Phase I trial of PN401, an oral prodrug of uridine, to prevent toxicity from fluorouracil in patients with advanced cancer.

Abstract

Oral PN401 is well tolerated and total doses of 6 g every 6 hours yield sustained levels of URD in the target range of 50 mumol/L. The MTD of FU with PN401 rescue is 1,000 mg/m2 and the recommended dose for phase II trials is 800 mg/m2 given weekly for 6 weeks with dose escalation. Further studies to define better the appropriate interval for PN401 rescue and the appropriate dose of FU when given with biochemical modulation, such as with leucovorin, are indicated.