The purpose of this study is to assess the potential effects of ketoconazole on the pharmacokinetics of ibrutinib in healthy participants.

This is a single-center, open-label (all people know the identity of the intervention), sequential design study in healthy men. All participants will receive ibrutinib on Day 1 and ibrutinib in combination with ketoconazole on Day 7. Food will be restricted from the evening before dosing until 4 hours after dosing on Days 1 and 7. Following an overnight fast, ketoconazole will be given on Days 4 to 6, 1 hour prior to ibrutinib dosing on Day 7, and again on Days 8 and 9. All ibrutinib and ketoconazole doses will be administered with water. The participants will leave the study center on Day 10.

Inclusion Criteria:

• Body mass index (BMI) between 18 and 30 kg/m2, and body weight not less than 50 kg
• Blood pressure between 90 and 140 mmHg systolic, inclusive, and no higher than 90 mmHg diastolic
• Non-smoker
• Must agree to use an adequate contraception method during the study and minimally 3 months after the last dose of ibrutinib, and to not donate sperm during the study and for 3 months after receiving the last dose of study drug
• Signed an informed consent document

Exclusion Criteria:

• History of or current clinically significant medical illness
• Clinically significant abnormal physical examination, vital signs or electrocardiogram (ECG)
• Clinically significant abnormal values for laboratorial tests
• Use of any prescription or nonprescription medication, except for acetaminophen, within 3 days before the first dose of the study drug is schedule
• History of, or a reason to believe a participant has a history of drug or alcohol abuse within the past 2 years