The following is a summary of “Dysbiosis and Associated Stool Features Improve Prediction of Response to Biological Therapy in Inflammatory Bowel Disease,” published in the March 2024 issue of Gastroenterology by Caenepeel, et al.

Dysbiosis of the gut microbiota is recognized as a significant contributor to inflammatory bowel disease (IBD) pathogenesis. For a study, researchers sought to investigate potential associations between microbiota composition and outcomes of biological therapies in patients with IBD.

They prospectively enrolled 296 patients with active IBD (203 with Crohn’s disease, 93 with ulcerative colitis) who were initiating biological therapy. Quantitative microbiome profiles of pretreatment and posttreatment fecal samples were obtained using flow cytometry combined with 16S amplicon sequencing. Therapeutic response was assessed through endoscopy, patient-reported outcomes, and changes in fecal calprotectin. The effect of therapy on microbiome variation was evaluated using constrained ordination methods. Prediction of therapy outcome was performed using logistic regression with 5-fold cross-validation.

At baseline, 65.9% of patients harbored the dysbiotic Bacteroides2 (Bact2) enterotype, with a significantly higher prevalence among patients with ileal involvement (76.8%). Microbiome variation was associated with the choice of biological therapy rather than with therapeutic outcomes. Anti–tumor necrosis factor-α treatment resulted in a microbiome shift away from Bact2, accompanied by increased microbial load and butyrogen abundances, and decreased potentially opportunistic Veillonella. Remission rates for patients with Bact2 at baseline were significantly higher with anti–tumor necrosis factor-α than with vedolizumab (65.1% vs 35.2%). A prediction model incorporating anthropometrics, clinical data, stool features (microbial load, moisture, and calprotectin), and Bact2 detection predicted treatment outcomes with 73.9% accuracy for specific biological therapies.

Fecal characterization based on microbial load, moisture content, calprotectin concentration, and enterotyping may assist in selecting the appropriate biological therapy for patients with IBD.

Reference: gastrojournal.org/article/S0016-5085(23)05598-1/abstract