Two recent studies show how infliximab improves outcomes in Crohn’s disease.

• P Bossuyt et al. Clin Gastroenterol Hepatol 2021; 19: 947-954. Infliximab Exposure Associates With Radiologic Evidence of Healing in Patients With Crohn’s Disease
• AAM Singer et al. Clin Gastroenterol Hepatol 2021; 19: 1071-1073. Factors Associated With Development of Perianal Fistulas in Pediatric Patients With Crohn’s Disease (see previous blog: Early Treatment with Anti-TNFs and Development of Perianal Fistulas)

The first study by Bossuyt et al was a substudy (n=36) of the TAILORIX trial. Key findings:

• At week 54 of treatment, 36.4% of patients had a radiologic response, 30.3% of patients were in remission, and 71% had endoscopic features of remission
• Radiologic remission correlated with infliximab trough level at week 14 (P = .049) when the infliximab trough level cut-off value was set at 7.8 μg/mL (area under the curve, 0.74; 75% sensitivity; 86% specificity; 90% negative predictive value; 57% positive predictive value)
• Radiologic response was also associated with continuous infliximab trough levels above 5.0 μg/mL at all time points) (P = .034)
• Among patients with both radiologic and endoscopic remission, the median infliximab trough level was 8.5
• In this study, one interesting finding was that only half of patients with endoscopic remission achieved radiologic remission, especially since the cohort had a short disease duration at the onset of treatment (median duration of 1.5 months)

In the second study by Singer et al with 208 pediatric patients with Crohn’s disease, all patients had baseline cross-sectional imaging. Key findings:

• 26% had perianal fistulas at baseline
• 14/136 (10%) developed perianal fistulas within 3 years
• Non-white race increased the risk of perianal fistula
• Non-penetrating perianal lesions (NPLs) increased the risk of perianal fistulas (20% in patients with NPLs vs. 4% in those without NPLs)
• Anti-TNF treatment was associated with a decreased risk of perianal fistulas (HR 0.11); this risk reduction was seen in patients with NPLs also (HR =0.14)

My take: Good infliximab levels correlate with better outcomes.

Related blog posts:

• Efficacy of Anti-TNF Agents for Internal Fistulas
• Video for Patients: Benefits and Risks of IBD Treatment
• Anti-TNF Therapy Associated with Reduced Surgical Resections
• RISK Study -CCFA 2017 Update
• Do Biologics Alter the Natural History of Crohn’s Disease in Children?
• Here’s the Proof That Proactive Drug Monitoring Improves Outcomes in Children with Crohn’s Disease
• Real-World Experience with Proactive Therapeutic Drug Monitoring in Inflammatory Bowel Disease
• Appropriate Proactive Therapeutic Drug Monitoring
• Briefly noted: Induction Infliximab Levels
• Is there good evidence for proactive therapeutic drug monitoring of anti-TNF therapy?
• Is Standard Infliximab Dose Too Low in Pediatrics?
• Can Therapeutic Drug Monitoring with Monotherapy Achieve Similar Results as Combination Therapy for IBD? | gutsandgrowth

And from The Onion: