Role of fludarabine as monotherapy in the treatment of chronic lymphocytic leukemia.

Abstract

Fludarabine is a synthetic adenine nucleoside analog that is indicated for first- and second-line treatment of chronic lymphocytic leukemia (CLL). The recommended intravenous (i.v.) dosage regimen is 25 mg/m2 daily for 5 consecutive days, with treatment cycles repeated every 28 days. In treatment-naïve patients with Binet stage B and C CLL, i.v. fludarabine produces superior responses to established first-line chemotherapies. Fludarabine produces a higher overall remission rate (60-70%) and longer progression-free survival (median approximately 20-30 months) than standard therapy with chlorambucil+/-prednisone and CAP (cyclophosphamide/doxorubicin/prednisone), and a comparable overall remission rate to CHOP (cyclophosphamide/vincristine/prednisone/doxorubicin). Fludarabine demonstrates high efficacy in both intermediate-risk (Rai stage I or II) and high-risk (Rai stage III or IV) patients. Furthermore, fludarabine is equally effective in younger (< or =65 years) and older (>65 years) patients. Fludarabine has significant activity as monotherapy in previously treated CLL, producing objective response rates of up to 94% in typically small-scale, noncomparative studies, with the majority of studies yielding rates of 30-60%. In a phase III multicenter study, the overall remission rate was significantly higher with fludarabine than with CAP (48 versus 27%) among the subset of treatment-refractory patients (n=96). For those patients who are refractory to or have relapsed following conventional chemotherapy (chlorambucil, CAP and CHOP), fludarabine can be considered the treatment of choice for second-line therapy. Moreover, patients with relapsed CLL may benefit from retreatment with fludarabine if they have previously demonstrated sensitivity to the drug. Standard-dose i.v. fludarabine has an established safety profile and comparable tolerability to anthracycline-based regimens (CAP and CHOP) in terms of its myelosuppressive and immunosuppressive effects, and offers the advantage of a markedly lower incidence of gastrointestinal effects (nausea/vomiting) and alopecia.