A bitter pill to swallow – how medical studies exclude(d) women

When I followed the recent media coverage of AstraZeneca and read about the way the vaccine has more adverse effects in women than men, I couldn’t help but think about an issue that still hasn’t been resolved yet. Once again, it has become evident: when it comes to pharmaceutical products, your biological sex makes a difference. Something scientists have known since the 1950s, and which should be self-evident by now. Yet, it wasn’t until 2014 that the European Union passed a new clinical trial regulation (No 536/2014) stating that trials should primarily represent the gender, age or ethnic group that was most likely to use the medicinal product. To mark the occasion of the International Day of Action for Women’s Health on the 28th of May, I’d like to share with you a little more about the subject.

According to the “Verband forschender Arzneimittelhersteller” (Association of Research-Based Pharmaceutical Companies), Phase I of clinical trials still only includes between 10 and 40 percent female participants. Meaning that the majority of participants are male. Due to their body structure, men need a higher dosage for a drug to show any effect. In addition, the male hormone system is completely different from that of women, so if men don’t experience side effects, it doesn’t necessarily mean that women won’t. If those conducting clinical trials don’t take into account the physical differences between the sexes, it can do serious harm to women.

Why the lack of gender diversity in clinical trials is dangerous

A popular example is the sleeping pill Zolpidem. At first women were prescribed the same dosage as men, which led to an increased number of car accidents in areas where the drug was sold. This mysterious trend was eventually linked to women who had taken the pill the night before. What nobody knew then is that female patients should have taken half of the prescribed dosage, because the drug affected them longer and more intensively than it did men.

What may sound anecdotal happens more often than it should. It made me think of the case of Digoxin in 2002. The medication against heart failure had been exclusively tested on men. Not only did it not produce the desired effect in women, it actually led to premature death in some cases. Postmenopausal hormones and the active ingredients in Digoxin clashed within the body, ironically leading to heart failure. Since men don’t go through menopause, this side effect obviously didn’t manifest during trials.

Reasons why there hasn’t been more gender diversity in clinical trials to date

I guess the main reason for this situation might simply be the following: it’s more complicated to conduct clinical trials on women than to conduct them on men. The male body and its functions remain more or less the same throughout their lives. The female body, on the other hand, is constantly changing – every month, due to the menstrual cycle, and on a larger scale, such as pregnancy or menopause.

Another aspect is the ability to compare. Since most studies in the past have been conducted on men, new study results show a higher comparability if the trials are also conducted on male participants.

The next reason may be what I’d like to call unconscious ignorance: it’s still the case that the majority of researchers, chemical developers, doctors and members of supervisory boards are men. They may merely lack the insight to consider the impact their decisions have on women. Simply put, they could be ignorant without meaning to be.

And last but not least: finding clinical trial participants is fairly cost-intensive to begin with, and for the reasons I mentioned above, men have lower drop-out rates. Therefore, the goal of finding a balance between male and female participants is often shifted to simply finding any participants at all, while keeping the costs for the trial at a minimum.

Why it’s time for more gender diversity in clinical trials

Low costs, however, can’t be a valid excuse. Those conducting clinical trials have to ensure that they find the right balance between male and female participants. Firstly, because it’s simply the right thing to do! Women make up half of the world’s population, so their needs should be considered just as much as men’s. Secondly, because more diverse trials could yield new insights and new solutions in medicine, which in the end would be beneficial for everyone, regardless of their sex.

Photo by Danilo Alvesd on Unsplash

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