Efficacy results from the ToGA trial: A phase III study of trastuzumab added to standard chemotherapy (CT) in first-line human epidermal growth factor receptor 2 (HER2)-positive advanced gastric cancer (GC)

LBA4509 Background: Advanced GC is an incurable disease; new and less toxic treatments are needed. HER2 overexpression has been reported in 6–35% of stomach and gastroesophageal tumors. Trastuzumab (H; Herceptin), a monoclonal antibody against HER2, has shown survival benefits when given with CT in patients (pts) with HER2-positive early and metastatic breast cancer. The ToGA study is the first randomized, prospective, multicenter, phase III trial to study the efficacy and safety of H in HER2- positive GC. Methods: Pts with HER2-positive gastroesophageal and gastric adenocarcinoma (locally advanced, recurrent, or metastatic) were randomized to receive H+CT (5-fluorouracil or capecitabine and cisplatin) q3w for 6 cycles or CT alone. H was given until disease progression. The primary end point was overall survival (OS); secondary end points included overall response rate (ORR), progression-free survival, time to progression, duration of response, and safety. An interim analysis was planned at 75% of deaths ...