FDA
FDA approves Fasenra for hypereosinophilic syndrome
Hypereosinophilic syndrome (HES) is a rare, potentially life-threatening group of disorders characterized by persistent eosinophilia and progressive organ damage. Treatment options have been limited, and many patients rely on chronic corticosteroids or immunosuppressive therapies to control disease flares.
On May 13, 2026, FDA approved Fasenra (benralizumab) for adults and adolescents aged 12 years and older with hypereosinophilic syndrome without an identifiable non-hematologic secondary cause. Fasenra was already approved for severe eosinophilic asthma and eosinophilic granulomatosis with polyangiitis, and this new indication expands its role across eosinophilic-driven diseases.
The approval was based on results from the phase 3 NATRON trial, which randomized 133 patients with HES to benralizumab or placebo administered subcutaneously every four weeks while continuing stable background therapy. Benralizumab significantly delayed time to first HES flare and reduced risk of first flare by 65% compared with placebo (hazard ratio, 0.35; P=.0024).
Investigators also evaluated fatigue, a common and debilitating symptom in HES. Key secondary endpoints included changes in PROMIS Fatigue scores and annualized flare rates.
The recommended dosage for HES is 30 mg administered subcutaneously every four weeks. The most common adverse effects in the NATRON study were headache, hypersensitivity reactions, and influenza-like illness.
Clinicians should monitor for hypersensitivity reactions, including anaphylaxis, and continue managing corticosteroid tapering carefully. Fasenra is not indicated for treatment of acute symptoms or sudden respiratory deterioration.
“The approval of benralizumab for the treatment of HES is an important step forward for patients, providing an additional treatment option,” said Princess U. Ogbogu, MD, division chief of Pediatric Allergy, Immunology, and Rheumatology at University Hospitals Rainbow Babies and Children’s Hospital and Case Western Reserve University and principal investigator of the NATRON trial. “The study demonstrated meaningful reduction in flares while addressing fatigue, a symptom that may impact patients.”
Source: AstraZeneca. (2026, May 14). Press release. Fasenra approved in US for hypereosinophilic syndrome