Enrolled subjects will be given either etanercept or placebo. A placebo looks just like the study drug but contains no active medication. Placebos help study doctors find out if the effects of the study drug are due to the drug itself or just because of being in the study. This type of study design helps measure the true effectiveness of a treatment. Patients have 2 chances in 3 of receiving etanercept and 1 chance in 3 of receiving placebo.