Vinod Chandran, MBBS, MD, DM, PhD
To address this gap in knowledge, Möller and colleagues compared the effectiveness of the first bDMARD in patients with PsA with low vs high joint counts (LJC and HJC, respectively). Using the Swiss Clinical Quality Management registry for rheumatic diseases, they obtained data on 387 patients with PsA who had either LJC (n = 197) or HJC (n = 190) and received bDMARD. As expected, patients with HJC had a higher burden of disease. Despite the higher burden, patients in both groups showed similar treatment efficacy in terms of drug retention. Consistent with previous reports, female sex was associated with lower treatment persistence, whereas concomitant treatment with conventional synthetic DMARD (csDMARD) was associated with longer bDMARD persistence. Thus, baseline joint counts may not be a good criterion for choosing who should be treated with bDMARD. The presence of active disease and lack of response to prior csDMARD is sufficient.
Persistence with therapy is an important indicator of drug effectiveness in the real world. A recent report from the CorEvitas registry by Mease and colleagues demonstrated that nearly 80% of patients with PsA persisted with guselkumab (an interleukin [IL]–23 inhibitor) treatment for 6 months and showed improvements in peripheral joint and skin symptoms. This study evaluated 114 patients with active PsA, > 90% of whom were previously treated with b- and tsDMARD. The mean scores for clinical Disease Activity Index in PsA, overall joint and skin activity, patient-reported pain, and body surface area with psoriasis improved significantly.
Choosing the next therapy after lack of success with treatment with a tumour necrosis factor (TNF) inhibitor and an IL-17A inhibitor is difficult. One question is whether one should try another IL-17A inhibitor or move to another class of therapy. Hansen and colleagues tried to address this question by analyses of data from the Danish Rheumatology Registry. Patients with PsA who underwent prior treatment with one or more TNF inhibitor and switched to either first-line (n = 534) or second-line (n = 102) IL-17A inhibitors (ixekizumab or secukinumab) were included. Similar persistence with therapy was observed between first-line and second-line IL-17A inhibitor switchers and between second-line secukinumab and second-line ixekizumab switchers. Withdrawal reasons were similar for both first-line and second-line switchers when considering adverse events; however, withdrawal due to lack of successful therapy was higher for the first-line vs second-line switchers (34% vs 18%). An important piece of information missing in the report was whether the lack of successful treatment with first-line therapy with an IL-17A inhibitor was primary (no response at all) or secondary (initial response and later failure). One presumes that patients with primary failures are less likely to respond to another IL-17A inhibitor compared with patients with secondary failures. Nevertheless, this large population-based study suggests that the failure of first-line IL-17A inhibitor therapy should not deter treatment with second-line IL-17A inhibitors.
Finally, Schett and colleagues looked at serum cytokine changes after treatment with guselkumab in patients with PsA with inadequate response to TNF inhibitor (TNFI-IR). Using clinical data and biosamples from patients enrolled in the COSMOS study, which included patients with active PsA and TNFI-IR who were randomly assigned to receive either guselkumab (n = 189) or placebo (n = 96), they showed that the serum levels of IL-17A, IL-17F, IL-22, and serum amyloid A were reduced significantly by week 4 and were sustained through week 48 in the guselkumab group vs the placebo group. Patients who achieved a clinical response to guselkumab at week 24 showed higher baseline IL-22 and interferon- γ levels as well as a significant reduction in IL-6 levels at week 4 compared with nonresponders. These markers are candidates for predictors for response to guselkumab in this population.