A phase 2 trial of trabectedin in children with recurrent rhabdomyosarcoma, Ewing sarcoma and non-rhabdomyosarcoma soft tissue sarcomas: A report from the Children’s Oncology Group

PurposeTo determine the toxicity, efficacy and pharmacokinetics of trabectedin given over 24 h every 3 weeks to children with recurrent rhabdomyosarcoma, Ewing sarcoma, or non-rhabdomyosarcoma soft tissue sarcomas.Patients and methodsTrabectedin was administered as a 24-h intravenous infusion every 21 days. Two dose levels were evaluated (1.3 and 1.5 mg/m2) for safety; efficacy was then evaluated using a traditional 2-stage design (10 + 10) at the 1.5 mg/m2 dose level. Pharmacokinetics (day 1 and steady state) were performed during cycle 1.ResultsFifty patients were enroled, eight patients at 1.3 mg/m2 and 42 at 1.5 mg/m2. Dose limiting toxicities (DLTs) in the dose finding component included fatigue and reversible GGT elevation in 1/6 evaluable patients at 1.3 mg/m2 and 0/5 at 1.5 mg/m2. Efficacy was evaluated in 42 patients enroled at the 1.5 mg/m2 dose of whom 22% experienced reversible grade 3 or 4 toxicities that included AST, ALT, or GGT elevations, myelosuppression and deep venous thrombosis.One patient with rhabdomyosarcoma had a partial response and one patient each with rhabdomyosarcoma, spindle cell sarcoma and Ewing sarcoma had stable disease for 2, 3 and 15 cycles, respectively.ConclusionTrabectedin is safe when administered over 24 h at 1.5 mg/m2. Trabectedin did not demonstrate sufficient activity as a single agent for children with relapsed paediatric sarcomas.