Efficacy and Safety of Oral Topotecan and Bevacizumab Combination As Second-line Treatment for Relapsed Small-cell Lung Cancer: an Open-label Multicenter Single-arm Phase II Study

Background: Topotecan is currently the only US Federal Drug Administration (FDA)-approved drug for second-line treatment of relapsed small-cell lung cancer (SCLC). We investigated the efficacy and safety of a novel topotecan-bevacizumab combination in treating relapsed SCLC.

Patients And Methods: Each 21-day treatment cycle consisted of bevacizumab (15 mg/kg) administration on day 1 and oral topotecan (2.3 mg/m(2)/d) administration on days 1 to 5. Treatment was continued for 8 cycles or until disease progression/toxicity. The primary objective was evaluation of 3-month progression-free survival (PFS). Overall response rate (ORR), duration of response, time to response (TTR), and overall survival (OS) were secondary objectives.

Results: The study enrolled 50 patients between July 2008 and May 2010. The 3-month PFS was 65% (95% confidence interval [CI], 49.3%-76.9%), which was promising compared with the historical control of 50% (P = .017) but did not meet the predefined criteria for clinically meaningful improvement. Median PFS was 6.24 months for the sensitive subgroup (progression time from end of previous chemotherapy > 90 days; n = 27) and 2.91 months for the resistant subgroup (progression time ≤ 90 days; n = 23). No patient achieved complete response (CR), and the ORR was 16%. Twenty (40%) patients had stable disease (SD) and 13 (26%) had progressive disease (PD). Median OS, TTR, and duration of response were 7.4, 1.3, and 4.7 months, respectively. The worst reported adverse events (AEs) were grade 1/2 in 11 (22%) patients and grade 3/4/5 in 39 (78%) patients.

Conclusion: Improvement in the 3-month PFS after treatment with topotecan-bevacizumab was promising compared with the historical control and justifies additional studies with this regimen.