Zenidatamab for Injection (zanidatamab-hrii) - What is Ziihera?

Zenidatamab-hrii for injection (zanidatamab-hrii)-Ziihera is a bispecific HER2-directed antibody indicated for the treatment of HER2-positive biliary tract cancer, primarily for the treatment of adult patients with previously treated, unresectable or metastatic HER2-positive (IHC 3+) biliary tract cancer (BTC) as detected by a U.S. Food and Drug Administration (FDA)-approved trial. This indication received accelerated approval based on overall response rate and duration of response. Continued approval for this indication may be contingent upon verification and characterization of clinical benefit in confirmatory trials.

Biliary tract cancer consists of tumors derived from the epithelial cells of the biliary tract. Human epidermal growth factor receptor -2 (HER2) plays a key role in certain cancers, and HER2 is an established target for anti-tumor treatment of breast cancer and gastroesophageal adenocarcinoma. A growing body of literature suggests that HER2 is also associated with biliary tract cancer.

The main component of zenidatamab for injection, zanidatamab-hrii, plays a role in the treatment of HER2-positive BTC by binding to two extracellular sites on HER2, leading to the reduction of tumor cell surface receptors. zanidatamab-hrii induces complement-dependent cytotoxicity, antibody-dependent cytotoxicity, and antibody-dependent cellular phagocytosis, resulting in tumor growth inhibition and tumor cell death. The FDA’s accelerated approval of Ziihera is based on the results of the HERIZON-BTC-01 clinical trial, which demonstrated an objective response rate (ORR) of 52% and an estimated median duration of response (DOR) of 14.9 months.

Zenidatuzumab for injection is administered by intravenous infusion every two weeks. Premedication with acetaminophen, antihistamines, and corticosteroids 30-60 minutes before each infusion is recommended to prevent potential infusion-related reactions. Common adverse reactions (≥ 20%) include diarrhea, infusion-related reactions, abdominal pain, and fatigue.

Reference materials:https://www.drugs.com/history/ziihera.htm