Amgen said an injectable version of its blockbuster eye disease drug Tepezza hit both goals in a key late-stage trial that could help the company fend off competition from an emerging rival.
According to Amgen, a form of the thyroid eye disease drug Tepezza that’s delivered via an on-body injector instead of an intravenous infusion met its main objective as well as a key secondary endpoint in the study. Notably, the newer version, Tepezza OBI, appeared comparable to the marketed medicine, displaying “IV-like efficacy,” said research chief Jay Bradner, in the statement.
Specifically, 77% of patients treated with Tepezza OBI responded to treatment over the 24-week study period, meaning their eye bulging, or “proptosis,” was reduced by a specific threshold thought to be meaningful. By comparison, about 20% placebo recipients responded. Treatment was also associated with a mean 3.17 millimeter reduction in proptosis, versus a 0.80 millimeter decline for the placebo group.
Amgen didn’t provide other study details, but said that treatment led to "statistically significant and clinically meaningful improvements” across several other study goals and that the safety results were “consistent” with the known profile of the marketed drug. Full results will be disclosed at an upcoming medical meeting.
“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,” Bradner added.
Tepezza is the first and only approved treatment for thyroid eye disease, an autoimmune condition linked to Graves’ disease that can cause double vision, redness and eye bulging. Amgen gained the drug in a $28 billion buyout of Horizon Therapeutics in 2023. Tepezza had already become a blockbuster before that deal and, since then, has regularly generated close to $2 billion in annual sales.
Yet Tepezza’s numbers have stagnated over the last several quarters, wrote William Blair analyst Matt Phipps in a Monday note to clients. A subcutaneous alternative could help “expand the [thyroid eye disease] market,” and usher in additional growth, he noted.
Amgen isn’t alone in pursuing a more convenient option. Viridian Therapeutics has two drugs in advanced development, one of which is supposed to be a faster-acting infusion and the other a subcutaneous injection. The IV drug, veligrotug, could be cleared by the Food and Drug Administration by the end of June. Viridian recently revealed Phase 3 data for its under-the-skin injection, elegrobart.
Comparing drugs across trials can be misleading. Still, elegrobart’s results — a 54% to 63% reduction in proptosis after six months, depending on the dose — missed investor expectations and sent Viridian shares down by about a third last week.
Viridian shares tumbled by another 20% Monday, as analysts debated the merits of its therapy in the wake of Amgen’s results. Leerink Partners’ Thomas Smith rallied to Viridian’s defense, arguing that an on-body injection device is a “sub-optimal product offering” compared to elegrobart, which is delivered via an autoinjector and dosed less frequently.
Phipps, of William Blair, also noted how safety details will be crucial in assessing the difference between the two therapies, given the association between Tepezza and a type of hearing impairment.
Overall, though, a subcutaneous option could help the Tepezza “franchise return to growth” in thyroid eye disease, where “access to infusion centers has been a key limiting factor,” Phipps wrote.
