ISSN 2997-1036
International Journal of Hematology | Vol. 3, No. 11, November 2012 | pp. 81–88
DOI: 10.46882/2012/IJH/000035
Original Article
Title: Cytogenetic and molecular response kinetics to low-dose hydroxyurea in essential thrombocythemia
Names of Authors: Y. Z. Ibrahim¹, A. B. Okafor², C. D. Danjuma³
Authors’ Affiliations: ¹Department of Haematology, Usmanu Danfodiyo University Teaching Hospital, Sokoto, Nigeria; ²Department of Pathology, University of Ibadan, Ibadan, Nigeria; ³Department of Haematology, University of Maiduguri, Maiduguri, Nigeria
Abstract: Essential thrombocythemia carries a risk of vascular thrombosis and transformation to myelofibrosis. This prospective study evaluated the clinical, hematological, and molecular kinetics of low-dose hydroxyurea (500 mg to 1000 mg daily) in 40 newly diagnosed, high-risk essential thrombocythemia patients harboring the JAK2 V617F mutation. Full blood counts were monitored bi-weekly, and JAK2 mutant allele burdens were quantified via real-time PCR at baseline and 12 months. Complete hematological response, defined by a platelet count below 400 × 10⁹/L and absence of symptoms, was achieved in 85.0% (34 of 40) of patients within a median of 6 weeks. The mean platelet count fell from 842.5 ± 124.0 × 10⁹/L to 354.2 ± 48.0 × 10⁹/L at month 12 (P < 0.001). However, the median JAK2 V617F allele burden showed only a minimal reduction, from 24.5% at baseline to 21.2% at month 12 (P = 0.34). Mild leukopenia occurred in 10.0% of patients. Low-dose hydroxyurea provides rapid and durable hematological control, but its short-term molecular clearance of the JAK2 clone is limited. Long-term studies are needed to determine if molecular non-response influences fibrotic transformation.
Keywords: Essential thrombocythemia, hydroxyurea, JAK2 V617F mutation, platelet count, molecular response
Manuscript Timeline: Received: August 14, 2012; Revised: September 20, 2012; Accepted: October 10, 2012; Published: November 15, 2012