Vinod Chandran, MBBS, MD, DM, PhD
The effectiveness and safety of advanced therapies for psoriatic arthritis (PsA) was a focus of many published studies last month. Janus kinase inhibitors (JAKi) are a recent class of drugs made available to treat PsA and related diseases, and several clinical trials have been published. Sarabia and colleagues reported the results of a meta-analysis of 15 randomized controlled trials including 6757 patients with psoriasis or PsA who received treatment with a JAKi or placebo. Their analyses revealed that treatment with JAKi vs placebo was associated with higher odds of achieving American College of Rheumatology 20 (ACR20) response (odds ratio [OR] 4.45; 95% CI 3.64-5.44), with similar outcomes observed with tofacitinib vs placebo (OR 2.96; 95% CI 2.01-4.35) and non-tofacitinib JAKi vs placebo (OR 5.41; 95% CI 3.95-7.40). Serious adverse event rates were low (1%-7% in the maximum-dose intervention group).
Interleukin-23i (guselkumab, tildrakizumab, or risankizumab) are another class of biologics recently approved for the treatment of PsA. Preliminary results from a real-world study demonstrate the efficacy of these drugs for PsA. In a retrospective observational study including 80 patients with psoriasis (22 with PsA) who received guselkumab, tildrakizumab, or risankizumab, Elgaard and colleagues demonstrated that 40.9% or 36.4% of the PsA patients achieved complete or partial remission, respectively, compared with only 18.2% of patients with no improvement.
Regarding drug safety, a recent study demonstrated low rates of opportunistic infections with biologic disease-modifying antirheumatic drugs (bDMARD) and targeted synthetic DMARD (tsDMARD). Vassilopoulos and colleagues conducted a meta-analysis of 47 randomized controlled trials and 26 follow-up extension studies that included patients with PsA who received at least one dose of a bDMARD or a tsDMARD (n = 11,790) or placebo (n = 6425) during the placebo-controlled period, and 17,197 patients who received at least one dose of a bDMARD or a tsDMARD in the long-term extension period.
The cumulative incidence of opportunistic infections was < 3% when stratified by the mechanism of action: JAKi (2.72%; 95% CI 1.05%-5.04%), anti-interleukin (IL)-17i (1.18%; 95% CI 0.60%-1.90%), anti-IL-23i (0.24%; 95% CI 0.04%-0.54%), and TNFi (0.01%; 95% CI 0.00%-0.21%). These results are consistent with my own observations in my clinic. Thus, currently available advanced therapies, including JAKi and IL-23i, are effective and safe for the management of patients with PsA when used as monotherapy with or without conventional synthetic DMARD (csDMARD). Ongoing studies on combination therapy will provide us with guidance on the efficacy and safety of combining these drugs for the treatment of resistant disease.
Many patients do not respond to treatment, however. Actionable risk factors for lack of response are of clinical interest. One such factor is obesity. In an observational study of 774 adult PsA patients who started their first b/tsDMARD, Vallejo-Yague and colleagues reported that the odds of achieving minimal disease activity (adjusted OR [aOR] 0.45; 95% CI 0.24-0.82) and Disease Activity Index for Psoriatic Arthritis (DAPSA)-remission (aOR 0.42; 95% CI 0.21-0.85) were lower in the obese vs normal-weight group within the first year. Thus, obese patients had ~50% lower likelihood of achieving a state of low disease activity. Comprehensive management of PsA must include management of obesity and other comorbid conditions to achieve optimal outcomes.
Finally, an interesting study by Freuer and colleagues used bidirectional two-sample Mendelian randomization in 12,882 patients with inflammatory bowel disease (IBD), 21,770 matched controls, 5621 patients with psoriasis, 2063 patients with PsA, and 252,323 controls. The study found that genetically predicted IBD was associated with a higher risk for PsA (pooled OR 1.11; P = .003) with the risk being majorly mediated by Crohn's disease (OR 1.12; P = .002) and not ulcerative colitis (P = .70). Thus, patients with Crohn's disease need to be carefully evaluated for the development of PsA.