Oral fludarabine and cyclophosphamide as front-line chemotherapy in patients with chronic lymphocytic leukemia. The impact of biological parameters in the response duration

We tested the efficacy and safety of oral fludarabine and cyclophosphamide as front-line therapy in chronic lymphocytic leukemia (CLL) and assessed the influence of immunoglobulin variable region heavy chain (IgVH) gene mutation status, interphase cytogenetic abnormalities, and expression of ZAP-70 and CD38 on clinical outcome. Thirty-seven patients with previously untreated CLL received oral fludarabine (30 mg m(2)) and oral cyclophosphamide (250 mg m(2)) for three consecutive days every 4 weeks for six cycles. Eighteen patients had unmutated and 15 had mutated IgVH genes. Nine patients had the 'high risk' cytogenetic abnormality del(11q22.3) or del(17p13.1). Fifteen patients were ZAP-70-positive and eight patients were CD38-positive. Among the 35 valuable patients, 14 patients (40%) obtained a complete response and 13 (37%) a partial response. The median progression-free survival (PFS) was 23 months and median time to re-treatment (TTR) was 38 months. A significantly lower overall response rate (43% vs. 85%, p = 0.011), a shorter PFS (22 vs. 27 months, p = 0.015), and a shorter TTR (22 vs. 40 months, p = 0.031) were noticed in the 'high risk' cytogenetic abnormalities group; TTR was also shorter in IgVH-unmutated than in IgVH-mutated patients (26 vs. 41 months, p = 0.035). Hematologic toxicity included grade IV neutropenia (ten patients) and grade III/IV anemia (three patients). Gastrointestinal toxicity was mild and no patient required hospitalization. The oral combination of fludarabine and cyclophosphamide is an effective, safe, and well-tolerated regimen that, if confirmed with larger series, will be appropriate especially in patients with low risk biological parameters.