Tepezza Just Lost the Throne It's Held for Over Six Years
For six years, Tepezza was the only FDA-approved drug for thyroid eye disease, pulling in nearly $2 billion a year. Viridian's newly approved Lumvoa just crashed the party, and the implications for patients, pricing, and Amgen's bottom line are bigger than the stock pop suggests.
For over six years, patients with thyroid eye disease had exactly one FDA-approved drug option. One. If you needed treatment for the autoimmune condition that makes your eyes bulge painfully from their sockets, you went to your doctor, and your doctor prescribed Tepezza. That's it. No alternatives, no competition, no negotiating leverage.
That era just ended.
The FDA approved Viridian Therapeutics' Lumvoa (veligrotug) for the treatment of thyroid eye disease, or TED. It's the first real competitor to Amgen's nearly $2 billion-a-year franchise, and Viridian's stock jumped about 6% in after-hours trading on the news.
But the bigger story isn't about one company's stock price. It's about what happens when a monopoly finally gets a rival.
A $2 Billion Kingdom, Built on Being the Only Option
To understand why this matters, you need to understand what Tepezza has been. Amgen acquired it as part of its $27.8 billion purchase of Horizon Therapeutics in October 2023. The drug pulled in $1.9 billion in sales in 2024 and roughly the same in 2025. For context, that's about 5-6% of Amgen's entire revenue, from a single product treating a single disease.
And yet, Tepezza has only treated a fraction of the roughly 100,000 U.S. patients with TED. The franchise essentially stopped growing around 2022, hovering near $1.9 billion ever since. Think of it like a restaurant that charges $200 a plate: you don't need many customers to make great money, but you're not exactly packing the house.
Why the plateau? A few reasons. Tepezza costs north of $200,000 per treatment course. Insurance hoops are real. And the drug comes with some baggage: hearing impairment (including potential permanent hearing loss) and hyperglycemia that make doctors think twice before prescribing it, especially for patients with diabetes or ear problems.
So you had an expensive monopoly drug with known safety concerns, serving a fraction of eligible patients. That's basically an engraved invitation for a competitor.
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Enter Viridian, the Company That Reinvented Itself
Viridian's origin story reads like a career pivot gone right. The company started life as miRagen Therapeutics, a microRNA outfit that became publicly listed through a reverse merger in early 2017. By 2020, it had made a sharp left turn: acquiring an antibody originally developed for cancer (by ImmunoGen and Sanofi) and repurposing it for thyroid eye disease.
In January 2021, miRagen renamed itself Viridian Therapeutics and went all-in on TED. It was a bold bet. The company was essentially saying: "We think we can build a better version of the only approved drug for this disease." That's the biotech equivalent of opening a burger joint across the street from In-N-Out.
Same Target, Potentially Better Profile
Both Lumvoa and Tepezza work by blocking the same receptor: IGF-1R (insulin-like growth factor-1 receptor). In TED, rogue autoantibodies activate this receptor on cells behind the eyes, triggering inflammation that causes swelling, bulging, double vision, and pain. Block the receptor, and you shut down the cascade.
So the mechanism is the same. The differences are in execution.
Lumvoa's Phase 3 trial in active TED, called THRIVE, posted strong numbers. 70% of patients saw meaningful reduction in eye bulging, compared to just 5% on placebo. Over half (53%) responded after a single infusion, just three weeks in. And 54% achieved complete resolution of double vision, versus 12% on placebo.
Those figures look competitive with Tepezza's historical results (roughly 70-80% proptosis response in active TED). No head-to-head trial exists, so cross-trial comparisons come with caveats. But the ballpark is similar.
Where Lumvoa may pull ahead is in two areas. First, chronic TED. Viridian's THRIVE-2 trial is the first global Phase 3 to show statistically significant improvement in double vision for chronic disease, a population where Tepezza's evidence is thinner. Second, safety. Across Viridian's trials, hearing impairment rates were low, and the overall profile looked cleaner than what doctors have seen with Tepezza.
The treatment itself involves five IV infusions over 12 weeks, each lasting about 30 minutes. It's a defined course, not an indefinite commitment.
The Pricing Gambit: Matching, Not Undercutting
Viridian told Reuters it plans to price Lumvoa at parity with Tepezza on a course-of-therapy basis. No discount. No price war.
This is a deliberate strategic choice. Rather than competing on cost, Viridian is betting that doctors will switch patients based on clinical profile: broader label coverage (active and chronic TED), potentially fewer hearing and blood sugar concerns, and strong efficacy data. It's the "we're just as expensive, but arguably better" play.
Analysts seem to buy it. 16 out of 17 covering analysts rate the stock a Buy or better, with an average 12-month price target around $38 to $41. That implies significant upside from the stock's recent trading level near $19. Wedbush went even higher, raising its target to $43 and pointing to meaningful revenue starting in 2027.
The bears aren't absent, though. H.C. Wainwright sits at a more conservative $22 target, flagging concerns about how quickly Lumvoa can ramp up against an entrenched incumbent. Launching a specialty biologic is hard. Payer negotiations, infusion center logistics, physician inertia: these are real obstacles even with a good drug.
What This Means for Patients (and Amgen)
For the roughly 100,000 Americans living with TED, this approval matters beyond corporate scorecards. Many patients still rely on high-dose steroids, orbital radiation, or multi-stage surgeries because Tepezza's safety profile or cost puts it out of reach. Having a second approved option with a potentially gentler side-effect profile could genuinely expand who gets treated.
For Amgen, the math gets uncomfortable. Tepezza's $1.9 billion revenue has been essentially flat for three years. Now it faces a competitor with comparable efficacy, a broader label, and a narrative around better tolerability. Even modest share loss in a stagnant market hurts.
The Bigger Picture
Viridian isn't done, either. The company has a subcutaneous IGF-1R antibody (elegrobart) in Phase 3 trials for chronic TED. Early data from the REVEAL-2 trial showed proptosis response rates of 50-54% versus 15% on placebo, with low hearing impairment rates. If that program succeeds, patients could eventually self-inject at home instead of visiting an infusion center.
The TED market was valued at roughly $2.3 billion in 2023 across seven major markets, and Tepezza captured the lion's share. With Lumvoa now approved and a subcutaneous option potentially on the way, we're watching a monopoly transform into a competitive market in real time.
Six years is a long time to be the only game in town. For Amgen, the party's over. For patients, it might just be getting started.
Clinical & Regulatory
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