Canadian clinical trial underway to study colorectal cancer therapeutic vaccine

Toronto, ON — February 6, 2003 A clinical trial to evaluate the use of a therapeutic cancer vaccine in patients with Stage III colorectal cancer is now underway across Canada, according to study sponsor Aventis Pasteur. This trial complements another underway in the US and Canada, which is studying the vaccine in patients with more advanced disease.

Both studies are designed to determine how the investigational vaccine, ALVAC-CEA/B7.1, can be most effective when integrated with standard chemotherapy regimens to treat colon cancer. ALVAC-CEA/B7.1 is a cancer vaccine under development that uses a viral vector system derived from the canarypox virus. It is engineered to target the carcinoembryonic antigen (CEA), which is a protein that is over-expressed on the surface of the majority of colorectal cancer cells.

“We are committed to pursuing multiple routes to determine whether ALVAC-CEA/B7.1 has a role in improving overall outcomes when used with chemotherapy to treat colon cancer,” says Neil Berinstein, MD, assistant vice president clinical oncology, program director, cancer, with Aventis Pasteur.

The Canadian trial is enrolling patients with Stage III colorectal cancer at sites in Toronto, Ottawa, Vancouver, Edmonton, Calgary and Montreal.

Researchers engineered the ALVAC-CEA/B7.1 vaccine so that it produces a self-limiting, harmless infection, which causes infected cells to temporarily display the antigen CEA. CEA is found on the surface of about 95% of colorectal cancer cells. In response, the immune system becomes activated and attacks the tumor cells.

“While the ALVAC-CEA/B7.1 vaccine is designed to target one antigen involved in colorectal cancer, we also are studying the feasibility of a multi-antigen approach in future vaccine development,” notes Dr. Berinstein. “We also plan to explore whether vaccines should be used in combination with other anticancer agents like biologics or immunotherapy.”