FDA expands Jazz's Ziihera to frontline HER2-positive gastroesophageal cancers, unlocking $1.5 billion market

The U.S. Food and Drug Administration has broadened the approved use of Jazz Pharmaceuticals' cancer therapy Ziihera. The drug can now be given as an initial treatment for patients with HER2‑positive gastroesophageal adenocarcinomas.

Jazz first received accelerated clearance for Ziihera in 2024 for late‑line biliary tract cancer, generating about $24.8 million in revenue last year. The new indication moves the drug into a much larger patient population.

Analysts estimate the expanded market could be worth more than $1.5 billion, with rapid uptake expected. In a Phase 3 trial, Ziihera combined with chemotherapy, with or without the immunotherapy Tevimbra, cut the risk of disease progression or death by 35% and reduced overall mortality by 28% compared with the standard Herceptin‑based regimen.

Herceptin, Roche's long‑standing HER2‑targeted antibody, now faces biosimilar competition, and Ziihera's entry may shift treatment patterns in this space.