Objective: To compare the abilities of three enthesitis indices to detect improvement in entheseal tenderness with the TNF antagonist golimumab in AS.
Methods: Adult patients with active AS were randomly assigned to receive s.c. injections of placebo or golimumab (50 or 100 mg) every 4 weeks. Patients with inadequate week 16 responses were switched (blinded) from placebo to golimumab 50 mg or from golimumab 50 mg to 100 mg. At week 24, all patients still receiving placebo crossed over to golimumab 50 mg. Enthesitis data through week 52 are reported herein. Enthesitis was measured by a trained, independent assessor who recorded the presence or absence of tenderness in 27 entheses, which allowed simultaneous determination of three different indices [12-point Berlin Index, 17-point University of California, San Francisco (UCSF) Index and 13-point Maastricht AS Enthesitis Score (MASES)].
Results: Three hundred and fifty-six AS patients were randomized to placebo (n = 78), golimumab 50 mg (n = 138) or golimumab 100 mg (n = 140); 355 had enthesitis data available for analysis. Using the UCSF Index, significant improvement from baseline vs placebo was observed for golimumab 100 mg at weeks 14 and 24. Using the MASES, significant improvement for golimumab 100 mg vs placebo at week 14 and a trend toward improvement at week 24 were observed. Using the Berlin Index, significant improvement for golimumab 100 mg vs placebo at week 14 was observed. Effect size determinations for changes to weeks 14, 24 and 52, respectively, in the Berlin (-0.27, -0.34, -0.42), UCSF (-0.44, -0.61, -0.55) and MASES (-0.30, -0.55, -0.39) indices suggested small to moderate effect sizes.
Conclusion: In patients with active AS, the UCSF Index appeared most sensitive in detecting the effect of golimumab 100 mg vs placebo on enthesitis.
Trial registration: clinicaltrials.gov, http://www.clinicaltrials.gov, NCT00265083.