Phase II Study of Topotecan and Etoposide as Second-line Treatment in Chemotherapy-refractory Small-cell Lung Cancer

Refractory small-cell lung cancer (SCLC) has a poor prognosis, and current salvage chemotherapy for refractory SCLC, such as CAV (cyclophosphamide, adriamycin, vincristine) or topotecan, has an unsatisfactory outcome, with a response rate and overall survival of less than 10% and 6 months, respectively. This phase II study evaluated the role of topotecan combined with etoposide in SCLC patients that have progressed, or relapsed, within 3 months following completion of the initial chemotherapy.

Twenty-seven patients were entered into this study. Eligible patients had an ECOG performance status of less than, or equal to, 2, at least one bidimensionally measurable lesion and adequate end organ function. IV topotecan, 1.0 mg/m2/d for 5 consecutive days, and etoposide, 100 mg/m2/d through days 1 to 3, were administered every 3 weeks until disease progression or undue toxicity.

The major toxicity was myelosuppression. Grade 3/4 anemia, granulocytopenia, and thrombocy-topenia occurred in 14.2, 34.8, and 27.3% of cycles, respectively. There was no treatment-related death, and other non-hematologic toxicities were generally mild. Four patients achieved partial responses, with a response rate RR of 14.8%. The progression-free survival PFS ranged from 1 to 7 months, with a median of 2.0 months (95% confidence interval 1.22~2.78 months). Twenty-five patients died, with a median overall survival of 5.5 months (ranging from 1 to 21 months, 95% CI 4.32~6.68 months), and the 6-month survival rate was 32.1% (95% confidence interval 14.4~49.8%).

The combination of topotecan and etoposide chemotherapy showed a modest response rate, but failed to prolong survival of refractory SCLC patients compared to topotecan monotherapy.