A Study to Assess the Safety & Interaction Between GW679769, Dexamethasone, & Ondansetron When Taken by Healthy Adults

Inclusion Criteria: * Healthy adult males or females * Age: 18 to 55 years, inclusive * A female subject who is non-childbearing potential or using acceptable contraceptive methods. * Adequate organ systems function * Able to swallow and retain oral medication * Able to understand and comply with protocol requirements and instruction and is likely to complete the study. Exclusion Criteria: * Cannot participation if subject has a clinically relevant abnormality, medical condition, or circumstance that makes them unsuitable for the study per the study doctor. * History of drug or other allergy which, in the opinion of the Investigator, contraindicates participation. * Use of an investigation drug within 28 days or 5 half-lives. * Blood donation in excess of 500mL within 56 days prior to dosing or intends to donate within 30 days of the post-treatment follow-up visit. * Presence of or suspected iron deficiency * Positive stool for occult blood * Female subject who is lactating * Positive urine drug screen * Positive for HIV antibody, hepatitis C antibody or hepatitis B surface antigen * Use of tobacco-containing products within the past 12 months prior to screening * History of drug or alcohol abuse or dependence within 6 months of screening * History or presence of uncontrolled emesis * Positive purified protein derivative (PPD) skin test for tuberculosis