Treatment of De-Differentiated Liposarcoma in the Era of Immunotherapy

Well-differentiated/de-differentiated liposarcoma (WDLPS/DDLPS) is one of the most common histologic subtypes of soft tissue sarcoma (STS); however, treatment options remain limited. WDLPS and DDLPS both exhibit the characteristic amplification of chromosome region 12q13-15, which contains the genes CDK4 and MDM2. DDLPS exhibits higher amplification ratios of these two and carries additional genomic lesions, including the amplification of chromosome region 1p32 and chromosome region 6q23, which may explain the more aggressive biology of DDLPS. WDLPS does not respond to systemic chemotherapy and is primarily managed with local therapy, including multiple resections and debulking procedures whenever clinically feasible. In contrast, DDLPS can respond to chemotherapy drugs and drug combinations, including doxorubicin (or doxorubicin in combination with ifosfamide), gemcitabine (or gemcitabine in combination with docetaxel), trabectedin, eribulin, and pazopanib. However, the response rate is generally low, and the response duration is usually short. This review highlights the clinical trials with developmental therapeutics that have been completed or are ongoing, including CDK4/6 inhibitors, MDM2 inhibitors, and immune checkpoint inhibitors. This review will also discuss the current landscape in assessing biomarkers for identifying tumors sensitive to immune checkpoint inhibitors.