Association of Neutropenia With Valganciclovir Prophylaxis Dosing Practices Within Pediatric Solid Organ Transplant Recipients.

BACKGROUND

Prophylactic dosing of valganciclovir for cytomegalovirus prophylaxis in the pediatric solid organ transplant (SOT) population is highly variable among institutions. The purpose of this study was to assess the impact of valganciclovir dosing strategy on neutropenia in SOT recipients at a pediatric academic medical center utilizing a novel method of GFR estimation.

METHODS

A retrospective chart review was conducted to identify differences between patients with and without neutropenia. Regression modeling was used to determine whether valganciclovir dosing strategy could predict posttransplant neutropenia.

RESULTS

Of 80 patients included in the study, 32.5% were neutropenic while prescribed valganciclovir. Most patients were receiving concomitant myelosuppressive medications (sulfamethoxazole-trimethoprim [87.5%] and mycophenolate [66.3%]). Fourteen (53.8%) and 21 (38.9%) patients' doses were determined using their cystatin C-based estimated GFR in the neutropenic and non-neutropenic groups, respectively (p = NS). Rates of CMV DNAemia were < 5% in both groups. Valganciclovir dose was not predictive of the rate, odds, or degree of neutropenia. However, a higher valganciclovir dose adjusted for kidney function was associated with a higher log odds of neutropenia.

CONCLUSIONS

At our institution, where BSA-based dosing using a novel GFR method and appropriate upper limits of GFR for age is used, the rate of neutropenia was lower than previous reports in the literature. Furthermore, valganciclovir dose in milligrams per kilogram was not associated with an increased odds or degree of neutropenia. However, dose accounting for BSA and kidney function was. It is crucial to consider kidney function and the exposure to valganciclovir (vs. dose alone) when determining the risk of neutropenia.