BEDFORD, Mass. — Enigma Biomedical USA announced that the U.S. Food and Drug Administration has accepted the New Drug Application for MK-6240 (florquinitau F-18), a Tau PET radiodiagnostic designed for Alzheimer’s disease. The drug, which previously received Fast Track designation, targets tau neurofibrillary tangles (NFTs)—a defining hallmark of Alzheimer’s pathology. The FDA has set a Prescription Drug User Fee Act (PDUFA) action date of August 13, 2026.
In April 2025, Lantheus reported that MK-6240 met its co-primary endpoints in two pivotal studies, paving the way for the NDA filing in the third quarter of 2025. Lantheus acquired the rights to MK-6240 in 2023 and partnered with the Enigma Biomedical team for its continued development.
“EB USA is extremely excited about NDA acceptance of the MK-6240 filing and congratulate our partners at Lantheus for this significant accomplishment,” said Rick Hiatt, President and CEO of Enigma Biomedical USA. “This milestone is an important step in our committed journey to address critical unmet needs in neurodegenerative disease as well as providing tools and technologies to support the development of disease-modifying therapies.”
“We are pleased the FDA accepted our NDA for MK-6240,” said Brian Markison, CEO of Lantheus. “By enabling early and accurate identification of tau accumulation, MK-6240 has the potential to enhance diagnostic confidence, personalize patient care, and, through ongoing monitoring, transform our understanding of disease progression. We are deeply grateful for the continued support and expertise of the Enigma team, whose contributions have been instrumental to the development of MK-6240.”
MK-6240 (florquinitau F-18) is designed to bind aggregated tau protein in the form of NFTs, a critical marker of Alzheimer’s and related neurodegenerative diseases. The compound has demonstrated high affinity for tau and minimal off-target binding in preclinical and clinical studies. Acquired by Lantheus in 2023, MK-6240 has Fast Track designation and is being used in nearly 100 active clinical trials. The agent is expected to advance early detection, patient staging, therapy selection, and disease monitoring, potentially enabling tau to serve as a surrogate endpoint for treatment efficacy.
