Amgen announced positive Phase 3 results showing subcutaneous TEPEZZA achieved a 76.7% proptosis response at Week 24 in moderate-to-severe Thyroid Eye Disease, with safety consistent with IV formulation.
Written By: Vikas Londhe, Chief Editor
Amgen reported positive topline results from a Phase 3 trial evaluating subcutaneous TEPEZZA delivered via an on-body injector in patients with moderate-to-severe active Thyroid Eye Disease (TED). The investigational subcutaneous formulation demonstrated efficacy comparable to intravenous TEPEZZA, the first approved therapy for TED, which has been used in more than 25,000 patients globally.
The randomized, double-masked, placebo-controlled Phase 3 study (NCT06248619) met its primary endpoint, showing a statistically significant proptosis response rate of 76.7% with TEPEZZA OBI compared with 19.6% for placebo at Week 24 (p<0.0001). The treatment also achieved a key secondary endpoint, with mean proptosis reduction of −3.17 mm versus −0.80 mm for placebo (p<0.0001).
Additional secondary endpoints also showed clinically meaningful improvements, including overall responder rate, reduction in Clinical Activity Score, diplopia response measures, and improvement in Graves’ Ophthalmopathy Quality of Life appearance scores. A numerical trend favored TEPEZZA in visual functioning scores, although this endpoint did not reach statistical significance. Full data will be presented at a future medical congress.
According to Jay Bradner, executive vice president of Research and Development at Amgen, the findings support the established efficacy of TEPEZZA while introducing a more convenient subcutaneous delivery option that may expand patient access. Investigators also noted that providing an alternative to intravenous infusion could improve treatment accessibility for patients with TED while maintaining comparable efficacy.
Safety findings were consistent with the known profile of intravenous TEPEZZA. Mild-to-moderate injection-site reactions occurred with subcutaneous administration but did not lead to treatment interruption or discontinuation. The most common adverse events occurring in at least 10% of patients included muscle spasms, tinnitus, weight decrease, ear discomfort, nausea, and diarrhea.
The multicenter trial enrolled patients with moderate-to-severe active TED diagnosed within 15 months. Participants received TEPEZZA or placebo every two weeks for 12 injections. The primary endpoint assessed the proportion of patients achieving at least a 2-mm reduction in proptosis without worsening in the fellow eye at Week 24.
Amgen also reported completion of a separate Phase 3b/4 post-marketing requirement study evaluating different treatment durations of intravenous TEPEZZA. The descriptive analysis showed a safety profile consistent with previous experience, and results will be submitted to regulatory authorities.
Thyroid Eye Disease is a rare autoimmune condition that can cause eye bulging, double vision, pain, redness, and swelling, and may threaten vision. The disease is associated with autoantibody activation of insulin-like growth factor-1 receptor signaling in orbital tissues. TEPEZZA targets this pathway and remains the only approved therapy specifically indicated for TED.
Reference
Amgen Announces Positive Topline Phase 3 Results for Subcutaneous Tepezza® in Adults Living With Moderate-To-Severe Active Thyroid Eye Disease, 06 April 2026, AMGEN ANNOUNCES POSITIVE TOPLINE PHASE 3 RESULTS FOR SUBCUTANEOUS TEPEZZA® IN ADULTS LIVING WITH MODERATE-TO-SEVERE ACTIVE THYROID EYE DISEASE | Amgen Inc.
A Trial to Investigate Teprotumumab Subcutaneous Administration Compared with Placebo in Male and Female Adult Participants with Moderate-to-severe Active Thyroid Eye Disease, ClinicalTrials.gov ID NCT06248619, https://clinicaltrials.gov/study/NCT06248619