Study to Evaluate Fractional Collagen Synthesis Within Keloid Scars and Identify Biomarkers of Keloid Scars

Inclusion Criteria: * Subjects have at least one keloid scar scheduled for removal as part of their normal course of treatment * Males or females aged between 18 and 55 years of age inclusive, at the time of signing the informed consent. * A female subject is eligible to participate if she is of: Child-bearing potential with negative pregnancy test as determined by urine human chorionic gonadotropin (hCG) test at screening, AND; agrees not to become pregnant during the course of the study and for at least 1 month after completion of heavy water consumption; OR is of non child-bearing potential * Male subjects must agree not to father a child during the study and for at least 1 month after completion of heavy water consumption. * Capable of giving written informed consent, which includes compliance with the requirements and restrictions listed in the consent form Exclusion Criteria: * Keloids to be randomised must not have received steroid treatment for at least two months prior to screening. * Evidence of other skin conditions or scarring in the region of keloid scaring (including but not limited to: hypertrophic scars, eczema, psoriasis, etc.) unless the Investigator, in consultation with the GSK medical monitor, agree that the condition is unlikely to introduce additional risk factors and will not interfere with the study procedures. * Current or chronic history of liver disease, or known hepatic or biliary abnormalities (with the exception of Gilbert's syndrome or asymptomatic gallstones). * History of regular alcohol consumption that could preclude safe completion of the study. * History of sensitivity to corticosteroids or history of drug or other allergy that, in the opinion of the investigator or GlaxoSmithKline (GSK) Medical Monitor, contraindicates their participation. * Subjects currently receiving oral corticosteroids. * Subjects with a recent history of tuberculosis (TB) (within last three years). * Evidence or recent history (past two weeks) of any infection (viral, bacterial, fungal, protozoan, or helminthic). * History of recurrent fungal infection. * Lactating females. * The subject has participated in a clinical trial and has received an investigational product within the following time period prior to the first dosing day in the current study: 30 days, 5 half-lives or twice the duration of the biological effect of the investigational product (whichever is longer).