Ziihera (zanidatamab-hrii) - (HERIZON-GEA-01)

Aug. 25, 2026: Jazz Pharmaceuticals plc (NASDAQ: JAZZ) said the FDA approved Ziihera (zanidatamab-hrii)-containing regimens for first-line treatment of adults with unresectable locally advanced or metastatic HER2-positive gastroesophageal adenocarcinoma. Approved uses are Ziihera plus tislelizumab-jsgr and fluoropyrimidine/platinum chemotherapy for HER2+ IHC 3+ and IHC 2+/ISH+ disease, and Ziihera plus fluoropyrimidine/platinum chemotherapy for HER2+ IHC 3+ disease.

The approval was based on the Phase 3 HERIZON-GEA-01 trial. In the overall HER2+ population, both Ziihera combinations improved progression-free survival, reducing risk of progression or death by 35% and extending median PFS to 12.4 months versus 8.1 months with trastuzumab plus chemotherapy. Ziihera plus tislelizumab and chemotherapy also showed a statistically significant overall survival benefit, reducing risk of death by 28% and improving median OS to 26.4 months versus 19.2 months. Benefits were described as generally consistent across major prespecified subgroups, including PD-L1 status.

The trial remains ongoing, with additional analyses planned. Results were published in NEJM, first presented at ASCO GI 2026, with PD-L1 subgroup data presented at ASCO 2026. Jazz will host an investor webcast on Aug. 25, 2026.