Cladribine with or without prednisone in the treatment of previously treated and untreated B-cell chronic lymphocytic leukaemia — updated results of the multicentre study of 378 patients

Between January 1992 and January 1999, we treated 378 B-chronic lymphocytic leukaemia (CLL) patients with cladribine (2-CdA), and 255 of the patients were also treated with prednisone. A total of 194 patients were previously untreated, and 184 had relapsed or refractory disease after previous other therapy. Complete response (CR) was obtained in 111 (29.4%) and partial response (PR) in 138 (36.5%) patients, giving an overall response (OR) rate of 65.9%. CR and OR were achieved more frequently in patients in whom 2-CdA was a first-line treatment (45.4% and 82.5% respectively) than in the pretreated group (12.5% and 48.4% respectively) (P < 0.0001). The median duration of OR for previously untreated patients was 14.7 months and for pretreated patients 13.5 months (P = 0.09). The median survival evaluated from the beginning of 2-CdA treatment was shorter in the pretreated group (16.3 months) than in the untreated group (19.4 months) (P < 0.0001). A total of 117 (63.9%) patients died in the pretreated group and 63 (32.6%) in the untreated group. In pretreated patients, 2-CdA + prednisone (P) and 2-CdA alone resulted in similar OR (51.0% and 45.0% respectively; P = 0.4). In contrast, in untreated patients, 2-CdA + P produced a higher OR (85.4%) than 2-CdA alone (72.1%) (P = 0.04). Infections and fever of unknown origin, observed in 91 (49.4%) pretreated and 74 (38.1%) untreated patients (P = 0.03), were the most frequent toxic effects. Our results indicate that 2-CdA is an effective, relatively well-tolerated drug, especially in previously untreated CLL.