The purpose of this study is to determine whether cyclosporine A (in a micro emulsion formulation) monitored by sample taken 2 hour after oral dose (C-2h) will show equivalent or superior efficacy compared to tacrolimus monitored by pre-dose blood concentration (C-0h). In addition this study will assess the safety and tolerability of a cyclosporine A regimen based on C-2h monitoring in comparison to the standard tacrolimus regimen.