The US Food and Drug Administration (FDA) in January approved Vanda Pharmaceuticals' Hetlioz (tasimelteon), the first drug to treat non-24 sleep-wake disorder. The condition, known as non-24, is common in totally blind people with no light perception, who lack the environmental cues to synchronize their endogenous circadian rhythm with the day-night cycle. Hetlioz is a small-molecule agonist for type 1 and 2 melatonin receptors, known to play a key role in regulating circadian rhythms. Off-the-shelf melatonin (N-acetyl-5-methoxytryptamine) formulations are sold as food supplements in the US, claiming to promote sleep and ease jet lag. They have also been used to treat non-24. But dosage of these melatonin preparations varies widely, and efficacy is unreliable. In addition, no clinical trials have tested melatonin's efficacy in non-24. Phase 3 study results with Hetlioz show that if taken once daily at the same time before bedtime, the drug improves sleep-wake parameters, such as total sleep time and timing of sleep. Non-24, which can cause disrupted sleep-wake patterns and excessive daytime sleepiness, affects 80,000–100,000 people in the US. Morningstar, a Chicago-based independent investment research company, estimates $600-million peak sales for Hetlioz. “We assume that it's going to be a slow wrap-up,” says Morningstar analyst Stefan Quenneville, “which [comes] down to two main reasons: Vanda is a small biotech without the marketing heft behind them and non-24 is a relatively new indication.” Vanda, located in Washington, DC, has launched an active outreach program to increase awareness of non-24, and commercial launch is slated for the second quarter of this year.
About this article
Cite this article
Tsuey Tse, M. Circadian rhythm drug approved. Nat Biotechnol 32, 303 (2014). https://doi.org/10.1038/nbt0414-303b