Purpose: We conducted a phase I/II trial of topotecan combined with gemcitabine in patients with metastatic or unresectable non-small cell lung cancer (NSCLC) based on preclinical data showing in vitro synergy against an established lung adenocarcinoma cell line. The aim was to determine the maximally tolerated dose (MTD) of topotecan when the gemcitabine dose is held constant, as well the dose limiting toxicity (DLTs) of this combination in NSCLC patients.
Patients and methods: Twenty-four patients with stage IIIB or IV NSCLC were treated weekly times 3 with a week break with gemcitabine (1250 mg/m2 over 30 minutes) and topotecan (30 minutes) at varying doses. The starting dose of topotecan was 1.0 mg/m2 and doses were escalated in 0.25-mg/m2 increments until the MTD was achieved.
Results: The MTD of gemcitabine/topotecan was 1250 mg/m2 of gemcitabine and 2.00 mg/m2 of topotecan (level 5). Neutropenia was the DLT. Few nonhematologic toxicities were observed. There were 5 (21%) partial responses among 24 patients. The median survival was 22 weeks. Two patients have had prolonged (> 2 year) survival.
Conclusion: The combination of gemcitabine and topotecan seems to be active against NSCLC with acceptable hematologic toxicity and minimal nonhematologic toxicity. The recommended dose for further study is 1250 mg/m2 of gemcitabine (days 1, 8, 15) and 2.0 mg/m2 of topotecan (days 1, 8, 15) administered every 28 days.