hemoglobin increase of 1 g/dL at Week 1 and a 3.5-point improvement in FACIT-Fatigue score compared with placebo at Week 24. The most common adverse reactions were peripheral edema, diarrhea and fever.

Nipocalimab-aahu was first approved in the U.S. in April 2025 for generalized myasthenia gravis. It received Fast Track and Orphan Drug designations for wAIHA, and the application was granted Priority Review.