Jazz Pharmaceuticals plc (NASDAQ:JAZZ) today announced second interim top-line overall survival (OS) results from the Phase 3 HERIZON-GEA-01 trial showing that Ziihera® (zanidatamab-hrii) in combination with chemotherapy demonstrated statistically significant and clinically meaningful improvements in OS compared with trastuzumab plus chemotherapy as first-line treatment for adults with HER2-positive (HER2+) locally advanced or metastatic gastroesophageal adenocarcinoma (GEA). The Ziihera plus chemotherapy OS hazard ratio improved compared with the first interim analysis.

"Advanced HER2+ GEA remains an aggressive cancer with a poor prognosis, and trastuzumab plus chemotherapy has anchored first-line treatment for years. These HERIZON-GEA-01 results show that Ziihera-based regimens extend OS, demonstrating definitive superiority of Ziihera over trastuzumab and setting a new benchmark for what a first-line HER2-targeted therapy can achieve," said Dr. Kohei Shitara, director of the Department of Gastrointestinal Oncology, and principal trial investigator at the National Cancer Center Hospital East, Kashiwa, Japan.