A phase I and pharmacokinetic study of didox administered by 36 hour infusion. The Cancer Research Campaign Phase I/II Clinical Trials Committee

Br J Cancer. 1990 Mar;61(3):447-50. doi: 10.1038/bjc.1990.98.


Twelve patients were treated with didox, a new ribonucleotide reductase inhibitor, by 36 h infusion. The maximum tolerated dose was 6 g m-2, above which dose-limiting hepatic toxicity was observed. Patient tolerance was significantly better using the 36 h infusion compared to patients receiving the drug by a 30 min infusion; in particular, there were no reports of nausea or vomiting. No responses were seen in these patients. Detailed pharmacokinetics were performed at 6 g m-2 comparing the 36 h and 30 min infusions in four patients. Parent drug AUC values were lower for the 36 h infusion, 67.8 micrograms ml-1 h-1 compared to 232 micrograms ml-1 h-1 for the 30 min infusion. AUC values for the 3-hydroxy metabolite were much higher following the 36 h infusion: 55.4 compared to 18.6 micrograms ml-1 h-1. In contrast, the amide metabolite was not detected following the 36 h infusion, but AUC values of 23 micrograms ml-1 h-1 were seen after the 30 min infusion. The mean peak plasma level was 72 micrograms ml-1 following 6 g m-2 given by a 30 min infusion compared to 2.8 micrograms ml-1 following the prolonged infusion. Clearance was higher following the 36 h infusion: 97.6 versus 24.4 l h-1.

Publication types

  • Clinical Trial
  • Controlled Clinical Trial

MeSH terms

  • Adult
  • Aged
  • Drug Administration Schedule
  • Drug Evaluation
  • Female
  • Humans
  • Hydroxamic Acids / administration & dosage*
  • Hydroxamic Acids / adverse effects
  • Hydroxamic Acids / pharmacokinetics
  • Infusions, Intravenous
  • Male
  • Middle Aged
  • Neoplasms / drug therapy*
  • Ribonucleotide Reductases / antagonists & inhibitors*


  • Hydroxamic Acids
  • Ribonucleotide Reductases
  • 3,4-dihydroxybenzohydroxamic acid