Antiproliferative Medication Dosing in Adolescent Kidney Transplant Recipients

Document Type

Conference Proceeding - Restricted Access

Publication Date

5-8-2026

Abstract

Appropriate BSA- and weight‑based dosing of mycophenolate mofetil (MMF) and azathioprine (AZA) is essential to prevent rejection in pediatric kidney transplant recipients. Adolescents experience major metabolic and body composition changes, and subtherapeutic dosing may heighten an already increased risk of rejection during this period. This multicenter retrospective study evaluates dosing adequacy of MMF and AZA at ages 10 (pre‑puberty), 13 (mid‑puberty), and 16 (post‑puberty). The primary outcome is whether subtherapeutic dosing occurs more often at ages 13 and 16 than at age 10. The secondary outcome assesses whether underdosing within these age groups correlates with rejection events in the following year.

Data will be obtained from the IROC database. Patients will be included if they are 10, 13, or 16 years old, have received a living or deceased donor kidney transplant, and are prescribed MMF or AZA. Exclusions include < 6 months post‑transplant, lack of tacrolimus, use of mycophenolate sodium, loss to follow‑up, active EBV/CMV/BK infection, BSA >2.5 m², weight >100 kg, or TPMT/NUDT15 deficiency. Standard pediatric maintenance dosing is MMF 450 mg/m² every 12 hours (max 1000 mg) and AZA 1.5-3 mg/kg daily (max 150 mg). Subtherapeutic dosing is defined as < 400 mg/m² for MMF or < 1.5 mg/kg for AZA. Continuous variables will use means or medians; categorical variables will use counts and percentages. Chi‑square, Fisher's exact, ANOVA, or Kruskal‑Wallis tests will compare groups. The study will include 100 patients per medication group to ensure adequate power.

The final take home message and potential impact of the study is if our hypothesis is confirmed, the identification of a novel mechanism underlying the suboptimal kidney transplant outcomes in teenagers. Such findings would then help transplant programs ensure that this vulnerable population is being appropriately dosed with their anti-rejection medications.

Comments

2026 Research Day Corewell Health West, Grand Rapids, MI, May 8, 2026. Abstract 1926

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