Impact of mycophenolate mofetil on recurrent rejection in kidney transplant patients

Purpose: Mycophenolate mofetil (MMF) has emerged as a valuable adjunctive agent in renal transplantation, However, due to intolerable adverse effects associated with MMF use in our transplant population, we have used MMF selectively in patients at high risk for recurrent graft rejection, since these patients are known to be at risk for poor long-term graft outcomes. The purpose of this study was to assess the efficacy of MMF in preventing the recurrence of acute rejection following an initial rejection episode in kidney transplant patients in the first year following transplantation. Methods: Forty-four kidney transplant recipients were given MMF prospectively following treatment of their initial rejection episode to prevent recurrent rejection. MMF 1-2 g/d was given. Doses were adjusted based on tolerance; MMF therapy was to be continued for at least 6 months. The control group consisted of 124 consecutive kidney transplant recipients who had received standard anti-rejection therapy without the addition of MMF. Maintenance immunosuppression consisted predominantly of cyclosporine, prednisone + azathioprine. Antirejection therapy for both groups consisted of either corticosteroids (methylprednisolone 500 mg Lv. for 3 d or oral prednisone 2 mg/kg/d with rapid taper over 3 wk), OKT3 5 mg/d for 10 d or ATG 15 mg/kg/d for 10 d. All rejection episodes were confirmed by biopsy. Results: The majority of rejection episodes were characterized histologically as mild or moderate. Most patients (76%) received corticosteroids for treatment of their first rejection episode. There was a 68% reduction in the incidence of recurrent rejection episodes within the first year of transplant in patients receiving MMF; only 14% of recipients receiving MMF developed recurrent rejection compared to 44% of patients in the control group (p < 0.05). Approximately 50% of patients developed MMF-associated adverse effects (leukopenia, GI toxicity). Only 52% of patients remained on MMF at 6 months. One-yr graft survival was 86% in the MMF group and 89% in the control group (p > 0.05). One-year patient survival was 93 and 100%, respectively (p > 0.05). Conclusions: The addition of MMF to maintenance therapy for patients experiencing acute renal allograft rejection may prevent recurrent rejection episodes in the subsequent follow-up year.