Interleukin-23 (IL-23) is a crucial regulatory cytokine in psoriasis, that is involved in the differentiation, proliferation, and survival of T-helper 17 (Th17) cells. Specifically targeting the IL-23–IL-17 inflammatory pathway is an effective therapeutic approach for treating psoriasis. IL 17 and IL-23 blockers have obtained almost PASI 100 responses. Clinical studies have indicated that directing antibodies against the p19 subunit of IL-23 renders an equal or even superior response than when inhibiting both IL-12 and IL-23. Furthermore, the side effects of IL-12 inhibition are also bypassed. 

The examples of antibodies that target the p19 subunit of IL-23 are Tildrakizumab, guselkumab, and risankizumab. These newer IL-23 blockers are famed to render high PASI response and are easy to administer once in 8–12 weeks.

PASI 75 has now become the new norm. These recently approved IL 17 and IL-23 blocking monoclonal antibodies are highly efficient and have a good safety profile, as proven in short-term clinical trials. However, only long-term results from clinical studies and post-marketing surveillance will decide their success. 

Guidance on the most suitable biologics for achieving the highest rate of success for the individual patient, and how to proceed or discontinue treatment in patients that have achieved effect on biologics is warranted. Future studies describing the correlation between genetics, co-morbidities, and psoriasis will aid in individualizing the treatment approach.

Source- Parasramani SG, Shirolikar M. IL-23 blockers in dermatology. Indian J Drugs Dermatol 2021;7:51-9