Phase I study of weekly paclitaxel and liposomal doxorubicin in patients with advanced solid tumours

The aim of this study was to determine the maximum tolerated dose (MTD) and the dose-limiting toxicities (DLT) of a weekly administration of paclitaxel and pegylated liposomal doxorubicin (Caelyx; Schering Plough Pharmaceutical) in patients with advanced solid tumours. 19 pretreated patients with solid tumours received escalated doses of pegylated liposomal doxorubicin (6-12 mg/m(2)) as a 1-h intravenous (i.v.) infusion followed by a fixed dose of paclitaxel (80 mg/m(2)) weekly for 4 consecutive weeks in cycles of 6 weeks. DLT was defined as grade 4 neutropenia or thrombocytopenia, febrile neutropenia, grades 3 or 4 non-haematological toxicity or treatment delay due to unresolved toxicity during cycle 1. The MTD was reached at the dose of pegylated liposomal doxorubicin of 10 mg/m(2)/week and paclitaxel of 80 mg/m(2)/week. The DLTs were treatment delay due to grade 3 neutropenia and grade 3 diarrhoea. A total of 55 chemotherapy cycles were administered, and grades 3-4 neutropenia occurred in seven cycles (13%); the non-haematological toxicity was mild with grades 2/3 diarrhoea occurring in 4 (7%), grades 2-4 asthenia in 11 (20%) and grade 2 mucositis in 7 (13%) cycles. There was no case with more than a 10% LVEF decrease after a median of 3 (range 2-6) administered cycles/patients. One patient with breast cancer and 1 with ovarian cancer experienced a major partial response. The weekly administration of pegylated liposomal doxorubicin at the dose of 10 mg/m(2) in combination with paclitaxel at the dose of 80 mg/m(2) for 4 consecutive weeks, in cycles of 6 weeks which represent the recommended doses for further phase II studies, is a well tolerated regimen, which merits further evaluation in tumours known to be sensitive to taxanes and/or anthracyclines.