Lack of diversity in clinical trials
The lack of diversity among participants in clinical trials is a longstanding problem. Black and Hispanic people are up to twice as likely as white individuals to develop Alzheimer’s disease, but they have a significantly lower chance of being included in clinical trials for Alzheimer’s treatments. Only 20% of approved participants in 2023 trials for the Alzheimer’s drug lecanemab were people of color ①, and 8.5 % in the trial for donanemab ②.
This lack of representation in clinical trials is concerning because it means that the effectiveness and potential side effects of Alzheimer’s treatments may not be accurately understood for these communities. The underrepresentation of people of color in clinical trials reflects the wider disparities in healthcare access and opportunities that exist in these communities. For clinical trials, this includes considering factors such as race, ethnicity, gender, age, and socioeconomic background when recruiting participants and analyzing results.
There are several reasons why people of color may be underrepresented in clinical trials. Firstly, there may be a lack of awareness and information about ongoing trials within these communities. Secondly, there might be cultural and language barriers that prevent individuals from participating. Additionally, historical experiences of exploitation and mistreatment in medical research, such as the Tuskegee Syphilis Study, have created mistrust and skepticism within minority communities.
To address this issue, it is crucial to actively involve and engage diverse communities in clinical trials. Researchers and pharmaceutical companies should make concerted efforts to recruit a more representative sample of participants. This can be done through community outreach programs, partnering with trusted community leaders and organizations, and providing culturally sensitive information about the trials.
Moreover, it is important that healthcare providers and researchers prioritize diversity and inclusion in clinical trial design and implementation. There are several factors to be mindful of during the process of qualifying people of color for clinical trials. They face higher rates of disorders that disqualify them from trials, including cardiovascular disease and lupus. In Alzheimer-related clinical trials that screen for both amyloid and tau, a significantly lower number of non-white participants qualified than did their white counterparts. Why is that? One factor is that people of color have a higher prevalence rate of other conditions (e.g., vascular disorders, inflammation, etc.) that cause dementia. Another consideration is that genetic variations can influence an individual’s risk for developing Alzheimer’s disease and other forms of cognitive impairment. Certain genetic variants are more common in specific racial or ethnic groups, and these variants may be associated with differences in amyloid and tau levels ③ ④.
We must simply do better to address diversity in clinical trial research. To ensure that clinical trials are truly representative of the population as a whole, it is also important to include a diverse group of researchers and healthcare providers in the trial process. This can help to ensure that the perspectives and needs of individuals from diverse backgrounds are taken into account.
① van Dyck, C.H., et al. (2023). Lecanemab in Early Alzheimer’s Disease. N Engl J Med. 388(1):9-21. doi: 10.1056/NEJMoa2212948.
② Sims, J.R.: The TRAILBLAZER-ALZ 2 Randomized Clinical Trial. JAMA. 330(6):512–527. doi:10.1001/jama.2023.13239et al. (2023). Donanemab in Early Symptomatic Alzheimer Disease
③ Le Guen, Y., et al. (2023). Association of African Ancestry-Specific APOE Missense Variant R145C With Risk of Alzheimer Disease. JAMA. 329(7):551-560. doi: 10.1001/jama.2023.0268.
④ Naslavsky, M.S., et al. (2023). Global and local ancestry modulate APOE association with Alzheimer’s neuropathology and cognitive outcomes in an admixed sample. Mol Psychiatry. 27(11):4800-4808. doi: 10.1038/s41380-022-01729-x.