Published in:
01-12-2014 | Original Article
Busulfan in patients with polycythemia vera or essential thrombocythemia refractory or intolerant to hydroxyurea
Authors:
Alberto Alvarez-Larrán, Luz Martínez-Avilés, Juan Carlos Hernández-Boluda, Francisca Ferrer-Marín, María Luisa Antelo, Carmen Burgaleta, M. Isabel Mata, Blanca Xicoy, Alejandra Martínez-Trillos, M. Teresa Gómez-Casares, M. Antonia Durán, Bárbara Marcote, Agueda Ancochea, Alicia Senín, Anna Angona, Montse Gómez, Vicente Vicente, Francisco Cervantes, Beatriz Bellosillo, Carles Besses
Published in:
Annals of Hematology
|
Issue 12/2014
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Abstract
Therapeutic options for patients with polycythemia vera (PV) and essential thrombocythemia (ET) resistant or intolerant to hydroxyurea are limited. Busulfan is effective as first-line therapy, but there is scarce information on this drug as second-line treatment. The efficacy of busulfan in patients with advanced PV or ET refractory or intolerant to hydroxyurea was assessed in 36 patients (PV n = 15, ET n = 21) treated for a median of 256 days. Complete hematological response (CHR) was achieved in 83 % of patients, after a median time of 203 days (range 92–313). The probability of sustained CHR at 1 and 2 years was 87 and 62 %, respectively. Time to CHR was shorter in patients treated with ≥14 mg of busulfan per week than with lower doses (141 versus 336 days, p = 0.01). Partial molecular response was achieved in three out of nine (33 %) patients. Busulfan was stopped in 27 patients (75 %) due to CHR achievement in 18 cases (67 %), hematological toxicity in 8 cases (30 %), and disease transformation in 1 case. With a median follow-up of 721 days, six patients have died, with the probability of survival at 2 years being 85 %. The probability of thrombosis at 2 years was 11 %. Transformation into acute leukemia or myelodysplastic syndrome was observed in three cases, all of them in a JAK2V617F-negative clone carrying additional mutations. Busulfan, at a dose of 2 mg/day, is an effective option for elderly patients with PV or ET who fail to hydroxyurea, but a significant rate of transformation was observed.