SUMMARY

• The company cannot recommend any practices, procedures, or usage that deviate from the approved labeling.
• APEX was designed to evaluate the clinical, radiographic, and safety outcomes of TREMFYA in a phase 3b, randomized, double-blind, placebo-controlled study in biologic-naïve patients with active psoriatic arthritis (PsA) and known risk factors for radiographic progression. Results are available through week 24 in this ongoing study.^1,2 
• The primary endpoint was the proportion of the patients who achieved ≥20% improvement from baseline in the American College of Rheumatology Criteria (ACR20) at week 24. Results were significantly greater in both TREMFYA groups compared to placebo (ACR20: TREMFYA every 4 weeks [q4w], 66.6% and TREMFYA every 8 weeks [q8w], 68.3% vs placebo, 47.0%; P<0.001 and P<0.001, respectively).^1,3 
• At week 24, for the major secondary endpoint of least square (LS) mean change from baseline in total PsA-modified van der Heijde-Sharp (vdH-S) score, patients in both TREMFYA groups exhibited significantly less radiographic progression compared to those in the placebo group (LS mean changes in PsA-modified vdH-S score: TREMFYA q4w, 0.55 and TREMFYA q8w, 0.54, vs placebo, 1.35; P=0.002 and P<0.001, respectively).^1,3
• Through week 24, adverse events (AEs), serious adverse events (SAEs), infection rates, and serious infection rates were reported as follows:^1,3
  • AEs occurred in 38.2% (107/280) and 42.5% (165/388) of patients in the TREMFYA q4w and q8w groups, respectively vs 37.3% (144/386) in the placebo group.
  • SAEs occurred in 1.8% (5/280) and 3.1% (12/388) of patients in the TREMFYA q4w and q8w groups, respectively vs 2.6% (10/386) in the placebo group.
  • Infection rates were reported at 18.6% (52/280) and 23.5% (91/388) of patients in the TREMFYA q4w and q8w groups, respectively vs 21.0% (81/386) in the placebo group.
  • Serious infection rates were reported at 0.7% (2/280) and 1.3% (5/388) of patients in the TREMFYA q4w and q8w groups, respectively vs 0.3% (1/386) in the placebo group.

CLINICAL STUDY

Phase 3b Study – APEX

Mease et al (2025)^1,3 reported the clinical, radiographic, and safety outcomes of TREMFYA compared with placebo in biologic-naïve patients with active PsA and known risk factors for radiographic progression in an ongoing phase 3b, randomized, double-blind, placebo-controlled study.

Study Design/Methods

• Select inclusion criteria:^2,4
  • Age ≥18 years old
  • Diagnosis of PsA for ≥6 months and met ClASsification criteria for Psoriatic ARthritis (CASPAR) at screening
  • Active PsA (despite previous conventional synthetic disease-modifying antirheumatic drugs [csDMARD], apremilast, and/or nonsteroidal anti-inflammatory drug [NSAID] therapy): ≥3 swollen/tender joints and CRP ≥0.3 mg/dL
  • ≥2 joints with erosions on baseline radiographs of the hands and feet
  • Active plaque psoriasis (PsO), with ≥1 psoriatic plaque of ≥2 cm diameter and/or nail changes consistent with PsO
• Select exclusion criteria:
  • Previous biologic or Janus kinase inhibitor therapy
  • Currently receiving ≥3 csDMARDs
• The study design is summarized in Figure: APEX Study Design.

• Multiplicity-controlled endpoints:^1,3   
  • Primary endpoint: ACR20 response at week 24
  • Major secondary endpoint: mean change from baseline in total PsA-modified vdH-S score at week 24
• Non-controlled endpoints:
  • Proportion of patients achieving ACR50 and ACR70 responses at week 24
  • Other endpoints at week 24 included LS mean changes from baseline in erosion score and joint space narrowing (JSN) score, the proportions of patients with a change in PsA-modified vdH-S score of ≤0.5 and ≤0, the proportion of patients achieving Investigator’s Global Assessment (IGA) 0/1 response, the proportion of patients achieving ≥90% improvement from baseline in Psoriasis Area Severity Index (PASI 90) score, and LS mean change from baseline in Health Assessment Questionnaire-Disability Index (HAQ-DI).
• The modified full analysis set (mFAS) was defined as all randomized patients excluding those from Ukraine sites rendered unable to support key study operations due to major disruptions (main efficacy analysis set).
• Safety analyses included all patients who received ≥1 dose of study treatment through week 24.
• Statistical methods:² 
  • Cochran-Mantel-Haenszel test and analysis of covariance will compare treatment efficacy for the primary and major secondary endpoints, respectively.
  • Statistical testing will be performed using 2-sided tests. Overall type I error of the hypotheses will be controlled at a significance level of ≤0.05 and will be tested in a fixed sequence.

Results

Patient Characteristics

• A total of 1054 patients were enrolled and randomized.¹
  • The mFAS included 1020 patients.
  • The safety analysis set included all 1054 patients randomized.
• Select baseline characteristic are summarized in Table: Select Baseline Characteristics.

Efficacy

• The results for the primary, major secondary, and other endpoints at week 24 are summarized in the following tables:
  • Summary of Primary, Major Secondary, and Other Endpoints at Week 24 in the Completed mFAS
  • Summary of IGA 0/1 and PASI 90 Responses at Week 24
  • Summary of HAQ-DI Response at Week 24

Safety

• The results for the safety profile through week 24 are summarized in Table: Summary of Safety Profile Through Week 24.

• The most common AEs were respiratory infections, headache, diarrhea, and psoriatic arthropathy.³ 

Literature Search

A literature search of MEDLINE^®, EMBASE^®, BIOSIS Previews^®, and DERWENT^® (and/or other resources, including internal/external databases) was conducted on 15 June 2025.