{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,4]],"date-time":"2026-03-04T16:29:32Z","timestamp":1772641772442,"version":"3.50.1"},"reference-count":32,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2025,5,23]],"date-time":"2025-05-23T00:00:00Z","timestamp":1747958400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Allergy"],"abstract":"<jats:sec><jats:title>Background<\/jats:title><jats:p>Limited data exist on the burden of myeloproliferative, lymphocytic and idiopathic subtypes of hypereosinophilic syndrome (M-HES, L-HES and I-HES) and the characteristics of patients with HES receiving biologic therapies. This analysis aimed to further characterize these subtypes and explore the impact of biologics in a real-world European setting.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>This was a <jats:italic>post hoc<\/jats:italic> subgroup analysis of a retrospective, non-interventional, chart review (GSK ID: 214657) across five European countries. Index date was first clinical visit during January 2015\u2013December 2019 (after or at time of HES diagnosis). Patients with HES aged \u22656 years with \u22651-year follow-up from index were included. Demographics, disease characteristics, diagnostic assessments, comorbidities, types of treatment, clinical manifestations, clinical outcomes and HES-related healthcare resource utilization were summarized for HES overall and subtypes. Oral corticosteroid (OCS) use and clinical manifestations\/outcomes were assessed 12-months pre- and post-biologics.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>The analysis included 280 patients with I-HES (<jats:italic>n<\/jats:italic>\u2009=\u2009155), M-HES (<jats:italic>n<\/jats:italic>\u2009=\u200966), L-HES (<jats:italic>n<\/jats:italic>\u2009=\u200942) and chronic eosinophilic leukemia (<jats:italic>n<\/jats:italic>\u2009=\u20092). The most common clinical manifestations were fatigue (54.2% I-HES, 52.4% L-HES, 42.4% M-HES), skin itch (36.4% M-HES, 35.7% L-HES, 33.5% I-HES) and pain (31.0% L-HES, 30.3% M-HES, 27.1% I-HES). Biologic use was highest with L-HES (64.3%), followed by I-HES (43.9%) and M-HES (34.8%). Clinical response rates were highest for the I-HES subtype (75.5%; 66.7% L-HES, 63.6% M-HES). Hospitalizations were highest for L-HES (45.2%; 30.3% M-HES, 25.8% I-HES). The annualized rate of OCS prescriptions reduced by 56.8% (0.44\u20130.19 per person-year) and the proportion of patients with \u22651 clinical response increased 3.6-fold (6.5%\u201323.4%) between the pre- and post-biologics periods.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>All HES subtypes had a substantial disease burden and were commonly associated with fatigue, skin itch and pain. I-HES appeared to be more responsive to treatment than L-HES and M-HES. Biologic use for HES led to more patients experiencing clinical responses and was OCS-sparing.<\/jats:p><\/jats:sec>","DOI":"10.3389\/falgy.2025.1605397","type":"journal-article","created":{"date-parts":[[2025,5,23]],"date-time":"2025-05-23T16:29:12Z","timestamp":1748017752000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":1,"title":["Steroid-sparing benefits of biologic use in hypereosinophilic syndrome and substantial disease burden across subtypes"],"prefix":"10.3389","volume":"6","author":[{"given":"Jeremiah","family":"Hwee","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lynn","family":"Huynh","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"suffix":"Jr","given":"Wilson","family":"da Costa","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Marc 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