Why argenx (ENXTBR:ARGX) Is Down 7.7% After Halting Its Phase 3 Thyroid Eye Disease Trials

• On 15 December 2025, argenx SE said it would discontinue its Phase 3 UplighTED trials of subcutaneous efgartigimod in adults with moderate to severe thyroid eye disease after an Independent Data Monitoring Committee found the study was unlikely to meet its efficacy goals, despite a favorable safety profile and no new safety signals.
• The company now plans a full analysis of the interim data to understand why the drug underperformed on proptosis response and other endpoints, and to extract biological insights that could guide future thyroid eye disease research.
• We’ll now examine how discontinuing efgartigimod’s Phase 3 thyroid eye disease program, despite solid safety, may reshape argenx’s investment narrative.

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argenx Investment Narrative Recap

To own argenx, you need to believe in VYVGART as a durable, expanding autoimmune franchise and in the company’s ability to convert its FcRn science into multiple indications. The setback in thyroid eye disease removes one potential growth driver, but does not materially change the near term focus on VYVGART’s ongoing gMG and CIDP roll out or the key risk of heavy dependence on a single product.

The most relevant recent development alongside this news is argenx’s Q3 2025 results, which showed US$1,151.34 million in quarterly revenue and US$344.26 million in net income. Those figures underscore how central VYVGART already is to the income statement, which makes any clinical disappointment outside the core indications a reminder that concentration risk is still front and center for shareholders.

However, investors should be aware that growing reliance on VYVGART leaves argenx exposed if...

Read the full narrative on argenx (it's free!)

argenx's narrative projects $6.9 billion revenue and $2.6 billion earnings by 2028.

Uncover how argenx's forecasts yield a €797.32 fair value, a 10% upside to its current price.

Exploring Other Perspectives

Seven fair value estimates from the Simply Wall St Community span roughly US$528 to over US$2,093 per share, showing very different expectations. When you set those views against argenx’s reliance on VYVGART as a single primary revenue engine, it becomes clear why checking multiple opinions on the company’s prospects can matter.

Explore 7 other fair value estimates on argenx - why the stock might be worth over 2x more than the current price!

Build Your Own argenx Narrative

Disagree with existing narratives? Create your own in under 3 minutes - extraordinary investment returns rarely come from following the herd.

• A great starting point for your argenx research is our analysis highlighting 3 key rewards that could impact your investment decision.
• Our free argenx research report provides a comprehensive fundamental analysis summarized in a single visual - the Snowflake - making it easy to evaluate argenx's overall financial health at a glance.

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This article by Simply Wall St is general in nature. We provide commentary based on historical data and analyst forecasts only using an unbiased methodology and our articles are not intended to be financial advice. It does not constitute a recommendation to buy or sell any stock, and does not take account of your objectives, or your financial situation. We aim to bring you long-term focused analysis driven by fundamental data. Note that our analysis may not factor in the latest price-sensitive company announcements or qualitative material. Simply Wall St has no position in any stocks mentioned.

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