The primary objective of this study was to determine the long-term safety of etanercept in adults with AS who had completed study 0881A3-311-EU.

This was an open-label, multicenter extension study that was conducted to evaluate the safety and efficacy of etanercept in the treatment of adult subjects with AS who had completed study 0881A3-311-EU. The study consisted of an open-label treatment period of up to approximately 96 weeks.

1. Completed the entire 12 weeks of therapy in study 0881A3-311-EU, or completed at least 8 weeks of therapy and returned for the week 12 visit in study 0881A3-311-EU.
2. Negative serum β-HCG pregnancy test at baseline (all women of childbearing potential).
3. Sexually active women of childbearing potential had to use a medically acceptable form of contraception. Medically acceptable forms of contraception included oral contraceptives, injectable or implantable methods, intrauterine devices, or properly used barrier contraception. Additionally, the use of condoms was suggested as an adjunct to the methods previously addressed to protect against sexually transmitted diseases and to provide additional protection against accidental pregnancy.
4. Sexually active men had to agree to use a medically accepted form of contraception during the study.
5. Able to reconstitute and self-inject test article or have a designee who can do so.
6. Capable of understanding and willing to provide signed and dated written voluntary informed consent before any protocol-specific procedures were performed.
7. Able to store injectable test article at 2°C to 8°C.