Phase I Study of GW856553 (Losmapimod)

Inclusion Criteria: * Healthy as determined by a responsible and experienced physician, based on a medical evaluation including medical history, physical examination, laboratory tests and cardiac monitoring. A subject with a clinical abnormality or laboratory parameters outside the reference range for the population being studied may be included only if the Investigator and the GSK Medical Monitor agree that the finding is unlikely to introduce additional risk factors and will not interfere with the study procedures. * Male or female between 20 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: Non-childbearing potential defined as pre-menopausal females. * Male subjects with female partners of child-bearing potential must agree to use one of the contraception methods. This criterion must be followed from the time of the first dose of study medication until follow-up visit. * Body weight \>= 45 kg and BMI within the range 18.5 - 29.0 kg/m2 (inclusive). * Japanese defined as being born in Japan, having four ethnic Japanese grandparents, holding a Japanese passport or identity papers and being able to speak Japanese. Japanese subjects must not have lived outside of Japan for more than 10 years. * ALT, alkaline phosphatase and bilirubin \<= 1.5xULN (isolated bilirubin \>1.5xULN is acceptable if bilirubin is fractionated and direct bilirubin \<35%). * Single QTc, QTcB or QTcF \< 450 msec. Exclusion Criteria: * A positive pre-study Hepatitis B surface antigen or positive Hepatitis C antibody result within 3 months of screening * Current or chronic history of liver disease, or known hepatic or biliary abnormalities (with the exception of Gilbert's syndrome or asymptomatic gallstones). * A positive pre-study drug/alcohol screen. * A positive test for HIV antibody. * History of regular alcohol consumption within 6 months of the study defined as: an average weekly intake of greater than 21 units for men and 14 for women or an average daily intake of greater than 3 units. One unit is equivalent to a 285 mL glass of full strength beer or 425 mL schooner of light beer or 1 (30 mL) measure of spirits or 1 glass (100 mL) of wine (NHMRC Guidelines \[NHMRC, 2009\]) * 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). * Exposure to more than four new chemical entities within 12 months prior to the first dosing day. * Unable to refrain from the use of prescription or non-prescription drugs, including vitamins, herbal and dietary supplements (including St John's Wort) within 7 days (or 14 days if the drug is a potential enzyme inducer) or 5 half-lives (whichever is longer) prior to the first dose of study medication, unless in the opinion of the Investigator and GSK Medical Monitor the medication will not interfere with the study procedures or compromise subject safety. * History of sensitivity to any of the study medications, or components thereof or a history of drug or other allergy that, in the opinion of the investigator or GSK Medical Monitor, contraindicates their participation. * Where participation in the study would result in donation of blood or blood products in excess of 500 mL within a 56 day period. * Pregnant females as determined by positive urine hCG test at screening or prior to dosing. * Lactating females. * Unwillingness or inability to follow the procedures outlined in the protocol. * Subject is mentally or legally incapacitated. * History or regular use of tobacco- or nicotine-containing products within 6 months prior to screening.