The study investigates how safe ASP3652 is and how well it is tolerated when taken as multiple doses. The study also assesses how quickly and to what extent it is absorbed and eliminated from the body. In addition, the effects of age and gender are investigated.

The study consists of two parts. In Part 1 four dose levels are administered to four separate groups initially. Two additional dosages are then investigated. Subjects receive either a once-daily dose (QD) or twice-daily dose (BID) of ASP3652 or placebo.

Part 2 is performed in one group of elderly healthy male or female (post-menopausal) subjects. Subjects receive either a twice daily dose (BID) of ASP3652 or placebo.

For both parts of the study, the subjects stay in the clinic for one period of 18 days.

This is a Multiple Ascending Dose (MAD) study with two parts. Screening for both parts takes place between Days -28 and -3. Subjects are admitted to the clinic on Day -2, and discharged on Day 16. They return for an End of Study Visit (ESV) between 7 and 14 days after (early) discharge.

Part 1 evaluates the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of ASP3652 following ascending multiple oral doses. The initially planned four dose levels or matching placebo are given to four separate groups. Thereafter two additional dosage levels are further investigated. All groups receive a single dose of ASP3652 administered in the morning of Day 1 and Day 14, and twice-daily doses administered from Day 2 to Day 13 under fasted conditions, except the last group which receives all dosages once daily from Day 1 to Day 14.

Part 2 evaluates the safety, tolerability, PK and PD of ASP3652 following ascending multiple oral doses in healthy elderly male and female subjects. This part contains a single, placebo-controlled group. All subjects receive twice daily doses and administration is based on the results of Part 1.

All subjects in both parts receive training for Neurocognitive Test Battery (NTB) and tests for monitoring of psychotropic effects.

Inclusion Criteria:

• Body Mass Index (BMI) between 18.5-30.0 kg/m2 for both male and female subjects.
• Male subject is non-fertile, i.e. surgically sterilized or practices an adequate contraceptive method to prevent pregnancies.
• Female subject is of non-child bearing potential, i.e. post menopausal, surgically sterilized, hysterectomy in medical history, or practices adequate (double barrier) non-hormonal contraceptive method to prevent pregnancies.

Exclusion Criteria:

• Pregnant or breast feeding within 6 months before screening assessment.
• Presence or history of any clinically significant psychiatric disorder such as mania, depression or schizophrenia.
• Regular use of any inducer of liver metabolism (e.g. barbiturates, rifampin) in the 3 months prior to admission to the Clinical Unit.