Robb, W. Hudson; Kaur, Gurkiran; Huang, Steven; Martinez, Felipe; Nguyen, Ba; Shin, Clifford H.; Yang, Ming; Conyers, Christopher T.; Grilli, Christopher B.; Upjohn, David P.; Ortega, Victor E.; Hohman, Timothy J.; Keegan, Richard M.; Parent, Ephraim E.; Cogswell, Petrice M.; Graff-Radford, Jonathan; Johnson, Derek R.; Ramanan, Vijay K.; Koran, Mary Ellen (2026).听.听Alzheimer’s and Dementia, 22(4), e71343.听
New treatments for Alzheimer鈥檚 disease that target聽amyloid-beta (A尾)鈥攁 protein that builds up in the brain鈥攁re changing how the disease is diagnosed and managed. This study examined real-world data from Mayo Clinic health records (2019鈥�2025) to see how testing and treatment patterns have shifted with the introduction of a drug called聽lecanemab, which is given by infusion.
After insurance coverage expanded, use of lecanemab increased rapidly. At the same time, there were notable changes in how patients are tested: traditional methods like聽cerebrospinal fluid (CSF) testing聽declined, while blood-based tests鈥攅specially聽plasma p-tau217聽(a marker linked to Alzheimer鈥檚-related brain changes)鈥攔ose sharply. Brain scans using聽PET imaging聽to detect amyloid also increased. All patients who received lecanemab were confirmed to have amyloid buildup through PET or CSF testing.
The study also found that women were more likely to test positive for amyloid across different testing methods. Genetic testing showed that many patients carried the聽APOE-蔚4 variant, a gene associated with higher Alzheimer鈥檚 risk, but those with two copies of this variant were less likely to start lecanemab treatment. Overall, the findings show that the arrival of anti-amyloid therapies is rapidly reshaping both diagnostic approaches and treatment use in real-world clinical care.
FIGURE 1
Regulatory milestones of Alzheimer’s disease biomarkers and treatments from 2012 through 2025. A尾, amyloid-beta; AD, Alzheimer’s disease; CMS, Centers for Medicare & Medicaid Services; CSF, cerebrospinal fluid; PET, positron emission tomography; pTau, phosphorylated tau.