Efficacy Study of Pembrolizumab in Relapsed, Locally Recurrent Squamous Cell Cancer of the Head and Neck

Inclusion Criteria: * Has pathologically confirmed SCCHN (oral cavity, oropharynx, larynx, hypopharynx) with evidence of local and/or locoregional recurrence. Laryngeal tumors will only be included if there is evidence of extralaryngeal spread, or there is associated nodal disease. For all other sites, superficial tumors can only be included if there is associated nodal disease. * Has a documented disease-free interval (minimum 16 weeks) after initial curative intent therapy. * Candidate for salvage resection. * Able to provide tissue from diagnostic core biopsy of tumor lesion(s). * Patient has adequate organ function. * Female patient of childbearing potential has a negative serum or urine pregnancy within 72 hours prior to receiving the first dose of study medication. * Female patient of childbearing potential agrees to use adequate birth control. * Male patient with a partner of childbearing potential agrees to use an adequate method of contraception starting with the first dose of study therapy through 120 days after the last dose of study therapy. Exclusion Criteria: * Patient has disease of nasopharyngeal carcinoma histology. * Patient has evidence of metastatic disease. * Patient is currently receiving or has received another investigational agent within 4 weeks prior to study Day 1. * Patient has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of pembroliz…