Results from a Phase 4 trial investigating guselkumab in patients with psoriasis were posted on 2026-06-23. The study, titled 'Guselkumab Immunogenetics,' reported a mean decrease of 5.7% in lesional CD4+ T effector cells in new-onset guttate psoriasis patients. It also observed increases in lesional CD8+ T effector cells in both guttate and chronic plaque psoriasis.
Background
Guselkumab (Tremfya) is an established treatment for psoriasis. This Phase 4 study focused on understanding the immunogenetic responses of patients with either plaque or guttate psoriasis when treated with guselkumab.
Trial design
This was a Phase 4, two-arm open-label study (NCT04645355) that enrolled 17 participants. The study evaluated patients diagnosed with either Psoriasis Guttate or Plaque Psoriasis. The brief summary indicated the study aimed to evaluate clinical and immunogenetic responses to guselkumab treatment.
Key results
The trial reported several key measurements regarding changes in lesional T effector cells:
- For Lesional CD4+ T Effector Cells in the New-onset Guttate Psoriasis group, there was a mean absolute change of -5.7% (Standard Deviation: 13.5%) in Th17 cells.
- For Lesional CD4+ T Effector Cells in the Chronic Plaque Psoriasis group, there was a mean absolute change of 0.9% (Standard Deviation: 23.4%) in Th17 cells.
- For Lesional CD8+ T Effector Cells in the New-onset Guttate Psoriasis group, there was a mean absolute change of 9.1% (Standard Deviation: 17.2%) in Th17 cells.
- For Lesional CD8+ T Effector Cells in the Chronic Plaque Psoriasis group, there was a mean absolute change of 12.5% (Standard Deviation: 12.9%) in Th17 cells.
What this means
The results from this immunogenetic study provide insights into how guselkumab treatment may modulate T-cell populations in the skin of psoriasis patients. The observed mean decrease in lesional CD4+ T effector cells in new-onset guttate psoriasis suggests a potential impact on this specific T-cell subset in this patient group. Conversely, the increases in lesional CD8+ T effector cells in both guttate and chronic plaque psoriasis indicate a differential or broader effect on the immune microenvironment. These findings contribute to a deeper understanding of guselkumab's immunomodulatory effects beyond its primary mechanism, particularly in different forms of psoriasis, which could inform future research or personalized treatment strategies.
Source
The trial results were posted on 2026-06-23 on ClinicalTrials.gov, an official database of clinical studies. The full details are available on clinicaltrials.gov under the identifier NCT04645355.