PIK3CA and head and neck squamous cell carcinoma: For instance, a dose-escalation phase I trial (NCT02822482) on the effect of combined treatment with the pan-PI3K inhibitor, copanlisib, with cetuximab, an anti-EGFR monoclonal antibody in recurrent and/or metastatic HNSCC patients was terminated due to limited efficacy and unfavorable toxicity [150].