An open prospective pilot study on the use of rapamycin after penetrating high-risk keratoplasty

The purpose of this study was to prove efficacy and safety of systemic immunosuppression with rapamycin following penetrating high-risk keratoplasty. Rapamycin has shown its immunosuppressive potential in the rat keratoplasty model and is a component of several immunosuppressive protocols after solid organ transplantation. In this pilot study, we compared the efficacy and safety of rapamycin and mycophenolate mofetil (MMF). Ten patients (group 1) undergoing high-risk keratoplasty were included in this study, receiving rapamycin as postoperative immunoprophylaxis. Rapamycin was administered orally once daily (blood trough level 4-10 ng/ml) for 6 months. Thereafter, it was tapered over 2 weeks. The control group (group 2) consisted of 24 patients who received 1000 mg MMF twice daily for 6 months. All of the patients received postoperative medication with fluocortolone 1 mg/kg/day (tapered over 3 weeks) and prednisolone acetate eyedrops 5 times per day (tapered over 5 months). Mean follow-up of all patients (n=34) was 739 days. No immune reaction was observed in groups 1 and 2 during the first 6 months under immunosuppression. Two immune reactions occurred in group 1, and five in group 2 within a 2-year follow-up. All of the immune reactions were reversible. The side effects observed in both groups were mostly reversible. Rapamycin and mycophenolate mofetil seem to be similarly efficacious in preventing immune reactions after high-risk keratoplasty, as long as they are administered. However, we observed a broad spectrum of side effects from rapamycin.