The Food and Drug Administration (FDA) has approved Hetlioz® (tasimelteon; Vanda), a melatonin receptor agonist, for the treatment of adults and pediatric patients with nighttime sleep disturbances associated with Smith-Magenis Syndrome (SMS).

The approval was based on data from a 9-week, double-blind, placebo-controlled, crossover study which assessed the effects of Hetlioz in patients with SMS. The study included two 4-week periods, separated by a 1-week washout interval. Patients aged 16 years and older received Hetlioz 20mg capsules, and patients aged 3 to 15 years received a weight-based dose of oral suspension. The primary end points were nighttime total sleep time and nighttime sleep quality from a parent/guardian-recorded diary; efficacy comparisons were based on the 50% of nights with the worst sleep quality and the 50% of nights with the least nighttime sleep in each 4-week period.

Results showed that treatment with Hetlioz was associated with a statistically significant improvement in the 50% worst nights’ sleep quality compared with placebo. While Hetlioz demonstrated improvements in the 50% worst total nighttime sleep time, the difference was not found to be statistically significant. The safety profile of Hetlioz was similar to that seen in previous studies for non-24-hour sleep-wake disorder.

Hetlioz 20mg capsules are indicated for the treatment of nighttime sleep disturbances in patients 16 years of age and older with SMS. Hetlioz LQ oral suspension, supplied as 4mg/mL in 48mL and 158mL bottles, is indicated for the treatment of nighttime sleep disturbances in pediatric patients 3 to 15 years of age with SMS. The products are not substitutable.

The oral suspension formulation is expected to be available in the first quarter of 2021.

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1.    FDA approves Hetlioz® (tasimelteon) for the treatment of nighttime sleep disturbances in Smith-Magenis Syndrome. [press release]. Washington, DC: Vanda Pharmaceuticals, Inc; December 1, 2020. 

2.    Hetlioz® (tasimelteon). Washington, DC: Vanda Pharmaceuticals, Inc: 2020.