This study is looking at a condition called Narcolepsy without Cataplexy, also known as NT2. This is a sleep disorder where people experience excessive daytime sleepiness and may suddenly fall asleep during the day, but they do not have sudden muscle weakness or loss of muscle control that can occur in other forms of narcolepsy. The treatment being tested is called TAK-360, which is an experimental medication given as a tablet by mouth. Some participants will receive TAK-360 while others will receive placebo. The purpose of this study is to evaluate the safety and tolerability of TAK-360.

During the study, participants will take TAK-360 or placebo for a period of 4 weeks. The study will look at whether any unwanted effects occur during treatment. The study will also measure changes in daytime sleepiness using a questionnaire called the Epworth Sleepiness Scale, which asks about how likely someone is to fall asleep in different situations. Additionally, a test called the Maintenance of Wakefulness Test will be used, which measures how well someone can stay awake in a quiet, comfortable setting. These measurements will be compared between the group taking TAK-360 and the group taking placebo to see if there are any differences.

Participants in this study will be adults between 18 and 70 years old who have been diagnosed with NT2. The study uses a design where neither the participants nor the doctors know who is receiving the actual medication and who is receiving placebo until the study is completed. This helps ensure that the results are measured fairly and without bias. The study will continue for several weeks and will involve regular visits to check on safety and how well the treatment is working.