Study to Compare the Pharmacokinetics of Tacrolimus in Stable Pediatric Allograft Recipients Converted From Prograf® to Advagraf®

Parts A \& B: Conversion of stable pediatric allograft recipients from Prograf® immunosuppression to Advagraf® immunosuppression to compare exposure and one year follow-up for safety and efficacy. Part C: Continuation of long-term follow-up and provision of ongoing study medication to subjects to whom Advagraf® is currently not available.

Inclusion Criteria: * Must be able to swallow intact study medication capsules * Received a single solid organ transplant at least 6 months prior to entry into the study * The subject's parent(s), or their legal representative(s), has been fully informed and has given written informed consent to participate in the study. The subject has given assent where applicable * Has been receiving a Prograf® based immunosuppressive regimen for a minimum of 3 months * Negative pregnancy test prior to enrolment (females) * Must agree to practice effective birth control during the study * Stable whole blood trough levels of tacrolimus in the range of 3.5 - 15ng/mL (+/-0.5ng/mL) and clinically stable in the opinion of the Investigator Exclusion Criteria: * Previously received a multiple organ transplant * Any rejection episode within 3 months prior to enrolment or within the last 6 months that required anti-lymphocyte antibody therapy, or 2 or more rejection episodes within the last 12 months * Currently receiving Rapamycin, Certican or MPA (Myfortic®) * Chronic dysfunction of the allograft, in the opinion of the Investigator * Major changes in their immunosuppressive regimen within the last 3 months prior to entry into the study * The subject is pregnant or breast feeding