Pediatric Infectious Diseases Fellow McGovern Medical School at the University of Texas Health Science Center at Houston Pearland, Texas, United States
Background: Cytomegalovirus (CMV) is a significant pathogen in pediatric transplant patients, with higher risk of acute infection given lower likelihood of prior exposure. CMV can also precipitate graft rejection, graft-versus-host-disease, and increase the risk of opportunistic infections. CMV seronegative patients with seropositive donors (D+/R-) are at highest risk. D+/R+ and D-/R+ serostatus carry intermediate risk. Association between CMV infection and decreased patient survival has been described. Prophylaxis has been associated with a decrease in CMV infection and disease. Guidelines recommend 3 to 6 months of valganciclovir (VGV) for high-risk and intermediate risk recipients, with preemptive therapy as alternative for the latter. Pediatric data on dosing is scarce, without consensus among providers. The manufacturer, supported by guidelines, recommends body surface area (BSA)-based VGV. Associated side effects and high cost have led to implementation of low dose VGV (LDV) regimens in some institutions including ours, though discouraged by guidelines. Reports in adult data have shown similar efficacy between LDV and standard dose. Nonetheless, no data has been published on LDV in the pediatric population. Objective: Our objective was to determine CMV incidence and associated complications in pediatric kidney transplant recipients (pKTR) on LDV prophylaxis in our institution. Design/Methods: We retrospectively reviewed all pKTR (≤18 years) in our institution for the past 10 years, identified those who received only LDV, and chart reviewed up to 5 years post-transplant. LDV was defined as a daily dose of 450 mg or less, as long as the estimated BSA-based dose was over 450 mg. Primary endpoint was CMV disease. Secondary endpoints included CMV viremia, cytopenias, and organ rejection. Results: Twenty patients were identified, with mean age 8.75 years. Seven patients were high risk (D+/R-) for CMV disease. Further demographics described on Table 1. Most patients were started on 450 mg daily, while 2 received 300 mg daily. Five patients were on LDV for 90 days or less (medium risk: 1, low risk: 4). The remainder received LDV for about 254 days. Around 38 CMV PCR tests were performed per patient, with average follow up of 1157 days. No patients developed CMV viremia. One patient had CMV seroconversion within 1 year of transplant.
Conclusion(s): Based on our limited experience, LDV in pKTR can be a safe option for CMV prophylaxis, with implications in decreased likelihood of significant neutropenia. Our main limitation was a small cohort. Larger studies are needed to confirm our findings.
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