 8. Subjects must screen negative for active tuberculosis TB by either a PPD or a QuantiFERON Gold test unless previously performed and documented within 3 months prior to screening. If patient tests positive for latent TB at screening, the chest X-ray at Screening must be negative for active TB and the patient must be started on or have completed an adequate course of therapy for latent tuberculosis at the Baseline visit. Patient must complete the entire 9 month course of treatment for latent TB. 