FDA approves New Brain Imaging Agent For Alzheimer's Assessment

Doctors evaluating patients for Alzheimer's disease now have a new tool to look directly at one of the proteins closely tied to the disease and how it progresses.

The U.S. Food and Drug Administration has approved Tauklarify, an imaging agent that lights up a protein called tau inside the brain during a PET scan, Lantheus Holdings, the company that makes it, announced on August 14, 2026.

Tauklarify, known chemically as florquinitau F 18 injection, is not a treatment.

It is a radioactive dye, injected into a patient's bloodstream before a positron emission tomography scan, a type of imaging test that uses small amounts of a radioactive tracer to show activity inside the body rather than just its structure.

The dye attaches itself to tau tangles in the brain, making them visible on the scan.

What Tau Actually Is, and Why Doctors Want to See It

Alzheimer's disease is linked to two abnormal proteins that build up in the brain over time: beta-amyloid and tau.

Amyloid tends to accumulate first, often years before a person shows any symptoms.

Tau builds up later, and its spread through the brain lines up much more closely with how severe a patient's memory and thinking problems become.

That difference matters for diagnosis.

A brain that shows amyloid but very little tau may belong to someone who is at risk but not yet significantly impaired.

A brain with substantial tau spread often points to more advanced disease. Until now, doctors evaluating Alzheimer's in the United States have had one FDA-approved tau scan available, a product called Tauvid, approved in 2020. Tauklarify becomes the second.

How Well the Scan Performed

Tauklarify's approval rests on two blinded read studies in which independent doctors, working separately and without knowing how their colleagues had scored the same images, reviewed PET scans from more than 500 people who took part in three clinical trials.

The participants ranged from cognitively healthy older adults to people with mild cognitive impairment and mild Alzheimer's dementia, covering the disease from its earliest stages onward, according to Lantheus.

In the first study, of 279 subjects, the doctors agreed with each other on a positive tau result between 80 and 88 percent of the time, and agreed on a negative result between 98 and 99 percent of the time.

In the second study, of 338 subjects, agreement on positive results ranged from 68 to 82 percent, and agreement on negative results ranged from 93 to 99 percent.

Both studies met the success criteria the FDA had set in advance.

Safety was assessed in 1,734 people who received the injection.

The most commonly reported side effects were headache, affecting about 7 in 1,000 patients, along with smaller numbers reporting nausea, discomfort at the injection site, dizziness or abdominal discomfort, each in roughly 1 or 2 out of every 1,000 patients, according to Lantheus.

What a Scan Result Does and Does Not Tell a Patient

A Tauklarify scan is not a stand-alone diagnosis.

Lantheus said a positive result does not necessarily confirm that a patient has tau pathology, and a negative result does not rule it out.

The scan is meant to be one piece of evidence a doctor weighs alongside cognitive testing and a patient's medical history, and clinicians may also consider amyloid PET or other biomarkers where available, not a replacement for that broader evaluation.

Mary Anne Heino, executive chairperson and interim chief executive officer of Lantheus, said the approval reflects a shift in how clinicians think about the disease.

"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," Heino said in the company's August 14, 2026 announcement.

Keith Johnson, professor of neurology and radiology at Massachusetts General Hospital and Harvard Medical School, said the tool has value beyond any single patient's diagnosis.

"For clinicians and researchers, tau PET imaging is an important tool for identifying tau pathology in the brain and advancing our understanding of Alzheimer's disease," Johnson said in the same announcement.

A Small Market, a Bigger Disease Burden

Commercially, Tauklarify is entering a narrow space. Tauvid has held the tau-imaging market since 2020, and B.

Riley Securities analyst Yuan Zhi told Reuters the entire market is probably worth less than $100 million a year, with Tauklarify unlikely to bring in more than $50 million annually by 2030.

The disease itself is a far bigger problem than that market size suggests.

More than 7 million people in the United States currently live with Alzheimer's, a figure the Alzheimer's Association projects could approach 13 million by 2050 as the population ages, and Alzheimer's remains the most common cause of dementia worldwide, gradually eroding memory, thinking and the ability to manage daily life.

Why This Also Matters Outside Wealthy Countries

Global dementia cases are projected to roughly triple by 2050, and more than 60 percent of people living with dementia already live in low and middle income countries, a share the World Health Organization expects to rise further by 2050.

Africa is projected to have one of the highest numbers of people living with Alzheimer's and related dementias in the world over the next two decades.

Access to the imaging tools that make a diagnosis like Tauklarify's possible has not kept pace with that burden.

A review published in the journal Alzheimer's & Dementia found that no African country has published research or reported an active clinical trial using PET imaging for Alzheimer's and related dementias, and that only four African countries have conducted any dementia research using MRI at all.

The researchers estimated it would take tens of billions of dollars to build the scanners, radiotracer production and trained staff needed to close that gap.

That means a tool like Tauklarify, however well it performs in the studies that won it FDA approval, is likely to remain out of reach for most patients outside a small number of wealthy health systems for years to come.

Across much of sub-Saharan Africa, limited specialist services, diagnostic imaging and public awareness of dementia already stand between patients and a formal diagnosis of any kind, the World Health Organization has noted, well before a scan like this one becomes a realistic option.

Tauklarify's approval does not change that picture on its own.

What it does is give doctors in health systems that already have PET scanners a second option for looking at tau, adding to a small but growing set of tools aimed at making Alzheimer's diagnosis more precise for the patients who can reach them.