Clinical improvement in psoriasis with specific targeting of interleukin-23

A proof-of-concept phase I clinical trial demonstrates that targeting interleukin (IL)-23 with an antibody that binds to the p19 subunit leads to clinical improvement of disease in patients with moderate to severe psoriasis. Sauzanne Khalilieh and colleagues report a proof-of-concept phase I clinical trial which demonstrates that targeting the pro-inflammatory cytokine interleukin-23 (IL-23) with tildrakizumab, an antibody that binds to the p19 subunit of IL-23, leads to symptomatic improvement of disease in patients with moderate to severe psoriasis. The antibody is well tolerated, suggesting that selective targeting of IL-23 merits further study. Psoriasis is a chronic inflammatory skin disorder that affects approximately 2–3% of the population worldwide and has severe effects on patients’ physical and psychological well-being1,2,3. The discovery that psoriasis is an immune-mediated disease has led to more targeted, effective therapies; recent advances have focused on the interleukin (IL)-12/23p40 subunit shared by IL-12 and IL-23. Evidence suggests that specific inhibition of IL-23 would result in improvement in psoriasis. Here we evaluate tildrakizumab, a monoclonal antibody that targets the IL-23p19 subunit, in a three-part, randomized, placebo-controlled, sequential, rising multiple-dose phase I study in patients with moderate-to-severe psoriasis to provide clinical proof that specific targeting of IL-23p19 results in symptomatic improvement of disease severity in human subjects. A 75% reduction in the psoriasis area and severity index (PASI) score (PASI75) was achieved by all subjects in parts 1 and 3 (pooled) in the 3 and 10 mg kg−1 groups by day 196. In part 2, 10 out of 15 subjects in the 3 mg kg−1 group and 13 out of 14 subjects in the 10 mg kg−1 group achieved a PASI75 by day 112. Tildrakizumab demonstrated important clinical improvement in moderate-to-severe psoriasis patients as demonstrated by improvements in PASI scores and histological samples.