Jazz Pharmaceuticals has reported results from the second interim analysis of the Phase III HERIZON-GEA-01 trial evaluating Ziihera (zanidatamab-hrii) plus chemotherapy in adults receiving first-line treatment for human epidermal growth factor receptor 2 (HER2)-positive cancer.
Conducted jointly with BeOne Medicines, the open-label, global study randomised 914 patients across more than 30 countries at nearly 225 sites.
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The combination showed a statistically significant overall survival benefit compared with trastuzumab plus chemotherapy for HER2-positive, locally advanced or metastatic gastroesophageal adenocarcinoma (GEA).
The hazard ratio for overall survival with Ziihera plus chemotherapy improved versus the first interim analysis.
Furthermore, the safety profile of Ziihera administered with chemotherapy appeared consistent with previously reported data for each agent and the outcomes seen in the earlier stages of HERIZON-GEA-01.
No new safety concerns were identified as follow-up continued. Ziihera combined with Tevimbra (tislelizumab-jsgr) and chemotherapy also recorded an improved hazard ratio for overall survival compared with earlier analyses.
The US Food and Drug Administration (FDA) approved Ziihera along with tislelizumab and chemotherapy for first-line treatment in adults with HER2-positive (IHC 3+ and IHC 2+/ISH+) unresectable locally advanced or metastatic gastroesophageal adenocarcinoma (GEA) on 25 August 2026.
It also approved Ziihera in combination with chemotherapy for HER2-positive (IHC 3+) disease in the same setting.
Jazz Pharmaceuticals executive vice-president, research and development global head, and chief medical officer Rob Iannone said: “These results reinforce our confidence that Ziihera is the new HER2-targeted backbone therapy in first-line HER2+ advanced GEA, replacing trastuzumab and extending survival beyond the current standard of care.
“Following the recent FDA approval, and further supported by these updated results, we are moving quickly to establish Ziihera as the HER2-targeted, first-line therapy of choice, with Ziihera plus tislelizumab and chemotherapy as the new standard of care in the US.”
Jazz Pharmaceuticals has submitted data from the HERIZON-GEA-01 trial for presentation at a major medical meeting in the fourth quarter of 2026 and plans to submit these results to health authorities worldwide.
Patients with unresectable locally advanced, recurrent or metastatic HER2-positive GEA were assigned to receive zanidatamab with chemotherapy and tislelizumab, zanidatamab with chemotherapy, or trastuzumab plus chemotherapy.
The trial’s main endpoints were progression-free survival assessed by blinded independent central review and overall survival.
In August 2024, Jazz’s attempt to gain approval for its cannabidiol therapy in Japan encountered a setback when a Phase III trial conducted in the country did not achieve its primary endpoint.
