Argenx autoimmune drug study fails in blow to expansion hopes

Argenx autoimmune drug study fails in blow to expansion hopes

  21 Dec 2023

Dive Brief:

  • Argenx lost a quarter of its value Wednesday after reporting the second research setback in two months for its bid to expand use of its only approved drug.
  • The latest study, called Address, showed no significant benefit for Argenx’s Vyvgart Hytrulo in people with two forms of an autoimmune skin disease called pemphigus. The condition causes painful blisters that can break open and leave patients at risk of infection.
  • The news follows an announcement in late November that the drug failed in a late-stage study of patients with primary immune thrombocytopenia. Vyvgart Hytrulo is currently approved to treat a condition called myasthenia gravis that can cause serious muscle weakness.

Dive Insight:

Argenx had been a Wall Street favorite, raising $1.1 billion from investors in a secondary stock offering earlier this year. The company impressed analysts with initial sales for an infused version of Vyvgart, then followed that up with an approval for the subcutaneous type sold as Vyvgart Hytrulo in June.

Study results also went Argenx’s way earlier in the year. In July, the company reported a successful trial of Vyvgart Hytrulo in patients with chronic inflammatory demyelinating polyneuropathy, or CIDP. Even after the latest setback, analysts at Stifel estimate that Vyvgart could eventually be a $6 billion drug based on sales in myasthenia gravis and CIDP.

But the path forward for Argenx is now “murkier than before,” Stifel analyst Alex Thompson wrote in a note to clients. Investors agreed, sending the Dutch biotech’s shares down more than $110 to less than $340 apiece in early trading Wednesday morning.

“Confidence is understandably shaken,” Raymond James analyst Danielle Brill wrote in an investor note. Yet Brill also sees room for Vyvgart sales to reach $5 billion to $6 billion on myasthenia gravis and CIDP alone.

The Address study was designed to show Vyvgart Hytrulo could help more pemphigus patients achieve complete remission from their disease while on a minimal dose of corticosteroids. But Argenx said patients had a higher-than-expected response to the steroid treatment, and the trial ended up showing little difference between the patients on Vyvgart and those given a placebo.

Given the results, Argenx is deprioritizing pemphigus development. The company also decided to delay a decision on proceeding with a two-part study called Ballad for patients with a similar condition called bullous pemphigoid. The company said it will instead “wait for learnings from all currently enrolled patients and consider a new trial design for the path forward.”

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