Zanidatamab Approved for HER2+ Biliary Tract Cancer

Key Insights

• The FDA granted accelerated approval to zanidatamab for previously treated, unresectable or metastatic HER2-positive biliary tract cancer.
• Zanidatamab, a dual HER2-targeted bispecific antibody, achieved a 52% overall response rate in the HERIZON-BTC-01 trial.
• The estimated duration of response to zanidatamab was 14.9 months, offering a chemotherapy-free option for this patient population.

The FDA has granted accelerated approval to zanidatamab-hrii (Ziihera) for adult patients with previously treated, unresectable or metastatic HER2-positive biliary tract cancer, as detected by an FDA-approved test. This regulatory decision is based on findings from the phase 2b HERIZON-BTC-01 trial (NCT04466891).

HERIZON-BTC-01 Trial Results

The HERIZON-BTC-01 trial evaluated zanidatamab in 62 patients with HER2-positive biliary tract cancer. The agent elicited an overall response rate of 52% (95% CI, 39%-65%). The estimated duration of response was 14.9 months (95% CI, 7.4-not estimable).

Significance of Approval

This approval marks zanidatamab as the first and only dual HER2-targeted bispecific antibody and chemotherapy-free treatment option for this patient population. Biliary tract cancer is often diagnosed at advanced stages, and treatment options are limited, highlighting the importance of new therapies like zanidatamab.