AS Cheifetz et al. Am J Gastroenterol 2021;116: 2014-2025. A Comprehensive Literature Review and Expert Consensus Statement on Therapeutic Drug Monitoring of Biologics in Inflammatory Bowel Disease (published online August 13, 2021)

Key recommendations:

• 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 mg/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.
• More data are needed with regard to proactive TDM for biologics other than anti-TNF agents
• There are no differences in interpreting TDM between originator biologics and biosimilars
• When considering switching within drug class in case of secondary loss of response to a first anti-TNF drug because of the development of antidrug antibodies, an immunomodulator should be added to a subsequent anti-TNF therapy
• Low-titer antidrug antibodies can be overcome by treatment optimization (dose escalation, dose interval shortening, and/or addition of an immunomodulator)

My take: This article should help support the practice of proactive TDM and discourage stopping anti-TNF agents until an adequate therapeutic level is achieved.

Related blog posts:

• Can Therapeutic Drug Monitoring with Monotherapy Achieve Similar Results as Combination Therapy?
• Real-World Experience with Proactive Therapeutic Drug Monitoring in Inflammatory Bowel Disease
• Here’s The Proof That Proactive Drug Monitoring Improves Outcomes in Children With Crohn’s Disease
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