medwireNews: Measuring interleukin (IL)-22 levels may help predict whether IL-17 inhibitors or tumor necrosis factor (TNF) inhibitors are more suitable for patients with psoriatic arthritis (PsA), Japanese research suggests.
Yoshiya Tanaka and colleagues, from the University of Occupational and Environmental Health in Kitakyushu, initially reviewed baseline serum cytokine levels in 47 patients who had received at least 1 year of treatment with either an IL-17 inhibitor (n=23) or a TNF inhibitor (n=24).
The analysis identified serum IL-22 levels as a predictor of DAPSA remission at 1 year in the patients who had received IL-17 inhibitor therapy. Specifically, individuals who achieved DAPSA remission had significantly lower baseline IL-22 levels than those who did not, at a median of 0.50 versus 1.08 pg/mL.
Conversely, none of the seven cytokines assessed predicted DAPSA remission at 1 year after TNF inhibitor therapy, and none predicted achievement of PASI90 response or minimal disease activity in either treatment group.
The researchers then used area under the receiver operating characteristic curve analysis to establish that the optimal cutoff for classifying patients as having high or low IL-22 concentrations was 0.61376 pg/mL.
They found that individuals with low IL-22 levels were “characterized by a preferential increase in serum levels of IL-17” whereas those with high IL-22 levels had increased TNF-α. This led to a proposed strategy of using IL-17 inhibitors to treat patients with low IL-22 levels and TNF inhibitors for those with high IL-22 levels.
Tanaka et al validated their strategy using data from a cohort of 34 patients who had been prescribed an IL-17 inhibitor or a TNF inhibitor on the basis of shared decision-making.
They identified 17 patients that had received strategic treatment, ie, an IL-17 inhibitor if they had low IL-22 and a TNF inhibitor if they had high IL-22, and a further 17 patients who received mismatched treatment (n=17).
The researchers report in Arthritis Research & Therapy that the proportion of patients who achieved minimal disease activity at 6 months was significantly higher in the strategic treatment group than in the mismatched treatment group, at 70.6% versus 25.3%.
In addition, the rates of minimal disease activity (82.3 vs 41.2%) and DAPSA remission (58.8 vs 25.3%) at 12 months were significantly higher with strategic versus mismatched treatment.
Conversely, there were no significant differences between the two groups in the proportions achieving a PASI75 or PASI90 response at either 6 or 12 months.
Tanaka and co-authors conclude that their study “is the first to demonstrate the possibility of optimizing the selection between TNF [inhibitors] and IL-17 [inhibitors] based on serum IL-22 concentrations.”
However, they add: “Further large-scale studies in independent, prospectively collected datasets are required to verify that IL-22 is indeed a biomarker of treatment response in these patients.”
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