Testing the Addition of an Anti-cancer Drug, BAY 1895344, With Radiation Therapy to the Usual Pembrolizumab Treatment for Recurrent Head and Neck Cancer

This phase I trial evaluates the best dose, possible benefits and/or side effects of combination therapy with elimusertib (BAY 1895344), stereotactic body radiation, and pembrolizumab in treating patients with head and neck squamous cell cancer that has come back (recurrent) and cannot be removed by surgery (unresectable). BAY 1895344 may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. 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. 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 BAY 1895344, stereotactic body radiation therapy in combination with pembrolizumab may shrink or stabilize head and neck squamous cell cancer for longer than treatment with radiation and immunotherapy without BAY 1895344.