Star drugs have suffered a severe setback! Argenx (ARGX.US) terminates thyroid eye disease drug trials, and its stock price recorded the biggest drop in seven months

The Zhitong Finance App learned that after Belgian biotech company Argenx SE (ARGX.US) said it would stop a late-stage trial of an experimental drug to treat autoimmune diseases affecting the eyes, its stock price recorded the biggest drop in seven months. Argenx said the drug Efgartigimod (brand name Vyvgart), which is being evaluated in adult patients with moderate to severe thyroid eye disease, will stop testing based on the recommendations of an independent data monitoring committee. The company's stock price once fell 9.7% in the Brussels stock market, the biggest drop since May 8. As of press release, the US stock was down 5.31% in the premarket.

The end of this trial impacted the company's goal of treating 50,000 patients by 2030. Argenx expects to announce the results of four other late-stage clinical trials for various autoimmune diseases next year, three of which involve Vyvgart.

Analyst Michael Shah pointed out in the report that the termination of the thyroid eye disease trial was “unexpected, which directly meant that a market of about 100,000 potential patients in the US was excluded.” He added that this “added an additional burden to the readout of critical data” for success in the fields of ocular myasthenia gravis, myositis, and primary immune thrombocytopenia in 2026.

Argenx said an independent data monitoring committee assessed the invalidity of non-blind data from late-stage study patients who completed 24 weeks of treatment. The company plans to share data from these studies at future medical conferences. According to a statement on Monday, the drug showed good safety and tolerability characteristics, and no new safety signals were found.

Argenx's stock price has soared by more than 8,000 percent since it was listed in Brussels in July 2014, and the company's fate is closely linked to its only approved drug, Vyvgart. This major drug has now been approved to treat systemic myasthenia gravis and chronic inflammatory demyelinating polyneuropathy, and has been approved in Japan to treat primary immune thrombocytopenia.

Other analysts said that Argenx's long-term outlook remains positive.

Sebastian van der Scott, an analyst at Van Lanschot Kempen, wrote in a report: “While thyroid eye disease could have added $800 million to our current $11 billion peak sales forecast, this is only a fraction of our valuation of Vyvgart. We will look at the emotional decline as an opportunity to buy one of Europe's must-have biotech stocks.”