Safety and Efficacy Study of a New Antiviral Drug to Prevent Cytomegalovirus Reactivation in Bone Marrow Transplanted Patients

Inclusion Criteria: * Seropositive for HCMV IgG antibodies before transplantation * First allogeneic Human blood precursor cell (HBPC) transplantation performed for 1 of the following diagnoses: leukaemia, lymphoma, Hodgkin's lymphoma, non-Hodgkin's lymphoma, multiple myeloma, myelodysplastic and myeloproliferative disorder * Evidence of post transplantation engraftment * Able to swallow tablets. Exclusion Criteria: * Previous anti-HCMV therapy after this allogeneic HBPC transplantation * Mismatched or cord blood transplant recipients * Current or history of end-organ HCMV disease * Graft versus host disease (GVHD) * Impaired liver function * Reduced renal function