Subcutaneous TEPEZZA Hits the Mark in Phase 3 Trial for Thyroid Eye Disease

Amgen has announced positive results from a Phase 3 trial testing a new way to deliver TEPEZZA, the only FDA-approved medicine for thyroid eye disease, an autoimmune condition closely linked to Graves' disease. Thyroid eye disease, also called Graves' ophthalmopathy, happens when the same autoantibodies that overstimulate the thyroid gland also attack tissue behind the eyes, causing bulging, double vision, pain, redness, and in severe cases, threats to eyesight. TEPEZZA, given as an intravenous infusion since its 2020 approval, has already treated more than twenty-five thousand patients, but the IV format requires infusion visits that can be inconvenient for many people managing a chronic condition.

The new trial tested a subcutaneous version of TEPEZZA delivered through an on-body injector, meaning patients could potentially receive treatment without a clinic infusion. In the 24-week, placebo-controlled portion of the study, more than three-quarters of patients receiving the subcutaneous version saw meaningful improvement in proptosis, the medical term for eye bulging, compared to about one in five on placebo. The average reduction in proptosis was just over three millimeters, a difference Amgen and outside ophthalmologists described as both statistically significant and clinically meaningful for patients living with this condition.

Beyond the primary measure, the trial also showed improvements in double vision, in the percentage of patients reaching low disease activity scores, and in quality of life measures related to how patients felt about their appearance. Safety results were largely consistent with what has already been seen with the IV version of the drug, though some patients experienced mild to moderate reactions at the injection site. These reactions did not lead patients to stop treatment. Known risks of TEPEZZA, including hearing changes, elevated blood sugar, and flare ups of inflammatory bowel disease, still apply and should be discussed with a treating physician.

For patients with thyroid eye disease, a subcutaneous option could mean fewer hours spent in infusion chairs and more flexibility in how and where treatment happens, without giving up the effectiveness that made TEPEZZA the standard of care. Full results are expected to be presented at an upcoming medical meeting, and Amgen has not yet specified a timeline for seeking regulatory approval of the subcutaneous formulation. Patients currently on or considering TEPEZZA should talk with their endocrinologist or ophthalmologist about whether to wait for the new delivery option or proceed with the infusion version already available.