Chronic daily administration of oral etoposide--a phase I trial.

Abstract
In this phase I study, we administered etoposide (VP-16) orally for 21 consecutive days to patients with advanced refractory cancers. All patients had received previous chemotherapy, and 50% of patients had received more than one combination regimen. When given for 21 consecutive days, the maximum-tolerated dose of oral VP-16 was 50 mg/m2/d. Myelosuppression was the dose-limiting toxicity, and occurred between days 21 and 28. In most patients, blood counts had recovered sufficiently by day 35 to begin another 3-week course. WBC count nadirs of less than 1,000/microL occurred in four of 20 courses at this dose, and three patients required hospitalization for treatment of neutropenia and fever. Alopecia occurred in most patients; gastrointestinal (GI) and other toxicities were uncommon. Five of 16 patients with measurable tumor had partial responses of 3 to 4 months duration. Four of these five patients had malignancies that are usually unresponsive to VP-16 when administered by previously investigated sche...