16.0040 Ankylosing Spondylitis Study

Inclusion Criteria: - Subjects completing 24 weeks of study drug in protocol 16.0037 qualify to enroll into this study Other patients to meet the following criteria: * Negative pregnancy test * Subjects agree to use appropriate contraception throughout study * Should be able to self-inject study drug or have someone who can do so * Capable of understanding protocol and willing to provide written informed consent Exclusion Criteria: * Any change in NSAID or prednisone dose within 2 weeks of baseline * Any change in hydroxychloroquine, sulfasalazine, or MTX dose within 4 weeks of baseline * Use of DMARDs other than those mentioned above, within 4 weeks of enrollment * Previous receipt of ani-TNF agents, other than etanercept * Receipt of any other investigational drug within 30 days of baseline * Grade 3 or 4 adverse event attributed to etanercept which recurred when etanercept was resumed * Abnormality in chemistry or hematology profiles or significant concurrent medical events.