Combination Chemotherapy with Fludarabine, Cyclophosphamide and Mitoxantrone (FCM) Induces a High Response Rate in Previously Untreated CLL.

Treatment with FCM results in responses rates of 60% in relapsed or refractory CLL patients. Against this background, we started a trial of FCM in untreated patients diagnosed with CLL younger than 65 yrs. FCM consisted of fludarabine 25 mg/m² i.v. on days 1 to 3, cyclophosphamide 200 mg/m² on days 1 to 3, and mitoxantrone 6 mg/m² i.v. on day 1, given at a 4-week intervals up to six courses. Patients received support with G-CSF and prophylaxis with cotrimoxazole. Response was assessed two months after treatment and included bone marrow and minimal residual disease (MRD) analysis by four-color flow cytometry and PCR. Out the 64 evaluable patients (74% male, median age 58 years), 83% were in advanced (B and C) Binet’s clinical stage and 62% had increased (>20%) ZAP-70 expression. FISH analysis disclosed del(13q) in 25%, +12 in 22%, del(17p) in 10% of cases and del(11q) in 23%. Eighty-three per cent of the patients received the entire planed treatment. Overall response rate was of 88%. MRD-negative CR was obtained in 24%, MRD-positive CR in 23%, nPR 22% and PR 11%. Two out of 14 nPR cases were MRD-negative. Duration of response was 55% at 36 months. Initial parameters associated with CR achievement were the presence of del(17p) (p=0.003), increased serum LDH (P=0.014), and splenomegaly (p=0.04). Hematological toxicity was mild, with grade III-IV neutropenia in 8% of the cases, and moderate infections in 12%. Two patients developed fulminant B hepatitis, one of them dying as a direct consequence of it. In conclusion, in untreated CLL patients, FCM induces a high CR rate, including an important number of MRD negative CR. This places FCM among the most effective regimens for CLL and serves to build up a new immunochemotherapy regimen for CLL (R-FCM) currently under investigation.