Can a Blood Test Predict Treatment Response in RA?

A recent study suggests that laboratory tests may be helpful in predicting which patients with rheumatoid arthritis will respond to disease-modifying anti-rheumatic drugs (DMARDs).1

Common DMARDs include medications such as methotrexate, sulfasalazine, and hydroxychloroquine that are commonly prescribed to reduce disease activity in patients who are newly diagnosed with RA or who have lived with the disease for many years.

Predicting RA treatment response

With so many treatment options available for RA, wouldn’t it be great to know in advance which treatments are most likely to work for an individual patient? So much about RA treatment is experimental, meaning that doctors will try one thing and if that doesn’t work, try something else. Rinse and repeat. This can be very frustrating for the person living with RA. It can also allow the disease to go unchecked before appropriate, effective treatment is found.

In the new study, published in Nature Communications, researchers discuss newly identified biomarkers that suggest whether a person with RA might respond to treatment with DMARDs. Among DMARD therapies, methotrexate is prescribed to the majority (more than 80 percent) of RA patients at some point. Too often, it can take up to six months for a person to know if a prescribed DMARD will work to dampen their disease. As many as 50 percent of patients are resistant to DMARD treatment or develop resistance over time.1

What is a biomarker?

Biomarkers are substances that can be measured — in blood, synovial fluid, spinal fluid, and other body tissues — which indicate something about a disease. An example of a well-known biomarker for RA would be rheumatoid factor (RF). If you have high levels of RF, it is likely that you have RA. However, the absence of RF doesn’t mean that you can’t have RA. Biomarkers are helpful but not definitive when it comes to diagnosing disease.

Certain biomarkers might suggest poor response to treatment

Researchers at Queen Mary University of London have identified certain small molecules produced from essential fatty acids that when measured can predict treatment response to conventional rheumatoid arthritis DMARDs. These molecules can be measured by looking at specialized pro-resolving mediator (SPM) concentrations in the blood plasma of RA patients. Study participants whose plasma SPM concentrations were higher before treatment and continued to be higher after 6 months of treatment proved to be resistant to DMARD therapy.

My experience: Would I respond to treatment?

When I was diagnosed with RA in 2007, I didn’t have many options for treatment. Since I have multiple sclerosis in addition to RA, any of the TNF-blocker therapies are not appropriate due to potential neurological side effects. My rheumatologist immediately prescribed methotrexate, sulfasalazine, and hydroxychloroquine — a combination of DMARDs often called “triple therapy” — to try to get my RA under control.

We didn't know if treatment would work for me

We didn’t know if these medications would work for me or not. My doctor prepped me by letting me know that it would be several weeks if not months before we would know if they were making a positive difference. That’s a long time to not know if you’re doing the best you can in fighting such a devastating disease.

If there had been a simple blood test to help determine whether DMARDs would work for me, it would have taken some of the fear out of the equation. If results from a biomarker test showed that DMARDs were not likely to work well for me, my doctor and I could have discussed other options from the beginning.

Fortunately, I did respond well to methotrexate, but it was never obvious that sulfasalazine or hydroxychloroquine made any difference. After 2.5 years, I switched to Rituxan with great success.

Biomarkers and personalized medicine

Imagine that you are newly diagnosed. You take a simple blood test and discover that methotrexate is not likely to help your RA. You have the opportunity to discuss other options and can avoid spending your first year of RA suffering and waiting for a drug to begin working.

Or perhaps you’ve been on DMARDs for years and the medication seems to have stopped working. It would be great if a biomarker test could confirm that you are not likely to benefit from staying on your current DMARD. You could explore the next level of RA therapies, including biologics or similarly more effective treatments.

Taking the guesswork out of RA treatment

The development of biomarkers to predict treatment response could greatly improve quality of life and clinical care for people living with RA by helping to guide treatment choices and more effectively reduce disease progression and disability. At a minimum, it could certainly take away some of the stress and guesswork out of choosing an RA treatment when living with the disease.

Be well,
Lisa

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