Mycophenolate mofetil versus enteric-coated mycophenolate sodium: a large, single-center comparison of dose adjustments and outcomes in kidney transplant recipients.

Background: Although enteric-coated mycophenolate sodium (EC-MPS) was developed to reduce gastrointestinal (GI) side effects in kidney transplantation, a multicenter clinical trial of patients undergoing de novo renal transplantation found that efficacy failure and adverse GI event rates for EC-MPS were comparable with mycophenolate mofetil (MMF). A common strategy to mitigate mycophenolic acid-related GI adverse events includes dose manipulations such as split dosing, dose reduction, and discontinuation. Several studies have demonstrated that dose alterations with MMF are associated with poorer graft outcomes.

Methods: To determine whether there was a clinically significant difference in dose alterations and outcomes with EC-MPS compared with MMF, we conducted a retrospective study comparing MMF and EC-MPS in all consecutive kidney transplants (n=1709) between 2000 and 2006.

Results: Graft survival between MMF and EC-MPS patients was not different during the study period (P=0.9928). The incidence of biopsy-proven acute rejection at 2 years was higher in the MMF group (30.2% MMF vs. 21.9% EC-MPS, P=0.0004). The adjusted risk of dose reductions was significantly higher in MMF-treated patients (hazard ratio=1.703, P<0.0001). Similarly, the adjusted risk of drug discontinuation was higher in the MMF group (hazard ratio=1.507, P=0.0002). EC-MPS patients also demonstrated a trend toward a lower incidence of infections and a significantly lower incidence of fungal infections.

Conclusion: EC-MPS was associated with fewer dose reductions or discontinuations, which may have translated into the observed significantly lower incidence of biopsy-proven rejection. EC-MPS has become the mycophenolic acid agent of choice at this large center.