We read the article by Park et al. with great interest. 1 The authors retrospectively studied the efficacy of low-dose oral valganciclovir (n ϭ 49) compared with the standard dose of ganciclovir (n ϭ 60) for the prevention of cytomegalovirus (CMV) disease in adult liver transplant recipients. The authors found 2 patients in each group with CMV disease within 1 year of follow-up. Both patients in the ganciclovir group were high risk for CMV (donor positive, recipient negative), while in valganciclovir group, 1 patient was high-risk and 1 was low risk. 1 Absorption of valganciclovir has been found to be 10 times higher than oral ganciclovir, with bioavailability of nearly 60% in healthy volunteers and in patients who are human immunodeficiency virus positive with CMV. Based on these findings, we agree that the greater absorption and antiviral activity of valganciclovir offers an attractive option for prophylaxis against CMV after solid-organ transplantation. [2][3][4] However, when we analyzed 203 consecutive postliver transplant recipients treated with prophylactic valganciclovir between July 2001 and May 2003, we found an overall rate of 17% symptomatic CMV, when either the donor or the recipient was exposed to CMV. It was 25.9% in the high-risk group, (donor positive, recipient negative, based on CMV serology). Some of the patients developed CMV even while on valganciclovir prophylaxis. 5,6 Since our publication, we have screened more high-risk recipients for CMV during and after valganciclovir prophylaxis and have found a higher rate than the rate published earlier.
In concurrence with our findings, a double-blind, prospective trial was conducted by Roche laboratories (manufacturers of valganciclovir and ganciclovir) in 372 posttransplantation patients with high risk for CMV disease (heart, n ϭ 56; liver, n ϭ 177; kidney, n ϭ 120; and kidney/pancreas, n ϭ 11) comparing valganciclovir and ganciclovir prophylaxis. The overall results at 6 months suggested that the rate of CMV disease (including invasive CMV) was 12.1% with valganciclovir prophylaxis compared to 15.2% with ganciclovir. However, in liver transplant recipients, the