Demystifying Biomarkers for Lewy Body Dementia

Keith Fargo, PhD, Lewy Body Dementia Association Director of Scientific Initiatives

Have you heard about biomarkers but are unsure what they are? Or maybe you know what they are but don’t know how they are used in medical research and care. You are not alone. The term “biomarker” is unfamiliar to most people. But chances are you will recognize several common medical tests that are in fact biomarkers. These include tests like cholesterol levels for heart disease or blood sugar levels for diabetes. Vital signs like blood pressure, weight, and temperature are also biomarkers. Simply put, a biomarker is something that can be measured about a person’s body that may indicate the presence or absence of a disease, or the progression of a disease process.

Common biomarkers like vital signs and cholesterol tests are in widespread use in doctors’ offices to guide treatment decisions. For example, a doctor may recommend starting or stopping a medication based on your blood pressure. But biomarkers are typically used first in research. In a scientific setting, researchers use biomarkers to study how a disease progresses over time and how it responds to experimental treatments. Biomarkers are extraordinarily valuable in this context. Among other things, they allow researchers to ensure clinical trials include people who are likely to benefit from the drug being studied and track whether the experimental treatment is better than a placebo.

The past decade has brought incredible progress in biomarkers for Lewy body dementia. In the research setting, there are now biomarkers that measure the amount of “bad” alpha-synuclein (the protein that makes up Lewy bodies) in the skin and in the fluid that surrounds the brain and spinal cord. EEG patterns during REM sleep can indicate the presence of REM sleep behavior disorder (RBD), which can appear many years before other symptoms of LBD. Various kinds of brain imaging such as MRI also provide clues about LBD. In fact, one imaging biomarker called DaTscan is now approved by the U.S. FDA for diagnostic use in dementia with Lewy bodies (DLB, one of the two main forms of LBD). Researchers are also working on a method to image Lewy bodies in the brain, as current imaging methods show indirect evidence of their effects rather than direct evidence of their presence. When this becomes reality, most researchers expect it will be a major breakthrough in the race to develop effective therapies to treat or prevent LBD.

As biomarkers for Lewy body dementia continue to be refined and prove their worth, they are being added to most new large clinical studies of LBD. For example, both the SHIMMER trial and the newly funded trial of neflamapimod use biomarkers. You can find information about other ongoing clinical trials, many of which use biomarkers, by visiting LBDA’s clinical studies webpage.