Effect of apremilast on whole-body magnetic resonance imaging of peripheral and axial inflammation in patients with psoriatic arthritis

Objectives: To describe the effect of apremilast on peripheral and axial psoriatic arthritis (PsA) manifestations as assessed by whole-body magnetic resonance imaging (WB-MRI), including the effect of apremilast on inflammation in all peripheral joints and entheses, spine and sacroiliac joints, hip and knee joints, and heel entheses. Methods: MOSAIC was a phase 4, multicentre, single-arm, open-label study of apremilast 30 mg twice daily ± concomitant stable methotrexate for 48 weeks in patients with PsA (NCT03783026). MRI of the clinically most affected hand and whole body was performed at baseline, 24 weeks, and 48 weeks. Here, we report secondary and post hoc outcomes of changes from baseline to weeks 24 and 48 in axial or peripheral inflammation, based on WB-MRI assessment. Results: Overall, 123 patients were enrolled across 29 global locations and 122 were treated with apremilast and included in this analysis. At weeks 24 and 48, respectively, statistically significant decreases were observed from baseline in least squares mean (95% CI) for total (peripheral + axial) inflammation (−3.6 [−6.3, −0.9] and −3.9 [−7.1, −0.6]), total peripheral inflammation (−3.5 [−5.5, −1.5] and −4.1 [−6.4, −1.7]), peripheral joint inflammation (by Whole-Body Scoring System for Inflammation in Peripheral Joints and Entheses in Inflammatory Arthritis method; −3.4 [−5.1, −1.7] and −3.6 [−5.7, −1.5]), and inflammatory lesions of the spine (by Canada-Denmark method; −2.6 [−3.6, −1.5] and −2.1 [−3.7, −0.6]). Post hoc analyses showed that decreases in MRI inflammation were more prominent in patients with moderate vs high baseline disease activity. Conclusions: Apremilast reduced both peripheral and axial inflammation in patients with PsA.