ICH5005 is an unconjugated, non-therapeutic recombinant analog of durvalumab, a fully human IgG1 monoclonal antibody directed against human PD-L1 (CD274; UniProt Q9NZQ7). It is supplied for research use only and is not the clinical drug, nor is it intended for human or veterinary use. Built around the PD-L1 target, this biosimilar reproduces the antigen-binding specificity of the originator, making it a convenient reference tool for studying PD-1/PD-L1 axis blockade in vitro and in preclinical models. Typical research applications include use as a benchmarking or reference standard in binding and neutralization assays, as an isotype-matched or positive control alongside other checkpoint reagents, and as a starting scaffold for ADC or engineering workflows. Material is offered at research grade with low endotoxin (<1 EU/mg; ultra-low <0.5 EU/mg options) and in bulk milligram-to-gram quantities to support assay development, screening, and in-vivo-grade preclinical formulation work. All content here is guidance for ichorbio to review and is not clinical documentation.
PD-L1 (programmed death-ligand 1, also called CD274 or B7-H1) is a type I transmembrane glycoprotein of the B7 immunoglobulin superfamily. It is expressed on antigen-presenting cells, many normal tissues under inflammatory conditions, and is frequently upregulated on tumor cells. PD-L1 engages its principal receptor PD-1 (PDCD1) on activated T cells, delivering an inhibitory signal that dampens T-cell proliferation, cytokine production, and cytotoxic activity, thereby maintaining peripheral tolerance and limiting immunopathology. PD-L1 also binds CD80 (B7-1). Tumors exploit this pathway to evade immune surveillance, so antibodies that block PD-L1 restore effector T-cell function. Durvalumab binds PD-L1 and prevents its interaction with PD-1 and CD80, releasing this checkpoint brake.