CAP TODAY Pathology/Laboratory Medicine/Laboratory Management
June 2022—Bio-Rad Laboratories introduced a range of antibodies specific to cemiplimab (Libtayo) that inhibit the binding of the drug to its target, human programmed death receptor-1. The ready-made antibodies are suitable for developing selective and sensitive assays for the bioanalysis and drug monitoring of cemiplimab.
Cemiplimab acts as a checkpoint inhibitor by binding to PD-1 on T cells and blocking the interaction with its ligands, PD-L1 and PD-L2, thereby activating T cells to attack cancer cells. Three human IgG1 antibodies with varying levels of affinity are available for use as surrogate positive controls or calibrators in antidrug antibody assays. These are complemented by a TrailBlazer antibody with a SpyTag2 incorporated into its heavy chain, which enables site-directed conjugation or fast conversion to a bivalent Fab or an Ig-like format within an hour, the company says. By using these antibodies, a highly sensitive pharmacokinetic bridging ELISA can be developed to measure free drug.