STOCKHOLM, Sweden, June 11, 2026
Johnson & Johnson has reported positive pivotal Phase 2/3 results for IMAAVY® (nipocalimab-aahu) in patients with warm autoimmune hemolytic anemia (wAIHA), a rare and potentially life-threatening autoimmune disease that currently has no FDA-approved treatment options. Data from the ENERGY study, presented at the European Hematology Association (EHA) 2026 Congress, demonstrated that IMAAVY achieved a statistically significant durable hemoglobin response, rapid onset of action, improved patient-reported fatigue, and reduced corticosteroid use compared with placebo. The findings represent a major advancement for patients living with wAIHA and further strengthen the growing clinical profile of Johnson & Johnson’s FcRn-targeting immunotherapy platform.
Pivotal ENERGY Study Meets Primary Endpoint with Rapid Hemoglobin Improvement
The randomized, double-blind, placebo-controlled Phase 2/3 ENERGY trial evaluated IMAAVY in adults with warm autoimmune hemolytic anemia, a condition in which pathogenic autoantibodies attack and destroy red blood cells, leading to severe anemia and debilitating fatigue. The study successfully met its primary endpoint of durable hemoglobin response, defined as achieving a hemoglobin concentration of at least 10 g/dL alongside an increase of at least 2 g/dL from baseline without the need for rescue therapy.
Patients treated with the 30 mg/kg dose of IMAAVY demonstrated approximately three times higher rates of durable hemoglobin response compared with placebo through 24 weeks. Importantly, patients experienced a mean hemoglobin increase of at least 1 g/dL within the first week of treatment, highlighting the therapy’s rapid onset of action. By Week 24, nearly two-thirds of treated patients achieved clinically meaningful hemoglobin targets, reinforcing the potential of IMAAVY to provide sustained disease control in a condition with limited therapeutic options.
Targeted Immunotherapy Improves Fatigue While Preserving Immune Function
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Beyond improvements in anemia, IMAAVY demonstrated meaningful benefits in several important secondary endpoints. Patients reported measurable reductions in fatigue symptoms as early as Week 2, with improvements maintained throughout the study period. The treatment also enabled greater reductions in corticosteroid use compared with placebo, addressing a key challenge for patients who often rely on long-term steroid therapy and face associated side effects. IMAAVY works through a differentiated mechanism by selectively targeting the neonatal Fc receptor (FcRn), reducing the levels of pathogenic immunoglobulin G (IgG) autoantibodies responsible for red blood cell destruction while preserving essential immune functions.
This immunoselective approach offers a potential advantage over broad immunosuppressive therapies currently used off-label in wAIHA. Safety findings were consistent with the established profile of IMAAVY in its approved indication, generalized myasthenia gravis, with the most commonly reported adverse events including peripheral edema, diarrhea, and fever.
FDA Priority Review Positions IMAAVY for Potential New Indication
The positive ENERGY trial results support Johnson & Johnson’s supplemental Biologics License Application (sBLA) for IMAAVY in warm autoimmune hemolytic anemia, which has already received FDA Priority Review. The therapy is currently approved for generalized myasthenia gravis but is being investigated across a broad range of autoimmune and rare disease indications, including Sjögren’s disease, systemic lupus erythematosus, chronic inflammatory demyelinating polyneuropathy, and maternal-fetal alloantibody disorders.
Experts believe the new data could significantly alter the treatment landscape for wAIHA, where patients currently depend on corticosteroids, immunosuppressants, and B-cell-targeting therapies without any specifically approved medicines. Affecting approximately one in 8,000 individuals, wAIHA remains a serious unmet medical need associated with increased risks of thrombotic events, infections, and organ complications. If approved for this indication, IMAAVY could become the first FDA-approved therapy specifically developed for warm autoimmune hemolytic anemia, offering a targeted and potentially transformative treatment option for patients worldwide.
Source: Johnson & Johnson press release
