Long-Term Adalimumab Provides Sustained Benefits in Axial Spondyloarthritis

Anti—tumor necrosis factor (anti-TNF) agents have proven efficacy in treating patients with axial spondyloarthritis, including those patients with nonradiographic axial spondyloarthritis (nrAxSpA). A recent study provides the final long-term efficacy and safety results from the phase 3 ABILITY-1 trial’s open-label extension in patients with nrAxSpA, which show that the anti-TNF agent adalimumab (Humira) provided sustained clinical and functional improvements through 3 years.

Patients included in the extension were 18 years or older, had nrAxSpA, and had not responded adequately to (or had a contraindication for) at least 1 non-steroidal anti-inflammatory drug. The ABILITY-1 trial randomized patients to receive subcutaneous injections of either 40 mg of adalimumab or placebo every other week for 12 weeks, and in the open-label extension, patients received 40 mg of adalimumab every other week for up to 3 years. Patients in the total efficacy population (n = 185) were divided into a population of those positive for magnetic resonance imaging (MRI)—detected inflammation and for elevated C-reactive protein (CRP) levels (n = 142) and those who tested negative for both (n = 43).

Clinical and MRI remission were defined, respectively, as an Ankylosing Spondylitis Disease Activity Score (ASDAS) of less than 1.3 and a Spondyloarthritis Research Consortium of Canada (SPARCC) MRI score of less than 2 for sacroiliac joints, spine, or both. Physical function was assessed using the Bath Ankylosing Spondylitis Functional Index (BASDAI).

The researchers found the following:

• At week 156, the mean ASDAS was 1.9 (standard deviation [SD], 1.2) and BASDAI was 3.3 (SD, 2.7) in the MRI/CRP-positive subgroup. Mean changes from baseline to week 156 were —1.4 (SD, 1.3) for ASDAS and –3.1 (SD, 2.6) for BASDAI.
• In the MRI/CRP-negative subgroup, the mean ASDAS was 1.8 (SD, 1.0) and BASDAI was 3.7 (SD, 2.6). Mean changes from baseline to week 156 were —1.1 (SD, 1.0) for ASDAS and –2.9 (SD, 2.7) for BASDAI.

• There was a reduction in SPARCC scores from baseline at 1 and 2 years in the MRI/CRP-positive group, as well as in the total efficacy population.
• Among the MRI/CRP-positive group, MRI remission in the location of positive MRI-identified inflammation was achieved by patients with an inflamed sacroiliac joint, spine, or both, in 71%, 52%, and 50% of patients, respectively, at year 2.
• In the MRI/CRP-positive group, 30% of patients achieved partial remission and 30% achieved inactive disease at year 3. In the MRI/CRP-negative group, 17% achieved partial remission and 24% achieved inactive disease.
• Sustained clinical remission was achieved by 34 patients (24%) at year 2, and 32 patients (23%) at year 3 in the MRI/CRP-positive group.
• Among patients with abnormal physical function at baseline, all patients who achieved sustained clinical remission also regained normal function.

During the study period, there were no incidents of malignancy, vasculitis, demyelinating disease, or reactivation of hepatitis B reported, though serious adverse events, including infections, were reported by 17.4% of patients in the overall safety population.

The authors conclude that adalimumab provided sustained clinical and functional improvements through 3 years, and also provided suppression of MRI axial inflammation in patients with nrAxSpA. These findings, say the authors, support the favorable benefit-risk profile of long-term adalimumab therapy in this patient population.

Reference

van der Heijde D, Sieper J, Maksymowych WP, et al. Clinical and MRI remission in patients with nonradiographic axial spondyloarthritis who received long-term open-label adalimumab treatment: 3-year results of the ABILITY-1 trial. Arthritis Res Ther. 2018;20(1):61. doi: 10.1186/s13075-018-1556-5.