Jazz Pharmaceuticals plc said Tuesday the U.S. Food and Drug Administration approved two Ziihera-based regimens for previously untreated adults with unresectable locally advanced or metastatic HER2-positive gastroesophageal adenocarcinoma.
The approval covers two regimens: Ziihera (zanidatamab-hrii) combined with Tevimbra (tislelizumab-jsgr) and fluoropyrimidine- and platinum-containing chemotherapy, and Ziihera plus the same chemotherapy backbone alone. Both are indicated for patients with HER2-positive disease, with the dual-agent regimen restricted to those with IHC 3+ or IHC 2+/ISH+ status.
The decision follows results from the Phase 3 HERIZON-GEA-01 trial, which showed both Ziihera-containing combinations significantly improved efficacy versus the standard trastuzumab plus chemotherapy. The regimens reduced the risk of disease progression or death by 35%, extending median progression-free survival to 12.4 months from 8.1 months. The Ziihera-Tevimbra-chemotherapy combination also cut the risk of death by 28%, raising median overall survival to 26.4 months versus 19.2 months in the comparator arm.
Gastroesophageal adenocarcinoma ranks as the fifth most common cancer globally, with roughly one in five cases classified as HER2-positive. In the United States alone, more than 31,000 new stomach cancer cases are diagnosed annually, underscoring the unmet need in this patient population.
The prescribing information for Ziihera includes boxed warnings for diarrhea and embryo-fetal toxicity. Diarrhea occurred in 85% of patients receiving the triple combination, including Grade 3 or 4 events in 26%, and was associated with fatal outcomes in 1.5% of cases. Jazz Pharmaceuticals said it will host an investor webcast at 4:30 p.m. ET Tuesday to discuss the approval and next steps.
