Feasibility of oral topotecan in previously untreated patients with small-cell lung cancer ineligible for standard therapy

Abstract

The single-agent activity of intravenous (i.v.) topotecan has been established in small-cell lung cancer (SCLC), with overall tumor responses of 39% in previously untreated patients and 11-37% in relapsed patients. An oral formulation of topotecan has been developed that is more convenient for patients, which may lead to greater compliance and greater prescribing flexibility for use in combination with other active agents. We initiated a phase II trial to test the feasibility of oral topotecan administered at 2.0 mg/m(2) on days 1-5 of a 21-day cycle in previously untreated SCLC patients. Patients received a median of 5 courses of oral topotecan. Grade 3/4 myelosuppression was common in patients treated with 2.0 mg/m(2); secondary to 2 patients developing fatal sepsis, patients enrolled later in the study were treated at 1.7 mg/m(2). At both doses, the majority of nonhematologic toxicity was grade 1/2 in severity, and there were no discontinuations attributed to nonhematologic toxicity. In a patient population reflective of the general SCLC population (i.e. elderly with multiple comorbidities), oral topotecan was generally well tolerated at the lower dose level, with a preliminary antitumor activity profile comparable to i.v. topotecan. Clinical studies are currently under way to compare the antitumor activity of oral topotecan with i.v. topotecan in second-line SCLC and investigate oral topotecan in combination with other active agents in SCLC.