Background Biological DMARDs targeting TNF-α, IL-17, and IL-12/23 (p40) are available. The high efficacy of these drugs has been proven in numerous clinical trials. However, there are some cases in which a change from one bDMARDs to another one is necessary because of the refractory nature of the disease, and there is no established method to select the optimal bDMARDs according to the individual case, despite the fact that various drugs are available.

Objectives We sought to investigate the selection of specific biological DMARDs based on characteristic lymphocyte phenotypes for treating PsA.

Methods we performed this study to evaluate the efficacy of biologics therapy in 64 patients with PsA after 6 months of therapy, and to compare the results of peripheral lymphocyte phenotyping using 8-colour flow cytometry, with specific focus on helper T cell subsets, between 26 patients with PsA and healthy donors. In addition, the therapeutic response of 26 patients in whom the optimal bDMARDs was strategically chosen based on the results of peripheral lymphocyte analysis was evaluated at 6 months of treatment intervention in comparison with 38 patients in whom the standard biological product was used based on the 2011 and 2015 EULAR recommendations. Thus, the possibility of the optimisation of drug selection for bDMARDs therapy based on peripheral blood lymphocyte phenotyping was investigated.

Results The 26 patients with PsA in the strategic treatment group were classified into the following 4 types based on the peripheral blood analysis: a CXCR3⁺CCR6^-CD38⁺HLA-DR⁺ activated Th1 cell-predominant type, CXCR3^-CCR6⁺ CD38⁺HLA-DR⁺ activated Th17 cell-predominant type, Th1/Th17-high type, and Th1/Th17-low type. Accordingly, ustekinumab was administered to the activated Th1 cell-predominant patients, secukinumab to the activated Th17 cell-predominant patients, secukinumab or TNF inhibitor to the Th1/Th17-high patients, and TNF inhibitor to the Th1/Th17-low patients. At 6 months of strategic treatment, there was a significant decrease in SDAI (from 16.2 to 3.52), DAS28 (ESR) (from 4.13 to 2.27), and PASI (from 8.36 to 2.40). There were no statistically significant differences in background factors at baseline between these 2 groups. Moreover, the proportion of patients with the combined use of MTX was significantly lower in the strategic bDMARDs treatment group. There were significant decreases in TJC, SJC, PGA, CRP, ESR, DAS28 (ESR), SDAI, and PASI in both groups at 6 months of therapy. There were no significant differences in the amounts of these decreases between the two groups. However, at 6 months of therapy, the rate of low disease activity achievement according to SDAI, DAS28 (ESR), and ACR20 response rate was significantly higher in the strategic bDMARDs treatment group.

Conclusions Strategic treatment in which different bDMARDs were selected according to phenotypic differences in helper T cells showed significantly higher efficacy than standard bDMARD therapy. The results of this study provide an important guide to the implementation of more effective therapeutic intervention.

Disclosure of Interest None declared