The purpose of this study is to assess the pharmacokinetics of NKTR-118 in patients with impaired hepatic function versus subjects with normal hepatic function.

Inclusion Criteria:

• Males or females aged 18 years or more with a weight of at least 50 kg and BMI between 18 and 40 kg/m2, inclusive.
• Negative screen for human immunodeficiency virus (HIV)
• For subjects with normal hepatic function, negative results for serum hepatitis B (HBV) surface antigen, HCV antibody, and HIV

Exclusion Criteria:

• Plasma or blood product donation within 1 month of screening or any blood donation/blood loss greater than 500 mL during the 3 months prior to screening.
• History of severe allergy/hypersensitivity or ongoing allergy/hypersensitivity
• Known or suspected history of drug/chemical abuse within the past 2 years as judged by the Investigator.
• Subjects with a history of surgery on the gastrointestinal tract.
• For patients with hepatic impairment, fluctuating or rapidly deteriorating hepatic function as indicated by clinical and/or laboratory signs of hepatic impairment (e.g. advanced ascites, infection of ascites, fever, or active gastrointestinal bleeding).