GSE202361
Neoadjuvant immune checkpoint blockade in retroperitoneal dedifferentiated liposarcoma and extremity/trunk undifferentiated pleomorphic sarcoma (NCT03307616)
Recent evidence suggests that immune checkpoint blockade (ICB) has some activity in metastatic dedifferentiated liposarcoma (DDLPS) and undifferentiated pleomorphic sarcoma (UPS). We conducted a randomized, non-comparative phase 2 trial (NCT03307616) of nivolumab or nivolumab/ipilimumab in patients with resectable retroperitoneal DDLPS (n=17) and extremity/truncal UPS (n=10), with UPS patients receiving concurrent radiation therapy. The primary endpoint of pathologic response as assessed by percent hyalinization was observed to be a median of 8.8% in DDLPS patients and 89% in UPS patients and similar in nivolumab and ipilimumab/nivolumab arms in both cohorts . Higher intratumoral densities of T-regulatory cells were associated with absence of pathologic response (hyalinization<30%). Tumor infiltration by B-cells was associated with higher densities of T-regulatory cells before treatment;  this association was lost upon ICB treatment. Our data demonstrate that neoadjuvant ICB with concurrent radiation may have significant efficacy in UPS and is associated complex immune changes in the tumor microenvironment in DDLPS and UPS. Overall design: Tumor samples were collected at baseline, on treatment and at surgery for all patients, and analyzed using bulk RNA sequencing.