The cost effectiveness of tacrolimus versus microemulsified cyclosporin: a 10-year model of renal transplantation outcomes

Abstract

Introduction and objective: In 1983, the launch of cyclosporin was a significant clinical advance for organ transplant recipients. Subsequent drug research led to further advances with the introduction of cyclosporin microemulsion (cyclosporin ME) and tacrolimus. This paper presents the results from a long-term model comparing the clinical and economic outcomes associated with cyclosporin ME and tacrolimus immunosuppression for the prevention of graft rejection following renal transplantation.

Study design: A model was developed to project the costs and outcomes over a 10-year period following transplantation. The model was based on the results of a prospective, randomised study of 179 renal transplantation recipients receiving either cyclosporin ME or tacrolimus, which was conducted by the Welsh Transplantation Research Group (median follow-up: 2.7 years).

Methods: The short-term costs and outcomes were the averages from the actual head-to-head trial data. From this, the long-term costs and outcomes were extrapolated based on the rate of change in patient and graft survival at 3, 5 and 10 years post transplant, as reported in the 1995 United Kingdom Transplant Support Service Authority Renal Transplant Audit. PERSPECTIVE AND YEAR OF COST DATA: The analysis was conducted from the perspective of a UK transplant unit. Costs were at 1999 prices (pounds sterling 1 = dollars US 1.42 = Euro 1.5) and costs and outcomes were discounted at 6% and 1.5%, respectively.

Results: The model estimated that 10 years after transplantation, the proportion of patients surviving was 56% of the cyclosporin ME cohort and 64% of the tacrolimus cohort. The cumulative cost of maintenance therapy at 10 years was pounds sterling 23204 per patient maintained on cyclosporin ME versus pounds sterling 23803 per patient on tacrolimus. The cost per survivor at 10 years was pounds sterling 37000 (tacrolimus) versus pounds sterling 41000 (cyclosporin ME) and the cost per patient with a functioning graft was pounds sterling 39000 versus pounds sterling 45000. A Monte Carlo simulation of the model (10000 simulations) gave an average cost at 10 years of pounds sterling 23279 (SD pounds sterling 3457) for cyclosporin ME and pounds sterling 22841 (SD pounds sterling 3590) for tacrolimus. A (second order) probabilistic sensitivity analysis was also performed. The average cost at 10 years from a simulated cohort of 1000 was pounds sterling 23473 (SD pounds sterling 2154) for cyclosporin ME and pounds sterling 24087 (SD pounds sterling 2025) for tacrolimus.

Conclusion: Renal transplant recipients maintained on tacrolimus have better short- and long-term outcomes than patients maintained on cyclosporin ME. The long-term use of tacrolimus is a more cost-effective solution in terms of the number of survivors, patients with a functioning graft and rejection-free patients.