Smart drug combats prostate cancer's helper proteins

Intravenously administered OGX-011 drug, inhibited the production of a gene protein called clusterin, which protects cancer cells.

The "chaperone" protein is targeted for suppression because of its helper role to cancer cells, allowing them to survive the assaults of treatments like chemotherapy and radiation by making tumours resistant to such therapy.

Conventional cancer treatments actually turn on the clusterin gene protein but by inhibiting it, OGX-011 helps boost the effectiveness of radiation, chemotherapy and other standard treatments after surgery.

In the Journal of the National Cancer Institute Wednesday, researchers from the B.C. Cancer Agency and the VGH Prostate Centre reported on the first human trial using OGX-011 in 25 patients.

The $1.4-million experiment was paid for by the U.S. Defence Department, which is sponsoring numerous prostate cancer trials to help thousands of aging war veterans diagnosed with the disease. The U.S. army has doled out hundreds of millions of dollars in grants for prostate cancer research since 1997.

Dr. Martin Gleave, the urologist who led the team that discovered and patented OGX-011, said that while clusterin is helpful in healthy people for its ability to help the body fight off certain stressors like cardiac events or other trauma, in those with cancer, it's nasty since it helps malignancies survive and spread.

Dr. Kim Chi, the BCCA oncologist who led the clinical trial, said the body's other defence mechanisms can step in when clusterin levels are reduced, as they were by about 90 per cent when patients were given the OGX-011 drug.

"Treatment for cancer in the past has involved poisons to kill the cancer cells. But in the next five years you'll be hearing a lot about these kinds of drugs which target cancer cells at the molecular level," Chi said.

Whether the drug actually helps patients live longer will be the subject of Phase 3 clinical trials.

Clusterin is also active in bladder, pancreas and kidney cancers, said Gleave, whose team was the first in the world to develop an anti-clusterin agent.

The OGX-011 drug is licensed to a University of B.C. biotechnology spinoff company.