Review article: Optimisation of biologic (monoclonal antibody) therapeutic response in inflammatory bowel disease

Background: There are a plethora of therapeutic options for the management of inflammatory bowel disease (IBD). Despite this, clinical outcomes with standard dosing often fall short of established targets. While efforts centre on developing novel therapies, there is an ongoing need to optimise the use of existing agents. Aims: To focus on strategies to optimise response to biologic (monoclonal antibody) therapies in IBD, including use of therapeutic drug monitoring (TDM). Methods: An extensive review of the published literature. Results: TDM is a strategy aimed at enhancing the effectiveness of drugs with variable exposure-response relationships by measuring serum concentrations of biologic therapies and detecting neutralising antibodies. Reactive TDM is performed when therapeutic goals have not been achieved. Tumour necrosis factor alpha (TNF) inhibitors are the treatment class most frequently associated with immunogenicity and loss of response. Immunogenicity can be reduced through avoidance of low serum drug concentrations by dose optimisation or use of concomitant immunomodulator therapy. Subtherapeutic dosing in the absence of antidrug antibodies is best managed by dose escalation or dose interval reduction. Persistent neutralising drug antibodies necessitate switching to an alternative therapy. Proactively ensuring adequate serum trough levels might help sustain treatment durability and prevent loss of response. Newer non-TNF inhibitors demonstrate less robust exposure-response relationships, and TDM may not prove as beneficial. Conclusions: In the treat-to-target paradigm of IBD treatment, optimising treatment effect with dose optimisation, which may involve strategies including TDM, increases the likelihood of achieving clinical remission and may accomplish deeper levels of remission beyond symptom control.