Amgen’s subcutaneous TEPEZZA meets primary endpoint in Phase 3 TED trial

Amgen (NASDAQ:AMGN) has announced positive topline results from its Phase 3 clinical trial evaluating a subcutaneous formulation of TEPEZZA (teprotumumab-trbw) for adults with moderate-to-severe active Thyroid Eye Disease (TED).

The trial, which utilized an automated on-body injector for drug delivery, successfully met its primary endpoint.

Data revealed a 76.7% proptosis response rate in patients receiving subcutaneous TEPEZZA, compared to just 19.6% in the placebo group at week 24.

Furthermore, the treatment group showed a mean proptosis reduction of -3.17 mm, significantly outperforming the -0.80 mm reduction observed in the placebo arm (p<0.0001).

The development of a subcutaneous option represents a potential shift in the treatment landscape for TED, a rare and vision-threatening autoimmune condition.

Currently, TEPEZZA is administered via intravenous (IV) infusion, which typically requires patients to spend several hours at an infusion center.

The new on-body injector is designed to provide a more convenient, at-home or clinic-based administration route without sacrificing efficacy.

Safety data from the Phase 3 trial remained consistent with the known profile of IV TEPEZZA.

The most common adverse events reported by at least 10% of participants included muscle spasms, tinnitus, weight decrease, ear discomfort, nausea, and diarrhea.

No new safety signals were identified during the 24-week study period.

Amgen acquired TEPEZZA through its $27.8 billion acquisition of Horizon Therapeutics in 2023.

The drug is a cornerstone of Amgen’s rare disease portfolio, and the introduction of a subcutaneous version is a key component of the company's strategy to defend its market share and expand the addressable patient population.