The Food and Drug administration (FDA) approved flortaucipir (Tauvid; Eli Lilly, Indianapolis, IN) for positron emission tomography (PET) of the brain. Flortaupicir-PET is used to evaluate density and distribution of tau neurofibrillary tangles (NFTs) in people with cognitive disorders that may be a tauopathy, such as Alzheimer disease (AD). In clinical studies, flortaucipir had sensitivity ranging from 92% (95% CI, 80-97) to 100% (95% CI, 91-100) and specificity from 52% (95% CI ,34-70) to 92% (95% CI, 75-98) in the primary efficacy cohort. A neuropathologic diagnosis of AD requires demonstration of both beta-amyloid neuritic plaques and tau NFTs in the brain. Flortaucipir is the first and only approved diagnostic agent to image tau NFTs in the brain.
In these studies, readers' interpretations of premortem flortaucipir-PET scans from 64 cognitively normal and impaired terminally ill participants were compared to tau pathology findings at autopsy based on scoring provided by independent pathologists who were blinded to the PET scan results. When a different group of readers scored these and another 159 studies, interreader agreement was 0.87 (95% CI: 0.83, 0.91) across 241 participants, using the Fleiss' kappa statistic.
"The use of diagnostic imaging can help patients and their families plan for the future and make informed choices about their health and well-being, in addition to facilitating appropriate patient management for physicians," said Reisa Sperling, MD, professor of Neurology of Harvard Medical School, and director of the Center for Alzheimer Research and Treatment at Brigham and Women's Hospital and Massachusetts General Hospital. "Determining the anatomic distribution and density of tau NFTs in the brain was previously possible only at autopsy. Now we have a way to obtain this important information in patients."
The most common adverse reactions reported in clinical trials of flortaucipir were headache (1.4%), injection site pain (1.2%), and increased blood pressure (0.8%).
Michelle L. Dougherty, MD, FAES, FAAN
Allie Massaro, MD
Brad Klein, MD, MBA, FAAN, FAHS, FAANEM, and Raissa Villanueva MD, MPH, FAAN