FDA Approves First Tau Pathology Imaging Agent Tauvid (flortaucipir F18) for Alzheimer’s Disease Evaluation

Today, the U.S. FDA announced the approval of Eli Lilly and Company’s Tauvid (flortaucipir F18) injection for marketing. This is the first drug approved by the FDA to help image tau pathology in the brain. Tauvid is a radioactive diagnostic agent indicated for adult patients with cognitive impairment who are being evaluated for Alzheimer’s disease. Tauvid is used with positron emission tomography (PET) imaging to estimate the density and distribution of aggregated tau neurofibrillary tangles (NFTs) in the brain, one of the key pathological hallmarks of Alzheimer’s disease.

Alzheimer's disease is a progressive disorder, with initial symptoms manifesting as mild memory loss. Tau neurofibrillary tangles and amyloid plaque deposition are considered hallmarks of Alzheimer's disease. In patients with Alzheimer's disease, pathologically altered tau protein accumulates within neurons in the brain, forming neurofibrillary tangles. After intravenous administration, Tauvid binds to areas in the brain where this misfolded tau protein has accumulated. Subsequent brain imaging using positron emission tomography (PET) scans can help identify the presence of tau pathology.

The safety and efficacy of Tauvid imaging were evaluated in two clinical studies. In each study, five readers interpreted the Tauvid images to determine whether they were positive or negative for tau pathology, while blinded to the patients’ clinical information.

The first study enrolled 156 patients with terminal illnesses who consented to undergo Tauvid imaging and participate in a postmortem brain donation program. Among the 64 patients who died within nine months after the Tauvid brain scan, independent pathologists evaluated the density and distribution of neurofibrillary tangles (NFTs) in their postmortem brain tissues. Comparative analysis revealed that readers interpreting the Tauvid images had a higher probability of correctly identifying patients with tau pathology, while demonstrating moderate to high accuracy in assessing patients without tau pathology.

In addition to including patients with terminal illness as in the first study, the second study also enrolled 159 patients with cognitive impairment undergoing Alzheimer’s disease assessment (the indicated patient population). The study assessed the agreement between Tauvid readers’ interpretations and other assessment results. Agreement was defined as 1 for complete concordance and 0 for complete discordance. In this study, the overall agreement across all 241 patients was 0.87. Subgroup analysis showed an agreement of 0.82 among the 82 patients with terminal illness and 0.90 among the 159 patients with cognitive impairment.

In this study, patients with cognitive impairment had relatively severe disease; the ability of Tauvid to detect tau pathology may be reduced in earlier-stage patients with milder cognitive symptoms.

“Alzheimer’s disease is a devastating condition,” said Dr. Charles Ganley, Director of the Office of Professional Medical Affairs at the FDA’s Center for Drug Evaluation and Research. “This approval will provide healthcare professionals with a new type of brain scan for patients undergoing evaluation for Alzheimer’s disease. It is the first drug approved for imaging tau pathology. This represents a significant advance for patients with cognitive impairment who are being evaluated for their condition.”

References:

[1] FDA Approves First Drug to Image Tau Pathology in Patients Being Evaluated for Alzheimer’s Disease. Retrieved May 28, 2020, from https://www.fda.gov/news-events/press-announcements/fda-approves-first-drug-image-tau-pathology-patients-being-evaluated-alzheimers-disease

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