ACTIVITY OF STANDARD SOFT TISSUE SARCOMA-TYPE SYSTEMIC THERAPY IN CLEAR CELL SARCOMA (CCS): A RETROSPECTIVE INTERNATIONAL SERIES FROM THE WORLD SARCOMA NETWORK (WSN) (CTOS 2021)
Prospective trials of MET inhibitors, such as crizotinib and tivantinib, have increased our knowledge of this ultra-rare translocated sarcoma type, but there remains a huge unmet medical need...Thirty-four patients were treated with doxorubicin-based therapy, with a RECIST 1.1 response rate (RR) of 12% (n=4/34), mPFS of 3m (95% CI 0.9-4); thirteen received gemcitabine-based with RR 15% (n=2/13), mPFS 3m (95% CI 1.2-4.8); ten had sunitinib with RR 30% (n=3/10), mPFS 4m (95% CI 1.2-6.8-5.6). The response rate to the following treatments was 0%; dacarbazine (n=0/9, mPFS 2m 95%CI NA), pazopanib (n=0/16, mPFS 1m 95% CI 0-2.4), crizotinib (n=0/5, mPFS 2m 95%CI 0.9-3.1), checkpoint inhibitor (n=0/5, mPFS 2m 95%CI 0-5.9), trabectedin (n=0/7, mPFS 1m 95% CI 0-3.6), ifosfamide (n=0/5, mPFS 1 month 95% CI NA)... This is the largest retrospective study of systemic therapy in CCS. Systemic therapy has limited benefit in advanced CCS, with low RRs and short mPFS. Access to early clinical trial enrollment remains key for patients with CCS.