NBTXR3, Radiation Therapy, and Pembrolizumab for the Treatment of Recurrent or Metastatic Head and Neck Squamous Cell Cancer

This phase II trial investigates the effect of NBTXR3, radiation therapy, and pembrolizumab in treating patients with head and neck squamous cancer that has come back (recurrent) or has spread to other places in the body (metastatic). NBTXR3 may cause cell destruction when activated by radiation. Radiation therapy, such as stereotactic body radiation therapy, uses special equipment to position a patient and deliver radiation to tumors with high precision. This method may kill tumor cells with fewer doses over a shorter period and cause less damage to normal tissue. And hypofractionated radiation therapy delivers higher doses of radiation therapy over a shorter period of time and may kill more tumor cells and have fewer side effects. Immunotherapy with monoclonal antibodies, such as pembrolizumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Giving NBTXR3, radiation therapy, and pembrolizumab may kill more tumor cells.