Withdrawal of Combination Immunotherapy in Paediatric Inflammatory Bowel Disease-An International Survey of Practice

Clinical impacts of immunomodulator withdrawal from anti-tumor necrosis factor combination therapy in pediatric inflammatory bowel disease

OBJECTIVES

Combination therapy consists of both anti-tumor necrosis factor (anti-TNF) and an immunomodulator (IMM) and has been shown to improve outcomes in patients with inflammatory bowel disease (IBD). This study assesses the impacts of IMM withdrawal from combination therapy to anti-TNF monotherapy in children with IBD.

METHODS

This single-center retrospective cohort study included children with IBD initiated on combination therapy between 2014 and 2019 who discontinued the IMM. We evaluated whether IMM withdrawal impacts laboratory values and disease activity. Linear mixed effects models with random intercepts were used to compare differences between groups. Chi-square and Kruskal-Wallis tests were used for comparisons between patients who did and did not require subsequent escalation of therapy.

RESULTS

One hundred and fifty-two patients discontinued the IMM which did not significantly affect disease activity. However, 18% of patients escalated therapy after IMM withdrawal, primarily due to low anti-TNF levels. Lower anti-TNF and higher erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels before IMM withdrawal were associated with subsequent escalation of therapy. Overall, there was no statistically significant effect on anti-TNF drug levels. Patients with Crohn's disease (CD) on infliximab (IFX) and methotrexate (MTX) who discontinued the IMM had an increase in mean ESR and CRP (p < 0.05).

CONCLUSIONS

IMM withdrawal from anti-TNF combination therapy may be considered safe in the setting of higher anti-TNF levels and normal serum inflammatory markers. Clinicians should consider assessing anti-TNF levels and inflammatory markers after IMM withdrawal, especially in patients with CD receiving IFX who discontinued MTX.

Therapy outcome related to adalimumab trough levels in pediatric patients with inflammatory bowel disease

OBJECTIVES

We evaluated the relationship between serum concentration and efficacy of adalimumab (ADA), an anti-tumor necrosis factor-alpha agent, in pediatric patients with inflammatory bowel disease (PIBD).

MATERIALS AND METHODS

This retrospective cross-sectional study traced 75 patients with PIBD (Crohn's disease, n = 57) treated with ADA at two tertiary centers in Finland in 2012-2018. Drug levels and drug antibody titers were chart-reviewed, and the treatment continuation rate of ADA therapy was evaluated. We also assessed the impact of trough levels in the first 3 months on the continuation of ADA within one year of therapy.

RESULTS

ADA was introduced at a median age of 13.4 years, and the median disease duration was 2.7 years. During the first year, 22 patients (29%) discontinued ADA due to either loss of response (20%, n = 15) or anti-drug antibody formation (5.3%, n = 4). Regarding trough levels in the first 3 months, 9/16 patients (56%) with trough levels <5 mg/L and 12/20 (60%) with trough levels <7.5 mg/L at 3 months discontinued the therapy by the end of the first year. In comparison, only 8/32 patients (25%) with trough levels >7.5 mg/L at 3 months discontinued treatment during the first year (p = .005). At the last follow-up (median 1.5 years), 52% of the 75 patients were on maintenance therapy and had a median trough level of 8.8 mg/L.

CONCLUSION

Higher trough levels in the first 3 months of adalimumab treatment are associated with lower rates of discontinuation due to loss of response during the first year.

Combination Immunotherapy Use and Withdrawal in Pediatric Inflammatory Bowel Disease-A Review of the Evidence

Evidence-based guidelines have been developed outlining the concomitant use of anti-tumor necrosis factor alpha (anti-TNF) agents and immunomodulators including azathioprine (AZA) and methotrexate (MTX) in both adult and pediatric populations. However, there exists a paucity of data guiding evidence-based strategies for their withdrawal in pediatric patients in sustained remission. This narrative review focuses on the available pediatric evidence on this question in the context of what is known from the larger body of evidence available from adult studies. The objective is to provide clarity and practical guidance around who, what, when, and how to step down pediatric patients with inflammatory bowel disease (IBD) from combination immunotherapy. Outcomes following withdrawal of either of the two most commonly used anti-TNF therapies [infliximab (IFX) or adalimumab (ADA)], or immunomodulator therapies, from a combination regimen are examined. Essentially, a judicious approach must be taken to identify a significant minority of patients who would benefit from treatment rationalization. We conclude that step-down to anti-TNF (rather than immunomodulator) monotherapy after at least 6 months of sustained clinical remission is a viable option for a select group of pediatric patients. This group includes those with good indicators of mucosal healing, low or undetectable anti-TNF trough levels, lack of predictors for severe disease, and no prior escalation of anti-TNF therapy. Transmural healing and specific human leukocyte antigen (HLA) typing are some of the emerging targets and tools that may help facilitate improved outcomes in this process. We also propose a simplified evidence-based schema that may assist in this decision-making process. Further pediatric clinical studies are required to develop the evidence base for decision-making in this area.