Pembrolizumab, Olaparib, Recurrent/Advanced Gastric and Gastro-esophageal Junction(GEJ) Cancer

Exclusion Criteria

• •1. A WOCBP who has a positive urine pregnancy test within 72 hours prior to allocation
• •2. Has received prior systemic anti-cancer therapy including investigational agents within 2 weeks prior to allocation.
• •3. Has received prior radiotherapy within 2 weeks of start of study treatment.
• •4. Has received a live vaccine within 30 days prior to the first dose of study drug.
• •5. Is currently participating in or has participated in a study of an investigational agent including trastuzumab or has used an investigational device within 4 weeks prior to the first dose of study treatment.
• •6. Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy (in dosing exceeding 10 mg daily of prednisone equivalent) or any other form of immunosuppressive therapy within 7 days prior to the first dose of study drug.
• •7. Has a known additional malignancy that is progressing or has required active treatment within the past 5 years.
• •8. Has known active CNS metastases and/or carcinomatous meningitis.
• •9. Has severe hypersensitivity (≥Grade 3) to pembrolizumab and/or any of its excipients, PARP inhibitor and paclitaxel.
• •10. Has active autoimmune disease that has required systemic treatment in the past 2 years
• •11. Has a history of (non-infectious) pneumonitis that required steroids or has current pneumonitis.
• •12. Has an active infection requiring systemic therapy.
• •13. Has a known history of Human Immunodeficiency Virus (HIV).
• •14. Has an active of Hepatitis B (defined as Hepatitis B surface antigen \[HBsAg\] reactive and HBV titer \>2000 IU/ml) or known active Hepatitis C virus (defined as HCV RNA is detected) infection.
• •15. Has an active TB (Bacillus Tuberculosis) with treatment.
• •16. Participant has received previous allogenic bone-marrow, tissue/solid organ transplant or double umbilical cord transplantation (dUCBT).