---
title: Warm Autoimmune Hemolytic Anemia Gets Its First FDA-Approved Treatment
description: The FDA approved IMAAVY (nipocalimab), the first treatment developed specifically for warm autoimmune hemolytic anemia. What it does and how it works.
author: Dr Marina Nani (Editor-in-Chief)
updated: 2026-08-25T01:15:27.853Z
canonical: https://richhealthmagazine.com/article/waiha-first-fda-approved-treatment-imaavy-nipocalimab
categories: Longevity & Science
content_type: News
region: United States
publication: Rich Health Magazine
schema_type: Article
---

The Food and Drug Administration approved IMAAVY (nipocalimab) on August 24, 2026, as the first treatment developed and proven specifically for warm autoimmune hemolytic anemia, a rare disease in which a person's own immune system destroys their red blood cells. Johnson & Johnson, which makes the drug, said the approval followed an FDA Priority Review and covers adults and children 12 and older who are currently or previously treated with corticosteroids, the standard first-line drug for the disease.

Until now, doctors have had no medicine built for this disease. They have relied on corticosteroids, and when those fail, on drugs designed for other conditions and used off-label. For patients, that has often meant long stretches of relapse and side effects. Karen Jones, president and executive director of the patient group wAIHA Warriors, said living with the disease means "relentless fatigue and the constant uncertainty of not knowing what tomorrow will bring."

> "For the first time, our community has a treatment specifically for our disease."
> — Karen Jones, wAIHA Warriors

## The Immune System Attacks the Body's Own Red Blood Cells

In warm autoimmune hemolytic anemia, known as wAIHA, the immune system produces antibodies called IgG that attach to red blood cells and mark them for destruction. The result is severe anemia and fatigue that comes and goes but can be profound, along with a higher risk of blood clots, sudden kidney failure and infection. Johnson & Johnson says the disease is rare, affecting roughly 1 to 3 people per 100,000 each year, or about 1 in 8,000 people overall. It can start at any age, affects women and men, and becomes more common after age 50.

## Doctors Have Relied on Steroids and Drugs Borrowed From Other Diseases

Corticosteroids have long been the first treatment doctors reach for, and they help most patients within two to three weeks. But [lasting remission happens in only about a third of patients](https://pmc.ncbi.nlm.nih.gov/articles/PMC12371984/), and coming off steroids requires a slow, careful taper to avoid a relapse. For patients whose disease resists steroids or comes back, doctors often turn to rituximab, a drug that works by broadly wiping out the body's B-cells, the immune cells that produce antibodies. That approach is not specific to wAIHA and leaves patients with general immune suppression. Some patients have their spleen removed instead, which carries its own surgical and long-term infection risks. Relapse and side effects have been the recurring problem, because none of these options was designed for the disease itself.

## The Drug Clears the Antibodies Driving the Disease

IMAAVY blocks a receptor called FcRn, which the body uses to keep antibodies circulating. Blocking it clears IgG antibodies, including the ones attacking red blood cells, faster than the body would on its own, while leaving the immune system's B-cells able to keep working. It belongs to a class of FcRn blockers that also includes efgartigimod and rozanolixizumab, already approved for the neuromuscular disease myasthenia gravis. Doctors give IMAAVY as an intravenous infusion, at a dose of 30 mg per kilogram of body weight every four weeks.

## Patients Reached a Durable Response Three Times as Often as on Placebo

The approval rests on the ENERGY trial, a randomized, double-blind, placebo-controlled study of 115 adults, with full results presented at the European Hematology Association meeting in June 2026. The trial's main goal was a durable hemoglobin response: a hemoglobin level of at least 10 g/dL, with a rise of at least 2 g/dL, held for at least 28 days without needing rescue treatment. About three times as many patients on IMAAVY reached that response by 24 weeks compared with patients on placebo. Patients on the drug saw their hemoglobin rise by an average of 1 g/dL within the first week. Among patients who responded, the median time to a first response was 4.1 weeks on IMAAVY, compared with 12.1 weeks on placebo. On a standard fatigue scale called FACIT-Fatigue, patients on IMAAVY scored 3.51 points better than those on placebo at 24 weeks.

"Targeting the pathogenic IgG can meaningfully change the treatment paradigm for wAIHA," said David Kuter, a hematologist at Massachusetts General Hospital and Harvard Medical School who worked on the trial. More patients on IMAAVY "achieved a durable hemoglobin response compared with placebo, meaning their red blood cell levels went up and stayed up," Kuter said.

## The Trial Did Not Compare IMAAVY With Today's Off-Label Drugs

The ENERGY trial tested IMAAVY against a placebo, not directly against rituximab or the steroid regimens doctors already use off-label. That means how it compares with existing practice, in effectiveness or side effects, is not yet established. How it stacks up against the drugs doctors already reach for will take more experience and further studies to answer.

## The Side Effects Include Infection Risk, Swelling, Diarrhea and Fever

IMAAVY can raise the risk of infections, including serious ones, and can cause allergic or infusion-related reactions during or shortly after treatment. The side effects reported in 10 percent or more of patients in the trial were swelling in the arms or legs, diarrhea and fever.

This is IMAAVY's second FDA approval. Johnson & Johnson first won clearance for the drug in April 2025 for generalized myasthenia gravis, a neuromuscular disease unrelated to wAIHA. The company also runs a support program, IMAAVY withMe, that connects patients with a nurse navigator and cost-support options.

## FAQ

**Q: What is warm autoimmune hemolytic anemia?**
It is a rare disease in which the immune system makes antibodies that attach to and destroy the body's own red blood cells, causing anemia, fatigue and a higher risk of blood clots, kidney failure and infection.

**Q: How common is warm autoimmune hemolytic anemia?**
Johnson & Johnson estimates 1 to 3 new cases per 100,000 people each year, and about 1 in 8,000 people living with the disease. It can appear at any age and grows more common after 50.

**Q: How is IMAAVY given?**
As an intravenous infusion, at a dose of 30 mg per kilogram of body weight, once every four weeks.

**Q: What are the side effects of IMAAVY?**
The most common, reported in 10 percent or more of trial patients, were swelling in the arms or legs, diarrhea and fever. It can also raise the risk of infection and cause allergic or infusion-related reactions.

**Q: Is IMAAVY a cure for wAIHA?**
No. In the trial it helped more patients reach and hold a healthier red blood cell count than placebo did, but it is a managed, ongoing treatment rather than a cure.

**Q: Who can take IMAAVY for wAIHA?**
It is approved for adults and children 12 and older with wAIHA who are currently or have previously been treated with corticosteroids.