This is a study to establish a safe and feasible dose for prophylactic use of a combination of gabapentin and ketamine in head and neck cancer patients undergoing chemoradiation.

Ficerafusp alfa is directed against two targets, Epidermal Growth Factor Receptor (EGFR) and Transforming Growth Factor beta (TGF-).

This study intends to evaluate the safety and efficacy of ficerafusp alfa in combination with pembrolizumab versus placebo with pembrolizumab in 1L PD-L1-positive, recurrent or metastatic Head and Neck Squamous Cell Carcinoma (HNSCC).

The goal of this phase I clinical trial is to evaluate the usefulness of an imaging test (zirconium Zr89 panitumumab \[89Zr panitumumab\]) with positron emission tomography (PET)/computed tomography (CT) for diagnosing the spread of disease from where it first started (primary site) to other places in the body (metastasis) in patients with head and neck squamous cell carcinoma. Traditional PET/CT has a low positive predictive value for diagnosing metastatic disease in head and neck cancer. 89Zr panitumumab is an investigational imaging agent that contains radiolabeled anti-EGFR antibody which is overexpressed in head and neck cancer. The main question this study aims to answer is the sensitivity and specificity of 89Zr panitumumab for the detection of indeterminate metastatic lesions in head and neck cancer.

Participants will receive 89Zr panitumumab infusion and undergo 89Zr panitumumab PET/CT 1 to 5 days after infusion. Participants will otherwise receive standard of care evaluation and treatment for their indeterminate lesions.

Researchers will compare the 89Zr panitumumab to standard of care imaging modalities (magnetic resonance imaging (MRI), CT, and/or PET/CT).