Valganciclovir to Prevent Cytomegalovirus Infection in Kidney and Kidney/Pancreas Transplant Recipients

This study will compare different ways of giving the drugs ganciclovir and valganciclovir to kidney or kidney and pancreas transplant recipients to determine the most effective dose of valganciclovir for protecting against cytomegalovirus (CMV) infection in these patients. One of the most common viral infections following organ transplant, CMV can cause serious illness and even death. Ganciclovir reduces the incidence of CMV disease after kidney transplantation. The drug is given either intravenously (through a vein) twice a day or by mouth 3 times a day. Valganciclovir is converted to ganciclovir in the body and is absorbed into the bloodstream better than oral ganciclovir. In most transplant patients, a single daily dose of valganciclovir prevents CMV. Because of these advantages, some transplant patients are being given valganciclovir instead of ganciclovir to prevent CMV infection. However, the drug has not been studied in kidney and kidney transplant patients. This study will provide dosing information for this patient population. Patients 18 years of age and older who have had a kidney or kidney and pancreas transplant at the NIH Clinical Center may be eligible for this study. Participants will undergo the following treatments and procedures: \- Phase 1 - Treatment with intravenous ganciclovir for at least 7 days after transplantation. Sometime before starting phase 2, patients will provide a 24-hour urine collection to test for kidney function. The day before starting phase 2, they will have a cannula (small needle) inserted into an arm vein for about 12 hours to draw blood samples-one before starting the ganciclovir infusion, then at 15, 30, 60, and 90 minutes, and 2, 4, 6, 8, and 12 hours after the dose. * Phase 2 - Treatment with oral valganciclovir once a day for 7 to 21 days at a dose approximately equivalent to intravenous ganciclovir. Sometime between 4 and 21 days on this dose, patients will have blood sampling in the morning before taking the dr