Conversion Pharmacodynamic Study in Stable Renal Transplant Patients Receiving Tacrolimus Two Times a Day to a New Formulation of Tacrolimus - LCP Tacro - 1 Time a Day.

LCP-Tacro is an extended-release formulation of tacrolimus designed for once-daily dosing. Phase 1 studies demonstrated greater bioavailability than twice-daily tacrolimus capsules and no new safety concerns. * Stable kidney transplant patients can be safely converted from Adoport® twice-daily to LCP-Tacro®. * The greater bioavailability of LCP-Tacro after once-daily dosing results in similar (AUC) exposure, at a dose approximately 30% less, than the total daily dose of Adoport®. * LCP-Tacro provides a slow drug release and this results in flatter kinetics characterized by significantly lower peak-trough fluctuations. * CN is the major cellular target of the calcineurin inhibitors (CNIs) cyclosporine A (CsA) and tacrolimus. The ability of these drugs to inhibit CN activity is dependent on their binding to the respective immunophilins, cyclophilins A and B for CsA and FKBP12 for tacrolimus. * CN inhibition is a rate limiting phenomenon. Over concentrations of tacrolimus does not correlate with an increase in the CN activity.