Efficacy of Pembrolizumab in Multiple Subtypes of Sarcoma

Lisa H. Butterfield, PhD, professor of medicine, surgery, and immunology, director, University of Pittsburgh Immunologic Monitoring and Cellular Products Laboratory, University of Pittsburgh, president of the Society for Immunotherapy of Cancer, discusses a clinical trial exploring the PD-1 inhibitor pembrolizumab (Keytruda) in multiple subtypes of sarcoma.

This is one of the first tests of PD-1 blockade in sarcomas because the tumors are very divergent, Butterfield explains. The study shows that there was efficacy in 3 subtypes of sarcoma, which leads to the next level of questioning: what are the biomarkers? In a tumor analysis, PD-L1 staining was found on some tumor, There were also interesting findings of PD-L1 expression levels on tumors that was unexpectedly low, given the clinical outcomes. This will not be an easy "story" to tell, she adds.

By examining serum, it was found that soluble PD ligands being correlative of good clinical outcomes and a new area to pursue further.