Imaavy becomes first FDA-approved treatment for warm autoimmune hemolytic anemia

On August 24, 2026, FDA expanded the approved use of Imaavy (nipocalimab-aahu) to include warm autoimmune hemolytic anemia (wAIHA) in adults and pediatric patients aged 12 years or older who are currently receiving or have previously received corticosteroids. Imaavy was originally approved in 2025 for generalized myasthenia gravis. This new indication makes it the first FDA-approved therapy specifically for wAIHA.

The approval fills a longstanding treatment gap. In wAIHA, immunoglobulin G (IgG) autoantibodies mark red blood cells for destruction, causing anemia, fatigue, and potentially serious complications. Management has relied largely on corticosteroids and other immunosuppressive therapies that were not specifically approved for the disease.

Imaavy blocks the neonatal Fc receptor (FcRn), which normally protects IgG from degradation. This reduces circulating IgG, including the autoantibodies driving red blood cell destruction, without depleting B cells. The drug offers a more targeted alternative to broad immunosuppression.

In the 24-week, randomized ENERGY trial, a durable hemoglobin response occurred in 24% of patients receiving the approved dose of 30 mg/kg IV every four weeks, compared with 8% receiving placebo. Durable response was defined as hemoglobin of at least 10 g/dL and an increase of at least 2 g/dL lasting 28 days or longer, without rescue therapy.

Imaavy can increase the risk of infection and may cause hypersensitivity and infusion-related reactions. Treatment should be delayed during an active infection, and live vaccines should be avoided. The most common adverse reactions in wAIHA were peripheral edema, diarrhea, and fever.

“Living with wAIHA often means relentless fatigue and the constant uncertainty of not knowing what tomorrow will bring,” said Karen Jones, president and executive director of wAIHA Warriors. “Patients may cycle through periods where they start to feel like themselves again — and then their hemoglobin drops, the exhaustion returns, and they’re back to square one. For the first time, our community has a treatment specifically for our disease.”

Source: Johnson & Johnson. (2026 Aug 24). FDA approves IMAAVY (nipocalimab-aahu) as first-ever treatment for warm autoimmune hemolytic anemia (wAIHA), representing a landmark advancement for patients