The TNF/IL-23/IL-17 axis-Head-to-head trials comparing different biologics in psoriasis treatment

Psoriasis is a T cell-mediated disease with autoimmune characteristics modulated by genetic susceptibility along with environmental triggers. Inflammatory pathways marked with excessive production of cytokines IL-12 and IL-23, drive differentiation of pathogenic T cell responses resulting in TNF and IL-17 production. These cytokines are an integral part of the TNF/IL-23/IL-17 axis, which is responsible for maintaining inflammation in psoriatic skin. Our improved understanding of the immunopathogenesis led to the development of biological drugs in the treatment of moderate-to-severe disease. Biologics have revolutionized the management of psoriasis, highlighting the central role of TNF/IL-23/IL-17 axis in the physiopathology of the disease. Still, psoriasis usually requires long-term treatment, aiming to fully remove psoriatic lesions without experiencing adverse events. In this review, we discuss the recent findings of all 27 available head-to-head trials investigating the efficacy and safety of systemic and biologic therapies in moderate-to-severe psoriasis vulgaris, as it is thought to provide more useful knowledge than placebo intervention alone. According to our evaluation, inhibitors that specifically target IL-23 or IL-17 are clinically more beneficial than inhibitors of IL-12/IL-23 and TNF. More informative results might be obtained by comparing these more efficient biological agents to each other. In addition, newer therapies for psoriasis using small-molecule drugs may represent important advances compared to well-established biologics as these are less expensive and orally administered.