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This Viewpoint discusses why it’s important for Alzheimer clinical trials to be inclusive and enroll diverse populations that include underrepresented racial, ethnic, and sociocultural groups.

IMPORTANCE: The goal of preclinical Alzheimer disease (AD) clinical trials is to move diagnosis and treatment to presymptomatic stages, which will require biomarker testing and disclosure. OBJECTIVE: To assess the short-term psychological outcomes of disclosing amyloid positron emission tomography results to older adults who did not have cognitive impairment. DESIGN, SETTING, AND PARTICIPANTS: This observational study included participants who were screening for a multisite randomized clinical trial that began on February 28, 2014, and is anticipated to be completed in 2022. Participants aged 65 to 85 years who had no known cognitive impairments underwent an amyloid positron emission tomography scan and learned their result from an investigator who used a protocol-specified process that included prescan education and psychological assessments. This report compares participants with elevated amyloid levels with at least 1 available outcome measure with participants who did not have elevated amyloid levels who enrolled in an observational cohort study and received further evaluations. Data were collected from April 2014 to December 2017 and analyzed from March 2019 to October 2019. EXPOSURES: A personal biomarker result described as either an elevated or not elevated amyloid level. MAIN OUTCOMES AND MEASURES: To assess the immediate and short-term psychological outcome of disclosure, the following validated measures were used: the Geriatric Depression Scale, the state items from the State-Trait Anxiety Inventory, and the Columbia Suicide Severity Rating Scale, as well as the Concerns About AD Scale and the Future Time Perspective Scale to assess changes in participants’ perceived risk for AD and perceived remaining life span, respectively. RESULTS: A total of 1167 participants with elevated amyloid levels and 538 participants with not elevated amyloid levels were included. Participants had a mean (SD) age of 71.5 (4.7) years, 1025 (60.1%) were women, and most were white (1611 [94.5%]) and non-Latino (1638 [96.1%]). Compared with participants who learned that they had a not elevated amyloid result, individuals who learned of an elevated amyloid result were no more likely to experience short-term increases in depression (mean [SD] change in the Geriatric Depression Scale score, 0.02 [1.3] vs 0.04 [1.3]; P = .90), anxiety (mean [SD] change in State-Trait Anxiety Inventory score, –0.02 [3.2] vs –0.15 [3.0]; P = .65), or suicidality (mean [SD] change in the Columbia Suicide Severity Rating Scale score, 0.0 [0.4] vs –0.01 [0.5]; P = .67). Participants with elevated amyloid levels had increased Concern About AD scores (raw change in scores: elevated amyloid group, 0.8 [3.9]; not elevated amyloid group, –0.4 [3.8]; P

Importance Early identification of Alzheimer disease (AD) is important for clinical management and affords the opportunity to assess potential disease-modifying agents in clinical trials. To our knowledge, this is the first report of a randomized trial to prospectively enrich a study population with prodromal AD (PDAD) defined by cerebrospinal fluid (CSF) biomarker criteria and mild cognitive impairment (MCI) symptoms. Objectives To assess the safety of the γ-secretase inhibitor avagacestat in PDAD and to determine whether CSF biomarkers can identify this patient population prior to clinical diagnosis of dementia. Design, Setting, and Participants A randomized, placebo-controlled phase 2 clinical trial with a parallel, untreated, nonrandomized observational cohort of CSF biomarker-negative participants was conducted May 26, 2009, to July 9, 2013, in a multicenter global population. Of 1358 outpatients screened, 263 met MCI and CSF biomarker criteria for randomization into the treatment phase. One hundred two observational cohort participants who met MCI criteria but were CSF biomarker-negative were observed during the same study period to evaluate biomarker assay sensitivity. Interventions Oral avagacestat or placebo daily. Main Outcomes and Measure Safety and tolerability of avagacestat. Results Of the 263 participants in the treatment phase, 132 were randomized to avagacestat and 131 to placebo; an additional 102 participants were observed in an untreated observational cohort. Avagacestat was relatively well tolerated with low discontinuation rates (19.6%) at a dose of 50 mg/d, whereas the dose of 125 mg/d had higher discontinuation rates (43%), primarily attributable to gastrointestinal tract adverse events. Increases in nonmelanoma skin cancer and nonprogressive, reversible renal tubule effects were observed with avagacestat. Serious adverse event rates were higher with avagacestat (49 participants [37.1%]) vs placebo (31 [23.7%]), attributable to the higher incidence of nonmelanoma skin cancer. At 2 years, progression to dementia was more frequent in the PDAD cohort (30.7%) vs the observational cohort (6.5%). Brain atrophy rate in PDAD participants was approximately double that of the observational cohort. Concordance between abnormal amyloid burden on positron emission tomography and pathologic CSF was approximately 87% (κ = 0.68; 95% CI, 0.48-0.87). No significant treatment differences were observed in the avagacestat vs placebo arm in key clinical outcome measures. Conclusions and Relevance Avagacestat did not demonstrate efficacy and was associated with adverse dose-limiting effects. This PDAD population receiving avagacestat or placebo had higher rates of clinical progression to dementia and greater brain atrophy compared with CSF biomarker–negative participants. The CSF biomarkers and amyloid positron emission tomography imaging were correlated, suggesting that either modality could be used to confirm the presence of cerebral amyloidopathy and identify PDAD. Trial Registration clinicaltrials.gov Identifier:NCT00890890