C2N Diagnostics, a provider in advanced brain health diagnostics, announced the presentation of two research studies at the AD/PD 2023 International Conference on Alzheimer’s and Parkinson’s Diseases and related neurological disorders that bolster the role of the Precivity-related blood biomarkers (BBM) to help healthcare providers determine the presence or absence of amyloid plaques in the brain, a hallmark sign of Alzheimer’s disease.

These findings seek to underscore the ability of the Precivity-related blood biomarkers to help clinicians with the diagnosis of Alzheimer’s in cognitively impaired patients as well as risk prediction in unimpaired individuals, according to the provider.

Study Displays PrecivityAD2 Blood Test Accuracy

Sebastian Palmqvist, MD, PhD, and Oskar Hansson, MD, PhD, neurologists with Skåne University Hospital and Lund University in Sweden, used the PrecivityAD2 blood test (Research Use Only) that relies on precise mass spectrometry-based measurements of two key plasma proteins (p-tau and amyloid beta) implicated in Alzheimer’s.

The blood test reports out plasma p-tau217 Ratio (phospho-Tau217 / non-phospho-tau217) and plasma Aβ42/40 Ratio measures as well as the Amyloid Probability Score 2 (APS2) derived from a pre-established regression model based on those ratio measures. The APS2 results determine whether a patient is positive or negative for brain amyloid plaques based on a binary cutoff value.

The study included 307 patients (average age of 76 years old) with symptoms of cognitive impairment evaluated within primary care sites in Sweden. All patients received the PrecivityAD2 blood test as well as cerebrospinal fluid (CSF) analysis or an amyloid positron emission tomography (PET) scan. The Precivity-related blood biomarkers showed robust discrimination between amyloid positive and amyloid negative patients using CSF or PET biomarkers as the reference tests. In particular, the AUC of 0.91 (95% CI 0.88-0.94) for p-tau217 Ratio and AUC of 0.94 (95% CI 0.92-0.97) for the APS2 result were noted. Furthermore, the investigators’ work showed that primary care physicians (PCPs) without use of the blood test diagnosed only 60% of symptomatic Alzheimer’s correctly, leading to overdiagnosis in 23% and underdiagnosis in 17% of patients.

“The primary care physicians’ diagnosis certainty with standard of care only was low, which highlights that they are completely aware that currently available diagnostic tools in primary care are not adequate,” says Palmqvist. “The results we’ve seen so far indicate that this can radically change with a blood test for Alzheimer’s. The blood biomarkers showed robust clinical validity and accuracy among patients with comorbidities known to interfere with the performance of plasma. The PrecivityAD2 data represent the highest correlation data I’ve seen for a blood test against corresponding CSF biomarkers.”

In a separate study, Karly Cody, a PhD candidate at the University of Wisconsin-Madison Alzheimer’s Disease Research Center, found that in a cognitively unimpaired population of 281 individuals, the PrecivityAD2 blood test with the APS2 score had the highest diagnostic accuracy (AUC~96%) for detecting brain amyloid among other BBM studied alone or in combination.

As an extension of this study, 291 cognitively unimpaired individuals (average age 59) received blood tests and longitudinal cognitive follow-up (mean 8.2 years) to examine the associations of plasma biomarkers with cognitive status over time. When compared against the other individual biomarkers, an elevated value for the p-tau217 ratio (an integral component of the PrecivityAD2 blood test) was the best biomarker for predicting cognitive decline.

“We congratulate our collaborators from Skåne University Hospital, Lund University and University of Wisconsin for their outstanding work to further validate C2N’s blood tests in a variety of important clinical applications. These research findings add to the quality and number of Precivity-related biomarker measures we have reported through peer-reviewed publications, which now stands at approximately 10,000,” says Joel Braunstein, MD, CEO of C2N Diagnostics. “Both studies reinforce the perspective of the 2022 Clinical Trials On Alzheimer’s Disease Task Force report on the characteristics of an ideal blood biomarker. This means blood biomarkers with prospectively defined endpoints, validation across multiple different independent cohorts, suitability for use in primary care, and the ability to help with both diagnosis and risk prediction. In particular, Dr. Palmqvist’s work highlights that as AD-specific treatments are approved and become widely accessible, the need for detection and accurate diagnosis will be amplified.”