Objective Infliximab (IFX) has an established role in Crohn’s disease (CD), with serum trough levels of IFX (TLI) increasingly used to optimise dosing. We report the utility of routine, proactive TLI in children on combination therapy with immunosuppression (IS) from a single paediatric centre.
Methods This is a retrospective chart review of all children with CD receiving IFX therapy conducted betweenJanuary 2014–May 2017. Clinical phenotype, duration of therapy, TLI (µg/mL), drug antibodies, type of IS, biomarkers and changes in management were recorded.
Results 60 children (8–17 years; median 14.1 years) had 206 TLIs recorded. 56/60 (93%) were on IS, with 5/60 (8%) developing antidrug antibodies (ADAs). 63/206 TLIs were recorded duringan episode of relapse (median 3.0 µg/mL) vs 143/206 TLIs recorded in remission (median 5.2 µg/mL). For children with TLI <3 µg/mL, 31/63 (49%) were in relapse vs 30/143 (21%) in remission. For children with TLI >7 µg/mL, 7/63 (11%) were in relapse vs 46/143 (32%) in remission. Change in management resulted from 43/206 (21%) TLIs in 31/60 (52%) children: 21 dose escalations, 12 de-escalations and 10 changed to adalimumab. Of 31 postinduction TLIs, 15/17 (88%) children with TLI >7 µg/mL achieved clinical and biochemical remission for the duration of therapy (median 14 months), while 4/5 (80%) children with TLI <3 µg/mL required early dose escalation. Combination therapy with thiopurines (TP) (median TLI 4.9 µg/mL) versus methotrexate (MTX) (median TLI 5.2 µg/mL) achieved comparable levels with no difference in relapse frequency.
Conclusions Routine, proactive TLIs guide optimal management in children with CD. Postinduction and during maintenance, levels <3 µg/mL were associated with relapse and levels >7 µg/mL with sustained remission. Combination IS with TP and MTX appears to offer comparable TLI and ADA rates.
- paediatric practice
- inflammatory bowel disease
- therapeutic drug monitoring
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Contributors CJB was involved in obtaining ethics approval, analysed the data, wrote the original and subsequent revisions of the manuscript, and agreed to the final manuscript. CR, LS-H and FB were involved in data collection, provided critical review and approved the final manuscript. PJL conceptualised this study, was involved in data collection and analyses, provided critical review of the original and subsequent manuscript drafts, and agreed to the final manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests PJL has received honoraria from both AbbVie and Janssen-Cilag.
Patient consent Not required.
Ethics approval This study was approved by the Human Research Ethics Committee of Children’s Health Queensland, which is compliant with the Australian NHMRC guidelines and accepted international standards.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Medical data set only available to clinicians directly managing patient care.
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