Temporary mycophenolate discontinuation and reintroduction in pediatric kidney transplantation: predictors and long-term outcomes

BACKGROUND: Temporary discontinuation of mycophenolate mofetil (MMF) is frequently required in pediatric kidney transplant recipients, most often in response to viral complications. However, data regarding the long-term safety of MMF discontinuation, feasibility of reintroduction, and predictors of the need for MMF withdrawal in children remain limited. METHODS: We conducted a retrospective, single-center cohort study of pediatric kidney transplant recipients with longitudinal follow-up. Clinical, virologic, immunologic, and transplant-related data were collected. Outcomes included longitudinal estimated glomerular filtration rate (eGFR), biopsy-proven acute rejection, graft loss, de novo donor-specific antibody (dnDSA) development, unplanned hospitalization, and MMF reintroduction. Factors associated with MMF discontinuation were evaluated using multivariable regression analysis. RESULTS: Among 65 pediatric kidney transplant recipients, 22 (33.8%) required temporary MMF discontinuation, most commonly within the first post-transplant year. Opportunistic viral infections accounted for the majority of MMF withdrawal events, with BK virus as the predominant indication. MMF reintroduction was feasible in most patients (15/22). Longitudinal eGFR trajectories, rates of rejection, graft loss, dnDSA development, and unplanned hospitalization did not differ between patients who discontinued MMF and those who maintained full therapy. Younger age at transplantation emerged as the sole independent predictor of the need for MMF discontinuation. CONCLUSIONS: In this real-world pediatric cohort, temporary MMF discontinuation, when clinically indicated, closely monitored, and followed by cautious reintroduction, was not associated with adverse long-term graft outcomes. Younger age at transplantation was associated with a higher likelihood of MMF discontinuation, supporting individualized immunosuppression strategies and proactive efforts to identify children at risk for viral-driven immunosuppression intolerance.