Vanda Pharmaceuticals’ compound tasimelteon has shown for the first time to reset the body clock and to align it to a constant 24-hour day in patients suffering from Non-24-Hour Sleep-Wake Disorder. Tasimelteon is a circadian regulator in development for the treatment of the sleep-wake disorder in completely blind individuals with no light perception.

This observation was made in four patients during the initial run-in segment of the RESET study.  RESET is a phase III study of the maintenance effect of tasimelteon in the treatment of Non-24-Hour Sleep-Wake Disorder, which affects over 50% of all completely blind individuals in the U.S. Vanda intends to enroll a total of 20 tasimelteon responders in this study.

Circadian regulation is necessary for the treatment of the disorder and is predictive of a beneficial effect on both nighttime sleep and daytime naps. While light resets the body clock in sighted individuals, keeping it synchronized with the 24-hour day, this effect is lost in completely blind individuals with no light perception.

Vanda is currently studying the efficacy of tasimelteon in Non-24-Hour Sleep-Wake Disorder in two phase III studies, SET and RESET, which are ongoing and expected to be completed by the end of 2012.