Safety Study of GC1118 (Recombinant Human Anti-EGFR Antibody) in Patients With Advanced Solid Cancer

Inclusion Criteria: * Willing and able to sign a written informed consent * Nineteen (19) years of age or older * For Part A and Part C, all stage IV advanced solid cancers For Part B, stage IV of gastric cancer, colorectal cancer or other cancer * Cohort1: Metastatic CRC (K-RAS wild), No prior treatment with EGFR antibody therapeutics * Cohort2: Metastatic CRC (K-RAS wild), Progressed over EGFR antibody therapeutics * Cohort3: Advanced gastric or gastroesophageal junction cancer(EGFR++ or +++ /HER2-) * For Part A and Part C, refractory solid tumors to conventional therapy (Progressive disease during or after previous conventional therapy) * Eastern Cooperative Oncology Group (ECOG) Performance Status of less than or equal to 1 * Life expectancy of greater than or equal to 3 months * Availability of a new tumor biopsy or able to obtain unstained slides of tumor within 3 years * For Part B, at least one measurable tumor mass by RECIST v1.1 * Acceptable laboratory parameters * If all AEs caused by the previous anti-cancer therapies including surgery, chemotherapy and radiation therapy have recovered to CTCAE grade 1 or below (except alopecia) Exclusion Criteria: * Has had any major surgery or any therapy within the last 4 weeks and/or not recovered from prior therapy * Has had chemotherapy, surgery or radiotherapy within the previous 4 weeks * Confirmed brain metastases * Chronic Hepatitis C or known HIV positive patients * Liver Cirrhosis or active hepatitis B virus (HBV) carrier * Clinically significant interstitial pulmonary disease * Has received prior treatment with cetuximab or anti-EGFR antibody therapy is not permitted in Part B(however, allowed in Part A and Part C) * Clinically significant cardiac disease or impaired cardiac function * Acute or subacute intestinal obstruction or Inflammatory bowel disease * Has had immunotherapy, chemotherapy or hormonal therapy prohibited as per study protocol * Has participated in any study using an investigational drug during the previous 4 weeks * Known hypersensitivity to the study drug * History of second primary malignancy within 3 years prior to starting study treatment (excluding early gastric cancer, thyroid cancer, cervical cancer or skin cancer) * Severe renal impairment * Severe hepatic impairment * Current active infection * Known KRAS-mutation for Part A and Part C, Known KRAS-mutation for Part B or BRAF matant * Medical or psychiatric illness that, in the opinion of the investigator, may affect compliance with scheduled visits * Pregnant (potentially fertile patients) or lactating women * Patients refuse to use acceptable forms of contraceptions from the time of consent through six months after the study drug administration