New analysis boosts drug's prostate cancer value
By Will Dunham
WASHINGTON (Reuters) - A new analysis of data from a key prostate cancer study has strengthened the view that a drug that is now sold as a generic may be a valuable weapon to prevent prostate cancer, researchers said on Monday.
The drug is finasteride, formerly sold by Merck and Co as Proscar to treat enlargement of the prostate and now available generically. The drug affects male hormone levels.
The men in the study were taking the drug in a dose of 5 milligrams. In a one milligram dose, finasteride is sold by Merck as the baldness remedy Propecia.
The initial results of the study were announced in 2003.
The extensive reanalysis of the data showed that finasteride reduced a man's risk for developing prostate cancer by about 30 percent, the researchers said. That compares to the initial finding that it reduces the risk by about 25 percent.
When the initial results of the study were announced, the researchers cautioned that men in the study who developed prostate cancer while taking finasteride were more likely to have high-grade cancers, which may spread quickly even if the tumors are small.
But the new analysis showed finasteride did not induce aggressive cancers and may reduce the risk of these high-grade tumors, said Dr. Ian Thompson of the University of Texas Health Sciences Center at San Antonio, who led the original study and was involved in reassessing the data.
The researchers also concluded the cancer cases finasteride prevented in the trial were "clinically significant" in that they were the same type that currently are treated with radiation and surgical removal of the prostate gland.
Many men in the United States and some other countries use the prostate-specific antigen, or PSA, blood test to screen for prostate cancer. PSA is a substance produced by the prostate gland that in a high level may indicate prostate cancer.
"Conceivably, every man when he turns 55, if prostate cancer is of concern to him -- if he's having the PSA checked on a regular basis -- his doctor probably should at least tell him that he can reduce his risk by about 30 percent by taking finasteride," Thompson said in a telephone interview.
The new analyses were released at a meeting of the American Urological Association in Orlando and published in the journal Cancer Prevention Research.
The study involved 18,882 men age 55 and up who did not have prostate cancer when the research began. One group was given finasteride and the rest given a placebo for seven years to see whether the drug prevented the disease.
"About 200,000 men per year are detected with prostate cancer in the United States. And of those men, in excess of 90 percent are treated with radiation or surgery, which have some side effects. About a third to a quarter of those men might never have been diagnosed with prostate cancer had they been taking finasteride. That's a big deal," Thompson said.
Finasteride is currently used to treat a noncancerous enlargement of the prostate that causes urine flow problems.
"I wish I had known then what I know now because it would have been a home run when it was first published, and when the drug was not generic. Unfortunately, now the drug is generic, so there's nobody to actually take the drug to the FDA (U.S. Food and Drug Administration for approval for prostate cancer prevention)," Thompson said.