Background:The burden of Alzheimer's disease and related dementia (ADRD) is projected to disproportionally impact low-middle-income countries (LMICs). However, there is a systematic under-representation of LMICs in ADRD clinical trial platforms.

BackgroundIn the absence of clinically meaningful disease‐modifying treatments, the number of adults with dementia worldwide is projected to more than triple. Much of this increase will occur in low and middle‐income countries (LMICs); by 2050, 68% of adults living with dementia will be in LMICs. However, there is a gross under‐representation of LMICs in historical and contemporary AD clinical trial platforms.MethodsWe aimed to determine the global distribution of dementia clinical trials and identify existing barriers for conducting AD clinical trials in LMICs. Our primary data sources to identify trial distribution in LMICs included ClinicalTrials.gov and World Health Organization International Clinical Trials Registry Platform. Data analysis included number of clinical trials per country, regional distribution, funding source, study phase (1, 1/2, 2, 2/3, or 3), and annual growth rate by region relative to population density. An additional systematic review search and expert consensus was conducted to identify barriers for conducting clinical trials in LMICs.ResultAmong 1737 dementia interventional trials, only 17.2% have been or are conducted in LMIC (figure 1). LMICs trial sites participated/conducted 23.6% and 10.9% of phase 3 and phase 1 trials, respectively. We identified several limitations for trial implementation including lack of financial resources, low industry presence, regulatory obstacles and operational barriers, especially related to resources in neuroimaging. Two successful international trials platforms (Dominantly Inherited Alzheimer Network‐Trials Unit [DIAN‐TU] and Worldwide FINGERS) have been able to expand into Latin American countries creating a regional network for trial implementation.ConclusionAlthough LMICs bear the greatest burden of AD in the world, substantial development of clinical trial platforms to address this inequity is lacking. Ongoing LMICs regional trial platforms (e.g., DIAN‐TU and LatAm‐FINGERS) may shed light on alternative strategies to overcome existing barriers and highlight the need for a more thoughtful approach to increase diverse representation in AD clinical trials and expand access to LMIC.