CRS-207 is an immunotherapy developed by Aduro Biotech of Berkeley, California. It belongs to a family of products based on Aduro’s LADD platform, which uses Listeria bacteria to activate strong immune responses against specific tumor-associated antigens (TAAs). An antigen is a substance that is not normally present in the body and that can trigger an immune response.

The treatment is currently being tested in mesothelioma patients, and those with gastric and ovarian cancer.

How CRS-207 works

The LADD platform (live, attenuated double-deleted Listeria) is based on proprietary attenuated strains of Listeria monocytogenes engineered to express TAAs and induce specific and targeted immune responses. Genes that might harm patients are deleted from the bacteria’s genome, allowing it to be given safely without compromising its therapeutic benefit.

CRS-207 is likely to stimulate an immune response to mesothelin, a TAAs that is overproduced by some tumors, including mesothelioma as well as pancreatic, ovarian, gastric and lung cancers. Mesothelin, which also helps spread cancer cells, is found only in limited amounts in normal tissues.

CRS-207 in clinical trials

CRS-207 is being evaluated in several clinical trials along with other treatments in people with different cancer types.

A Phase 2 study (NCT03175172) now recruiting 35 U.S. patients is assessing the safety and efficacy of CRS-207 along with Keytruda (pembrolizumab) in adults with malignant pleural mesothelioma who have failed prior anti-cancer therapy. It aims to measure the number of participants with a complete or partial response, time from the first dose of treatment until disease progression or death, and improvement in lung function. The study should be completed by March 2019.

Another Phase 2 trial (NCT03122548) is recruiting 79 U.S. participants with recurrent or metastatic gastric, gastroesophageal or esophageal cancers to assess the safety and efficacy of the same combination. It is expected to end by May 2019.

A two-part Phase 1/2 study (NCT02575807) will test CRS-207, epacadostat and Keytruda in 126 women with platinum-resistant ovarian, fallopian tube or peritoneal cancer. The trial will investigate whether different combinations of the three treatments can slow the growth of cancer and help these women live longer. The trial seeks U.S. and Canadian participants and should be done by December 2018.

Two Phase 2 studies (NCT03190265 and NCT03006302) are expected to begin soon to evaluate the safety and clinical activity of CRS-207 combined with other anticancer treatments in people with pancreatic cancer.


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