Injected Tepezza Works as Well as IV Version in Phase 3 Trial

Written by Ted Samson

Posted on May 18, 2026

Feel better informed on TED and get real support from your community.

A new injected version of teprotumumab-trbw (Tepezza) may offer people living with thyroid eye disease (TED) a more convenient treatment option for proptosis (eye bulging). Trial results suggest it may be effective.

In a phase 3 clinical trial, 77 percent of participants with moderate to severe active TED had much less eye bulging after 24 weeks of treatment. In comparison, about 20 percent of people who received a placebo, or inactive treatment, had the same result.

Currently, Tepezza is available only as an intravenous (IV) infusion given at a clinic or infusion center. Intravenous means the medicine goes into a vein. Treatment involves eight infusions over about six months. Each infusion lasts 60 to 90 minutes.

The new version is designed to be delivered through a wearable injector, which could make treatment easier and more accessible for some people with TED.

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What Is Tepezza and How Does It Work?

Tepezza was first approved by the U.S. Food and Drug Administration (FDA) in 2020. It is currently the only approved medication specifically for TED.

Tepezza targets a protein called insulin-like growth factor-1 receptor (IGF-1R), which researchers believe plays a role in TED.

By blocking IGF-1R activity, Tepezza may help reduce swelling and pressure behind the eyes, leading to improvements in symptoms like eye bulging and double vision.

Trial Results Showed Meaningful Improvements

The phase 3 study included adults with active moderate to severe TED. Participants received either Tepezza through an on-body injector or a placebo every two weeks for 24 weeks.

Researchers measured proptosis response. This means eye bulging improved by at least 2 millimeters without getting worse in the other eye.

The injected version met the study’s main goal: 76.7 percent of people who received it had this response, compared with 19.6 percent of those who received a placebo.

The treatment reduced eye bulging by more than 3 millimeters on average. Researchers also reported improvements in several other areas, including:

Double vision
Disease activity scores
Overall response rates
Quality-of-life scores related to appearance

Potential Side Effects

Like all treatments, Tepezza may cause side effects. In the trial, some people had mild to moderate reactions where the medicine was injected. However, these reactions did not cause anyone to stop treatment.

The most common side effects reported in the trial included:

Muscle spasms
Tinnitus (ringing in the ears)
Ear discomfort
Nausea
Diarrhea
Weight loss

Tepezza already has warnings for rare but serious side effects, including:

Hearing problems, including possible permanent hearing loss
Hyperglycemia (high blood sugar)
Infusion reactions
Worsening inflammatory bowel disease

What These Trial Results Mean for People With TED

Eye symptoms icon For people living with TED, a subcutaneous version of Tepezza could make treatment easier. Subcutaneous means the medicine is given under the skin instead of through a vein.

This option could help reduce some challenges tied to IV infusions, such as long clinic visits and travel to infusion centers. A wearable injector may also help people who have trouble scheduling or getting to regular infusion appointments.

In its announcement of the trial results, Amgen said it plans to submit the data to regulators. Before this version can become available, regulators need to review the study results. They will decide whether the new delivery method is safe and works well.

If your TED treatment plan is not controlling symptoms like eye bulging, pain, swelling, or double vision, talk with your healthcare provider. They can discuss available treatment options and whether new therapies or clinical trials could be right for you.