Efficacy of infliximab in refractory ankylosing spondylitis:: results of a six-month open-label study

Objective. To evaluate the efficacy and safety of a loading regimen of the anti-tumour necrosis factor alpha (TNF-alpha) antibody infliximab in predominantly axial severe ankylosing spondylitis (AS). Methods. We enrolled in this study 50 patients (76% males, 87% HLA-B27(+), median age 35 yr, median disease duration 13 yr) with active AS [Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) greater than or equal to30/100 and serum C-reactive protein concentration greater than or equal to15 mg/l) despite treatment with a non-steroidal anti-inflammatory drug, and without peripheral arthritis, uveitis or active inflammatory bowel disease. Other disease-modifying anti-rheumatic drugs were discontinued greater than or equal to3 months before inclusion and were not allowed during the study. Patients received three infusions of infliximab (5 mg/kg) at weeks 0, 2 and 6 and were monitored clinically and biologically until week 24. Results. Forty-eight patients completed the treatment. In intention-to-treat analysis, all parameters were significantly improved at week 2 and generally reached maximal improvement at week 8. The proportion of responders, defined by a reduction of greater than or equal to20% in the global assessment of pain (GAP) or by the AS Assessment Study Group (ASAS 20%) criteria, and the proportion of patients reaching partial remission were 98, 94 and 70% respectively. Relapse, defined as greater than or equal to50% loss of maximal GAP improvement, occurred in 73% of completers, with a median delay of 14 weeks after the third infusion. No serious adverse event related to the treatment was observed. Conclusions. This study confirms, in a large group of severely affected AS patients, the remarkable efficacy of infliximab. Relapse usually occurred after discontinuation of the drug, but almost one-third of completers were still free of relapse 4 months after the last infusion.