Phase I study of mitozolomide on a once daily for 5 days schedule.

In a phase I study mitozolomide was given on a once daily for 5 days schedule to 18 patients with a variety of malignancies. Non-hematological toxicity was negligible. Significant myelosuppression occurred at a total dose as low as 62.5 mg/m2 per course. In particular, thrombocytopenia, which was unpredictable, precluded dose increments beyond 15 mg/m2 per day (or a total of 75 mg/m2). Antitumor effects were not observed. The 5-day schedule of mitozolomide appears to have no advantage over administration once every 3-4 weeks, and may even be more dangerous than the latter schedule.