Background: Treatment options for patients with unresectable and/or metastatic dedifferentiated liposarcoma (DDLPS) are limited. The most effective agents include doxorubicin, ifosfamide, trabectedin and eribulin, but, in general, objective response rates (ORR) and progression free survival (PFS) are modest. Cabazitaxel exerts its effect through inhibition of microtubular disassembly and has been shown to be relatively safe, effective and well-tolerated. EORTC 1202 assessed whether cabazitaxel demonstrated sufficient antitumor activity in patients with metastatic or inoperable locally advanced DD LPS to justify further investigation in a phase III setting. Methods: This was an international multi-center, open label single arm phase II trial. The clinical cut-off date for the primary analysis was performed on August 31, 2020. Data base lock was performed on February 2, 2021. Eligible patients with metastatic or inoperable locally advanced DD LPS, after a centralized pathological review, were treated with cabazitaxel 25mg/m² IV infusion over 1 hour every 21 days. Primary endpoint was PFS rate at 12 weeks assessed by local investigator per RECIST 1.1. Based on a Simon two-stage design, at least 4 out of 17 (Stage 1) and 11 out of 37 (Stage 2) eligible and evaluable patients who are progression-free at 12 weeks were needed. Currently, a centralized radiological assessment is ongoing. Results: Forty patients were registered by 10 institutions in 4 countries between March 2015 and March 2019, with 2 patients being ineligible. One patient was still on treatment at the clinical cut-off date. The number of cycles ranged from 1 to 30, with a median of 5; 26 patients (65%) received at least 4 cycles of cabazitaxel. PFS at 12 weeks was 55% (conditional 1-sided 95% CI 40.8-100), achieving the primary study endpoint. The median FU was 21.6 months, median PFS was 6 months and median OS 21 months. RR was 8% with one CR and two PR. Twenty-three(60.5%) pts had a SD. Disease control (PR+SD) was achieved in 26 patients (68%). The most common cabazitaxel -related grade >3 adverse events in all 40 registered patients were Neutrophil count decreased (50%), febrile neutropenia (25%), fatigue (12.5%), and anemia (10%). There were no cabazitaxel-related deaths. Conclusions: EORTC 1202 met its primary endpoint, with 21/38 pts (55%) being progression-free at 12 weeks. Results of this trial confirm activity of cabazitaxel in patients with metastatic or inoperable locally advanced DD LPS and looks interesting if compared to the other available options and experimental drugs recently reported in this patient population. Clinical trial information: NCT01913652