This is a two-part study which will evaluate the PK, safety, and tolerability of a single 1500 milligram (mg) oral dose of gepotidacin in subjects with normal hepatic function and in subjects with mild, moderate, and severe hepatic impairment. In Part 1, subjects with moderate hepatic impairment and subjects with normal hepatic function will be enrolled. Matching subjects with normal hepatic function in Part 1 (Group D), will be enrolled following the completion of all Day 3 assessments of the respective matched, hepatically impaired subject. In Part 2, subjects with mild (optional) and severe hepatic impairment and subjects with normal hepatic function will be enrolled concurrently based on the PK, safety, and tolerability data of Part 1. Subjects with mild hepatic impairment, may be studied if there is a significant difference in PK between subjects with moderate hepatic impairment and subjects with normal hepatic function. Subjects with severe hepatic impairment, will be studied in Part 2, provided that, the PK objectives are achieved in Part 1. A totals of 48 subjects, are planned to be enrolled in the study. The study duration is approximately of 44 days from Screening to Follow-up visit. The results from this study will enable the development of appropriate dosing recommendations in subjects with impaired hepatic function.

Inclusion Criteria:

• Subjects must be 18 to 80 years of age inclusive, at the time of signing the informed consent.
• Healthy subjects must be in clinically stable health as determined by the investigator based on medical history, clinical laboratory results (serum chemistry, hematology, urinalysis, and serology), vital sign measurements, 12-lead ECG results, and physical examination findings.
• Hepatically impaired subjects must have chronic (>6 months), stable (no acute episodes of illness within the previous 1 month prior to screening due to deterioration in hepatic function) hepatic insufficiency with features of cirrhosis due to any etiology. Subjects must also remain stable throughout the Screening period.
• Hepatically impaired subjects, will be classified, using the Child-Pugh classification system. Subjects must have, a Child-Pugh score, of 5 to 6 (mild hepatic impairment), 7 to 9 (moderate hepatic impairment), or 10 to 15 (severe hepatic impairment), with known medical history of liver disease (with or without a known history of alcohol abuse), and previous confirmation of liver cirrhosis by liver biopsy or other medical imaging technique (including laparoscopy, computed tomography scan, magnetic resonance imaging, or ultrasonography) associated with unambiguous medical history. If imaging study, or biopsy is not available, then the subject should have one of the following: Physical findings such as hepatomegaly, ascites, palmar erythema, spider angiomata, abdominal venous collaterals, gynecomastia, or other physical manifestations of hepatic disease Or Laboratory findings: ALT or AST elevation (> upper limit of normal [ULN]), alkaline phosphatase, or total bilirubin, or international normalized ratio (INR) elevation (>ULN) or an albumin value that is below the lower limit of normal laboratory reference range.
• Subjects with hepatic impairment may be taking medications, which in the opinion of the investigator, are believed to be therapeutic, and these medications should not interfere with the conduct of the study. Subjects with hepatic impairment should be on stable regimen of chronic medications for at least 7 days prior to dosing until completion of the Follow-Up Visit.
• Subjects with hepatic impairment must have platelet counts of 30,000 × 109/Liter of blood and have not had any major bleeding episodes within the past 6 months.
• Body weight >=45 kilogram (kg) and body mass index (BMI) within the range 18.5 to 40 kg/meter^2 (inclusive).
• Male subjects must agree to use contraception, as protocol from Day -1 until completion of the Follow-up Visit or, female subject will be eligible to participate if she is not pregnant not breastfeeding, and at least one of the following conditions applied Not a woman of childbearing potential (WOCBP) or A WOCBP who agrees to follow the contraceptive guidance from 30 days prior to study drug administration and until completion of the Follow-up Visit.
• Capable of giving signed informed consent.

Exclusion Criteria:

• Subject has a clinically significant abnormality in past medical history or at the Screening physical examination (excluding hepatic insufficiency and other related medical conditions within the hepatically impaired populations, which should be stable for at least 1 month before study drug administration), that in the investigator's opinion, may place the subject at risk or interfere with outcome variables of the study. This includes, but is not limited to, history or current significant cardiac, renal, neurologic, gastrointestinal, respiratory, hematologic, or immunologic disease.
• Subject has any surgical or medical condition (active or chronic) that may interfere with drug absorption, distribution, metabolism, or excretion of the study drug, or any other condition that may place the subject at risk, in the opinion of the investigator.
• Female subject, has a positive pregnancy test result or is lactating at Screening or upon admission to the clinic.
• Subject has used a systemic antibiotic within 7 days of Screening.
• Subject has a confirmed history of Clostridium (C) difficile infection or a positive C. difficile toxin test, within 2 months before Screening.
• Subject has a history of drug and/or alcohol abuse within 6 months before Screening, as determined by the investigator, or subject has a positive drug screen at Screening or upon admission to the clinic. For subjects with hepatic impairment, and a positive drug screen result related to the use of prescription medications, is allowed per investigator review and approval, and tetrahydrocannabinol use is allowed per investigator review and approval.
• History of sensitivity to any of the study drugs, components thereof, or a history of drug or other allergy that, in the opinion of the investigator or GSK medical monitor, contraindicates their participation.
• History of sensitivity to heparin or heparin-induced thrombocytopenia (if the clinic uses heparin to maintain intravenous cannula patency).
• Subject has used medications known to affect the elimination of serum creatinine (example (e.g); trimethoprim or cimetidine) or competitors of renal tubular secretion (e.g., probenecid) within 30 days before dosing.
• Subject must abstain from taking prescription or nonprescription drugs (including vitamins and dietary or herbal supplements), unless specified, within 7 days (or 14 days if the drug is a potential strong enzyme inducer) or 5 half-lives (whichever is longer) prior to study drug administration until completion of the Follow-Up Visit, unless, in the opinion of the investigator and Sponsor, the medication will not interfere with the study. Any exceptions (including subjects with hepatic impairment that will be on medications during the study), will be discussed with the sponsor or medical monitor on a case-by-case basis and the reasons will be documented.
• Previous exposure to gepotidacin, within 12 months prior to study drug administration.
• Subject has participated in a clinical trial and has received an investigational product within the following time period prior to study drug administration in the current study: 30 days, 5 half-lives, or twice the duration of the biological effect of the investigational product (whichever is longer).
• Subject with normal hepatic function has presence of hepatitis B surface antigen or positive hepatitis C antibody test result at Screening or within 3 months prior to study drug administration. Subject with hepatic impairment has evidence of recent, acute infection with hepatitis B and/or hepatitis C within preceding 6 months. Hepatically impaired subjects with chronic hepatitis B or C (duration >6 months) will be eligible for enrolment.
• A positive test for human immunodeficiency virus antibody.
• Subject must be able to abstain from alcohol and limit use of nicotine and/or nicotine-containing products (up to 5 cigarettes/day is acceptable for subjects with hepatic impairment) for 24 hours before the start of dosing until after collection of the final PK sample. A positive alcohol or cotinine test is not exclusionary for subjects with hepatic impairment.
• Subject has clinically significant abnormal findings in serum chemistry, hematology, or urinalysis results obtained at Screening or Day -1, other than those associated with underlying hepatic conditions or other stable medical conditions consistent with the disease process in subjects with hepatic impairment.
• Subject with normal hepatic function has a baseline corrected QT interval using the Fridericia formula (QTcF) of >450 milliseconds (msec) and subject with hepatic impairment has a baseline QTcF of >480 msec.
• Donation of blood in excess of 500 milliliter (mL) within 12 weeks prior to dosing or participation in the study would result in donation of blood or blood products in excess of 500 mL within a 56-day period.
• Subject is unable to comply with all study procedures, in the opinion of the investigator.
• Subject should not participate in the study, in the opinion of the investigator or Sponsor.
• Subjects with a pre-existing condition (except hepatic impairment) interfering with normal gastrointestinal (GI) anatomy or motility that could interfere with the absorption, metabolism, and/or excretion of the study drugs. Subjects with a history of inflammatory bowel disease should be excluded. Subjects with a history of pepticulceration or pancreatitis within the preceding 6 months of screening, should be excluded.
• Subject with any previous GI surgery (except appendectomy or gall bladder removal >3 months prior to Screening) may be enrolled in this study only if, in the opinion of the investigator and the medical monitor, it is not expected to interfere with the study procedures or to pose an additional safety risk to the subject.
• Subject receiving lactulose who are medically unable to halt lactulose administration from 8 hours before dosing with study drug to 4 hours after dosing with study drug.
• Subjects with clinically active severe encephalopathy (grade 3 or 4) as judged by the investigator or significant central nervous system disease (e.g., dementia or seizures) which the investigator considers will interfere with the informed consent, conduct, completion, or results of this trial or constitutes an unacceptable risk to the subject. Subjects with a prior history of severe encephalopathy, who are currently treated for this condition will receive the appropriate score for encephalopathy.
• Subjects with estimated creatinine clearance (Clcr) <=50 mL/minute (calculated by the Cockcroft-Gault Formula). If the result calculated by Cockcroft-Gault is between 40 and 50 mL/minute, then the site may complete a 24-hour urine collection to more specifically calculate the Clcr. A Clcr value <=50 mL/minute via 24-hour urine collection is also exclusionary.
• History of gastric or esophageal variceal bleeding within the past 6 months and for which varices have not been adequately treated with medication and/or surgical procedures.
• Subjects with electrolyte imbalance whose serum sodium levels are <=125 millimole per Liter (mmol/L); potassium levels are <=2.5 mmol/L; or calcium levels are <=6.1 mmol/L.
• Presence of hepatopulmonary or hepatorenal syndrome.
• Primary cholestatic liver diseases.
• History of liver transplantation or subjects in the severe hepatic impairment group that are expecting a liver transplant during the study participation period.
• Subjects with signs of active bacterial infection (including active spontaneous bacterial peritonitis).
• Subjects with transjugular intrahepatic portosystemic shunt placement within the past 3 months.
• Subjects with unstable cardiac function or subjects with hypertension whose blood pressure, that is not well controlled (based on the investigator's discretion).
• Diabetic subjects whose diabetes that is not controlled (based on the investigator's discretion).

IPD for this study is available via the Clinical Study Data Request site.

IPD is available via the Clinical Study Data Request site (copy the URL below to your browser)

Access is provided after a research proposal is submitted and has received approval from the Independent Review Panel and after a Data Sharing Agreement is in place. Access is provided for an initial period of 12 months but an extension can be granted, when justified, for up to another 12 months.

There will be no masking, as this is an open-label study.