Immunosuppression management in renal transplant recipients with normal-immunological risk: 10-year results from the Swiss Transplant Cohort Study
Authors: Krisl Andreas , Stampf Susanne , Hauri Dimitri , Binet Isabelle , Mueller Thomas , Sidler Daniel , Hadaya Karine , Golshayan Déla , Pascual Manuel , Koller Michael , Dickenmann Michael , The Swiss Transplant Cohort Study (STCS)  
Published: December 2020

AIMS OF THE STUDY
Primary maintenance immunosuppressive therapies for renal transplant recipients underwent significant changes in recent years. We aimed to assess time trends and the impact of immunosuppressive regimens in first renal transplant recipients without immunological risk (blood group incompatibility, pre-existing donor-specific antibodies, positive B/T cell cross-match) in a prospective national multicentre cohort.

METHODS
The Swiss Transplant Cohort Study (STCS) prospectively enrols all patients receiving solid organ transplants in Switzerland since 2008 and systematically collects high quality clinical and laboratory data using standardised definitions. The current STCS nested study enrolled all adult transplant-naïve normal-immunological risk renal transplant recipients up to the end of 2017 and investigated different immunosuppressive strategies across a variety of transplantation relevant outcomes.

RESULTS
Of 1191 recipients enrolled at six transplant centres, 115 (10%) died with a functioning allograft and 92 (8%) lost their allograft during a median follow-up time of 5.8 years. The predominant immunosuppressive therapy comprised tacrolimus, mycophenolate mofetil and prednisone (73.7%), whereas 24.3% were treated with ciclosporin instead of tacrolimus. Primary immunosuppression with an mTOR inhibitor (1.1%) or other immunosuppressive combinations (0.8%) was rare. In the years following 2011, ciclosporin-based immunosuppression decreased significantly. The incidence of graft loss was significantly higher in patients with ciclosporin-based than with tacrolimus-based immunosuppression (adjusted hazard ratio [HR] 1.66, 95% confidence interval [CI] 1.29–2.14; p <0.01), but the occurrence of acute transplant rejections did not differ significantly (adjusted HR 1.48, 95% CI 0.82–2.65; p = 0.19). The longitudinal course of the renal allograft function was significantly better (p = 0.013) in recipients of tacrolimus-based immunosuppressive therapy. Graft failure-free survival was higher (HR 1.25, 95% CI 0.97– 1.6; p = 0.08) with tacrolimus-based than with ciclosporin-based immunosuppression. Cytomegalovirus infections occurred more frequently with ciclosporin-based immunosuppression (9.7% vs 6.4% after 1 year), whereas the incidence of BK virus infections was similar in both groups. The median time to prednisone discontinuation was 1.9 years and did not differ between the two groups. Eleven cases of post-transplantation lymphoproliferative disorder were observed during the follow-up period (1 with ciclosporin-based and 10 with tacrolimus-based immunosuppression).

CONCLUSIONS
The available data show that primary maintenance immunosuppression with tacrolimus has displaced ciclosporin-based therapies. The tacrolimus-based immunosuppression therapy showed consistently better results across almost all assessed clinically relevant outcomes. (ClinicalTrials.gov Number: NCT01204944)