Maintenance cyclosporin monotherapy after renal transplantation--clinical predictors of long-term outcome.

Background: There is considerable debate about whether maintenance cyclosporin (CsA) monotherapy is advisable or not in renal transplantation.
Methods: Between August 1984 and December 1989, 463 adult patients received a first cadaver graft. Initial immunosuppression was sequential: antilymphocyte or antithymocyte globulins (10-14 days), prednisone and azathioprine were combined and CsA was introduced (6-8 mg/kg/day) when the antilymphocyte or antithymocyte globulins were discontinued. When the graft function was stable and the peak of preformed lymphocytotoxic antibodies was < or = 25% and/or the number of rejection episodes was < or = 1, the steroid therapy was stopped within 1.5-3 months after transplantation, and azathioprine within 3-12 months. Patients with both anti HLA antibodies > 25% and more than one rejection episode were excluded. Cyclosporin doses were adapted for whole-blood trough levels between 100 and 200 ng/ml (monoclonal antibody radioimmunoassay or high-performance liquid chromatography). Cyclosporin monotherapy was attempted in 234 of the 463 patients.
Results: At the end of the investigation in January 1993 (follow-up time > 36 months, mean 60.5 +/- 4.5 months), 135 patients were receiving CsA without steroids or azathioprine. The 99 CsA monotherapy failures were due to rejection episodes in 48 cases, CsA A nephrotoxicity in 26 cases, and other causes in 25 cases, including five deaths and four with poor compliance. Renal function was stable in patients with successful CsA monotherapy: mean creatininaemia was 124 +/- 10 mumol/l at the time of CsA monotherapy inclusion and 129 +/- 10 mumol/l at the end of follow-up (mean time of CsA monotherapy 52 +/- 6 months). The parameters for predicting monotherapy success were age (43.2 versus 37.8. P = 0.0014), timing of trial inclusion > or = 6 months post-transplant (7.9 +/- 3 versus 5.3 +/- 3.1 months, P = 0.04), and excellent and stable renal function at the time of inclusion (124 +/- 10 versus 145 +/- 32 mumol/l, P < 0.001).
Conclusions: Maintenance CsA monotherapy was effective in 58% of low-immunological-risk first-graft patients and probably did not jeopardize overall results of our first grafts: patient and graft survival were respectively 90 and 73% at 6 years. We propose this policy to avoid long-term complications of glucocorticoid and azathioprine in selected compliant recipients with low immunological risk, follow-up time post-transplantation > 6 months, and stable creatininaemia levels.