Ziihera (zanidatamab-hrii) is a novel targeted therapy granted accelerated approval by the U.S. FDA, specifically indicated for the treatment of certain types of biliary tract cancers. As a significant advancement in the field of biologics, its unique pharmaceutical properties, strict storage requirements, and precise clinical application standards exemplify modern targeted cancer therapy.

What Is Ziihera (Zanidatamab-hrii)?

Pharmacological Action

Ziihera is a humanized IgG-like bispecific HER2-directed antibody produced in Chinese Hamster Ovary (CHO) cells using recombinant DNA technology.

With a molecular weight of approximately 124.8 kDa, it showcases the precision of modern biotechnology.

The drug simultaneously binds to two extracellular epitopes of the HER2 receptor, triggering receptor internalization and thereby reducing the number of receptors on the tumor cell surface.

It induces complement-dependent cytotoxicity (CDC), antibody-dependent cellular cytotoxicity (ADCC), and antibody-dependent cellular phagocytosis (ADCP). These synergistic mechanisms collectively inhibit tumor growth and induce cell death.

Clinical Indications

This medication is specifically indicated for the treatment of adult patients with previously treated, unresectable or metastatic HER2-positive (IHC 3+) biliary tract cancer (BTC).

The approval of this indication is based on robust evidence of overall response rate and duration of response, reflecting the in-depth application of precision medicine in cancer treatment.

Dosage Form, Specification, and Properties of Ziihera (Zanidatamab-hrii)

Formulation and Specification

Ziihera is supplied as a sterile, preservative-free white lyophilized powder.

Each single-dose vial contains 300 mg of zanidatamab-hrii as the active ingredient, accompanied by carefully formulated inactive ingredients: polysorbate 20 (0.63 mg), sodium succinate (4.3 mg), succinic acid (4.3 mg), and sucrose (567 mg).

Post-Reconstitution Characteristics

When reconstituted with 5.7 mL of sterile water for injection, it forms a solution with a concentration of 50 mg/mL, yielding an extractable volume of 6 mL.

The reconstituted product should appear as a colorless to pale yellow, clear to slightly opalescent solution with no visible particles.

The pH of the solution is precisely controlled at 4.6, a range that ensures drug stability while minimizing patient discomfort during administration.

Reconstitution requires professional operation: slowly direct the stream of water onto the inner wall of the vial and gently swirl until complete dissolution. Shaking or vigorous agitation is avoided.

Storage Methods for Ziihera (Zanidatamab-hrii)

Storage of Unreconstituted Product

Unreconstituted Ziihera must be stored refrigerated at a temperature range of 2°C to 8°C (36°F to 46°F).

Storage Specifications for Reconstituted Solution

The reconstituted solution contains no preservatives and must be used immediately or stored under specific conditions.

At room temperature (18°C to 24°C), the reconstituted solution can be stored for a maximum of 4 hours.

If refrigerated storage is required, maintain the same temperature range of 2°C to 8°C.

Storage Requirements for Diluted Infusion Solution

The storage conditions for the diluted infusion solution are more stringent.

It can be stored at room temperature for a maximum of 12 hours.

If these specified time limits are exceeded, the current infusion bag must be discarded, and a new one prepared.