TNF Antagonist

Monitoring the concentration of TNF antagonist drugs and detecting the development of anti-drug antibodies (ADA) enables physicians to optimize patient treatment over time. The test results help physicians understand underlying causes of suboptimal outcomes, make informed therapy choices, and provide more effective treatment to their patients. The use of TNF antagonist has revolutionized the treatment of patients with several non-infectious inflammatory disorders, including Crohn disease and ulcerative colitis.

There are different approaches to manage patients with treatment failure to TNF antagonists; one approach is to monitor drug levels and anti-drug antibodies. A new guideline from the American Gastroenterological Association on therapeutic drug monitoring in inflammatory bowel disease recommends that physicians should perform reactive therapeutic drug monitoring to guide changes in TNF antagonist therapy.

Current methods for ADA detection are complicated by the fact that most TNF antagonist are antibodies and by the complexity of measuring antibodies against antibodies in non-functional binding assays. More importantly, all non-ARUP methods fail to differentiate binding from neutralizing ADA.

ARUP’s TNF antagonist activity and neutralizing antibody assays are cell-based bioassays that measure the ability of a drug to inhibit TNF. The assays also detect the presence of antibodies that neutralize drug activity. Emergence of these neutralizing antibodies in a patient leads to treatment failure. Other methods detect anti-drug antibodies that bind to the drug, but unlike ARUP’s assays, these methods are not able to distinguish whether the antibodies neutralize drug activity or not.