Study results for XYWAV, a low-sodium* oxybate, in adults with Idiopathic Hypersomnia
*XYWAV contains 131 mg of sodium at the 9-g nightly dose.
The phase 3 clinical study
XYWAV has been studied across several symptoms of IH that may affect you, including excessive daytime sleepiness (EDS), long sleep time, cognitive impairment, and sleep inertia.
- The efficacy and safety of XYWAV were studied in 154 people aged 19 to 75 with IH*
- All people in the clinical study started treatment on XYWAV. Some participants continued taking their stimulant or wake-promoting agent along with XYWAV
It’s important to know:
This study was double-blinded. That means neither the investigators who ran the study nor the people in the trial knew who got XYWAV or who got placebo during the period that measured how well XYWAV worked.
*Not everyone completed the 10- to 14-week portion of the study.
During the 2-week period of the study that measured how well XYWAV worked:
The average Epworth Sleepiness Scale (ESS) score among people who continued XYWAV was 7 POINTS LOWER than that of people who stopped taking XYWAV, indicating significantly less daytime sleepiness
In people who stopped taking XYWAV:
Daytime sleepiness increased by an average of 7 points
In people who continued to take XYWAV:
Daytime sleepiness increased by an average of 1 point
Results shown here used average scores, which were then rounded up or down. That's why the difference between scores may not always appear to add up.
The ESS is intended to measure excessive daytime sleepiness (EDS), a symptom of IH. It is not intended to make an IH diagnosis.
See where your daytime sleepiness falls on the Epworth Sleepiness Scale (ESS) and share your results with your doctor
What changes in overall IH symptoms were observed in people during the XYWAV clinical study?
- The PGIc screener was used to measure how well XYWAV helps treat symptoms of IH
- The PGIc asked participants to rate their overall IH using a 7-point scale ranging from “very much improved” to “very much worse”
Worsening was defined as “minimally, much worse, or very much worse” IH overall. Improvement was defined as “minimally, much improved, or very much improved” IH overall.
What changes in IHSS were seen during the XYWAV clinical study?
- Severity and frequency of IH symptoms is measured by a screener called the Idiopathic Hypersomnia Severity Scale (IHSS)
- The IHSS is a unique screener—it is the only one validated to measure multiple IH symptoms
- The IHSS asks participants to answer 14 questions related to the frequency and intensity of a range of symptoms, including excessive daytime sleepiness, long sleep time, cognitive impairment, and sleep inertia
- The IHSS measures frequency and severity of IH symptoms on a scale of 0 to 50
See how your symptoms measure on the IHSS. Results can be shared with your doctor.
During the period of the study that measured how well XYWAV worked:
The average IHSS score of people who continued XYWAV was 12 POINTS LESS than that of people who stopped taking XYWAV
In people who stopped taking XYWAV:
IHSS score increased by an average of 13 points
In people who continued taking XYWAV:
IHSS score increased by an average of just 2 points
Results shown here used average scores, which were then rounded up or down. That’s why the difference between scores may not always appear to add up.
See how your symptoms measure on the IHSS. Results can be shared with your doctor.
The phase 4 clinical study
The DUET study evaluated nighttime sleep and daytime symptoms in patients with IH taking XYWAV
This information is from a phase 4 study, which takes place after a treatment has been FDA-approved.
All 46 participants in the study knew they were taking XYWAV (this is called an "open-label" study). Additionally, there was no placebo group for comparison. As a result, it cannot be determined whether changes were related to treatment or to other factors. This study is descriptive and should not be used to show how well XYWAV works.
*Period of time where participants stopped taking any oxybates to help establish a baseline.
Primary endpoint: change in Epworth Sleepiness Scale (ESS)
This information is from a phase 4 study, which takes place after a treatment has been FDA-approved.
40 participants completed the ESS assessment at baseline and end of treatment. All participants who completed this outcome knew they were taking XYWAV (this is called an "open-label" study). Additionally, there was no placebo group for comparison. As a result, it cannot be determined whether changes were related to treatment or to other factors. This study is descriptive and should not be used to show how well XYWAV works.
The ESS measures a person's general level of daytime sleepiness. This study looked at the ESS scores when people started the study (17 points on average) and the scores once they had been on XYWAV (8 points on average) and found a change of -8.4.
95% confidence interval (CI) of -9.8 to -7.0. This means there is 95% confidence that the true population mean change lies between these numbers.
There was a standard error of 0.7. Standard error measures how much a result would likely change if you repeated the study with a different set of people.
Phase 4 Select Secondary Endpoint: Change in IHSS Score
- This information is from a phase 4 study, which takes place after a treatment has been FDA-approved
- 36 participants completed the IHSS assessment at baseline and end of treatment. All participants knew they were taking XYWAV (this is called an "open-label" study). Additionally, there was no placebo group for comparison. As a result, it cannot be determined whether changes were related to treatment or to other factors
- This study is descriptive and should not be used to show how well XYWAV works.
The Idiopathic Hypersomnia Scale (IHSS) measures the severity and frequency of a person's IH symptoms.
This study looked at IHSS scores when people started the study (33.2 points on average) and the scores once they had been on XYWAV (17.7 points on average) and found a change of -15.5.
95% confidence interval (CI) of -18.6 to -12.5. This means there is 95% confidence that the true population mean change lies between these numbers.
There was a standard error of 1.5. Standard error measures how much a result would likely change if you repeated the study with a different set of people.
Phase 4 Select Exploratory Endpoint: Time Spent in Deep Sleep
- This information is from a phase 4 study, which takes place after a treatment has been FDA-approved
- 40 participants had time spent in deep sleep measured at baseline and end of treatment. All participants who completed this outcome knew they were taking XYWAV (this is called an "open-label" study). Additionally, there was no placebo group for comparison. As a result, it cannot be determined whether changes were related to treatment or to other factors
- This study is descriptive and should not be used to show how well XYWAV works
This study looked at time spent in deep sleep when people started the study (51.9 minutes on average) and once they had been on XYWAV (92.5 minutes on average) and found a change of 40.6 minutes.
95% confidence interval (CI) of 25.8 to 55.4. This means there is 95% confidence that the true population mean change lies between these numbers.
There was a standard error of 7.3. Standard error measures how much a result would likely change if you repeated the study with a different set of people.
Phase 4 Select Exploratory Endpoint: Change in Total Sleep Time
- This information is from a phase 4 study, which takes place after a treatment has been FDA-approved
- 40 participants had total sleep time measured at baseline and end of treatment. All participants knew they were taking XYWAV (this is called an "open-label" study). Additionally, there was no placebo group for comparison. As a result, it cannot be determined whether changes were related to treatment or to other factors
- This study is descriptive and should not be used to show how well XYWAV works
This study looked at total sleep time when people started the study (467.5 minutes on average) and once they had been on XYWAV (413.4 minutes on average) and found a change of -54.1 minutes.
95% confidence interval (CI) of -81.3 to -26.9. This means there is 95% confidence that the true population mean change lies between these numbers.
There was a standard error of 13.4. Standard error measures how much a result would likely change if you repeated the study with a different set of people.