Genmab said its petosemtamab plus Merck’s Keytruda cut the risk of death by half versus Keytruda alone in a first-line regimen for PD-L1–positive head and neck squamous cell carcinoma, meeting dual response-rate and survival objectives at early analysis. The company plans to share detailed data with regulators and present at an upcoming medical meeting. The result adds to Genmab’s recent streak of late-stage wins and reinforces petosemtamab as a key growth engine as it braces for Darzalex exclusivity expiry. Petosemtamab is a bispecific EGFR/LGR5 antibody acquired through Genmab’s purchase of Merus. Genmab’s market value jumped more than $7 billion on the update, with management framing the dataset as a step toward establishing a new standard of care in the setting.