Phase II study of ecteinascidin-743 in advanced pretreated soft tissue sarcoma patients

A multicenter phase II study evaluating efficacy, safety, and pharmacokinetics of ecteinascidin-743 (ET-743) in pretreated advanced soft tissue sarcoma patients.

Patients received ET-743 1,500 microg/m(2) (24-hour intravenous infusion) every 3 weeks (group 1, 26 patients with one to two prior single agents or one previous combination chemotherapy; group 2, 28 patients with three or more prior single agents or two or more previous combination chemotherapies). Results Patients (30 women, 24 men) had a median age of 48 years (range, 22 to 71 years); 41% had leiomyosarcoma (eight of 22 of uterine origin), a median of two involved organs (range, one to four), and 93% had documented progressive disease at study entry. Patients received a median of three cycles (range, one to 20); 28% received six or more cycles. Fifty-two patients were assessable for response (WHO criteria): two partial responses, four minor responses, and nine with stable disease (> or = 6 months). Three patients were rendered tumor free after surgery. Median progression-free survival was 1.9 months (range, 0.69 to 17.90 months); 24% of patients were progression free at 6 months. Median survival was 12.8 months, with 30% of patients alive at 2 years. Four patients withdrew because of treatment-related toxicity. Two treatment-related deaths occurred (renal failure and febrile neutropenia, and rhabdomyolysis and decompensated cirrhosis, respectively) that were probably related to protocol eligibility violations. Reversible grade 3 to 4 AST or ALT occurred in 50% of patients and grade 3 to 4 neutropenia occurred in 61% of patients, with six episodes of febrile neutropenia. Nausea, vomiting, and asthenia were prevalent but mild and manageable.

With a 4% overall response rate (95% CI, 0.5 to 12.8) and an 11% rate of third-party-verified tumor regression (overall response rate + minor response), ET-743 has a 24% 6-month disease progression control rate, confirming evidence of antitumoral activity and a manageable safety profile in patients experiencing disease progression with pretreated soft tissue sarcoma.