A phase 3 randomized, open-label study to evaluate the efficacy and safety of petosemtamab plus pembrolizumab vs pembrolizumab in first-line treatment of recurrent or metastatic PD-L1+ head and neck squamous cell carcinoma

This is a phase 3 study of the investigational medicine petosemtamab in participants with head and neck cancer that has spread (metastatic) or has come back (recurrent), Petosemtamab is an antibody treatment designed to interact with 2 targets at the same time. These are the proteins called EGFR and LGR5. These interactions may help to fight cancer. In this study petosemtamab is given together with the approved anticancer treatment pembrolizumab that may help the immune system fight cancer. Head and neck cancer includes a group of solid tumour cancers which can occur within the mouth, tongue and/or throat.The purpose of this study is to compare the activity to destroy tumours or prevent them from growing (anti-tumour activity), and the safety of the treatment of petosemtamab when used in combination with another, already approved drug, named pembrolizumab.Participants taking part in this trial will receive the investigational drug, petosemtamab in combination with pembrolizumab or pembrolizumab alone. Participants will be randomly assigned to receive the study drug plus pembrolizumab or pembrolizumab alone and will have a 50% chance of receiving either. This is an open-label study which means that both the participant, the Study Doctor and Sponsor, will know which treatment the participant has been assigned to.All treatments, whether petosemtamab plus pembrolizumab or pembrolizumab alone, will be given as an intravenous (IV) infusion in the arm. Infusion of the study drug (petosemtamab) will be given every 2 weeks, and the infusion of pembrolizumab will be every 6 weeks.Approximately 500 participants, aged 18 and older, will take part in this study globally. Participants will go through a screening period and then participants will receive petosemtamab until the cancer worsens, they have intolerable side effects, or they withdraw from the study. Pembrolizumab treatment will last for up to 2 years. The total study duration will be about 3 and a half years.