C2N Diagnostics introduced its second-generation liquid biopsy technology to detect Alzheimer’s late last year. Now, results from two new studies have brought its efficacy in ensuring improved diagnosis from doctors and predicting cognitive decline over time to light.
The original PrecivityAD test to screen for Alzheimer’s used mass spectrometry to measure amyloid beta 42 and 40, which were potential indicators for Alzheimer’s. The test also looked for apolipoprotein E (ApoE) as a potential indicator, and the resulting Aβ42/40 ratio and ApoE genotype were combined with the C2N algorithm to calculate the amyloid probability score (APS) in patients.
Despite the fact that follow-up testing was necessary to produce a definitive diagnosis, the APS was able to predict the risk of patients developing Alzheimer’s.
Amyloid plaques in the brain are considered a classic sign of Alzheimer’s. The new expanded version of the C2N, by combining the Aβ42/40 ratio with other ratios like ones for comparing the presence of phosphorylated and non-phosphorylated tau217, improves the ability of the test to determine the presence of brain amyloid plaques.
The results for whether or not a patient is brain amyloid plaque positive or negative are shown as APS2.
The new studies demonstrating the efficacy of the PrecivityAD2 test were presented at the annual AD/PD conference that is dedicated to highlighting new findings surrounding Alzheimer’s and Parkinson’s diseases.
The first study presented by the company at the conference showed that the new test helped improve doctors’ diagnoses of Alzheimer’s in a study conducted on over 300 Swedish patients who were showing symptoms of cognitive impairment.
Each patient in the study, along with the current standards for Alzheimer’s screening which are either a cerebrospinal fluid analysis or an amyloid PET scan, was given a PrecivityAD2 test. According to C2N, when results from the PrecivityAD2 test were not factored in, it resulted in an overdiagnosis of 23% and an underdiagnosis of 17%, and only 60% of the time was an accurate diagnosis given.
It is also to be noted that when compared to the results of the other tests in the study, APS2 results achieved an area under the curve of 94%.
According to Sebastian Palmqvist, M.D., Ph.D., a neurologist who helped lead the study, “The primary care physicians’ diagnosis certainty with the standard of care only was low, which highlights that they are completely aware that currently available diagnostic tools in primary care are not adequate. The results we’ve seen so far indicate that this can radically change with a blood test.”
The second study that the company presented pitted the PrecivityAD2 test against other blood biomarker tests for Alzheimer’s and found that the PrecivityAD2 test scored the highest diagnostic accuracy. In fact, the area under the curve for the test was over 95%.
The study focused on individuals showing no signs of cognitive impairment and had over 280 participants.
By conducting further research on nearly 300 patients over a span of 8 years, researchers also studied the use of blood-based biomarkers in predicting cognitive decline over time. Researchers eventually discovered that the best indicator for cognitive decline over time was also the p-tau217 ratio included in the PrecivityAD2 test.