The purpose of this study is to assess the tolerability of BIA 9-1067 after multiple rising dose regimens of BIA 9-1067.

Single centre, double-blind, randomised, placebo-controlled study of four dosage regimens of BIA 9-1067 in four groups of healthy male volunteers. In each group, the study will consist of an once-daily (o.d.) 8-day multiple-dose period. Progression to the next dose level will only occur if the previous dose level was considered to be safe and well tolerated. An appropriate interval (will separate the investigation of doses to permit a timely review and evaluation of safety data prior to proceeding to a higher dose level.

Inclusion Criteria:

1. A signed and dated informed consent form before any study-specific screening procedure is performed.
2. Aged between 18 and 45 years, inclusive.
3. Healthy as determined by the investigator on the basis of medical history, physical examination, clinical laboratory test results, vital signs and digital 12-lead electrocardiogram (ECG).
4. Nonsmoker or smoker of fewer than 10 cigarettes per day as determined by history. Must be able to abstain from smoking during the inpatient stay.

Exclusion Criteria:

1. Any significant cardiovascular (e.g. hypertension), hepatic, renal, respiratory (e.g. childhood asthma), gastrointestinal, endocrine (e.g. diabetes, dyslipidemia), immunologic, dermatological, haematological, neurologic, or psychiatric disease.
2. Acute disease state (e.g., nausea, vomiting, fever, diarrhoea) within 7 days before study day 1.
3. History of drug abuse within 1 year before study day 1.
4. History of alcoholism within 1 year before day 1. Consumption of more than 50 g of ethanol per day (12.5 cL glass of 10° [10%] wine = 12 g; 4 cL of aperitif, 42° [42%] whiskey = 17 g; 25 cL glass of 3° [3%] beer = 7.5 g; 25 cL glass of 6° [6%] beer = 15 g
5. Have previously received BIA 9-1067.
6. Positive serologic findings for human immunodeficiency virus (HIV) antibodies, hepatitis B surface antigen (HBsAg), and/or hepatitis C virus (HCV) antibodies.
7. Positive findings of urine drug screen (eg, amphetamines, barbiturates, benzodiazepines, cannabinoids, cocaine, methadone, opiates, MDMA [3,4-methylenedioxy-methamphetamine; ecstasy]).
8. History of any clinically important drug allergy.
9. Prohibited Treatments: use of any investigational drug within 90 days or prescription drug within 30 days before investigational medical product (IMP) administration.
10. Consumption of any caffeine-containing products (e.g., coffee, tea, chocolate, or soda) in excess of 6 cups per day (or equivalent), of grapefruit, grapefruit-containing products, or alcoholic beverages within 24 before study day 1.
11. Use of any over-the-counter drugs including herbal supplements (except for the occasional use of acetaminophen [paracetamol], aspirin and vitamins ≤100% recommended daily allowance) within 7 days before IMP administration.
12. Donation of blood (ie 450 ml) within 90 days before study day 1.