The aim of the study was to evaluate the efficacy of infliximab (IFX) treatment, 5 mg/kg every 6 weeks, in patients with active ankylosing spondylitis (AS) and to determine whether IFX dose reduction and interval extension, 3 mg/kg every 8 weeks during the second year sustained the treatment effect. The study was started in 2003 an finished in 2008.

Inclusion Criteria:

The patients had to fulfill the following four inclusion criteria:

(I) Age between 18 and 60 years, (II) proven diagnosis according to the modified New York criteria 12 for definitive AS, (III) active disease with Bath AS Disease Activity Index (BASDAI) score above 4 and (IV) current or previous treatment with conventional non-steroidal anti-inflammatory drugs (NSAID) in adequate doses without sufficient effect.

Exclusion Criteria:

• current signs or symptoms of severe, progressive or uncontrolled hepatic, hematological, pulmonary, cardiac, neurological or cerebral disease;
• ongoing or past serious infection (including HIV and past or current tuberculosis);
• pregnancy or breast feeding;
• current malignancy or history of malignancy within the past five years;
• congestive heart failure and any contraindication to MRI.

Patients with active ankylosing spondylitis with BASDAI>4