Alzheimer’s disease (AD) is the most common form of dementia and is incurable, degenerative and irreversible. It affects more than 5 million people in the United States, a number that is expected to exceed 16 million by 2050. Neuropsychological tests, such as the mini-mental state examination (MMSE), are commonly used to diagnose patients. However, cognitive impairment may be due to another disease, not Alzheimer’s.  There remains an unmet need to be able to differentiate between different forms of dementia. 

Imaging biomarkers are providing new diagnostic tools. One of the seminal biomarkers for Alzheimer’s disease is Pittsburgh compound B (PiB).  PiB is a fluorescent analog of thioflavin T; it is used in combination with Positron Emission Tomography (PET) scans to image beta-amyloid plaques in the brains of Alzheimer’s disease patients. Beta-amyloid has been proven to be a hallmark of Alzheimer’s disease and is accumulated in the brain in the very early course of the disease.  

PiB PET studies have shown that they can improve the accuracy of dementia diagnosis in the early stages of the disease by measuring disease-related amyloid accumulation. 

Companies have developed imaging biomarkers for Alzheimer’s disease diagnosis.  Bayer has developed florbetaben (BAY 94-9172), an 18F radiolabeled tracer that binds to beta-amyloid in phase III clinical trials.  Avid Radiopharmaceuticals is a company purely focused on new imaging biomarkers with AV-45 in Phase III development. 

What are your thoughts on using biomarkers and PET in the early diagnosis of Alzheimer’s disease?