Guselkumab for the treatment of palmoplantar pustulosis.

INTRODUCTION: Palmoplantar pustulosis, or pustulosis palmaris et plantaris (PPP), is a chronic, recurrent inflammatory skin disease that is sometimes unresponsive to conventional therapy. The anti-interleukin 23 antibody guselkumab is effective for treating PPP. AREAS COVERED: This review details the current understanding of PPP and discusses why guselkumab may be effective. Guselkumab is only approved for the treatment of PPP in Japan. In the United States, Canada, the European Union, and several other countries, it is approved for the treatment of moderate-to-severe plaque psoriasis, but not for PPP. Furthermore, guselkumab was approved only 1 year ago; its efficacy will be proven only by phase 2 and 3 clinical trials. EXPERT OPINION: The first double-blinded randomized placebo-controlled trial (RCT) of guselkumab for PPP has been completed. The drug was effective, and guselkumab could be used as a new agent for PPP treatment, in addition to several conventional therapeutics. However, several issues remain. For example, there is no mouse model of PPP, so careful observation of human PPP patients and establishment of a good experimental PPP model are essential.