Fludarabine treatment in B-cell chronic lymphocytic leukemia: response, toxicity and survival analysis in 47 cases

Fludarabine monophosphate (FAMP) is a purine analog with specific therapeutic activity in B-cell chronic lymphocytic leukemia (CLL). Its current use as front-line therapy of CLL is still a matter of debate both because of the controversial results of the clinical trials so far reported and because of the toxicity profile of the drug. In order to contribute to clarifying the possible role of FAMP, we report a retrospective analysis of the results obtained with the purine analog in CLL patients in different phases of the disease.

Forty-seven patients affected by advanced CLL, 36% untreated, 31.9% relapsed and 31.9% resistant, were treated with FAMP 25 mg/m2/day, either for 4 days every 3 weeks in 29 cases, or for 5 days every 4 weeks in 18. The median number of FAMP cycles was 6 (range 2-11). Response was defined according to total tumor mass (TTM) score reduction and toxicity was expressed according to WHO grading criteria. The median follow-up of the series was 13 months from the beginning of FAMP therapy.

Out of 47 evaluable patients the response rate was 74.4%, with 34% complete response (CR). The overall response rate was 94%, 80% and 46.6% in untreated, relapsed and resistant cases, respectively; a significantly higher number of responses was associated with no previous treatment and number of FAMP cycles. Fifty-three percent of all cases and 58.8% of untreated ones did not experience any toxicity. Treatment-related side effects were mainly autoimmune phenomena in untreated patients and infectious complications in treated ones. One heavily pre-treated patient died because of neurologic complications. Median time to re-treatment was18 months (range 1-30) and was influenced by age and previous treatment. The overall median survival was 35.7 months with a significantly higher proportion of surviving cases among RAI 0-II stages, responders and patients receiving more than 5 FAMP cycles.

The present report confirms the high efficacy of FAMP in previously pre-treated cases with acceptable toxicity and encourages its use as front-line treatment provided that the results of randomized trials demonstrate its superiority over conventional chemotherapy. The possible development of autoimmune phenomena should, however, be considered seriously.