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.
