Vinod Chandran, MBBS, MD, DM, PhD
Although most patients with psoriatic arthritis (PsA) have concomitant psoriasis, many with PsA who are enrolled in clinic trials as well as in rheumatology clinic do not have severe psoriasis. Therefore, an unanswered question is how much psoriasis symptoms contribute to impaired quality of life (QOL) in PsA patients. This question was addressed in a recent study by Taylor and colleagues. This post hoc analysis of two phase 3 studies, OPAL Broaden and OPAL Beyond, included 816 patients with active PsA and an inadequate response to previous therapies who received tofacitinib, adalimumab, or placebo. The analyses demonstrated that Itch Severity Item (ISI) scores of 7-10, Physician's Global Assessment of Psoriasis (PGA-PsO) scores of 4, and Patient's Global Joint and Skin Assessment-Visual Analog Scale (PGJS-VAS) scores of 90-100 mm corresponded with Dermatology Life Quality Index (DLQI) scores categorized as having a very large effect on a patient's life. An improvement of ≥ 3 points in ISI, ≥ 2 points in PGA-PsO, and ≥ 40 mm in PGJS-VAS translated to a clinically meaningful improvement in DLQI scores; improvements from baseline of ≥4/≥3/≥40-mm in the above scores, respectively, were also associated with clinically meaningful improvements across SF-36v2 (Short-Form Health Survey) domains. Thus, dermatologic symptoms are substantially associated with QOL in patients with active PsA, and improvements in skin measures could translate to clinically meaningful improvements in their QOL.
There is also increasing scrutiny on sex differences in PsA. Eder and colleagues conducted a post hoc analysis of two phase 3 trials that included 679 patients with active PsA who were either biologic-naive (SPIRIT-P1) or showed an inadequate response to one or two tumor necrosis factor inhibitors (TNFi) (SPIRIT-P2) and were randomly assigned to receive ixekizumab, an IL-17A inhibitor (IL-17Ai), or placebo. They demonstrated that at baseline female vs male patients had significantly higher Health Assessment Questionnaire Disability Index scores (P ≤ .003), with a significantly higher proportion of male vs female patients in the ixekizumab every-4-weeks treatment arm (53.8% vs 38.3%) and ixekizumab every-2-weeks treatment arm(41.2% vs 28.1%) achieving ≥50% and ≥70% improvement in the American College of Rheumatology response criteria, respectively (both P < .05). Thus, female patients with PsA exhibited significantly higher disease activity at baseline and a poorer response to ixekizumab.
Janus kinase (JAK) inhibitors have been shown to improve inflammatory and other types of pain in rheumatoid arthritis. To further evaluate the effect of inhibition of JAK1 on pain, McInnes and colleagues aimed to evaluate the effect of upadacitinib on pain outcomes in patients with active PsA or ankylosing spondylitis across three randomized trials (SELECT-PsA-1 and -2 for PsA; SELECT-AXIS 1 for ankylosing spondylitis). A significantly higher proportion of patients receiving 15 mg upadacitinib vs placebo achieved ≥30%, ≥50%, and ≥70% reductions in pain as early as 2 weeks (P < .05), with improvements sustained up to week 56. Further research on whether improvement in pain is at least partially independent of improvement in musculoskeletal inflammation is required.
Persistence of drug treatment is an important outcome and is a surrogate measure of safety and effectiveness. Vegas and colleagues assessed the long-term persistence of different biologic classes in a nationwide cohort study that included 16,892 adults with psoriasis and 6531 adults with PsA who initiated first-line treatment with a TNFi, IL-12/23 inhibitors (IL-12/23i), or an IL-17i. Treatment persistence was higher with IL-17i than with TNFi (weighted hazard ratio [HR] 0.70; P < .001) or IL-12/23i (weighted HR 0.69; P < .001); however, IL-12/23i and TNFi showed similar persistence (P = .70). Thus, IL-17i may be associated with higher treatment persistence in PsA compared with TNFi.