Data from the CLARITY trial earlier this year was supposed to be the crowning glory of the amyloid hypothesis, vindication for proponents of this long-held but much-maligned theory of Alzheimer’s disease.
Yet the results left many feeling underwhelmed, and even the study authors noncommittal.
The CLARITY trial has many admirable features. It recruited close to 1800 people from around the world, pretty balanced between women and men. While the majority were white, 17% of the cohort was Asian and 12% Latino.
Choice of primary and secondary outcomes were impeccable. The primary outcome was the Clinical Dementia Rating sum of boxes (CDR-SB), a scorecard of sorts rated by a clinician across the domains of memory, orientation, problem solving, community affairs, home duties and personal care. Secondary outcomes included standard measures of global cognition, daily function, as well as biomarkers in the brain, from the CSF and blood.