What is the optimal MPA dosing to prevent relapse in paediatric nephrotic syndrome?

A study suggests maintaining mycophenolic acid (MPA) area under the concentration‒time curve (AUC0‒12h) ≥31.51 μg/h/mL to significantly lower the risk of relapse in paediatric patients with nephrotic syndrome (NS).

Eighty-nine paediatric NS patients receiving MPA were included in this retrospective cohort study. The researchers analysed the factors influencing relapse using binary logistic regression. They also determined the optimal cutoff threshold using receiver operating characteristic (ROC) curves and assessed relapse-free survival via Kaplan‒Meier and Cox regression analyses.

Lower MPA AUC0‒12h levels showed a robust association with relapse (relapse vs nonrelapse group: 31.49 vs 36.48 μg/h/mL; p<0.001), with logistic regression confirming MPA AUC0‒12h as a protective factor (odds ratio, 0.93, 95 percent confidence interval [CI], 0.88‒0.99).

In ROC analysis, 31.51 μg/h/mL was established as the optimal risk reference value, with a sensitivity of 87.5 percent and specificity of 51.02 percent. Cox regression further showed that subthreshold exposure is an independent relapse risk (hazard ratio, 0.24, 95 percent CI, 0.14‒0.43; p<0.001).

In subgroup analyses, the cutoff value of 31.51 μg/h/mL was further validated as a risk reference across corticosteroid response, relapse frequency, and rituximab use, but not in focal segmental glomerulosclerosis.

In addition, “[i]ndividualized mycophenolate mofetil dosing guided by therapeutic drug monitoring is critical for optimizing outcomes,” the researchers said.