Y-ECCO Literature Review: Neil Chanchlani
Proactive monitoring of adalimumab trough concentration associated with increased clinical remission in children with Crohn's Disease compared with reactive monitoring
Assa A, Matar M, Turner D, Broide E, Weiss B, Ledder O, Guz-Mark A, Rinawi F, Cohen S, Topf-Olivestone C, Shaoul R, Yerushalmi B, Shamir R
Gastroenterology. 2019;157:985–96.e2. doi: 10.1053/j.gastro.2019.06.003
© Neil Chanchlani
Therapeutic drug monitoring (TDM) of the anti-TNF monoclonal antibodies, infliximab and adalimumab, in patients with Inflammatory Bowel Disease is gradually being adopted into routine clinical practice in the United Kingdom  and United States . The aim of TDM, measuring an individual’s drug and anti-drug antibody levels, is to assess compliance, drug metabolism and immunogenicity with a view to guiding adjustments or changes in management in order to improve clinical outcomes1. TDM can be proactive, with routine measurement of drug level and anti-drug antibody regardless of clinical outcome, or reactive, with measurement of drug level and anti-drug antibody in the setting of loss of response . Compared to empirical dosing alone, TDM used reactively, at the time of loss of response to an anti-TNF treatment, improves durability of response and safety and leads to significant cost savings [4,5]. The evidence base supporting proactive over reactive TDM is, however, less clear. Two randomised controlled trials done in adults (TAXIT  and TAILORIX ) did not demonstrate any differences in biological, endoscopic or corticosteroid-free remission between groups, though these trials were limited by methodological limitations and isolating the effect of proactive TDM on defined outcomes was difficult. In contrast, multiple observational studies have concluded that there is less risk of treatment failure and relapse, higher rates of drug persistence and better clinical outcomes in patients who undergo proactive TDM compared to reactive TDM [8–11]. The authors aimed to add to this debate by carrying out a pragmatic, randomised controlled trial assessing whether proactive TDM is superior to reactive testing in children with Crohn’s Disease.
This was a multicentre, non-blinded randomised controlled trial in Israel. Biologic-naïve children (6–18 years old) with luminal Crohn’s Disease were 1:1 assigned to receiving either proactive TDM (physicians informed of drug level at scheduled intervals, n=38) or reactive testing (physicians informed of drug level after loss of response, n=40). In order to be eligible, patients must not have responded to two doses of standard induction therapy with adalimumab. They must have completed oral steroids by week 10 of study, could not have been on other treatments (i.e. 5-ASA), and must have stopped immunomodulator therapy prior to starting adalimumab or to have continued immunomodulator therapy for at least 6 months after starting adalimumab. The primary endpoint was sustained corticosteroid-free clinical remission throughout the study period (weeks 4–72). Multiple secondary outcomes, including composite clinical and biochemical endpoints, pharmacokinetics and adverse events, were also studied.
Of 78 children who underwent randomisation, 33 (87%) and 32 (80%) children completed the study in the proactive and reactive groups, respectively. There were no significant differences between the two arms, including with respect to disease duration and behaviour, immunomodulator use and biochemical evidence of inflammation. Most children were dose intensified: 87% in the proactive and 60% in the reactive group (p<0.001), and most intensifications were indicated at an earlier time point in the proactive group compared to the reactive group (median 24 vs 64 weeks). Children in the proactive group were more likely to achieve corticosteroid-free remission throughout compared to the reactive group [31 (81%) vs 19 (48%), p=0.002]. There was no difference in treatment discontinuation or disease exacerbations between the groups; however, time to relapse and dose escalation was longer in the proactive group compared to the reactive group. In regard to secondary outcomes, more children in the proactive group achieved sustained corticosteroid-free clinical remission, C-reactive protein < 0.5 mg/dL and faecal calprotectin <150 μg/g) compared to the reactive group [16 (42%) vs 5 (12%), p=0.003]. Differences between the two groups in respect of rates of clinical remission, faecal calprotectin and combined outcomes were more pronounced, and more significant, later (week 72) vs earlier (week 48) in the study.
Proactive TDM resulted in higher rates of corticosteroid-free remission and had a positive effect on mild clinical exacerbations in children with Crohn’s Disease who did not respond to induction therapy. There remains an unclear benefit of proactive TDM for moderate/severe disease exacerbations and drug discontinuation. As this trial stopped after 72 weeks, further long-term data are needed. The authors are, however, to be commended for carrying out a neat trial, particularly in light of the fact that no prospective studies have been carried out in children, and none have exclusively studied the effect of TDM on adalimumab. Although this study brings us one step further in better understanding how to use TDM, a few clinical questions remain, including When is the best time to start carrying out TDM – during induction or maintenance?, How often should patients who are in the therapeutic window be assessed? and What are the optimal drug concentrations to target ? TDM in IBD is still in its adolescence. Clinicians and researchers are advised to watch this space, as new anti-drug assays are emerging (NCT02862132, NCT02698475) and larger studies (NCT03261102, NCT03555058) are underway.
- Lamb CA, Kennedy NA, Raine T, et al. British Society of Gastroenterology consensus guidelines on the management of inflammatory bowel disease in adults. Gut 2019;68(Suppl 3):s1–106. doi: 10.1136/gutjnl-2019-318484
- Feuerstein JD, Nguyen GC, Kupfer SS, Falck-Ytter Y, Singh S, American Gastroenterological Association Institute Clinical Guidelines Committee. American Gastroenterological Association Institute guideline on therapeutic drug monitoring in inflammatory bowel disease. Gastroenterology 2017;153:827–34. doi: 10.1053/j.gastro.2017.07.032
- Papamichael K, Cheifetz AS. Is it prime time for proactive therapeutic drug monitoring of anti-tumor necrosis factor therapy in inflammatory bowel disease? Gastroenterology 2019;157:922–4. doi: 10.1053/j.gastro.2019.08.001
- Steenholdt C, Brynskov J, Thomsen OØ, et al. Individualised therapy is more cost-effective than dose intensification in patients with Crohn’s disease who lose response to anti-TNF treatment: a randomised, controlled trial. Gut 2014;63:919–27. doi: 10.1136/gutjnl-2013-305279
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- Vande Casteele N, Ferrante M, Van Assche G, et al. Trough concentrations of infliximab guide dosing for patients with inflammatory bowel disease. Gastroenterology 2015;148:1320–9.e3. doi: 10.1053/j.gastro.2015.02.031
- D’Haens G, Vermeire S, Lambrecht G, et al. Increasing infliximab dose based on symptoms, biomarkers, and serum drug concentrations does not increase clinical, endoscopic, and corticosteroid-free remission in patients with active luminal Crohn’s disease. Gastroenterology 2018;154:1343–51.e1. doi: 10.1053/j.gastro.2018.01.00.
- Papamichael K, Chachu KA, Vajravelu RK, et al. Improved long-term outcomes of patients with inflammatory bowel disease receiving proactive compared with reactive monitoring of serum concentrations of infliximab. Clin Gastroenterol Hepatol 2017;15:1580–88.e3. doi: 10.1016/j.cgh.2017.03.031
- Vaughn BP, Martinez-Vazquez M, Patwardhan VR, Moss AC, Sandborn WJ, Cheifetz AS. Proactive therapeutic concentration monitoring of infliximab may improve outcomes for patients with inflammatory bowel disease. Inflamm Bowel Dis 2014;20:1996–2003. doi: 10.1097/MIB.0000000000000156
- Fernandes SR, Bernardo S, Simões C, et al. Proactive infliximab drug monitoring is superior to conventional management in inflammatory bowel disease. Inflamm Bowel Dis 2020;26:263–70. doi: 10.1093/ibd/izz131
- Papamichael K, Vajravelu RK, Vaughn BP, Osterman MT, Cheifetz AS. Proactive infliximab monitoring following reactive testing is associated with better clinical outcomes than reactive testing alone in patients with inflammatory bowel disease. J Crohn’s Colitis 2018;12:804–10. doi: 10.1093/ecco-jcc/jjy039
Neil Chanchlani Neil is a paediatric doctor with an interest in Inflammatory Bowel Disease. He is in the second year of his PhD, which focusses on the development of personalised strategies to reduce the impact of immunogenicity to anti-TNF therapy in IBD. Affiliations: Exeter IBD Pharmacogenetics Group, University of Exeter, UK.