Greater BASDAI, ASDAS Responses With Upadacitinib in PsA With Axial Involvement

Compared with placebo, treatment with upadacitinib was found to result in greater responses to Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Ankylosing Spondylitis Disease Activity Score (ASDAS) among patients with psoriatic arthritis (PsA) with axial involvement, according to study results published in Arthritis Research & Therapy.

Researchers conducted a post hoc analysis to evaluate the efficacy and safety of upadacitinib for patients with active PsA and axial involvement, based on the SELECT-PsA 1 and SELECT-PsA 2 phase 3 trials (ClinicalTrials.gov Identifiers: NCT03104400 and NCT03104374, respectively).

Eligible participants included adults aged 18 years and older with an active PsA diagnosis with an inadequate response to nonbiologic disease-modifying antirheumatic drugs (non-bDMARD) or bDMARDs.

Patients were randomly assigned to receive once-daily oral upadacitinib 15 mg, upadacitinib 30 mg, placebo, or subcutaneous adalimumab 40 mg every other week (SELECT-PsA 1 only). At week 24, patients who initially received placebo were administered upadacitinib 15 mg or 30 mg.

Researchers measured the effectiveness of treatment among patients with PsA with axial involvement at weeks 12, 24, and 56. Effectiveness was measured using BASDAI and ASDAS scores.

Researchers also recorded any new treatment-emergent adverse events that occurred up to week 56.

In the SELECT PsA 1 trial, 396 of 1281 (30.9%) patients with PsA were identified as having axial involvement, based on investigator judgment. In the SELECT PsA 2 trial, 151 of 423 (35.7%) patients were identified as having axial involvement, based on investigator judgment. With the inclusion of both investigator- and patient-reported outcome (PRO)-based criteria, the percentage of patients with axial involvement was 22.6% in the SELECT-PsA 1 trial and 28.6% in the SELECT-PsA 2 trial.

Both studies showed that upadacitinib 15 mg vs placebo led to greater improvements in overall BASDAI scores at weeks 12 and 24, regardless of the criteria used to define axial involvement. In patients with PsA with axial involvement, defined by investigator judgment, upadacitinib vs adalimumab led to greater score improvements at week 24.

Both studies indicated that more patients achieved at least a 50% improvement from baseline in BASDAI (BASDAI50) with upadacitinib 15 mg compared with placebo at weeks 12 and 24, regardless of the definition of axial involvement. At week 24, upadacitinib 15 mg vs adalimumab resulted in improvements, based on investigator judgment.

At 12 weeks, there was no significant difference in clinical response between upadacitinib 15 mg and adalimumab for BASDAI, modified BASDAI, and BASDAI50. However, at 24 weeks, the clinical response was slightly higher for upadacitinib than adalimumab. Furthermore, both studies showed that upadacitinib continued to provide clinical improvements, according to the BASDAI and ASDAS efficacy measures, at week 56.

The study was limited by the reliance on patients’ recollection of information regarding delays in the diagnosis and treatment process.

The study authors concluded, “[T]hese data provide important information for treating clinicians on the efficacy and safety of upadacitinib 15 mg in axial disease and may help guide treatment decisions for [patients with] PsA with axial involvement.”