Gender Gap in Clinical Trials has been observed by few studies conducted lately. More so, there have been studies that have completely excluded women, or acutely underrepresented them. One study, ‘The Physicians Health Study’ was carried out to examine how taking low-dose aspirin might lower your risk for heart disease. The study, that ended in 1989 had zero women and 22,000 men as participants. Studies in biomedical research that adopt a one-size-fits-all approach may not have accurate results for the female population as their bodies react differently to drugs. 

On a molecular and cellular level, the two sexes: men and women have biological distinctions that can lead to different outcomes in clinical trials. Differences can exist in disease prevalence, diagnosis, the severity of health outcomes. Some diseases may inordinately affect women and yet, sex-specific differences haven’t been addressed or analyzed in data collected during drug trials in the past few decades.  

How The Gender Gap in Clinical Trials has Widened

The widespread opinion that data from male participants could also be applied to women is one of the primary reasons that women were excluded from clinical research. Hormonal changes in women were also considered as impediments and scientists took the easier path: that of using males wholly or mostly in clinical trials. One trial for a drug called thalidomide that included women in the 1950s and 60s gave rise to birth defects and that led to FDA guidelines that recommended leaving out women with childbearing potential in early phases of clinical trials. The guidelines were wrongly applied to all research phases and led to the under-representation of women in most trials. Some scientists exclude women from trials, as they believe the fluctuation in hormones during menstrual cycles can complicate the research process or make it more expensive. 

Interestingly, women aren’t the only ones to be excluded from the studies, as trials tend to primarily use Caucasian males. Black men are also less likely to be included in clinical trials for cancer, although they are twice as likely to die from prostate cancer than Caucasian men. In 1992, an FDA-led discussion about women in clinical trials established the importance of including women in clinical trials to understand how they react to certain drugs. In 1993, the US Congress passed the National Institutes of Health Revitalization Act that expressly stated that women and people of colour have to be included in any clinical research funded by the government. Research funded by pharmaceutical companies doesn’t come under this act. The study fell behind on setting real standards concerning the inclusion of women and minorities in clinical research. 

Lack Of Clinical Data Can Lead to Health Risks in Women

In July 2019, a study looking at women’s participation in medical research for the past 25 years(1993 to 2018) was published. The study by Allen Institute for Artificial Intelligence, Seattle combed through almost 43,000 research studies in PubMed, a searchable database of biomedical science, and 13,000 clinical trials registered on for gender-biased studies. Although on the whole women comprised 49 percent of participants across studies, researchers found them mostly underrepresented when the studies were broken down based on disease types and conditions. Women were largely underrepresented when it came to conditions like chronic kidney disease, gynecologic cancer, digestive disease, hepatitis, HIV, and cardiovascular disease.  According to an FDA article, in trials supporting 36 cardiovascular approvals, of 224,417 participants, only 34 percent were women. This points to a serious gap in research that results in a lack of understanding of the effectiveness of drugs and their safety when used by women. 

Some disease states affect women more than men, be it breast cancer, urinary incontinence, and lung cancer. They also show up differently in women, like cardiovascular diseases where women have different symptoms as compared to men. Sexually transmitted diseases also have different effects on women be it in symptoms, susceptibility, and long-term complications. Women may respond differently to treatment owing to variation in the physiology of the two sexes. Research that includes women can determine the clinical relevance of these differences and contribute to the development of safe and effective drugs for both men and women. As per Global Participation in Clinical Trials Report by the FDA in 2017, women represent 43 percent of clinical trials globally while men represent 57 percent. The female: male ratio in trial participants globally was found to be between 30:70 and 45:55 proving that women are still largely underrepresented in trials.  

Women have also been found to have problems during pregnancy when they consume over-the-counter drugs, as these medicines haven’t been tested on pregnant women. In April 2018, the FDA took a step towards addressing the disparity by releasing guidelines on how to include pregnant women in drug development clinical trials for drugs and biological products. Some ways to address the skewed male: female ratio includes using the right diagnostic tests for women and including female animals in preclinical trials. A review that assessed almost 2,300 trials on animals found that more than 80 percent of the animals were male. This alarming statistic shows that there is much work that needs to be done in bridging the gender gap in clinical trials. Pharmaceutical companies, government bodies as well as researchers and scientists must put in substantial efforts to include women in clinical trials to provide them with safe and effective drugs.