WASHINGTON, June 5, 2013 /PRNewswire/ -- Vanda Pharmaceuticals Inc. (Vanda) (NASDAQ: VNDA) presented additional entrainment and patient-level clinical data at SLEEP 2013, the 27th Annual Meeting of Associated Professional Sleep Societies in Baltimore, from its SET (Safety and Efficacy of Tasimelteon) and RESET (Randomized-withdrawal study of the Efficacy and Safety of Tasimelteon to treat Non-24-Hour Disorder) Phase III studies of tasimelteon, a circadian regulator for the treatment of Non-24-Hour Disorder (Non-24) in totally blind individuals. Non-24 is a serious, rare and chronic circadian rhythm disorder that affects a majority of totally blind individuals who lack light perception and cannot entrain (synchronize) their master body clock to the 24-hour day. Currently there is no approved FDA treatment for Non-24. In the SET study, tasimelteon achieved the primary endpoints of entrainment (synchronizing) of the melatonin (aMT6s) rhythm as compared to placebo and clinical response as measured by entrainment plus a score of greater than or equal to 3 on the Non-24 Clinical Response Scale (N24CRS). Tasimelteon also demonstrated significant improvement versus placebo across a number of sleep and wake parameters including measures of total sleep time, nap duration, and timing of sleep, as well as in the Clinical Global Impression of Change (CGI-C), an overall global functioning scale. In treated patients, daytime naps decreased by 46 minutes per day in the worst 25% of days in a cycle and nighttime sleep increased by 57 minutes per day during the worst 25% of nights in a cycle. The RESET study demonstrated that continued treatment with 20mg of tasimelteon was required to maintain entrainment of melatonin and cortisol circadian rhythms in individuals with Non-24. Patients treated with tasimelteon maintained their clinical benefits while patients who received placebo showed significant deterioration in measures of nighttime sleep, daytime naps and timing of sleep. Furthermore, discontinuation of tasimelteon resulted in a rapid relapse of circadian entrainment and a return to misaligned circadian rhythms, reinforcing the importance of chronic therapy.