Comparison of Oral Valganciclovir and Placebo for the Prevention of Cytomegalovirus (CMV) After Lung Transplantation

Inclusion Criteria for Phase I: * Adult lung transplant recipients age 18 or older * At risk for CMV (donor or recipient serology must be positive for CMV) * Adequate hematological and renal function, * On intravenous (IV) ganciclovir within 24 hours of surgery * Agreement to use effective methods of contraception * Negative pregnancy * Tolerate oral medications within 2 weeks of transplant * Negative baseline CMV PCR * Able to understand and sign the informed consent Exclusion Criteria for Phase 1: * Repeat transplantation * Mechanical ventilation at study entry * Oral or intravenous ganciclovir treatment outside the study protocol * Invasive fungal infection * Participation in another investigational study * Acute CMV infection or disease * Anti-CMV therapy within 30 days before enrollment * Uncontrolled diarrhea or malabsorption * Allergic reaction to study drug * Required use of prohibited medications * Lactating women * Pregnancy * Renal failure Inclusion Criteria for Phase II: * Negative serial post transplant PCRs at day 75 * Negative bronchial cultures for CMV * Adequate hematological and renal function at day 75 * IV ganciclovir for up to 2 weeks post operation and open label up to day 90 * Effective contraceptives * Negative pregnancy Exclusion Criteria Phase II: * Renal failure * Serious adverse events (SAE) related to study drug * CMV disease (study endpoint) * Withdraw consent for Phase II