Does therapeutic drug monitoring (TDM) of trough concentrations suffice for optimizing preemptive therapy with ganciclovir of cytomegalovirus infections in non-renal solid organ transplant recipients?

OBJECTIVES

The aim of this study is to explore the relationship between ganciclovir exposure and clinical efficacy and/or safety in non-renal solid organ transplant (SOT) recipients receiving preemptive therapy with ganciclovir/valganciclovir and undergoing therapeutic drug monitoring (TDM)-guided dosing optimization.

METHODS

Non-renal SOT recipients admitted to IRCCS Azienda Ospedaliero-Universitaria of Bologna receiving preemptive therapy with ganciclovir or valganciclovir for active cytomegalovirus (CMV) infection and who underwent at least one TDM were included. Desired ganciclovir C range was set at 1-3 mg/L, and average ganciclovir trough concentrations (C ) were calculated for each patient. Reduced CMV viral load below the lower limit of quantification (LLQ) at 30 days and occurrence of myelotoxicity were selected as the primary outcome. Univariate analysis was performed by comparing patients with average C below or above 1 or 3 mg/L. Receiver operating characteristic (ROC) curve analysis was performed to identify the average ganciclovir C cut-off predictive for clinical efficacy or toxicity.

RESULTS

Twenty-nine out of 89 retrieved patients met the inclusion criteria, with a median (interquartile [IQR]) baseline CMV viral load of 27,163 copies/mL (IQR 13 159.75-151 340.25 copies/mL). Reduced CMV viral load below the LLQ at 30 days was found in 17 patients (58.6%). No difference was found in the primary outcome between patients showing average C below or above 1 mg/L (100.0% vs. 53.8%; p = .25) and/or 3 mg/L (65.2% vs. 33.3%; p = .20). ROC analysis did not allow to identify an average C cut-off predictive of clinical efficacy or toxicity.

CONCLUSIONS

No clear relationship between ganciclovir C and neither CMV eradication nor safety issues was identified.