A Study to Investigate the Ability of GSK706769 to Maintain Clinical Remission After Withdrawal of Enbrel in Rheumatoid Arthritis Patients

Inclusion Criteria: * Male or female over 18 years of age, at the time of signing the informed consent. * A female subject is eligible to participate if she is of child-bearing potential and agrees to use one of the contraception methods listed in the protocol for an appropriate period of time Female subjects must agree to use contraception until 4 days post-last dose. * Body weight greater than or equal to 50 kg and BMI within the range 19 - 32 kg/m2. * The subject has a diagnosis of RA according to the revised 1987 criteria of the American College of Rheumatology (ACR) and has been treated with an anti TNF-alpha agent for \< 2 years. * The subject is taking Enbrel for at least 6 months prior to enrollment. * The subject is willing to stop taking Enbrel for 56 days. * The subject is in clinical remission, defined as DAS28 less than or equal to 2.6 and has been for the preceding 6 months. * Capable of giving written informed consent, which includes compliance with the requirements and restrictions listed in the consent form. * Average QTcB or QTcF \< 450 msec; or QTc \< 480 msec in subjects with Bundle Branch Block. * AST and ALT \< 2xULN; alkaline phosphatase and bilirubin less than or equal to 1.5xULN (isolated bilirubin \>1.5xULN is acceptable if bilirubin is fractionated and direct bilirubin \<35%). Exclusion Criteria: * The subject is using oral prednisolone at doses \> 10mg/day. * The subject's NSAID or glucocorticoid dosing regimen has changed during the 4 weeks prior to randomisation. * The subject's receiving DMARDs other than Enbrel and methotrexate. * The subject's current methotrexate regimen has changed significantly (i.e. likely to impact disease activity during the study period) within the 3 months prior to dosing e.g. changes in dose of greater than 2.5mg. * Use of CYP3A4 inhibitors/inducers within 14 days prior to dosing and CYP3A4 substrates with a narrow therapeutic index within 7 days prior to dosing. * 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. * Absolute neutrophil count \< 1500/ul. * History of sensitivity to the study medication, or components thereof or a history of drug or other allergy that contraindicates their participation. * 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 screen, unless the subject is receiving a prescribed medication that could give a positive in the drug screen and prior to the screen being sent the medication has been discussed and pre-approved by the medical monitor. * A positive test for HIV antibody. * History of regular alcohol consumption within 6 months of the study defined by the protocol. * The subject has an acute infection or a history of repeated or chronic infections. * The subject has significant cardiac, pulmonary, metabolic, renal, hepatic or gastrointestinal conditions that in the opinion of the investigator and/or medical monitor, places the subject at an unacceptable risk as a participant in this trial. * Subjects with autoimmune hemolytic anemia or G6PD deficiency. * Malignancy in the past 2 years, except for adequately treated non-invasive cancers of the skin. * Where participation in the study would result in donation of blood or blood products in excess of 500 mL within a 56 day period. * Lactating females. * Unwillingness or inability to follow the procedures outlined in the protocol. * Subject is mentally or legally incapacitated. * Consumption of grapefruit, grapefruit juice or grapefruit hybrids within 7 days prior to the first dose of study medication.