This is a Phase Ib/II study to identify the recommended dose of paclitaxel and nivolumab for further study, and to assess the safety and clinical efficacy of this combined treatment in EBV-related, MSI-high, or PD-L1 positive advanced gastric cancer after first line treatment.~Patients who are EBV-related, MSI-high, or PD-L1 positive will be confirmed by immunohistochemistry (IHC) in a central laboratory (Yonsei Cancer Center), and who meet all eligibility criteria will be enrolled to this study and receive treatment with nivolumab and paclitaxel until progressive disease is confirmed or at least 1 discontinuation criterion is met. It was assumed that about 15% of screened patients will be categorized EBV-related, MSI-high, or PD-L1 positive gastric cancer based on previously reported study results. Part 1>> Phase Ib Phase Ib: 6-12 (The actual number of subjects will be determined by the number of dose escalations to identify MTD and RP2D) Part 2>> Phase II - At the RP2D dose level in phase I part, we will expand phase 2 study for a total of 50 patients. Patients will be treated until the time of disease progression, intolerable toxicities, patient's refusal or consent withdrawal. Tumor assessment will be done every 6 weeks.
This is a Phase Ib/II study to identify the recommended dose of paclitaxel and nivolumab for further study, and to assess the safety and clinical efficacy of this combined treatment in EBV-related, MSI-high, or PD-L1 positive advanced gastric cancer after first line treatment.