Gastroesophageal adenocarcinoma presents the biggest market opportunity for Jazz Pharmaceuticals’ Ziihera, according to Truist Securities, which forecasts peak sales of the drug to reach $2.5 billion.
The FDA has given its blessing to Jazz Pharmaceuticals’ bispecific antibody Ziihera, allowing its use in newly diagnosed patients with gastroesophageal adenocarcinoma.
In particular, Ziihera is now indicated as a first-line treatment for patients with unresectable locally advanced or metastatic gastroesophageal adenocarcinoma (GEA) who harbor HER2 mutations, according to a Tuesday release. Ziihera is meant to be used with or without BeOne Medicines’ Tevimbra on top of chemotherapy.
Analysts at Truist Securities were unsurprised by the approval, calling the decision “anticipated” in a Tuesday note to investors. Still, the firm is encouraged by the verdict, saying that it “de-risks the largest piece of our Ziihera build for JAZZ.”
Ziihera was first approved in November 2024 for biliary tract cancer under the FDA’s accelerated pathway, but the GEA market represents around 90% of Truist’s peak $2.5 billion sales projection. “GEA is where the bulk of the franchise opportunity sits,” the analysts wrote said, adding that the company’s “setup for launch is favorable.”
Following Ziihera’s approval in what is likely its largest indication, investor focus has now shifted to the drug’s launch, which Truist anticipates to be “smooth sailing,” according to a follow-up note on Monday afternoon. “From our investor conversations and checks, Ziihera stands as the 1L preferred option in GEA off the approval.”
The firm nevertheless cautions that there “could be looming future threats,” pointing to regimens using AstraZeneca and Daiichi Sankyo’s Enhertu. The antibody-drug conjugate is currently indicated for the second-line treatment of HER2+ locally advanced or metastatic gastric cancer, and the companies are working to push the asset into the first-line setting.
For Ziihera, data from the Phase 3 HERIZON-GEA-01 trial supported the FDA’s approval on Tuesday. Results released in January showed a 35% reduction in the risk of disease progression or death in patients given Ziihera plus chemotherapy, as compared with the active control of trastuzumab plus chemotherapy. Adding Tevimbra to the Ziihera regimen slightly improved the treatment benefit to 37%.
Truist at the time called these findings “practice-changing.”
Jazz picked up rights to Ziihera from Canadian biotech Zymeworks before the drug secured U.S. approval. Jazz paid $50 million upfront, with different potential milestone fees down the line that could reach a deal total up to $1.76 billion. Under the terms of the deal, Jazz gained global rights to the drug across all indications, excluding certain Asia/Pacific areas previously licensed by Zymeworks.
