Phase II trial of pegylated-liposomal doxorubicin (Doxil) in sarcoma

Pegylated-liposomal doxorubicin (Doxil) is a unique form of liposomal doxorubicin in which the liposomes are coated with methoxypoly (ethylene glycol), resulting in a diminished uptake by the reticuloendothelial system, leading to a longer half-life in blood and a different toxicity profile than nonpegylated liposomes. We performed a phase II study of Doxil in sarcoma. The patient population was primarily previously treated or had diagnoses considered unresponsive to chemotherapy. The initial dose per course was 55 mg/m2 every four weeks with dose modification based on mucositis and hand-foot syndrome (the main limiting toxicities). Treatment was generally well tolerated. Of 214 evaluable treatment courses in 47 patients, toxicities were mild and similar to previous reports, but dose reduction was common. No definite cardiac toxicity was observed. There were: 6 osteosarcomas, 3 Ewings, 1 extraosseous osteosarcoma, 1 chondrosarcoma, 2 alveolar soft part sarcomas, 15 gastrointestinal stromal cell tumors (GIST), and 19 other soft tissue sarcomas. Three of the 47 patients received a CR or PR, although 15 of the 47 patients were felt to have derived clinical benefit from the treatment. Some responses were delayed. These data suggest that pegylated-liposomal doxorubicin has activity in this population of poor prognosis sarcoma and that this treatment is associated with modest toxicity.