Generalized pustular psoriasis: current management status and unmet medical needs in Japan

Generalized pustular psoriasis (GPP) is a rare, inflammatory skin disease characterized by recurrent flares of pustulation accompanied by systemic symptoms that can be life-threatening. The clinical and humanistic burden of GPP in Japan is high, and it is a designated intractable disease. We reviewed clinical evidence and guidelines for GPP treatment in Japan to identify unmet needs and assess data supporting the development and use of new targeted therapies.

Using specific search terms in PubMed and Embase, with additional back-referencing, we retrieved literature related to GPP in Japan focusing on clinical and pathogenic characteristics, diagnosis, and treatment.

Although there are approved systemic therapies for GPP in Japan, all present uncertainties in terms of safety and efficacy. Clinical evidence supporting their use comes mostly from studies in patients with mild or moderate disease, and their effectiveness in treating acute phase GPP is unknown. The interleukin-36 pathway appears to be central to GPP pathogenesis. New therapies targeting this pathway show promise in patients presenting with acute phase GPP. The rarity and intermittent course of GPP make it challenging to recruit sufficient patients for trials and robustly investigate the efficacy and safety of these agents to treat GPP.