Zanidatamab Combined With Chemotherapy as Neoadjuvant Therapy for HER2-high Expression G/GEJC

HER2 overexpression is observed in approximately 20% of gastric cancers and gastroesophageal junction (GEJ) cancers, making it a validated target for anti-tumor therapy . In advanced-stage systemic therapy, trastuzumab combined with chemotherapy has demonstrated clinical benefits for HER2-positive gastric and GEJ cancers . However, the combination of trastuzumab and pertuzumab plus chemotherapy did not significantly improve overall survival (OS) compared to trastuzumab monotherapy in HER2-expressed gastric/GEJ cancers .

In neoadjuvant therapy for early-stage or locally advanced gastric cancer, there is currently no standardized perioperative regimen for HER2-positive gastric or GEJ cancers, and effective treatment remains challenging .

Zanidatamab, a humanized bispecific IgG1-like antibody targeting HER2's ECD4 and ECD2 epitopes, exhibits unique enhanced functionality . Phase II studies (NCT03929666) showed that zanidatamab combined with chemotherapy as first-line therapy for HER2-positive advanced gastroesophageal adenocarcinoma (GEA) demonstrated superior survival benefits and durable responses compared to standard therapy (trastuzumab plus chemotherapy) . A Phase III study (HERIZON-GEA-01, NCT05152147) is now underway to further validate its efficacy when combined with chemotherapy ± tislelizumab versus trastuzumab-based chemotherapy .

For previously untreated stage II/III locally advanced gastroesophageal junction adenocarcinoma (cT1-2N+M0, cT3-4aNanyM0) with confirmed HER2 high expression (HER2 3+/2+ FISH+), neoadjuvant zanidatamab combined with chemotherapy (FLOT/SOX/CAPOX) is being explored to evaluate safety and efficacy, potentially offering a new treatment option for HER2-positive GEJ cancers in perioperative settings .