Majority of top-selling and most promoted drugs in Canada are rated as having very limited safety and efficacy

A new study, published in CMAJ Open, investigated the claim, often made by pharmaceutical companies, that drug promotion is primarily conducted to inform and educate physicians. Dr. Joel Lexchin’s examination found that many of the top-selling and most-promoted drugs in Canada had little to no therapeutic value.

“Examining whether the medicines that are heavily promoted are the ones that provide the most therapeutic gain may help in determining whether doctors should be using promotional material to inform themselves about therapeutically important drugs.”

The knowledge that drug promotion tactics influence physician prescribing behaviors is “generally accepted,” writes Lexchin. While pharmaceutical companies explain the aim of drug promotion as a means of informing and educating practitioners, many express concerns that the influence of drug promotion may be more harmful than beneficial.

A recent study, conducted in the U.S. found that the top 25 most heavily promoted drugs in 2015 had low therapeutic value, meaning these drugs were deemed to have low effectiveness, safety, novelty, and affordability. In this study, Lexchin researched the drugs that are most heavily promoted in Canada, as well as the therapeutic value of those drugs.

The objective of the study was to observe whether drug promotion is being used to inform physicians of therapeutically important drugs. Annual reports from QuintilesIMS, a company that publicly and consistently reports the amount of money spent on journal advertisements, the number of visits by drug sales representatives, and the top drugs by sales revenue, were used to gather data on drug promotion.

Lexchin recorded the names of the top 50 drugs promoted in 2013, 2014, and 2015. He excluded drugs that were featured twice (generic and brand names) and instruments used for measuring blood glucose level. In order to determine the therapeutic gain from products, Lexchin referred to two different sources, the Patented Medicine Prices Review Board (PMPRB) and the independent French drug bulletin, Prescrir International.

“I chose these sources because they both provide objective assessments of therapeutic value that do not require any subjective interpretation,” he explains.

Although both sources have slightly different assessment criteria and processes, both primarily assessed drugs on the basis of efficacy and safety. Based on these reviews, the drugs were sorted into three main categories, (1) major therapeutic gain, (2) moderate therapeutic gain, and (3) little to no therapeutic gain. It is important to note, however, that therapeutic information was only available for 53% of the most-promoted drugs and 66% of the top-selling drugs.

Findings demonstrated that 90-96% of the most-promoted drugs were rated as having little to no therapeutic gain. The same was true for 77-79% of the top-selling drugs. The difference in the drugs’ therapeutic value between the top-selling and most-promoted drugs was only significant in the year 2013.

“The finding that there was a difference in therapeutic distribution between the most-promoted drugs and the top-selling drugs in only 1 of the 3 years studied may mean that there are few therapeutically significant products that can be promoted,” writes Lexchin.

Although, he adds that perhaps drugs with high therapeutic value sell without the need to promote them, or are promoted through other methods. Numbers detailing promotional expenditures in 2013 indicate that 96.5% of expenses went toward drugs rated as having little to no therapeutic gain. No proportion of expenditures were devoted to drugs rated as having major therapeutic gain. In 2014, 92% of money spent went toward promoting drugs with little to no therapeutic gain, followed by 93.8% in 2015.

Results of this study find that most promotion and advertising efforts were centered around promoting drugs with little to no therapeutic value, and that the majority of top-selling drugs reflected this pattern as well.

Another study examined promotion through meetings, talks, direct-to-consumer advertising, booths at medical conferences, and more, and found that minimally adequate safety information about drugs was provided in less than 2% of promotions that took place both in Vancouver and Montreal. Given the number of studies in Canada and the U.S. with results highlighting concerning patterns of drug promotion, the issue may be widespread.

“Innovative Medicines Canada, the organization representing the research-based companies, says on its website that its mandate is to provide ‘access to education and information about the appropriate uses of our products and services’ to doctors. The findings of the current study and that by Mintzes and colleagues about sales representatives raise questions about whether this mandate is being fulfilled.”

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Lexchin, J. (2017). The relation between promotional spending on drugs and their therapeutic gain: a cohort analysis. CMAJ Open, 5(3), E724. doi: 10.9778/cmajo.20170089 (Link)