Princess U. Ogbogu, Florence Roufosse, Praveen Akuthota, Piotr Kuna, Matthieu Groh, Andreas Reiter, Akira Yokota, Salman H. Siddiqui, Pim Mutsaers, Bing LI, Paneez Khoury, Lila Bahadori, Artur Bednarczyk, Gerben Bouma, Laura G. Brooks, Jorge Ferreira, Hanna Grindebacke, Calvin N. Ho, Priya Jain, R. Palmer, Maria Jison, Amy D. Klion, on behalf of NATRON study group
Benralizumab, an eosinophil-depleting anti-IL-5 receptor α antibody, has demonstrated efficacy in severe eosinophilic asthma and eosinophilic granulomatosis with polyangiitis and shown promising results in hypereosinophilic syndrome (HES). NATRON was a randomized, double-blind placebo-controlled phase 3 study evaluating the efficacy and safety of benralizumab in FIP1L1::PDGFRA-negative HES. The primary endpoint was time to first HES flare. In total, 133 patients (median (range) age 51 (14-87) years, 62% female) were randomized (1:1) to receive benralizumab 30 mg every 4 weeks or placebo for 24 weeks, in addition to background therapy. Benralizumab significantly reduced the risk of first flare versus placebo (hazard ratio 0.35, 95% CI 0.18 to 0.69, P = 0.0024). Adverse events occurred in 64.2% and 66.7% of benralizumab- and placebo-treated patients, respectively. Benralizumab's safety was consistent with its known profile. These results demonstrate the efficacy and safety of add-on benralizumab in the treatment of HES. ClinicalTrials.gov identifier: NCT04191304 .