Inclusion Criteria:

   - Eastern Cooperative Oncology Group (ECOG) performance status 0-2

   - Confirmed squamous cell carcinoma (SCC) of the head and neck (oropharynx, oral cavity,
   hypopharynx, or larynx) or skin

   - For patients with oropharyngeal cancer, p16 status is known or can be determined

   - Measurable disease according to Response Evaluation Criteria in Solid Tumors version
   1.1 (RECIST 1.1)

   - Acceptable laboratory results as indicated by protocol

   - Acceptable cardiac function as indicated by protocol

Exclusion Criteria:

   - Received prior epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI)
   therapy for recurrent or metastatic Squamous Cell Carcinoma (e.g., oral EGFR TKIs such
   as erlotinib, gefitinib, or afatinib)

   - Family history of long corrected QT interval (QTc) syndrome

   - Receiving medication that prolongs QT interval ,with a risk of causing Torsades de
   Pointes (TdP), unless ECG meets inclusion criteria while on a stable dose of the
   medication

   - Family history of long QTc syndrome

   - Symptomatic central nervous system (CNS) lesions, or CNS lesions that require therapy

   - Radiation therapy within 2 weeks prior to the first dose of study medication

   - Major surgery within 4 weeks or minor surgery within 2 weeks prior to the first dose
   of study medication

   - Concurrent active malignancy requiring systemic treatment

   - Any other serious uncontrolled medical disorders or psychological conditions that may
   interfere with study conduct including but not limited to: clinically significant
   active infection

   - Pregnant or breast-feeding