Participation in U.S.-Based ALS Clinical Trials by Sex and Race

In global amyotrophic lateral sclerosis (ALS) trials, women and men appear to be proportionately enrolled, but quantification of enrollment by sex and race in U.S.-based ALS trials is limited. The objective of this study was to evaluate the sex and race of participants enrolled in U.S.-based ALS clinical trials.

Participant demographics were extracted from recent U.S.-based Phase 2 and 3 ALS trials identified in literature and on ClinicalTrials.gov. The Centers for Disease Control and Prevention (CDC) National ALS Registry and a 2014 State Surveillance Project were used as proxies for prevalence. Participation-to-prevalence (PPR) ratios were calculated for sex and race. A modified time-trend analysis was performed for race for participants enrolled before and after 2020.

A total of 11 trials met criteria for inclusion with a total of 1153 patients enrolled. Compared to the CDC Registry, the PPR was 0.76 (95% CI: 0.63-0.90) for women, 1.26 (95% CI: 1.23-1.29) for White participants, 0.34 (95% CI: 0.17-0.51) for Black participants, and 0.35 (95% CI: 0.14-0.56) for all other races/multiracial. The modified time trend analysis showed no significant difference in the PPRs before and after 2020 (White: t = 1.44, p = 0.22; Black: t = -0.99, p = 0.37; Other races/multiracial: t = -1.50, p = 0.21). The comparison to the 2014 State Surveillance Project yielded similar findings.

U.S.-based ALS trials significantly under-enroll non-White participants, and there are trends toward slight underrepresentation of women. Efforts to broaden trial enrollment amongst people with ALS will help with the generalizability of trial results and hasten trial completion.