Therapeutic drug monitoring (TDM), which involves measurement of drug or active metabolite levels and anti-drug antibodies, is a promising strategy that can be used to optimize inflammatory bowel disease therapeutics. It is based on the premise that there is a relationship between drug exposure and outcomes, and that considerable inter-individual variability exists in how patients metabolize the drug (pharmacokinetics) and the magnitude and duration of response to therapy (pharmacodynamics). Therefore, the American Gastroenterological Association has prioritized clinical guidelines on the role of TDM in the management of inflammatory bowel disease. To inform these clinical guidelines, this technical review was developed in accordance with the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) framework for interventional and prognostic studies, and focused on the application of TDM for biologic therapy, specifically anti-tumor necrosis factor−α agents, and for thiopurines. Focused questions address the benefits and risks of a strategy of reactive TDM (in patients with active inflammatory bowel disease) to guide treatment changes compared with empiric treatment changes, and the benefits and risks of a strategy of routine proactive TDM (during routine clinical care in patients with quiescent disease) compared with no routine TDM. Additionally, the review addresses the benefits and risks of routine measurement of thiopurine methyltransferase enzyme activity or genotype before starting thiopurine therapy compared with empiric weight-based dosing and explores the performance of different trough drug concentrations for anti−tumor necrosis factor agents and thiopurines to inform clinical decision making when applying TDM in a reactive setting. Due to a paucity of data, this review does not address the role of TDM for more recently approved biologic agents, such as vedolizumab or ustekinumab.

治疗性药物监测（TDM）涉及药物或活性代谢物水平和抗药物抗体的测量，是一种可用于优化炎症性肠病治疗方法的有前途的策略。这是基于这样的前提，即药物暴露与疗效之间存在关联，并且患者之间如何代谢药物（药代动力学）以及对治疗的反应程度和持续时间（药效学）存在很大的个体差异。因此，美国胃肠病学协会已将TDM在炎症性肠病管理中的作用作为临床指南的重点。为了为这些临床指南提供依据，该技术审查是根据GRADE（建议书评估，开发评分，和评估）框架进行干预和预后研究，并重点关注TDM在生物治疗中的应用，特别是抗肿瘤坏死因子-α药物和硫嘌呤的应用。有针对性的问题解决了反应性TDM策略（在活动性炎症性肠病患者中）指导经验变化与经验治疗变化相比的益处和风险，以及常规主动性TDM策略（在常规临床护理过程中）的益处和风险。静态疾病患者）与没有常规TDM的患者进行比较。此外，综述探讨了与基于体重的剂量给药相比，开始进行硫嘌呤治疗之前常规测量硫嘌呤甲基转移酶活性或基因型的益处和风险，并探讨了不同浓度药物对抗肿瘤坏死因子药物和硫嘌呤的影响，以指导临床决策在无功设置中应用TDM时进行制作。由于缺乏数据，该评价未解决TDM对最近批准的生物制剂（如维多珠单抗或乌斯他单抗）的作用。