Therapeutic Effects of Apremilast on Enthesitis and Dactylitis in Real Clinical Setting: An Italian Multicenter Study

Introduction: Enthesitis and dactylitis are difficult-to-treat features of psoriatic arthritis (PsA), leading to disability and affecting quality of life. Objective: The aim of this study is to evaluate enthesitis (using the Leed enthesitis index (LEI)) and dactylitis at 6 and 12 months in patients treated with apremilast. Methods: Patients affected by PsA from fifteen Italian rheumatological referral centers were screened. The inclusion criteria were: (a) enthesitis or dactylitisphenotype; (b) treatment with apremilast 30 mg bid. Clinical and treatment history, including PsA disease activity, were recorded. Mann–Whitney and chi-squared tests were used to assess the differences between independent groups, and Wilcoxon matched pairs signed-rank test assessed the differences between dependent samples. A p-value of <0.05 was considered statistically significant. Results: The Eph cohort consisted of 118 patients (median LEI 3); the Dph cohort included 96 patients with a median dactylitis of 1 (IQR 1–2). According to an intention to treat analysis, 25% and 34% of patients with enthesitis achieved remission (i.e., LEI = 0) in T1 and T2. The remission of dactylitis was 47% in T1 and 44% in T2. The per protocol analysis (patients observed for at least 12 months) showed that both dactylitis and LEI significantly improved in T1 (median LEI 1 (IQR 1–3)) and T2 (median LEI 0 (IQR 1–2)). Conclusion: Eph and Dph PsA patients treated with apremilast experienced a significant improvement in enthesitis and dactylitis activity. After 1 year, enthesitis and dactylitis remission was achieved in more than one-third of patients.