Efficacy and Safety of Paricalcitol in the Reduction of Secondary Hyperparathyroidism After Kidney Transplantation.

To demonstrate the superiority of paricalcitol treatment at early renal post-transplantation (M6) in the control of iPTH (Intact parathyroid hormone) compared to the use of vitamin D nutritional supplements (calcifediol) in patients with renal transplantation.

The purpose of this study is to demonstrate the superiority of paricalcitol treatment at early renal post-transplantation (M6) in the control of iPTH (Intact parathyroid hormone) compared to the use of vitamin D nutritional supplements (calcifediol) in patients with renal transplantation.

Eligibility Criteria:
Inclusion Criteria:

* Patient that have willingly signed and dated the ICD (Informed Consent Document) approved by the EC (Ethics Committee) before any study procedure and after they have been explained the study, they have read the ICD and have had the opportunity to make questions about it.
* Patients of both genders and older than 18 years candidates to an immediately renal transplantation from living or deceased donor.
* 24 hours previous to the transplantation, patient must have a significant grade of secondary hyperparathyroidism, defined as iPTH (Intact parathyroid hormone) levels between 110 and 600 pg/mL as per central laboratory results.
* Patients with a preformed antibody panel \<20% 24 hours before the transplantation or that are considered by the investigator of low immunological risk (PRA determination is being done on local laboratory, not central).
* Serum calcium (corrected by albumin) \< 10 mg/dL 24 hour previous to the transplantation as per central laboratory results.
* Patients that are to be treated with immunosuppression based on tacrolimus, mofetil mycofenolate or mycophenolic acid and with steroids and that are not going to be treated with mTOR (mammalian target of rapamycin) inhibitors. Tacrolimus and steroids must not be removed on the 6 month post-transplantation.
* Patients that are able to take oral capsules on the first week post-transplantation.

Exclusion Criteria:

* Third or subsequent renal transplantation.
* Positive cross-match assay or ABO (A-B-0) incompatibility
* Patients that have been or are going to be recipients of other organs other than the kidney or a double kidney transplantation.
* Patients with history of allergic reaction or sensibility to paricalcitol, calcifediol or similar study drugs (related with vitamin D).
* Patients with chronic gastrointestinal disease, that, based on investigators criteria, can cause significant gastrointestinal malabsorption.
* Patient with hypo or hyperthyroidism not controlled based on investigators criteria.
* Patient with uncontrolled hypertension based on investigators criteria.
* Patients that, 48 hours previous to transplantation, have been receiving calcimimetics.
* Patients with VIH (human immunodeficiency virus)infection of positive serology for HBV (hepatitis B virus) and/or HCV (hepatitis C virus)
* Patients on treatment with drugs contraindicated with paricalcitol and calcifediol (based on SMPC)
* Patients that are participating on other clinical trial with investigational drugs.
* Women of childbearing potential (defined as those whose last menstruation was \<2 years ago and that are not surgically sterilized) that are not willing to use correct contraception during study treatment.
* Patient with other diseases or conditions that based on investigators criteria are not suitable for the study.
* Treatment will not be started if the Calcium-Phosphorus product (CAxP)is \>55 mg2/dL2 or in case of hyperphosphatemia considered significant as per investigator criteria