Johnson & Johnson's IMAAVY approved by FDA as first therapy for warm autoimmune hemolytic anemia

Regulatory approval

The U.S. Food and Drug Administration approved IMAAVY (nipocalimab-aahu) for treatment of warm autoimmune hemolytic anemia (wAIHA) in adults and pediatric patients 12 years of age and older who are currently or were previously treated with corticosteroids.

Clinical evidence

The Phase 2/3 ENERGY study used a stringent primary endpoint of durable hemoglobin (Hgb) response (Hgb ≥10 g/dL and an increase ≥2 g/dL sustained for at least 28 days, with criteria met by Week 16). The trial showed that approximately three times as many patients receiving the approved dose of IMAAVY achieved a durable Hgb response versus placebo by 24 weeks. Patients in the approved treatment group had a mean Hgb increase of 1 g/dL at Week 1, and a mean 3.5‑point higher FACIT‑Fatigue score versus placebo at Week 24. ENERGY results were presented at the European Hematology Association 2026 meeting in June 2026.

Safety and dosing

The approved dosing regimen is 30 mg/kg IV every 4 weeks. The safety profile in wAIHA was described as consistent with the established profile in generalized myasthenia gravis; the most common adverse reactions (≥10%) reported in wAIHA were peripheral edema, diarrhea and fever. Prescribing information warns of increased infection risk, infusion‑related reactions and hypersensitivity, and notes live vaccines should not be given to patients on therapy.

Trial design and development

ENERGY (NCT04119050) was a multicenter, randomized, double‑blind, placebo‑controlled Phase 2/3 study in which 115 adults were randomized approximately 1:1:1 to two nipocalimab dose schedules or placebo, followed by an open‑label extension of up to 144 weeks. IMAAVY was previously approved in the U.S. for generalized myasthenia gravis in April 2025.