Amgen has announced positive topline results from a phase-III trial of TEPEZZA (teprotumumab-trbw) administered by subcutaneous injection via an On-Body Injector (OBI) in participants with moderate-to-severe active Thyroid Eye Disease (TED). TEPEZZA OBI provides comparable efficacy to, and builds upon the success of, intravenous (IV) TEPEZZA, the first and only medicine approved for the treatment of TED, which has now treated more than 25,000 patients worldwide.

The phase-III TEPEZZA OBI trial met its primary endpoint in moderate-to-severe active TED, showing a statistically significant and clinically meaningful 77 percent proptosis response rate during the 24-week placebo-controlled period (76.7 percent TEPEZZA OBI vs. 19.6 percent placebo [p<0.0001]). Importantly, the mean proptosis reduction, a key secondary endpoint, was -3.17 mm at week 24 (-3.17 mm TEPEZZA OBI vs. -0.80 mm placebo; p<0.0001).

"These results extend and support the best-in-class efficacy of TEPEZZA for people living with Thyroid Eye Disease, now with subcutaneous administration delivering IV-level efficacy. With a well-understood mechanism and established impact in the clinic, we can evolve how the medicine is delivered to potentially reach even more patients through a more convenient subcutaneous option," said Jay Bradner, M.D., Executive Vice President–Research and Development, Amgen.

The trial also showed statistically significant and clinically meaningful improvements across the following additional secondary endpoints: overall responder rate; percentage of patients achieving a Clinical Activity Score (CAS) of 0 or 1; change in diplopia as ordinal response categories; diplopia response rate; complete diplopia responder rate; and mean change from baseline in week 24 in the Graves' Ophthalmopathy Quality of Life (GO-QoL) appearance subscale. Although not statistically significant, there was a numerical trend favouring TEPEZZA OBI in the mean change in baseline at week 24 in the GO-QoL visual functioning subscale.

The overall safety results were generally consistent with the known safety profile of TEPEZZA IV. Mild-to-moderate injection site reactions were observed with subcutaneous administration in some patients, which did not result in treatment interruption or discontinuation. The most common adverse events (≥10 percent) were muscle spasms, tinnitus, weight decrease, ear discomfort, nausea and diarrhoea.