Rheumatologists may one day be able to test in advance which patients with rheumatoid arthritis will benefit from expensive biological response modifier TNF-antagonist drugs - or biologics - and which will not. This is because a new study has indicated that RA patients with the most elevated type 1 interferon levels tend to be those who responded most favorably to TNF-antagonist drugs.
Mary K. Crow, MD, Physician-in-Chief and Joseph P. Routh Chair in Rheumatic Diseases in Medicine, led this initial study for HSS, in conjunction with University of Southern California. A 35-patient sample was divided into three groups: RA patients who received a TNF-antagonist drug, RA patients who got no drug, and healthy volunteers.
Using the Disease Activity Score in 28 joints, the patients were treated, then evaluated to determine whether they had a moderate, good, or no response to the drug. Comparing the 3 groups, higher levels of type 1 interferon prior to treatment were found in the blood of patients who benefited most. Lower levels were associated with lower response.
Patients who had an increased IFN-beta/alpha ratio - meaning they had more IFN-beta - were also more likely to respond to TNF-antagonist therapy. Another indication of good response was significantly higher baseline levels of IL-1 receptor antagonist in plasma samples when compared with nonresponsive or moderate responders. If wider studies prove consistent with these promising early findings, the results could represent a new tool for improved management of patients with rheumatoid arthritis.
Knowing whether a TNF-antagonist biologic will help a patient’s rheumatoid arthritis can save time, money, and patients investing emotionally in the possibility of relief. “Treatment with these drugs is very expensive; the drugs can cost $16,000 or so per year," says Dr. Crow. "If you are going to use them, you would like to know that they are likely to work in your patient.”
Dr. Crow adds, “For those who demonstrate low levels of blood interferon activity, that information might be useful to guide patients to alternative treatments that might be more likely to work for them.”