The Effect of Rifampin on the Metabolism of Istradefylline in Healthy Volunteers.

Effect of a Strong Enzyme Inducer, Rifampin, on the Single-Dose Pharmacokinetics of Istradefylline in Healthy Subjects

The purpose of this study is to test whether Rifampin affects blood levels of istradefylline in humans. Rifampin could possibly decrease istradefylline levels.

Inclusion Criteria:

• Healthy non-smoking male and post-menopausal female subjects
• Body Mass Index: 18.0-35.0 kg/m2, inclusive
• Subjects must not be taking drugs that are moderate to potent inhibitors of CYP3A4 or CYP1A2.
• Subjects without clinically significant medical history in the judgment of the investigator
• Subjects without clinically significant laboratory or ECG abnormalities

Exclusion Criteria:

• Females that are pregnant or lactating
• Administration of an investigational drug within 30 days or 5 elimination half-lives of such investigational drug, whichever is longer, prior to study drug administration, or planned administration of another investigational product or procedure during the subject's participation in this study;
• Known history of treatment for drug or alcohol addiction within the previous 12 months;
• Subjects with an average alcohol intake of more than 2 units per day or 14 units per week up to 48 hours prior to the istradefylline dose on Day 1. One unit of alcohol is ½ pint of beer (285 mL) or 1 glass of spirits (25 mL) or 1 glass of wine (125 mL);
• Donated or lost > 500 mL of blood within 3 months prior to istradefylline dose on Day 1 of Period 1;
• Positive test results for human immunodeficiency virus (HIV) or Hepatitis B surface antigen, or Hepatitis C;
• Positive test results for drugs of abuse at screening;
• Unable, or unwilling to tolerate multiple venipunctures;
• Difficulty fasting or eating the standard meals that will be provided;
• Use of tobacco or nicotine-containing products within 90 days of the study start to the Follow-up visit