2-CHLORODEOXYADENOSINE THERAPY IN ADVANCED CHRONIC LYMPHOCYTIC-LEUKEMIA

The therapeutic potential of 2-chlorodeoxyadenosine (CdA) in patients with advanced chronic lymphocytic leukaemia (CLL) remains controversia l with response rates in clinical trials ranging from 44 to 67%. This report describes our experience with CdA in 22 CLL patients having alr eady undergone previous treatment. CdA was given by continuous intrave nous infusion at a dose of 4 mg/m(2)/day for 7 days (4 patients) or as 2-h intravenous infusions at a dose of 5.6 mg/m(2)/day for 5 days (18 patients). Partial (n=5) or complete (n=2) response was obtained in 7 cases. As compared to unresponsive patients, responding subjects rece ived CdA earlier in the cora se of their disease (mean interval betwee n diagnosis and CdA therapy 58 vs 102 months), were less thrombocytope nic at initiation of CdA (mean platelet count 165 x 10(9)/L vs 81 x 10 (9)/L) and experienced less severe neutropenia during the first course of therapy (mean minimal neutrophil count 1.55 x 10(9)/L vs 0.43 x 10 (9)/L). None of 6 patients with CLL refractory to fludarabine responde d to CdA. An evaluation of haematological toxicity during the first co urse of treatment showed grade 4 neutropenia (<0.5 x 10(9)/L in 7 case s and grade 4 thrombocytopenia (<25 x 10(9)/L) in one of 19 cases wher e the platelet count was greater than 25 x 10(9)/L at initiation of Cd A. In comparison with earlier reports, the present series of patients had received relatively heavy prior therapy, experienced more severe h aematological toxicity and demonstrated a lower total rate.