Valcyte™ is a product of Roche Laboratories, Nutley, New Jersey. Patients will receive 450 or 900 mg per day depending on the stage of the study and the individual’s randomization. Dosage will be adjusted for renal insufficiency as per package insert. If creatinine clearance (crcl) is >60 (ml/min), no adjustment is needed. If crcl is 40-59, patients can only receive up to 450 mg once daily. Therefore, those randomized to the 900mg/day cohort will receive 450 mg and those randomized to receive 450 mg/day will receive 450 mg every other day (QOD). If creatinine clearance is less than 40 and will never improve, patients will be excluded or terminated from the study.