2-chlorodeoxyadenosine (cladribine) in the treatment of patients with chronic lymphocytic leukemia 55 years old and younger

The aim of the study was to determine the effectiveness of 2-chlorodeoxyade nosine (2-CdA) administered in 2-h i.v. infusions in the treatment of B cel l chronic lymphocytic leukemia (B-CLL) in patients 55 years old and younger . One hundred and thirteen patients received three to 10 courses of 2-CdA a dministered at a dose of 0.12 mg/kg daily for 5 consecutive days. Sixty-sev en patients were previously treated with chlorambucil and prednisone, COP a nd some of them also with CHOP, and 46 were untreated. Complete remission ( CR) was achieved in 21 (18.6%) (19 in untreated and two in previously treat ed) patients and partial response (PR) in 38 (33.6%) (23 and 15, respective ly) giving an overall response rate in 52.2%. The differences in CR and ove rall response rate between previously treated and untreated patients were s tatistically significant (P = 0.001). Surface immunophenotyping by flow cyt ometry using dual-color staining on the peripheral blood and/or bone marrow was performed in 38 patients who responded to 2-CdA therapy. Residual dise ase had been demonstrated in five out of 17 (29.4%) patients who were in CR and in all 21 investigated PR patients. 2-CdA-induced thrombocytopenia occ urred in 24 (35.8%) of previously treated and in 13 (28.3%) previously untr eated patients (P = NS). Neutropenia was observed in eight (11.9%) and in f ive (10.9%) patients, respectively (P = NS). Severe infections, including p neumonia and sepsis, occurred more often in previously treated (44.8%) than untreated patients (26.1%) (P < 0.05). Twenty-seven (23.9%) patients died, 11 because of infections, five because of drug-related thrombocytopenia an d hemorrhage, one because of second malignancy and eight because of disease progression. In conclusion, our results indicate that 2-CdA is an effectiv e agent in younger patients with B-CLL, especially used as a first line the rapy.