Blood test may improve decision-making in Alzheimer’s disease
Key takeaways:
- The test met its primary endpoint of concordance with intended use, which was 99%.
- Patients with a positive result saw a 35% increase in prescriptions for Alzheimer’s disease medication after test implementation.
A blood-based biomarker test may be a reliable method for predicting or ruling out Alzheimer’s disease-related pathology and subsequently for assisting clinicians in formulating a treatment plan for patients, according to new research.
“The clinical integration of blood biomarkers for AD holds promise in enabling the early detection of pathology and timely intervention,” Mark Monane, MD, MBA, senior medical adviser at C2N Diagnostics, which funded the study, and colleagues wrote in Diagnostics. “The use of a blood biomarker test that is scalable and accessible as well as acceptable and equitable may address the unmet need in diagnostic testing.”
Monane and fellow researchers conducted a single-arm, multisite, prospective cohort study to assess how the PrecivityAD2 blood biomarker (BBM) test impacted clinical decision-making for 203 individuals (median age, 74 years; 53% women) who displayed signs of mild cognitive impairment or dementia consistent with AD.
According to the researchers, PrecivityAD2 combines plasma amyloid-beta 42/40 and the p-tau217/np-tau217 ratios (%p-tau217) to create an Amyloid Probability Score 2 (APS2), which assists in predicting the likelihood of brain amyloid plaques indicative of AD pathology.
After receiving each enrollee’s test results, participating physicians completed surveys on management strategies for each. The primary study outcome was twofold: patient selection based on concordance between clinician-ordered tests and PrecivityAD2 utilization, as well as APS2 score interpretation by clinicians themselves. Secondary outcomes included concordance with respect to age and AD symptom criteria, along with pre- and post-biomarker test evaluations.
Overall, the researchers reported a median APS2 score of 52, with about 49% of participants (n = 104) receiving a positive test result.
The clinical concordance with PrecivityAD2 test was 99% (200 of 203 tests), with non-concordance reported as testing outside intended use, including for patients aged younger than 55 years and those lacking MCI or dementia symptoms.
The composite primary endpoint of change in AD diagnostic certainty was 75%, while patients with a positive AP2 result saw a 35% increase in prescriptions for AD-related medication, according to a release related to the study.
From pre- to post-biomarker testing analysis, Monane and colleagues found a decrease in the mean clinician-reported AD probability from 53% to 11% among patients with negative results, along with an increase from 65% to 93% for patients testing positive.
“The overall outcome has been clinically meaningful changes in decision-making around AD diagnostic certainty, drug therapy management and additional brain amyloid evaluation among patients evaluated for cognitive impairment,” Robert M. Carlile, MD, neurology specialist at Palmetto Primary Care Physicians in Summerville, South Carolina, said in the release. This all increases our ability to develop diagnostic certainty and impact clinical management in patients.”
Reference:
Study highlights how C2N’s PrecivityAD2 blood biomarker test use improves clinical decision-making in the evaluation for Alzheimer’s disease. https://c2n.com/news-releases/study-highlights-how-c2ns-precivityad2-blood-biomarker-test-use-improvesnbsp-clinical-decision-making-in-the-evaluation-for-alzheimers-disease-nbspnbsp. Published Jan. 31, 2025. Accessed Feb. 5, 2025.