Published online Jun 21, 2022. doi: 10.3748/wjg.v28.i23.2582
Peer-review started: October 30, 2021
First decision: March 11, 2022
Revised: March 25, 2022
Accepted: May 7, 2022
Article in press: May 7, 2022
Published online: June 21, 2022
Processing time: 229 Days and 3.9 Hours
Infliximab trough level (ITL) severely affects therapeutic outcomes of Crohn’s disease (CD) patients under infliximab (IFX). Recently, frontier research has focused on identifying ITL based on different therapeutic targets. Although previous studies have elaborated clinical value of ITL monitoring on short-term outcomes in CD patients during therapy, studies contraposing the predictive value of ITL on long-term endoscopic outcomes in CD patients are still scarce domestically and overseas.
To explore the predictive value of ITL in combination with inflammatory biomarkers on long-term endoscopic outcomes in CD with clinical remission during IFX maintenance therapy.
CD patients with endoscopic remission under long-term IFX maintenance therapy in the First Affiliated Hospital of Zhejiang Chinese Medicine University from January 2012 to December 2020 were collected. ITL and inflammatory biomarkers were continuously monitored during the therapy. The Step I study was conducted from weeks 14 to 54 of IFX treatment. The Step II study was conducted from weeks 54 to 108 of IFX treatment. Endoscopic outcomes were defined as endoscopic activity (Crohn’s disease endoscopic index of severity score > 2 points or Rutgeerts score > i1) and endoscopic remission (Crohn’s disease endoscopic index of severity score ≤ 2 points or Rutgeerts ≤ i1). Endoscopic relapse free survival was defined as endoscopic remission at the beginning of the study stage and maintaining endoscopic remission during the study stage.
At week 14, low ITL [odds ratio (OR) = 0.666, 95% confidence interval (CI): 0.514-0.862, P < 0.01] and high fecal calprotectin (FCP) level (OR = 1.002, 95%CI: 1.001-1.004, P < 0.01) increased the risk of endoscopic activity at week 54. At week 54, low ITL (OR = 0.466, 95%CI: 0.247-0.877, P < 0.01) and high C-reactive protein (CRP) level (OR = 1.590, 95%CI: 1.007-2.510, P < 0.01) increased the risk of endoscopic activity at week 108. At week 14, ITL ≤ 5.60 μg/mL [area under the curve (AUC) = 0.83, 95%CI: 0.73-0.90, P < 0.001] and FCP > 238 μg/g (AUC = 0.82, 95%CI: 0.72-0.89, P < 0.001) moderately predicted endoscopic activity at week 54. ITL ≤ 5.60 μg/mL in combination with FCP > 238 μg/g indicated 82.0% possibility of endoscopic activity. At week 54, ITL ≤ 2.10 μg/mL (AUC = 0.85, 95%CI: 0.72-0.93, P < 0.001) and CRP > 3.00 mg/L (AUC = 0.73, 95%CI: 0.60-0.84, P = 0.012) moderately predicted moderate endoscopic activity at week 108. ITL ≤ 2.10 μg/mL in combination with CRP > 3.00 mg/L indicated 100.0% possibility of endoscopic activity. From weeks 14 to 54 of IFX treatment, patients with ITL > 5.60 μg/mL had higher rate of endoscopic relapse free survival than those with ITL ≤ 5.60 μg/mL (95.83% vs 46.67%). From weeks 54 to 108 of IFX treatment, patients with ITL > 2.10 μg/mL had higher rate of endoscopic survival free relapsed rate than those with ITL ≤ 2.10 μg/mL (92.68% vs 30.77%).
Combination of ITL, CRP, and FCP contribute to long-term endoscopic prognosis monitoring. During IFX maintenance treatment, low ITL, high CRP level, and high FCP level were independent risk factors of CD patients with clinical remission in adverse endoscopy outcomes within 1-year follow-up.
Core Tip: Previous investigations, contraposing Crohn’s disease patients under infliximab (IFX) maintenance therapy, have indicated that higher IFX trough levels (ITLs) were associated with sustained drug response and clinical remission in inflammatory bowel disease patients, while lower ITLs were linked to secondary unresponsiveness of IFX. Currently, endoscopic remission or mucosal healing has been considered the main goal of biological therapy. Our study manifested that Crohn’s disease patients with higher levels of IFX blood concentration and lower levels of inflammatory biomarkers tended to have a better long-term endoscopic prognosis. Combining ITL, fecal calprotectin and C-reactive protein monitoring was helpful for the timely adjustment of IFX treatment strategy.