SillaJen, Inc. announced the initiation of a Phase 1/2 clinical trial of pexastimogene devacirepvec (Pexa-Vec) in combination with checkpoint inhibitor therapy for the treatment of metastatic colon cancer. The study, led by Dr. Tim Greten at the National Cancer Institute (NCI), is being conducted as part of a Cooperative Research and Development Agreement (CRADA) with the NCI, part of the National Institutes of Health (NIH). Under the CRADA, SillaJen will collaborate with Dr. Greten to evaluate the combination of SillaJen's lead clinical candidate, Pexa-Vec in combination with durvalumab (anti-PDL1 antibody) and, in a separate treatment group, with both durvalumab and tremelimumab (anti-CTLA4 antibody) in patients with refractory metastatic CRC. The aim of the trial will be to test if the combination of oncolytic virus and immune checkpoint inhibitor therapy can activate the immune system to fight cancer and overcome self-tolerance to colon cancer. Further, in depth assessment of tumor biopsies, and other collected patient samples, will be conducted to assess the immune modulating potential of Pexa-Vec given concurrently with checkpoint inhibitor therapy.