IL17A and palmoplantar pustulosis: ,21 Furthermore, several biologics, known to be highly effective in PV, such as inhibitors of IL-12/IL-23, TNF-α, and IL-17A,4 did not show sufficient efficacy in PPP.22, 23, 24, 25 For example, ustekinumab (anti-IL-12/IL-23 monoclonal antibody) and secukinumab (anti-IL-17A monoclonal antibody) failed to reach the primary efficacy endpoint in a small-size and a phase-3b randomized placebo-controlled trial, respectively, in patients with PPP.23