FDA Approves Tauklarify (MK-6240) For Tau Pathology Detection in Alzheimer Disease

Tauklarify (previously MK-6240), a new tau targeting imaging agent for detection of Alzheimer disease, has been approved by the US Food and Drug Administration (FDA).¹ The positron emission tomagraphy (PET) imaging agent is designed to bind selectively to aggregated tau protein to identify tau neurofibrillary tangle pathology in patients being evaluated for Alzheimer disease.

"For clinicians and researchers, tau PET imaging is an important tool for identifying tau pathology in the brain and advancing our understanding of Alzheimer disease," said Keith Johnson, professor of neurology and radiology at Harvard Medical School.¹ "The use of sensitive quantitative tau PET imaging is essential for increasing our understanding of potential disease impacts and moving novel treatments forward,” he added.

The approval is supported by data from 2 pivotal phase 3 studies evaluating MK-6240's sensitivity and specificity for detecting tau NFT pathology, along with earlier preclinical and clinical work showing high affinity for tau and limited off-target binding.^2,3 Two blinded read studies analyzed Tauklarify PET images from over 500 patients across 3 clinical trials. In the read studies, independent blinded readers interpreted scans with Tauklarify and classified positive or negative for tau neurofibrillary tangle pathology. Patients included had mild cognitive impairment, mild Alzheimer disease, and no cognitive impairment. All subjects received 185 MBq (5mCi) of Tauklarify for imaging. Safety was evaluated in over 1700 subjects.

"Today’s approval of Tauklarify reflects both the increasing importance of tau imaging in Alzheimer disease assessment and the innovative development program that supported this milestone," said Mary Anne Heino, executive chairperson and chief executive officer of Lantheus. She emphasized, "As the field continues to advance, clinicians are seeking a more complete understanding of this disease, with tau PET imaging providing information that complements amyloid PET and other diagnostic tools."

From the read studies, both showed high rates of agreement across readers: study 1 had an 80% to 88% positive percent agreement, and study 2 had a 68% to 82% positive percent agreement. In evaluating safety, the most commonly reported adverse reactions were headache (0.7%), nausea (0.2%), injection site reactions (0.1%), dizziness (0.1%), and abdominal discomfort (0.1%).

MK-6240 is an F18-labeled tau-targeted PET imaging agent intended to detect tau neurofibrillary tangle pathology in patients with cognitive impairment being evaluated for Alzheimer disease. The molecule has shown a high affinity for tau and limited off-target binding in preclinical and clinical studies. However, the safety and efficacy of Tauklarify have not been established for evaluation of non-Alzheimer tauopathies.

Developers of this agent noted that approval of Tauklarify will complement beta-amyloid PET imaging and emerging blood-based diagnostics for Alzheimer disease. Approval of the agent comes after it received New Drug Application approval in October 2025, and previous Fast Track designation.⁴

Tauklarify should not be used with CYP12A inducers, including tobacco, at least 7 days before administration. Patients breastfeeding should discontinue breastfeeding temporarily when receiving Tauklarify.

References

1. Lantheus announces FDA approval of Tauklarify (florquinitau F18 injection), an F18-labeled tau PET imaging agent for Alzheimer disease. Press release. August 14, 2026. Accessed August 14, 2026. https://www.benzinga.com/pressreleases/26/08/g61205172/lantheus-announces-fda-approval-tauklarify-florquinitau-f-18-injection-f18-labeled-tau-pet-imaging-a

2. Lohith TG, Bennacef I, Vandenberghe R, et al. Brain imaging of Alzheimer dementia patients and elderly controls with 18F-MK-6240, a PET tracer targeting neurofibrillary tangles. J Nucl Med. 2019;60(1):107-114.

3. Lantheus announces Alzheimer disease radiodiagnostic MK-6240 meets coprimary endpoints in 2 pivotal studies. Press release. April 30, 2025. Accessed August 13, 2026. https://lantheusholdings.gcs-web.com/news-releases/news-release-details/lantheus-announces-alzheimers-disease-radiodiagnostic-mk-6240

4. Lantheus announces FDA acceptance of New Drug Application for MK-6240, a PET imaging agent targeting tau in Alzheimer disease. Press release. October 28, 2025. Accessed August 13, 2026. https://lantheusholdings.gcs-web.com/news-releases/news-release-details/lantheus-announces-fda-acceptance-new-drug-application-mk-6240