BOSTON, June 11, 2012 /PRNewswire/ -- Vanda Pharmaceuticals Inc. (NASDAQ: VNDA), a biopharmaceutical company focused on the development and commercialization of products for the treatment of central nervous system disorders, announced today that data presented at SLEEP, the 26th annual meeting of the Associated Professional Sleep Societies (APSS), show that seventy percent (70%) of totally blind people with sleep complaints suffer from Non-24-Hour Disorder (Non-24). Non-24 is a circadian rhythm disorder characterized by a chronically misaligned body clock. The results underscore the need for a new therapy that can regulate the circadian clock and keep it synchronized with the 24-hour day. There are currently no FDA approved medications for the treatment of Non-24. "Blind individuals who have no light perception do not receive the normal cues from daylight and darkness that regulate our sleep and wake cycles," said Dr. Phyllis Zee, Professor of Neurology, Neurobiology & Physiology and Director, Sleep Disorders Program at Northwestern University Feinberg School of Medicine in Chicago, Illinois. "The current study revealed that these patients' circadian cycles delay by an average of about thirty minutes each day, robbing them of their ability to stay in sync with a normal 24-hour schedule. Over time, patients will cycle in and out of phase resulting in frequent bouts of nighttime sleeplessness and daytime napping, which can negatively impact their day to day functioning." In a poster presentation entitled, " Seventy Percent of Totally Blind People with Sleep Complaints Are Not Entrained to the 24-Hour Clock," data were reported on the endogenous circadian period (T) for the first 143 subjects enrolled in the ongoing SET study (Safety and Efficacy of Tasimelteon to Treat Non-24), a Phase III clinical trial in totally blind patients. Circadian period was calculated by measuring a urinary melatonin metabolite and secretion rates, collected weekly for 48 hours (at 4-8 hour intervals), for each of the four collection periods. Vanda used this objective evaluation of melatonin secretion by the pineal gland to determine circadian period. Of the 143 totally blind subjects with sleep complaints in the study, 70% were found to not be entrained to a 24-hour day and, as a result, diagnosed with Non-24. Circadian period (T) in Non-24 patients ranged from 24.08 to 25.34, with a median tau of 24.45 (24 hours and 27 minutes), meaning study subject's internal clocks delay a median of 27 minutes every day. The effect is cumulative, putting subjects to sleep later and later each day until they cycle around the clock and begin again.