Recruitment and eligibility in a Phase 1 early Alzheimer's disease trial of Sabirnetug

Historically underrepresented racial and ethnic groups may face a higher risk and burden of dementia but continue to be underrepresented in Alzheimer's disease (AD) clinical research. Recent efforts have been insufficient to identify and address race-related disparities in recruitment and eligibility for AD clinical trials.

INTERCEPT-AD was a Phase 1 randomized, placebo-controlled, double-blind, first-in-human study of sabirnetug (ACU193) in participants with early symptomatic AD (mild cognitive impairment [MCI] or mild dementia due to AD). Participants were referred through seven site-selected recruitment strategies across 17 study sites in the United States (June 2021-January 2023). Numbers of pre-screened (n = 1025), screened (n = 260), and eligible (n = 70) participants were compared by recruitment strategy. Recruitment strategy effectiveness (percentage of eligible participants among screened participants) and reasons for screening ineligibility were compared between non-Hispanic White participants and participants from other racial and ethnic groups (i.e., participants who self-identified as American Indian or Alaska Native, Asian, Black or African American, or Hispanic or Latino).

Local site databases were used at 13 of 17 sites (76%) and accounted for the most screened (n = 107, 41%) and eligible (n = 32, 46%) participants. Non-Hispanic White participants were recruited from all seven recruitment strategies, whereas participants of other racial and ethnic groups were recruited primarily from site databases. Significantly more participants of other racial and ethnic groups were ineligible for the study after screening, largely due to ineligible amyloid positron emission tomography (PET) scans (+13.9%).

Diverse recruitment tactics, customized to capabilities of study sites and patient populations, may be more successful in recruiting diverse populations than a one-size-fits-all approach. Although a diverse pool of potential participants was screened, a less diverse group was enrolled, largely due to race- and ethnicity-related disparities in screening eligibility rates. Further investigation is needed to assess equitable screening methods for AD clinical trials.

Site databases recruited the most screened and enrolled participants.Diverse participants were primarily recruited from site databases.The diversity of enrolled participants was lower than screened participants.More ineligible participants were from diverse racial and ethnic groups.No approach was observed to be a one-size-fits-all method to recruit and enroll a diverse pool of participants.