Clinical Edge Journal Scan Commentary: PsA February 2022

Vinod Chandran, MBBS, MD, DM, PhD

Identifying risk factors associated with transition from cutaneous psoriasis to arthritic psoriasis remains a hot area of research. In a retrospective nested case-control study using the resources of the Rochester Epidemiology Project, Karmacharya et al¹ identified 164 patients with incident PsA between 2000 and 2017. Among the 158 total patients satisfying study criteria, 64 (41%) had concurrent psoriasis and PsA and 94 (59%) had onset of psoriasis before PsA. The median time from psoriasis diagnosis to the incidence of PsA was 35.5 months with age at psoriasis onset (odds ratio [OR] per 10-year decrease 1.63; 95% CI 1.26-2.11) and its severity (OR for severe vs. mild 3.65; 95% CI 1.18-11.32) being associated with having a psoriasis diagnosis >1 year prior to incident PsA. Early onset as well as severe psoriasis is associated with the HLA- C*06 allele as is longer psoriasis-PsA latency. Although not evaluated in this study, this genetic factor, or other factors such as detection bias, may underly these observations.

Once diagnosed, stratification of PsA severity is important for planning treatment. Towards this goal, Dubash et al² demonstrated that the presence of dactylitis indicates a more severe PsA phenotype. In a study of 177 disease-modifying antirheumatic drug (DMARD)-naive patients with early PsA, they found that those with dactylitis (46%) had significantly higher tender and swollen joint counts and C-reactive protein than those with non-dactylitic PsA. Ultrasound synovitis and erosions were also significantly more prevalent in dactylitic PsA. Thus, the presence of dactylitis indicates a more severe phenotype, and patients with dactylitis should be treated aggressively to improve long-term outcomes.

Novel therapies are being frequently evaluated in PsA and a recent target is interleukin (IL)-23, a key cytokine in the T-helper 17 (Th17) pathway and in the pathogenesis of psoriatic disease. Risankizumab is a novel monoclonal antibody targeting IL-23. In the double-blind phase 3 KEEPsAKE 1 study including 964 patients with active PsA and inadequate response to one or more conventional synthetic (cs) DMARDs. They were randomly assigned to receive 150 mg risankizumab or placebo, Kristensen et al³ demonstrated that, at week 24, at least a 20% improvement in the American College of Rheumatology score (ACR20) was achieved by a significantly higher proportion of patients receiving risankizumab vs. placebo (57.3% vs. 33.5%; P < .001). Treatment-emergent adverse events were mild-to-moderate and reported at similar frequencies in the risankizumab (40.4%) and placebo (38.7%) groups. Thus, risankizumab was efficacious in reducing clinical manifestations of PsA in patients with inadequate response to csDMARDs with no new adverse events. An important question when treating patients with PsA with targeted therapies is the need for concomitant therapy with csDMARDs. In a pooled analysis of 2 phase 3 trials, SELECT-PsA 1 and SELECT-PsA 2, 1,916 patients with active PsA with an inadequate response to ≥1 non-biologic (nb) DMARDs or biologic DMARDs were randomly assigned to placebo, 15 mg upadacitinib, or 30 mg upadacitinib as monotherapy or in combination with ≤2 nbDMARDs for 24 weeks, Nash et al⁴ demonstrated that at week 12, ACR20 response was achieved by a similar proportion of patients receiving 15 mg upadacitinib or 30 mg upadacitinib as monotherapy (15 mg: 33.7%; 95% CI 24.4%-43.1%; 30 mg: 45.7%; 95% CI 36.9%-54.5%) or combination therapy (15 mg: 34.0%; 95% CI 27.9%-40.1%; 30 mg: 39.6%; 95% CI 33.7%-45.5%). Adverse events were generally similar between monotherapy and combination therapy. Although, we don’t have information regarding the sustainability of the response, these data indicate that upadacitinib may be used without concomitant csDMARDs in PsA.

References

1. Karmacharya P et al. Time to transition from psoriasis to psoriatic arthritis: A population-based study. Semin Arthritis Rheum. 2021(Dec 31):S0049-0172(21)00230-4.
2. Dubash S et al. Dactylitis is an indicator of a more severe phenotype independently associated with greater SJC, CRP, ultrasound synovitis and erosive damage in DMARD-naive early psoriatic arthritis. Ann Rheum Dis. 2021(Dec 10):annrheumdis-2021-220964.
3. Kristensen LE et al. Efficacy and safety of risankizumab for active psoriatic arthritis: 24-week results from the randomised, double-blind, phase 3 KEEPsAKE 1 trial. Ann Rheum Dis. 2022(Feb);81(2):225-231.
4. Nash P et al. Upadacitinib as monotherapy and in combination with non-biologic disease-modifying antirheumatic drugs for psoriatic arthritis. Rheumatology (Oxford). 2021(Dec 3):keab905.