Zanidatamab May Confer Improved Treatment Responses in Biliary Tract Cancers With HER2 Expressions

Zanidatamab, a HER2-targeted bispecific antibody, as monotherapy demonstrated positive results for patients with previously treated biliary tract cancer with HER2 expressions, according to recent data from a phase 2 clinical trial.

Specifically, 41.3% of patients achieved an objective response rate (the rate of a measurable response to the treatment). The median duration of response (the time it takes for the disease to respond to treatment without growth or spread) was 12.9 months. Additionally, the safety profile with zanidatamab in this trial was consistent with what has been previously observed and no new side effects were identified.

"We are thrilled to report these positive topline data from the HERIZON-BTC-01 clinical trial, which further support the potential of zanidatamab as a new chemotherapy-free therapeutic option for HER2-amplified and expressing (biliary tract cancer),” said Dr. Neil Josephson, chief medical officer at Zymeworks, the drug’s manufacturer, in a press release. “These data demonstrate that zanidatamab, as a single agent, improves on the current standard of care for patients in a difficult-to-treat disease who currently have a poor prognosis based on the limited treatment options currently available."

Of note, biliary tract cancers include gallbladder and cholangiocarcinoma and are diagnosed in more than 210,000 people every year, according to the release, with most presenting an inoperable disease. Additionally, the HER2 target is promising, presenting in 5% to 10% of cholangiocarcinomas and 20% of gallbladder cancers. However, there are currently no HER2-targeted therapies approved for this population; if approved by the Food and Drug Administration, zanidatamab could be the first of its kind.

"Through our work with the (biliary tract cancer) patient community, we see first-hand the challenge these patients face in not only getting a diagnosis but in the limited treatment options available," said Stacie Lindsey, founder and CEO of the Cholangiocarcinoma Foundation, in the release. "Each investigative trial begins to close the gap on this high unmet medical need by helping to bring more treatment options to (biliary tract cancer) patients"

Further results from the study are expected to be presented at a medical meeting in 2023, according to the release.

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