[A new purine analog in the treatment of hematologic malignancy. I. Fludarabine]

New purine analogues, fludarabine, 2-chlorodeoxyadenosine and 2-deoxycoformycin are remarkably active in generally incurable malignant lymphoproliferative disorders. The first part of the review summarises pharmacological properties, the mechanism of action, toxicity and clinical use of fludarabine. Major clinical experience with fludarabine has been obtained in patients with chronic lymphocytic leukaemia (CLL). In the studies in pretreated patients with CLL, the overall response rate was over 50%. In previously untreated patients with CLL response rate of 75-80% was recorded with a high ratio of complete responses. Fludarabine was found to be active agent in indolent lymphoma in phase I/II. Approximately 60% of patients with follicular lymphoma respond to fludarabine monotherapy. Combination of fludarabine with cytosine arabinoside (ara-C) is now successfully used in the treatment of acute myelogenous leukaemia (AML) and myelodysplastic syndrome (MDS). Other potential areas of use for fludarabine include hairy-cell leukaemia, Waldenström's macroglobulinaemia and mycosis fungoides. Myelosupression, especially leuko and lymphopenia is the major dose-limiting adverse effect of fludarabine. A long term reduction in CD4+ T cell count may be associated with an increased incidence of opportunistic infections. Other adverse effects such as nausea and vomiting or neurotoxicity are of mild to moderate severity when the recommended dosage is used.