Inclusion Criteria:

• Healthy as determined by a responsible physician, based on a medical evaluation including medical history, physical examination, laboratory tests and ECG.
• Male or female between 18 and 65 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 with a documented tubal ligation or hysterectomy; or postmenopausal defined as 12 months of spontaneous amenorrhea
  • Child-bearing potential and agrees to use one of the contraception methods listed in the protocol for an appropriate period of time (as determined by the product label or investigator) prior to the start of dosing to sufficiently minimize the risk of pregnancy at that point. Female subjects must agree to use contraception until the follow-up visit.
• Body weight >= 50 kg and BMI within the range 19 - 30 kg/m2 (inclusive).
• Capable of giving written informed consent, which includes compliance with the requirements and restrictions listed in the consent form.
• QTcB or QTcF < 450 msec; or QTc < 480 msec in subjects with Bundle Branch Block.

Exclusion Criteria:

• A positive pre-study Hepatitis B surface antigen or positive Hepatitis C antibody result within 3 months of screening.
• 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.
• History of drug abuse.
• 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.
• History of anaphylaxis, anaphylactoid reactions and severe allergic responses.
• History of adult asthma manifested by bronchospasms in the past 6 months or currently taking regular anti-asthmatic medication.
• Currently receiving oral or injectable strong CYP3A4 inhibitor(s).
• Consumption of grapefruit or grapefruit juice within 7 days prior to first dose of study medication.
• 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 serum hCG test at screening.
• Lactating females.
• Unwillingness or inability to follow the procedures outlined in the protocol.