Erelzi: A Biosimilar TNF Inhibitor
Erelzi, known generically as etanercept-szzs, is a biologic medicine created through recombinant DNA technology using living cells. It is classified as a biosimilar, meaning it is highly similar to the FDA-approved biologic Enbrel (etanercept) with no clinically significant differences in safety, purity, and potency. The development of biosimilars like Erelzi can provide more affordable alternatives to brand-name biologics. Rigorous testing, including laboratory and clinical studies, is required for biosimilar approval to confirm its similarity and equivalent effectiveness to the reference product.
Mechanism of Action: Blocking the Inflammatory Cascade
Erelzi's primary classification is as a tumor necrosis factor (TNF) inhibitor. Its active component, etanercept, works by targeting and blocking TNF, a potent pro-inflammatory protein.
How Erelzi Neutralizes TNF
Etanercept is an engineered dimeric fusion protein that acts as a decoy receptor. It binds to TNF, preventing it from interacting with the body's natural TNF receptors on cell surfaces. By neutralizing TNF, Erelzi disrupts the inflammatory process that causes symptoms and joint damage in various autoimmune diseases.
The role of TNF in inflammatory diseases:
- Triggering inflammation: Overproduction of TNF by the immune system in autoimmune diseases leads to chronic inflammation.
- Joint damage: High levels of TNF contribute to the destruction of joints in conditions like rheumatoid and psoriatic arthritis.
- Skin lesions: In plaque psoriasis, TNF promotes rapid skin cell growth, resulting in characteristic plaques.
Indications and Safety Profile
Erelzi is often recommended for patients with moderate to severe disease who have not responded well to other treatments, such as traditional DMARDs. It is used to treat conditions including rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, plaque psoriasis, and polyarticular juvenile idiopathic arthritis in children aged 2 and above. Like other biologics, Erelzi has safety considerations. Common side effects include injection site reactions, increased risk of common infections, headache, and mild allergic reactions. Serious, potentially life-threatening side effects, highlighted by an FDA boxed warning, include serious infections like TB, fungal infections, and sepsis. TB screening is required before treatment. Other serious risks involve malignancies, worsening or new-onset heart failure, rare nervous system disorders, and hematologic issues. The full prescribing information, including a complete list of indications and safety details, can be found on {Link: accessdata.fda.gov https://www.accessdata.fda.gov/drugsatfda_docs/label/2020/761042s012lbl.pdf}.
Erelzi Compared to Other DMARDs
Erelzi is a modern biologic therapy with a different mode of action compared to older non-biologic DMARDs like methotrexate.
| Feature | Erelzi (etanercept-szzs) | Enbrel (etanercept) | Methotrexate |
|---|---|---|---|
| Drug Class | Biosimilar, TNF inhibitor, Biologic | Reference Biologic, TNF inhibitor | Non-biologic DMARD |
| Mechanism | Decoy receptor binds and neutralizes TNF-alpha, reducing inflammation | Decoy receptor binds and neutralizes TNF-alpha, reducing inflammation | Blocks enzymes involved in purine metabolism, suppressing immune cell function |
| Administration | Subcutaneous injection, typically once or twice weekly | Subcutaneous injection, typically once or twice weekly | Oral tablets or subcutaneous/intramuscular injection |
| Production | Recombinant DNA technology using CHO mammalian cell expression | Recombinant DNA technology using CHO mammalian cell expression | Chemical synthesis |
