Clinical trials expanded with novel vaccine.

2003 MAR 12 - (NewsRx.com & NewsRx.net) -- Several additional cancer centers in the United States and Canada are enrolling patients in a clinical trial evaluating the use of a therapeutic cancer vaccine in patients with first-line metastatic colorectal cancer. In addition, a second trial using the vaccine earlier in the course of disease is now under way in centers across Canada, according to Aventis Pasteur, Ltd of Toronto, the study sponsor.

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 unique 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 overexpressed 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," said Neil Berinstein, MD, assistant vice president clinical oncology, program director, cancer, Aventis Pasteur. "By adding more trial locations for our first study, and initiating the second study, we are demonstrating our confidence in moving the ALVAC vaccine forward."

New clinical trial sites for patients with metastatic colon cancer have been established in the following cities: Chicago (two sites); Tampa, Florida; Portland, Oregon; and Dunmore, Pennsylvania; Toronto, Ottawa, and Montreal. Other sites have been enrolling patients in New York City; Washington, DC; Philadelphia; Los Angeles; and Birmingham, Alabama.

Trial sites enrolling patients with earlier stage colorectal cancer are in Toronto (two sites); Ottawa; Vancouver; Edmonton; Calgary; and Montreal.

Unfortunately, cancer cells are largely tolerated rather than destroyed by the body's immune system. But special proteins or antigens, found predominantly in cancer cells, can serve as potential targets for the immune system to attack. In developing vaccines for cancer, the challenge is to find targets that are only found on the cancer cell and to use these targets to effectively reawaken the immune system to overcome its so-called tolerance to cancer, and to launch an attack on the targeted cancer cells.

Researchers engineered the ALVAC-CEA/B7.1 vaccine so that for a short period of time, 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.