RA Biomarker Identified

Orthopaedics This Week—February 2, 2010

Narrowing down which patients will benefit…Investigators, led by researchers at Hospital for Special Surgery (HSS) in collaboration with rheumatologists at University of Southern California, have identified a biomarker that could help doctors select patients with rheumatoid arthritis (RA) who will benefit from therapy with TNF-antagonist drugs.

“While our study was performed on a relatively small group of patients and will need to be confirmed in a larger cohort, the data are promising and may be clinically significant for the medical management of patients,” said Mary K. Crow, M.D., in the news release. Dr. Crow, Director of Rheumatology Research and Co-Director of the Mary Kirkland Center for Lupus Research at Hospital for Special Surgery, added, “Treatment with these drugs is very expensive; the drugs can cost around $16,000 or so per year. If you are going to use them, you would like to know that they are likely to work in your patient.” Well-known TNF-antagonists include Humira, Remicade, and Enbrel.

The study involved three cohorts: patients who had RA and received a TNF antagonist, arthritis patients who received no drug, and healthy volunteers. Doctors used a tool commonly employed to gauge the severity of arthritis—the Disease Activity Score in 28 joints—to deem whether patients had a moderate, good, or no response to the drug.

Findings? Patients with higher baseline levels of type I IFN were more likely to respond to therapy with TNF antagonists. Patients who had an increased IFN-beta/alpha ratio, meaning they had more IFN-beta, were also more likely to respond to therapy. They also observed significantly higher baseline levels of IL-1Ra in plasma samples from good responders as compared with those from nonresponders or moderate responders.

“We have drawn attention to a potential biomarker that, if our results are supported by additional future studies in other patient populations, might provide a tool to predict who might be a responder to this class of biologic rheumatoid arthritis therapies, the TNF antagonists, and who might be less likely to be a responder,” Dr. Crow said in the news release. “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.”

Read the full story at ryortho.com.