Jazz Wins First-Line Ziihera Approval In Gastroesophageal Adenocarcinoma, Expanding Its Largest Franchise Opportunity

Jazz Pharmaceuticals has received FDA approval for Ziihera as a first-line treatment for patients with unresectable locally advanced or metastatic gastroesophageal adenocarcinoma who harbor HER2 mutations. The drug can be used with or without BeOne Medicines’ Tevimbra on top of chemotherapy, according to a Tuesday release cited by BioSpace.

The approval extends Ziihera beyond its November 2024 accelerated approval in biliary tract cancer and moves Jazz into what Truist Securities described as the largest piece of its commercial case for the asset. Truist said the decision was anticipated, but added that the outcome de-risks the biggest component of its Ziihera build for Jazz.

The data

FDA’s decision was supported by results from the Phase 3 HERIZON-GEA-01 trial. BioSpace reported that results released in January showed a 35% reduction in the risk of disease progression or death for patients treated with Ziihera plus chemotherapy versus trastuzumab plus chemotherapy as the active control.

Adding Tevimbra to the Ziihera regimen slightly improved that benefit to 37%, according to the same report. The approved regimen gives Jazz flexibility in how it positions the drug, while still tying the label to a biomarker-defined patient group rather than the broader HER2-positive gastric market.

The commercial picture

Truist projects the GEA market represents around 90% of its peak $2.5 billion sales estimate for Ziihera, making this approval more consequential than the earlier biliary tract cancer nod. The firm said investor attention has now shifted to launch performance and described the setup as favorable, adding in a follow-up note that Ziihera stands as the preferred first-line option in GEA based on its investor conversations and checks.

That said, the competitive window may not stay open indefinitely. Truist pointed to potential pressure from regimens built around AstraZeneca and Daiichi Sankyo’s Enhertu, which is already approved in the second-line setting for HER2+ locally advanced or metastatic gastric cancer and is being developed for first-line use.

Jazz obtained rights to Ziihera from Zymeworks for $50 million upfront in a deal that could reach up to $1.76 billion. The agreement gave Jazz global rights across all indications except certain Asia/Pacific areas that had already been licensed by Zymeworks.