A recent case series (A Assa et al. JPGN 2020; 71: 516-520. Therapeutic Drug Monitoring-guided High-dose Infliximab for Infantile-onset Inflammatory Bowel Disease: A Case Series) describes four infants (2 mo-12 mo) with infantile-onset IBD who received high doses of infliximab.
Treatments regimens utilized infliximab dosing of 10-22 mg/kg/dose with initial three doses over 2-4 weeks. Other prior treatments in these patients included antibiotics (eg. vancomycin/gentamicin) and corticosteroids. Sulfasalazine was administered in two of the patients.
Other Key Points:
- The authors noted that patients gradually transitioned to every 4 week therapy whild seeking to maintain trough concentrations >10 mcg/mL.
- Infants have several risk factors for inadequate serum infliximab levels. Infliximab clearance is not linearly weight-related and infants are “most susceptible for under-dosing.”
- Infliximab distribution in infants & children differs from adults with more peripheral compartment distribution, leading to lower trough levels.
- Severity of disease impacts infliximab levels and can cause a ‘sink’ effect
The authors note that higher doses may increase adverse events, including infections
My take: This study shows that highly-selected patients may need both accelerated and higher doses of infliximab to enable response. It adds to the literature that children, in general, are at high risk of under-dosing with ‘standard’ infliximab dosing.
Related blog posts:
- Modeling Trough Levels to Predict Optimal Infliximab Levels (in kids) In their study, they also simulated 1000 patients and found that only 24% of patients receiving 5 mg/kg q8weeks achieved a therapeutic level
- Is Standard Infliximab Dose Too Low in Pediatrics?
- Can Therapeutic Drug Monitoring with Monotherapy Achieve Similar Results as Combination Therapy for IBD? | gutsandgrowth
- Briefly noted: Induction Infliximab Levels | gutsandgrowth
- Proactive Therapeutic Drug Monitoring in Pediatric Crohn’s disease -Better Outcomes | gutsandgrowth