Therapeutic Drug Monitoring of Adalimumab During Long-term Follow-up in Paediatric Patients With Crohn Disease

Low Anti-Tumor Necrosis Factor Levels During Maintenance Phase Are Associated With Treatment Failure in Children With Crohn's Disease

BACKGROUND

Higher drug levels and combination therapy with low-dose oral methotrexate (LD-MTX) may reduce anti-tumor necrosis factor (TNF) treatment failure in pediatric Crohn's disease. We sought to (1) evaluate whether combination therapy with LD-MTX was associated with higher anti-TNF levels, (2) evaluate associations between anti-TNF levels and subsequent treatment failure, and (3) explore the effect of combination therapy on maintenance of remission among patients with therapeutic drug levels (>5 µg/mL for infliximab and >7.5 µg/mL for adalimumab).

METHODS

We conducted a post hoc analysis of the COMBINE trial, which compared anti-TNF monotherapy to combination therapy with LD-MTX. We included participants who entered maintenance therapy and provided a serum sample approximately 4 months from randomization.

RESULTS

Among 112 infliximab and 41 adalimumab initiators, median drug levels were similar between combination therapy and monotherapy (infliximab: 8.8 vs 7.5 μg/mL [P = .49]; adalimumab: 11.1 vs 10.5 μg/mL [P = .11]). Median drug levels were lower in patients experiencing treatment failure (infliximab: 4.2 vs 9.6 μg/mL [P < .01]; adalimumab: 9.1 vs 12.3 μg/mL [P < .01]). Among patients treated with infliximab with therapeutic drug levels, we observed no difference in treatment failure between participants assigned monotherapy or combination therapy. Among patients treated with adalimumab, a trend towards reduced treatment failure in the combination therapy arm was not statistically significant (P = .14).

CONCLUSIONS

LD-MTX combination was not associated with higher drug levels, but higher drug levels were associated with reduced risk of treatment failure. Among patients with therapeutic drug levels, we observed no benefit of LD-MTX for patients treated with infliximab. A nonsignificant trend towards reduced treatment failure with the addition of LD-MTX patients treated with adalimumab warrants further investigation.

Proactive monitoring of anti-TNF agents improves follow-up of paediatric patients with Crohn disease

INTRODUCTION AND AIMS

The incidence of paediatric inflammatory bowel disease has increased in recent decades. The aim of the present study was to evaluate the role of proactive and serial monitoring of tumour necrosis factor (TNF) inhibitor levels to maintain clinical remission and mucosal healing in the follow-up of paediatric patients with Crohn disease (CD).

METHODS

Prospective study that included all patients diagnosed with CD and treated with adalimumab or infliximab between May 2015 and November 2020 who underwent serial and proactive monitoring of TNF inhibitor levels.

RESULTS

The study included 30 patients, 21 male (70%). The mean age at diagnosis was 11.3 years (SD, 2.0), the mean age at initiation of TNF inhibitors was 12.6 years (SD, 1.9) with a mean duration of follow-up of 27.1 ± 9.1 months. Clinical remission was defined as a weighted Pediatric Crohn's Disease Activity Index (wPCDAI) of less than 12.5 and mucosal healing as a Mucosal Inflammation Non-invasive Index (MINI) of less than 8. During the follow-up, patients were in clinical remission in 87.1% of the visits, presented with mild disease in 11.4% and with moderate disease in 1.5%, and mucosal healing was assumed in 83% of the visits. The rates of clinical remission and mucosal healing at 1, 2, and 3 years of follow-up were 83.3%, 95.8%, 92.8%, and 86.7%, 87.5% and 85.7%, respectively.

CONCLUSIONS

Proactive and serial monitoring of serum TNF inhibitor levels may make it possible for patients to maintain clinical remission and mucosal healing in the maintenance phase, with individualised optimization of the required dosage and minimization of secondary loss of response.

Adalimumab in Pediatric Inflammatory Bowel Disease

The introduction of biological agents with strong anti-inflammatory action, such as antitumor necrosis factor (TNF) agents, has changed inflammatory bowel disease (IBD) treatment strategy and goals, and has contributed significantly to improve the long-term prognosis of patients. Moreover, several biological agents are being used or researched in pediatric populations. However, only two biological agents, infliximab (IFX) and adalimumab (ADL), are currently approved for children and adolescents. In pediatric IBD, there are limitations and burdens associated with facilitating mucosal healing (MH) when utilizing these two biological agents. ADL is effective in both naïve patients and those with previous experience with biologics. Beyond clinical remission, this drug is also effective for MH and histological remission. The use of therapeutic drug monitoring to further enhance the effectiveness of ADL treatment can be expected to reduce treatment failure of ADL and pave the way for appropriate treatment in the treat-to-target era. This review paper focuses on ADL, examine studies conducted in children, and determine the role this agent plays against pediatric inflammatory bowel disease.