This study is designed to determine the pharmacokinetics of favipiravir in volunteers with hepatic impairment and in healthy control volunteers.

Inclusion Criteria:

• Hepatically impaired groups:

  • Agree to doctor approved birth control methods from Day 1 until 3 months following the final dose of study drug.
  • Have mild hepatic impairment (Child-Pugh Clinical Assessment Score Grade A, score 5 6) or moderate hepatic impairment (Child-Pugh Clinical Assessment Score Grade B, score 7-9) or severe hepatic impairment (Child-Pugh Clinical Assessment Score Grade C, score 10-15);

• Control group

  • Agree to doctor approved birth control methods from Day 1 until 3 months following the final dose of study drug.
  • Healthy as determined by medical history, physical exam, vital signs, ECGs, and clinical laboratory tests.

Exclusion Criteria:

• Hepatically impaired groups:

  • Have used any drugs known to significantly affect hepatic metabolism within 28 days, or is unable or unwilling to forgo the use of such products throughout the study;
  • Have any acute or unstable condition or disease, other than impaired hepatic function, as determined by medical history, physical exam, ECG and clinical laboratory tests;
  • Known ongoing alcohol and/or drug abuse within 1 month
  • Any evidence of progressive worsening liver function disease as indicated by laboratory values;
  • Have had an acute flare of hepatitis A or B within 6 months;
  • Have acute, fulminant alcoholic hepatitis, determined either clinically or by histology;
  • Have a history of hepatoma or metastatic disease of the liver;

• Control group:

  • Have used any drugs known to significantly affect hepatic metabolism within 28 days, or is unable or unwilling to forgo the use of such products throughout the study;
  • Have a history or presence of clinically cardiovascular, dermatologic, endocrine, gastrointestinal, hematologic, hepatic, immunologic, neurologic, oncologic, psychiatric, pulmonary, or renal disease or any other condition.