Viridian Therapeutics said Tuesday its injectable drug for thyroid eye disease scored in a second late-stage trial, strengthening its position as a competitive threat to Amgen’s blockbuster therapy Tepezza.
Viridian has already disclosed that its drug, an under-the-skin injection called elegrobart, met its objectives in a study of people with “acute” thyroid eye disease. On Tuesday, the company claimed success in another late-stage trial of people whose disease has transitioned to a “chronic” phase.
According to Viridian, once-monthly and every-other-month doses of elegrobart were associated with response rates of 50% and 54%, respectively, after 24 weeks. By comparison, 15% of placebo recipients hit that mark, a difference the immune drugmaker described in its statement as “highly statistically significant.”
The once-monthly dose of elegrobart also helped relieve cases of double vision, or diplopia, with 61% of those getting the drug responding versus 38% of people in the control group. The longer-lasting dose missed statistical significance, Viridian said.
The “vast majority” of side effects associated with treatment were mild and generally in line with what’s expected of drugs in Viridian’s class. Rates of hearing impairment — an issue with Tepezza — were low in both dose groups. Among people who got the drug, 91% completed their full course, and investigators didn’t observe any treatment-related serious adverse events.
Viridian is on track to seek regulatory clearance by the first quarter of next year.
The results represent a needed boost for Viridian, which is aiming to break into a market currently dominated by Amgen but has faced investor doubts about its prospects.
Amgen’s Tepezza is currently the only approved treatment for thyroid eye disease, an autoimmune condition that can cause eye bulging, redness and double vision. It regularly generates about $2 billion in annual sales.
Viridian is among the companies aiming to top Tepezza in one way or another. The company has two drugs in testing that, like Tepezza, block an inflammation driver known as IGF-1R. One, veligrotug, is an intravenous infusion that Viridian is positioning as a faster-acting alternative. That drug could be approved by U.S. regulators by the end of June. The other, elegrobart, is administered through an under-the-skin injection able to be given at home.
In March, Viridian said elegrobart achieved positive results in a Phase 3 trial in people with “active” disease — the initial phase when inflammation begins. Viridian shares tumbled by more than 30%, though, as the findings missed investor expectations and sparked debate about the drug’s commercial prospects. And shortly thereafter, Amgen said a version of Tepezza administered via an on-body injector hit its goals in a late-stage study, further pressuring Viridian.
The data posted Tuesday from Viridian calmed some of investors’ fears, according to analysts. In a Tuesday client note, Stifel analyst Alex Thompson called the findings “highly competitive” within the thyroid eye disease market, even when accounting for Amgen’s latest Tepezza data.
Investors had also feared that a study failure in the chronic setting might imperil an approval filing. But the positive results “pave the way for a filable package” and “alleviate concerns” regarding the earlier results in acute disease, he added.
Leerink Partners’ Thomas Smith went a step further, calling the results the “strongest [subcutaneous] dataset generated to date” in chronic disease.
Company shares surged about 30% in Tuesday morning trading.
