According to health officials, this Thursday, a class of drugs meant to improve symptoms of an enlarged prostate gland may actually increase the chance of getting a more serious form of prostate cancer. However they also said the drugs' benefits outweigh the risks.
The report suggests that drugs in this group include Merck & Co's Proscar and GlaxoSmithKline's Avodar and Jalyn, as well as Merck's Propecia, which is approved to treat male pattern hair loss.
The Food and Drug Administration said it revised the labels on all such drugs, called 5-alpha reductase inhibitors (5-ARI), to include the risk after reviewing two large studies. 5-ARI drugs are known clinically as finasteride and dutasteride and are used to treat benign prostatic hyperplasia (BPH), or prostate enlargement, a common condition in men over 40. Propecia, for male baldness, includes a smaller dose of finasteride.
The results of these studies were the focus of a meeting of the FDA’s Oncologic Drugs Advisory Committee in December 2010. The said studies found that daily use of 5-ARIs for several years decreased the chance of getting lower-risk forms of prostate cancer but made it more likely that patients would get a high-grade prostate cancer, which grows and spreads more quickly.
The Prostate Cancer Prevention Trial (PCPT) evaluated daily use of finasteride 5 mg versus placebo for 7 years, and the Reduction by Dutasteride of Prostate Cancer Events (REDUCE) trial evaluated daily use of dutasteride 0.5 mg versus placebo for 4 years. In those two studies, the risk of being diagnosed with prostate cancer was significantly reduced among those randomized to either of the two drugs, compared with those on placebo. But the reduction was because of a lower rate of lower-grade prostate cancers (with a Gleason score of 6 or lower). The risk of higher grade prostate cancers (with a Gleason score of 8-10) was increased among those who received one of the two 5-ARIs.
The FDA said on its website, “This risk appears to be low, but healthcare professionals should be aware of this safety information, and weigh the known benefits against the potential risks when deciding to start or continue treatment with 5-ARIs in men.” Before prescribing one of these drugs, the statement advises that health care professionals “perform appropriate evaluation to rule out other urological conditions, including prostate cancer, [which] might mimic” benign prostatic hyperplasia (BPH).
The FDA said about 5 million male patients were given a prescription for a 5-ARI from 2002 to 2009. The drugs' benefits in treating BPH still outweighed any risks, it said. Another class of medicines known as alpha-blockers can also be used to treat symptoms of BPH. Drugs of this type include Astellas Pharma's Flomax, Pfizer Inc's Cardura, and Rapaflo from Watson Pharmaceuticals.