Genmab A/S (NASDAQ:GMAB) today announced updated results from a Phase 2 trial evaluating petosemtamab, an investigational IgG1-bispecific antibody targeting the epidermal growth factor receptor (EGFR) and leucine-rich repeat containing G-protein-coupled receptor 5 (LGR5), in combination with pembrolizumab for first-line (1L) treatment of recurrent/metastatic PD-L1+ head and neck squamous cell carcinoma (r/m HNSCC). In the 1L combination arm, treatment with petosemtamab plus pembrolizumab achieved a median overall survival (OS) of 28.2 months, associated with an overall response rate (ORR) of 63% and median progression free survival (mPFS) of 9.0 months in efficacy-evaluable patients (n=43), including a complete response (CR) rate of 19%. The findings were presented at the European Society for Medical Oncology (ESMO) Congress 2026, held in Madrid, Spain.