Viruses and bacteria can be reprogrammed to help eliminate cancer.
In addition to modified tumor cells, bacteria and viruses can also be equipped with pro-immune / anti-cancer abilities. Several different virus-based strategies exist, the most successful being T-VEC, an oncolytic virus immunotherapy that’s already FDA-approved for melanoma (more on this tomorrow).
Another approach–CRS-207—uses de-fanged but living bacteria (L. monocytogenes) to vaccinate patients.
CRS-207 cells are changed in two important ways. First, they have been “double-deleted” which renders them less dangerous to normal cells. Second, they have been loaded with the recipe for a specific protein—mesothelin—that’s expressed by several types of cancers. This vaccination is designed to provide the immune system with the information necessary to mount a tumor-specific response.
The therapeutic benefits of CRS-207 in combination with other immunotherapies, including GVAX and checkpoint inhibitors, are currently being evaluated in clinical trials for patients with gastro-esophageal cancer, ovarian cancer, pancreatic cancer, and mesothelioma.
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