Invented by Rinpei Niwa, Mami TSUCHIYA, Kyowa Kirin Co Ltd
The Kyowa Kirin Co Ltd invention works as followsThe extra sugar chains that are bound at other amino acid residues than position 297 may have an influence on the constant region-mediated antibody activity, and could cause a uniformity problem in a therapeutic antibody preparation. A method is needed to control extra sugar chains that are bound to Asn residues in positions other than 297, according to the EU index, when N-glycoside linked sugar chains bind to Fc region antibodies. The present invention is an antibody composition comprising an Asn-X, Ser/Thr, (X represents another amino acids residue than Pro), sequence of amino acids at positions other than 297 to 299 in the EU index of an Fc region in a human IgG antibodies, where at least one amino substitution has been made from an Asn substitution to another amino acid, an X substitution to Pro, or an Ser/Thr substitution to other amino acids residue.
Background for Antibody Variants Composition
Field of Invention
This invention is a composition of antibody variants in which extra sugar chain residues bound to Asn at positions other that position 297 of the EU Index are reduced or deleted. The effector activity of antibody is also maintained.
Brief description of the background art
Non-patent Document 1: “Since antibody have high binding activity, binding specificity, and high stability in the blood, their application to the diagnosis, prevention, and therapeutic agents for various human diseases has been attempted.” Humanized antibodies and human chimeric antibody were also prepared using recombinant technologies from non-human animal antigens (Non-patent documents 2 to 5).
A humanized antibody is an antibody in which the complementarity determining regions (hereinafter referred to as CDR) of a human animal antibody are substituted with CDRs of a nonhuman antibody. Humanized antibodies are antibodies in which the complementarity-determining regions (hereafter called CDRs) of an animal human antibody have been replaced with CDRs from a nonhuman antibody.
Humanized antibodies and human chimeric antigens solved problems with non-human animal antibody preparations such as mouse antibodies. They also made it possible to apply monoclonal proteins to pharmaceutical preparations (Non Patent Documents 6-9). Humanized antibodies are already available in the United States as an anti-cancer treatment. (Non Patent Document 10).
These human chimeric and humanized antigens do show some effects at the clinical level. However, therapeutic antibodies with higher effects are needed.
In the phase III clinical trial, the response rate of Rituxan, a human chimeric anti-CD20 antibody (registered trademark) (Non Patent Document 11), which is manufactured by MEC/Roche/Genentech, was not more than 48 percent (complete remission 6 percent, partial remission 42%), and the average duration of the response was 12 months (Non Patent Document 12).
In the case of the combination of Rituxan and chemotherapy (CHOP, Cyclophosphamide Doxorubicin Vincristine) it was reported by the phase II trial that its response rate for recurrent non-Hodgkin’s lymphoma and low malignancy patients is 95% (55% complete remission, 45% partial remission), but there were side effects caused by CHOP (Non Patent Document 13).
In the case of Herceptin, a humanized anti-HER2 antibody manufactured by Genentech (registered trademark), it was reported in the phase III trial that the response rate for patients with metastatic breast cancer is only 15% and the average duration of the response is 9.1 month (Non Patent Document 14).
The molecular structure of the human antibody molecule, also known as immunoglobulin, is used to classify it into IgA isotypes, IgD isotypes, IgE isotypes, IgG isotypes, and IgM isotypes.
The antibody molecule is composed of two heavy chains, (hereinafter called H chain), and two light chains, (hereinafter called L chain).
An H-chain comprises individual domain structures that are called respectively an H chain variable area (hereinafter referred as VH), hinge, CH2 domains and CH3 domains at the N terminal. The CH2 and CH3 domains are also called the Fc region.
From the N-terminal, “An L Chain comprises individual domain structure which is called an L Chain variable region (hereinafter known as VL) or an L Chain constant region (hereinafter known as CL).
The H chain of IgG-type antibodies includes four subclasses, namely IgG1, IgG2, IgG3, and IgG4. In the constant region of the H chain, the IgG subclasses share a homology with almost 95% identity in amino acid sequence. The hinges are highly variable.
Although IgG subclasses are highly homologous in amino acid sequence (Non-patent document 15), they differ in their biological activity strength. The biological activities can include effector functions such as complement-dependent cytotoxicity, antibody-dependent cellular cytotoxicity and phagocytic function. These activities are important in eliminating pathogens and foreign substances in the body.
A family of Fc receptors (hereinafter referred to as Fc?R) is expressed on the surface of various leukocytes such as natural killer cells (hereinafter referred to as NK cell), monocytes, macrophages, granulocytes and the like. “A family of Fc?
Fc-R can be classified as active Fc-R, such as the FcRI, FcRIIa, and FcRIIIa, and inhibitory Fc-R, such as the FcRIIb. IgG antibodies bind strongly to these receptors, especially IgG1 or IgG3 for humans, so they can induce ADCC activity as well as phagocytosis.
ADCC activity” is a cell-lysis reaction that is caused by cytotoxic molecules, such as granzyme and perforin, released from NK cells. As a result, an antibody bound to a antigen binds mainly to Fc?RIIIa, on the surface of the NK cell via the Fc moiety. ADCC activity is generally arranged in the order IgG1>IgG3>>IgG4 IgG2 on Non-patent Documents 18, 19. The CH2 domain contains a binding site for Fc?RIIIa, which is located on the Fc. A crystal structure analysis reveals that the Fc?RIIIa molecules bind to the space between the two CH2 regions (Non-patent document 20).
CDC activity” is a reaction where an antibody bound to the antigen activates a cascade reaction of a group serum proteins called complement systems and lyses the targeted cell. CDC activity is high in human IgG1 and IgG3 and generally shows an order of IgG3?IgG1>>IgG2?IgG4. The complement system can be classified into C1-C9 components, with most being enzyme precursors that express enzyme activity through partial degradation.
The CDC activity is induced by a cascade of activation by the partial degradation of each component by the components from the previous step. Finally, a membrane attack complex, formed by C5-C9, is formed on the cell membrane. (Non Patent Documents 16-17). The CH2 domain is the site where C1q binds to the Fc region according to a study of the Fc region amino acids (Non-patent document 21).Click here to view the patent on Google Patents.