The novel immunomodulator FTY720 has been associated with a mild reduction in heart rate (HR) in clinical trials. A total of 421 patients (FTY720, n=94; mycophenolate mofetil [MMF], n=327) underwent 2-day electrocardiogram and 24-h Holter monitoring. Patients had been maintained on cyclosporine plus MMF or FTY720 (2.5 mg and 5.0 mg) for > or =12 months. No significant differences in mean hourly heart rate (HR) over 24 hrs were noted between groups. Bradycardia (HR 35-50 bpm) and sustained bradycardia (HR <50 bpm for >1 min) were more common with MMF than FTY720 (53% vs. 37% and 34% vs. 21%, respectively). Electrocardiogram parameters did not differ significantly between FTY720 and MMF groups, or between FTY720 groups, supporting the absence of a dose-dependent effect. The absence of any clinically significant effect of FTY720 on cardiac rhythm demonstrates that the reduction in HR seen after the first dose does not persist in the maintenance phase.