Low toxicity regimens in renal transplantation: a country subset analysis of the Symphony study

Regional transplant practices may affect clinical outcomes within multinational studies. This study evaluated whether the overall results from the Symphony study can be generalized to the participating countries. De novo adult renal transplant recipients (n = 1645) were randomized to receive standard-dose cyclosporine, or daclizumab induction plus low-dose cyclosporine, low-dose tacrolimus,or low-dose sirolimus, all in addition to mycophenolate mofetil and steroids. Data for the highest patient-recruiting countries, Spain (n = 275),Germany (n = 316) and Turkey (n = 258), were compared. Patient transplant characteristics were different among the country subsets; only deceased donors in Spain, more expanded criteria donors in Germany, and mainly living donors in Turkey. Efficacy results for the three countries were consistent with that of the overall study - renal function and biopsy-proven acute rejection (BPAR)rates were superior with low-dose tacrolimus. Turkey had higher mean calculated glomerular filtration rate across all treatment groups (60.6-72.2 ml/min)compared with that of Spain (51.1-57.5 ml/min) and Germany (51.3-62.9 ml/min). Spain and Turkey had lower BPAR rates across the four treatment groups compared with the overall study; Germany had much higher rates(21.0-54.2%). These findings confirm the general applicability of the Symphony study results and highlight the importance of inclusion of patients from different geographic origins in randomized clinical trials.