Palbociclib and Cetuximab Versus Cetuximab Monotherapy for Patients With CDKN2A-altered, HPV-unrelated Head and Neck Squamous Cell Carcinoma Who Experienced Disease Progression on a PD-1/L1 Inhibitor

This study is comparing two treatment approaches for people with a specific type of head and neck cancer (HPV-unrelated squamous cell carcinoma) that has a particular gene change called CDKN2A loss and has progressed after immunotherapy. **You may be eligible if...** - You have head and neck squamous cell carcinoma that is not related to HPV (specifically cancers of the oral cavity, larynx, hypopharynx, or HPV-negative oropharynx) - Your tumour has a confirmed CDKN2A gene mutation or deletion on genetic testing - Your cancer progressed during or after treatment with a PD-1 or PD-L1 immunotherapy drug - You have measurable disease on imaging - You have received no more than three prior lines of treatment **You may NOT be eligible if...** - Your head and neck cancer is HPV-positive - Your tumour does not have a CDKN2A alteration - You have not previously received immunotherapy - You have received more than three prior treatment regimens Talk to your doctor to see if this trial is right for you.