[A New Path for Dementia Treatment] ③ Challenges of False Positives and Reimbursement Amid Surging Demand

One in Four People in Their 70s at High Risk for False Positives

Long Waits Remain for Confirmatory PET Scans

MRI Monitoring Costs Remain a Burden Despite Regulatory Recommendations

Editor's NoteA revolutionary change in Alzheimer's disease treatment is imminent. The expensive brain imaging tests that used to require a two-month wait may soon be replaced by a simple blood test, and intravenous treatments that used to tie patients to a hospital for an hour every two weeks could be substituted by a self-injection that takes only 15 seconds. As the physical, spatial, and time constraints of diagnosis and treatment collapse, those eligible for treatment will expand from dementia patients to “ordinary people who are asymptomatic but at risk.” However, there is still no infrastructure to support testing at this scale, nor criteria to filter out false positives, nor a reimbursement system to share costs. The Asia Business Daily examines the paradigm shift in dementia treatment and discusses how best to prepare for it.

① The Treatment Landscape Is Changing: Two Months for Testing, One Hour for Infusion

② Blood Tests and SC Formulations Open Up 'Opportunities' Even for K-Bio

③ Soaring Demand Expected, but 'False Positives and Reimbursement' Remain Challenges

With the sequential introduction of blood tests, the threshold to Alzheimer's disease testing is lowered, but diagnosis cannot rely on tests alone. Patients with high levels must still be confirmed with a positron emission tomography (PET) scan. This has raised concerns that if capacity for confirmatory tests and criteria for filtering out false positives are not established alongside growing demand, the advantages of early diagnosis may be offset.

According to the medical community on September 9, the blood tests soon to be introduced will play different roles depending on their accuracy. Kihyung Park, president of the Korean Dementia Association and neurology professor at Gil Medical Center, said, “The phosphorylated tau protein (p-tau181) test can fairly reliably rule out Alzheimer's disease, while p-tau217 has reached a level where a positive result is highly likely to also be positive in a PET scan,” adding, “Ultimately, PET scans are necessary for definitive confirmation.”

Blood Test Followed by PET...The Burden of Confirmatory Testing

PET scan capacity has already reached its limit. For example, at Korea University Guro Hospital's Alzheimer's Prevention Center, about 80 to 100 scans are performed per month, with a waiting time of about two months. Since amyloid PET scans use the same equipment as cancer metastasis tests, major hospitals where many cancer patients gather may require a wait of four to five months. Currently, only patients with cognitive decline who visit neurology clinics receive this test. If blood tests become available in routine health check-ups and local clinics, the target population for confirmatory tests will expand to older adults without symptoms.

This is where the hurdle of false positives arises. A false positive refers to a test result indicating disease when the patient is actually healthy. For instance, patients with chronic kidney disease may have elevated blood p-tau levels due to impaired kidney metabolism, even without amyloid accumulation in the brain. Blood values can also fluctuate due to anemia or low body weight. The key issue is that these conditions overlap with typical test populations. According to Korea Disease Control and Prevention Agency health statistics, the prevalence of chronic kidney disease among those in their 70s or older was 25.1 percent in 2023. This means that one in four people in the tested age group is at risk for a false positive.

An illustration depicting an elderly woman suffering from Alzheimer's disease struggling with memory loss. AI-generated image

There are also concerns that research results may overestimate real-world performance. Seonghun Kang, director of the Alzheimer's Prevention Center at Korea University Guro Hospital, pointed out, “Research cohorts are recruited based on registration criteria that exclude patients with severe diseases, so participants tend to be healthier, whereas real clinical patients often have multiple comorbidities.” This means that the accuracy reported in studies may not translate directly to clinical practice, so interpretation standards need to reflect this.

Determining who should interpret results may also be problematic. While blood tests are expected to spread rapidly—since even local clinics without their own labs can send samples to outside labs—the impact of kidney function or body weight on test results is not easy to assess in everyday clinical settings.

Cost concerns remain as well. Every step, from diagnosis to treatment, is not covered by insurance. A blood test costs 100,000 to 300,000 won, an amyloid PET scan exceeds 1 million won, and the medication Leqembi costs 1 to 1.5 million won per session, requiring 38 to 39 infusions for a total of 40 to 50 million won. In the United States and Japan, these medications are covered by insurance.

Some in the field argue that insurance should first cover monitoring MRI scans rather than drug costs. Currently, the Ministry of Food and Drug Safety recommends an MRI scan to check for brain swelling or bleeding during amyloid-targeting therapy, but this scan costs 300,000 to 500,000 won per session, also uncovered by insurance. Educational counseling fees—applicable to diabetes, hypertension, and cancer treatment—are not available for Alzheimer's disease, meaning a preliminary interview of 30 to 40 minutes before first treatment is not compensated. A university hospital neurology professor commented, “Since MRI scans are done based on recommendations from the regulatory agency, we need to consider insurance coverage. Having proper reimbursement codes would allow hospitals to expand related infrastructure.”

The need to establish such standards and reimbursement systems is urgent because the population requiring management is set to grow dramatically. Results from clinical trials of people with normal cognitive function but amyloid buildup in the brain will be released at the end of next year. If efficacy is confirmed, the treatment population will shift from symptomatic to asymptomatic individuals.

President Park believes the success of this transition depends on blood tests. Detecting asymptomatic patients requires a large-scale screening method, which would be impossible with only expensive PET scans. He noted, “If the tests are commercialized and treatments for pre-symptomatic stages are approved, we will move into a preventive stage that stops disease progression before symptoms appear—heralding a new chapter in dementia therapy.” He added that proactively anticipating and addressing the issues and gaps that may arise during this process is essential for this transition to be meaningful.

This content was produced with the assistance of AI translation services.