Phase I dose escalation study of pegylated liposomal doxorubicin (Caelyx®) in combination with topotecan in patients with advanced malignancies

Aims of this study were to determine the toxicity profile and the recommended dose of pegylated liposomal doxorubicin (Caelyx) in combination with topotecan in patients with advanced malignancies. Caelyx: 35 (DLI) or 40 (DLII) mg/m(2)/d1 was followed by 0.5 mg/m(2)/d topotecan daily for 5 days, every 4 weeks. Twenty-three patients received a total of 82 cycles. At DLII, 2/6 patients experienced dose-limiting toxicity consisting of grade 4 neutropenia lasting for more than 7 days and febrile neutropenia. At DLI, 4/18 and 2/18 patients presented febrile neutropenia and grade 4 sustained neutropenia, respectively. Non-hematological toxicities were mild to moderate. One patient with ovarian cancer presented a complete response. The hematological toxicity was a dose limiting factor that led to the recommended dose of 35 mg/m(2) Caelyx on day 1 with 0.5 mg/m(2)/d topotecan on days 1-5. This study results suggest that alternative schedules of this combination are required.