Ziihera (zanidatamab-hrii) approved on August 25, 2026 - its PDUFA goal date - for first-line HER2-positive advanced gastro-oesophageal adenocarcinoma, with and without tislelizumab plus chemotherapy.
Run-up into the decision (T-120 → T+5)
Daily close, T-120 (2/18/26) through T+0. Run-up high $261.62 on 8/4/26, low $168.72 on 2/18/26 (T-120 to T-1). FDA decision 8/25/26. Historical price action, not a forecast.
Key facts
FDA decision date2026-08-25
OutcomeApproved
Drug / candidateZiihera (zanidatamab-hrii)
IndicationFirst-line HER2-positive unresectable locally advanced or metastatic gastric, gastro-oesophageal junction and gastro-oesophageal adenocarcinoma, with and without tislelizumab plus chemotherapy
CompanyJazz Pharmaceuticals plc
Market-cap tierMid
120-day run-up (T-120→T-1)+52.0%
Cohort decision-day move (history)2.2% median (n=231)
The PDUFA target action date was August 25, 2026 and the FDA approved the supplemental BLA that day. The approval covers all HER2-positive patients (IHC 3+ and IHC 2+/ISH+) regardless of PD-L1 status. It rests on the Phase 3 HERIZON-GEA-01 trial, published in the New England Journal of Medicine and first presented at ASCO GI 2026: both Ziihera-containing combinations improved progression-free survival in the overall HER2-positive population, reducing the risk of progression or death by 35%, with median PFS of 12.4 months against 8.1 months for trastuzumab plus chemotherapy. This is zanidatamab's second FDA approval in under two years. Zanidatamab is partnered: Jazz holds the US application, and Zymeworks (ZYME) is entitled to a $250 million milestone payment on this approval.
Run-up figures are the stock's own daily closing path over the 120 trading days before the decision, from our price history. Cohort move is the historical median absolute decision-day move for this market-cap tier. History, not a prediction.
Was Ziihera (zanidatamab-hrii) approved by the FDA?
Yes. The FDA approved the application for Ziihera (zanidatamab-hrii) on August 25, 2026. The primary source is linked on this page.
Which company is behind Ziihera (zanidatamab-hrii)?
Ziihera (zanidatamab-hrii) is a Jazz Pharmaceuticals plc (JAZZ) program. The FDA decision came on August 25, 2026; the company's own announcement is linked on this page.
How did JAZZ stock trade into the FDA decision?
Measured over the 120 trading days before the decision (T-120 to T-1), JAZZ moved +52.0%. That is the recorded price path into this specific event -- historical measurement, not a prediction, and not investment advice.
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