The effect of 2-gram versus 1-gram concentration controlled mycophenolate mofetil on renal transplant outcomes using sirolimus-based calcineurin inhibitor drug-free immunosuppression

Background. We performed a sequential study to determine the efficacy and side effects of low-dose (1 g) mycophenolate mofetil (MMF) in a CNI drug avoidance regimen including sirolimus/steroids. Methods. A total of 260 kidney-only recipients were given basiliximab (232) or thymoglobulin (28) induction, and sirolimus/steroids. In addition, 160 recipients were begun on standard MMF 1 g twice daily (2-g group), while 100 recipients were begun on low-dose MMF 500 mg twice daily (1-g group). The 1-g recipients were concentration controlled to keep mycophenolic acid (MPA) C 0 levels at 1.8-4 μg/ml. Results. There were no statistically significant differences in demographics between the groups. At 6 months there were no significant differences between the 2-g and 1-g MMF groups in patient survival (96.8% vs. 96%), graft survival (92.5% vs. 95%), biopsy-confirmed and treated acute rejection (8.8% vs. 13%), or mean creatinine mg/dL (1.41±0.52 vs. 1.47± 0.67), respectively. Mean MPA C 0 levels μg/ml were (4.7 vs. 2.3) at 1 month, (4.1 vs. 3.1) at 3 months, and (3.9 vs. 2.4) at 6 months. There were no significant differences at 1, 3, or 6 months in mean WBC, HgB, or platelets, or wound complications. There were significant reductions in the number of patients reporting nausea-vomiting-dyspepsia (20.6% vs. 8%, P=0.007), diarrhea (34.3% vs. 20%, P=0.01), and abdominal pains (10.6% vs. 4%, P=0.05), between the 2-g and 1-g MMF groups, respectively. Conclusions. The use of concentration-controlled 1-g MMF results in comparable transplant outcomes with less GI toxicity during the first 6 months posttransplant in a CNI drug-free sirolimus based immunosuppressive regimen.