Primary completion results for a Phase 3 study evaluating guselkumab (Tremfya) in participants with active psoriatic arthritis were posted on ClinicalTrials.gov on 2019-02-25. The trial demonstrated that guselkumab 100 mg q8w led to a 64.1% ACR20 response rate at Week 24, compared to 32.9% for the placebo group, a statistically significant difference of 31.2% (95% CI: 22.9%, 39.5%; p=0.001).
Background
Guselkumab (Tremfya) is an investigational treatment for psoriatic arthritis (PsA), a chronic inflammatory disease affecting joints and skin. PsA is often associated with psoriasis, causing pain, stiffness, and swelling in and around the joints, as well as skin lesions.
Trial design
The Phase 3 study (NCT03158285) enrolled 741 participants with active psoriatic arthritis. The primary purpose of the study was to evaluate the efficacy and safety of guselkumab administered subcutaneously, assessing the reduction in signs and symptoms of PsA. Participants were randomized to receive either guselkumab 100 mg q8w, guselkumab 100 mg q4w, or placebo.
Key results
The trial reported key efficacy results at Week 24:
- For American College of Rheumatology (ACR) 20 response:
- Guselkumab 100 mg q8w achieved an ACR20 response in 64.1% of participants, and guselkumab 100 mg q4w in 63.7%, compared to 32.9% for placebo.
- The difference in percentage for guselkumab 100 mg q8w versus placebo was 31.2% (95% CI: 22.9%, 39.5%; p=0.001).
- The difference for guselkumab 100 mg q4w versus placebo was 30.8% (95% CI: 22.4%, 39.1%; p=0.001).
- For change from baseline in Health Assessment Questionnaire-Disability Index (HAQ-DI) Score:
- The least squares mean change was -0.3672 units for guselkumab 100 mg q8w and -0.4004 units for guselkumab 100 mg q4w, compared to -0.1300 units for placebo.
- The least square mean difference for guselkumab 100 mg q8w versus placebo was -0.2372 units (95% CI: -0.321, -0.1534; p=0.001).
- For guselkumab 100 mg q4w versus placebo, the difference was -0.2704 units (95% CI: -0.3544, -0.1864; p=0.001).
- For ACR 50 response:
- Guselkumab 100 mg q8w showed a 31.5% response rate, and guselkumab 100 mg q4w showed 33.1%, compared to 14.2% for placebo.
- The difference in percentage for guselkumab 100 mg q8w versus placebo was 17.2% (95% CI: 10.0%, 24.4%; p=0.001).
- The difference in percentage for guselkumab 100 mg q4w versus placebo was 18.8% (95% CI: 11.5%, 26.1%; p=0.001).
- For Psoriasis Response with IGA Score of 0 or 1 and >=2 Grade Reduction from Baseline:
- Guselkumab 100 mg q8w achieved this response in 70.5% of participants, and guselkumab 100 mg q4w in 68.5%, versus 19.1% for placebo.
What this means
The results from this Phase 3 trial indicate that guselkumab significantly improved signs and symptoms of psoriatic arthritis compared to placebo at Week 24. Both the 100 mg q8w and 100 mg q4w dosing regimens showed substantial increases in ACR20 and ACR50 response rates, as well as clinically meaningful reductions in HAQ-DI scores, suggesting an improvement in physical function. The strong response in IGA scores also highlights guselkumab's efficacy in addressing the skin manifestations of psoriatic arthritis. These positive findings support the potential of guselkumab as an effective treatment option for patients with active psoriatic arthritis.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for the study NCT03158285, titled "A Study Evaluating the Efficacy and Safety of Guselkumab Administered Subcutaneously in Participants With Active Psoriatic Arthritis", were posted as primary completion on 2019-02-25 on clinicaltrials.gov.