Phase II Study of MEDI4736 Monotherapy in Treatment of Recurrent or Metastatic Squamous Cell Carcinoma of the Head and Neck

Inclusion Criteria: * Age ≥18 years * Written informed consent obtained from the patient/legal representative * Histologically confirmed recurrent or metastatic SCCHN * Tumor progression or recurrence during or after treatment with only 1 systemic palliative regimen for recurrent or metastatic disease that must have contained a platinum agent. * Written consent to provide newly acquired tumor tissue (preferred) or archival tissue for the purpose of establishing PD-L1 status. * Confirmed PD-L1-positive SCCHN by Ventana SP263 assay * WHO/ECOG performance status of 0 or 1 * At least 1 measurable lesion at baseline * No prior exposure to immune-mediated therapy * Adequate organ and marrow function * Evidence of post-menopausal status or negative urinary or serum pregnancy test. Exclusion Criteria: * Histologically confirmed squamous cell carcinoma of any other primary anatomic location in the head and neck * Received more than 1 systematic palliative regimen for recurrent or metastatic disease * Any concurrent chemotherapy, Investigational Product, biologic, or hormonal therapy for cancer treatment * Prior randomization or treatment in a previous MEDI4736 and/or tremelimumab clinical study regardless of treatment arm assignment or receipt of any investigational anticancer therapy within 28 days or 5 half-lives * Receipt of last dose of an approved (marketed) anticancer therapy (chemotherapy, targeted therapy, biologic therapy, mAbs, etc) within 21 days prior to the first dose of study treatment * Major surgical procedure within 28 days prior to the first dose of Investigational Product * Any unresolved toxicity NCI CTCAE Grade ≥2 from previous anticancer therapy with the exception of alopecia, vitiligo, and the laboratory values defined in the inclusion criterion * Current or prior use of immunosuppressive medication within 14 days before the first dose of MEDI4736 * History of allogeneic organ transplantation * Active or prior documented autoimmune or inflammatory disorders; * Uncontrolled intercurrent illness * Another primary malignancy * Patients with history of brain metastases, spinal cord compression, or leptomeningeal carcinomatosis * History of active primary immunodeficiency * Known history of previous tuberculosis * Active infection including hepatitis B, hepatitis C or human immunodeficiency virus (HIV) * Receipt of live, attenuated vaccine within 30 days prior to the first dose of MEDI4736 * Pregnant or breast-feeding female patients * Mean QT interval corrected for heart rate (QTc) ≥470 ms calculated from 3 electrocardiograms (ECGs) using Fridericia's Correction * Any condition that, in the opinion of the Investigator, would interfere with evaluation of the IP or interpretation of patient safety or study results