title: A phase 1 and pharmacokinetic study of didox: a ribonucleotide reductase inhibitor.
abstract: A phase 1 study of a new ribonucleotide reductase inhibitor, didox, was performed by administration of escalating doses of the drug by slow i.v. injection. Thirty-four patients with unresponsive metastatic carcinoma received the drug. There were 13 escalations of dosage, from a starting dose of 192 mg m-2 to 10 g m-2. Dose limiting toxicity was encountered at 7.5 g m-2 where disturbances of hepatic and renal function were observed, in addition to severe gastrointestinal toxicity. Pharmacokinetic studies showed that a peak level of didox was achieved within 5 minutes of injection. At 1,728 mg m-2 the data best fitted a 2 compartment open model, with a mean serum alpha t1/2 of 5.2 min, with a beta t1/2 of 41.3 min. Less than 10% of the drug was excreted unchanged in the urine and the majority of this excretion was within 6 h. Didox can therefore be safely given by slow i.v. injection at a dose of 6 g m-2.
mesh_terms: D000328:Adult; D000368:Aged; D004341:Drug Evaluation; D005260:Female; D006801:Humans; D006877:Hydroxamic Acids / Q000009:adverse effects / Q000493:pharmacokinetics / Q000627:therapeutic use*; D008111:Liver Function Tests; D008297:Male; D008875:Middle Aged; D009325:Nausea / Q000139:chemically induced; D009362:Neoplasm Metastasis; D009369:Neoplasms / Q000097:blood / Q000188:drug therapy*; D012264:Ribonucleotide Reductases / Q000037:antagonists & inhibitors*; D014555:Urination Disorders / Q000139:chemically induced; D014839:Vomiting / Q000139:chemically induced
chemical_list: D006877:Hydroxamic Acids; D012264:Ribonucleotide Reductases; C035419:3,4-dihydroxybenzohydroxamic acid