How once-nightly sodium oxybate is processed in the body in healthy volunteers: a plain language summary

This is a plain language summary of an article originally published in the journal Sleep Medicine. Narcolepsy is a sleep condition in which people have periods of extreme sleepiness during the day. People with narcolepsy may also have symptoms of muscle weakness (cataplexy); seeing, hearing, smelling, tasting, or feeling something that seems real but isn't actually there before falling asleep or while waking up (hallucinations); an inability to move before falling asleep or while waking up (sleep paralysis); and poor sleep at night. Sodium oxybate (SXB for short) has been used to treat narcolepsy for over 20 years. For more than 20 years, the only available form of SXB needed to be taken twice each night. Twice-nightly SXB (TN-SXB) requires people to take the first dose at bedtime. Most people fall asleep within 5 to 15 minutes after the first dose. Patients then need to wake up and take the second dose of TN-SXB 2.5 to 4 hours later, which is when most of the medicine has left the body. The United States Food and Drug Administration (also called FDA) approved a once-nightly form of SXB called LUMRYZ^™ (sodium oxybate for extended-release oral suspension; ON-SXB for short) in May 2023. ON-SXB treats excessive daytime sleepiness and muscle weakness, also known as cataplexy. People with narcolepsy who take ON-SXB only need to take 1 dose at bedtime. This summary describes a study that looked at how ON-SXB enters, travels through, and exits the body of healthy volunteers (people without narcolepsy). The study measured the amount of SXB in the blood after taking SXB in 2 different ways: as a once-nightly version and as a twice-nightly version. Looking at the amount of ON-SXB and TN-SXB in the blood at different time points helps researchers see if people who take the 2 medicines, with different dosing, have the same amount of drug in the body overnight.

Overall, the study found that healthy volunteers had the same amount of SXB in their bodies after taking ON-SXB as they did after taking TN-SXB. When they took the same amounts of ON-SXB and TN-SXB, the SXB stayed in their bodies for similar amounts of time. The highest amount and the total amount of SXB in the participants' blood were similar with ON-SXB and TN-SXB. The amount of SXB in the participants' blood 8 hours after taking the medicine was significantly lower with ON-SXB than with TN-SXB. This means that people taking ON-SXB will have less medication in their blood when they wake up the next morning and may be less groggy.

The results mean that if people with narcolepsy take the same dose amount of ON-SXB or TN-SXB, their bodies will receive the same amount of SXB in their blood. ON-SXB provides an option for people with narcolepsy to take their medicine once at bedtime without the need for a middle-of-the-night dose, which can improve quality of life.