Thousand Oaks, California, USA, April 6, 2026
Phase 3 Success Expands TEPEZZA Treatment Options
In a major advancement for rare autoimmune disease treatment, Amgen has announced positive Phase 3 topline results for its subcutaneous formulation of TEPEZZA® (teprotumumab-trbw) in adults with moderate-to-severe active Thyroid Eye Disease (TED). The study successfully met both primary and key secondary endpoints, demonstrating a 77% proptosis response rate compared to 19.6% in the placebo group (p<0.0001), marking a highly statistically significant and clinically meaningful outcome.
Notably, the subcutaneous delivery method achieved comparable efficacy to the intravenous (IV) formulation, which remains the first and only approved therapy for TED. The findings highlight the potential to expand patient access through a more convenient administration route, addressing a critical need for improved treatment adherence and patient experience in this vision-threatening autoimmune condition.
Clinically Meaningful Outcomes and Patient Benefits
The trial demonstrated a mean proptosis reduction of -3.17 mm, significantly greater than the placebo group’s -0.80 mm, confirming a substantial improvement in one of the most debilitating symptoms of TED—eye bulging. In addition to the primary endpoint, TEPEZZA showed significant improvements across multiple secondary endpoints, including overall responder rates, Clinical Activity Score (CAS), diplopia response, and quality of life measures. These results underscore the therapy’s ability to deliver comprehensive clinical benefits, improving both functional vision outcomes and patient-reported quality of life.
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TED is a serious and progressive autoimmune disorder, often associated with Graves’ disease, and can lead to double vision, pain, inflammation, and potential vision loss. By targeting the insulin-like growth factor-1 receptor (IGF-1R) pathway, TEPEZZA directly addresses the underlying disease mechanism, offering a disease-modifying approach rather than symptomatic relief.
Favorable Safety Profile and Improved Administration
Safety data from the Phase 3 trial were consistent with the established safety profile of intravenous TEPEZZA, with no new safety signals identified. The most common adverse events included muscle spasms, nausea, tinnitus, weight decrease, and mild-to-moderate injection site reactions, which did not lead to treatment discontinuation. Importantly, the introduction of an on-body injector (OBI) for subcutaneous administration allows patients to receive treatment every two weeks without the need for intravenous infusion, significantly enhancing treatment convenience and accessibility.
This innovation is expected to improve patient compliance and healthcare system efficiency, particularly for individuals who face challenges with frequent hospital visits. The study enrolled patients with moderate-to-severe TED diagnosed within 15 months, ensuring robust evaluation in a clinically relevant population.
Transforming the Future of TED Treatment
The success of the subcutaneous TEPEZZA formulation represents a broader trend toward patient-centric drug delivery innovations in the biopharmaceutical industry. With more than 25,000 patients already treated worldwide using IV TEPEZZA, the introduction of a subcutaneous alternative has the potential to significantly expand its reach and impact. This development reinforces Amgen’s commitment to advancing innovative therapies that improve both clinical outcomes and patient experience.
As regulatory submissions progress and additional data are presented at upcoming medical congresses, the subcutaneous formulation could become a new standard of care for Thyroid Eye Disease, offering patients a more accessible, effective, and convenient treatment option. This milestone not only strengthens TEPEZZA’s position as a best-in-class therapy but also highlights the ongoing evolution of precision biologics in autoimmune and rare disease management.
Source: Amgen press release
