Tepezza is currently the only FDA‑approved therapy for TED and has been used in clinical practice since 2020. According to Amgen, more than 25,000 patients worldwide have been treated with IV Tepezza to date. The new trial aimed to determine whether subcutaneous delivery could maintain the therapy’s clinical benefits while simplifying administration.

Key efficacy findings

The randomized, double-masked, placebo-controlled, multicenter study met its primary endpoint. During the 24‑week placebo-controlled period, approximately 77% of patients receiving subcutaneous Tepezza achieved a proptosis response, compared with about 20% in the placebo group, a difference that was both statistically significant and clinically meaningful.

A key secondary endpoint (mean change in proptosis) also favored active treatment. At week 24, patients treated with the subcutaneous formulation experienced an average reduction in eye bulging of just over 3 mm, versus less than 1 mm with placebo.

In addition, the trial demonstrated significant improvements across multiple secondary measures, including overall response rates, reductions in disease activity scores, and improvements in diplopia. Patients also reported meaningful gains on the appearance-related subscale of the Graves’ Ophthalmopathy Quality of Life (GO-QoL) assessment. While improvements in the GO-QoL visual functioning subscale did not reach statistical significance, the data showed a numerical trend in favor of Tepezza.

Full trial results are expected to be presented at a future medical conference.

Safety profile

Overall safety findings were consistent with the known profile of IV Tepezza. Mild-to-moderate injection site reactions were reported with subcutaneous administration but did not lead to treatment discontinuation. The most frequently observed adverse events included muscle spasms, tinnitus, weight loss, ear discomfort, nausea, and diarrhea.

Jay Bradner, MD, executive vice president of research and development at Amgen, said the results support expanding how Tepezza is delivered. He noted that subcutaneous administration may help increase accessibility while preserving the therapy’s established efficacy.

Trial design and patient population

Participants in the phase 3 trial were adults with moderate-to-severe active TED diagnosed within 15 months. Eligible patients had clinically significant proptosis relative to their pre‑TED baseline. Treatment consisted of 12 injections administered every two weeks via an on‑body injector. Notably, individuals with baseline hearing impairment were permitted to enroll, reflecting real-world TED populations.

Amgen also reported completion of a separate phase 3b/4 post-marketing study of IV Tepezza, conducted to meet an FDA requirement. That descriptive study evaluated the safety and tolerability of different infusion durations and the potential need for retreatment. The safety findings aligned with the established risk profile, and results will be submitted to regulators and shared at an upcoming congress.

About thyroid eye disease and Tepezza

TED is a rare autoimmune condition often associated with Graves’ disease but considered a distinct disorder. It is driven by autoantibodies that activate insulin-like growth factor‑1 receptor signaling in tissues behind the eye, leading to inflammation, tissue expansion, and symptoms such as eye bulging, double vision, pain, and swelling. In severe cases, the disease can threaten vision and significantly impair quality of life.

Tepezza targets the underlying disease mechanism and is approved for the treatment of TED regardless of disease activity or duration. Clinical trials and real‑world use have consistently shown its ability to reduce proptosis and diplopia, two hallmark features of the condition. If approved, a subcutaneous formulation could represent an important step forward in how this therapy is delivered to patients.