After shepherding the company through its first approval and the successful launch of blockbuster autoimmune drug Vyvgart, argenx co-founder and chief executive Tim Van Hauwermeiren is passing the reins to the Dutch drugmaker’s operating chief.
Karen Massey, who joined the Amsterdam-based immunology specialist as chief operating officer in early 2023, is now set to assume the role of CEO, the company announced on Monday. Hauwermeiren, who’s been with argenx since its inception in 2008, will take a step back to serve as a non-executive director and chairman of the company’s board.
Van Hauwermeiren is himself succeeding Peter Verhaeghe as chairman of the board of directors, with the various leadership changes subject to shareholder approval at argenx’s upcoming annual meeting in early May, the company noted in its press release.
“This leadership evolution comes at the right time and represents a natural step as we prepare for the next phase of growth at argenx,” Verhaeghe said in a statement Monday. “The board and I move forward with strong confidence in Tim as our incoming chairman, Karen as our trusted COO and incoming CEO, and the entire leadership team, to guide the organization towards Vision 2030 and beyond.”
Since the first approval of its flagship FcRn blocker, Vyvgart (efgartigimod), in late 2021, argenx ascended swiftly from biotech upstart to a commercial force in the rare disease space. These days, the company can tout blockbuster sales of its drug across several indications and a market cap of around $50 billion.
Argenx has yet to report full-year revenue for 2025, but in 2024, the company recorded $2.2 billion in product sales, buoyed exclusively by its efgartigimod franchise. In 2025’s third quarter, sales of Vyvgart and Vyvgart Hytrulo clocked in at $1.13 billion, growing 96% over the same period in 2024.
Next on the docket is argenx’s Vision 2030 plan, unveiled at the company's R&D day back in 2024, under which the company has set the goal to push five new preclinical assets into phase 3 development and hold 10 approved indications across Vygart and other near-term potential launches by the start of the next decade. Argenx is also striving to reach 50,000 patients with its current and future medicines under that same 2030 deadline.
“This is a special company with a bright future that is founded on the strength of our science, our entrepreneurial culture, and the deep accountability of our talented teams to transform the lives of our patients,” Massey said in argenx’s announcement Monday.
“My commitment is to elevate the unique argenx DNA as we execute on Vision 2030 and beyond and to ensure we are making the most of this bold opportunity to build the biotech company of the future,” she continued.
Much of argenx’s late-stage development work currently revolves around infused Vyvgart and its subcutaneous sibling Vyvgart Hytrulo. The company’s next most advanced asset, the C2-targeting antibody empasiprubart, is currently in phase 3 testing for multifocal motor neuropathy (MMN) and chronic inflammatory demyelinating polyneuropathy (CIDP).
Argenx has largely prioritized the subcutaneous Vyvgart Hytrulo over its intravenous predecessor in its efforts. Vyvgart Hytrulo was initially cleared by the FDA in generalized myasthenia gravis (gMG) in June 2023 and subsequently picked up a U.S. green light in chronic inflammatory demyelinating polyneuropathy (CIDP) the following year.
More recently, the FDA approved a prefilled syringe formulation of Vyvgart Hytrulo that patients can inject themselves at home. Prior to that FDA nod, Massey told Fierce Pharma in an interview last year that the prefilled syringe could help shift Vyvgart into earlier lines of therapy in gMG and build on the momentum of the drug’s 2024 launch in CIDP.
Massey is set to become one of the few women CEOs spearheading a large commercial pharma company, especially as two prominent female leaders in the industry have recently telegraphed or made their exits.
Back in September, Merck KGaA indicated that Belén Garijo, who helped steer the German healthcare and electronics conglomerate through the COVID-19 pandemic, is planning to end her five-year run at the company in April. Meanwhile, GSK’s Emma Walmsley officially stepped down from her post at the British drug giant on Jan. 1, handing over the CEO title to the company’s former chief commercial officer Luke Miels.