Ustekinumab in psoriatic arthritis and related phenotypes

Psoriatic arthritis (PsA) is an inflammatory arthritis that commonly occurs with psoriasis and is attributed to genetic, immunologic and environmental factors. The T-helper (Th)-17 pathway and the interleukin (IL)-23/IL-17 axis have become prominent players in PsA and considerably increased our understanding of disease pathogenesis. In this review article, we will focus on the emerging role of IL-12/23 and its blockade, in the pathogenesis and management of PsA as well as of psoriasis and inflammatory bowel disease. Ustekinumab, is a fully human monoclonal immunoglobulin (Ig)G1 antibody that binds specifically to the p40 subunit of IL-12 and IL-23, primarily inhibiting downstream Th-17 signalling pathways. Ustekinumab produced consistent and sustained clinical efficacy in two phase III clinical trials in PsA, PSUMMIT-1 and PSUMMIT-2, with data out to 52 weeks, and no new safety signals. PSUMMIT-1 included patients with active PsA despite conventional therapy who were all naive to anti-tumour necrosis fact...