The narcolepsy drug, developed by Irish company Jazz Pharmaceuticals, has a lower salt content than the current treatment Xyrem, making it more suitable for patients at risk of cardiovascular disease.
In a 200-patient phase III trial that finished in July, Jazz Pharmaceutical’s experimental drug was able to reduce the number of cataplexy attacks and the sleepiness of narcolepsy patients as compared to a placebo.
Narcolepsy causes disrupted sleep cycles and excessive sleepiness during the day. Around 70% of patients also suffer from attacks of cataplexy, where they suddenly lose muscle tone in parts of the body. Jazz Pharmaceuticals’ small molecule drug Xyrem is approved to treat cataplexy and sleepiness in the condition. However, it is high in salt, which is a risk factor for cardiovascular disease. Jazz Pharmaceutical’s experimental drug is similar to Xyrem but contains only 8% of the salt.
“This is important for people living with narcolepsy because narcolepsy is a chronic condition that may require lifelong treatment, and is associated with increased risk of comorbid conditions, including hypertension and cardiovascular disease,” said Richard Bogan, Associate Clinical Professor at the University of South Carolina, and lead investigator of the trial.
Jazz Pharmaceuticals first announced the success of the trial in March, before the end of the trial, and presented the full results this week at the World Sleep 2019 conference in Canada.
Jazz Pharmaceuticals got hold of Xyrem when it acquired the US company Orphan Medical in 2005. The narcolepsy drug contains gamma-hydroxybutyric acid (GHB), which is an intoxicating chemical sometimes used illegally as a club drug. While it’s not clear how Xyrem treats narcolepsy, it might modulate the action of the inhibitory neurochemical GABA. It also has the potential to cause addiction, leading to efforts to develop less risky treatments for narcolepsy patients.
A different narcolepsy drug developed by the French pharmaceutical company Bioprojet SCR and its US partner Harmony Biosciences was recently approved by the FDA. The drug has a different mechanism of action to Xyrem, and hasn’t been shown to be addictive. The UK companies Orexia and Inexia are also developing alternative treatments for narcolepsy. Their drugs are designed to mimic a protein called orexin, which controls wakefulness.
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