FDA cleared the Elecsys pTau181 test as the first blood-based biomarker to aid in the initial assessment of Alzheimer’s disease and other causes of cognitive decline that can be used in the primary care setting, Roche announced on Monday.
The test measures plasma levels of phosphorylated tau 181 (p-tau181), one of the key markers of amyloid plaque and tau aggregate pathology behind Alzheimer’s disease, and is intended for patients 55 and older who present with signs, symptoms, or complaints of cognitive decline to rule out Alzheimer’s-related amyloid pathology in conjunction with other clinical information.
“By enabling use in primary care, the Elecsys pTau181 test has the potential to significantly broaden patient access to minimally invasive testing and helps preserve specialist resources,” Roche said in a statement. “Primary care clinicians can better guide appropriate referrals so neurologists can focus on the patients most likely to need advanced evaluation and treatment.”
Clearance was supported by a multicenter, non-interventional clinical study in an early disease-stage, low-prevalence population reflective of what is seen in primary care. Among the 312 participants, the p-tau181 test ruled out Alzheimer’s pathology with a 97.9% negative predictive value.
Earlier this year, the Alzheimer’s Association issued guidelines backing clinical use of blood tests for Alzheimer’s disease biomarkers that have at least 90% sensitivity and 75% specificity for initial triage in which a negative finding rules out the condition and a positive result leads to additional testing, such as PET scans for amyloid-beta plaques or cerebrospinal fluid biomarker analysis.
In May, the FDA cleared the first blood-based diagnostic test for Alzheimer’s disease, the Lumipulse G pTau 217/β-Amyloid 1-42 Plasma Ratio, intended to be used in people 55 and older who have signs and symptoms of the disease but who present at specialized care settings — not primary care.
Early diagnosis of Alzheimer’s disease has come to the fore with the availability of monoclonal antibodies such as lecanemab (Leqembi) and donanemab (Kisunla) to treat early symptomatic cases with confirmed amyloid pathology.
