Adalimumab therapy in pediatric Crohn's Disease: a two-year follow-up comparing 'top-down' and 'step-up' strategies.

OBJECTIVE: European Crohn's Colitis Organization (ECCO) and the European Society of Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) guidelines recommend the early use of anti-TNF biologicals in pediatric Crohn disease (CD) patients with positive predictors for poor outcome.The objective of the present study was to compare early "Top-Down" use of Adalimumab (ADA) immunomodulator/biologics-naïve patients to conventional "Step-Up" management.

METHODS: One hundred and twenty consecutive patients with a confirmed diagnosis of CD and treated with Adalimumab (ADA) between 2008 and 2019 were included and allocated to the ADA-Top Down (n=59) or ADA-Step Up group (n=61). The primary endpoint was prolonged steroid-/enteral nutrition-free clinical remission at 24 months, defined by a wPCDAI < 12.5. Clinical and biological data were collected at 12 and 24 months.

RESULTS: At start of ADA, disease activity was comparable between the ADA-Top Down group and the ADA-Step Up group (wPCDAI=31 ± 16 versus 31.3 ± 15.2 respectively, p=0.84). At 24 months, the remission rate was significantly higher in the ADA-Top Down group (73% versus 51%, p<0.01). After propensity score, the Top-Down strategy is still more effective than the Step-Up strategy in maintaining remission at 24 months (HR=0.36, 95%CI[0.15-0.87], p=0.02). Patients in the ADA-Top Down group were mainly on monotherapy compared to patients in the ADA-Step Up group (53/55 versus 28/55 respectively, p<0.001). Serum levels of Adalimumab were higher in the ADA-Top Down group than in the ADA-Step Up group (12.8µg/ml±4.3 versus 10.4µg/ml±3.9 respectively, p<0.01).There were no serious adverse events.

CONCLUSION: Early use of ADA appears to be more effective in maintaining relapse-free remission at 2 years, while using it as monotherapy. These findings further favor the recommendation of early anti-TNF use in high-risk CD patients.