To assess whether the anti-inflammatory effects of rosiglitazone result in improvements in Rheumatoid Arthritis symptoms in patients for whom their existing Disease Modifying Anti-Rheumatic Drug (DMARD) treatment does not give adequate relief.

Inclusion Criteria:

• Rheumatoid Arthritis insufficiently controlled by existing disease-modifying anti-rheumatic drugs
• Subjects will have at least 6 swollen joints plus 2 of the following: 6 tender joints (of 28 joints); early morning stiffness lasting more than 30 minutes; ESR greater or equal to 28mm/h
• must be receiving a stable dose of disease-modifying anti-rheumatic therapy for at least 2 months prior to participating in the study.

Exclusion criteria:

• Women who are lactating, pregnant, or planning to become pregnant during the course of the study including 30 days following conclusion of study medication
• Systolic blood pressure (SBP) >165 mmHg or diastolic blood pressure (DBP) >95 mmHg while receiving optimal antihypertensive therapy
• Any clinically significant abnormality identified on the screening physical exam, laboratory tests, or ECG, which in the judgement of the Investigator makes the subject unsuitable for inclusion in the study
• a history of alcohol abuse within the past 3 years or consumes >3 units per day for males and >2 units per day for females or has a history of cirrhosis or stigmata of chronic liver disease
• a history of liver disease or has alanine aminotransferase (ALT) or aspartate aminotransferase (AST) levels >2.5 times upper limit of normal and total bilirubin levels greater than 1.5 times the upper limit of normal (unless associated with predominantly indirect bilirubin or Gilbert's syndrome) at screening
• using glucocorticoid at doses >10 mg/day currently or within the last 3 months or may be expected to do so during the course of the study
• The subject's dose of NSAIDs, COX-2 inhibitors or glucocorticoids has changed at any time during the past 2 weeks prior to screening or may be expected to change during the course of the study
• The subject's dose or treatment with a statin has changed at any time during the past 3 months prior to screening or may be expected to change during the course of the study
• a history of renal disease or has serum creatinine = 132mol/L for males and =130mol for females
• has diabetes mellitus that requires medication or hyperglycaemia with a HbA1c of >7%
• History of new cardiovascular event within the last 6 months (i.e., intervention, percutaneous coronary intervention, vascular surgery, acute coronary syndrome [non Q-wave myocardial infarction, Q-wave myocardial infarction, unstable angina) or significant arrhythmia; or major intervention (e.g., cardiac surgery or angiography plus stenting) scheduled
• Concurrent or past medical history of congestive heart failure or pulmonary oedema
• A presence of severe peripheral oedema or a medically serious fluid-related event
• has significant cardiac, pulmonary, metabolic, renal, hepatic, gastrointestinal or immunological conditions that, in the opinion of the Investigator and/or GSK medical monitor, places the subject at an unacceptable risk as a participant in this trial
• a history of malignancy in the last 5 years, except for surgically cured basal cell carcinoma (>2 years prior to first dosing)
• a history of HIV, or chronic hepatitis B or positive C serology
• a history of drug abuse
• has participated in a clinical trial within the 3 months before the start of the study for non-biological therapy; or within 6 months of a biological therapy
• on a biological therapy or has received biological therapy within 6 months prior to screening
• has donated blood in excess of 500 mL within 56 days prior to dosing
• The subject is at risk of non-compliance in following directions or adhering to study restrictions
• a history of drug or other allergy, which, in the opinion of the physician responsible, contraindicates their participation
• has anaemia defined by haemoglobin concentration <11 g/dL for males or <10 g/dL for females](streamdown:incomplete-link)

Patient-level data for this study will be made available through www.clinicalstudydatarequest.com following the timelines and process described on this site.