The experimental drug tasimelteon has passed its second late-stage trial with surprisingly good results, showing the effectiveness of the drug in treating a rare condition called non-24-hour sleep-wake disorder (non-24).

Non-24 is a serious cicardian rhythm sleep disorder characterized by hourly delays in sleep onset and wake times due to a person’s body clock not properly adjusting to the light/dark cycle. This results in people being unable to sleep at night and then feeling exhausted and tired during the day. It is a somewhat rare disorder, only affecting an estimated 1 in every 2,000 people – although quite common among blind people. As of yet, there isn’t any approved form of treatment.

The drug developed by Vanda regulates the circadian rhythm, acting as a melatonin agonist. It works by resetting a person’s master body clock in the hypothalamus, which stabilizes the melatonin and cortisol rhythms to a regular 24-hour day-night cycle.

The RESET study was carried out to evaluate the efficacy and safety of the drug in treating people with 24-hour.

In the first late-stage trial, tasimelteon was found to be significantly better than placebo. It involved a total of 20 patients who were given 20mg of tasimelteon for a duration of 2 months. The end results of the first trial were very impressive and highlighted just how effective the drug is. It revealed that maintenance of entrainment of melatonin was superior among the tasimelteon group.

The second trial showed similar results in that the patients on tasimelteon had significantly better maintenance of entrainment of the cortisol rhythm compared to patients on placebo, and as a result, experienced much better and more normal sleep.

According to Steven W. Lockley, Ph.D., Division of Sleep Medicine, Brigham and Women’s Hospital, a teaching affiliate of Harvard Medical School:

“These results clearly demonstrate that tasimelteon can entrain the circadian clock and continued treatment is necessary to maintain entrainment. The study also shows that entrainment is associated with meaningful clinical benefits and that maintaining entrainment of the master body clock is critical to treating the problems caused by Non-24.”

Vanda Pharmaceuticals Inc, which has been seeing its share value shoot up as a result of this news, announced it will send a request for approval of the drug around the middle of the year.

Mihael H. Polymeropoulos, M.D., President and CEO of Vanda, concluded:

“We are excited by these results as they move us one step closer towards providing a treatment for blind individuals with Non-24. These results also highlight the importance of chronic therapy in treating Non-24. We are confident that if approved, tasimelteon may significantly improve the quality of life for individuals with Non-24.”

Phase III trials in 2008 indicated that the drug also shows promise for those suffering from insomnia.

Written by Joseph Nordqvist