Objective:

To examine eligibility to receive donanemab treatment in a population-based study of cognitive aging.

Background:

We recently demonstrated that applying clinical trial inclusion and exclusion criteria to the population-based Mayo Clinic Study of Aging (MCSA) participants would exclude most patients with early Alzheimer’s disease (AD) from qualifying for lecanemab and aducanumab treatment. In a more recent clinical trial, donanemab was found to slow the rate of decline in early AD, but selection criteria uniquely also included a tau PET assessment to help identify optimal candidates. The proportion of patients with early symptomatic AD eligible for donanemab trial in a community-based setting is unknown.

Design/Methods:

817 MCSA participants (aged 60-85 years) were clinically diagnosed with MCI or mild AD dementia. Donanemab eligibility criteria were further applied to this sample and tau PET positivity was visually assessed.

Results:

782 (96% of 817) participants had an MMSE score between 20-28 and 13 had MRI/PET contraindications, leaving 769 participants meeting the inclusion criteria before any PET scan. 275 participants had amyloid PET available, of whom 130 also had a tau PET at the same visit; 56 (43% of 130) patients were determined to be amyloid positive (A+), and of those, 27 were determined to be tau positive (T+) as well, based on visual assessment. Exclusion criteria from the trial (e.g., central nervous system-related exclusions, history of malignancy, neuroimaging findings) further reduced the eligible population to 13 (23% of 56).

Conclusions:

The percentage of individuals with early symptomatic AD who potentially qualify for anti-amyloid trials remains limited.