Clinical features predict responsiveness to imatinib in platelet‐derived growth factor receptor‐alpha‐negative hypereosinophilic syndrome. Issue 6 (2nd March 2016)

• Record Type: Journal Article
• Authors: Khoury, P.; Desmond, R.; Pabon, A.; Holland‐Thomas, N.; Ware, J. M.; Arthur, D. C.; Kurlander, R.; Fay, M. P.; Maric, I.; Klion, A. D.
• Is Part Of: Allergy. Volume 71:Issue 6(2016:Jun.)
• Page Start: 803
• Page End: 810
• Publication Date: 2016-03-02
• Subjects: eosinophilia -- hypereosinophilic syndrome -- imatinib -- myeloid neoplasm -- PDGFRA‐negative; Allergy -- Periodicals; 616.97
• DOI: 10.1111/all.12843
• Languages: English
• ISSNs: 0105-4538

Abstract

Abstract: Background: With the exception of the presence of the FIP1L1‐PDGFRA fusion gene, little is known about predictors of imatinib response in clinically‐defined hypereosinophilic syndrome (HES). Methods: Subjects with FIP1L1‐PDGFRA ‐myeloid neoplasm (FP; n =12), PDGFRA ‐negative HES with ≥4 criteria suggestive of a myeloid neoplasm (MHES; n =10), or steroid‐refractory PDGFRA ‐negative HES with <4 myeloid criteria (SR; n = 5) were enrolled in a prospective study of imatinib therapy (NCT00044304: registered at clinicaltrials.gov). The primary outcome was an eosinophil count <1.5 × 109/L at one month and improvement of clinical symptoms. Clinical, molecular, and bone marrow responses to imatinib were assessed. A retrospective cohort of 18 subjects with clinically‐defined HES who received imatinib (300‐400 mg daily ≥ 1 month) were classified according to the criteria used in the prospective study. Results: Overall, imatinib response rates were 100% in the FP group ( n = 16), 54% in the MHES group ( n = 13) and 0% in the SR group ( n = 16). The presence of ≥ 4 myeloid features was the sole predictor of response. After ≥ 18 months in complete remission, imatinib was tapered and discontinued in 8 FP and 1 MHES subjects. Seven subjects (6 FP, 1 MHES) remain in remission off therapy for a median of 29 months (range 14–36). Conclusions: Clinical features of MHES predict imatinib response in PDGFRA ‐negative HES.