GW679769 may affect liver enzymes that metabolize dexamethasone and ondansetron. This study is designed to test the safety and the extent of the GW679769 affect on dexamethasone and ondansetron levels in humans.

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