FDA Approves Tauklarify, a Tau PET Imaging Agent for Alzheimer's Disease

The U.S. Food and Drug Administration has approved Tauklarify, a new brain imaging agent for the evaluation of Alzheimer's disease. The drug, also known as MK-6240, is a radioactive diagnostic agent for positron emission tomography (PET) in adults, primarily indicated for adults with cognitive impairment who require physician assessment of abnormal tau protein accumulation in the brain. The twisted, insoluble fibrous deposits formed by tau protein are believed to be associated with neurodegenerative diseases such as Alzheimer's disease.

The developer, Lantheus, stated that the safety of Tauklarify was evaluated in two clinical trials involving more than 1,700 subjects. The incidence of adverse reactions was below 1%, with common reactions including headache, nausea, injection site reactions, dizziness, and abdominal discomfort, all occurring at low rates.

This approval was also based on two blinded read studies. Researchers analyzed PET images from more than 500 subjects across three clinical trials, including participants with mild cognitive impairment, patients with mild Alzheimer's disease dementia, and control subjects with unimpaired cognitive function. All subjects received an intravenous administration of approximately 185 megabecquerels (5 millicuries) of Tauklarify prior to Tau PET imaging.

In both studies, independent readers received training in image interpretation and assessed scans as positive or negative without knowledge of subjects' clinical information or β-amyloid PET results, to evaluate tau neurofibrillary tangle pathology. The first study enrolled 279 subjects, with positive agreement rates ranging from 80% to 88% and negative agreement rates from 98% to 99%; the second study enrolled 338 subjects, with positive agreement rates ranging from 68% to 82% and negative agreement rates from 93% to 99%. Inter-reader agreement remained high across both studies.

Lantheus also noted that the safety and effectiveness of Tauklarify for evaluating other brain diseases have not been established. The company has not yet specified immediate supply arrangements for the agent, stating that it will continue to support programs related to Alzheimer's disease treatment and evaluate appropriate pathways for broader commercial supply. Tauklarify was previously developed by Enigma Biomedical USA, which sold its subsidiary Cerveau Technologies to Lantheus in 2023 to complete the subsequent development of the drug.