Calcineurin inhibitor reduction based on maintenance immunosuppression with mycophenolate mofetil in renal transplant patients: POP study.

Since calcineurin inhibitors (CNI) have been introduced, they have become the cornerstone of immunosuppression for renal transplant patients, but their cardiovascular and neurological toxicities, and primarily their renal toxicity, have brought about an increased effort to find combinations of immunosuppressants that are either CNI-free or that use minimum doses of these drugs. The weight of immunosuppression therefore lies with drugs that have a better toxicity profile. The POP observational transverse study including 213 renal transplant patients was designed to study CNI minimization strategies. The mean time of transplant evolution to the time of reduction was 9.9 +/- 11.8 months. The acute rejection rate to the start of reduction was 9.4%. Almost all the patients were undergoing treatment with CNI + mycophenolate mofetil (MMF) + steroids in the immediate posttransplantation period. When reduction was chosen, all patients were undergoing treatment with MMF (mean dose at the start of reduction = 1490.7 +/- 478.0 mg/d). Among the cohort, 66.7% of patients were being treated with tacrolimus (mean C0 levels 13.3 +/- 6.6 ng/mL) and 33.3% with cyclosporine (mean C0 levels 192.2 +/- 94.0 ng/mL; mean C2 levels 1097.5 +/- 457.6). The main reasons for withdrawal were nephrotoxicity (55.9% of the cases), as well as prevention of adverse effects (21.6%). The mean target CNI dose reduction was 41.4% +/- 21.45% in the tacrolimus group and 28.6 +/- 10.0% in the cyclosporine group. In conclusion, CNI toxicity, primarily renal toxicity, makes reduction of these drugs based on the use of full MMF doses an alternative to manage renal transplant patients.