Prolonged administration of oral etoposide in non-small-cell lung cancer: a phase II trial.

Abstract

The trial was undertaken to investigate the activity and toxicity of a prolonged schedule of oral etoposide in the treatment of advanced non-small-cell lung cancer (NSCLC). Between March 1989 and August 1990, 25 patients with advanced NSCLC were treated with oral etoposide 50 mg/m2/d for 21 consecutive days, repeated every 28 to 35 days. The median patient age was 60 years (range, 38 to 84 years); male:female ratio was 12:13. Eight patients had stage IIIB disease; 17 had stage IV. Seventy-six percent of patients had Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. No patient had received previous chemotherapy with standard agents; nine patients had received previous or concurrent radiation therapy. Plasma etoposide concentrations were measured to estimate etoposide bioavailability and kinetics. Five of 22 patients (23%; 95% confidence interval [CI], 10% to 43%) had partial responses. Median response duration was 5 months (range, 2 to 6 months). Four of five responders were female. Besides alopecia, which occurred in all patients, myelosuppression was the most common toxicity, but was mild or moderate in most patients. Median leukocyte nadir during course 1 was 3,200/microL; only four of 69 courses produced a leukocyte nadir less than 1,000/microL. Severe thrombocythemia (less than 75,000/microL) did not occur. Gastrointestinal toxicity was uncommon. Median peak etoposide concentration was 3.4 micrograms/mL. A mean serum etoposide concentration greater than 1 microgram/L was maintained for more than 13 hours; the plasma concentration-time curve (AUC) was estimated to be 90% of that predicted after an identical dose of etoposide given intravenously. Etoposide given by this dose and schedule has moderate activity as first-line systemic therapy for advanced NSCLC. In previously untreated patients, chronic oral etoposide is well tolerated, and incorporation into combination regimens should be feasible. Etoposide bioavailability may be increased at lower oral doses.