FDA Approves Nipocalimab for Warm Autoimmune Hemolytic Anemia

The FDA approved nipocalimab-aahu (Imaavy; Johnson & Johnson) for the treatment of warm autoimmune hemolytic anemia (wAIHA) in adults and pediatric patients aged 12 years and older who are currently or previously treated with corticosteroids.

Nipocalimab is the first therapy ever proven safe and effective specifically for this rare, life-threatening disease. For pharmacists, the approval introduces a targeted intravenous option into a space where care has long depended on broad immunosuppression, bringing new counseling and infusion-management considerations into practice.¹

A Long-Standing Treatment Gap

In wAIHA, pathogenic immunoglobulin G (IgG) autoantibodies attach to and destroy red blood cells, causing severe anemia, profound fatigue, and a significantly increased risk of morbidity and mortality. Until now, treatment relied on corticosteroids and immunosuppressants; such therapies suppress the entire immune system without specifically targeting the IgG autoantibodies driving the disease.

The condition affects both women and men and can occur at any age, with incidence rising after age 50, and patients face elevated risk of serious complications, including venous thrombotic events, acute renal failure, and infection.^1-3

What the ENERGY Study Showed

The approval is based on the pivotal phase 2/3 ENERGY study (NCT04119050), a multicenter, randomized, double-blind, placebo-controlled trial in which 115 adults were randomized roughly 1:1:1 to nipocalimab 30 mg/kg every 4 weeks, 15 mg/kg every 2 weeks, or placebo, with concomitant stable corticosteroids or immunosuppressants permitted. Nipocalimab is an immunoselective neonatal Fc receptor (FcRn) blocker that reduces circulating IgG levels, including autoantibodies, while preserving B-cell function.^1,4,5

The primary end point was durable hemoglobin (Hgb) response, a stringent measure defined as Hgb of at least 10 g/dL and an increase of at least 2 g/dL from baseline sustained for at least 28 days—criteria met starting by week 16—without rescue therapy or new or increased steroids or immunosuppressants.

A durable Hgb response was achieved by 24% of patients on the approved 30 mg/kg every-4-week dose versus 8% on placebo, roughly 3 times as many. The mean Hgb increased by 1.1 g/dL as early as week 1 in the approved treatment group. Improvement in the Functional Assessment of Chronic Illness Therapy–Fatigue (FACIT-Fatigue) score favored nipocalimab, with a 3.4-point higher mean score versus placebo at week 24, where higher scores indicate less fatigue.^1,4

Safety and Counseling Considerations

In ENERGY, nipocalimab showed a safety profile consistent with its established profile in generalized myasthenia gravis. The most common adverse reactions occurring in at least 10% of patients with wAIHA were peripheral edema, diarrhea, and pyrexia.

Because FcRn blockade can increase infection risk, pharmacists should counsel patients to report signs of infection promptly, including fever, chills, cough, sore throat, or burning on urination, and should note that patients on nipocalimab should not receive live vaccines. Hypersensitivity and infusion-related reactions have also been reported during or after administration, warranting monitoring around infusions.^1,4

Access and Practice Impact

Nipocalimab is supplied as single-dose vials for intravenous injection, and the approved regimen is 30 mg/kg every 4 weeks. This is the second approval for the agent, which was first cleared in April 2025 for generalized myasthenia gravis in patients 12 years and older who are AChR or MuSK antibody positive. Johnson & Johnson has said its Imaavy withMe program offers patient support, including educational resources, a nurse navigator, and cost-support options regardless of insurance type—relevant context for pharmacists fielding access questions.^1,5,6

REFERENCES

1. FDA approves IMAAVY (nipocalimab-aahu) as first-ever treatment for warm autoimmune hemolytic anemia (wAIHA), representing a landmark advancement for patients. News release. Johnson & Johnson. Released August 24, 2026. Accessed August 25, 2026. https://www.jnj.com/media-center/press-releases/fda-approves-imaavy-nipocalimab-aahu-as-first-ever-treatment-for-warm-autoimmune-hemolytic-anemia-waiha-representing-a-landmark-advancement-for-patients

2. Tranekær S, Hansen DL, Frederiksen H. Epidemiology of secondary warm autoimmune haemolytic anaemia—a systematic review and meta-analysis. J Clin Med. 2021;10(6):1244. doi:10.3390/jcm10061244

3. Fattizzo B, Barcellini W. New therapies for the treatment of warm autoimmune hemolytic anemia. Transfus Med Rev. 2022;36(4):175-180. doi:10.1016/j.tmrv.2022.08.001

4. Fattizzo B, Murakhovskaya I, Ueda Y, et al. Nipocalimab for warm autoimmune hemolytic anemia: results from the phase 2/3 randomized, double-blind ENERGY study. Presented at: European Hematology Association 2026 Congress; June 2026. https://library.ehaweb.org/eha/2026/eha-2026/4206854/bruno.fattizzo.nipocalimab.for.warm.autoimmune.hemolytic.anemia.results.from.html

5. A study to evaluate the efficacy and safety of nipocalimab in participants with warm autoimmune hemolytic anemia. ClinicalTrials.gov Identifier: NCT04119050. Last Updated July 31, 2026. Accessed August 25, 2026. https://clinicaltrials.gov/study/NCT04119050

6. Johnson & Johnson receives FDA approval for IMAAVY^TM (nipocalimab-aahu), a new FcRn blocker offering long-lasting disease control in the broadest population of people living with generalized myasthenia gravis (gMG). News release. Johnson & Johnson. Released April 30, 2025. Accessed August 25, 2026.