ABSTRACT
BACKGROUND: The new microemulsion formulation of cyclosporine (Neoral) has been developed in an effort to improve the reliability of drug absorption. The objectives of this study were to assess the efficacy, safety, and tolerability of Neoral compared to the original formulation (Sandimmun) in liver transplant recipients. METHODS: In a double-blind, parallel group study conducted in 28 centers across Europe and the United States, patients receiving primary orthotopic liver allografts were randomized within 24 hr of transplantation, 198 to Neoral and 192 to Sandimmun. Patients with and without T-tube biliary drainage were included. Postoperatively, all patients also received intravenous (i.v.) cyclosporine, together with prednisolone and azathioprine. Antibody induction was excluded. Efficacy measures were rejections, graft failure, patient survival, and the efficacy of the study medication in achieving the desired cyclosporine blood levels. Safety was assessed by reported adverse events, blood pressure, serum creatinine, and other routine laboratory measurements. RESULTS: Kaplan-Meier analyses showed that the Neoral group performed better than the Sandimmun group, with the estimates for patients free of treated rejection and histologically confirmed rejection either showing or approaching statistical significance at the 5% level. By 52 weeks, 5.8% (95% confidence limits: -4.4-15.9%) fewer patients required treatment of acute rejection in the Neoral group. The proportion of patients experiencing at least one treated rejection episode by 2 weeks was 29.8% for Neoral and 43.2% for Sandimmun. For histologically confirmed rejection, these proportions were 32.8% and 44.3%, respectively. The proportion of patients experiencing at least one steroid-resistant rejection was 2.0% for Neoral and 6.3% for Sandimmun at week 2, and 3.0% and 9.9%, respectively, at week 3. All these differences were significant at P<0.05. By 52 weeks, graft failure was 6.3% on Neoral and 11.4% on Sandimmun, with respective patient survival figures of 85.4% and 85.8%. The median duration of the initial episode of i.v. cyclosporine was 4.0 days for Neoral, compared to 6.5 days for Sandimmun (P<0.001). Within the first 2 weeks, a larger percentage of patients in the Neoral group reached the lower target level of cyclosporine (P< or =0.01). The weight-adjusted daily doses of study medication were lower in the Neoral group (median dose: 4.86 vs. 5.42 mg/kg/day, P=0.001), but the blood levels of cyclosporine showed no difference. For those with a T-tube, more of the patients on Neoral remained free of treated rejection throughout the study period (P=0.042, Wilcoxon). By week 2, 44.9% of these patients in the Sandimmun group required treatment for rejection compared to 30.2% in the Neoral group (P=0.007). There was no significant difference between the groups for serum creatinine, blood pressure, other biochemical and hematological variables, or reported adverse events. CONCLUSIONS: In liver transplantation in the normal clinical setting, the pharmacokinetic advantages of Neoral translate into clinical superiority over Sandimmun without a negative impact on safety. Recent data indicate that it is not optimal to use i.v. cyclosporine initially in this type of study, but the benefit was seen despite this. In keeping with the previous pharmacokinetic studies, patients managed by T-tube biliary drainage, and hence with no or limited bile available in the gastrointestinal tract, did particularly well with Neoral.
