ENBREL (Injectable)

By /

ENBREL (Injectable) — Comprehensive Medical Overview

Introduction

Enbrel (etanercept) is a biologic medication classified as a tumor necrosis factor (TNF) inhibitor, widely used for the treatment of various autoimmune and inflammatory conditions. Administered via subcutaneous injection, Enbrel has transformed the management of diseases such as rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and plaque psoriasis by targeting specific immune pathways responsible for inflammation.

This article offers a thorough review of Enbrel’s indications, mechanism of action, dosing regimens, side effects, warnings, drug interactions, clinical efficacy, and patient guidance.

Uses & Indications

Enbrel is approved for treating the following conditions:

  1. Rheumatoid Arthritis (RA):
    • Reduces signs and symptoms of moderate to severe RA in adults.
    • Slows progression of structural joint damage.
    • Can be used alone or in combination with methotrexate or other DMARDs.
  2. Juvenile Idiopathic Arthritis (JIA):
    • Treatment of moderately to severely active polyarticular JIA in patients aged 2 years and older.
  3. Psoriatic Arthritis (PsA):
    • Reduces signs and symptoms, inhibits progression of structural damage.
  4. Ankylosing Spondylitis (AS):
    • Treatment of active AS to reduce inflammation and improve physical function.
  5. Plaque Psoriasis:
    • Treatment of chronic moderate to severe plaque psoriasis in adults and pediatric patients aged 4 years and older.
  6. Other Indications:
    • Off-label or investigational uses in other autoimmune diseases.

Enbrel plays a pivotal role in improving quality of life and physical function in patients suffering from these chronic inflammatory diseases.

How It Works

Enbrel is a fusion protein combining the extracellular ligand-binding portion of the human tumor necrosis factor receptor 2 (TNFR2) with the Fc portion of human IgG1 antibody.

Mechanism of Action:

  • TNF Inhibition:
    Enbrel binds soluble and transmembrane forms of tumor necrosis factor-alpha (TNF-α), a pro-inflammatory cytokine involved in systemic inflammation. By binding TNF-α, Enbrel prevents it from interacting with its cellular receptors.
  • Reduction of Inflammatory Cascade:
    Blocking TNF-α disrupts the downstream inflammatory processes, decreasing leukocyte activation, cytokine release, and tissue destruction.
  • Modulation of Immune Response:
    This leads to reduced synovial inflammation, joint damage, and skin lesions in psoriasis.

Dosage and Administration

Formulation:

  • Enbrel is available as a prefilled syringe or autoinjector for subcutaneous injection.

Dosage for Adults:

  • Rheumatoid Arthritis, Psoriatic Arthritis, Ankylosing Spondylitis:
    50 mg once weekly or 25 mg twice weekly subcutaneously.
  • Plaque Psoriasis:
    50 mg twice weekly for the first 3 months, then 50 mg once weekly.

Dosage for Pediatric Patients:

  • Juvenile Idiopathic Arthritis:
    • Patients < 63 kg: 0.8 mg/kg weekly (max 50 mg/week).
    • Patients ≥ 63 kg: 50 mg once weekly.
  • Plaque Psoriasis (4 years and older):
    Weight-based dosing ranging from 0.4 mg/kg twice weekly to 50 mg twice weekly depending on body weight.

Administration Instructions:

  • Administer subcutaneously into the thigh, abdomen (avoid 2 inches around the navel), or upper arm.
  • Rotate injection sites to minimize irritation.
  • Use aseptic technique and follow instructions for prefilled syringe or autoinjector.
  • Do not shake the medication vial.
  • Store refrigerated; allow to warm to room temperature before injection.

Side Effects

Common Side Effects:

  • Injection site reactions: redness, itching, swelling, pain.
  • Upper respiratory tract infections: nasopharyngitis, sinusitis.
  • Headache.
  • Rash.
  • Nausea.

Serious Adverse Effects:

  • Serious infections (e.g., tuberculosis, bacterial sepsis, invasive fungal infections).
  • Reactivation of latent tuberculosis or hepatitis B.
  • Malignancies including lymphoma.
  • Demyelinating disorders (e.g., multiple sclerosis).
  • Heart failure exacerbation.
  • Hematologic abnormalities (e.g., pancytopenia).
  • Allergic reactions including anaphylaxis.

Warnings and Precautions

  • Infection Risk:
    Patients should be screened for latent tuberculosis before initiating therapy and monitored regularly.
    Avoid use in patients with active infections.
  • Malignancy:
    Increased risk of lymphoma and other malignancies has been observed; weigh risks versus benefits especially in pediatric patients.
  • Neurologic Events:
    Caution in patients with pre-existing demyelinating diseases.
  • Heart Failure:
    Use cautiously in patients with congestive heart failure; monitor for worsening symptoms.
  • Hematologic Effects:
    Monitor for blood dyscrasias.
  • Immunizations:
    Live vaccines should not be given concurrently with Enbrel.

Drug Interactions

  • Concurrent use with other biologic DMARDs or immunosuppressants increases infection risk.
  • Avoid live vaccines during treatment.
  • Methotrexate may be used concomitantly; monitor for additive immunosuppression.

Clinical Efficacy

  • Enbrel has demonstrated significant improvement in disease activity scores, physical function, and quality of life measures in RA, PsA, AS, and psoriasis.
  • Radiographic studies show slowed progression of joint damage in RA and PsA.
  • Clinical trials have shown sustained efficacy and safety over long-term use.

Patient Counseling

  • Explain proper injection technique and importance of adherence.
  • Inform about potential side effects and signs of infection or allergic reactions.
  • Emphasize need for regular monitoring and follow-up appointments.
  • Discuss lifestyle modifications to reduce infection risk.
  • Advise patients to report any unusual symptoms promptly.

FAQs

Q1: How quickly does Enbrel start to work?
A: Some patients notice improvement within 1-2 weeks, but full effect may take 3 months.

Q2: Can I take Enbrel with other arthritis medications?
A: Yes, but only under doctor supervision; combination with other biologics is generally avoided.

Q3: What should I do if I miss a dose?
A: Take as soon as possible unless it is near the next scheduled dose; do not double dose.

Q4: Is Enbrel safe during pregnancy?
A: Risks and benefits should be discussed with your healthcare provider; limited data available.

Q5: Can Enbrel cause cancer?
A: There is a potential increased risk, particularly lymphoma; discuss concerns with your doctor.

Summary

Enbrel (etanercept) is a cornerstone biologic therapy for autoimmune inflammatory diseases, offering targeted inhibition of TNF-alpha to reduce inflammation and improve patient outcomes. Proper patient selection, screening, and monitoring optimize therapeutic success while minimizing risks. Enbrel’s well-characterized profile supports its use across a broad spectrum of chronic inflammatory disorders.

References

  1. Enbrel [Prescribing Information]. Amgen Inc.; 2023. https://www.enbrel.com
  2. Smolen JS, et al. Rheumatoid arthritis. Lancet. 2016;388(10055):2023-2038.
  3. National Psoriasis Foundation. TNF inhibitors for psoriasis. https://www.psoriasis.org
  4. Singh JA, et al. 2015 American College of Rheumatology guideline for the treatment of rheumatoid arthritis. Arthritis Rheumatol. 2016;68(1):1-26.
  5. Mayo Clinic. Enbrel (etanercept). https://www.mayoclinic.org/drugs-supplements/etanercept-subcutaneous-route/description/drg-20062422

Table of Contents

→ Index
Scroll to Top