Abbott announced results from the Phase 3 ABILITY-1 study of HUMIRA® (adalimumab) in patients with active non-radiographic axial spondyloarthritis (axSpA) at the American College of Rheumatology Annual Scientific Meeting (ACR) in Chicago.

HUMIRA (adalimumab) is a prescription medicine designed to reduce signs and symptoms of ankylosing spondylitis in adults. It can be used alone or with certain other medicines to reduce signs and symptoms of psoriatic arthritis in adults and could prevent further damage to bones and joints, assisting patients to perform their daily activities.

AxSpA is a debilitating condition that first presents itself as inflammatory low back pain. It can be accompanied by the presence of the HLA-B27 gene, arthritis, and inflammation in the eye and/or gastrointestinal tract. Researchers observed at week 12 that over twice as many study participants in the HUMIRA group achieved the primary endpoint of 40% improvement in the Assessment of SpondyloArthritis international Society criteria (ASAS 40) compared with those receiving placebo.

Spondyloarthritis (SpA), a group of diseases sharing common clinical, radiographic and genetic features includes ankylosing spondylitis (AS), reactive arthritis, psoriatic arthritis (PsA), enteropathic or inflammatory bowel disease (IBD)-related arthritis and undifferentiated SpA. SpA is categorized either as axial or peripheral depending on which part of the body is mainly affected.

According to ASASs proposal, the new classification criteria for axial and peripheral SpA validation includes the use of magnetic resonance imaging (MRI), in addition to traditional X-rays to visualize sacroiliitis, an inflammation of the sacroiliac joint which connects the lower spine and pelvis. Patients with non-radiographic axSpA display similar signs and symptoms compared with those suffering from AS, but their X-rays do not display evidence of structural damage in form of sacroiliitis. The ASAS criteria have been designed to enable health professionals to classify people with non-radiographic axSpA who may remain undiagnosed otherwise.

ABILITY-1 is an ongoing multi-country, Phase 3 study designed to evaluate the efficacy and safety of HUMIRA in axSpA patients without radiographic sacroiliitis and uses the ASAS 40 response criteria for the primary endpoint instead of the less stringent ASAS 20 response criteria. It is the first large pivotal study using ASAS criteria for classifying non-radiographic axial SpA patients and examines anti-tumor necrosis factor medication (anti-TNF) in treating patients with non-radiographic axSpA.

Researchers examined patients by using several disease activity measures, including the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). Although eligible patients fulfilled the ASAS axSpA criteria, they did not fulfill the modified New York criteria for the diagnosis of AS. All patients had a BASDAI score of ≥4 cm, a total back pain visual analogue scale (VAS) score of ≥40 mm and inadequate response/intolerance/contraindication for nonsteroidal anti-inflammatory drugs (NSAIDs).

For the study, researchers randomized 192 patients to be administered with 40mg of HUMIRA taken every other week or placebo for 12 weeks. This was followed by a 92-week open-label extension period where all patients are treated with HUMIRA. The ratio was 1:1 with similar baseline demographics and disease characteristics between the HUMIRA and placebo group. The primary endpoint was set as ASAS 40 response at week 12. Assessment of other efficacy endpoints included: ASAS 5/6, ASAS 20, ASAS partial remission, Ankylosing Spondylitis Disease Activity Score (ASDAS) inactive disease state, BASDAI 50, average change in C-reactive protein (CRP) and in Spondyloarthritis Research Consortium of Canada (SPARCC) sacroiliac joint and spine scores.

Professor Joachim Sieper, Head of Rheumatology at the University Hospital Charité, Berlin, Germany commented:

“There is a tremendous unmet need for effective treatments for patients with active non-radiographic axSpA who are normally of young age. Adalimumab has already been shown to be an effective treatment for two other spondyloarthritides: ankylosing spondylitis and psoriatic arthritis. The results of this study, applying for the first time the new ASAS criteria, are encouraging for its potential in treating another condition within this group of diseases.”

The study results demonstrated that a significantly higher percentage (36.3%) of patients in the HUMIRA group achieved the primary endpoint and other clinical and imaging outcomes compared with 14.9% in the placebo group. (P

HUMIRA is not approved for the treatment of spondyloarthritides other than ankylosing spondylitis and psoriatic arthritis.

Written by Petra Rattue