BeOne Reports Long-Term Survival Benefit in HER2+ GEA Cancer

San Carlos, California, U.S., October 23, 2026

HERIZON-GEA-01 Shows Sustained Overall Survival

The updated analysis followed patients for a median of 35.3 months, providing an additional 9.4 months of follow-up compared with the first interim analysis. In the TEVIMBRA plus ZIIHERA and chemotherapy group, median overall survival reached 27.0 months, with a hazard ratio of 0.65 compared with trastuzumab plus chemotherapy. ZIIHERA plus chemotherapy also demonstrated a statistically significant overall survival improvement over trastuzumab plus chemotherapy, with median survival of 22.9 months versus 19.6 months and a hazard ratio of 0.76. This result met the remaining primary endpoint analysis reported for the study. When TEVIMBRA was added to ZIIHERA and chemotherapy, median overall survival was four months longer than with ZIIHERA plus chemotherapy alone. However, this direct comparison did not reach statistical significance in the reported analysis (p=0.0502), which the company described as underpowered. These distinctions are important when interpreting the findings: the data support the benefit of the combination against the trastuzumab-based control, while the incremental benefit of adding TEVIMBRA to the ZIIHERA regimen remains less conclusive.

Combination Therapy Improves Progression-Free Survival

The trial also assessed progression-free survival (PFS), which measures the time patients live without their disease worsening or death. Median PFS was 12.7 months for TEVIMBRA plus ZIIHERA and chemotherapy, compared with 8.3 months for trastuzumab plus chemotherapy. The hazard ratio was 0.61, indicating a lower risk of progression or death in the combination group. ZIIHERA plus chemotherapy achieved median PFS of 12.4 months, compared with 8.3 months for trastuzumab plus chemotherapy. The estimated three-year overall survival rates further highlighted the differences between treatment groups: 39.8% for the TEVIMBRA-containing regimen, 31.5% for ZIIHERA plus chemotherapy and 22.9% for trastuzumab plus chemotherapy. A trend toward improved overall survival with the TEVIMBRA-containing regimen was also observed across PD-L1 expression subgroups. No new safety signals were identified in the updated analysis. Diarrhoea was the most common Grade 3 or higher treatment-related adverse event, and anti-diarrhoeal prophylaxis was implemented during the first treatment cycle because many cases occurred early in therapy.

BeOne Advances Targeted and Immunotherapy-Based Cancer Care

The HERIZON-GEA-01 study enrolled 914 patients across approximately 300 sites in more than 30 countries. It evaluated three first-line treatment approaches for adults with unresectable locally advanced, recurrent or metastatic HER2-positive gastroesophageal adenocarcinoma, including cancers of the stomach, oesophagus and gastroesophageal junction. ZIIHERA, or zanidatamab, is a bispecific antibody targeting HER2, designed to bind two extracellular sites on the receptor and promote antitumour activity. TEVIMBRA, or tislelizumab, is a PD-1 immune checkpoint inhibitor intended to help the immune system recognize and attack cancer cells. Combining targeted HER2 therapy, immunotherapy and chemotherapy aims to address cancer through complementary mechanisms. BeOne announced that the U.S. FDA approved the TEVIMBRA-based combination regimen in August 2026 for eligible first-line HER2-positive advanced gastroesophageal adenocarcinoma. The updated trial findings strengthen the evidence supporting this treatment approach, while ongoing clinical assessment remains important for understanding its benefits and risks across patient groups. The results represent a significant development in first-line HER2-positive GEA treatment, particularly given the sustained survival observed with the combination regimen.

Source: BeOne Medicines press release