Roche has obtained European approval for a blood test to help rule out Alzheimer’s disease, allowing patients to avoid additional exams for the condition after showing signs of cognitive decline.
The company’s Elecsys test, developed in collaboration with the drugmaker Eli Lilly & Co., searches for the phosphorylated tau-181 protein in the blood, which has been linked to the presence of amyloid plaque build-ups in the brain.
According to Roche, the in vitro diagnostic can be employed in the primary care setting for frontline testing. The company estimates that up to 75% of people living with symptoms remain undiagnosed—and that those who have received an Alzheimer’s diagnosis typically waited nearly three years after symptoms began.
“The burden of Alzheimer’s disease on society and healthcare systems is increasing as the world’s population ages,” Roche Diagnostics CEO Matt Sause said in a statement.
“With Elecsys pTau181, doctors can give patients and their caregivers the clarity they need when establishing the cause of cognitive decline,” Sause said. “By enabling an earlier and less invasive diagnosis, this test has the potential to improve patient outcomes and decrease costs for healthcare systems worldwide.”
The test’s CE mark was based on findings from an international clinical trial of 787 participants between the ages of 55 and 80, demonstrating a negative predictive value of 93.8% and a false-negative rate of 16.4% when matched with amyloid readings in PET brain scans. Roche said the regulatory green light marked the first for a blood test to rule out Alzheimer’s under the European Union’s In Vitro Diagnostic Regulation, or IVDR.
Roche and Eli Lilly have also worked together on a plasma-based Elecsys diagnostic that checks for pTau-181 as well as apolipoprotein E4, a common genetic risk factor for Alzheimer’s. That rule-out test previously received a breakthrough tag from the FDA—as has an Elecsys plasma assay that quantifies a separate form of the phosphorylated tau brain protein, known as pTau-217.
Roche said that a stand-alone test for pTau-217 demonstrated more stable results than one comparing a ratio of pTau-217 to amyloid beta 42 among blood and plasma samples at room and refrigerator temperatures.