Jazz Pharma Drug Sets Survival Record in Stomach Cancer Trial
Ziihera (zanidatamab) shows a 28% reduction in death risk, with median survival extending beyond two years, positioning it as a potential new standard of care.
Jazz Pharmaceuticals PLC (NASDAQ: JAZZ) announced groundbreaking results from a late-stage trial for its cancer therapy Ziihera (zanidatamab), which demonstrated the longest median overall survival ever reported in a Phase 3 study for patients with a specific type of advanced or metastatic stomach cancer.
The HERIZON-GEA-01 trial evaluated Ziihera in patients with HER2-positive gastroesophageal adenocarcinoma (GEA). The combination of Ziihera with chemotherapy and the immunotherapy drug tislelizumab achieved a median overall survival of 26.4 months. This represents a more than seven-month improvement over the current standard of care, trastuzumab plus chemotherapy, and translated to a 28% reduction in the risk of death, according to the company's official announcement.
The results were hailed as a significant clinical advancement. “Reaching more than two years of median overall survival in a global Phase 3 trial for HER2+ metastatic GEA is truly unprecedented,” said Dr. Elena Elimova of the Princess Margaret Cancer Centre, who presented the findings. “These findings signal a meaningful step forward for patients who have historically faced very limited long-term outcomes.”
Shares of Jazz Pharmaceuticals showed modest movement in Tuesday trading, closing up 1.8% at $170.05. The muted reaction reflects a nuanced view of the detailed data, where a combination of Ziihera with chemotherapy alone—without the added immunotherapy—also showed a strong survival trend, though it did not yet reach statistical significance at this interim analysis. Some analysts suggested the market was weighing the incremental benefit of the three-drug cocktail against the doublet, but the overall sentiment remains highly positive on the drug's future.
Analysts at RBC Capital reiterated an "Outperform" rating, viewing the results as a "clear evolution beyond the current standards" that positions Ziihera to become the new foundation of care in this setting. The consensus 12-month price target for Jazz stock sits at $213.00, reflecting optimism in the company's oncology pipeline.
The trial data also showed a significant improvement in progression-free survival (PFS), with both Ziihera-based regimens reducing the risk of disease progression or death by approximately 35% compared to the control arm. The median duration of response for the Ziihera-tislelizumab combination was 20.7 months, more than double the 8.3 months seen in the standard-care arm.
Dr. Geoffrey Ku, a study co-author from Memorial Sloan Kettering Cancer Center, labeled the results as “practice-changing.” He added that “zanidatamab plus chemotherapy, with or without tislelizumab, should become the new standard of care for patients with HER2+ first-line locally advanced unresectable or metastatic GEA.”
For Jazz Pharmaceuticals, a Dublin-based company with a market capitalization of over $10 billion, the success of Ziihera is a crucial step in solidifying its position in the competitive oncology market. The company has built a diverse portfolio focused on neurology and cancer, and Ziihera is now poised to become a cornerstone of its oncology franchise.
“The strength of the HERIZON-GEA-01 data firmly positions Ziihera as the HER2-targeted agent-of-choice capable of reshaping first-line treatment for HER2+ metastatic GEA patients,” said Dr. Rob Iannone, executive vice president and global head of R&D at Jazz Pharmaceuticals. “These results signal a clear evolution beyond the current standards and give us strong conviction as we move rapidly toward FDA submission.”
The company confirmed it plans to submit the drug for approval to the U.S. Food and Drug Administration (FDA) in the first half of 2026. Ziihera has already received Breakthrough Therapy and Fast Track designations from the FDA for related indications, which could expedite its review process and path to market.