In today’s episode, we had the opportunity to speak with Arndt Vogel, MD, about the European Commission’s (EC's) July 2025 marketing authorization of zanidatamab-hrii (Ziihera) for the treatment of adult patients with previously treated, unresectable, locally advanced or metastatic HER2-positive biliary tract cancer. Dr Vogel is a faculty member at the University of Toronto Institute of Medical Science, a scientist at the Toronto General Hospital Research Institute, and a medical oncologist at the UHN–Princess Margaret Cancer Centre in Canada.

In our exclusive interview, Dr Vogel highlighted the clinical importance of this decision, emphasizing that it represents a significant advancement for a molecularly defined subgroup of patients with limited treatment options and historically poor outcomes. He explained that biliary tract cancers, including cholangiocarcinoma, are associated with high recurrence rates and poor survival, even in patients who undergo curative-intent surgery. For patients in the advanced setting, second-line chemotherapy offers modest clinical benefit, with objective response rates of approximately 6%, a median progression-free survival of approximately 3 months, and a median overall survival of approximately 12 months.

Vogel discussed the data supporting the EC’s approval, which was based on findings from the phase 2b HERIZON-BTC-01 trial (NCT04466891)—the largest study conducted to date evaluating HER2-directed therapy in this patient population. In the trial, at a median follow-up of 21.9 months, patients with centrally confirmed HER2-positive tumors (n = 80) who received zanidatamab achieved a confirmed objective response rate (cORR) of 41.3% (95% CI, 30.4-52.8). The median duration of response was 14.9 months (95% CI, 7.4-not reached), and the median overall survival reached 15.5 months (95% CI, 10.4-18.5).