Tepezza OBI Achieves Proptosis Reduction in Thyroid Eye Disease in Phase 3 Trial

On April 6, 2026, Amgen announced positive topline results from a phase 3 trial of teprotumumab-trbw (Tepezza), administered via an on-body injector (OBI), for the treatment of moderate-to-severe thyroid eye disease (TED).1

Tepezza was first approved by the US Food and Drug Administration in 2020 and is the first and only approved medicine for TED. It is designed to reduce proptosis and double vision – 2 hallmark symptoms of TED – and has demonstrated its efficacy across several global clinical studies. Additionally, the drug’s safety and efficacy are well-established via 6 years of real-world experience in >25,000 patients.1,2

“These results extend and support the best-in-class efficacy of Tepezza for people living with thyroid eye disease, now with subcutaneous administration delivering IV-level efficacy,” Jay Bradner, MD, executive vice president of research and development at Amgen, said in a statement. “With a well-understood mechanism and established impact in the clinic, we can evolve how the medicine is delivered to potentially reach even more patients through a more convenient subcutaneous option.”1

The present study was a randomized, double-masked, placebo-controlled, parallel-group, multicenter trial, aiming to evaluate the efficacy and safety of subcutaneously administered Tepezza in patients with active TED compared to placebo. Investigators included a primary endpoint of proptosis responder rate, measured as the percentage of participants with a ≥2mm reduction from baseline in the study eye without deterioration of proptosis in the fellow eye by week 24.1

To be eligible for inclusion, patients had to have a diagnosis of moderate-to-severe active TED within 15 months and proptosis of ≥3 mm from baseline prior to TED diagnosis, among other criteria. Patients were administered Tepezza or placebo via an OBI every 2 weeks, totaling to 12 injections.1

Ultimately, the trial met its primary endpoint, reflecting a statistically significant and clinically meaningful 77% proptosis response rate (76.7% Tepezza OBI vs 19.6% placebo; P <.0001). Additionally, the mean proptosis reduction was -3.17 mm by week 24 (-3.17mm Tepezza OBI vs -0.8 mm placebo; P <.0001).1

Investigators also saw significant improvements in overall responder rate, the percentage of patients achieving a Clinical Activity Score (CAS) of 0 or 1, change in diplopia as ordinal response categories, diplopia response rate, and mean change from baseline in week 24 in the Graves’ Ophthalmology Quality of Life (GO-QoL) appearance subscale, among other secondary endpoints. Despite not achieving statistical significance, the team saw a numerical trend in the mean change in baseline at week 24 in the GO-QoL visual functioning subscale favoring Tepezza OBI.1

“Thyroid eye disease can be a profoundly debilitating condition, affecting not only vision but also daily functioning with symptoms like double vision and eye bulging,” Madhura Tamhankar, MD, professor of ophthalmology and neurology at the Scheie Eye Institute, University of Pennsylvania, said in a statement. “Expanding administration options through subcutaneous delivery opens the possibility of a more accessible experience for patients with thyroid eye disease and is critical to serving diverse patient needs. The potential to achieve comparable efficacy to IV makes this advancement compelling.”1

References

1. Amgen. Amgen Announces Positive Topline Phase 3 Results for Subcutaneous Tepezza in Adults Living With Moderate-to-Severe Active Thyroid Eye Disease. April 6, 2026. Accessed April 6, 2026. https://investors.amgen.com/news-releases/news-release-details/amgen-announces-positive-topline-phase-3-results-subcutaneous

2. US Food and Drug Administration. FDA approves first treatment for thyroid eye disease. PRNewswire. January 21, 2020. Accessed April 6, 2026. https://www.prnewswire.com/news-releases/fda-approves-first-treatment-for-thyroid-eye-disease-300990621.html