Dive Brief:
- The Food and Drug Administration has expanded use of Jazz Pharmaceuticals’ cancer treatment Ziihera, approving Tuesday the treatment as part of a new frontline regimen for HER2-positive gastrointestinal cancers.
- Jazz and partner Zymeworks — the drug’s original developer — first won an accelerated clearance for Ziihera in late-line biliary tract cancer in 2024. Use in that setting earned Jazz $24.8 million in revenue in 2025. The latest clearance opens up a market opportunity north of $1.5 billion, wrote RBC Capital Markets analyst Leonid Timashev, whose team expects “relatively quick uptake.”
- HER2-positive gastroesophageal cancers have long been treated with Roche’s Herceptin, an antibody drug that now faces biosimilar competition. In Jazz’s Phase 3 trial, combinations of Ziihera and chemotherapy with or without the immunotherapy Tevimbra reduced the risk of progression or death by 35% and the risk of death, specifically, by 28% when compared to Herceptin and chemo.
Dive Insight:
Jazz has two blockbuster drugs in its portfolio. Both are in neuroscience in the guise of the epilepsy drug Epidiolex and sleep medication Xywav. Jazz’s forays into oncology have proved less lucrative, as none of its other cancer drugs have become $1 billion-plus sellers.
Ziihera could be different. Around 12,000 people in the U.S. alone may now be eligible for treatment, substantially more than the 1,500 estimated to have the biliary tract cancer Ziihera is also cleared for, Stifel analyst Annabel Samimy wrote in a note to clients.
Samimy and RBC’s Timashev both noted that the FDA authorized broad use in people with lower levels of HER2 expression, even though the key study supporting Ziihera’s benefits had many more volunteers with high HER2 levels. The drug’s prescribing information also endorses use in tumors in the esophagus and the junction of the stomach and esophagus, even though most trial participants had cancer inside the stomach.
The FDA didn’t put many safety limits on the drug, either, the analysts wrote. A warning about severe diarrhea was added to the drug’s label because it occurred so often, but may have been included to get patients to adhere to anti-diarrheal treatment while undergoing Ziihera therapy, Samimy wrote. Her team forecasted $650 million to $700 million in U.S. sales related to gastroesophageal cancers.
Ziihera’s revenue potential could climb higher still if it’s successful in breast cancer. Jazz is testing Ziihera in a number of settings for breast tumors. Data from the first of those studies could emerge in late 2027.
Jazz acquired most rights to Ziihera through a 2022 deal with Zymeworks. Following the positive results in gastrointestinal cancer last year, Zymeworks changed course to focus on deriving revenue from drug royalties rather than by selling its own medicines. It earned a $250 million payment for the latest approval, and stands to receive another $1.3 billion in milestones, plus royalties, from the collaboration.
Zymeworks also banked an $81 million payment from BeOne Medicines, which owns rights to Ziihera in Asia, Australia and New Zealand.
Facts Only
* The Food and Drug Administration approved the expanded use of Jazz Pharmaceuticals’ cancer treatment Ziihera as part of a new frontline regimen for HER2-positive gastrointestinal cancers on Tuesday.
* Jazz and partner Zymeworks obtained accelerated clearance for Ziihera in late-line biliary tract cancer in 2024, generating $24.8 million in revenue for Jazz in 2025 in that setting.
* The latest clearance opens up a market opportunity north of $1.5 billion.
* In a Phase 3 trial, combinations of Ziihera and chemotherapy with or without immunotherapy Tevimbra reduced the risk of progression or death by 35% and the risk of death by 28% compared to Herceptin and chemo.
* Jazz has two other portfolio drugs in neuroscience: Epidiolex (epilepsy) and Xywav (sleep medication).
* The FDA authorized broad use in people with lower levels of HER2 expression, despite key studies involving high HER2 levels.
* Prescribing information endorses use in tumors in the esophagus and the junction of the stomach and esophagus.
* A warning about severe diarrhea was added to the drug’s label due to its frequent occurrence.
* Forecasted U.S. sales related to gastroesophageal cancers are estimated between $650 million and $700 million.
* Jazz acquired most rights to Ziihera through a 2022 deal with Zymeworks, involving payments and milestone agreements.
Executive Summary
Full Take
The narrative presents a tension between established therapeutic uses and emergent market potential. The expansion of Ziihera into gastroesophageal cancers relies on extrapolating benefits from prior data, specifically acknowledging that the key efficacy study involved patients with high HER2 expression while the new authorization permits use in lower expression groups. This dynamic raises questions about whether broad regulatory approval translates directly to equitable clinical utility across diverse patient populations and anatomical sites, particularly given that prescribing information addresses indications (esophagus/stomach junction) that may differ from trial participant locations.
The structure reveals a strategic pivot by Zymeworks toward royalty streams following the initial success, suggesting an evolution where revenue generation is decoupled from direct drug sales. Furthermore, the portfolio contrast—where neuroscience drugs are established blockbusters and oncology ventures have yielded less significant revenue—points to an asymmetric risk/reward profile in the pharmaceutical sector. The potential for higher revenue hinges on successful penetration into areas outside initial trial populations, such as breast cancer, suggesting a reliance on future pipeline data to validate current market estimations rather than solely existing approvals.
The persistent focus on safety signaling, exemplified by adding a note about diarrhea, alongside the large forecasted sales figures, suggests that managing patient adherence and side effects is an intrinsic part of realizing the projected market value. The systemic implication concerns how regulatory frameworks balance the need for rapid market access against ensuring that expanded indications maintain rigorous evidence standards. What controls are in place to ensure that expanding use based on lower HER2 expression does not introduce unforeseen risks or create disparities in treatment access? What is the long-term relationship between royalty agreements and sustained innovation post-licensing?
Sentinel — Human
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