Tofacitinib Successfully Improves Dactylitis in Psoriatic Arthritis

Treatment with tofacitinib, an oral Janus kinase (JAK) inhibitor, showed sustained improvement in dactylitis, and minimal occurrence of new dactylitis, in patients with psoriatic arthritis (PsA), according to a study published in BMC Rheumatology.¹

“Up to 50% of patients with PsA may experience dactylitis, and it is more common in feet than in hands,” investigators stated. “Dactylitic digits exhibit a greater degree of radiological damage than digits unaffected by dactylitis. As such, dactylitis is considered a core domain of musculoskeletal symptoms in PsA and is important for both patients and physicians when developing treatment strategies.”

The post-hoc analysis of 2 phase 3 studies, OPAL Broaden and OPAL Beyond, assessed patients with PsA treated with tofacitinib 5 mg or 10 mg twice daily (BID) or placebo. OPAL Broaden included patients with active PsA and inadequate response to conventional synthetic disease-modifying antirheumatic drugs (csDMARDs), while OPAL Beyond enrolled patients with active PsA and inadequate response to tumor necrosis factor inhibitors (TNFi).

Investigators evaluated changes in dactylitis by location and patient-reported outcomes (PROs). Primary endpoints included changes from baseline in the Psoriatic Arthritis Disease Activity Score (PASDAS), Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F), Mental Component Summary (MCS), physical functioning (PF), arthritis pain, Work Limitations Questionnaire (WLQI), and the Short- Form-36 Health Survey (SF-36). Dactylitis was evaluated via the Dactylitis Severity Score (DSS) as well as the proportions of patients with dactylitis. The Health Assessment Questionnaire-Disability Index (HAQ-DI) was used to determine PROs, which were evaluated by multivariate linear regression.

The analysis studied 710 patients, of which 373 (52.5%) had a baseline DSS > 0 and 337 (47.5%) reported no dactylitis at baseline (DSS = 0). Demographics and disease characteristics were similar among patient groups. At month 1, patients receiving tofacitinib 10 mg BID with DSS > 0 had greater improvements in DSS, regardless of location, when compared with placebo, with greater improvements reported in HAQ-DI score and HAQ-DI response rate at month 3 for patients receiving tofacitinib 10 mg BID when compared with the placebo cohort. Visual Analogue Scale (VAS) scores were also lower for those in the tofacitinib groups when compared with placebo and were maintained to month 6.

In patients with DSS > 0 receiving tofacitinib, ≤ 15% developed dactylitis in 1 or more digits at month 6. Only < 2% of those in the DSS = 0 group reported a new incidence of dactylitis at the 6-month mark. Additionally, PASDAS was lower in both tofacitinib cohorts when compared with placebo at month 1 and month 3, and results were maintained to month 6. The location of dactylitis was not linked to changes in PROs.

The low number of patients in the dactylitis groups and the short 6-month follow-up period limited the analysis. Inter- and intra-observer reliability was used to clinically assess dactylitis, which can be inconsistent. The degree of tenderness, used to grade the severity of dactylitis, was also impacted by inter-observer reliability. Lastly, investigators did not perform formal statistical testing to evaluate differences between treatment groups for dactylitis by location and changes in PROs.

“These results suggest that tofacitinib treatment may benefit those patients with PsA experiencing dactylitis, thus further supporting the use of tofacitinib as a treatment for PsA,” investigators concluded. “Further analyses of data collected over longer time periods are required to further assess the effects of tofacitinib on dactylitis in patients with PsA.”

Reference:

Orbai AM, Mease PJ, Helliwell PS, et al. Effect of tofacitinib on dactylitis and patient-reported outcomes in patients with active psoriatic arthritis: post-hoc analysis of phase III studies. BMC Rheumatol. 2022;6(1):68. Published 2022 Sep 1. doi:10.1186/s41927-022-00298-4