Objective. To evaluate the efficacy and safety of
adalimumab in patients with active nonpsoriatic peripheral
spondyloarthritis (SpA).
Methods. ABILITY-2 is an ongoing phase III,
multicenter study of adalimumab treatment. Eligible
patients age >18 years fulfilled the Assessment of
SpondyloArthritis international Society (ASAS) classification
criteria for peripheral SpA, did not have a prior
diagnosis of psoriasis, psoriatic arthritis (PsA), or
ankylosing spondylitis (AS), and had an inadequate
response or intolerance to nonsteroidal antiinflammatory
drugs (NSAIDs). Patients were randomized 1:1 to
receive adalimumab 40 mg every other week or matching
placebo for 12 weeks, followed by a 144-week open-label
period. The primary end point was the proportion of patients
achieving 40% improvement in disease activity
according to the Peripheral SpA Response Criteria
(PSpARC40) at week 12. This was defined as >40% improvement
from baseline (>20-mm absolute improvement
on a visual analog scale) in patient’s global
assessments of disease activity and pain, and >40%
improvement in at least one of the following features:
swollen joint and tender joint counts, total enthesitis
count, or dactylitis count. Adverse events were recorded
throughout the study.
Results. In total, 165 patients were randomized to
a treatment group, of whom 81 were randomized to
receive placebo and 84 to receive adalimumab. Baseline
demographics and disease characteristics were generally
similar between the 2 groups. At week 12, a greater
proportion of patients receiving adalimumab achieved a
PSpARC40 response compared to patients receiving
placebo (39% versus 20%; P 0.006). Overall, improvement
in other outcomes was greater in the adalimumab
group compared to the placebo group. The rates of
adverse events were similar in both treatment groups.
Conclusion. Treatment with adalimumab ameliorated
the signs and symptoms of disease and improved
physical function in patients with active nonpsoriatic
peripheral SpA who exhibited an inadequate response
or intolerance to NSAIDs, with a safety profile consistent
with that observed in patients with AS, PsA, or
other immune-mediated diseases.