Cosibelimab is a fully human monoclonal antibody that targets programmed death-ligand 1 (PD-L1). It is an immuno-oncology active pharmaceutical ingredient belonging to the immune checkpoint inhibitor class. Cosibelimab binds to PD-L1 and blocks its interaction with PD-1 and B7.1 receptors, thereby supporting T-cell-mediated immune activity against tumor cells.
Cosibelimab is a recombinant monoclonal antibody produced using Chinese hamster ovary (CHO) cells. The molecule is an IgG antibody consisting of two heavy chains and two light chains. FDA documentation reports a molecular weight of approximately 147 kDa for the drug substance.
Cosibelimab is identified by CAS No. 2216751-26-5 and is also known by the development codes CK-301 and TG-1501.
Cosibelimab binds to PD-L1 and prevents its interaction with PD-1 and B7.1 receptors. Blocking these interactions reduces PD-1-mediated inhibitory signaling and enhances T-cell activity.
Cosibelimab-ipdl is an immune checkpoint inhibitor used in oncology. In the United States, the FDA approved UNLOXCYT (cosibelimab-ipdl) on December 13, 2024, for adults with metastatic cutaneous squamous cell carcinoma (mCSCC) or locally advanced cutaneous squamous cell carcinoma (laCSCC) who are not candidates for curative surgery or radiation.
Cosibelimab can be supplied as a biological pharmaceutical active ingredient for applicable research, development and manufacturing requirements, subject to appropriate quality, regulatory and supply conditions.
Quality evaluation of Cosibelimab should focus on biological and biopharmaceutical attributes including identity, purity, potency, protein concentration, aggregates, charge variants, glycosylation profile, host-cell proteins, residual host-cell DNA, endotoxin, bioburden and other applicable critical quality attributes.
Final acceptance criteria should always follow the approved product specification, validated analytical methods and batch-specific Certificate of Analysis (CoA).
| Parameter | Specification |
|---|---|
| Appearance | White to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Loss on Drying | NMT 1.0% |
| Residue on Ignition | NMT 0.2% |
| Heavy Metals | NMT 10 ppm |
| pH (1% Solution) | 2.0 – 4.0 |
| Individual Impurity | ≤ 0.5% |
| Water Content | NMT 0.5% |
| Melting Point | 150°C – 154°C |