Ziihera (zanidatamab-hrii) was approved by the FDA on August 25, 2026 for first-line HER2-positive gastroesophageal adenocarcinoma (GEA).
Ziihera (zanidatamab-hrii), partnered to Jazz, approved on August 25, 2026 for first-line HER2-positive advanced gastro-oesophageal adenocarcinoma - triggering a $250 million milestone to Zymeworks.
The PDUFA target action date was August 25, 2026 and the FDA approved the supplemental BLA that day. Zanidatamab originated at Zymeworks and is partnered to Jazz Pharmaceuticals, which holds the US application; this listing exists because the approval is material to Zymeworks, which is entitled to a $250 million milestone payment on it. The approval covers all HER2-positive patients (IHC 3+ and IHC 2+/ISH+) regardless of PD-L1 status, based on the Phase 3 HERIZON-GEA-01 trial: median progression-free survival of 12.4 months against 8.1 months for trastuzumab plus chemotherapy, a 35% reduction in the risk of progression or death.
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.
Primary source: Jazz Pharmaceuticals / Zymeworks announcement, August 25, 2026
FDA record of the action: the FDA approved on August 25, 2026, per BLA 761416 S-003 (FDA letter). The sponsor announced it the same day. Action dates on pdufa.bio come from the FDA's own record, not the press release. Every FDA action we hold, by FDA date: FDA approval letters.
| Fund | Shares | Value at quarter end | Filing |
|---|---|---|---|
| EcoR1 Capital | 22,970,388 | $600.4 million | filed August 14, 2026 |
| Perceptive Advisors | 4,182,953 | $109.3 million | filed August 14, 2026 |
| BVF Inc. | 3,649,142 | $95.4 million | filed August 14, 2026 |
| Redmile Group | 491,654 | $12.9 million | filed August 14, 2026 |
13F reports list long positions in common stock at quarter end, are due 45 days later, and show no short positions or later trades. Notes, warrants and other instruments are not counted as shares.
Yes. The FDA approved the application for Ziihera (zanidatamab-hrii) on August 25, 2026, per the FDA's own record. The primary source is linked on this page.
Ziihera (zanidatamab-hrii) is a Zymeworks Inc. (ZYME) program. The FDA decision came on August 25, 2026; the company's own announcement is linked on this page.
Measured over the 120 trading days before the decision (T-120 to T-1), ZYME moved +5.5%. That is the recorded price path into this specific event. Historical measurement, not a prediction, and not investment advice.