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Clinical features predict responsiveness to imatinib in platelet‐derived growth factor receptor‐alpha‐negative hypereosinophilic syndrome
Author(s) -
Khoury P.,
Desmond R.,
Pabon A.,
HollandThomas N.,
Ware J. M.,
Arthur D. C.,
Kurlander R.,
Fay M. P.,
Maric I.,
Klion A. D.
Publication year - 2016
Publication title -
allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.363
H-Index - 173
eISSN - 1398-9995
pISSN - 0105-4538
DOI - 10.1111/all.12843
Subject(s) - hypereosinophilic syndrome , imatinib , medicine , alpha (finance) , platelet derived growth factor , immunology , eosinophilia , platelet derived growth factor receptor , receptor , growth factor , surgery , myeloid leukemia , construct validity , patient satisfaction
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.