The Potential of Blood Tests to Improve Screening and Monitoring in Alzheimer Disease Clinical Trials: Ronald C. Petersen, MD, PhD

WATCH TIME: 3 minutes

"These trials are enormously expensive. If we have to PET scan thousands of people to find out who’s eligible, that’s not practical, it’s not affordable. But the plasma markers are giving us an index that we could do a blood test. If the person is positive on the blood test, then move them forward to PET imaging or cerebrospinal fluid analysis."

Toxic oligomers of the protein amyloid-ß, considered one of the first stages of Alzheimer disease (AD), can start to form more than a decade before symptoms appear and before other known disease markers form. Patients in the earliest stages of AD have been typically used in drug development to ensure a maximum benefit of a drug; however, identifying patients and their cognitive status has been a challenge. While there has been substantial expansion in plasma biomarkers, they often come with significant cost and accessibility issues.

In recent years, there have been several companies developing blood tests as a way to detect amyloid plaques associated with AD. In May 2022, the FDA authorized the Lumipulse G ß-Amyloid Ratio as the first in vitro diagnostic test for early detection, intended for adults aged 55 years and older presenting with cognitive impairment. Months later, Roche’s Elecsys CSF phospho-tau 181/Aß42 assay also got FDA’s greenlight to be used in clinical practice as a diagnostic aid.

Ronald C. Petersen, MD, PhD, and colleagues recently published a paper on the definition of clinically meaningful benefit in AD clinical trials, stressing the importance of early intervention. In an interview with NeurologyLive®, Petersen, director of the Alzheimer’s Disease Research Center at Mayo Clinic, discussed the ways to overcome the current issue of biomarker accessibility, the role blood tests will play, and the ways to monitor patients effectively throughout a trial.