Genmab surged to record highs after its petosemtamab regimen posted positive late-stage results in first-line head and neck squamous cell carcinoma. At an early analysis, petosemtamab combined with pembrolizumab (Keytruda) cut the risk of death by half versus Keytruda alone in patients whose tumors are PD-L1 positive, while also meeting dual primary objectives on response rates and survival. The update is Genmab’s third consecutive positive late-stage readout in recent weeks. The company said it will share detailed results with global regulators and present data at an upcoming medical meeting. Investors appeared to focus on commercial timing as well: the company is positioning petosemtamab to grow into a larger franchise as it braces for Darzalex exclusivity loss. Genmab acquired petosemtamab through its 2024 buyout of Merus. Analysts also framed the readout as reinforcing Genmab’s broader momentum across oncology, including a Phase 3 win for Epkinly with AbbVie and late-stage progress for rinatabart sesutecan in ovarian cancer.