Background/Purpose: To evaluate long-term effects of adalimumab (ADA) treatment on patient reported outcomes (PROs) in nonradiographic axial spondyloarthritis (nr-axSpA).

Methods: Ability-1 is an ongoing Phase III, multicenter, randomized, controlled trial of ADA vs. placebo (PBO) in patients with nr-axSpA (fulfilling ASAS axial SpA criteria but not modified New York criteria for AS). Following the 12-wk double-blind phase, all patients were switched to open-label (OL) ADA (represented by ADA/ADA and PBO/ADA groups) for 144 wks. This post hoc analysis evaluated physical function, health-related quality of life (HRQOL), and work productivity until Wk 52. Physical function was assessed using the disability index of the Health Assessment Questionnaire for Spondyloarthropathies (HAQ-S) and HRQOL using the Short Form 36 Health Survey (SF-36) Physical Component Summary (PCS) score. Productivity was assessed using the overall work impairment domain of the Work Productivity and Activity Impairment Questionnaire. Changes from baseline to Wk 12 were compared between groups using ANCOVA with adjustment for baseline scores and with treatment as a factor. Analyses were conducted on the intent-to-treat (ITT) population excluding 7 subjects from a noncompliant site and the OL population (patients who had at least 1 dose of OL ADA).

Results: After 12 wks of therapy in the double-blind period, the ADA group experienced statistically significant improvements in HAQ-S (p<0.02) and SF-36 PCS (p<0.001) compared with PBO. A total of 179 patients entered the OL period (87/91 and 92/94 from the original ADA and PBO arms, respectively) and 150/151/81 patients completed the HAQ-S, SF-36 PCS, and work productivity questionnaires, respectively, at Wk 52 (table). At Wk 52, approximately 62% of the patients met the minimum important difference (MID) for HAQ-S of 0.26 and 77% met the MID for SF-36 PCS of 3.0. Nearly 65% of the patients also met the MID for work productivity of 7% at Wk 52. PBO patients who switched to OL ADA experienced improvements in HRQOL and work productivity levels comparable to patients who received ADA through Wk 52. By Wk 52, patients in both groups achieved SF-36 scores (42.8 and 44.1 for the PBO/ADA and ADA/ADA groups, respectively) that approached the US general population norm of 50.

Conclusion: Patients who remained on ADA therapy for 52 wks had sustained improvement in PRO and productivity. Likewise, patients who received PBO and switched to ADA in the OL period showed improvement in physical function, HRQOL, and work productivity that was maintained through Wk 52.