Fludarabine combination therapy for the treatment of chronic lymphocytic leukemia.

Fludarabine combination therapies have attained an increased popularity in the treatment of chronic lymphocytic leukemia (CLL). Among them, the combination of fludarabine/cyclophosphamide (FC) is by far the best regimen studied. Patients receiving FC at relapse show response rates (RRs) of 70%-94% with 11%-34% complete remission (CR) rates. In previously untreated patients with CLL, RRs of 64%-88% with 21%-46% CR rates were observed. The main side effects of FC are myelotoxicity and infections; most complications are reported as fever of unknown origin, infections of the upper respiratory tract, or herpes virus infection. There is probably a correlation between the higher dose of cyclophosphamide (> 750 mg/m2 per treatment course) and an increase in the number of severe infectious complications. Similar results were reported regarding the RRs and side effects of the combination of fludarabine/epirubicin. The triple combination of fludarabine/cyclophosphamide/mitoxantrone and fludarabine combinations with anti-CD20 (rituximab) or anti-CD52 (Campath-1H) antibody, might be even be more promising, since a relevant number of complete molecular remissions are achieved with these drugs. The precise role of fludarabine combinations within the overall treatment strategy remains to be determined. Our current recommendation is to use these combinations at relapse, while their use in first-line therapy should be investigated in clinical protocols. It remains to be shown whether patients with CLL achieve improved overall survival with these combination chemotherapies.