Alzheimer's Assays Support Timely Diagnosis and Treatment Decision-Making

Presently, Alzheimer's disease (AD) diagnosis mainly relies on the process of elimination by conducting several evaluations such as cognitive tests, routine lab tests, and neuroimaging through an MRI or CT scan of the head. The accurate identification of AD can take several years, with the clinical criteria only being accurate 70-80% of the time. However, the use of AD-specific biomarkers can enhance medical decisions by identifying early pathological changes. Two FDA-approved cerebrospinal fluid (CSF) assays are now available to aid medical professionals in diagnosing AD biologically, thereby expediting diagnosis and treatment decisions.

Roche Diagnostics’ (Basel, Switzerland) Elecsys beta-Amyloid (1-42) CSF II (Abeta42) and Elecsys Total-Tau CSF assays (tTau) have received U.S. Food and Drug Administration (FDA) 510(k) clearance. The Elecsys AD CSF Abeta42 and tTau assays (used as a tTau/Abeta42 ratio) measure two biomarkers of AD’s pathology, beta-amyloid and tau proteins, in adults ages 55 and older being evaluated for the disease. Roche's FDA-cleared AD tests in the U.S. include two ratios comprising three assays with both ratios including Abeta42. The Elecsys beta-Amyloid (1-42) CSF II (Abeta42) and Elecsys Phospho-Tau (181P) CSF (pTau181) assays (used as a pTau181/Abeta42 ratio) approved by the FDA in 2022 and Elecsys beta-Amyloid (1-42) CSF II and Elecsys Total-Tau CSF assays (the tTau/Abeta42 ratio) are reflective of the main AD pathologies and aid clinicians in more completely defining the disease biologically, thus enhancing diagnostic accuracy.

Image: The FDA-cleared Elecsys tTau/Abeta42 ratio supports timely Alzheimer`s disease diagnosis and treatment decision-making (Photo courtesy of Roche)

In line with the recommended use for new AD medicines, the confirmation of amyloid pathology is essential. The FDA-approved methods for confirming amyloid pathology include CSF tests and PET scan imaging. The Elecsys AD CSF assays align with amyloid PET scan imaging results, and can potentially offer a more affordable and routine alternative to confirm amyloid pathology in the brain. They also provide a means of detecting both amyloid and tau biomarkers in a single test, without radiation exposure and can potentially identify AD pathology at early disease stages. PET scans are limited by their high cost, restricted availability, and the risks arising from patient exposure to radiation. Moreover, assessing both amyloid and tau AD biomarkers using PET necessitates multiple procedures and appointments, increasing radiation exposure. The Elecsys pTau181/Abeta42 ratio is already available, with the new Elecsys tTau/Abeta42 ratio expected to be accessible in Q4 2023. Roche's Elecsys AD CSF assays are registered in 46 countries worldwide, including those recognizing the CE mark.

"With the increasing likelihood of broad availability of new, Alzheimer's disease–specific therapies, now is the time for healthcare professionals and institutions to prepare to meet the demand for diagnostic methods to streamline and accelerate the path to the right treatment, at the right time, for people with Alzheimer's," said Brad Moore, president and CEO of Roche Diagnostics North America. "An early and accurate diagnosis can help patients, caregivers and physicians determine a path forward, and the Elecsys CSF assays support diagnosis at early disease stages, when treatment is most effective."

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