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

A phase II clinical study was performed to evaluate the effectiveness and t oxicity of cladribine (2-CdA) combined with mitoxantrone (CM regimen) in th e 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 mitox antrone 10 mg/m(2) 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 p eripheral blood counts and with normal physical examination. A partial resp onse (PR) required normal peripheral blood counts but 5 to 25% marrow blast s. Toxicity was assessed according to WHO criteria. The patients received 21 courses of CM (median 2, range 1-3). Of 12 patient s only 2 (17%), achieved PR. Responses were observed in patients with myelo id BP, after 3 and 2 courses, respectively. Myelosuppression was the main t oxicity. 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%) a nd 2 of them died of sepsis shortly after CM treatment. This preliminary results in a small group of patients suggest that CM progr amme has limited value in pre-treated patients with CML BP. However, this r egimen may be used as palliation in the end stage of disease.