Study of PDS0101 and Pembrolizumab Combination I/O in Subjects With HPV16 + Recurrent and/or Metastatic HNSCC

PDS0101 is a novel T-cell HPV-specific immunotherapy delivered subcutaneously that has been shown to stimulate high levels of HPV16-specific CD8+ and CD4+ T cells within patients by activating multiple immune pathways. These HPV-specific T cells then target tumors such as head and neck, anal and cervical cancers that are caused by HPV infection. The number of HNSCC cases has been increasing steadily over the last 10-15 years and over 90% of HPV-positive head and neck cancers are HPV16 positive. Pembrolizumab has been shown to have efficacy against both HPV-positive and HPV-negative head and neck cancers. However, its effectiveness is more optimal in tumors that are PD-L1 positive and have evidence of immune cells within the tumor. We hypothesize that increasing tumor-targeting HPV-specific T-cells with PDS0101 will be associated with an increased response to pembrolizumab. This study will explore in a preliminary manner whether combination treatment with PDS0101 plus pembrolizumab will improve clinical efficacy over that seen with pembrolizumab alone in the KEYNOTE-048 study. Subjects will be enrolled into either the checkpoint inhibitor (CPI) naïve cohort or the CPI refractory cohort.