Reduced kidney transplant rejection rate and pharmacoeconomic advantage of mycophenolate mofetil

BACKGROUND: Several multinational controlled clinical trials have shown that triple therapy immunosuppressive regimens which include mycophenolate mofetil (MMF), cyclosporin A (CSA) and steroids (S) are superior compared with conventional regimens which include azathioprine (AZA), CSA and S, mainly because MMF reduces the rate of acute rejection episodes in the first 6 months after kidney transplantation. Post-marketing studies are useful to evaluate the general applicability and costs of MMF-based immunosuppressive regimens. METHODS: Based on the excellent results of the published controlled clinical trials, we have changed the standard triple therapy immunosuppressive protocol (AZA+CSA+S) to an MMF-based regimen (MMF+CSA+S) at our centre. To analyse the impact of this change in regimen, we have monitored 6-month patient and graft survival, rejection rate, serum creatinine and CSA levels, as well as the costs of the immunosuppressive and anti-rejection treatments, in 40 consecutive renal transplant recipients (MMF group) and have compared the data with 40 consecutive patients transplanted immediately prior to the change in regimen (AZA group). RESULTS: Recipient and donor characteristics were similar in the AZA and MMF groups. Patient survival (37/40; 92.5% in the AZA group vs 38/40; 95% in the MMF group), graft survival (36/40 vs 36/40; both 90%) and serum creatinine (137+/-56 vs 139+/-44 micromol/l) after 6 months were not significantly different. However, the rate of acute rejection episodes (defined as a rise in creatinine without other obvious cause and treated at least with pulse steroids) was significantly reduced with MMF from 60 to 20% (P=0.0005). The resulting cost for rejection treatment was lowered 8-fold (from sFr. 2113 to 259 averaged per patient) and the number of transplant biopsies was lowered > 3-fold in the MMF group. The cost for the immunosuppressive therapy was increased 1.5-fold with MMF (from sFr. 5906 to 9231 per patient for the first 6 months). CONCLUSIONS: The change from AZA to MMF resulted in a significant reduction in early rejection episodes, resulting in fewer diagnostic procedures and rehospitalizations. The optimal long-term regimen in terms of patient and pharmacoeconomic benefits remains to be define