NASPGHAN Position Paper Outlines Therapeutic Drug Monitoring Targets for Pediatric IBD

Key Takeaways

• Children with Crohn’s disease or ulcerative colitis have fewer medication options than adults with IBD. Therapeutic drug monitoring (TDM), which checks blood levels of a biologic to guide dosing, helps get the most from available therapies.
• For infliximab, a 2025 NASPGHAN position paper recommends a trough level (the lowest drug level, measured just before the next dose) above 18 ?g/mL at the week 6 induction check and above 7 ?g/mL at week 14, followed by proactive monitoring every 6-12 months during maintenance.

Getting the Most from Fewer Options

Children with IBD have fewer medication options than adults. A position paper from the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition (NASPGHAN), published in the Journal of Pediatric Gastroenterology and Nutrition, gives clinicians guidance on using drug levels to get the most from the biologics available to children.

Ashish S. Patel, MD, physician-in-chief at Phoenix Children’s, co-authored the paper.

“Since there is limited availability of medications in pediatrics versus adult patients with IBD, the role of therapeutic drug monitoring is vital to optimization and prospective management of the therapies that are available,” said Dr. Patel.

Proactive vs. Reactive Therapeutic Drug Monitoring (TDM)

Proactive monitoring tests drug levels before problems appear and anticipates changes, to help keep the disease from coming back or the child from developing resistance to the therapy. Reactive monitoring checks levels after a problem appears. Dr. Patel said by that point, it is often too late to make changes that keep the child on the therapy, and a switch to a different therapy is often needed.

Trough Level Targets by Drug and Disease Type

The paper includes a table of target drug levels for biologics, supported by data from published research, organized by disease type. For infliximab, it recommends a trough level above 18 ?g/mL at the week 6 induction check and above 7 ?g/mL at week 14, the end of induction, followed by proactive monitoring every 6-12 months during maintenance.

Targets differ for some groups. Children with perianal fistulas may need higher drug levels. Children diagnosed before age 6 often clear the drug faster and may need more intensive dosing with close monitoring.

TDM for Newer Biologics

TDM also applies to newer biologics that work differently from anti-TNF agents, and the paper includes data on a few of them. With anti-TNF therapy, monitoring tracks both drug levels and the antibodies the body can make against the drug. With newer biologics, the focus is on drug levels, with less concern about antibody formation.

When to Call a Pediatric IBD Specialist

Dr. Patel said any concern about active disease in a child on a biologic for Crohn’s disease or ulcerative colitis should trigger a conversation with a pediatric IBD specialist. That includes intestinal symptoms such as diarrhea, blood in the stool, weight loss, abdominal pain or growth failure. It also includes symptoms outside the gut, such as joint pain, skin rashes, eye or mouth involvement, or abnormal liver tests.

Clinical Implications for Your Practice

• Drug levels checked only after a problem appears may come too late to keep a child on a therapy.
• Infliximab targets change over the course of treatment. Children with perianal fistulas or a diagnosis before age 6 may need higher drug levels, more intensive dosing or closer monitoring.
• When assessing a child on a biologic, look for symptoms outside the gut as well as intestinal symptoms.

Pediatric IBD Care at Phoenix Children’s

The Division of Gastroenterology and GI Surgery at Phoenix Children’s sees every kind of IBD case, from straightforward cases that reach lasting remission after diagnosis and treatment to very complex cases. That includes children with complex disease, children diagnosed before age 6, children who need surgery and children on combination biologic therapy.

NASPGHAN is the national pediatric GI society. Dr. Patel said having Phoenix Children’s physicians among its leaders reflects the health system’s clinical excellence, focus on education and research, and quality of care.

How to Refer

To discuss a complex or refractory pediatric IBD case (one that is not responding to treatment), contact Anne Rabasca, RN, nurse specialty care coordinator, at 602-933-5754. For other referrals to the Division of Gastroenterology and GI Surgery, call 602-933-KIDS (5437) or submit a referral online.

Ashish S. Patel, MD,

About the Author

Ashish S. Patel, MD
Physician-in-Chief, Phoenix Children’s

Dr. Patel is physician-in-chief at Phoenix Children’s and a pediatric gastroenterologist whose clinical and research focus is inflammatory bowel disease. He is board certified in pediatrics with subspecialty certification in pediatric gastroenterology from the American Board of Pediatrics. He completed his pediatrics residency at Texas A&M Health Science Center/Scott & White Hospital and his pediatric gastroenterology fellowship at UT Southwestern Medical Center in Dallas. Before joining Phoenix Children’s, he directed the Southwestern Pediatric Inflammatory Bowel Disease Program at Children’s Medical Center Dallas. He is a professor at the University of Arizona College of Medicine – Phoenix, is involved in four NIH-funded clinical research projects in IBD and has more than 50 original research publications, clinical guidelines and case reports.

Sources

Felipez LM, Ali S, de Zoeten EF, et al. North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition position paper on the therapeutic drug monitoring in pediatric inflammatory bowel disease. J Pediatr Gastroenterol Nutr.  2025; 81: 1100-1117. doi:10.1002/jpn3.70158