HRH3 and narcolepsy: In the 1st phase 2 study (Study 1) for patients with narcolepsy, the dose was decided based on the result of a phase 1 study and nonclinical studies, and in the 2nd phase 2 study (Study 2), the dose was chosen according to the results of the histamine H3 receptor occupancy study using positron emission tomography (PET) ligand on healthy subjects [9].