Successful short term treatment of patients with severe undifferentiated spondyloarthritis with the anti-tumor necrosis factor-alpha fusion receptor protein etanercept.

OBJECTIVE

Anti-tumor necrosis factor-a (TNF-alpha) therapy has been successfully used in patients with active ankylosing spondylitis (AS) and other subtypes of spondyloarthritis (SpA). Treatment options for patients with severe forms of undifferentiated spondyloarthritis (uSpA), a rather frequent SpA subset, are limited. In this open study we examined the efficacy of the TNF-alpha receptor fusion protein etanercept in patients with uSpA.

METHODS

Ten patients classified to have uSpA according to modified European Spondylarthropathy Study Group criteria in a severe and active stage of disease were included in the study and received etanercept in a dosage of 25 mg two times a week for 12 weeks, followed by an observation period of 12 weeks. The following outcome variables were used: Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Functional Index (BASFI), pain on a numerical rating scale, disability by the Funktionsfragebogen Hannover (FFbH), a validated questionnaire to assess functional disability, and quality of life (Medical Outcome Study Short Form-36, SF-36). The primary outcome variable was defined as >or= 50% improvement of the BASDAI.

RESULTS

Treatment with etanercept resulted in a >or= 50% regression of disease activity in 60% (95% CI 31-83%) of the patients. The mean BASDAI at baseline of 6.1 (range 3.7-9.2) dropped significantly to 3.5 at Week 12 (0.8-8.7; p = 0.01). Function, spinal pain, peripheral arthritis, enthesitis, quality of life, and acute phase reactants improved similarly. The FFbH improved from 62.8% to 69.7%. After cessation of anti-TNF therapy, 4 out of 8 patients relapsed after an average of 4.5 weeks (range 3-6). Two patients went into longstanding remission. No severe adverse events or major infections were observed.

CONCLUSION

This study strongly suggests that treatment with etanercept has short term efficacy in patients with active and severe uSpA. Since it is known that 30-50% of uSpA patients develop AS over time, it will be important to study whether this can be prevented by anti-TNF-alpha therapy.