Trastuzumab beyond first progression in cases of HER2-positive advanced gastric or gastro-esophageal junction cancer: Initial results from KSCC1105, a trastuzumab observational cohort study.

93Background: The concept of using trastuzumab (Tmab) beyond progression (TBP) is currently accepted in HER2-positive metastatic breast cancer. However, TBP has never been investigated in cases of HER2-positive advanced gastric or gastro-esophageal junction (G/GEJ) cancer. KSCC1105 is an observational cohort study designed to investigate the clinical outcomes associated with Tmab combined with chemotherapy including TBP strategy in part, as used in clinical practice, for the treatment of advanced G/GEJ cancer. Methods: Patients (pts) with advanced HER2-positive G/GEJ cancer receiving Tmab between March 2011 and January 2014 were enrolled. Data regarding the baseline characteristics before Tmab plus chemotherapy, pre-specified Tmab-related adverse events, and effectiveness were collected retrospectively. Treatment outcomes were estimated using Kaplan-Meier method and compared using log-rank test. Results: Of 181 enrolled pts, 179 were eligible for analysis and 123 received Tmab as first-line chemotherapy. ...