Erelzi® - Biosimilar for Enbrel (etanercept)

Written by: Juliana Swaren | Last reviewed: March 2022 | Last updated: April 2022

Erelzi (etanercept-szzs) is an engineered biologic medication that is “biosimilar” to Enbrel (etanercept). It was approved for use in patients with moderate to severe rheumatoid arthritis. Biosimilar medications are approved based on the similarity of their action to approved medications.1

Patients taking Erelzi in clinical trials experienced an improvement in disease progression and quality of life according to clinical assessments and radiological studies. This medication can be used either alone or with methotrexate.2

Erelzi is also approved for use in other autoimmune diseases, including polyarticular juvenile idiopathic arthritis, psoriatic arthritis, ankylosing spondylitis, and plaque psoriasis.2

Erelzi is not available in generic forms; Erelzi is not currently available in the United States.

What are the ingredients in Erelzi?

The active ingredient in Erelzi is etanercept-szzs.3

How does Erelzi work?

Erelzi is one of several monoclonal antibodies used to treat RA. Our bodies naturally produce antibodies, which are immune factors that act against bacteria, viruses, and other foreign organisms that invade and pose a threat to our health. Drug makers have engineered a variety of antibodies to target the mechanisms that cause certain diseases, including RA.

Like Enbrel, Erelzi is a tumor necrosis factor (TNF) blocker. TNF is an important immune system signaling factor (called a cytokine) that plays a key role in swelling and inflammation. It is found in higher levels in the synovial fluid in the joints of patients with RA, and it is connected to inflammation as well as bone and cartilage damage.4

Erelzi blocks the action of tumor necrosis factor by binding to the molecule and preventing it from attaching to cell-surface proteins that are important in its activation. Blocking TNF helps tamp down the damage caused by the dysfunction of the immune system that is characteristic of RA.2

What are the possible side effects of Erelzi?

Common side effects with Erelzi include2,3:

  • Redness, itching, pain, or swelling at the site of injection
  • Upper respiratory infections like colds and sinus problems
  • Headache

In some patients, Erelzi can cause more harmful side effects. Patients who take Erelzi are at increased risk for serious infections, including tuberculosis, invasive fungal infections, viral infections, bacterial infections, and other opportunistic infections (infection caused by a microorganism that does not normally cause infection in humans, typically due to an abnormally functioning immune system).3 For more information on adverse effects such as infections and malignancy, see the FDA black box warning for Erelzi.

Children, adolescents, and some adults taking TNF blockers like Erelzi and Enbrel are also at slightly higher risk for lymphoma and other cancers. Other rare but serious side effects include Hepatitis B or TB reactivation, nerve diseases like multiple sclerosis, certain blood disorders, heart failure, and psoriasis.3

This is not an exhaustive list of all potential side effects of Erelzi. For more information, consult your doctor or healthcare provider. If you notice any new or worsening side effects, contact your doctor or healthcare provider immediately.

Things to note about Erelzi

Before taking Erelzi, tell your doctor if you3:

  • Have a current infection or are prone to recurring infections, including open cuts
  • Have HIV, diabetes, or a weakened immune system
  • Have tested positive for TB or have been in close contact with someone who has TB
  • Live in areas of the US known for fungal infections, including the Ohio and Mississippi Valley and the southwest
  • Have or have had Hepatitis B
  • Have any nervous system problems like multiple sclerosis or Guillain-Barré syndrome
  • Have or have had heart problems
  • Are scheduled to have surgery
  • Are scheduled to receive a vaccine
  • Are pregnant or plan to become pregnant or are breastfeeding

With Erelzi, there is an increased risk for serious infection. This is because it can decrease the ability of the immune system to fight infections. If an infection develops while you are taking this medication, or if you have a severe allergic reaction, contact your doctor immediately. You will need to stop the medication until the infection resolves.2

Patients taking this medication should not receive live vaccines. Patients with heart disease should not take Erelzi, because it increases your risk of heart failure. Tell your doctor about any medications or supplements you are taking while on Erelzi, because you have a higher chance of getting infections if you are taking it with certain other medications. It is important for doctors to test for TB before you take Erelzi and to monitor for it while you are on the medication.2

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