A phase I study of 5-azacytidine (NSC-102816).

5-Azacytidine was administered daily to 12 patients in a five-day schedule and to 15 patients in a weekly schedule as part of a phase I trial. The daily dose ranged from 50 mg/m2 to 158 mg/m2 and the weekly dose, from 200 mg/m2 to 633 mg/m2. The maximum total dose was 2000 mg in the daily schedule and 3775 mg in the weekly schedule. The major toxicity was gastrointestinal, with nausea and vomiting occurring in all patients in this study. Myelosuppression was less frequently encountered and appeared to be related to the increase in 5-azacytidine dose. Patients receiving 5-azacytidine in a weekly schedule of administration appeared to tolerate the drug better and to be more willing to continue their therapy.