Erelzi: Biosimilar to Enbrel Approved for Rheumatoid Arthritis

Also Approved for Some Other Types of Inflammatory Arthritis

Injection into the thigh
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Erelzi (etanercept-szzs), a biosimilar to Enbrel (etanercept), was approved by the FDA on August 30, 2016 to treat the same indications for which Enbrel was originally approved. Enbrel was the first biologic drug approved for rheumatoid arthritis and certain other inflammatory types of arthritis in 1998.

A biosimilar is a biological product which is highly similar to the original FDA-approved biological product (known as the reference product), and shows no clinically meaningful differences from the reference product with regard to safety and effectiveness.

There may be minor differences in clinically inactive ingredients. The inactive ingredients in Erelzi include sodium citrate, sucrose, sodium chloride, lysine, and citric acid.

Erelzi is manufactured by Sandoz, the company which had the first biosimilar approved by the FDA, (Zarxio [filgrastim-sndz])—a biosimilar to the white blood cell booster Neupogen (filgrastim).  The first biosimilar for inflammatory types of arthritis was Inflectra (infliximab-dyyb) which is the biosimilar to Remicade (infliximab). The approval of Erelzi came on the heels of a 20-0 unanimous recommendation by the FDA Arthritis Advisory Committee to approve the drug for all indications of its reference drug.

Indications for Erelzi

Erelzi is a tumor necrosis factor (TNF) blocker which is indicated for:

    Recommended Dosage and Administration

    Erelzi is administered by subcutaneous injection. It is available as a 25 mg/0.5mL and 50 mg/mL solution in a single dose prefilled syringe. Erelzi also comes in a 50mg/mL solution in a prefilled Sensoready pen.

    The recommended dose for people with adult rheumatoid arthritis or psoriatic arthritis is 50 mg once weekly, either with or without methotrexate.

    The recommended dose for people with ankylosing spondylitis is 50 mg once weekly. For adult plaque psoriasis, the recommended dose of Erelzi is 50 mg twice weekly for 3 months followed by 50 mg weekly. The dose for juvenile idiopathic arthritis is based on weight—for children who weigh more than 63 kg, the dose is 0.8mg/kg weekly with a maximum dose of 50 mg pr week.

    Side Effects and Adverse Reactions

    As with any drug, there are side effects and adverse events associated with Erelzi. The most common adverse events associated with etanercept are infections and and injection site reactions. Based on clinical studies and postmarketing experience, the most serious adverse events associated with etanercept included infections, neurologic problems, congestive heart failure, and hematologic events (i.e., blood disorders).


    Erelzi should not be given to anyone with sepsis.

    Warnings and Precautions

    There are important warnings and precautions associated with the use of Erelzi which should not be ignored:

    • Erelzi should not be started during an active infection. If an active infection develops during treatment, Erelzi may need to be stopped.
    • In people who travel to or live in regions where mycoses are endemic, if severe systemic illness develops while treated with Erelzi, anti-fungal therapy should be considered.
    • Demyelinating disease may develop while treated with Erelzi.
    • Lymphoma cases have occurred in people treated with TNF blockers.
    • Congestive heart failure may occur, either new onset or as a worsening condition.
    • People with symptoms of pancytopenia or aplastic anemia should seek medical attention and consider stopping Erelzi.
    • People with a history of of Hepatitis B should be monitored for reactivation while treated with Erelzi and several months after.
    • Anaphylaxis or severe allergic reactions can occur while treated with Erelzi.
    • Lupus-like syndrome or autoimmune hepatitis may develop. If either occurs, Erelzi should be stopped.

    Drug Interactions

    There have been no studies conducted regarding specific drug interactions with etanercept. From other studies it was determined that people treated with etanercept should AVOID:

    The Bottom Line

    The stated goal for developing biosimilars is to offer patients and doctors more treatment options at an affordable cost, considerably lower than the cost of the reference drugs. While that sounds good on first read, there are clearly concerns that have come to light. The enormous concern is still whether biosimilars are "equivalent" to their reference drugs. Biosimilars have been called "highly similar" but is that the same as equivalent? Has that question been satisfactorily answered? The dance around the terminology leaves many still feeling uneasy.

    As of 2016, the price point has not been announced either. So, we must wait to see exactly how "more affordable" translates into real dollars. You might think to check on how Inflectra, the Remicade biosimilar which was approved in April 2016, has performed in terms of cost and effectiveness. As of 2016, it hasn't launched in the United States.

    To add to confusion, there are court cases about patent issues. While biosimilars may become a real option in the future, for now it seems fraught with problems. Talk to your doctor about whether or not it's the right choice for you.


    Erelzi. Full Prescribing Information and Medication Guide. Sandoz, Inc. Revised 08/2016.

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