The U.S. Food and Drug Administration (FDA) has granted accelerated approval to zanidatamab-hrii (Ziihera) for the treatment of adult patients with previously treated, unresectable, or metastatic HER2-positive biliary tract cancer (BTC). This approval marks a significant advancement in the treatment landscape for this aggressive cancer, providing a new chemotherapy-free option for patients who have progressed on prior therapies. The approval was announced by Jazz Pharmaceuticals, the developer of zanidatamab.
The approval is based on data from the phase 2b HERIZON-BTC-01 trial (NCT05152147), a multicenter, single-arm study that evaluated zanidatamab as a single agent in patients with HER2-amplified, unresectable, locally advanced, or metastatic BTC. The trial enrolled patients whose HER2-positive status was confirmed by an FDA-approved test.
HERIZON-BTC-01 Trial Results
The HERIZON-BTC-01 trial demonstrated clinically meaningful efficacy with zanidatamab monotherapy. According to an independent review committee (IRC) assessment, the objective response rate (ORR) was 41.3% (95% CI, 30.4%-52.8%). The median progression-free survival (PFS) was 5.5 months (95% CI, 3.7-7.2) per IRC evaluation and 5.4 months (95% CI, 3.6-7.2) based on investigator assessment.
Expert Commentary
"The approval of zanidatamab, 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 biliary tract cancer," said Rob Iannone, MD, MSCE, executive vice president, global head of research and development, and chief medical officer of Jazz Pharmaceuticals. "We look forward to advancing research of zanidatamab in biliary tract cancer and other HER2-expressing solid tumors, with the goal of improving outcomes for more people diagnosed with these difficult-to-treat HER2-positive cancers."
Zanidatamab: A Novel HER2-Targeted Bispecific Antibody
Zanidatamab is a novel HER2-targeted bispecific antibody that binds to two distinct epitopes of the HER2 receptor. This dual targeting mechanism allows for enhanced receptor clustering, internalization, and degradation, leading to potent anti-tumor activity. The drug is administered as a 50 mg/mL injection or intravenous infusion.
