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August 17, 2026

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FDA Clears Tauklarify, a Second Tau PET Agent for Alzheimer’s

Robert Gultig 0 Comments

The FDA has approved Tauklarify, a new PET imaging tracer that detects tau tangles in patients being evaluated for Alzheimer’s disease.

A Second Tau-Targeted Tracer Reaches the Market

The FDA has approved florquinitau F 18 injection, marketed as Tauklarify by Enigma Biomedical USA, as a PET imaging agent for adults with cognitive impairment who are being evaluated for Alzheimer’s disease. The radiodiagnostic, long known in trials by its research name MK-6240, is designed to visualize tau neurofibrillary tangles, one of the two defining protein abnormalities in Alzheimer’s pathology alongside amyloid plaques. The approval followed a Fast Track designation and an NDA that the FDA accepted in October 2025, with a formal action date of August 13, 2026.

The clearance makes Tauklarify only the second F-18 tau PET tracer to reach the U.S. market, joining flortaucipir, sold as Tauvid, which Eli Lilly’s Avid Radiopharmaceuticals brought to market in 2020 as the first FDA-approved agent in the category. For years, Tauvid stood alone as the sole option for clinicians wanting to visualize tau burden directly on a PET scan rather than infer it indirectly. Tauklarify’s approval gives radiology and dementia-care programs a second commercially available choice, backed by a manufacturing and distribution relationship with Lantheus Holdings, which acquired the rights to the compound from Enigma Biomedical in 2023 and worked alongside the company through the approval process.

What the Clinical Data Showed

Tauklarify’s approval rests on two blinded-read imaging studies encompassing 617 total subjects, split roughly across mild Alzheimer’s dementia, mild cognitive impairment, and cognitively unimpaired participants. Independent readers, unaware of each patient’s clinical history or amyloid PET status, classified scans as positive or negative for tau pathology against a preestablished reference standard. Agreement between the tracer’s results and that standard was strong in both studies, with positive percent agreement running from roughly 68% to 88% and negative percent agreement from about 93% to 99%, depending on the study and the individual reader. Interreader consistency was also high, with a generalized Fleiss’ kappa near 0.92 in the larger study and 0.86 in the second. Safety data drawn from 1,734 participants showed a low rate of adverse events, most commonly headache, occurring in well under 1% of subjects.

Separately from the approval package, a multicentre, within-participant comparison known as the HEAD study put Tauklarify’s active compound head-to-head against Tauvid in the same patients. That trial found the newer tracer identified tau positivity considerably more often than the incumbent agent, particularly in cognitively unimpaired, amyloid-positive participants, where it flagged roughly twice as many tau-positive scans. Researchers involved in the comparison attributed the difference in part to the compound’s substantially higher binding affinity for tau tangles relative to flortaucipir, and reported better discriminative accuracy for identifying Alzheimer’s-related cognitive impairment overall.

Where the Agent Fits, and Where It Doesn’t

The FDA’s label is specific about the population Tauklarify is meant to serve: adults with cognitive impairment being evaluated for Alzheimer’s disease, not patients being assessed for other forms of tauopathy. The agency’s approval documentation flags a real limitation behind that language. Because the pivotal studies mainly enrolled patients expected to fall clearly at one end of the spectrum or the other, either cognitively unimpaired with a negative amyloid scan, or cognitively impaired with a positive one, the tracer’s accuracy in patients sitting in an earlier or intermediate stage of disease is less well established. A negative scan doesn’t rule out tau pathology, and a positive one isn’t a histopathologic diagnosis on its own, so clinicians are advised to weigh additional evaluation when a case remains ambiguous.

Practical handling requirements come with the approval as well. Health systems administering the tracer need standard radiopharmaceutical safety protocols to limit staff and patient radiation exposure, patients should hydrate before and after the scan and void frequently afterward, and CYP1A2 inducers, including tobacco smoking, should be avoided for at least seven days before administration. Lactating patients are advised to pause breastfeeding and discard pumped milk for a minimum of four hours post-injection.

Buyer and Procurement Implications

For imaging centers, academic medical centers, and health systems building out dementia-care pathways, Tauklarify’s arrival breaks what has effectively been a single-supplier market for F-18 tau PET tracers since 2020. Procurement teams negotiating radiopharmaceutical supply agreements now have grounds to evaluate a second vendor relationship, and the head-to-head sensitivity data gives clinical and pharmacy committees a concrete basis for tracer selection rather than a default choice by absence of alternatives. Given the drug-interaction restriction on CYP1A2 inducers and the hydration and voiding protocol, sites should also confirm patient-prep workflows are updated before scheduling scans, since the handling requirements differ in specifics from those governing amyloid PET agents already in routine use.

FAQ

What does Tauklarify detect, and who is it approved for?

Tauklarify is a PET imaging agent approved to detect tau neurofibrillary tangle pathology in the brains of adults with cognitive impairment who are being evaluated for Alzheimer’s disease. It is not approved for evaluating non-Alzheimer’s tauopathies.

How is Tauklarify different from Tauvid, the existing tau PET agent?

Both are F-18 radiotracers that image tau pathology, but a head-to-head comparison found Tauklarify’s compound identified tau positivity more often than Tauvid, particularly in early-stage cases, a difference researchers linked to its higher binding affinity for tau tangles.

What safety precautions come with Tauklarify administration?

Patients should avoid CYP1A2 inducers, including tobacco smoking, for at least seven days before the scan, hydrate and void frequently afterward, and lactating patients should pause breastfeeding and discard pumped milk for at least four hours post-injection.

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