Cladribine combined with mitoxantrone in the treatment of blastic phase of chronic myeloid leukemia.

A phase II clinical study was performed to evaluate the effectiveness and toxicity of cladribine (2-CdA) combined with mitoxantrone (CM regimen) in the treatment of chronic myeloid leukemia in blastic phase (CML BP). A total of 12 adult patients with CML BP were included in this study. 2-CdA was given at a dose 0.12 mg/kg in 2-hour iv infusion on days 1-5 and mitoxantrone 10 mg/m2 i.v. day 1. The cycles were repeated at 4 week intervals in most cases. Complete remission (CR) was defined as the presence of < 5% of blasts in a normo- or hypercellular bone marrow in addition to normal peripheral blood counts and with normal physical examination. A partial response (PR) required normal peripheral blood counts but 5 to 25% marrow blasts. Toxicity was assessed according to WHO criteria. The patients received 21 courses of CM (median 2, range 1-3). Of 12 patients only 2 (17%), achieved PR. Responses were observed in patients with myeloid BP, after 3 and 2 courses, respectively. Myelosuppression was the main toxicity. Four patients (33.3%) had grade 3 or 4 neutropenia and 3 (25%) had grade 3 or 4 thrombocytopenia. Infections occurred in 4 patients (33.3%) and 2 of them died of sepsis shortly after CM treatment. This preliminary results in a small group of patients suggest that CM programme has limited value in pre-treated patients with CML BP. However, this regimen may be used as palliation in the end stage of disease.