To compare the efficacy and safety of infliximab (IFX) biosimilar versus originator in Chinese adults with moderate-to-severe active ulcerative colitis (UC).

This retrospective cohort study enrolled 121 adults with moderate-to-severe active UC treated with IFX biosimilar or originator at the Gastroenterology Center of the Second Affiliated Hospital of Shandong University of Traditional Chinese Medicine (covering 17 provinces in China) between December 2017 and December 2023. Efficacy and safety were evaluated during the 8-week induction phase. The primary endpoint was clinical response rate at week 8. Secondary endpoints included clinical remission rate at week 8, endoscopic mucosal healing rate, C-reactive protein, stool frequency, and adverse events.

Among 121 patients, 61 received originator and 60 received biosimilar. In the biosimilar group, the clinical response rate, clinical remission rate, and mucosal healing rate of the patients at the 8th week were 73.3%, 55.0%, and 53.3%, respectively. In the original drug group, the clinical response rate, clinical remission rate, and endoscopic mucosal healing rate of the patients at the 8th week were 70.5%, 56.7%, and 57.4% respectively. There were no statistically significant differences (all P>0.05). Both groups showed significant reductions in CRP and stool frequency from baseline (P<0.05), with comparable post-treatment values between the two groups (P>0.05). Three patients (2.5%) experienced adverse events: two in the originator group (mild pruritus on both upper limbs, alopecia) and one in the biosimilar group (mild chest tightness).

Infliximab biosimilar demonstrates comparable efficacy and safety to the originator in inducing clinical remission in Chinese adults with moderate-to-severe UC.