Biologic Disease-Modifying Drugs for Thyroid Eye Disease

Thyroid eye disease (TED) is a complex, rare condition that affects the tissues in and around the eyes. TED can result in significant disfigurement and vision loss, leading to decreased quality of life, mental health, and social isolation. Everyone is different, and symptoms of TED vary from person to person. However, symptoms are progressive and, when left untreated, may lead to significant damage and loss of vision.1

Steroids are often used to treat TED during the acute (active) phase. Steroids are drugs that rapidly decrease inflammation, which helps decrease the symptoms of TED. However, long-term steroid use has complications. Plus, when steroid therapy is stopped, many people with TED continue to have symptoms.1

New and more efficient treatment strategies are being developed with more knowledge on how TED affects the body. Biologic disease-modifying drugs (DMDs) are used to help treat the symptoms of TED. Monoclonal antibody drugs are a type of biologic DMDs.1

What are disease-modifying drugs?

DMDS are drugs used to treat inflammatory or immune diseases. There are 2 kinds of DMDs: traditional (also called synthetic) and biologics. Biologic DMDs are used in the treatment of TED.2

Biologics are drugs made from living cells. These cells can come from parts of the blood, proteins, viruses, or tissue. The process of making biologics turns these cells into drugs that can prevent, treat, and cure some diseases. Drugs similar in structure to known biologic drugs are called biosimilars.

How do they work?

Biologic DMDs are designed to target specific parts of the immune system that affect inflammation. These drugs interfere with cytokine production or function. Cytokines are proteins made by certain cells in the immune system that help to regulate immunity and inflammation.2

Biologics also work by:2

  • Blocking signals for certain cells involved in the inflammation process
  • Decreasing the number of some cells or blocking activators of cells involved in inflammation

Examples of biologic disease-modifying drugs used for TED

As of September 2021, Tepezza® (teprotumumab-trbw) is the only biologic DMD approved by the U.S. Food and Drug Administration (FDA) to treat TED. Tepezza is a monoclonal antibody. Monoclonal antibodies work by acting like proteins made by your immune system.3

Tepezza blocks a receptor in the body that can be “turned on” when there is too much thyroid hormone in the blood. This receptor is called insulin-like growth factor-1 (IGF-1R). Turning on IGF-1R leads to growth of muscle, fat, and connective tissue cells. Too much growth of these cells causes the symptoms of thyroid eye disease.4

Tepezza is classified as an IGF-1R inhibitor. By blocking IGF-1R, Tepezza decreases the muscle, fat, and connective tissue swelling that is common in TED. This improves symptoms of TED, including:5

What are the possible side effects?

Side effects can vary depending on the specific drug you are taking. Because Tepezza is the only approved biologic DMD used to treat TED as of 2021, the most common side effects of Tepezza include:3,5

  • Infusion reactions
  • Worsening of existing inflammatory bowel disease (IBD)
  • High blood sugar (hyperglycemia)

Other side effects include:3,5

  • Muscle spasms
  • Nausea
  • Hair loss (alopecia)
  • Diarrhea
  • Fatigue
  • Hearing problems
  • Changes in taste
  • Headache
  • Dry skin

These are not all the possible side effects of Tepezza. Talk to your doctor about what to expect when taking Tepezza. You also should call your doctor if you have any changes that concern you when taking Tepezza.3,5

Things to know

Biologic DMDs are not right for everyone. If you have inflammatory bowel disease (IBD), you should not take Tepezza.3,5

Infusion reactions can happen during or within 24 hours of your Tepezza dose. Tell your doctor or nurse right away if you have any of these symptoms:3,5

  • Fast heartbeat
  • Increased blood pressure
  • Feeling hot
  • Redness of your face
  • Trouble breathing
  • Headache
  • Muscle pain

If you have a reaction, your doctor or nurse will slow or stop Tepezza. If your reaction is severe, you may not be able to take Tepezza.5

Talk to your doctor or TED specialist about what treatment is right for you. Knowing the risks and benefits of therapies helps you in your treatment journey with TED.

Before beginning treatment for TED, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you take. This includes over-the-counter drugs.

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Written by: Katie Murphy | Last reviewed: October 2021