A291 - Evaluation of Discrepancies in Valganciclovir Dosing Based on Creatinine Clearance and Estimated Glomerular Filtration Rate for Cytomegalovirus Prevention in Kidney Transplant Patients

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Author Block: K. Diehl, T. Anderson-Haag, A. Spenningsby, Hennepin Healthcare, Minneapolis, MN
*Purpose: At Hennepin Healthcare, kidney transplant patients receive valganciclovir (VGC) for cytomegalovirus (CMV) prophylaxis, and dose adjustments were historically based on creatinine clearance using the Cockcroft-Gault (C-G) equation. Practice switched to using estimated glomerular filtration rates (eGFR) on January 1, 2025. The purpose of this study is to assess the incidence of discrepancies in VGC prophylaxis dosing recommendations based on estimated kidney function using C-G and eGFR equations. Secondary outcomes capture adverse effects and efficacy with VGC between dosing strategies.
*Methods: This retrospective study includes kidney transplant recipients (transplanted between January 1, 2024, and October 1, 2025) receiving VGC prophylaxis before and after practice change. Patients were excluded if they were <18 years, pregnant, or incarcerated. A total of 86 patients were included in the initial data pull and 9 were excluded due to receiving acyclovir prophylaxis.
*Results: Of the 77 patients receiving VGC, 44 (57.1%) demonstrated discrepancies in recommended doses between the C-G and eGFR equation estimates. Seventeen patients were dosed using the C-G equation but would have received higher doses if using the eGFR equation, while 27 were dosed using the eGFR equation but would have received lower doses if using the C-G equation. Baseline demographics were similar between groups. Most patients (67/77) underwent deceased donor kidney transplant and were high immune risk receiving thymoglobulin (59/77). Most recipients were intermediate CMV risk (62/77), while 13 patients were deemed high risk. A total of 42 patients reached the target dose of 900 mg daily with higher rates in patients dosed using eGFR (76.9% vs 31.6%, p<0.001). A similar trend was seen among patients with discrepancies with 81.5% (22/27) of patients reaching target dose for eGFR based dosing vs 23.5% (4/17) of patients receiving C-G based dosing (p<0.001). Overall, 26/77 patients discontinued therapy due to leukopenia. Among patients with dosing discrepancies, rates for discontinuing therapy due to leukopenia were higher in the C-G group (41.1%, 7/17) compared to the eGFR group (29.6%, 8/27). About 17% of all patients switched to letermovir to complete therapy with similar rates between the dosing groups. Among all patients, 8 patients in the C-G group developed CMV DNAemia after completion of required prophylaxis vs 4 in the eGFR group. with median peak CMV DNAemia being higher in the C-G group (854 vs 469.5 IU/mL). Ten patients in the C-G group and 3 in the eGFR group received VGC treatment for detectable CMV DNAemia (p= 0.036). Limitations include small sample size and short term follow up post prophylaxis therapy.
*Conclusions: Using the eGFR equation to assess kidney function and provide VGC dosing recommendations allows providers to approach target doses with no observed increase in adverse effects or treatment failure.