Purpose: This study was a phase I/II, cohort, dose-escalation trial of topotecan and paclitaxel. Its aim was to determine the dose-limiting toxicity (DLT) of the combination and to define the maximum tolerated dose (MTD), as a recommended dose for phase II, as well as to get preliminary data on the efficacy (activity) of the drug in pretreated patients with ovarian cancer, small-cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC).
Methods: Included in the study were 52 pretreated patients, 19 with ovarian cancer, 20 with SCLC and 13 with NSCLC. The doses of topotecan were escalated from 1.25 to 2 mg/m2 and of paclitaxel from 60 to 80 mg/m2. A minimum of four patients were included at each of the six levels of dose escalation.
Results: We found that DLT due to grade 3 and 4 myelotoxicity was at levels 5 and 6 at doses of 1.75 and 80 mg/m2 (level 5) and 2 and 80 mg/m2 (level 6) for topotecan and paclitaxel, respectively. The MTD and recommended accepted doses are 1.75 mg/m2 for topotecan and 70 mg/m2 for paclitaxel. Of the 52 patients, 17 (33%) showed a response: 1 complete response (1.92%) and 16 partial responses (30.77%).
Conclusions: Topotecan combined with paclitaxel administered once weekly for three consecutive weeks repeated for every 28 days resulted in well-tolerated toxicity at doses of 1.75 and 70 mg/m2, respectively, and a response rate of 33% in pretreated cancer patients.