Evaluating the impact of therapeutic drug monitoring strategies on clinical outcomes in paediatric inflammatory bowel disease.

The increasing incidence of inflammatory bowel disease (IBD) in paediatric populations underscores the importance of effective management strategies. Anti-tumor necrosis factor (anti-TNF) agents, such as infliximab (IFX) and adalimumab (ADL), are key treatments for inducing and maintaining remission in IBD, but many patients experience a loss of response over time. Different strategies of therapeutic drug monitoring (TDM) are applied to optimise anti-TNF therapy. In this study, we investigated the effect of proactive and reactive TDM on clinical outcomes and pharmacokinetic parameters in paediatric IBD patients. We conducted a retrospective multicentre study involving 391 children with IBD from the CEDATA-GPGE registry. Patients were categorised into proactive (n = 285) and reactive (n = 106) TDM groups. Clinical outcomes, laboratory results, and pharmacokinetic parameters of IFX and ADL were compared between the groups. Proactive TDM was associated with higher clinical remission rates (50% vs. 24%, p < 0.0001) and reduced hospitalisation rates (17% vs. 39%, p < 0.0001) compared to reactive TDM. In Crohn's disease patients, proactive TDM was linked to lower disease activity and improved levels of C-reactive protein and erythrocyte sedimentation rate. Proactive TDM was also associated with higher IFX drug levels, lower anti-drug antibody concentrations and less frequent switches of the biological therapy. Differences in pharmacokinetic parameters during ADL-treatment were less pronounced and no significant benefit of proactive TDM was observed. Our data suggest that proactive TDM may offer clinical and pharmacokinetic benefits, particularly for paediatric IBD patients treated with IFX, while results for other outcomes and for ADL were less clear. Prospective studies are needed to confirm these findings and to further clarify the role of proactive TDM in this population.