Amgen has reported positive topline results from a phase 3 trial evaluating a subcutaneous formulation of teprotumumab (TEPEZZA) in patients with moderate-to-severe active thyroid eye disease (TED), potentially expanding how the therapy is delivered in clinical practice.
The study met both its primary and key secondary endpoints, with 77% of patients receiving subcutaneous TEPEZZA achieving a proptosis response at 24 weeks, compared with 19.6% in the placebo arm. Mean proptosis reduction reached −3.17 mm at week 24, a clinically meaningful improvement and a magnitude consistent with outcomes previously reported for the intravenous (IV) formulation.
TEPEZZA remains the first and only approved therapy for TED, and the subcutaneous version – delivered via an on-body injector every two weeks – aims to offer comparable efficacy with greater convenience. According to Amgen, more than 25,000 patients worldwide have already been treated with the IV formulation.
Beyond proptosis, the trial demonstrated statistically significant improvements across multiple secondary endpoints, including overall responder rates, Clinical Activity Score (CAS), diplopia outcomes, and patient-reported quality of life measures related to appearance. While improvements in visual functioning scores did not reach statistical significance, a favorable numerical trend was observed.
Safety findings were consistent with the known profile of IV TEPEZZA. The most common adverse events included muscle spasms, tinnitus, weight loss, gastrointestinal symptoms, and ear discomfort. Mild-to-moderate injection site reactions were reported with subcutaneous administration but did not lead to treatment interruption or discontinuation.
TED is a progressive autoimmune condition, often associated with Graves’ disease, characterized by orbital inflammation and tissue expansion. Clinical manifestations – including proptosis, diplopia, and ocular discomfort – can significantly impact both vision and quality of life.
The move toward subcutaneous delivery reflects a broader trend in biologic therapies, aiming to reduce treatment burden and improve accessibility. Investigators highlighted the potential for this formulation to offer a more flexible treatment experience while maintaining efficacy comparable to IV administration.
Full data from the trial are expected to be presented at an upcoming medical congress. Meanwhile, Amgen also noted completion of a separate Phase 3b/4 study evaluating different IV treatment durations, with results to be submitted to regulators.
If confirmed in further analyses and regulatory review, subcutaneous TEPEZZA could represent a meaningful evolution in the management of TED – particularly for patients and clinics seeking alternatives to infusion-based care.
Source: PR Newswire.
