Infliximab

This is a randomized controlled trial to compare the efficacy and safety of infliximab and immunosuppressives therapy alone or in combination for pediatric Crohn's disease.

Inflammatory Bowel Disease (IBD), encompassing Ulcerative Colitis (UC) and Crohn's Disease (CD), significantly impairs patients' quality of life. Current monitoring of disease activity primarily relies on endoscopy combined with histological examination, which is associated with high costs, invasiveness, poor patient tolerance, and risks of complications. Additionally, disease activity indices and laboratory-based IBD staging metrics demonstrate limited utility and accuracy in clinical practice. This study aims to investigate the correlation between polyamine levels and their key enzymes in the polyamine metabolism pathway with IBD activity, thereby establishing a predictive model for IBD progression through polyamine and metabolite measurements; to estimate the efficacy of biologics via polyamine detection, providing a scientific basis for therapeutic selection; and to screen gut microbiota associated with polyamine metabolic alterations, offering evidence-based guidance for probiotic selection in IBD patients.

This study will compare the efficacy and safety of TDM (therapeutic drug monitoring)-based infliximab (CT-P13, RemsimaTM) intravenous therapy compared with the standard infliximab (RemsimaTM) intravenous therapy for patients with active perianal fistulzing Crohn's disease.

Pediatric Ulcerative Colitis (UC) patients with moderate to severe disease activity at high risk of colectomy. Early use of biologic agents will likely be more effective. But there were no studies identified that compared a strategy of upfront biologic-based therapy versus gradual step-up therapy. In our study, newly diagnosed moderate to severe pediatric UC patients (6-18 years old) will be randomly divided into infliximab (IFX) treatment group (Top down group, TD) and corticosteroids (CS) treatment group (Step-up group, SU). Mucosal healing rate at week 12 will be compared between the two groups. The relapse rates and sustained durations of remission within one year will also be evaluated.

Crohn's disease (CD) is a chronic non-specific inflammatory disease of the intestine. Infliximab (IFX) is a kind of one of the anti-tumor necrosis factor agents (anti-TNF) and is the main clinical treatment drug for Crohn's disease, but approximately 30-50% of patients develop a secondary non-response to respond within one year. The main cause of secondary non-response failure is the formation of anti-IFX anti-drug antibodies (ADA). The human leukocyte antigen (HLA) gene is a complex allele that has been associated with susceptibility to a variety of diseases. Studies have shown that HLADQA1\*05 allele carriage significantly increases the immunogenicity of anti-tumor necrosis factor agents (anti-TNF) and the risk of ADA formation, resulting in a significant reduction in the efficacy of IFX. Our previous retrospective study found an increased risk of ADA, IFX failure to respond and discontinuation in patients with HLADQA1\*05 variants, and that IFX in combination with immunosuppression improved clinical outcomes in wild-type genotype patients, whereas combination therapy in patients with variant genotype did not optimize clinical outcomes significantly. Therefore, we believe that the impact of HLADQA1\*05 on the efficacy of IFX in the Chinese population is unclear, and the combination of immunosuppressants in patients with variant HLADQA1\*05 genotype remains to be validated due to insufficient sample size. We hypothesized that HLADQA1\*05 wild-type CD patients would have better clinical remission when treated with IFX than HLADQA1\*05 variant patients and that the combination of immunosuppressants would improve the outcome in wild-type patients but not in variant patients. By advancing this project, we hope to provide high quality evidence on the clinical use of IFX in Crohn's disease in the Chinese population and help physicians to be more selective in the use of IFX alone or in combination with azathioprine, or to switch treatment in a timely manner.