This study is a phase II, randomized, double-blind, placebo-controlled, parallel group study in subjects with rheumatoid arthritis (RA) on stable doses of Enbrel. Subjects with an adequate response to Enbrel will be enrolled into the study. Subjects will be withdrawn from their Enbrel and randomized to receive 28 days of dosing with either GSK706769 or placebo followed by 28 days off-drug. This study is exploring a novel therapeutic paradigm for RA, remission maintenance. In such an approach, remission is induced and then the inducing agent is stopped and a maintenance agent is added. The clinical benefit would be derived from the fact that the remission agent may be easier to take (e.g. oral rather than parenteral), more durable in its maintenance of remission, and/or safer (e.g. no TB reactivation). This study directly explores remission maintenance. Specifically, in a randomised, double blind, placebo controlled study, RA patients in remission through an adequate response to Enbrel will be recruited. Enbrel has been selected as it has a relatively short half life and therefore it is more likely patients treated with placebo may have a higher incidence of relapse after 28 days than with other anti-TNF treatments. After withdrawal of Enbrel (and possibly other oral DMARDs), subjects will be randomised to receive GSK706769 or placebo for 28 days followed by a period of 28 days off treatment. It is hypothesized that GSK706769 will prevent any CCR5+ cells from returning into the synovium, thereby resulting in maintenance of the efficacy induced by Enbrel. In the placebo group, CCR5 cells may re-populate the synovium resulting in increased inflammation. Patients experiencing increased disease activity will be able to withdraw from the study and resume standard of care.
The purpose of this study is to determine if GSK706769 can maintain clinical remission established by Enbrel after withdrawal of Enbrel in rheumatoid arthritis patients.