A Study of Atezolizumab and Trastuzumab in Combination With Capecitabine and Oxaliplatin in Patients With HER2 Positive Locally Advanced Resectable Gastric Cancer of Adenocarcinoma of Gastroesophageal Junction

Atezolizumab will be administered by IV infusion at a fixed dose of 1200 mg on Day 1 of each 21-day cycle for 3 cycles prior to surgery and 5 cycles after surgery.

Trastuzumab will be administered as an 8 mg/kg IV loading dose and then 6 mg/kg IV on Day 1 of a 21-day cycle for 3 cycles before surgery, and administration will continue after surgery. The first administration of trastuzumab after surgery should also be given at the loading dose of 8 mg/kg.

Capecitabine 1000 mg/m\^2 will be administered twice orally on Days 1-14, repeated every 3 weeks.

Oxaliplatin 130 mg/m\^2 will be administered by IV on Day 1 of a 21-day cycle.