A Study of TAK-360 in Adults With Narcolepsy Type 1 (Narcolepsy With Cataplexy)

Key Inclusion Criteria: 1. The participant has a body mass index within the range 18 to 40 kilograms per meter square (kg/m\^2) (inclusive). 2. The participant has an International Classification of Sleep Disorders, Third Edition (ICSD-3) or ICSD-3 Text Revision diagnosis of NT1. Key Exclusion Criteria: 1. The participant has a current medical disorder, other than narcolepsy with cataplexy, associated with excessive daytime sleepiness. 2. The participant: (a) has a history of myocardial infarction; (b) has a history of clinically significant thyroid disease, coronary artery disease, cardiac rhythm abnormality or heart failure. 3. The participant has a clinically significant history of head injury or head trauma. 4. The participant has a history of epilepsy, seizure, or convulsion (except for a single febrile seizure in childhood). 5. The participant has a history of cerebral ischemia, transient ischemic attack (\<5 years from screening), intracranial aneurysm, or arteriovenous malformation. 6. The participant has a history of cancer in the past 5 years (does not apply to participants with carcinoma in situ that has been resolved without further treatment or basal cell carcinoma; these participants may be included after approval by the medical monitor). 7. The participant has a positive test result for hepatitis B surface antigen, hepatitis B core antibody, hepatitis C virus antibody, or human immunodeficiency virus (HIV) antibody/antigen at screening. 8. The participant plans to participate in any other interventional trial while participating in TAK-360-2004 or has previously participated in another part in TAK-360-2004. 9. The participant has a known hypersensitivity to any component of the formulation of TAK-360 or related compounds.