Drugs that fall into the category of 5-alpha reductase inhibitors (5 ARIs), such as Avodart (dutasteride) and Proscar (finasteride) have recently been in the news. These drugs have previously been approved to treat the symptoms of prostate enlargement by causing the prostate to shrink in size. Propecia, which is a 1 mg dose of finasteride is also used to treat male pattern balding. This category of drugs has been proven to be extremely effective in treating patients with symptoms of outlet obstruction.
Glaxo Smith Kline (GSK), the manufacturer of dutasteride, submitted a supplemental file to the FDA for an additional indication of the drug for reducing the risk of the development of prostate cancer. In December, the FDA voted that the risks outweigh the benefits of both of the drugs in this category and that neither drug should be used to prevent prostate cancer. The basis for this discussion was the slight increased incidence of men developing high grade prostate cancer (Gleason socres 8-10) while utilizing these medications.
Two studies helped support this decision. A study conducted by GSK, the Reduction by Dutasteride of Prosate Cancer Events (REDUCE) study, demonstrated an increased incidence of high grade prostate cancer (Gleason score 8-10) compared to men who were taking a placebo (1% vs .5%). 29 high grade cancers were identified in men taking the drug versus 19 men who developed high grade disease in the placebo group. An additional study conducted by Merck, the Prostate Cancer Prevention Trial (PCPT), a 26% overall decrease in all prostate cancer was identified, however this study too demonstrated a slightly increased (1.3%) incidence of the high grade cancers. It should be noted, however, that both drugs demonstrated a statistically significant reduction in the incidence of prostate cancer (4 years for dutasteride and 7 years for finasteride), implying that there may be some chemopreventive effect for these agents.
The American Urological Association (AUA) on July 25th, has recommended the use of the 2008 clinical guidelines that have previously been published that states “Asymptomatic men with a prostate-specific antigen (PSA) 3.0 ng/mL who are regularly screened with PSA or are anticipating undergoing annual PSA screening for early detection of prostate cancer may benefit from a discussion of both the benefits of 5-ARIs for seven years for the prevention of prostate cancer and the potential risks (including the possibility of high-grade prostate cancer)”.
This clearly will not be the end of the discussion about the merits and potential drawbacks to utilizing these medications. Both drugs are efficacious with regards to the treatment of BPH and that indication is not being questioned by the FDA. The AUA has expressed concern regarding the recent FDA warning and is scheduled to meet with them later this summer. Presently, the best recommendation is that if you are using these medications, please discuss the rationale behind the use of these drugs at the time of your next office visit with your Urologist.
Published On: August 15, 2011