Predicting Which RA Patients Won’t Respond to Biologic Drugs

Researchers from the UK have found a way to predict which rheumatoid arthritis (RA) patients will not respond to biologic drugs. The team, from the University of Manchester, was led by Dr. Meghna Jani of the Centre for Musculoskeletal Research.

According to the July 3, 2015 news release, “In order to detect the antibodies and to measure the drug levels in the bloodstream, previously it was thought that the testing to detect the anti-drug antibodies and measure drug levels in the bloodstream, would only be helpful if performed immediately before the next dose of drug was due, when the drug levels are at their lowest in the body. This approach can be difficult to arrange in a clinical setting, as patients take the drugs on different days and at different times.”

“There were 311 patients included in the study, who provided blood samples for testing at three, six and 12 months after starting two different types of biologic drugs, adalimumab. The research revealed that a total of 25% of patients on adalimumab developed antibodies, but none were found in the patients using etanercept.”

“The researchers also found that higher doses of methotrexate, a drug often given together with the biologic treatment, was associated with lower levels of drug antibodies, suggesting that patients should be encouraged to continue methotrexate at the highest dose they can tolerate, to reduce the risk of developing anti-drug antibodies.”

Professor Anne Barton, a consultant rheumatologist at Central Manchester University Hospitals NHS Foundation Trust and Director of the Centre for Musculoskeletal Research at The University of Manchester explained: “The next step will be to explore whether it is cost-effective to use these tests routinely in clinical practice, so that we can adjust treatments in those patients with low drug levels and anti-drug antibodies.”

Dr. Jani told OTW, “We found even random adalimumab drug levels can provide valuable predictive information as early as three months, on future response to treatment at 12 months. The factors strongly associated with low drug levels were drug antibody formation, a high body mass index and whether or not the patient took the drug as advised (adherence).”

“Our eventual aim as rheumatologists is to get the treatment right the first time in our rheumatoid arthritis patients. If we can use these markers to predict early which patients will fail biologic treatment, we could facilitate a shift to more effective alternative therapy sooner. By doing so, we may prevent long-term joint damage that leads to disability, however this needs to be tested over a longer-term studies in the future.”