The purpose of this study is to characterize the pharmacokinetics (what the body does to the study medication) of JNJ-38518168 at approximately steady-state (stable medication levels) after administration of multiple oral 30 mg doses of JNJ-38518168 to participants with mild or moderate hepatic (liver) impairment (abnormal function) compared with participants with normal hepatic function.

This is an open-label (both [participants and investigator] know what treatment participants will receive) and multicenter study. The study consists of 3 phases: a screening phase (approximately 3 weeks), a treatment phase (from day -2 [2 days before the administration of study medication] to Day 18), and an end-of-study phase (7 to 10 days after the last dose of study medication). Approximately 24 participants (participants with mild hepatic impairment, moderate hepatic impairment, and normal liver function) will receive JNJ-38518168 for 14 days. Hepatic impairment will be evaluated according to Child-Pugh score. It consists of 5 clinical measures (amount of ascites [an abnormal accumulation of fluid in the abdomen], total bilirubin [mg/dL], albumin [g/dL], international normalized ratio, and degree of encephalopathy [abnormal functioning of the brain]). Each is scored from 0 (less severity) to 3 (highest severity). Total Child-Pugh score is the sum of all subscores and is graded as: mild (5-6 points), moderate (7-9 points), and severe (10-15 points). Safety will be evaluated by the assessment of adverse events, clinical laboratory tests, vital signs, body weight, physical examination, and 12-lead electrocardiogram which will be monitored at various timepoints throughout the study. The total duration of study participation for each participant is approximately 6 weeks.

Inclusion Criteria:

• Have normal liver function for the normal hepatic function group
• Have mild or moderate liver diseases as defined by the Child-Pugh Classification and be clinically stable overall for the mild or moderate liver disease groups
• Doses of drugs used to treat other illnesses or conditions related to liver disease must be stable for at least 4 weeks before the first dose of study medication with the exception of thyroid replacement hormone, in which case the dose must be stable for 3 months before the first dose of study medication. Doses of these drugs must also be stable during the course of the study
• If an illness with a fever occurs within one week of the start of dosing, dosing must be postponed until the body temperature is normal for at least 72 hours
• Participants must agree to use one of the contraception methods defined in the protocol

Exclusion criteria:

• Hepatic insufficiency secondary to autoimmune hepatitis or obstructive liver disease
• Allergy to heparin or history of heparin-induced thrombocytopenia
• All participants must have a negative human immunodeficiency virus test. Participants with normal liver function must test negative for hepatitis B and hepatitis C
• Severe ascites (an abnormal accumulation of fluid in the abdomen) or severe pleural effusion (fluid around the lungs)