In this open-label , phase 3 , randomised controlled trial conducted in 101 centres in 19 countries , we enrolled patients aged 18 years or older with histologically or cytologically confirmed HNSCC that was recurrent , metastatic , or both who had progressed on or after first-line platinum-based therapy , were not amenable for salvage surgery or radiotherapy , and who had an Eastern Cooperative Oncology Group ( ECOG ) performance status of 0 or 1 .