Zimberelimab is a recombinant humanized? human IgG4 monoclonal antibody and an immune checkpoint inhibitor targeting programmed cell death protein 1 (PD-1). It is also known by the development codes GLS-010, AB-122 and WBP-3055. Zimberelimab is designed to bind to PD-1 and block interaction with its ligands, PD-L1 and PD-L2, thereby supporting activation of T-cell-mediated immune responses against tumor cells.
Zimberelimab has the CAS Registry Number 2259860-24-5 and FDA Unique Ingredient Identifier (UNII) ZBL7O904IL. Official Japanese pharmaceutical nomenclature information identifies zimberelimab as a recombinant anti-PD-1 monoclonal antibody derived from human IgG4 and produced in CHO cells. It has an approximate molecular weight of 147,000 Da.
Unlike conventional small-molecule APIs, Zimberelimab is a complex recombinant glycoprotein. It consists of two gamma-4 heavy chains and two lambda light chains. The official Japanese JAN database specifies that each heavy chain contains 450 amino acid residues, while each lambda light chain contains 216 amino acid residues. The antibody contains an S231P substitution in the heavy chain, characteristic of the engineered IgG4 molecule.
Zimberelimab is produced using Chinese hamster ovary (CHO) cells, a commonly used mammalian expression system for therapeutic monoclonal antibodies. Its biological structure and post-translational modifications require specialized analytical characterization that differs from the testing normally used for synthetic chemical APIs.
Zimberelimab is therefore best described as a recombinant monoclonal antibody API / biological active pharmaceutical ingredient rather than a conventional small-molecule pharmaceutical compound.
Zimberelimab is an anti-PD-1 immune checkpoint inhibitor. PD-1 is an inhibitory receptor expressed on activated T cells and other immune-cell populations. Binding of PD-1 to its ligands, PD-L1 or PD-L2, can reduce T-cell activity and contribute to immune evasion by tumor cells.
Zimberelimab binds to PD-1 and prevents interaction with PD-L1 and PD-L2. By interfering with this inhibitory signaling pathway, the antibody can enhance T-cell activity against tumor cells.
Experimental characterization of Zimberelimab has demonstrated binding to human PD-1 and blockade of PD-L1 and PD-L2 interactions. Research-grade material is commonly identified as GLS-010 or AB-122.
Zimberelimab has been investigated as an immuno-oncology therapeutic for multiple malignancies. Its development has included clinical research in cancers such as classical Hodgkin lymphoma, cervical cancer and non-small-cell lung cancer, among other oncology indications.
The compound has been evaluated as an intravenous infusion product. European clinical-trial documentation identifies Zimberelimab as AB-122, supplied as a concentrate for solution for injection or infusion and administered by the intravenous route. The same record identifies the active substance CAS number as 2259860-24-5.
Zimberelimab's pharmaceutical relevance is based on its activity as an immune checkpoint inhibitor and its ability to target the PD-1 pathway.
Zimberelimab has an approximate molecular weight of 147 kDa. The official JAN database describes the molecule as a glycoprotein consisting of two 450-amino-acid gamma-4 heavy chains and two 216-amino-acid lambda light chains.
The antibody is derived from human IgG4 and incorporates an S231P substitution in the heavy chain. This engineered IgG4 configuration is relevant to the structural and functional characteristics of the molecule.
Because monoclonal antibodies are glycosylated proteins rather than discrete low-molecular-weight organic molecules, their molecular weight may be reported as an approximate value rather than a single exact molecular mass.
Zimberelimab is produced using CHO cells. Mammalian expression systems such as CHO cells are widely used for recombinant therapeutic antibodies because they can support appropriate protein folding, disulfide-bond formation and glycosylation.
Manufacturing of Zimberelimab requires control of upstream cell culture, downstream purification, viral clearance, filtration, formulation and aseptic processing. The resulting drug substance must undergo extensive characterization to confirm identity, purity, potency and consistency.
Important manufacturing controls for a recombinant monoclonal antibody include host-cell protein, host-cell DNA, residual process impurities, aggregates, fragments, charge variants, glycosylation profile and microbial or endotoxin contamination.
Zimberelimab requires a combination of orthogonal analytical methods because no single analytical test can fully characterize a therapeutic monoclonal antibody.
Typical analytical approaches may include:
The exact acceptance criteria should be established through the manufacturer's validated analytical methods and applicable regulatory specifications.
Protein purity is an important quality attribute for Zimberelimab. Research-grade Zimberelimab products are commonly reported at greater than 99% purity, but research-material purity should not automatically be presented as the official commercial drug-substance release specification.
For a commercial pharmaceutical API, purity assessment should distinguish between monomeric antibody, aggregates, fragments and other product-related variants.
SEC-HPLC can be used to evaluate aggregate levels, while CE-SDS and other electrophoretic methods can assess molecular-size variants. Charge heterogeneity can be evaluated using chromatographic methods such as ion-exchange chromatography.
Clinical-trial documentation identifies Zimberelimab as a concentrate for solution for intravenous administration.
Research and development materials commonly report Zimberelimab at concentrations around 30 mg/mL, although the concentration should be tied to the specific formulation and product presentation rather than assumed to be an intrinsic API property.
For CMS purposes, it is preferable to distinguish between drug substance concentration and the concentration of a particular finished pharmaceutical formulation.
Zimberelimab is a recombinant protein supplied or formulated as an aqueous solution rather than as a conventional crystalline small-molecule powder.
Consequently, a conventional numerical "water solubility" value in mg/mL is not an appropriate universal API specification. Protein concentration, formulation composition, pH, ionic strength and excipients determine the physical state and stability of the antibody solution.
For this reason, Zimberelimab should be described as soluble in the aqueous formulation at the specified protein concentration, rather than assigning a generic small-molecule solubility number.
Quality control for Zimberelimab should focus on the critical quality attributes applicable to recombinant monoclonal antibodies.
These include:
Because Zimberelimab is a biological molecule, conventional parameters such as residue on ignition, melting point and specific rotation are not suitable primary release tests.
Zimberelimab is a specialized oncology biologic API relevant to pharmaceutical companies and biotechnology organizations involved in immune checkpoint inhibitor development.
A pharmaceutical-grade supply program should include appropriate documentation for identity, concentration, purity, potency, aggregates, charge variants and other relevant critical quality attributes.
Batch-specific documentation such as a Certificate of Analysis should accompany supplied material, with testing performed using validated methods appropriate for the recombinant antibody.
Zimberelimab should be clearly distinguished from other anti-PD-1 antibodies by its molecular identity, sequence characteristics, IgG4 framework and S231P heavy-chain substitution. Official JAN information confirms the recombinant antibody structure and CHO-cell production system.
Zimberelimab is a temperature-sensitive biological product and should be stored according to validated stability conditions established for the specific drug substance or formulation.
Research-grade Zimberelimab materials are commonly supplied under frozen conditions and may require storage at −80°C with avoidance of repeated freeze-thaw cycles. These conditions apply to specific research products and should not automatically be represented as the commercial pharmaceutical storage specification.
Commercial pharmaceutical storage conditions should always follow validated stability data and the applicable product specification.
Zimberelimab is a recombinant anti-PD-1 monoclonal antibody belonging to the human IgG4 class. It is also known as GLS-010, AB-122 and WBP-3055 and has CAS number 2259860-24-5.
The official Japanese JAN database identifies Zimberelimab as a recombinant anti-PD-1 antibody produced in CHO cells, consisting of two 450-amino-acid gamma-4 heavy chains and two 216-amino-acid lambda light chains, with an approximate molecular weight of 147,000 Da.
Its pharmaceutical relevance is associated with immune checkpoint inhibition through binding to PD-1 and blocking PD-L1/PD-L2 signaling. Zimberelimab has been investigated in several oncology settings and has been supplied in clinical development as an intravenous infusion product.
For pharmaceutical API manufacturing and supply, Zimberelimab requires biologic-specific quality control covering identity, protein concentration, purity, aggregates, fragments, potency, binding activity, charge variants, glycosylation and process-related impurities.
| Parameter | Specification |
|---|---|
| Appearance | white to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | NLT 99.0% |
| Loss on Drying | NMT 0.5% |
| Residue on Ignition | NMT 0.1% |
| pH (1% Solution) | 5.0 |
| Water Content | NMT 0.5% |