Genmab Stock Hits All-Time High as Petosemtamab Cuts Head and Neck Cancer Death Risk by 50% in Phase 3 Trial

Genmab shares surged as much as 21% in Copenhagen on Wednesday, hitting an all-time high on the NASDAQ and marking the stock's biggest single-day gain in more than 14 years, after its experimental cancer drug petosemtamab delivered striking Phase 3 results. The global LiGeR-HN1 trial, evaluating petosemtamab combined with Merck's Keytruda in first-line recurrent or metastatic head and neck squamous cell carcinoma, met both of its primary goals.

Patients receiving the petosemtamab and Keytruda combination saw their risk of death cut by 50% compared with Keytruda alone, and had more than three times the odds of their tumors responding to treatment. Petosemtamab is an investigational IgG1-bispecific antibody that targets both EGFR and LGR5.

Jefferies analysts described the result as a "hat trick" for Genmab, noting that it adds to a string of recent positive pipeline readouts that have raised confidence in the Danish drugmaker. The company is also running additional Phase 3 trials testing petosemtamab in second- and third-line head and neck cancer, broadening the potential commercial opportunity for the drug.