Trial results for a Phase 3 study (NCT06039189) investigating guselkumab for low body surface area moderate plaque psoriasis were posted on ClinicalTrials.gov on 2026-05-01. The study showed that 74.2% of participants receiving guselkumab 100 mg achieved an Investigator's Global Assessment (IGA) score of cleared (0) or minimal (1) at Week 16, compared to 12.4% for those on placebo.
Background
The study evaluated guselkumab for the treatment of low body surface area moderate plaque psoriasis with special site involvement.
Trial design
The study (NCT06039189) was a Phase 3, randomized, placebo-controlled trial that enrolled 338 participants. It investigated guselkumab 100 mg compared to placebo in participants with moderate plaque psoriasis, specifically those with low body surface area and special site involvement.
Key results
The trial results demonstrated significant improvements in participants treated with guselkumab 100 mg compared to placebo at Week 16 across multiple efficacy endpoints.
- For the "Percentage of Participants Who Achieved an Investigator's Global Assessment (IGA) Score of Cleared (0) or Minimal (1) at Week 16," 74.2% of participants in the guselkumab 100 mg group achieved this outcome, compared to 12.4% in the placebo group. The adjusted treatment difference was 61.8 (95.0% CI: 53.4 to 70.1) with a p-value of 0.001.
- Regarding "Percent Change From Baseline in Body Surface Area (BSA) at Week 16," participants on guselkumab 100 mg showed a mean change of -80.5% (Standard Deviation: 27.78), while the placebo group showed a mean change of -5.6% (Standard Deviation: 54.33). The Least Square (LS) Mean Difference was -74.48 (95.0% CI: -83.33 to -65.62) with a p-value of 0.001.
- For "Percent Change From Baseline in Psoriasis Area Severity Index (PASI) Total Score at Week 16," the guselkumab 100 mg group achieved a mean change of -82.6% (Standard Deviation: 24.24), versus -13.6% (Standard Deviation: 50.78) for the placebo group. The LS Mean Difference was -68.96 (95.0% CI: -77.06 to -60.87) with a p-value of 0.001.
- For "Percentage of Participants Who Achieved IGA Score of Cleared (0) at Week 16," 40.4% in the guselkumab 100 mg group achieved this, compared to 3.5% in the placebo group. The adjusted treatment difference was 36.9 (95.0% CI: 29.6 to 44.1) with a p-value of 0.001.
- For "Percentage of Participants Who Achieved PASI 90 Response at Week 16," 52.9% in the guselkumab 100 mg group achieved this, versus 6.2% in the placebo group. The adjusted treatment difference was 46.6 (95.0% CI: 38.8 to 54.5) with a p-value of 0.001.
- For "Percentage of Participants Who Achieved PASI 100 Response at Week 16," 32.4% in the guselkumab 100 mg group achieved this, compared to 2.7% in the placebo group. The adjusted treatment difference was 29.7 (95.0% CI: 23.0 to 36.5) with a p-value of 0.001.
What this means
The results from this Phase 3 trial indicate that guselkumab 100 mg significantly improved outcomes for participants with low body surface area moderate plaque psoriasis compared to placebo. The substantial differences observed across key endpoints such as IGA 0/1, BSA reduction, and PASI scores suggest that guselkumab could be an effective treatment option for this specific patient population, potentially offering a new therapeutic strategy for those with moderate plaque psoriasis affecting limited body areas but with special site involvement.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT06039189, titled "Study of Guselkumab Versus Placebo for the Treatment of Low Body Surface Area Moderate Plaque Psoriasis," were posted on 2026-05-01 on clinicaltrials.gov.