Researchers discover therapy for treating terminal stages of cancer

Oct 5 2010

For the first time ever, researchers have discovered a therapy that can effectively treat the now invariably lethal, terminal stages of cancer in animals. The study appears in the latest issue of the Proceedings of the National Academy of Sciences.

"Our research shows that a novel monoclonal antibody can help block the now terminal stage of cancer," says Robert Debs, MD, researcher/scientist with the California Pacific Medical Center Research Institute in San Francisco, and one of the lead authors of the study. "So far it has shown effectiveness in mice against colon and breast cancers and melanoma. Furthermore, it does not produce any obvious toxic effects, even when given to mice already suffering from highly advanced cancers. Rather, it helps to treat the progressive weight loss associated with advanced cancers."

Currently, the end stages of metastatic cancer - the highly advanced cancers that have already spread to other parts of the body from its original location - are untreatable. Most patients die from this phase of the cancer because of its progressively debilitating, organ-destroying qualities. Part of the problem with finding a treatment was the lack of understanding of the molecular mechanisms governing the lethal growth of these already large and destructive cancers. Up to now, the terminal stages of cancer have been considered hopeless. Therefore, they are not studied, and new anti-cancer approaches are not tested against them. The present study shows that the moratorium on studying terminal cancers, as well as developing treatments effective against them should now end.

The results show that advanced cancers are fueled by the platelet endothelial cell adhesion-1 (PECAM-1) molecule, which regulates the levels of circulating proteins that promote cancer growth. By creating a monoclonal antibody that specifically blocks PECAM-1, the researchers have found a treatment that effectively treats the terminal-stages of cancer.

"The anti-PECAM-1 antibody is very exciting because it shows effectiveness against a number of terminal cancers, and also concurrently slows the debilitating wasting syndrome that can develop as cancerous tumors become large, disseminated and destructive," says Debs.

The anti-PECAM-1 antibody produces its anti-tumor effects by binding to a protein on the surface of cells that line normal blood vessels, instead of binding to tumor cells. The protein to which the antibody binds appears to control the secretion of critical growth factors, which regulate the growth of advanced tumor metastases.

"Identifying these growth-promoting factors represents an important advance," says Dr. Michael Rowbotham, Director of the California Pacific Medical Research Institute. "It would provide us with additional anti-cancer targets which may significantly increase our ability to stop the fatal growth of terminal cancers."

While this current round of research was done in mice, the researchers say they hope to be able to begin testing this approach in people within 24 months.

"This is the first step," says Debs, "but it has the potential to significantly improve the lives of patients now suffering hopelessly from terminal cancers."

Four of the researchers involved in the study have financial links to Genomic Systems LLC, which provided partial funding for the researcher. However, the study design and findings were independently audited to ensure no conflict of interest and the final paper was edited by a researcher not connected to the project.