The purpose of this study is to assess the safety and tolerability of ascending single oral doses of HTC-867 in healthy young and elderly subjects. This study will also evaluate the way the drug enters and leaves the blood and tissues over time and how the drug acts on and in the body in a fasted and fed state.

Inclusion:

1. Men or women of nonchildbearing potential (WONCBP) aged 18 to 50 years or 65 or greater inclusive at screening.

   WONCBP may be included if they are either surgically sterile (hysterectomy and/or oophorectomy) or postmenopausal for ≥1 year (with follicle-stimulating hormone [FSH] ≥38 mIU/mL) and must have a negative pregnancy test result within 48 hours before administration of study drug.

   Women who are surgically sterile must provide documentation of the procedure by an operative report or by ultrasound scan.

   Sexually active men must agree to use a medically acceptable form of contraception during the study and continue it for 12 weeks after study drug administration.

2. Healthy as determined by the investigator on the basis of screening evaluations.

3. The elderly subjects must be generally healthy, but may be enrolled with a stable, chronic illness if it is well controlled and does not interfere with the primary objective of the study. Subjects may be included with clinically important deviations from normal limits in medical history, physical examination findings, vital sign measurements, 12-lead electrocardiograms (ECGs), or clinical laboratory test results that are associated with stable, chronic, and well-controlled medical conditions, so long as those deviations do not meet the stated specific criteria for exclusion

Exclusion:

1. Presence or history of any disorder that may prevent the successful completion of the study.
2. History of cardiac disorders (other than hypertension) including but not limited to valvular disease, congestive heart failure, angina pectoris, myocardial infarction, or arrhythmia.
3. History of vertigo.