Cheifetz, Adam S.

Therapeutic drug monitoring (TDM) of biologics is a rapidly evolving field. We aimed to provide a consensus statement regarding the clinical utility of TDM for biologics in inflammatory bowel disease (IBD). A modified Delphi method was applied to develop consensus statements. A comprehensive literature review was performed regarding TDM of biologic therapies in IBD, and 45 statements were subsequently formulated on the potential application of TDM in IBD. The statements, along with literature, were then presented to a panel of 10 gastroenterologists with expertise in IBD and TDM who anonymously rated them on a scale of 1–10 (1 = strongly disagree and 10 = strongly agree). An expert consensus development meeting was held virtually to review, discuss, refine, and reformulate statements that did not meet criteria for agreement or that were ambiguous. During the meeting, additional statements were proposed. Panelists then confidentially revoted, and statements rated ≥7 by 80% or more of the participants were accepted. During the virtual meeting, 8 statements were reworded, 7 new statements were proposed, and 19 statements were rerated. Consensus was finally reached in 48/49 statements. The panel agreed that reactive TDM should be used for all biologics for both primary nonresponse and secondary loss of response. It was recommended that treatment discontinuation should not be considered for infliximab or adalimumab until a drug concentration of at least 10–15 μg/mL was achieved. Consensus was also achieved regarding the utility of proactive TDM for anti–tumor necrosis factor therapy. It was recommended to perform proactive TDM after induction and at least once during maintenance. Consensus was achieved in most cases regarding the utility of TDM of biologics in IBD, specifically for reactive and proactive TDM of anti–tumor necrosis factors.

INTRODUCTION: Treatment options for patients with moderate-severe ulcerative colitis (UC) are increasing. The appropriateness of their use in mild-moderate UC is less clear, as is the role of surgical intervention. Our aim was to define the appropriateness of therapeutic options in a range of clinical scenarios in mild-moderate UC METHODS: We applied the RAND/UCLA Appropriateness Method to rate appropriateness of treatment choices in patients with mild-moderate UC; severe disease (likely to need hospitalization or surgery within 2 weeks) was excluded. A literature review was presented to the BRIDGe group, a panel of 13 IBD specialists, as well as 1 external IBD expert and 2 IBD surgical experts. 12 chapters were constructed including failed 5-ASA, steroid or thiopurine therapy, and primary/secondary non-response to biologics or tofacitinib. Scenarios were also divided by disease extent (proctitis vs more extensive) and activity (mild vs moderate) creating 260 scenarios in all. Panellists used a modified Delphi method to anonymously rate the appropriateness of a therapy on a 1-9 scale (1-3 not appropriate, 4-6 uncertain, 7-9 appropriate). Disagreement was assessed using a validated index (DI) and was defined as a DI > 1. The panellists then convened in person to discuss areas of disagreement, followed by a second round of rating. Scenarios rated a median of 7 or higher were deemed appropriate and those rated 3 or lower were deemed inappropriate. Scenarios rated 4-6 were considered uncertain, as were any with a DI > 1 RESULTS: Appropriateness was agreed in 131 and inappropriateness in 47 scenarios. Greatest disagreement was around the use of thiopurines, but no scenario had a DI > 1. There were 82 scenarios were rated uncertain. Biologics and tofacitinib were more likely to be rated appropriate for treatment resistance and greater disease activity; disease extent less likely to influence decision making. Surgery was felt to be appropriate in 8 scenarios, generally in more extensive and active disease that had failed to respond to medical therapy. Surgery was felt to be inappropriate in 16 scenarios and was uncertain in 24 CONCLUSION: Although there was little disagreement amongst an expert panel of IBD physicians and surgeons, there remained uncertainty about the use of medical and surgical therapy in nearly one third of situations in patients with mild-moderate UC. These results could be used to guide the design of clinical trials for these patient groups in order to guide best practice.