South Korean firm SillaJen has started patient enrolment in a Phase I/II clinical trial of its clinical candidate pexastimogene devacirepvec (Pexa-Vec) combined with checkpoint inhibitors to treat metastatic colon cancer.
Based on the firm’s Selective Oncolytic Vaccinia Engineering (SOLVE) platform, Pexa-Vec is designed to delete the thymidine kinase (TK) gene in cancer cells to target their common genetic defects.
The product candidate is also engineered to express GM-CSF protein that complements cancer cell lysis, which results in tumour necrosis and vasculature shutdown along with the sustained anti-tumoural immune attack.
The trial is being sponsored and led by the National Cancer Institute (NCI), a division of the US's National Institutes of Health (NIH) in the US under a cooperative research and development agreement (CRADA).
Under the agreement, Dr Tim Greten from the NCI will enrol and treat subjects, while SillaJen will be responsible for the supply of Pexa-Vec.
The agreement provides SillaJen with access to NCI's scientific and clinical expertise for development of the product candidate.
SillaJen chief medical officer James Burke said: “Cancer immunotherapy is significantly impacting multiple cancer types, and we hope this trial will provide further understanding about how our immunotherapy might help patients with CRC, particularly given the limited treatment options available to this patient population.”
The trial will investigate the combination of Pexa-Vec with an anti-PDL1 antibody durvalumab, as well as with both durvalumab and anti-CTLA4 antibody tremelimumab in participants suffering from refractory metastatic colorectal cancer (CRC).
Through the trial, SillaJen aims to determine if combining an oncolytic virus with immune checkpoint inhibitor therapy could trigger the immune system against cancer and to overcome self-tolerance.