Inclusion Criteria:

1. Patient has received first or second kidney transplant.
2. Transplantation occurred at least 14 days before screening.
3. Patient at risk of CMV disease (serostatus, D+R-, D+R+ or D-R+).
4. Patient aged 18 to 68 years inclusive.
5. Patient able to tolerate oral medication from screening to follow-up.
6. Patient being treated with Valganciclovir for prophylaxis of CMV disease according to current center practice.
7. Patient on stable calcineurin inhibitor and 900 mg Valganciclovir therapy (≥ 4 days prior to Day 1).
8. Patient with stable serum creatinine (± 0.2 mg/dL) for duration of at least 4 days prior to dosing on Day 1.

9. Patient with adequate hematological and renal function defined as:

   • Estimated creatinine clearance ≥ 60 ml/min
   • Absolute neutrophil count ≥ 2500 cells/µL
   • Platelet count ≥ 100,000 cells/µL
   • Hemoglobin ≥ 9.0g/dL
10. Patient agrees to use an effective method of contraception (or abstinence from sexual activity) throughout the study period and for 90 days after follow-up, if female of child-bearing potential, or if male with a female partner of child-bearing potential.
11. Females of childbearing potential with a negative pregnancy test at screening.

12. Patient able to participate, willing to give written, informed consent and comply with the study restrictions.

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Exclusion Criteria:

• Patients with any of the following will be excluded from the study:

  1. Patient is simultaneously participating in another clinical trial, except as approved by the Sponsor.
  2. Patient has used an investigational drug within three months of screening.
  3. Patient has exhibited in the past an allergic, or other significant adverse reaction to acyclovir, Val acyclovir, ganciclovir or Valganciclovir.
  4. Patient has severe, uncontrolled diarrhea.
  5. Evidence of graft rejection as determined by the Investigator.
  6. Patient requires the use of any prohibited concomitant medications (Section 4.4).
  7. Patient has previously participated (i.e. completed Day 1) in this clinical trial.
  8. Patient is pregnant or a lactating female who will not discontinue nursing prior to study entry.
  9. Patient has received anti-CMV prophylaxis with a treatment other than intravenous cytogam, intravenous ganciclovir or Valganciclovir between transplant and enrollment.
  10. Patient with active bacterial, viral, fungal or protozoal infection.