LOS ANGELES (Reuters) - Arthritis drugs, such as Celebrex and the recently withdrawn Vioxx, may boost the immune system’s ability to attack brain tumors, and possibly other types of cancer, researchers reported on Friday.
Doctors at Cedars-Sinai Medical Center in Los Angeles have shown that the COX-2 enzyme is responsible for triggering a cellular process that disrupts the body’s immune response, allowing cancer cells to multiply.
COX-2 blockers -- a class that includes Pfizer Inc.'s Celebrex and Merck & Co Inc.'s late Vioxx -- treat arthritis pain by blocking the inflammation-causing COX-2 enzyme.
The results of the study, which appear in the October 1st issue of the Journal of Immunology, support the idea that drugs that block the COX-2 enzyme may also boost the immune system’s ability to recognize and target cancer cells.
“When secreted, COX-2 shuts down the immune system,” said Dr. John Yu, the study’s principal investigator. “We would hope to incorporate use of COX-2 inhibitors in all patients with brain tumors.”
Vioxx was withdrawn from the market last month after twice as many patients taking it for at least 18 months had MIs and strokes during a 2600-patient trial of the drug’s efficacy against precancerous colon polyps.
Merck also halted two other cancer-related studies of the drug -- one in men at risk of prostate cancer and another related to preventing colon cancer.
Using brain cancer cells, laboratory tests showed that COX-2 triggered a series of interactions that altered messages sent to dendritic cells. But circulating T-cells showed a regulatory response against the patient’s cancer cells, the study found.
“By using COX-2 inhibitors, these tumors may become more detectable and therefore more vulnerable to destruction by the immune system,” Dr. Yu said. Cedars-Sinai plans to add drugs like Celebrex to its clinical trials for brain tumors.
“Studies need to be done to see if there is relevance to other cancers,” Dr. Yu added.
MeSH Headings: Neoplasms : Diseases
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