Jazz's bispecific drug approved for biliary tract cancer

Jazz Pharmaceuticals has secured FDA approval for zanidatamab, a bispecific antibody targeting HER2, acquired from Zymeworks for an upfront payment of $50 million. The medication, branded as Ziihera, is set to be the pioneering drug in its category for biliary tract cancer patients. The company announced that it will be available within the next fortnight for patients who have previously undergone treatment and exhibit high HER2 expression according to an immunohistochemistry test.

CEO Bruce Cozadd refrained from disclosing Ziihera's pricing. He expressed the company's readiness to distribute the drug, supported by Jazz's established oncology sales team, as stated in his conversation with Endpoints News.

The FDA's accelerated approval of Ziihera was grounded on Phase 2b clinical data involving 87 biliary tract cancer patients, of which 62 showcased high HER2 expression. The drug demonstrated an objective response rate of 52%, with the median response duration being 14.9 months. Currently, a Phase 3 trial is in progress in the first-line setting, which the executives anticipate will back both a full approval for the second-line setting and a supplemental application for frontline patients.

Rob Iannone, Jazz's global head of R&D, expressed optimism about Ziihera's potential to become the standard of care in the frontline setting, contingent upon the trial's success. Although AstraZeneca and Daiichi Sankyo's Enhertu is accessible to biliary tract cancer patients through a tumor-agnostic approval, Iannone highlighted a possible advantage for Ziihera, emphasizing that a specific indication for biliary tract cancer provides more targeted data compared to a pan-tumor indication.

Iannone also highlighted Ziihera's safety profile, pointing out that it does not carry the potential safety risks associated with antibody-drug conjugates (ADCs). While Ziihera has a boxed warning for embryo-fetal toxicity, Iannone stressed that associated pregnancies during treatment are rare. The drug's label advises clinicians to inform patients about the risk and the necessity of effective contraception. There was one fatal incident of hepatic failure in a clinical trial participant treated with Ziihera, but Iannone noted that hepatic toxicity has not been a widespread issue. Only 2.5% of trial patients discontinued due to adverse reactions.

Jazz Pharmaceuticals remains hopeful that its 2022 deal with Zymeworks will yield further benefits as Ziihera advances in Phase 3 trials for gastroesophageal adenocarcinomas and metastatic breast cancer. Cozadd noted that since the agreement with Zymeworks, additional data has emerged supporting Ziihera's use in monotherapy, combination therapy, across various tumor types and treatment lines, thereby bolstering their confidence in the drug's broader applications.