Takeda Pharmaceutical’s experimental narcolepsy drug has significantly improved outcome for patients in late-stage clinical trials, and could become the first treatment to target the root cause of the chronic sleep disorder.

Patients who took the drug, called oveporexton, for 12 weeks experienced increased daytime alertness, fewer episodes of sudden muscle tone loss, and an overall improvement in quality of life compared to those given a placebo. The findings were part of studies published at World Sleep Congress held in Singapore, which runs through Sept. 10.

While no serious side effects were reported, the most common adverse events included insomnia as well as increased urinary urgency and frequency, according to the studies.