Patient-Reported Outcome Measures in Patients with Rheumatoid Arthritis, Psoriasis, or Psoriatic Arthritis Treated with GP2015
Patient-Reported Outcome Measures in Patients with Rheumatoid Arthritis, Psoriasis, or Psoriatic Arthritis Treated with GP2015, an Etanercept Biosimilar: Results from Two Phase III Studies (EGALITY and EQUIRA)
Thaçi D, Gerdes S, Schulze-Koops H, Allanore Y, Kavanaugh A, Both C, Gattu S, Hachaichi S, Matucci-Cerinic M. Drugs R D. 2025 Jun;25(2):107-115. doi: 10.1007/s40268-025-00507-8. PMID: 40279006; PMCID: PMC12185822.
Introduction
Rheumatoid arthritis (RA), psoriasis (PsO), and psoriatic arthritis (PsA) are chronic immune-mediated inflammatory conditions significantly impacting patients’ quality of life and daily function. Biologic therapies, specifically tumor necrosis factor (TNF) inhibitors like etanercept, have revolutionized disease management by targeting underlying pathophysiology.
Biosimilars, such as GP2015, offer a cost-effective alternative to reference biologics while maintaining comparable efficacy and safety profiles. Understanding patient-reported outcomes (PROs) when treating with biosimilars versus reference products is essential for holistic assessment of therapeutic benefit across multiple domains, including physical function, fatigue, and quality of life.
Study Overview
Design and Patient Populations
EGALITY Study: A Phase III randomized controlled trial enrolling 531 patients with moderate-to-severe chronic plaque-type psoriasis, some with reported psoriatic arthritis.
Eligible patients achieving ≥50% improvement in Psoriasis Area and Severity Index (PASI) at week 12 either continued initial treatment or underwent three planned treatment switches between GP2015 and reference etanercept (ref-ETN) starting at week 12.
EQUIRA Study: Phase III trial including 376 patients with rheumatoid arthritis.
Patients demonstrating at least a moderate European League Against Rheumatism (EULAR) response at week 24 continued GP2015 treatment up to week 48.
Patient-Reported Outcome Measures
- EGALITY: Dermatology Life Quality Index (DLQI), EuroQol five-dimension health status questionnaire (EQ-5D-5L), and Health Assessment Questionnaire–Disability Index (HAQ-DI) for those with psoriatic arthritis.
- EQUIRA: Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue score and HAQ-DI.
Key Findings
- EGALITY (Psoriasis and Psoriatic Arthritis): Mean DLQI percent reductions from baseline at week 12 were similar between GP2015 (-67.7%) and reference etanercept (-67.3%), with sustained improvements through week 52 after treatment switching.
- EQ-5D-5L assessments showed increased proportions of patients reporting ‘no problems’ across all five dimensions by week 52, with comparable results between treatments.
- HAQ-DI scores in patients with baseline PsA improved significantly and similarly in both groups, and gains were maintained after switching.
- EQUIRA (Rheumatoid Arthritis): HAQ-DI scores normalized (≤ 0.5) comparably between continuous and switched GP2015 patients at week 48 (36.7% vs 39.9%).
- FACIT-Fatigue scores improved meaningfully with sustained changes observed through week 48 following switching.
Evidence Synthesis and Related Research
The PRO data from the EGALITY and EQUIRA trials consistently demonstrate that the etanercept biosimilar GP2015 achieves similar patient-centered clinical benefits as the reference product across RA, PsA, and PsO. Improvements in quality-of-life scales, physical function, and fatigue were not compromised by switching between products, supporting the interchangeable use of biosimilars.
| Study / Author | Summary of Findings and Clinical Context |
|---|---|
| Thaçi et al., 2025 (EGALITY & EQUIRA) | Confirmed GP2015 matched ref-ETN in PRO improvements including DLQI, EQ-5D-5L, HAQ-DI, and FACIT-Fatigue scores across three immune-mediated diseases. Switching between biosimilar and originator showed sustained outcomes. (PMID: 40279006) |
| General Clinical Guidelines | Support biosimilar etanercept use for moderate-to-severe RA, PsA, and PsO, emphasizing cost-effectiveness without sacrificing efficacy or patient quality-of-life. |
| Current Literature Gap | While meta-analyses and real-world data validate biosimilar interchangeability, high-quality RCTs like EGALITY and EQUIRA remain the gold standard for demonstrating patient-reported clinical equivalence. |
Clinical Implications
- GP2015 provides equivalent patient-reported improvements in quality of life and physical function compared with reference etanercept, supporting its use as an effective biosimilar alternative.
- Switching between biosimilar and originator does not negatively impact patient outcomes, reassuring clinicians and patients regarding therapeutic interchangeability.
- Use of validated PRO tools like DLQI, HAQ-DI, and FACIT-Fatigue enhances comprehensive assessment beyond clinical measures.
Strengths & Limitations
| Strengths | Limitations |
|---|---|
| Large randomized controlled trials including over 900 patients total across distinct immune-mediated disease populations. | Absence of detailed statistical analyses (e.g., p-values or confidence intervals) comparing PROs between treatment arms limits precision of equivalence assessment. |
| Comprehensive assessment of multiple validated patient-reported outcomes capturing quality of life, physical function, and fatigue. | Short to mid-term follow-up limited to 52 weeks; longer-term safety and immunogenicity data remain essential. |
| Inclusion of treatment switching arms allowed evaluation of interchangeability in real-world mimicking conditions. | Data primarily from trial settings may not fully reflect real-world diverse patient experiences or adherence patterns. |
Future Directions
Additional studies are needed to evaluate long-term safety, immunogenicity, and real-world effectiveness of GP2015. Research on patient-centered outcomes covering diverse populations and comparative effectiveness with other biosimilars will further optimize personalized treatment strategies.
Conclusion
GP2015, an etanercept biosimilar, provides comparable patient-reported outcomes and quality-of-life improvements to reference etanercept across rheumatoid arthritis, psoriasis, and psoriatic arthritis, with sustained benefits even after switching.
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References
- Thaçi D, Gerdes S, Schulze-Koops H, Allanore Y, Kavanaugh A, Both C, Gattu S, Hachaichi S, Matucci-Cerinic M. Patient-Reported Outcome Measures in Patients with Rheumatoid Arthritis, Psoriasis, or Psoriatic Arthritis Treated with GP2015, an Etanercept Biosimilar: Results from Two Phase III Studies (EGALITY and EQUIRA). Drugs R D. 2025 Jun;25(2):107-115. doi: 10.1007/s40268-025-00507-8. Epub 2025 Apr 25. PMID: 40279006; PMCID: PMC12185822.
