The U.S. Food and Drug Administration approved tasimelteon (Hetlioz) for sleep disturbances in the blind.
The drug, a melatonin receptor agonist, is indicated only for totally blind individuals who have chronic non-24-hour sleep-wake disorder.
With non-24, as it is called, the circadian rhythm is disrupted, causing difficulty with the timing of sleep. People who have the condition sleep when they should not and can’t sleep when they should.
"Non-24-hour sleep-wake disorder can prevent blind individuals from following the normal daily schedule that we all take for granted," said Dr. Eric Bastings, deputy director of the division of neurology products in the FDA’s Center for Drug Evaluation and Research, Silver Spring, Md. "Hetlioz can improve the ability to sleep at night and to be active during the day."
Dr. Steven Lockley
The FDA and tasimelteon’s maker, Vanda Pharmaceuticals, estimate that 80,000-100,000 blind individuals have non-24 disorder. Tasimelteon was given priority review by the FDA because it was deemed to have the potential to significantly improve patients’ lives. Non-24 also is considered a rare condition, so tasimelteon received orphan-drug designation by the FDA, which gives it additional years of market exclusivity.
"Totally blind people have struggled with the problems brought on by non-24-hour sleep-wake disorder, sometimes for their entire life, without understanding what causes it and without being able to do anything about it," said Steven W. Lockley, Ph.D., of the sleep medicine division at Brigham and Women’s Hospital, Boston, and an investigator for Vanda. The approval "means that, for the first time, these patients have access to an approved, safe and effective treatment for their difficult debilitating disorder," Dr. Lockley said in a statement issued by Vanda.
The company evaluated tasimelteon’s effectiveness in 104 participants in two clinical trials of totally blind individuals with non-24 disorder. Patients receiving the therapy had significantly increased nighttime sleep and decreased daytime sleep duration, compared with placebo, according to the FDA.
The most common side effects were headache, elevated liver enzymes (alanine aminotransferase), nightmares or unusual dreams, disturbed night’s sleep, upper respiratory or urinary tract infection, and drowsiness. To reduce the risk of decreased mental alertness, tasimelteon should be taken at the same time every night before bedtime and activities should be limited after taking the drug, the agency said.
Vanda said that tasimelteon should be available within a few months as a 20-mg capsule. The company also has studied the drug for chronic insomnia and depression. It ended the depression studies in early 2013 and is not currently actively pursuing the insomnia indication.
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