Do Merck, Glaxo Prostate Drugs Raise Cancer Risk? Maybe Not
Merck & Co. and GlaxoSmithKline Plc (GSK)’s drugs for hair loss and enlarged prostate will carry new U.S. warnings about a low risk of being diagnosed with a more serious form of prostate cancer.
The Food and Drug Administration revised the prescribing information for Merck’s Proscar and Propecia and Glaxo’s Avodart and Jalyn based on the findings of two studies, the agency said today in a statement. From 2002 to 2009 about 5 million men were prescribed one of these drugs, known as 5-ARIs, including almost 3 million men ages 50 to 79, the FDA said.
This surprised me, and I asked Otis Brawley, chief medical officer of the American Cancer Society and a prostate cancer doctor himself, what he thought. Brawley wrote back:
I and most docs who have reviewed the data believe that these drugs cause small high grade tumors that already exist to be more easily diagnosed by shrinking the normal prostate and not the cancer within it. It is does not cause high grade cancer in my opinion. There are a small number of people who think these drugs might cause high grade cancer. I seriously do not see evidence for that.
Update: Merck added this comment, which I’ve edited.
Merck stands behind the demonstrated safety and efficacy of PROSCAR (finasteride, 5mg) and PROPECIA (finasteride, 1mg), for benign prostatic hyperplasia (BPH or enlarged prostate) and male pattern hair loss since, respectively.
Merck has been working with the FDA to update the PROSCAR labeling based on findings from the Prostate Cancer Prevention Trial (PCPT), an independent trial conducted by the Southwest Oncology Group.
The PCPT trial showed that treatment with PROSCAR significantly reduced the risk of prostate cancer overall compared to placebo. The trial also showed a slight, but significant, proportion of high-grade (more serious) cancer among some men treated with PROSCAR. PROPECIA was not included in the trial. Patients should talk with their doctor before they stop taking any of their medicines.
The ISHRS (International Society of Hair Restoration Surgery) invited a keynote speaker (expert urologist) a few years back to the Annual Scientific Meeting when the prostate research was initially published. His opinion was the same as the CMO, Otis Brawley / American Cancer Society... shrinking normal tissue made the smaller, more rare aggressive prostate cancer easier to find on biopsy and this resulted in the increase in the reported findings in the clinical trial. Keep in mind that the same studies showed that mild to moderate prostate cancers decrased by up to 30% in patients on Proscar. --Dr. Alan Bauman