A clinical trial to compare atezolizumab with a placebo in people with head and neck cancer who are at a high risk of their cancer returning or getting worse after completion of standard initial therapy.

A Study of Atezolizumab (Anti-PD-L1 Antibody) as Adjuvant Therapy After Definitive Local Therapy in Patients With High-Risk Locally Advanced Squamous Cell Carcinoma of the Head and Neck