Palmoplantar psoriasis (PPP) is notoriously hard to treat. PPP presents with erythematous, scaling plaques, fissures, and sterile pustules on the palms and soles that cause significant pain and morbidity. Risk factors include a genetic predisposition, smoking, and female sex.
Management is difficult, with results that are often disappointing and unpredictable. Traditional treatments—ultrapotent topical corticosteroids, oral retinoids, methotrexate, cyclosporine, and phototherapy (UVB or PUVA)—typically only lead to partial improvement.
The IL-23/17 proinflammatory cytokine pathway is important in the pathogenesis of both psoriasis vulgaris and PPP. Guselkumab, a humanized monoclonal antibody to the p19 protein subunit of IL-23, has been shown to be very effective in clearing moderate to severe chronic plaque psoriasis when compared with placebo and the TNF-alpha blocker adalimumab. A small pilot study of this agent conducted in Japanese patients with PPP also found promising results.
Spurred on by these encouraging findings, the Japanese investigators launched a phase 3, randomized, crossover trial to confirm the safety and efficacy of guselkumab as a monotherapy for PPP.
This larger study enrolled 159 Japanese patients with PPP (mean age, 53.3 years; 79.2% female). Participants were randomly assigned to receive placebo, guselkumab 100 mg, or guselkumab 200 mg subcutaneously at weeks 0, 4, 12, and then every 8 weeks for a total of 60 weeks. At week 16, those in the placebo group crossed over to receive guselkumab.
