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.

Part A: On Day 1 subjects will be converted from their routine Prograf®-based immunosuppressive regimen to a Prograf®-based immunosuppressive regimen supplied by the Sponsor as study medication and continue treatment until Day 7. The daily dose of the study medication must be the same \[1:1 (mg:mg)\] as the Prograf® dose received during the 30-day screening period.

On Day 7 the first 24 hour PK profile will be started. Samples will be taken over a 24 hour period and will be completed on Day 8.

On Day 8 subjects will be switched to once-daily Advagraf® on a 1:1 (mg:mg) total daily dose basis and continue treatment until Day 14.

On Day 14 the second 24-hour PK profile will be started. Samples will be taken over a 24-hour period and will be completed on Day 15.

Part B: One year follow-up period to evaluate safety and efficacy of tacrolimus when administered as an Advagraf®-based immunosuppressive regimen.

Part C: Continuation of long-term follow-up (from Day 365 onwards). Patients who have completed Part B and to whom continued treatment with Advagraf® is not currently available, will be offered participation in a continuation of long-term follow-up (Part C). Part C will continue until Advagraf® becomes available to these patients or these patients' discontinuation, whichever is the earliest.

Part C applies to patients in the following countries: United Kingdom, Czech Republic, Germany, Italy, and Poland only.

Eligibility Criteria:
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