This trial was supporting the development of an asset which was terminated, thus the data from the study were no longer required.

This longitudinal, prospective study aims to establish the magnitude and time course of changes in intestinal permeability; establish the optimal method for assessment of intestinal permeability in thermally injured participants: describe the participant population most likely to benefit from a new medicinal product which could prevent changes in intestinal permeability; and improve our understanding of the links between intestinal damage, changes in the gut microbiome and microbial translocation to the systemic circulation following thermal injury. The key factors of interest in this study are to understand the impact of thermal injury on intestinal permeability in thermally injured participants compared to healthy participants; and to understand the changes in intestinal permeability over time. Approximately 15 eligible healthy participants and 25 thermally injury participants will be included. The sugar test material (STM) comprises of Lactulose, Mannitol and Sucralose and will be intermittently administered enterally to all the participants. The full duration of the study for healthy participants will be approximately two weeks and 6 months for thermally injured participants. In order to enter this study thermally injured participants will be required to co-enroll in this study and an allied study entitled: A Multi-center, Prospective Study to Examine the Relationship between Neutrophil Function and Sepsis in Adults and Children with Severe Thermal Injury (SIFTI-2). (reference number IRAS ID: 200366).

Inclusion Criteria:

For Healthy participants:

• Males or females must be greater than or equal to 18 years of age at the time of signing informed consent.
• Participants who are healthy as determined by the investigator following medical evaluation including medical history, physical examination, and laboratory tests.
• A female participant is eligible to participate if she is not pregnant (negative pregnancy testing at screening or Day 1 as needed) and not breastfeeding.
• Capable of giving signed informed consent.

For Thermally injured participants:

• Participants must be greater than or equal to 18 years of age.
• Participants who have sustained a burn (thermal injury) with a Total Burn Surface Area (TBSA) greater than or equal to 15 percent.
• Admission to the burn center (study site) less than or equal to 24 hours following injury.
• Able to take enteral fluids either orally or via a nasogastric tube (depends on facial burn damage).
• A female participant is eligible to participate if she is not pregnant (negative pregnancy testing at study entry) and not breastfeeding.

Exclusion Criteria

For Healthy participants:

• Healthy participants are excluded from this study if they are receiving anti-coagulation therapy.
• Pregnancy or breastfeeding.
• A body mass index greater than 34 kilogram per meter square (kg/m^2).
• An active history of alcohol dependency.
• History of sensitivity to any of the STM, or components thereof or a history of drug or other allergy that, in the opinion of the Investigator and/or GlaxoSmithKline (GSK) Medical Monitor, contraindicates their participation.
• A positive pre-study Hepatitis B surface antigen or positive Hepatitis C antibody and confirmatory Hepatitis C Polymerase Chain Reaction (PCR) result within 3 months of screening.
• A positive pre-study urine drug/alcohol screen.
• A positive test for Human Immuno-deficiency Virus (HIV) antibody.
• Participants unable to swallow large capsules (the capsules will be shown to participants at screening).
• Galactosaemia or severe lactose intolerance.
• Use of an antibiotic 2 weeks prior to study start (administration of the STM).
• Gastroenteritis in the 2 weeks prior to study start (administration of the STM).

For thermally injured participants:

• Chemical or electrical burn.
• Multiple traumatic injuries with an Injury Severity Score (ISS) more than or equal to 16.
• Participants received substantial undocumented management prior to arrival at the study site (burn center) e.g. from paramedics or in a local accident and emergency department.
• Systemic corticoidsteroid use.
• Intravenous (IV) Mannitol use.
• HIV infection.
• Viral Hepatitis B or C infection.
• Gastrointestinal disease (e.g. inflammatory bowel disease) which may affect intestinal permeability.
• Previous bowel resection (e.g. hemicolectomy, small bowel resection).
• Galactosaemia or severe lactose intolerance.
• Bowel obstruction.
• Renal dysfunction requiring renal replacement therapy (end-stage renal failure prior to thermal injury).
• Active autoimmune disease and receiving immunomodulatory therapy e.g. rheumatoid arthritis anti-Tumor Necrosis Factor (TNF).
• Active chemotherapy for cancers or immunoremittive therapies (prednisolone, Adalimumab) within 60 days of thermal injury.
• Premorbid conditions of malignancy currently under treatment.
• Previous bilateral lower extremity amputation.
• Decision not to treat the participant due to futility.

One participant from healthy participants was excluded due to protocol deviation.

Serious adverse events (SAE) and Non-SAE were collected from Day 1 up to 6 months for thermal injury participants and SAE and Non-SAE were collected from Day 1 up to Day 15 for healthy participants. Safety Population comprised of all participants who received at least one dose of STM and have at least one post-dose safety assessment.

Death is typically associated with the disease under study and were not reported as SAEs but instead were recorded drug related events (DREs). In thermally injured participants DREs are common and can be serious/life threatening: Deterioration of condition; Death (may be expected in burns of a large surface area); Prolongation of hospital stay; Persistent or significant disability or incapacity.