A Phase II multicenter, open-label, clinical and pharmokinetic trial of PM00104 in patients with advanced Ewing Family of Tumors

Ewing sarcoma is a rare connective tissue tumor characterized by the translocation of the EWS gene, mainly between chromosome 11 and 22, giving rise to gene re-arrangements between the EWS gene and various members of the ETS gene family. Multi-agent chemotherapy has improved the outcome for patients with localized Ewing sarcoma, but survival of patients with recurrent/metastatic disease remains poor. An exploratory two-stage, single-arm Phase II multicenter trial of the synthetic alkaloid, PM00104, was conducted in patients with recurrent Ewing sarcoma. The primary end point of the trial was objective response rate. PM00104 was administered at a dose of 2 mg/m(2) on Days 1, 8 and 15 of a 4 week cycle. Seventeen patients were recruited. No objective responses were reported in the 16 patients evaluable for efficacy. Recruitment was closed without proceeding to the second stage of the trial. Four patients achieved stable disease as best response, and in two of these patients the stabilization was longer than 4 months. The median progression-free survival was 1.8 months (95 % CI, 0.9-3.5 months) and median overall survival was not reached (95%CI, 56.2 % at censored data). Pharmacokinetics in patients with Ewing sarcoma was similar to that previously reported in other patient populations. PM00104 showed modest activity in Ewing sarcoma at 2 mg/m(2) on a weekly schedule. There remains an unmet need for effective therapies for patients with advanced/metastatic Ewing sarcoma.