Zanidatamab, sold under the brand name Ziihera, is a

humanized monoclonal antibody Humanized antibodies are antibodies from non-human species whose protein sequences have been modified to increase their similarity to antibody variants produced naturally in humans. The process of "humanization" is usually applied to monoclonal ant ...

used for the treatment of HER2-positive

biliary tract cancer Cholangiocarcinoma, also known as bile duct cancer, is a type of cancer that forms in the bile ducts. Symptoms of cholangiocarcinoma may include abdominal pain, yellowish skin, weight loss, generalized itching, and fever. Light colored stoo ...

. It is an IgG-like bispecific HER2-directed antibody directed against two non-overlapping domains of HER2. Zanidatamab is produced in

Chinese hamster ovary cell Chinese hamster ovary (CHO) cells are a family of immortalized cell lines derived from epithelial cells of the ovary of the Chinese hamster, often used in biological and medical research and commercially in the production of recombinant therap ...

s. The most common adverse reactions include

diarrhea Diarrhea (American English), also spelled diarrhoea or diarrhœa (British English), is the condition of having at least three loose, liquid, or watery bowel movements in a day. It often lasts for a few days and can result in dehydration d ...

infusion-related reaction In immunology, cytokine release syndrome (CRS) is a form of systemic inflammatory response syndrome (SIRS) that can be triggered by a variety of factors such as infections and certain drugs. It refers to cytokine storm syndromes (CSS) and occurs ...

abdominal pain Abdominal pain, also known as a stomach ache, is a symptom associated with both non-serious and serious medical issues. Since the abdomen contains most of the body's vital organs, it can be an indicator of a wide variety of diseases. Given th ...

, and

fatigue Fatigue is a state of tiredness (which is not sleepiness), exhaustion or loss of energy. It is a signs and symptoms, symptom of any of various diseases; it is not a disease in itself. Fatigue (in the medical sense) is sometimes associated wit ...

. Zanidatamab was approved for medical use in the United States in November 2024. The US

Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respo ...

(FDA) considers it to be a

first-in-class medication A first-in-class medication is a prototype drug that uses a "new and unique mechanism of action" to treat a particular medical condition. While the Food and Drug Administration's Center for Drug Evaluation and Research tracks first-in-class medic ...

Medical uses

Zanidatamabis

indicated In medicine, an indication is a valid reason to use a certain test, medication, procedure, or surgery. There can be multiple indications to use a procedure or medication. An indication can commonly be confused with the term diagnosis. A diagnosis ...

for the treatment of adults with previously treated, unresectable or

metastatic Metastasis is a pathogenic agent's spreading from an initial or primary site to a different or secondary site within the host's body; the term is typically used when referring to metastasis by a cancerous tumor. The newly pathological sites, ...

HER2-positive (IHC 3+)

, as detected by an FDA-approved test.

Adverse effects

The US

prescribing information contains a

boxed warning In the United States, a boxed warning (sometimes "black box warning", colloquially) is a type of warning that appears near the beginning of the package insert for certain prescription drugs, so called because the U.S. Food and Drug Administratio ...

for embryo-fetal toxicity. The most common adverse reactions include diarrhea, infusion-related reactions, abdominal pain, and fatigue.

History

Efficacy was evaluated in HERIZON-BTC-01 (NCT04466891), an open-label multicenter, single-arm trial in 62 participants with unresectable or metastatic HER2-positive (IHC3+)

. Participants were required to have received at least one prior

gemcitabine Gemcitabine, sold under the brand name Gemzar, among others, is a chemotherapy medication used to treat cancers. It is used to treat testicular cancer, breast cancer, ovarian cancer, non-small cell lung cancer, pancreatic cancer, and bladder ca ...

-containing regimen in the advanced disease setting. The US

(FDA) granted the application for zanidatamab

priority review Priority review is a program of the United States Food and Drug Administration (FDA) to expedite the review process for drugs that are expected to have a particularly great impact on the treatment of a disease. The priority review voucher program ...

breakthrough therapy Breakthrough therapy is a United States Food and Drug Administration designation that expedites drug development that was created by Congress under Section 902 of the 9 July 2012 Food and Drug Administration Safety and Innovation Act. The FDA's "b ...

, and

orphan drug An orphan drug is a medication, pharmaceutical agent that is developed to treat certain rare medical conditions. An orphan drug would not be profitable to produce without government assistance, due to the small population of patients affected by th ...

designations.

Society and culture

Legal status

Zanidatamab was approved for medical use in the United States in November 2024. In April 2025, the

Committee for Medicinal Products for Human Use The Committee for Medicinal Products for Human Use (CHMP), formerly known as the Committee for Proprietary Medicinal Products (CPMP), is the European Medicines Agency's committee responsible for elaborating the agency's opinions on all issues regar ...

of the

European Medicines Agency The European Medicines Agency (EMA) is an agency of the European Union (EU) in charge of the evaluation and supervision of pharmaceutical products. Prior to 2004, it was known as the European Agency for the Evaluation of Medicinal Products ...

adopted a positive opinion, recommending the granting of a conditional marketing authorization for the medicinal product Ziihera, intended for the treatment of adults with unresectable locally advanced or metastatic HER2-positive biliary tract cancer. The applicant for this medicinal product is Jazz Pharmaceuticals Ireland Limited. Text was copied from this source which is copyright European Medicines Agency. Reproduction is authorized provided the source is acknowledged. Zanidatamab was authorized for medical use in the European Union in June 2025.

Names

Zanidatamab is the international nonproprietary name. Zanidatamab is sold under the brand name Ziihera.

References

External links

* * * {{Authority control Antineoplastic drugs Monoclonal antibodies for tumors Orphan drugs