Inclusion Criteria:

- Age 18 or above

- PsA with active disease despite treatment with non-steroidal anti-inflammatory drug
(NSAID)

- 3 or more swollen and tender joints

- Inadequate response after 4 weeks of, or intolerance to nonsteroidal
anti-inflammatory drug therapy.

- Methotrexate (MTX) is allowed during the study only if it has been taken for at least
3 months previously, with the dosage stable for at least 4 weeks prior to the
baseline visit.

- Prednisone ≤ 10 mg/day and/or nonsteroidal anti-inflammatory drugs must have been
taken at stable dosage for at least 2 weeks before entering the trial.

- Informed consent

Exclusion Criteria:

- Little or no ability for self-care

- Used a DMARD other than methotrexate or received intra-articular, intramuscular, or
intravenous corticosteroids in the 4 weeks before screening.

- Topical vitamin A (Neotigason CR) or D analog preparations (Daivonex CR), and
anthralin for psoriasis within 2 weeks of baseline.

- Concurrent treatment with MTX at dosages > 15 mg/week and/or corticosteroids in a
prednisone-equivalent dosage of > 10 mg/day.

- Prior anti-TNF therapy at any time.

- Infected joint prosthesis during the previous 5 years.

- Serious infections, such as hepatitis, pneumonia, pyelonephritis in the previous 3
months.

- Any chronic infectious disease such as renal infection, chest infection with
bronchiectasis or sinusitis.

- Active tuberculosis requiring treatment within the previous 3 years.

- Opportunistic infections such as herpes zoster within the previous 2 months.

- Any evidence of active cytomegalovirus; active Pneumocystis carinii; or
drug-resistant atypical mycobacterial infection.

- Known hypersensitivity to murine proteins

- Current signs or symptoms of severe, progressive, or uncontrolled renal, hepatic,
haematological, gastrointestinal, endocrine, pulmonary, cardiac, neurological, or
cerebral disease.

- A history of lymphoproliferative disease including lymphoma or signs suggestive of
disease, such as lymphadenopathy of unusual size or location (ie, lymph nodes in the
posterior triangle of the neck, infraclavicular epitrochlear, or periaortic areas);
splenomegaly.

- Any known malignant disease except basal cell carcinoma currently or in the past 5
years.