FDA Approves Lantheus Alzheimer’s Tau PET Imaging Agent Tauklarify

The U.S. Food and Drug Administration has approved Lantheus Holdings’ Tauklarify, a radioactive imaging agent designed to help identify tau neurofibrillary tangle pathology in adults with cognitive impairment who are being evaluated for Alzheimer’s disease.

The approval gives Lantheus a new FDA-cleared asset in neurological imaging at a time when the company is building a broader radiodiagnostic portfolio. Tauklarify, also known during development as MK-6240, is used with positron emission tomography, or PET, brain scans. It is not an Alzheimer’s treatment and the scan result is not meant to stand alone as a definitive diagnosis.

Lantheus announced the approval on August 14 at 8:00 a.m. ET. The company said the agent is indicated to identify patients with tau neurofibrillary tangle pathology, one of the characteristic pathological features associated with Alzheimer’s disease.

Approval is based on two blinded PET-reading studies

The FDA decision was supported by two blinded-read studies using Tauklarify PET images from participants enrolled in three clinical trials. The studies included people with mild cognitive impairment, mild Alzheimer’s disease dementia and cognitively unimpaired participants, allowing the imaging agent to be assessed across different levels of cognitive function.

In Study 1, independent readers evaluated images from 279 participants. Positive percent agreement ranged from 80% to 88%, while negative percent agreement ranged from 98% to 99%. The generalized Fleiss’ kappa, a measure of agreement among readers, was 0.92. In Study 2, which included 338 participants, positive percent agreement ranged from 68% to 82% and negative percent agreement ranged from 93% to 99%, with a generalized Fleiss’ kappa of 0.86.

The studies did not simply compare scan interpretations against a tissue-confirmed pathology result for every participant. Instead, scans were classified as positive or negative for tau neurofibrillary tangle pathology and compared with a pre-established reference standard based on cognitive status and amyloid beta PET findings. That distinction is important when interpreting the reported performance figures.

The label also contains a warning about misdiagnosis. Lantheus says a negative Tauklarify scan does not necessarily exclude tau pathology, and a positive scan does not necessarily establish histopathologically confirmed tau pathology. Performance may also be lower in patients at earlier stages of the pathological spectrum. The safety and effectiveness of Tauklarify have not been established for evaluating tauopathies other than Alzheimer’s disease.

Safety was evaluated in 1,734 people. The most commonly reported adverse reactions were headache at 0.7%, nausea at 0.2%, and injection-site reactions, dizziness and abdominal discomfort at 0.1% each. The product also carries the radiation risks inherent to radioactive diagnostic agents. Patients are advised to hydrate around administration and urinate frequently afterward to reduce radiation exposure.

Commercial opportunity comes with unresolved launch questions

FDA approval converts Tauklarify from a late-stage development asset into an approved product, but it does not yet establish how quickly it will become a meaningful commercial contributor. Lantheus said it plans to continue supporting Alzheimer’s therapeutic programs through its Pharma Solutions business while it evaluates the appropriate path toward broader commercial availability.

The company has not announced a broad U.S. commercial launch date. In its approval release, Lantheus identified several factors that could affect commercialization, including the timing of a launch, market acceptance, competition, reimbursement, coding and payment, intellectual-property protection, and its ability to develop sufficient manufacturing capacity. Those are practical constraints Lantheus itself identified as relevant to turning the approval into a broader commercial product.

Tauklarify will enter a tau-imaging market that already includes Eli Lilly’s Tauvid, an F-18 tau PET agent approved in 2020. Reuters reported that B. Riley Securities analyst Yuan Zhi estimates the existing tau-imaging market at less than $100 million annually and projects Tauklarify sales of less than $50 million a year by 2030. Those figures are analyst estimates, not company guidance.

The relatively small current market helps explain why approval alone should not be treated as proof of a large near-term earnings contribution. Reuters also noted that clinical use of tau imaging remains more limited than amyloid imaging because there is currently no approved Alzheimer’s therapy that directly targets tau. The commercial value of Tauklarify could therefore depend partly on how Alzheimer’s treatment pathways evolve, including whether future disease-modifying therapies make tau status more important for patient selection, staging or monitoring.

Lantheus itself made a similar point in its approval announcement. Among the risks it listed were the development of disease-modifying Alzheimer’s treatments and whether Tauklarify is incorporated into prescribing information or clinical guidelines for such therapies. That makes the approval commercially relevant without making future adoption certain.

Tauklarify expands Lantheus’s existing neurology imaging business

For investors, Tauklarify is also notable because Lantheus already has an established position in Alzheimer’s imaging through Neuraceq, an amyloid beta PET imaging agent. Neuraceq generated $39.6 million in revenue during the second quarter of 2026 and $75.1 million in the first six months of the year, according to Lantheus’s latest quarterly results. Tauklarify gives the company a second approved neurological imaging asset that targets a different Alzheimer’s-related pathology.

The distinction between amyloid and tau is commercially and clinically relevant. Amyloid PET imaging detects amyloid plaques, which can begin accumulating before obvious cognitive symptoms, while tau imaging is designed to show abnormal tau tangles. Reuters noted that the amount and spread of tau are more closely associated with worsening memory and thinking problems. Tauklarify therefore broadens Lantheus’s Alzheimer’s imaging exposure rather than simply duplicating Neuraceq.

The approval also completes a regulatory path that has been visible to investors for nearly a year. The FDA accepted Lantheus’s new drug application for MK-6240 in October 2025 and gave it a Prescription Drug User Fee Act target action date of August 13, 2026. The agent had previously received Fast Track designation. Lantheus acquired Cerveau Technologies, which held rights to develop and commercialize MK-6240, in 2023.

Tauklarify is arriving as Lantheus itself is in the middle of a larger corporate transition. On August 3, Curium agreed to acquire Lantheus in a transaction valued at up to approximately $8 billion, including contingent value rights tied to specified commercial milestones. Lantheus said earlier this month that the proposed combination would create a radiopharmaceutical company spanning diagnostics and therapeutics. Friday’s Tauklarify approval does not alter the disclosed merger terms, but it adds another approved diagnostic asset to the portfolio Curium is seeking to acquire.

Lantheus reported $388.2 million of worldwide revenue in the second quarter, up 2.7% from a year earlier, with its products spanning oncology, neurology and cardiology imaging. Tauklarify now moves from the company’s development pipeline into its approved product set. The next material issue for its financial contribution is no longer regulatory clearance, but how Lantheus approaches manufacturing, reimbursement and broader commercial availability.