Background Adalimumab (ADA) is indicated for the treatment of psoriatic arthritis (PsA) and ankylosing spondylitis (AS). Peripheral arthritis, enthesitis, and dactylitis are important features in patients (pts) suffering from spondyloarthritis (SpA). Pts with peripheral SpA not diagnosed with PsA or AS (non-PsA, non-AS) may also benefit from anti-TNF therapy. ABILITY 2 is the first randomized controlled trial to use the ASAS peripheral SpA criteria.¹

Objectives To evaluate efficacy and safety of ADA in pts with non-PsA, non-AS peripheral SpA.

Methods ABILITY 2 is an ongoing, multicenter phase 3 study. Eligible pts were age ≥18 yrs, fulfilled ASAS peripheral SpA criteria, did not have a diagnosis of psoriasis, PsA, or AS, and had inadequate response to NSAIDs. Pts were randomized 1:1 to ADA 40 mg every other wk or placebo (PBO) for 12 wks followed by a 92-wk open-label extension. Primary endpoint was the proportion of pts achieving peripheral SpA response criteria (PSpARC 40) at wk 12: ≥40% improvement (≥20 mm absolute improvement) from baseline (BL) in Patient Global Assessment of Disease Activity (PGA) and PGA-pain and ≥40% improvement in ≥1 of the following: SJC and TJC; Enthesitis Count, or Dactylitis Count. Other outcomes included Physician Global Assessment (PhGA), BASDAI, enthesitis indices, HAQ-S, and SF-36v2. Adverse events (AE) were collected throughout the study.

Results 165 pts were randomized, 84/81, ADA/PBO. BL demographics/disease characteristics were similar between groups, except mean age was higher (43/39 yrs) and % pts with dactylitis count>0 was lower (16/30) in the ADA group. At BL, 99% of pts had TJC>0, 93% had SJC>0, and 87% had enthesitis count>0. At Wk 12, the proportion of ADA pts achieving PSpARC 40 was higher vs. PBO (P=.006) (table). Overall, mean improvement in other outcomes was greater with ADA vs. PBO. AE incidence rates were similar [ADA/PBO (%)]: any AEs (54.8/54.3), serious AEs (1.2/1.2), and infectious AEs (21.4/28.4); there were no serious infections, TB, or malignancies.

Conclusions Adalimumab significantly improved signs, symptoms, and physical function of pts with active non-PsA, non-AS peripheral SpA and was well-tolerated. ABILITY 2 results suggest that ADA can be a treatment option for peripheral SpA pts with inadequate response to NSAIDs.

1. Rudwaleit M, et al. Ann Rheum Dis 2011;70:25-31.

Disclosure of Interest P. Mease Grant/Research support from: Abbott, Consultant for: Abbott, Speakers Bureau: Abbott, J. Sieper Grant/Research support from: Abbott, Merck, Pfizer, UCB, Consultant for: Abbott, Merck, Pfizer, UCB, Speakers Bureau: Abbott, Merck, Pfizer, UCB, F. Van den Bosch Grant/Research support from: Abbott, Merck, UCB, Speakers Bureau: Abbott, Merck, P. Rahman Grant/Research support from: Janssen, Schering, Consultant for: Abbott, Amgen, Janssen, Roche, Schering, Speakers Bureau: Abbott, Amgen, Janssen, Schering, BMS, K. Obermeyer Shareholder of: Abbott, Employee of: Abbott, A. Pangan Shareholder of: Abbott, Employee of: Abbott