The purpose of this study is to better define the absorption and elimination pathways, and circulating metabolites of Pitolisant at steady state using Pitolisant radiolabelled, in healthy CYP2D6 genotyped male subject.

Inclusion Criteria:

• Healthy males aged 30 to 65 years.
• Body mass index 18.0 to 35.0 kg/m2.
• Genotyped with regard to their CYP2D6 status.

Exclusion Criteria:

• Participation in a clinical research study within the previous 3 months
• Radiation exposure, including that from the present study, excluding background radiation but including diagnostic x-rays and other medical exposures, exceeding 5 mSv in the last 12 months or 10 mSv in the last 5 years. No occupationally exposed worker, as defined in the Ionising Radiation Regulations 1999, shall participate in the study.
• Regular alcohol consumption in males >21 units per week.
• Current smokers and those who have smoked within the last 12 months.
• Evidence of renal impairment at screening, as indicated by an estimated creatinine clearance (CLcr) of <90 mL/min using the Cockcroft-Gault equation.
• Use of CYP2D6 inhibitors or inducers in the 28 days prior to IMP administration