Sales of Amgen’s thyroid eye disease drug Tepezza have slowed, dipping 1% to $457 million in the fourth quarter of 2025.
A subcutaneous formulation of Amgen’s thyroid eye disease drug corrected abnormal eye protrusion as well as the currently approved intravenous version in a late-stage trial—findings that analysts say could give the therapeutic antibody a commercial boost.
“We believe that the availability of the SC [subcutaneous] option could help the Tepezza franchise return to growth” in thyroid eye disease (TED), William Blair said in an investor note on Monday. Analysts at Leerink Partners were likewise bullish about the “more convenient” subcutaneous formulation of Tepezza given Amgen’s readout, which they said could drive uptake.
Tepezza sales dipped 1% to $457 million in the fourth quarter of 2025, versus $460 million during the same period in 2024. Full-year revenues grew 3% to $1.9 billion from $1.85 billion. Leerink on Monday projected global Tepezza sales to hit $2 billion this year.
Topline data presented Monday showed that subcutaneous Tepezza, administered via Amgen’s on-body injector (OBI) technology, elicited a 76.7% proptosis response rate over a 24-week period. Proptosis is a key TED symptom referring to the abnormal bulging of the eyes.
Over the same time span, placebo comparators achieved a 19.6% proptosis response rate. The treatment effect was “statistically significant and clinically meaningful,” Amgen said on Monday.
Subcutaneous Tepezza also resulted in a 3.17-mm average reduction in proptosis at 24 weeks, a key secondary endpoint, as compared to 0.8 mm in placebo. Amgen’s injection hit other secondary outcomes, including overall responder rate, diplopia (double vision) and quality of life.
“We believe that the SC Tepezza results are encouraging,” William Blair wrote on Monday, noting that efficacy “looks in line” with the intravenous formulation.
Tepezza’s benefits also look “greater than SC elegrobart,” the analysts added, referring to Viridian Therapeutics’ TED drug candidate. The biotech released Phase 3 data for elegrobart last week, reporting a 54% proptosis response rate for a monthly dose. This figure jumped to 63% in those treated every eight weeks. The corresponding rate in the placebo arm was 18%.
William Blair at the time were effusive about the findings, writing on March 30 that “these results not only support potential regulatory approvals” for Viridian but also “a compelling commercial profile and significant market opportunity.” The firm nevertheless conceded that the placebo-adjusted efficacy of 36% to 45% came “below the 51%-73% range that investors were looking for.” Viridian’s shares plunged more than 30% in the aftermath of the readout.
Still, William Blair wrote on Monday that Viridian’s elegrobart and Amgen’s new formulation of Tepezza could usher in a new era for the TED space. “SC administration has the potential to expand the TED market, which has been stagnant over the past several quarters,” the analysts said, noting that convenience will become a central consideration in the market.
“Investors will debate the convenience of an on-body injector for Tepezza,” the group contended. Not much is known about Amgen’s injector, though previous disclosures in European Union clinical trials “did note that ‘the investigator or trained designee will administer all doses’” of the drug, the analysts added. This could raise concerns “as to whether patients will be able to administer the on-body injector themselves at home.”
And while the analysts believe that efficacy will be the “most important factor” for medical decision-making, elegrobart could have an edge here, with a self-administered profile that “would likely offer greater convenience and fewer injections.”
There have been no direct head-to-head studies between elegrobart and subcutaneous Tepezza. Cross-study comparisons are inconclusive.
