SAN CARLOS, CALIF. -- BeOne Medicines Ltd. (Nasdaq: ONC; HKEX: 06160; SSE: 688235), a global oncology company, announced positive top-line results from the Phase 3 HERIZON-GEA-01 trial evaluating ZIIHERA® (zanidatamab), a HER2-targeted bispecific antibody, in combination with chemotherapy, with or without PD-1 inhibitor TEVIMBRA® (tislelizumab), as first-line treatment for HER2-positive (HER2+) locally advanced or metastatic gastroesophageal adenocarcinoma (GEA), including cancers of the stomach, gastroesophageal junction, and esophagus.

Both ZIIHERA plus TEVIMBRA and chemotherapy and ZIIHERA plus chemotherapy demonstrated clinically meaningful and highly statistically significant improvements in progression-free survival (PFS) compared to the control arm, trastuzumab plus chemotherapy.

ZIIHERA plus TEVIMBRA and chemotherapy also demonstrated clinically meaningful and statistically significant improvements in overall survival (OS), and ZIIHERA plus chemotherapy demonstrated a clinically meaningful effect with a strong trend toward statistical significance for OS compared to the control arm at the time of this first analysis. The trial is ongoing with an additional planned OS interim analysis for ZIIHERA plus chemotherapy currently expected in mid-2026.

These PFS and OS benefits were observed in the ZIIHERA plus TEVIMBRA and chemotherapy arm versus the control arm in both PD-L1 positive and PD-L1 negative subgroups. Supportive of the primary efficacy endpoints, both combination arms demonstrated improvements in the key secondary endpoints of objective response rate (ORR) and duration of response (DOR) versus the control arm.

“Gastric, gastroesophageal junction, and esophageal adenocarcinoma remain major global health challenges, particularly in advanced stages where outcomes are still poor,” said Dr. Sun Young Rha, Professor of Medical Oncology at the Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, South Korea, and investigator on the HERIZON-GEA-01 study. “The positive results of this trial demonstrate that zanidatamab-based combination regimens have the potential to reshape clinical practice for the first-line treatment of HER2-positive metastatic gastroesophageal disease.”

“These results represent meaningful progress for a patient community in urgent need of new treatment options. With the high incidence of GEA across many regions where we hold rights to ZIIHERA, we have the opportunity to deliver a major advancement for patients in an area of high unmet need,” said Mark Lanasa, M.D., Ph.D., Chief Medical Officer, Solid Tumors at BeOne. “This milestone underscores our dedication to advancing therapies for gastrointestinal cancers and demonstrates the potential of TEVIMBRA as an anti-PD-1 backbone in combination regimens. We look forward to collaborating with health authorities in our licensed territories, and to expanding TEVIMBRA’s label to include this combination.”

The safety profile of ZIIHERA in combination with chemotherapy, with and without TEVIMBRA, was generally consistent with the known safety profile of each agent with no new safety signals observed in the two investigational combination arms and supports the overall benefit-risk profile of ZIIHERA for use in this indication.

These data will be submitted for presentation at a major medical meeting in the first quarter of 2026.