Randomized Phase II Study of Maintenance Irinotecan Therapy Versus Observation Following Induction Chemotherapy with Irinotecan and Cisplatin in Extensive Disease Small Cell Lung Cancer

IntroductionTo determine whether irinotecan maintenance therapy in extensive disease-small cell lung cancer can improve survival of patients who responded to irinotecan plus cisplatin (IP) induction therapy.MethodsA total of 120 chemo-naive patients with adequate organ functions and Eastern Cooperative Oncology Group performance status of 0 to 2 were enrolled from March 2003 through April 2006. After IP induction therapy, with either schedule A (I: 60 mg/m2 intravenously (IV) on days 1, 8, and 15; P: 30 mg/m2 IV on days 1 and 8, every 4 weeks for six cycles) or schedule B (I: 60 mg/m2 and P: 30 mg/m2 IV on days 1, and 8, every 3 weeks for eight cycles), responding patients were randomized to either maintenance with irinotecan 100 mg/m2 IV on days 1, 8, and 15, every 4 weeks up to six cycles, or observation.ResultsOverall, 100 (83%) of 120 patients achieved objective tumor responses (12 complete responses, 88 partial responses) after IP induction therapy. Of those patients who remained in remission upon completion of planned cycles of induction therapy, 45 were randomized to maintenance (n = 21) or observation (n = 24). Median progression-free survival (PFS) and overall survival (OS) for all patients were 7.2 and 14.0 months, respectively. For the maintenance arm, median PFS and OS were 12.0 and 17.6 months, respectively. For the observation arm, median PFS and OS were 9.9 and 20.5 months, respectively, which was not significantly different from the maintenance arm.ConclusionsIP chemotherapy is very useful for the treatment of small cell lung cancer. However, maintenance irinotecan therapy did not seem to further affect the clinical outcome of patients who had responded to IP induction therapy.