The findings appear in the April 1 issue JAMA Dermatology. This study is the first meta-analysis of the quality of safety reporting in clinical trials of finasteride for treatment of male hair loss.
Not one of the 34 published clinical trial reports provided adequate information about the severity, frequency, or reversibility of sexual adverse effects. Adequate quality of adverse event reporting requires using an explicit toxicity scale to grade adverse event severity and reported numbers and/or rates of occurrence for each specific type of adverse event per study arm, the study authors point out.
Of 5,704 men in a clinical data repository from Northwestern University in Chicago who were treated for male pattern baldness with finasteride, only 31% would meet inclusion criteria for the pivotal trials referenced in the manufacturer’s “Full Prescribing Information.”
Thus, the available information from clinical trials does not apply to most of these men in Northwestern’s study population who took finasteride for male pattern baldness. For example, some men with hair loss who are taking finasteride have diabetes mellitus, high blood pressure, or are taking other drugs such as diuretics or antidepressants that also increase the risk of sexual dysfunction.
Duration of drug safety evaluation was limited to 1 year or less for 26 of 34 trials (76%). But 33% of men in the clinical data repository took finasteride for more than 1 year.
The published clinical trial reports did not answer the key questions doctors and patients want to know:
1) How safe is finasteride? Specifically, what is the risk that a man taking finasteride will develop sexual dysfunction?
2) How severe is finasteride-associated sexual dysfunction when it happens to a man?
3) If a man gets sexual dysfunction while taking finasteride, will sexual function return to normal when the drug is stopped? What is the risk of persistent sexual dysfunction associated with taking finasteride?
“People who take or prescribe the drug assume it’s safe, but there is insufficient information to make that judgment,” says lead study author Dr Steven Belknap, research assistant professor of dermatology and general internal medicine at Northwestern University Feinberg School of Medicine in Chicago, in a news release. “Our findings raise several questions,” Belknap says. “Why do the published reports of these 34 clinical trials not provide adequate information about the severity and frequency of sexual toxicity? Was this information obtained but then not included in published articles? Or, were these clinical trials performed in a way that simply didn’t capture this essential information? And most importantly, is the risk to benefit ratio of finasteride acceptable?”
The study is a report from the Research on Adverse Drug Events and Reports (RADAR) project at Northwestern’s Feinberg School. The RADAR study points to a larger problem in the way clinical trials are performed and analyzed in meta-analyses. “Typically, there is more focus on the desirable effects of the drug being studied compared to the toxic effects,” Belknap adds.