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 biologic 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 of therapeutic drug monitoring (TDM) for various clinical scenarios. We applied a modified Delphi panel approach, which is an iterative, evidence-based process that combines the best available scientific data with the collective judgment of IBD and TDM specialists. A comprehensive, structured literature review was conducted on the topic of TDM in patients with IBD for all approved biologic therapies. This review was presented to a panel of IBD and TDM specialists 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 TDM. Panelists used a modified Delphi method to anonymously rate 28 statements describing when and how to apply TDM in clinical practice using a 1- 10 scale (1=strongly disagree, 10=strongly agree). Statements were accepted if 80% or more of the participants agreed with a score ≥7. If less than 80% of the panelists agreed with a score ≥7, statements were discussed and revised based on the available evidence followed by a second round of voting. Utilization of TDM and interpretation of biologic drug concentrations and anti-drug antibody titers 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 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 4 permutations of < or ≥ of a clinically relevant drug concentration threshold and high/low or undetectable anti-drug antibodies. A web-based tool was then developed allowing easy access and display of how to respond to various permutations of drug concentrations and anti-drug antibody titers in the setting of specific clinical settings.

To view the full manuscript of how the Biologic Therapy Optimizer was developed, click here.


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.