The U.S. Food and Drug Administration (FDA) has approved Jazz Pharmaceuticals plc's Ziihera (zanidatamab-hrii) for the treatment of adult patients with previously treated, unresectable, or metastatic HER2-positive biliary tract cancer (BTC). This approval, granted on an accelerated basis, marks a significant milestone as Ziihera is the first dual HER2-targeted bispecific antibody specifically indicated for this patient population.
Clinical Significance
Biliary tract cancers are a group of rare and aggressive cancers that occur in the bile ducts and gallbladder. HER2 overexpression is observed in a subset of these cancers, making it a relevant therapeutic target. The approval of Ziihera offers a new treatment option for patients who have progressed on prior therapies and have limited alternatives. Ziihera is administered as an injection every two weeks.
Rob Iannone, Executive Vice President, Global Head of Research and Development, and Chief Medical Officer of Jazz Pharmaceuticals, stated that the approval of Ziihera, which previously received Breakthrough Therapy Designation from the FDA for this indication, is an important advance and offers the first and only dual HER2-targeted bispecific antibody and chemotherapy-free treatment for patients living with BTC.
Mechanism of Action and Ongoing Development
Zanidatamab, the active ingredient in Ziihera, is also being developed in clinical trials for other indications by Jazz and BeiGene, Ltd., under license agreements from Zymeworks, which first developed the molecule. This bispecific antibody is designed to bind to two different epitopes of the HER2 receptor, leading to HER2 receptor clustering, internalization, and degradation, ultimately inhibiting cancer cell growth.
Current Treatment Landscape
Prior to this approval, treatment options for HER2-positive biliary tract cancer included HER2-targeted therapies such as trastuzumab deruxtecan and trastuzumab, as well as checkpoint inhibitors like pembrolizumab. Ziihera provides an alternative approach with a potentially more favorable profile, offering a chemotherapy-free option for patients.
