Inclusion Criteria:  Subjects must be 18 years or older (and weigh more than 34Kg) and may be of both sexes and of any race. Subjects will be seropositive for CMV virus and will receive a seropositive graft (CMV IgG D + / R +). Subjects must be willing and able to give their written informed consent to the trial. If a subject cannot independently grant their informed consent in writing, her legal representative may do so in her place.  Women of childbearing potential (WOCBP) must perform a pregnancy test at the time of enrollment and agree to the use of a medically acceptable contraceptive method during the selection period and while receiving the medication specified in the protocol. A woman of childbearing age is considered to be any woman physiologically capable of becoming pregnant, from menarche to becoming postmenopausal, unless she is permanently sterile. Permanent sterilization methods include hysterectomy, bilateral salpingectomy, and bilateral oophorectomy. A postmenopausal state is defined as no menstruation for 12 months without an alternative medical cause. A high level of follicle stimulating hormone (FSH) in the postmenopausal range can be used to confirm a postmenopausal state in women not using hormonal contraceptives or hormone replacement therapy. However, in the absence of 12 months of amenorrhea, a single FSH measurement is insufficient.  Only women of childbearing age who adhere to the contraceptive methods recommended by the Clinical Trial Facilitation Group (CTFG) as highly effective contraceptive methods may participate, that is, with a failure rate of less than 1% per year when used consistently and correct:  Combined hormonal contraception (containing estrogen and progestin) associated with inhibition of ovulation (oral, intravaginal or transdermal). Progestin-only hormonal contraception associated with inhibition of ovulation (oral, injectable, or implantable) Intrauterine device (IUD) Intrauterine Hormone Release System (IUS) Bilateral tubal occlusion Vasectomized partner (provided the partner is the participant's only sexual partner in the WOCBP trial and the vasectomized partner has received a medical evaluation of surgical success) Sexual abstinence (defined as abstaining from sexual intercourse for the entire risk period associated with study treatments) Patients without a medical contraindication for the use of i-mTOR. Immunosuppressive induction rATG.  Exclusion Criteria:  Subjects may not have a history of type I hypersensitivity or idiosyncratic reactions to drugs ganciclovir (GCV) or valganciclovir (VGCV). Pregnant women. Breastfeeding women. Subjects may not have any clinically significant disease that could interfere with study evaluations. Participation in another clinical trial promoted by the pharmaceutical industry, in which the promoter already establishes in the protocol what the treatment of CMV should be. Patients with active viral replication of the HCV, HBV and / or HIV viruses. Patients requiring a desensitizing treatment that includes plasma exchange, Campath-1, Rituximab®, Eculizumab® and / or Gammaglobulin. Presence of donor-specific antibodies (DSA). Prior intolerance to study medication (Certican®), prior documented history of hereditary galactose intolerance, Lapp's lactase deficiency, or glucose or galactose malabsorption.