This report describes the effects of sirolimus on plasma lipids, and uses the Framingham risk model to assess the clinical importance of these effects.
Lipid data from two large controlled studies of 1295 renal transplant patients were analyzed retrospectively. Sirolimus 2 mg/day and 5 mg/day were compared with placebo or azathioprine, and administered concomitantly with steroids and cyclosporine over 12 months.
Hypercholesterolemia and hypertriglyceridemia occurred in all treatment groups and were maximal at 2–3 months. The sirolimus groups evidenced higher lipid levels than the controls, but the elevations diminished over time. At 1 year, the patients given sirolimus 2 mg/day had a mean cholesterol level 17 mg/dL greater and a mean triglyceride level 59 mg/dL greater than the controls. Among the patients given sirolimus 5 mg/day, mean cholesterol was 30 mg/dL greater and mean triglycerides were 103 mg/dL greater than the controls. Treatment with statins and fibrates was effective in reducing cholesterol and triglyceride levels, respectively, in the sirolimus-treated patients. The Framingham risk model predicted that the 17 mg/dL elevation in cholesterol would increase the incidence of coronary heart disease (CHD) by 1.5 new cases per 1000 persons per year and CHD death by 0.7 events per 1000 persons per year.
Lipid elevations observed in the sirolimus-treated patients were manageable, improved over time, and responded to lipid-lowering therapy. Based on the Framingham risk model, the CHD risks associated with these cholesterol elevations are small compared with the baseline risks of the transplant population.