Bendamustine hydrochloride in patients with refractory soft tissue sarcoma

Abstract

For patients with advanced soft tissue sarcoma (STS), no standard treatment is established after previous chemotherapy with anthracyclines and ifosfamide. Bendamustine hydrochloride is a bifunctional alkylating agent that is not cross-resistant to other DNA-interacting substances including anthracyclines and oxazaphosphorines. It has shown single-agent activity in refractory lymphoma, myeloma, and some solid tumors. A phase 2 study was initiated to evaluate the efficacy of bendamustine in previously treated patients. Thirty-six of 44 screened patients were included and received a total of 101 cycles (median, 2 cycles; range, 1-8 cycles), 21 as second-line treatment and 15 as third-line treatment. The median age was 55 years (range, 18-79 years). Bendamustine was given as an intravenous infusion over 30 minutes at a dose of 100 mg/m(2) on 2 consecutive days and repeated every 28 days. Eighty-eight percent of cycles could be given without dose or schedule modification. The toxicity profile was mild, consisting of National Cancer Institute Common Toxicity Criteria (CTC) grade 3 neutropenia in 11% and grade 3 anemia in 9% of patients. Nonhematologic toxicities were noticed with CTC grade 3 fever in 3% of patients. No other grade 3 toxicity and no treatment-related toxic deaths were observed. The best overall response according to Response Evaluation Criteria in Solid Tumors (RECIST) criteria was 1 partial remission (3%) and disease stabilizations in 31% of patients. Six of 15 patients (40%) with leiomyosarcoma histology achieved stable disease. The estimated 3-month and 6-month progression-free survival rates were 35.3% and 23.5%, respectively, for all histologic subtypes included. In patients with refractory STS, bendamustine is well tolerated and appears moderately effective, particularly in patients with leiomyosarcoma histology.