To investigate the clinical efficacy of vedolizumab injection combined with mesalazine enteric-coated tablets in the treatment of patients with ulcerative colitis(UC).

Patients with ulcerative colitis (UC) were randomly divided into control group and treatment group using a random number table. The control group received mesalazine enteric-coated tablets: 1 g four times daily during the induction phase (weeks 0-14), and 1 g two to three times daily during the maintenance phase (from week 14 until the end of the study). The treatment group received vedolizumab injection in addition to the same mesalazine regimen as the control group. Vedolizumab was administered via intravenous infusion at a dose of 300 mg at weeks 0, 2, 6, and 14 of treatment. Clinical efficacy, levels of inflammatory factors [C-reactive protein(CRP)], fecal calprotectin], immune microenvironment indicators[T helper 17 (Th17) cells, regulatory T (Treg) cells], intestinal barrier function markers (D-lactate, endotoxin), and serum albumin were compared between the two groups at 6 months of treatment. Safety evaluations were also performed.

A total of 108 patients were screened, with 54 enrolled in each group. In the control group, 5 dropped out, leaving 49 for statistical analysis; in the treatment group, 3 dropped out, leaving 51 for statistical analysis. After 6 months of treatment, the total effective rates in the treatment and control groups were 94.12% (48/51) and 77.55% (38/49) respectively, with the treatment group significantly higher (P<0.05). The CRP levels in the treatment and control groups were (6.75±1.86) and (11.71±2.12) mg·L^-1, respectively; fecal calprotectin levels were (36.93±4.54) and (60.15±7.04) μg·g^-1, respectively; albumin levels in the experimental and control groups were (44.29±5.31) and (37.41±4.62) g·L^-1, respectively; the proportions of Th17 were (2.07±0.26)% and (2.54±0.36)%, respectively; the proportions of Treg were (4.20±0.61)% and (3.58±0.49)%, respectively; the levels of D-lactate were (4.62±0.98) and (6.99±1.42)μg·L^-1, respectively; the levels of endotoxin were (2.97±0.39) and(4.03±0.94)U·mL^-1, respectively. The differences of above indexes were all statistically significant (all P<0.05). Adverse drug reactions (ADRs) in the treatment group included nausea (2 cases), diarrhea (1 case), liver dysfunction (elevated alanine aminotransferase, 2 cases), and rash (2 cases), totaling 7 cases. ADRs in the control group included nausea (1 case), abdominal pain (1 case), kidney dysfunction (mildly elevated serum creatinine, 1 case), and rash (2 cases), totaling 5 cases. The total incidence of ADRs was 13.73% (7cases/51cases) in the treatment group and 10.20% (5cases/49cases) in the control group, with no statistically significant difference (P>0.05).

The combination of vedolizumab injection and mesalazine enteric-coated tablet improves clinical outcomes for ulcerative colitis patients without raising the incidence of adverse drug reactions.