The purpose of this research is to evaluate MTD, Safety and efficacy of GX-051 after intratumoral injection in head and neck cancer patience.

The primary purpose of the study is to determine MTD(Maximum Tolerable Dose) of GX-051 administered in tumor. The second purpose is to evaluate safety and efficacy of GX-051.

Inclusion Criteria:

• Are capable of understanding and complying with the requirements of the study and have signed the informed consent from (ICF).
• Very advanced head and neck cancer aged more than 19.
• Longest distance of the tumor is bigger than 1 cm and capable of Intratumoral injection.
• Baseline ECOG Performance Status 0, 1 or 2.
• Have a life expectancy more than 6 months.

Exclusion Criteria:

• Have no history of prior anticancer treatment.
• Female patients who are pregnant or breast feeding, or adults of reproductive potential who are not using effective birth control methods.Subject who have participated in a clinical trial of an treatment vaccine or immunotherapy in an year.
• Have a tumor which is near a main vessel that can be occured embolism after injection or which has hypervascularity.
• Patients currently receiving anticancer immuno-therapies Patients who have received prior treatment with an stem cell therapy.
• Have autoimmune disease (multiple sclerosis, systemic lupus erythromatosis, thyroiditis, psoriasis, inflammatory bowel diseases etc.).
• Have Graft rejection reaction such as GVHD.
• Have immunodeficiency disease.
• Leukocytes< 3.0 x109/L.
• Absolute neutrophil count < 1.5x109/L.
• Platelet count < 100 x 109/L.
• Have known positive test for hepatitis B surface antigen, hepatitis C antibody, and human immunodeficiency virus (HIV).
• Alanine Aminotransferase (ALT) > 2.5xUNL.
• Aspartate Aminotransferase (AST)> 2.5xUNL.
• Total Bilirubin> UNL.
• Have blood Creatinine> UNL.
• Known allergy to IL-12 or the excipient(s) of the study medication including fetal bovine serum.
• Second primary cancer Metastatic brain tumor or meningioma.
• Have a tumor near a main artery.
• Uncontrolled hypertension.
• Uncontrolled diabetes uncontrolled (arrhythmia).
• Heart failure (more than NYHA Functional Class II); unstable coronary artery disease; myocardial infarction within 6 months.
• Child-Pugh Class C hepatic impairment.
• Severe renal impairment (creatinine clearance < 30 ml/min) or on dialysis.
• Have active infection or history of recurrent infection.
• Patients who have any severe and/or uncontrolled medical conditions or other conditions that could affect their participation in the study.
• Are considered ineligible by the investigator due to a mental disease or CNS disease.
• Administration of any other tumor therapy, including chemotherapy and radiotherapy within 4 weeks(6 weeks in case of nitrosoureas and mytomycin C) before the beginning of study treatment.
• Patients receiving chronic, systemic treatment with immunosuppressive agent(steroid) or immuno-modulator within 2 weeks prior to screening.
• Have participated in another clinical trial within 30 days prior to dosing.