Guselkumab clears skin in children with moderate-to-severe plaque psoriasis in phase III trial

Guselkumab, sold as TREMFYA, has expanded the systemic treatment options available for children and adolescents with moderate-to-severe plaque psoriasis, according to a profile of its use published in Drugs & Therapy Perspectives. The drug is a first-in-class interleukin-23 (IL-23) antagonist, a monoclonal antibody that binds selectively to the p19 subunit of IL-23 and blocks the IL-23-mediated inflammatory signalling involved in psoriasis.

In the European Union, guselkumab is approved for paediatric patients aged 6 years and older who are candidates for systemic therapy for moderate-to-severe plaque psoriasis. In the United States, the approval covers paediatric patients aged 6 years and older who weigh at least 40 kg and are candidates for systemic therapy or phototherapy.

The efficacy evidence comes from the randomized, placebo-controlled, multicentre, phase III PROTOSTAR trial. At week 16 of treatment, subcutaneous guselkumab significantly reduced disease severity compared with placebo, meeting all co-primary and key secondary endpoints. These endpoints related to Investigator Global Assessment scores, reflecting clear or almost clear skin, and to Psoriasis Area and Severity Index scores showing at least 75%, 90% or 100% improvement from baseline.

The trial also measured improvements in patient quality of life, which were greater with guselkumab than with placebo. In a plain language summary accompanying the article, the authors note that treatment with guselkumab resulted in completely or mostly cleared skin in significantly more patients than placebo in the 52-week clinical trial in children and adolescents aged 6 years and older with moderate-to-severe plaque psoriasis.

Benefits were seen up to week 52 in a guselkumab crossover, withdrawal and re-treatment period, as well as in a 52-week open-label continuous guselkumab treatment period. This design allowed researchers to observe the effects of continuous treatment and of withdrawal and re-treatment over a full year of follow-up.

Guselkumab was generally well tolerated in the trial. The most common adverse events were infections, most frequently nasopharyngitis and upper respiratory tract infection, and headache. The profile states that these findings support the drug’s tolerability in this paediatric population.

Plaque psoriasis is a chronic, inflammatory skin condition in which about a third of cases arise in childhood. It is managed with topical therapies, light therapy and/or systemic treatments, which may be non-biologic or biologic. Guselkumab is the first IL-23 blocker approved to treat moderate-to-severe plaque psoriasis in children and adolescents aged 6 years and older who are eligible to receive systemic and/or light therapy.

By selectively targeting the p19 subunit of IL-23, guselkumab interrupts a specific inflammatory pathway implicated in psoriasis, distinguishing it within the broader class of biologic therapies used for the condition. Its paediatric approval adds a targeted biologic option for young patients whose disease requires more than topical treatment alone.

According to the profile, guselkumab expands the systemic treatment options available for children and adolescents aged 6 years and older with moderate-to-severe plaque psoriasis, with the PROTOSTAR trial providing the pivotal evidence of significant disease severity reduction, quality-of-life improvement and generally good tolerability up to one year of treatment.

Subject of Research: Use of the IL-23 antagonist guselkumab for treating moderate-to-severe plaque psoriasis in children and adolescents

Article Title: Guselkumab in paediatric plaque psoriasis: a profile of its use

Article References: Kang, C. (2026). Guselkumab in paediatric plaque psoriasis: a profile of its use. Drugs & Therapy Perspectives. https://doi.org/10.1007/s40267-026-01275-4

Image Credits: AI Generated

DOI: 10.1007/s40267-026-01275-4

Keywords: guselkumab, plaque psoriasis, paediatric psoriasis, IL-23 antagonist, PROTOSTAR trial, monoclonal antibody, biologic therapy, phase III trial, skin disease, systemic treatment, paediatric, plaque