Focus on biosimilar etanercept - bioequivalence and interchangeability

Area of Science:

• Rheumatology
• Pharmacoeconomics
• Immunology

Background:

• Reference etanercept (re-ETN) biosimilars (SB4, GP2015, HD203) have been approved, offering significant cost savings for rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis management.
• The lower cost of these biosimilars presents an opportunity for substantial healthcare savings.

Purpose of the Study:

• To review the pharmacodynamics, pharmacokinetics, efficacy, and safety of etanercept biosimilars.
• To assess their suitability as first-line therapy versus after transitioning from re-ETN.
• To address patient and rheumatologist acceptability of biosimilar use and switching.

Main Methods:

• Literature review of PubMed and major rheumatology conference abstracts.
• Analysis of regulatory agency approvals based on bioequivalence studies (pharmacodynamics, pharmacokinetics, head-to-head trials).
• Evaluation of evidence regarding extrapolation of indications and interchangeability.

Main Results:

• Biosimilars SB4, GP2015, and HD203 demonstrated bioequivalence to re-ETN, leading to approval for all re-ETN indications.
• Extrapolation of indications and interchangeability raised concerns among rheumatologists due to limited switching data.
• Switching from re-ETN to biosimilars resulted in discontinuation rates of 7%-17% and a patient desire for more information (20%-30%).

Conclusions:

• Etanercept biosimilars are a viable option for initial treatment in relevant inflammatory conditions.
• Further research is required to fully establish the efficacy, safety, and economic impact of transitioning patients from reference etanercept to biosimilars.