A Phase II Trial of Carboplatin and Weekly Topotecan in the First-Line Treatment of Patients with Extensive Stage Small Cell Lung Cancer

Background: Carboplatin and topotecan are commonly used in the treatment of small cell lung cancer (SCLC); however, there are no data for this combination in the first-line setting using weekly topotecan. In this multicenter, community-based phase II trial, we evaluated carboplatin and weekly topotecan in the previously untreated patients with extensive stage SCLC. Methods: This trial was designed to achieve an objective response rate (ORR) of 70% (alpha = 0.05; beta = 0.20); secondary aims were to assess time to progression, toxicity, and overall survival (OS). Patients with Eastern Cooperative Oncology Group performance status 0 to 1, measurable disease, and adequate organ function were eligible. Treatment: carboplatin area under the concentration-time curve = 5 (intravenous) on day 1 and topotecan 4 mg/m(2) (intravenous) on days 1 and 8, every 21 days for up to six cycles, with restaging every 6 weeks (per RECIST). Results: Between June 2006 and November 2008, 61 patients were enrolled. The median follow-up is 40 weeks (range 27-109 weeks). Patient characteristics were as follows: median age 67 years (range 40-84 years); male, 53%; and Eastern Cooperative Oncology Group performance status 0, 28%. Complete responses were seen in two patients and partial responses in 33 patients; ORR was 57% (95% confidence interval [CI]44 -70). Stable disease was seen in 12 patients (20%), and progressive disease was seen in two patients (3%). The median time to progression was 5.5 months (95% CI 4.0-6.3 months). The median OS was 8.5 months (95% CI 7.2-11.4 months). One-year OS was 29%. Grade 3/4 toxicity in >5%: neutropenia (66%), thrombocytopenia (48%), leukopenia (40%), anemia (30%), fatigue (13%), dehydration (8%), infection (8%), and pain (7%). Conclusions: The ORR achieved with carboplatin and weekly topotecan was less than the anticipated rate of 70%; however, it was comparable with historical rates seen with other platinum doublets in the first-line extensive stage SCLC setting. This regimen was generally well tolerated, with myelosuppression as its primary toxicity.