FDA approves J&J's Imaavy (nipocalimab) as first-ever treatment for warm autoimmune haemolytic anaemia

Johnson & Johnson announced on 24 August 2026 that the US FDA has approved Imaavy (nipocalimab-aahu) for the treatment of warm autoimmune haemolytic anaemia (wAIHA) in adults and paediatric patients aged 12 and older who are currently or were previously treated with corticosteroids. It is the first-ever therapy cleared for the condition.

wAIHA is a rare, life-threatening autoantibody disease in which the immune system destroys red blood cells, causing severe anaemia, debilitating fatigue, blood clots and, in some cases, kidney failure. Imaavy is an immunoselective FcRn blocker designed to reduce pathogenic immunoglobulin G (IgG) autoantibodies while preserving B-cell function; it is infused every four weeks at a weight-based dose.

The approval is based on a pivotal Phase 2/3 study of 115 adults in which roughly three times as many patients on Imaavy achieved a durable haemoglobin response at Week 24 versus placebo, with a mean haemoglobin increase of 1 g/dL as early as Week 1 and improvements in FACIT-Fatigue scores. The most common adverse events were peripheral oedema, diarrhoea and fever. Imaavy was first approved in April 2025 for generalised myasthenia gravis, and the wAIHA nod extends its reach into haematology.

Source: Johnson & Johnson, 24 August 2026.