Phase I study of non-pegylated liposomal doxorubicin in combination with ifosfamide in adult patients with metastatic soft tissue sarcomas.

Objective: The aim of this study was to evaluate the maximum tolerated dose (MTD) and safety of the combination of non- pegylated liposomal doxorubicin (Myocet) and ifosfamide in patients with metastatic soft tissue sarcomas.

Methods: Cohorts of four patients with metastatic soft tissue sarcomas received up to five cycles of intravenous ifosfamide 3000 mg/m2 on days 1- 3 in combination with escalating doses of intravenous Myocet on day 1 every 3 weeks until dose limiting toxicity (DLT) in at least one patient. Starting dose of Myocet was 40 mg/m2 to be escalated through 10 mg/m2 increase up to 80 mg/m2. Toxicity was graded according to the National Cancer Institute Common Toxicity Criteria v3.0 (NCI-CTC v3.0).

Results: Ten patients were enrolled in the study and 8 of them received the treatment. Median age was 45 years, 3 patients were male and 5 were female. DLT, consisting of neutropenic fever, was reached in one patient at dose level 2 (Myocet 50 mg/m2). Therefore, the MTD and the recommended phase II dose is 40 mg/m2.

Conclusions: The combination of intravenous Myocet 40 mg/m2 on day 1 and ifosfamide 3,000 mg/m2 on days 1-3 every 3 weeks is safe and feasible; a phase II study is ongoing.