SPRING HOUSE, PA — Johnson & Johnson (NYSE: JNJ) secured U.S. Food and Drug Administration approval for IMAAVY to treat warm autoimmune hemolytic anemia in patients 12 and older who are currently or were previously treated with corticosteroids, establishing the first FDA-approved therapy specifically for the rare, potentially life-threatening blood disorder.
The approval followed an FDA Priority Review and gives Johnson & Johnson a second approved indication for IMAAVY, or nipocalimab-aahu, after the drug received U.S. approval in April 2025 for certain patients with generalized myasthenia gravis.
Warm autoimmune hemolytic anemia, or wAIHA, occurs when immunoglobulin G autoantibodies attach to and destroy red blood cells. The disease can cause severe anemia and fatigue and is associated with increased morbidity and mortality.
IMAAVY is designed to target and reduce pathogenic IgG autoantibodies while preserving B-cell function. Previously available treatments for wAIHA included corticosteroids and immunosuppressants rather than an FDA-approved drug specifically indicated for the disease.
The approval was supported by Johnson & Johnson’s randomized, placebo-controlled Phase 2/3 ENERGY study. The trial’s primary endpoint measured durable hemoglobin response, assessing whether increases in patients’ hemoglobin levels were sustained over time.
About three times as many patients receiving the approved IMAAVY dose achieved a durable hemoglobin response through 24 weeks compared with placebo, according to the company. Patients in the treatment group recorded a mean hemoglobin increase of 1 gram per deciliter at Week 1.
IMAAVY-treated patients also had a 3.5-point higher mean FACIT-Fatigue score than those receiving placebo at Week 24, with higher scores indicating less fatigue.
“The Phase 2/3 ENERGY study demonstrates that targeting pathogenic IgG can meaningfully change the treatment paradigm for wAIHA,” David Kuter, a physician at Massachusetts General Hospital and professor of medicine at Harvard Medical School, said. “More patients treated with IMAAVY achieved a durable hemoglobin response compared with placebo — meaning their red blood cell levels went up and stayed up.”
The drug’s safety profile in the ENERGY study was consistent with its established profile in generalized myasthenia gravis, Johnson & Johnson reported. The most common adverse reactions, occurring in at least 10% of wAIHA patients treated with IMAAVY, were peripheral edema, diarrhea and fever.
The approval expands Johnson & Johnson’s use of IMAAVY beyond generalized myasthenia gravis, where it is approved for adult and pediatric patients 12 and older who are acetylcholine receptor- or muscle-specific kinase-antibody positive.
David M. Lee, Johnson & Johnson’s global immunology therapeutic area head, called the wAIHA authorization the drug’s “second approval” and said the company sees IMAAVY as a potential treatment for patients whose disease remains uncontrolled.
Johnson & Johnson also operates its IMAAVY withMe support program for patients prescribed the drug, providing educational resources, nurse-navigation services and information about cost-support options.
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