The influence of gender, age, and race on the pharmacokinetics of etoposide and on the extent of conversion of etoposide phosphate (Etopophos; Bristol-Myers Squibb Company, Princeton, NJ) to etoposide are summarized. Included in the integrated statistical analyses were 192 patients from six phase I/II studies (102 men and 90 women, 128 aged < or = 65 years and 64 aged > 65 years; 134 were white, 18 were other races, and race was not recorded for 40). The dose of etoposide phosphate ranged from 25 to 200 mg/m2 of etoposide equivalents and was administered as 5-(bolus) to 210-minute intravenous infusions. Total body clearance of etoposide was comparable between men and women. However, significantly lower steady-state volumes of distribution and shorter half-lives were observed in women relative to men. Patients who were older than 65 years had significantly lower etoposide total body clearance and longer half-lives than younger patients. The gender- and age-related differences observed in the pharmacokinetic parameters of etoposide were significant but generally of a small magnitude (< or = 13%), indicating no need for dose adjustment in these patient populations. There were no significant race-related differences in the pharmacokinetic parameters of etoposide. All patients showed rapid conversion of etoposide phosphate to etoposide. The individual area under the plasma concentration-time curve ratio of etoposide phosphate/etoposide was < or = 0.0324, indicating that etoposide was the major circulating moiety after infusion of etoposide phosphate. Significant gender-, age-, or race-related differences in the area under the plasma concentration-time curve ratios were not observed. An evaluation of the area under the plasma concentration-time curve ratios with respect to infusion time suggested that the conversion of etoposide phosphate to etoposide was independent of infusion time.