The competition among latecomers is intensifying in the interleukin inhibitor market with the scope of their indications expanding to psoriatic arthritis.

The leader in this market is Janssen’s IL-12/23 inhibitor, ‘Stelara (Ustekinumab).’ Although 10 years have passed since its approval, the drug still boasts a growth rate in the 30% range. Based on IQVIA, sales of Stelara recorded ₩36.1 billion last year.

Janssen’s new goal in the market is to successfully make a generation change and replace Stelara with its follow-up drug, ‘Tremfya (guselkumab),' the first-in-class IL-23 inhibitor that was released in Korea in 2018. However, Tremfya is being challenged in the market by the seco