TOPLINE:

There is substantial variability in therapeutic drug monitoring (TDM) use among North American pediatric rheumatology providers largely due to inadequate training and data.

METHODOLOGY:

• Researchers sent a survey to 412 US and Canadian pediatric rheumatology providers with 65 questions about their TDM practices for adalimumab, infliximab, azathioprine, cyclosporine, hydroxychloroquine, mycophenolate mofetil (MMF), and rituximab.
• Respondents were categorized as never using or ever using TDM and as high-frequency (used in at least 75% of patients in the last year) or low-frequency (used in 25% or less patients in the past year) users.
• Among 167 respondents (41% response rate), most were physicians (96%) working in academic centers (98%) in the US (74%).

TAKEAWAY:

• Most respondents had ever used TDM for TNF inhibitors (85%), though with low frequency, and MMF (82%), but few had ever used it for rituximab (9%).
• Among those ever-using TDM, 70% used it with high frequency for cyclosporine.
• The most common reason for TDM overall was secondary treatment failure, but adherence monitoring was most common for hydroxychloroquine and MMF, and toxicity monitoring was most common for azathioprine.
• Lack of training and lack of data were the most commonly cited barriers to TDM, with ever-users also citing turnaround time and lab timing issues.

IN PRACTICE: 

“It’s not surprising that there is huge variability in therapeutic drug monitoring, as there is relatively little published on how practitioners should use therapeutic drug monitoring,” said Jay Mehta, MD, MS, attending rheumatologist and associate program director of the Pediatrics Residency Program at Children’s Hospital of Philadelphia, Philadelphia, who was not involved in the research.

The study authors noted that treatment failure and toxicity related to suboptimal drug exposure “may be improved through therapeutic drug monitoring” and that additional studies should explore how to incorporate this practice into clinical guidelines.

SOURCE:

The study, presented in a poster at the Pediatric Rheumatology Symposium (PRSYM) 2026 in Minneapolis, Minnesota, was led by A. Carmela Sagcal-Gironella, MD, of Hackensack University Medical Center, Hackensack, New Jersey.

LIMITATIONS:

No specific limitations of the survey were mentioned. 

DISCLOSURES:

No external funding or disclosures were noted.