Genmab shares doubled in three months after the Danish biotech reported three successful Phase 3 cancer drug trials in October. Shares surged 48% last week, including a 29% single-day jump following positive results for petosemtamab, an experimental head and neck cancer treatment.
The $35 billion company reported that petosemtamab combined with Merck's Keytruda reduced the risk of death by 50% compared with Keytruda alone in patients with recurrent or metastatic head and neck cancer. Genmab also announced that Rina-S reduced the risk of death by 57% versus chemotherapy in ovarian cancer trials, and Epkinly, co-developed with AbbVie, reduced the risk of disease progression or death by 51% in lymphoma trials.
CEO Jan van de Winkel called the breakthroughs "a completely new era" for the company. Historically, Genmab made money from royalties on drugs developed with partners, including Johnson & Johnson's Darzalex, which is expected to generate $16.5 billion to $16.9 billion in sales this year with Genmab receiving royalties of up to 20%. The company is now shifting its business model to retain much larger shares of revenue from its own treatments.
Van de Winkel said he expects petosemtamab to become a "multi-billion dollar drug." Jefferies analysts estimated petosemtamab could generate $3.5 billion in peak annual sales treating recurrent or metastatic head and neck cancer, with expansion into locally advanced disease adding another $3.5 billion.
Genmab acquired petosemtamab through an $8 billion purchase of Merus in 2025 and Rina-S through a $1.8 billion acquisition of ProfoundBio in 2024. The company borrowed $5.5 billion to help fund the Merus deal, relying on royalty income as a financial backstop. Genmab now has 15 Phase 3 trials across its three lead compounds.
Van de Winkel said the company is expanding its sales presence in Europe and seeking to reach more cancer patients through community healthcare in the U.S., aiming for its majority-owned medicines to reach around 500,000 patients by the 2030s, up from fewer than 30,000 today. He acknowledged potential interest from larger drugmakers but stressed his ambition remained to build an independent European biotech.