NEW YORK – An international committee of clinicians and researchers on Sunday released new draft guidelines for diagnosing Alzheimer's disease, including a proposal to use blood-based biomarker tests in the clinical setting.
The 22-person steering committee, convened by the Alzheimer's Association and the US National Institutes of Health's National Institute on Aging (NIA), presented the guidelines at the Alzheimer's Association International Conference in Amsterdam. The new proposed guidelines would revise a framework initially released by the Alzheimer's Association and NIA in 2018.
Alzheimer's is currently diagnosed based on results from either a PET scan or cerebrospinal fluid analysis. However, members of the steering committee suggested that blood-based biomarker tests will be able to provide patients with accurate diagnoses earlier and help to identify relevant research trials and access to approved biomarker-targeted treatments.
"A new generation of biomarkers is now available to detect Alzheimer's disease more and more effectively," Charlotte Teunissen, a professor of neurochemistry at Amsterdam UMC who was involved in drafting the new guidelines, said in a statement. A blood test can be ordered by a general practitioner and is likely inexpensive compared to other diagnostic methods.
The committee recommended two core biomarkers that can be used to diagnose Alzheimer's: amyloid-beta proteinopathy, which can be diagnosed from a blood-based test by evaluating plasma amyloid-beta 42/40 ratio, and tau proteinopathy, which can be diagnosed by measuring pTau-181 and pTau-217.
The guidelines also highlight injury and dysfunction of neuropil and inflammation as two biomarkers that are not specific to Alzheimer's but are important to the disease's pathogenic pathway.
In the proposed guidelines, the authors acknowledge that biomarkers should be interpreted within a clinical context and not used in isolation, and that, with the current technology and evidence available, it's not possible to determine the proportion of cognitive deficit observed in an individual that can be attributed to Alzheimer's versus other neuropathologies.
Clinicians and scientists can submit public comments on the draft guidelines for 30 days on the Alzheimer's Association website.
The guidelines come on the heels of the US Food and Drug Administration granting full approval for the Alzheimer's drug Leqembi (lecanemab), developed by Eisai and Biogen, which is indicated for adult Alzheimer's patients with mild cognitive impairment or mild dementia and who have confirmed presence of amyloid-beta pathology.
In the European Medicines Agency, Leqembi's marketing authorization application has been accepted and is under review.