FTY720: Placebo‐Controlled Study of the Effect on Cardiac Rate and Rhythm in Healthy Subjects

The purpose of this double‐blind, placebo‐controlled study was to measure the effects of FTY720, a novel immunomodulator, on heart rate and rhythm in healthy volunteers. Subjects (n = 66) were randomized to FTY720 1.25 mg or 5 mg or placebo administered once daily for 7 days. Continuous telemetry revealed an acute, dose‐dependent decrease in mean heart rate (10‐bpm decrease vs placebo) following the first dose of FTY720, with a nadir generally 4 hours postdose. Although a persistent FTY720‐related decrease in heart rate was measured from day 2 to day 7, additional doses of FTY720 after day 2 resulted in no further incremental decreases. Mean PR interval increased by approximately 8 to 10 msec in FTY720‐treated subjects on day 1. FTY720 did not increase the QRS or QT interval. These results confirm that the first dose of FTY720 has a mild to moderate negative chronotropic effect.