A Phase I-II Study of HM781-36B Combined With Paclitaxel and Trastuzumab in HER-2 Positive Advanced Gastric Cancer

Inclusion Criteria: 1. Histologically or cytologically confirmed advanced gastric cancer including gastroesophageal junction adenocarcinoma 2. At least one measurable lesion defined by RECIST(v1.1) 3. FISH+ or IHC3+ (regardless of FISH results) 4. Age≥19 5. ECOG ≤ 2 6. Life expectancy ≥ 12 weeks 7. Adequate bone marrow and no abnormal heart and lung function 8. No radiotherapy, other anticancer drugs or immunotherapy is allowed during this study 9. Subjects must provide written informed consent prior to performance of study specific procedures or assessments, and must be willing to comply with treatment and follow up assessments and procedures Exclusion Criteria: 1. Patients with a history of hypersensitivity to Trastuzumab and who have been treated with medicine including Cremophor EL 2. Patients who have a current active malignancy other than gastric adenocarcinoma (with exception of non-melanoma skin cancer or cervical cancer in situ) 3. Patients who have previously received taxane-based chemotherapy 4. The presence of central nervous system metastases 5. Patients who have a blood tumor such as leukemia, or who had previously received, or are planning to receive, the bone marrow transplant 6. Patients with uncontrolled infection 7. Patients who have GI malabsorption or difficulty taking oral medication 8. Patients with following diseases are excluded: 9. Patients with psychiatric or congenital disorder which can affect adherence or make hard to follow the requirements of the protocol 10. Pregnant or breastfeeding women or women of childbearing who do not use an appropriate method of contraception (male patient should also use an appropriate method of contraception)