A Phase II Trial of Afatinib in Patients With Metastatic or Recurrent Squamous Cell Carcinoma of Esophagus

Inclusion Criteria: * Histologically or cytologically confirmed squamous cell carcinoma of esophagus * Age ≥ 20 * ECOG PS 0-2 * Ineligibility for local therapy (surgery or radiotherapy) * Patients who have failed to respond to or receive a first-line, palliative platinum-based chemotherapy 1. Allowed to enroll the patients who have developed the recurrent cancer within 6 months after definitive/neo-adjuvant/adjuvant platinum-based chemotherapy(± radiotherapy), by considering the prior therapy as first-line chemotherapy. 2. Allowed to enroll the patients who cannot undergo platinum-based chemotherapy or concurrent chemo-radiotherapy due to concern for renal function deterioration and the patient intolerance, without prior chemotherapy history. * At least one bidimensionally measurable disease as defined by RECIST ver 1.1 * Adequate organ function for treatment 1. Absolute neutrophil count (ANC) \>=1000 cells/mm3 2. Platelets ≥ 100,000 cells/mm3 3. Estimated creatinine clearance ≥50 mL/min, or serum creatinine \<1.5 x institution upper limit of normal (ULN) using Cockcroft and Gault formulas 4. Bilirubin ≤1.5 x ULN 5. AST (SGOT) ≤2.5 x ULN (5.0 x ULN if hepatic metastases) 6. ALT (SGPT) ≤2.5 x ULN (5.0 x ULN if hepatic metastases) 7. 12-Lead electrocardiogram (ECG) with normal tracing or nonclinically significant changes that do not require medical intervention QTc interval ≤470 msec and without history of Torsades de Pointes or other symptomatic QTc abnormality * The patient who has signed the informed consent prior to conducting study related screening procedures, and who understands that the study may be discontinued at anytime without disadvantages Exclusion Criteria: * Previous treatment with EGFR tyrosine kinase inhibitors * Chemotherapy , immunotherapy or investigational durg within 3 weeks of study entry * Any major operation or irradiation within 4 weeks of baseline disease assessment * Any clinically significant gastrointestinal abnormalities which may impair intake or absorption of the study drug * Patients who confirmed CNS metastasis must have completed any prior treatment for CNS metastasis and steroid therapy for brain metastasis should stopped more 1week and stabled before first dose of study treatment * Patients with known interstitial lung disease * Patients with uncontrolled or significant cardiovascular disease * Previous or concurrent malignancy except for basal or squamous cell skin cancer and/or in situ carcinoma of the cervix, thyroid cancer, or other solid tumors treated curatively and without evidence of recurrence for at least 3 years prior to study entry. * Pregnant or breast feeding women * Other severe acute or chronic medical condition or laboratory abnormality that may increase the risk associated with trial participation