Background Spondyloarthritis is associated with impaired physical function, health-related quality of life (HRQL), and work productivity. Adalimumab (ADA) is associated with improved clinical outcomes in patients with peripheral spondyloarthritis (pSpA).

Objectives To evaluate the effect of ADA treatment on physical function, HRQL and work productivity in patients with pSpA.

Methods ABILITY-2 is an ongoing multicenter, double-blind, randomized Phase III clinical trial of patients who fulfilled the Assessment of SpondyloArthritis international Society criteria for pSpA, did not have a diagnosis of psoriasis, psoriatic arthritis, or ankylosing spondylitis, and were biologic-naive. During the 12-week double-blind phase, patients were randomized 1:1 to receive ADA 40 mg every other week or placebo (PBO). Physical function was assessed using the disability index of the Health Assessment Questionnaire for SpA (HAQ-S), HRQL was assessed using the Short Form 36 Health Survey (SF-36) Physical Component Summary (PCS), and work productivity was assessed using the Work Productivity and Activity Impairment (WPAI) questionnaire. Changes in HAQ-S, SF-36 PCS, and work productivity at Week 12 were assessed using ANCOVA with adjustment for baseline scores. Changes in HAQ-S at Weeks 2, 4, 8, and 12 were further assessed using a linear mixed model with factors for treatment, week, and an interaction between treatment and week.

Results A total of 165 patients were enrolled (84 received ADA, 81 received PBO). The mean age was 40 years, 45% were men, and the duration of SpA symptoms averaged approximately 7 years. Mean baseline HAQ-S scores indicated moderate impairment. For both groups, mean baseline SF-36 PCS scores were lower than the general US population average of 49.1 (34.5 for ADA, 34.6 for PBO). Baseline WPAI scores indicated substantial work impairment in terms of absenteeism (13.5% average reduction for ADA, 11.2% for PBO) and activity impairment (55.8% average reduction for ADA, 54.6% for PBO). There was marginally better improvement in HAQ-S for the ADA group compared with PBO at Week 12 (-0.3 vs. -0.2, P=.051). Accounting for additional data and an interaction effect between treatment and study week in a mixed linear model, the ADA group showed improvement in mean HAQ-S scores that increased over time and that was significantly larger than PBO at Week 12 (-0.3 vs. -0.2, P=.047). ADA was also associated with significantly greater improvements in SF-36 PCS score (6.7 vs. 2.4, P<.001), absenteeism (-4.4 vs. 1.5, P=.047) and activity impairment (-19.5 vs. -8.5, P=.003) compared with PBO at Week 12.

Conclusions In this first pivotal trial of ADA in patients with pSpA, patients had substantial impairment of physical function, HRQL and work productivity at baseline. After 12 weeks of therapy, the ADA group had significantly larger improvements in physical function, HRQL, and work productivity compared to the PBO group.

Acknowledgements The authors would like to thank Eric Bertelsen and Cathryn M. Carter of Arbor Communications who provided medical writing and editing services in the development of this abstract. The financial support for these services was provided by AbbVie.

Disclosure of Interest P. Mease Grant/research support from: AbbVie. Amgen, BMS, Celgene, Genentech, Janssen, Lilly, Merck, Novartis, Pfizer, UCB, Consultant for: AbbVie. Amgen, BMS, Celgene, Genentech, Janssen, Lilly, Merck, Novartis, Pfizer, UCB, Speakers bureau: AbbVie. Amgen, BMS, Celgene, Genentech, Janssen, Lilly, Merck, Novartis, Pfizer, UCB, S. Rao Shareholder of: AbbVie, Employee of: AbbVie. The design, study conduct, and financial support for the study/trial was provided by AbbVie. AbbVie participated in the interpretation of data, review, and approval of the abstract., K. Betts Employee of: Analysis Group, under contract with AbbVie, M. Lu Employee of: Analysis Group, under contract with AbbVie, L. Fan Employee of: Analysis Group, under contract with AbbVie, A. Pangan Shareholder of: AbbVie, Employee of: AbbVie. The design, study conduct, and financial support for the study/trial was provided by AbbVie. AbbVie participated in the interpretation of data, review, and approval of the abstract., D. van der Heijde Grant/research support from: AbbVie, Amgen, AstraZeneca, BMS, Centocor, Chugai, Daiichi, Eli Lilly, GSK, Janssen Biologics, Merck, Novartis, Novo-Nordisk, Otsuka, Pfizer, Roche, Sanofi-Aventis, Schering-Plough, UCB, Vertex, Consultant for: AbbVie, Amgen, AstraZeneca, BMS, Centocor, Chugai, Daiichi, Eli Lilly, GSK, Janssen Biologics, Merck, Novartis, Novo-Nordisk, Otsuka, Pfizer, Roche, Sanofi-Aventis, Schering-Plough, UCB, Vertex, Employee of: Director of Imaging Rheumatology bv, M. Cifaldi Shareholder of: AbbVie, Employee of: AbbVie. The design, study conduct, and financial support for the study/trial was provided by AbbVie. AbbVie participated in the interpretation of data, review, and approval of the abstract.