BIOAVAILABILITY OF 50 AND 75-MG ORAL ETOPOSIDE IN LUNG-CANCER PATIENTS

This study was designed to determine the bioavailability of etoposide capsules administered orally at doses of 50 and 75 mg. Patients with i noperable or relapsed lung cancer, who had an Eastern Cooperative Onco logy Group (ECOG) performance status of 0-2 and adequate organ functio n, were eligible. A group of 17 patients were evaluable, all of whom w ere 75 years old or less, with an ECOG performance status of 0 or 1. T he bioavailability of oral etoposide was determined by measuring the a rea under the etoposide plasma concentration versus time curve (AUC) o n days 1, 10 and 21 during a once-daily regimen of oral administration for 21 consecutive days and comparing the value with the AUC achieved following intravenous administration 1 or 2 weeks after the last oral dose. The bioavailability of 50, 75 and 100 mg oral etoposide was det ermined in six, nine and two patients, respectively. The mean etoposid e bioavailabilities (+/- SD) of the 50-mg and 75-mg doses were 47 +/- 11% and 59 +/- 18%, respectively, and of the 100-mg dose in two patien ts were 51% and 33%, respectively. There was no statistically signific ant difference in bioavailability between the 50-mg and 75-mg doses. T he bioavailability of low-dose oral etoposide was the same as that rep orted in previous higher dose oral etoposide bioavailability studies a nd that shown on the package insert supplied by the manufacturer. Impr oved bioavailability of low-dose oral etoposide was therefore not obse rved in a population of Japanese patients.