Biologic Therapy Optimizer

About the BRIDGe group

BRIDGe was formed in 2006 and is composed of a group of gastroenterologists who are all experts in IBD-patient care and focused on patient-centered clinical IBD research. Please visit our website at

Methods to create the BRIDGe Biologic Therapy Optimizer

The commercial availability of drug concentration and antibody testing for anti-TNF therapy promises optimized drug dosing and informed therapeutic decision-making for patients with inflammatory bowel disease (IBD). However, there is no consensus on how to interpret the results for various clinical scenarios. We applied the RAND/UCLA Appropriateness Method toward establishing the appropriateness of how to act upon results of anti-TNF concentration and antibody testing. The RAND/UCLA appropriateness method employs a modified Delphi panel approach, which is an iterative, evidence-based process that combines the best available scientific data with the collective judgment of experts to determine the “appropriateness” of processes of care in medicine.

METHODS: A comprehensive, structured literature review was conducted on the topic of drug concentration and anti-drug antibodies in patients with Crohn’s disease (CD) and ulcerative colitis (UC) for all approved anti-TNF therapies. This review was presented to an expert panel including clinician and pharmacist experts who have published on the topic, and the Building Research in Inflammatory Bowel Disease Globally (BRIDGe) group, a globally diverse panel of 13 gastroenterologists experienced in IBD treatment and therapeutic drug monitoring. A total of 143 clinical scenarios addressed the appropriateness of various strategies in response to test results. Panelists used a modified Delphi method to anonymously rate each scenario through a web-based questionnaire, and then met in-person to discuss and anonymously re-rate appropriateness on a 1-9 scale (1-3 inappropriate, 4-6 uncertain, 7-9 appropriate). Disagreement was assessed using a validated index.

RESULTS: Interpretation of anti-TNF drug concentration and antibody levels was rated based on different clinical scenarios including at the end of induction therapy in primary nonresponders, at the end of induction in responders, in secondary nonresponders, and at a time point during the first year of maintenance therapy. Panelists established the appropriateness of various clinical management options including changing therapy within-class, switching out of class, adjusting drug dose/interval, adding/adjusting concomitant immunomodulators, and “doing nothing” for each of 6 permutations of high/low drug concentration and high/low/undetectable antibody levels. A web-based tool was then developed allowing easy access and display of how to respond to various permutations of drug concentration and antibody level in the setting of specific clinical settings. For every scenario (clinical, drug and antibody concentration) this tool will give a summary of actions that are appropriate, inappropriate, or of uncertain benefit or harm.


This algorithm shows the results of an independent BRIDGe research project, and is not intended nor recommended as a substitute for medical advice or treatment. Always seek the advice of a physician or other qualified health care professional regarding any medical questions or conditions.