Fax +41 61 306 12 34 E-Mail karger@karger.ch www.karger.com Brief Communication Acta Haematol 2010;124:150–152 DOI: 10.1159/000319630 Clofarabine-Based Regimen as Useful Bridge Therapy for Allogeneic Transplantation in Myeloid Blast Crisis of Philadelphia-Positive Chronic Myeloid Leukemia Resistant to Imatinib and Dasatinib Massimo Breccia Saveria Capria Anna Paola Iori Robin Foà Giuliana Alimena Giovanna Meloni Department of Cellular Biotechnologies and Hematology, University La Sapienza, Rome, Italy side analogue (after ara-C) with efficacy against adult AML. Conventional treatment of BP-CML is notoriously un- satisfactory resulting in only transient responses and in marginal prolongations of survival once a BP has been diagnosed. Better results are achieved for the few patients who return to chronic phase and are successfully trans- planted. Response to treatment is the single most impor- tant prognostic factor for survival in BP. If BP evolves under imatinib treatment, a second-generation tyrosine kinase inhibitor (TKI; dasatinib or nilotinib) should be tried [6]. A recent update of the European LeukemiaNet provides provisional guidelines for second-generation TKI and defines suboptimal and failure response at dif- ferent time points [6]. In case of failure also for second- generation TKI, conventional approaches remain an op- tion, such as AML induction protocols with anthracy- clines and ara-C in myeloid BP. We hereby report a case of a CML patient who sud- denly progressed to myeloid BP during imatinib, failed dasatinib treatment and was successfully treated with a clofarabine-containing regimen prior to undergoing an allogeneic HSCT. Clofarabine, a 2-chloro-2  -fluoro-deoxy-9- - D-arabi- nofuranosyl-adenosine, has been approved for third-line treatment of relapsed or refractory acute lymphoblastic leukemia [1, 2]. It has also proved promising in pediatric patients with refractory or relapsed acute myeloid leuke- mia (AML) and in patients allowing them to proceed to an allogeneic hematopoietic stem cell transplant (HSCT) [3]. Moreover, the drug exhibits efficacy in adult AML and myelodysplastic syndrome. In both phase I and II investigations on clofarabine as a single agent, impressive clinical activity without neurotoxicity has been observed in patients with acute leukemias. In a phase II study, among 62 heavily pretreated patients, 20 (32%) respond- ed to treatment with clofarabine [4]; objective responses were also seen in blastic phase chronic myeloid leukemia (BP-CML; 7 out of 11 patients treated) [4]. Clofarabine effectiveness was also tested in association with other drugs, such as cytarabine (ara-C) and/or idarubicin, in relapsed or refractory acute leukemias, and showed, in an initial phase I–II study, an overall response rate of 38%. Response rates reached 87% in AML patients with longer first remission durations (12 months), suggesting a sig- nificant activity of clofarabine in this category of patients [5]. Hence, clofarabine appears to be the second nucleo- Received: June 2, 2010 Accepted after revision: July 21, 2010 Published online: October 11, 2010 Massimo Breccia, MD Department of Human Biotechnologies and Hematology Via Benevento 6 IT–00161 Rome (Italy) Tel. +39 06 857 951, Fax +39 06 4424 1984, E-Mail breccia  @  bce.uniroma1.it © 2010 S. Karger AG, Basel 0001–5792/10/1243–0150$26.00/0 Accessible online at: www.karger.com/aha