Roche’s test measures levels of pTau181 in plasma to identify patients unlikely to have Alzheimer’s-related amyloid pathology.
Pharma and diagnostics giant Roche today revealed it has received clearance from the US FDA for its Elecsys pTau181 test, making it the only FDA-cleared blood-based biomarker test that can be used by doctors to help rule out Alzheimer’s-related amyloid pathology.
The Roche test measures levels of phosphorylated Tau (pTau181) protein in human plasma, a marker associated with Alzheimer’s pathology that includes amyloid plaques and tau aggregates. Developed in partnership with Eli Lilly, the test is designed to help clinicians identify patients in early stages of impairment who are unlikely to have Alzheimer’s-related changes, allowing them to focus further diagnostic resources on those more likely to have the disease.
While blood tests designed to confirm cases of Alzheimer’s tend to grab the headlines, the ability to rule out cases is viewed as key step towards streamlining the diagnostic pathway for the disease. The arrival of an effective rule-out blood-based test could enable clinicians to more easily differentiate Alzheimer’s from other causes of cognitive decline, reducing inappropriate prescribing and clarifying ambiguous cases, and may help identify appropriate candidates for anti-amyloid therapies or clinical trials. A simple blood test could also help reduce unnecessary use of more invasive and costly confirmatory procedures such as positron emission tomography scans or lumbar punctures.
“By bringing Alzheimer’s blood-based biomarker testing into primary care, we can help patients and their clinicians get answers sooner to support them earlier in their journeys,” Roche Diagnostics CEO Brad Moore.
Roche evaluated the test in a multicenter clinical study representative of a primary care population at early disease stages. The data showed that Elecsys pTau181 could rule out Alzheimer’s pathology with a 97.9% negative predictive value.
Earlier this year, we spoke with Dr Maria-Magdalena Patru, who leads the neurology medical team at Roche Diagnostics US, who told us she expected the future of Alzheimer’s diagnosis would comprise a panel of biomarkers, rather than a single test.
“It’s almost never just about one biomarker for a disease, especially in Alzheimer’s, which has such a complex pathology,” she said. “Clinicians are going to need a panel of biomarkers, to aid in AD diagnosis and disease staging, but most importantly a panel that encompasses biomarkers for differential diagnosis with other causes of dementia.”
The FDA clearance follows a similar regulatory milestone in Europe, where Elecsys pTau181 became the first CE-marked blood test designed to help rule out Alzheimer’s-associated amyloid pathology.
