CT-P13, an infliximab biosimilar agent, demonstrated improved pharmacokinetics in patients with Crohn disease (CD) vs ulcerative colitis (UC), according to study findings published in the Journal of Clinical Gastroenterology.
Infliximab, a monoclonal antibody, targets tumor necrosis factor (TNF) in patients with inflammatory bowel diseases, including CD and UC.
Researchers conducted a prospective, multicenter, observational study throughout 18 tertiary hospitals in South Korea from August 2016 to September 2019. Patients with CD (n=168) and UC (n=99) who had started receiving CT-P13 treatment and were biologic-naïve were included in the study. Researchers evaluated pharmacokinetics and the resulting clinical outcomes.
Two pharmacokinetic measurements included serum trough drug concentration and antidrug antibody (ADA) response, reflecting the rate of CT-P13 clearance and overall drug efficacy.
Patients with CD demonstrated significantly higher median trough drug levels compared with patients who had UC at week 2 (18.7 µg/mL vs. 14.7 µg/mL; P <.001), week 6 (12.5 µg/mL vs. 8.6 µg/mL; P <.001), and week 14 (3.4 µg/mL vs. 2.5 µg/mL; P <.001).
Over time, ADA response was significantly lower in patients with CD compared with UC at week 2 (6.3 AU/mL vs. 6.5 AU/mL; P =.046), week 30 (7.9 AU/mL vs. 11.8AU/mL; P =.007), and week 54 (9.3 AU/mL vs. 12.3 AU/mL; P =.032).
Patients with CD exhibited higher clinical response rates compared with patients with UC at week 14 (85.1% vs. 62.6%; P <.001) and week 54 (75.6% vs. 47.5%; P <.001). Correspondingly, patients with UC demonstrated increased likelihood of CT-P13 discontinuation due to inadequate efficacy compared with patients with CD (42.4% vs. 18.5%; P <.001).
Overall, patients with CD experienced higher rates of clinical remission on CT-P13 compared with patients who had UC — both at week 14 (81% vs. 33.3%; P <.001) and week 54 (72% vs. 32.3%; P <.001).
The researchers observed that factors predicting clinical remission by week 54 following CT-P13 administration included patients having CD instead of UC (adjusted odds ratio [aOR], 1.92; P <.001), low initial concentration of C-reactive protein (aOR, .87; P =.032), and no signs of ADA response development by week 2 (aOR, .15; P =.026).
“These findings demonstrate that favorable pharmacokinetics of infliximab in CD might be associated with better clinical outcomes of infliximab treatment in patients with CD than those with UC, 1 year after initiation of the drug,” the study authors noted.
Study limitations included an observational design and allowance of dose intensification only in patients with CD per government regulations on infliximab, which may have impacted results in the CD cohort.
Kim ES, Kim SK, Park DI, et al. Comparison of the pharmacokinetics of CT-P13 between Crohn’s disease and ulcerative colitis. J Clin Gastroenterol. Published online April 26, 2022. doi:10.1097/MCG.0000000000001715