Primary Endpoints in Current Phase II/III Trials for Alzheimer Disease: A Systematic Survey of Trials Registered at ClinicalTrials.gov.

This study examined the primary and secondary endpoints used by recent phase II/III randomized controlled trials (RCTs) of drugs for the Alzheimer disease. We searched the Clinical Trials.gov database to identify all RCTs registered from January 1, 2011 until August 19, 2018. We identified 122 RCTs and examined primary and secondary endpoints most commonly used. The median number of primary endpoints was 1 (range: 1 to 48) and the median number of secondary endpoints was 4 (range: 1 to 19). Cognitive function was used as a primary endpoint by 59% of the RCTs identified. Although few trials included a primary outcome set that fulfilled the US Food and Drug Administration (FDA) or European Committee for Medicinal Products for Human Use (CHMP) requirements, these were met by a combination of the primary and secondary outcomes of more than half of the trials.