Dendritic-Cell Vaccine Shows Durable Control in 20% of Metastatic Sarcoma, Tied to T-Cell–Rich Tumor Microenvironment

In a Phase I trial (NCT01803152), 19 patients with advanced or metastatic sarcoma received an autologous dendritic-cell vaccine after prior therapies; median PFS was 9.5 months, with 4 (21%) long-term responders (>2 y PFS): two patients with pleomorphic myxofibrosarcoma, one with leiomyosarcoma and one pediatric patient with Ewing sarcoma. Imaging-mass-cytometry of archival tumors found responders (n = 4) harbored ~12-fold more CD8⁺ T cells, ~8-fold more CD4⁺ T cells, and doubled M1/M2 macrophage densities versus non-responders. No new safety issues were reported.