Biomarkers are chemicals or components of the immune system that can be used to mark or define the level of inflammation or disease, or the responsiveness of a patient to a specific medication. Let me give you some examples. Biomarkers for a cardiovascular disease would be lipids, cholesterol, or blood pressure. Biomarkers for thyroid disease would be thyroid function tests.
Biomarkers are very important for people with arthritis, such as rheumatoid arthritis. They can define the level of the activity of the disease; if someone is not doing well and you have a sensitive way to measure disease, you may then want to change the therapy to improve the patient's outcome.
In that context, it is essential that we find biomarkers that actually predict who will respond to a given biologic drug. For example, when you have a urinary tract infection, your urine specimen is cultured and analyzed so that your physician can know which antibiotic will work for the specific bacteria. That result is 100% accurate. If you use that antibiotic, it will control the infection because we know exactly what the sensitivities of the bacteria are.
Searching for a Gram Stain for Inflammatory Joint Disorders
Right now we do not have that sensitivity when we use biologics for treatment of inflammatory joint disorders. Treatment is very hit-or-miss. Thus, a patient may very well be on one anti-TNF agent for 3 months, on another for 3 months, and on a third for 3 more months, with no response, amounting to almost a year of treatment that is incorrect for that patient. Imagine the amount of damage that can occur in that time and the waste of money.
Specific types of biomarkers are now being developed so you can form a similar concept to an antibiotic Gram stain. Basically, you would be able to define whether someone will respond to a specific medicine, just as you would find the appropriate antibiotic for a patient with an infection.
At the 2014 American College of Rheumatology meeting in November, I heard reports of impressive biomarkers, and various ratios of particular cytokines that can actually show who will respond to an anti-TNF and who will not. Various genetic profiles also are being used. There is a real need for us to be able to predict who will respond to what medication.
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Cite this: The Role of Biomarkers in Rheumatology - Medscape - Dec 19, 2014.