JP-2022540524-A5 -

Dates

Publication Date

20230530

Application Date

20200710

Description

Claudin family proteins are major components of tight junctions widely distributed in epithelial cells. Similar in structure to other claudin family proteins, CLDN18.2 is a membrane protein with a molecular weight of approximately 27.8 kd, four transmembrane domains, and also possesses two relatively short extracellular domains, EC1 and EC2. What distinguishes CLDN18.2 from other claudin family proteins is its highly specific expression in highly differentiated epithelial cells of the stomach in normal tissues (Tureci O et al., Gene, 2011). In tumors derived from gastric epithelial cells, CLDN18.2 is expressed on the surface of a high percentage of tumor cells. High levels of CLDN18.2 expression have also been detected in lymph nodes of gastric cancer cells and in metastatic tumors of other tissues (Wol S. et al., Int. J. Cancer, 2013). CLDN18.2 is expressed in a high proportion of tumor cells, including those of gastric cancer, bile duct cancer, esophageal cancer, and pancreatic cancer. As a specific surface marker, CLDN18.2 is a potential target molecule for cancer treatment. The development of highly efficient antibody drugs against CLDN18.2 will enable the treatment of a wide range of cancers and has enormous application potential and market value. In a particular embodiment of the present invention, the antibody or its antigen-binding fragment has an Fc region. In a particular embodiment, when numbered using the EU numbering system, the antibody may have a glycosylation modification at Asn297. In a particular embodiment, the proportion of the glycosylation structure having fucose is 50% or less. In a particular embodiment, the proportion of the glycosylation structure having fucose is 30% or less, for example, 20% or less, 10% or less, 5% or less, 2% or less, or 1% or less. In a preferred mode of implementation, the proportion of the antibody having a fucose sugar chain structure is 0% to 1%. In other aspects, the present invention relates to compositions comprising an antibody or antigen-binding fragment thereof, or a conjugate, and one or more pharmaceutically acceptable carriers , excipients, and/or diluents. In certain embodiments, the composition further comprises one or more other therapeutic agents. Accordingly, in certain embodiments of the antibody or antigen-binding fragment of the present invention, the antibody has a reduced level of fucoseization. For example, in certain embodiments of the antibody or antigen-binding fragment of the present invention, the proportion of the Asn297 glycan structure having a fucose glycan structure is 60% or less, e.g., 50% or less, e.g., 40% or less, 30% or less, 20% or less, 10% or less, 5% or less, 2% or less, or 1% or less. In a certain embodiment, the proportion having a fucose glycan structure is 0%-10%, e.g., 0%-5%, 0%-2%, or 0%-1%. In a certain embodiment, the proportion having a fucose glycan structure is 0.1% or less. In other specific embodiments, there is no detectable fucose in the Asn297 glycan structure. In other aspects, the present invention relates to compositions comprising the antibody of the present invention or its antigen-binding fragment or conjugate, and one or more pharmaceutically acceptable carriers , excipients and/or diluents. The phrase “pharmaceutically acceptable” means a compound, material, composition and/or dosage form that, within reasonable medical judgment, is suitable for contact with human or animal tissue and is free from excessive toxicity, irritation, allergic reactions, or other problems or complications, and is commensurate with a reasonable benefit/risk ratio. For example, as used herein, the phrase “pharmaceutically acceptable carrier , excipient and/or diluent” means a pharmaceutically acceptable material, composition or medium, such as a liquid or solid filler, diluent, excipient, solvent, medium, encapsulating material, manufacturing aid or solvent encapsulating material, which is relevant to maintaining the stability, solubility or activity of the antibody or its antigen-binding fragment of the present invention. In this embodiment, to avoid bias in the antibody library due to individual differences and to ensure as much diversity as possible in the library, total RNA from 120 mononuclear cells derived from the peripheral blood and spleen of healthy adult individuals, as well as neonatal umbilical cord blood, was obtained, collected, and extracted. The RNA was reverse transcribed to synthesize single-stranded cDNA, and the VH, Vκ, and Vλ genes were amplified using variable region primers for different subgroups of antibodies. After mixing the amplified products in a fixed ratio , the heavy and light chain genes were ligated by PCR to form single-stranded antibodies (scFv), which were then cloned into phage plasmids by double enzyme digestion. Competent cells of E. coli SS320 were transformed with phage plasmids carrying the scFv genes by electroporation. After SS320 proliferated to the logarithmic phase, hel