Don Tracy, Associate Editor

Submission for the FDA approval of zanidatamab was based on promising data from the Phase IIb HERIZON-BTC-01 clinical trial in patients with previously treated, unresectable, locally advanced, or metastatic HER2-positive biliary tract cancer.
Jazz Pharmaceuticals announced that the FDA has granted Priority Review to zanidatamab, a bispecific antibody being evaluated for previously treated, unresectable, locally advanced, or metastatic HER2-positive biliary tract cancer (BTC). According to the company, the submission was based on positive results from Cohort 1 of the Phase IIb HERIZON-BTC-01 clinical trial, which showed a confirmed objective response rate (cORR) of 41.3%. The FDA assigned the application with a Prescription Drug User Fee Act target action date of November 29, 2024.
A Phase III trial, HERIZON-BTC-302, is evaluating zanidatamab in combination with standard-of-care therapy against standard-of-care therapy alone in first-line advanced or metastatic HER2-positive BTC.1
"The priority review designation for zanidatamab underscores the critical need for new treatment options for patients with locally advanced or metastatic HER2-positive BTC, a devastating disease with a poor prognosis,” said Rob Iannone, MD, MSCE, EVP, global head of research and development, Jazz Pharmaceuticals, in a press release. "Upon approval, zanidatamab will be the first HER2-targeted treatment specifically indicated for these patients, and we look forward to the opportunity to deliver this new treatment option to the BTC community."
In April, Jazz submitted a Biologics License Application (BLA) to the FDA for accelerated approval of zanidatamab. The BLA included data from the Phase IIb HERIZON-BTC-01 trial, demonstrating the cORR from Cohort 1, with an estimated median duration of response of 12.9 months [95% CI: 6.0-not estimable]. Previously, response rates for chemotherapy in patients with BTC were anywhere from 5% to 15%.2,3
"This important milestone brings us one step closer to delivering zanidatamab, a targeted treatment option, to patients living with HER2-positive BTC, a type of cancer that is associated with a five-year overall survival rate of less than 5%," said Iannone, in a press release. "Zanidatamab is a biparatopic HER2-targeted bispecific antibody that simultaneously binds two non-overlapping epitopes of HER2 resulting in multiple mechanisms of action. Second-line (2L) BTC represents the first of multiple indications we are evaluating and we are excited about zanidatamab's potential as a new option for multiple HER2-expressing cancers, with ongoing Phase III trials in 1L BTC, 1L gastroesophageal adenocarcinoma, and previously treated breast cancer."
According to the American Cancer Society, bile duct cancers are difficult to diagnose, with an estimated 8,000 US citizens receiving a diagnosis each year. However, the number could possibly be higher due to the challenges with diagnosis. Chances for survival depend on the patient’s age, the stage of the cancer when found, and its precise location.4
“Bile duct cancer is seen mainly in older people, but it can occur in younger people,” reports the American Cancer Society. “The average age of people in the US diagnosed with cancer of the intrahepatic (inside the liver) bile ducts is 70, and for cancer of the extrahepatic (outside the liver) bile ducts it's 72.”