Phase I combination study of trabectedin and doxorubicin in patients with soft-tissue sarcoma

To determine the dose of trabectedin plus doxorubicin with granulocyte colony-stimulating factor support associated with manageable neutropenia and acceptable dose-limiting toxicities (DLT) in patients with recurrent or persistent soft-tissue sarcoma.

In this phase I, open-label, multicenter trial, patients previously treated with 0-1 prior chemotherapy regimens excluding doxorubicin, an Eastern Cooperative Oncology Group performance status 0-1, and adequate organ function received a 10- to 15-min i.v. infusion of doxorubicin 60 mg/m(2) immediately followed by a 3-h i.v. infusion of trabectedin 0.9 to 1.3 mg/m(2) on day 1 of a 3-week cycle. Because four of the first six patients experienced DLT-defining neutropenia during cycle 1, all subsequent patients received primary prophylactic granulocyte colony-stimulating factor. The maximum tolerated dose was the highest dose level with six or more patients in which less than one-third of the patients experienced severe neutropenia or DLT. Blood was collected during cycle 1 for pharmacokinetic analyses. Adverse events, tumor response, and survival were assessed.

Patients (N = 41) received a median of six cycles of treatment (range, 2-13). The maximum tolerated dose was trabectedin 1.1 mg/m(2) and doxorubicin 60 mg/m(2). Common grade 3/4 treatment-emergent adverse events were neutropenia (71%), alanine aminotransferase increase (46%), and thrombocytopenia (37%). Overall, 5 (12%) patients achieved a partial response and 34 (83%) maintained stable disease. Median progression-free survival was 9.2 months. Doxorubicin and trabectedin pharmacokinetics were not altered substantially with concomitant administration.

The combination of doxorubicin 60 mg/m(2) followed by trabectedin 1.1 mg/m(2) every 21 days is safe and active in patients with soft-tissue sarcoma.