Study Comparing Etanercept (ETN) Against a Placebo for Etanercept on a Background Nonsteroidal Anti Inflammatory Drug (NSAIDs) in the Treatment of Early Spondyloarthritis (SpA) Patients Who do Not Have X-ray Structural Changes

This is a two part study. During period one there will be a comparison of Etanercept (ETN) against a placebo with both arms maintaining the background anti inflammatory drug prescribed by their Physician. The hypothesis is that Etanercept will be superior to the placebo arm as determined by the proportion of subjects achieving Assessments in Ankylosing Spondylitis (ASAS)40 improvement at 12 weeks. This will be followed by 92 weeks extension where everyone in the trial receives Etanercept (ETN) and a background non steroidal anti inflammatory drug(NSAID).