T-Dxd in Combination With Ramucirumab as HER2 Low Gastric or Gastroesophageal Junction (GEJ) Adenocarcinoma

"Phase Ib will use a standard 3+3 scheme with the planned doses of T-DXd (4.4\~6.4 mg/kg) once every 3 weeks in combination with Ramucirumab 8mg/kg administered once every 2 weeks.~* Dosing Regimen~ * Trastruzumab deruxtecan : One IV infusion every 3 weeks on Day 1 of each 21-day cycle~ * Ramucirumab : One IV infusion on every 2 weeks on Day 1,15 of each 28-day cycle"