A comprehensive phase I and II clinical investigation of fludarabine phosphate.

This article presents data from the phase I and II clinical investigations of Fludara I.V. (fludarabine phosphate) (NSC 312887), which is the 5'-phosphorylated derivative of the novel antimetabolite, 9-beta-D-arabinofuranosyl-2-fluoroadenine. The comprehensive phase I evaluation of this new antitumor agent was conducted in 51 patients with advanced malignancy and 15 additional patients with aggressive forms of leukemia. Three separate phase I schedules of drug administration were examined. Myelosuppression was the dose-limiting toxicity on each schedule administered to patients with solid tumors. The drug was also examined at higher doses in patients with leukemia, and the dose-limiting toxicity on the high-dose protocol was unacceptable: serious neurologic toxicity. The observation of antitumor responses in patients with advanced non-Hodgkin's lymphoma prompted additional phase II investigation in patients with lymphoproliferative malignancy. The encouraging phase II data demonstrate that Fludara I.V. has promise for patients with low-grade histologic subtypes of non-Hodgkin's lymphoma and chronic lymphocytic leukemia. While interesting additional basic and clinical research projects regarding Fludara I.V. remain, it is important to expeditiously pursue approval for this drug. Adequate data exists to demonstrate that the low-dose administration of Fludara I.V. is both safe and effective. While the development of this drug has stimulated renewed interest in the clinical investigation of the chronic lymphoproliferative malignancies, the time for making it readily available to these patients has arrived.