Jazz Pharmaceuticals' Ziihera wins FDA priority review for first-line gastric cancer use
Jazz Pharmaceuticals has secured priority review from US regulators for an expanded use of its targeted cancer therapy Ziihera, advancing the Dublin-headquartered group's bid to establish the drug as a frontline standard of care in HER2-positive gastric and gastroesophageal cancers — one of the more commercially significant unmet needs in oncology.
The US Food and Drug Administration has accepted a supplemental biologics license application for Ziihera, known generically as zanidatamab-hrii, in combination with standard chemotherapy with or without tislelizumab — the PD-1 inhibitor marketed as Tevimbra by BeiGene — for the first-line treatment of adults with HER2-positive unresectable locally advanced or metastatic gastric, gastroesophageal junction or gastroesophageal adenocarcinoma. The agency has set a target action date under the Prescription Drug User Fee Act of 25 August 2026.
The filing rests on data from the phase 3 HERIZON-GEA-01 trial, which Jazz has positioned as practice-changing. According to the company, the study was the first phase 3 trial in metastatic GEA to demonstrate a median progression-free survival exceeding 12 months and a median overall survival exceeding 24 months. Investigators reported median overall survival of 26.4 months in the zanidatamab arm against 19.2 months in the comparator arm, a hazard ratio of 0.72. A further interim analysis of overall survival data is expected in mid-2026.
Rob Iannone, executive vice-president and chief medical officer at Jazz Pharmaceuticals, said the trial results supported "the potential of zanidatamab as the HER2-targeted agent of choice in HER2-positive first-line locally advanced or metastatic GEA", and that adding tislelizumab to the regimen further enhanced clinical benefit.
The commercial logic for Jazz is significant. Gastroesophageal adenocarcinoma — encompassing cancers of the stomach, gastroesophageal junction and oesophagus — is the fifth most common cancer worldwide, with roughly 20 per cent of patients carrying HER2-positive disease. Treatment options in the first-line metastatic setting have historically been limited, and the only approved HER2-targeted agent has been Roche's trastuzumab, the long-established backbone of HER2-positive therapy across multiple cancers. Securing approval in the front-line setting would position Ziihera to compete directly for a treatment market in which patient outcomes have remained stubbornly poor.
The FDA has already granted zanidatamab two breakthrough therapy designations and two fast track designations across its development programmes, alongside orphan drug status from both the FDA and the European Medicines Agency for biliary tract cancer, gastric and gastroesophageal cancers and oesophageal cancer. The drug is currently approved in the US for previously treated HER2-positive biliary tract cancer.
For Jazz, an expanded approval would mark the most significant inflection point yet for the asset, which the group acquired as part of its broader strategy to diversify beyond its established sleep and neuroscience franchises into oncology. Jazz shares closed at $196.52 last Friday, ahead of the Monday announcement.
The August PDUFA date positions Jazz for a potentially material revenue inflection in the second half of 2026, although the competitive backdrop is also intensifying. Several other companies are pursuing HER2-targeted therapies and antibody-drug conjugates in gastric cancer indications, with AstraZeneca and Daiichi Sankyo's Enhertu having already established meaningful traction in the second-line setting. The relative speed at which Jazz can convert a frontline approval into prescriber adoption, particularly given the entrenched position of trastuzumab, will be a key determinant of the asset's commercial trajectory.