Proactive Therapeutic Drug Monitoring -Different Time Points

Yesterday’s post outlined expert recommendations for proactive therapeutic drug monitoring (pTDM).  Today’s post reviews a study (NV Casteele et al. Clin Gastroenterol Hepatol 2019; 17: 1814-21) which identifies optimal levels at earlier time points. The authors note that “higher infliximab (IFX) concentrations during induction therapy  are correlated with long-term relapse-free and colectomy-free survival.”

The authors analyzed data from 484 patients with active ulcerative colitis (UC) from two double-blind, placebo-controlled, parallel group studies: ACT-1 and ACT-2.

Key findings:

  • IFX levels ≥18.6 mcg/mL at week 2, ≥10.6 mcg/mL at week 6, and ≥34.9 mcg/mL at week 8 were associated with Mayo endoscopic scores (MES) of ≤1 at week 8.
  • IFX level of ≥5.1 mcg/mL at week 14 was associated with MES of ≤1 at week 30
  • IFX level of ≥6.7 mcg/mL at week 14 was associated with MES of 0 at week 30

My take: In pediatric patients receiving monotherapy with an anti-TNF agent, checking earlier levels (week 6, week 8, or week 10) may help avoid low troughs which are associated with a higher likelihood of treatment failure.  This study provides guidance on target levels at earlier time points.

Related blog posts:

Disclaimer: These blog posts are for educational purposes only. Specific dosing of medications/diets (along with potential adverse effects) should be confirmed by prescribing physician/nutritionist.  This content is not a substitute for medical advice, diagnosis or treatment provided by a qualified healthcare provider. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a condition.

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