Phase II clinical trial of neoadjuvant trabectedin in patients with advanced localized myxoid liposarcoma

Background: To evaluate neoadjuvant trabectedin (1.5 mg/m. ² 24-h i.v. infusion every 3 weeks; three to six cycles) in patients with locally advanced myoxid liposarcoma (ML) previously untreated with chemotherapy or radiation. Patients and methods: Primary efficacy end point was pathological complete response (pCR) or tumoral regression rate. Objective response according to RECIST (v.1.0) was a secondary end point. Results: Three of 23 assessable patients had pCR [13%; 95% confidence interval (CI), 3% to 34%]. Furthermore, very good and moderate histological responses were observed in another 2 and 10 patients, respectively. Histological decrement in the cellular and vascular tumor component and maturation of tumor cells to lipoblasts were observed in both myoxid and myoxid/round cell variants. Seven patients had partial response according to RECIST (objective response rate of 24%; 95% CI, 10% to 44%). No disease progression was reported. Neoadjuvant trabectedin was usually well tolerated, with a safety profile similar to that described in patients with soft tissue sarcoma or other tumor types. Conclusion: Trabectedin 1.5 mg/m. ² given as a 24-h i.v. infusion every 3 weeks is a therapeutic option in the neoadjuvant setting of ML.