Jazz Pharmaceuticals plc announced that the European Commission (EC) has granted conditional marketing authorization for Ziihera® (zanidatamab), a dual HER2-targeted bispecific antibody, as monotherapy for adults with unresectable locally advanced or metastatic HER2-positive biliary tract cancer (BTC) who have received at least one prior systemic therapy.
Biliary tract cancers, which include gallbladder cancer and cholangiocarcinoma, are rare and aggressive cancers often diagnosed at advanced stages when surgery is no longer an option. Approximately 26% of BTC patients have HER2-positive tumors, a marker linked to poorer outcomes.
Ziihera is the first HER2-targeted therapy to receive conditional approval in the EU for this indication. Continued approval depends on results from the ongoing Phase 3 HERIZON-BTC-302 trial evaluating zanidatamab combined with standard care versus standard care alone in first-line treatment for HER2-positive BTC.
The EC decision is based on data from the Phase 2b HERIZON-BTC-01 trial—the largest of its kind in this patient population—which showed a confirmed objective response rate (cORR) of 41.3% with zanidatamab monotherapy. In patients with IHC 3+ tumors, the cORR rose to 51.6%. Median duration of response was 14.9 months, and median overall survival was 15.5 months, increasing to 18.1 months in the IHC 3+ subgroup.
Common side effects reported included diarrhea, infusion-related reactions, abdominal pain, anemia, and fatigue, with serious adverse events in 16.1% of patients.
“This conditional approval is a major step forward for patients with advanced HER2-positive BTC, who previously had limited treatment options,” said Robert Iannone, Jazz Pharmaceuticals’ chief medical officer. “Ziihera offers a targeted therapy option with promising efficacy and a manageable safety profile.”
The authorization covers all EU member states as well as Iceland, Norway, and Liechtenstein.
Patient advocacy groups welcomed the news, highlighting the urgent need for effective therapies in this challenging cancer type.
Jazz Pharmaceuticals is actively recruiting patients for its global Phase 3 trial and continues to explore zanidatamab’s potential in other HER2-expressing tumors.