Trial results for a Phase 3 study investigating guselkumab in participants with active psoriatic arthritis were posted on ClinicalTrials.gov on 2026-02-04. The study demonstrated that 68.3% of participants receiving guselkumab 100 mg every 8 weeks achieved an ACR20 response at Week 24, significantly outperforming the 47.0% in the placebo group.
Background
The trial investigated guselkumab for the treatment of active psoriatic arthritis (PsA), a chronic inflammatory condition affecting the joints.
Trial design
The study (NCT04882098) was a Phase 3, randomized, placebo-controlled trial. It enrolled 1054 participants with active psoriatic arthritis. The trial aimed to evaluate the efficacy of guselkumab treatment by assessing the reduction in signs and symptoms of PsA. Participants were assigned to receive either guselkumab or placebo.
Key results
The trial evaluated two primary efficacy endpoints. For the "Percentage of Participants Who Achieved an American College of Rheumatology (ACR) 20 Response at Week 24":
- Participants receiving guselkumab 100 mg every 8 weeks achieved an ACR20 response of 68.3%.
- Participants receiving guselkumab 100 mg every 4 weeks achieved an ACR20 response of 66.6%.
- The placebo group achieved an ACR20 response of 47.0%.
Statistical analysis showed a difference in percentage of 21.3% (95.0% CI: 14.4 to 28.2) for guselkumab 100 mg every 8 weeks versus placebo, with a p-value of 0.001. For guselkumab 100 mg every 4 weeks versus placebo, the difference was 19.7% (95.0% CI: 12.1 to 27.2), with a p-value of 0.001.
For the "Change From Baseline in Psoriatic Arthritis (PsA) Modified Van Der Heijde-Sharp (vdH-S) Total Score at Week 24":
- The guselkumab 100 mg every 8 weeks group showed a Least Squares Mean change of 0.54.
- The guselkumab 100 mg every 4 weeks group showed a Least Squares Mean change of 0.55.
- The placebo group showed a Least Squares Mean change of 1.35.
Statistical analysis indicated a Least Square Mean Difference of -0.8 (95.0% CI: -1.28 to -0.33) for guselkumab 100 mg every 8 weeks versus placebo, with a p-value of 0.001. For guselkumab 100 mg every 4 weeks versus placebo, the difference was -0.8 (95.0% CI: -1.31 to -0.28), with a p-value of 0.002.
What this means
The results indicate that both dosing regimens of guselkumab significantly improved the signs and symptoms of active psoriatic arthritis, as evidenced by the superior ACR20 response rates compared to placebo. Furthermore, the lower change from baseline in the vdH-S total score suggests that guselkumab may also reduce the progression of structural joint damage in this patient population. These findings support the potential of guselkumab as an effective treatment option for individuals with active psoriatic arthritis.
Source
The information for this article was obtained from ClinicalTrials.gov, a public database of clinical studies. The trial results for study NCT04882098, titled "A Study of Guselkumab in Participants With Active Psoriatic Arthritis," were posted on 2026-02-04 on clinicaltrials.gov.