Vinorelbine in previously treated advanced childhood sarcomas: Evidence of activity in rhadbomyosarcoma

BACKGROUND. Vinca alkaloids have proved active against a number of pediatric malignancies. The aim of this study was to assess the feasibility and effectiveness of using vinorelbine in previously treated pediatric patients with advanced sarcomas. METHODS. From September 1998 to August 2001, 33 previously treated patients with progressive sarcoma were treated: 13 had rhabdomyosarcomas, 5 had other soft tissue sarcomas, 9 had Ewing sarcomas, and 6 had osteosarcomas. Vinorelbine was given intravenously on Days 1 and 8 of a 21-day treatment cycle. Four patients with uncontrolled pain or central nervous system invasion received concurrent radiotherapy and were only evaluated for toxicity. RESULTS. One hundred seventy-eight treatment cycles were administered (median of four per patient, range 1-20). Grade 3 to 4 neutropenia occurred in 63% of patients, Grade 3 anemia in 9%, and Grade 3 thrombocytopenia in 3%. Nonhematological toxicity was mild or moderate, i.e., always lower than Grade 3, with the exception of one child who experienced paralytic ileus. Twenty-eight patients were assessable for response. Eight patients had a partial response, one patient had a minor response, and nine patients had stable disease. Objective responses were observed in 6 of 12 patients with rhadbomyosarcomas (five of six of the alveolar subtype), in one of five patients with osteosarcomas, and in one of seven patients with Ewing sarcomas. The median duration of response was 10 months (range, 3+ to 20). CONCLUSIONS. Vinorelbine has a favorable toxicity profile with evidence of biological activity in already heavily treated pediatric patients with sarcomas. In particular, the objective response rate obtained for patients with alveolar rhabdomyosarcoma seems very promising. Due to the few cases considered here, further Phase II studies are needed to establish a potential role of vinorelbine in the treatment of these tumors.