As reported on BioPharmaDive, Amgen has announced positive Phase 3 results for a subcutaneous version of its thyroid eye disease (TED) therapy Tepezza, suggesting the new formulation performs similarly to the original intravenous infusion. The findings may strengthen Amgen’s position as competition intensifies in a market where convenience and access remain key challenges.
The study evaluated Tepezza delivered through an on-body injector (OBI), rather than the currently approved infusion method. According to the company, the experimental formulation achieved both its primary and a major secondary endpoint over a 24‑week treatment period, demonstrating efficacy comparable to IV-administered Tepezza.
Amgen reported that 77% of patients receiving the OBI formulation met the study’s response criteria, defined by a clinically meaningful reduction in proptosis, or eye bulging. In contrast, approximately one in five patients in the placebo arm showed a similar response. The injectable therapy was also associated with an average reduction in proptosis of just over 3 millimeters, substantially greater than the decrease observed with placebo.
While Amgen did not disclose full trial data, it said the treatment produced statistically significant improvements across additional clinical measures and showed a safety profile aligned with that of the infused drug. Detailed results are expected to be presented at a future scientific meeting.
Tepezza is currently the only FDA-approved therapy for TED, an autoimmune disorder often linked to Graves’ disease that can cause eye protrusion, inflammation, and visual disturbances. The drug became part of Amgen’s portfolio through its $28 billion acquisition of Horizon Therapeutics in 2023 and has generated close to $2 billion in annual sales. However, analysts have noted that revenue growth has flattened in recent quarters.
A subcutaneous option could help broaden use of the drug by reducing reliance on infusion centers, which have been a practical barrier for some patients. Analysts suggest this convenience factor may help reinvigorate growth for the Tepezza franchise.
At the same time, competitors are advancing alternative therapies. Viridian Therapeutics is developing both infusion-based and injectable treatments for TED, including an IV drug that could receive regulatory clearance later this year and a subcutaneous candidate that recently posted mixed Phase 3 results. Investor reaction to Viridian’s data has been cautious, underscoring how closely the market is watching comparative efficacy, safety, dosing frequency, and delivery methods.
As new data emerge, experts say safety outcomes—particularly hearing-related adverse events associated with Tepezza—will be critical in distinguishing options. Still, Amgen’s latest results suggest that offering a more flexible delivery format could play an important role in maintaining its leadership in thyroid eye disease treatment.
