Formulation comprising Anti-claudin18.2 antibody

Abstract

Provided herein is a pharmaceutical formulation, in particular a stable liquid formulation, which comprises a recombinant anti-Claudin18.2 antibody, a method for preparing the pharmaceutical formulation, and a therapeutic use of the pharmaceutical formulation.

Description

TECHNICAL FIELD The present invention relates to the field of antibody formulations. More specifically, the present invention relates to a pharmaceutical formulation, in particular to a stable liquid formulation, comprising a recombinant anti-Claudinl8.2 antibody, a method for preparing the pharmaceutical formulation, and a therapeutic use of the pharmaceutical formulation. BACKGROUND Claudinl8.2 belongs to the Claudin family of tight junction membrane proteins. The protein found in the cellular tight junctions exhibits abnormal overexpression in a range of malignancies, particularly malignancies of the digestive system. In contrast, the expression of the protein in healthy tissues is limited predominantly to differentiated gastric mucosal epithelial cells. Consequently, Claudinl8.2 has been proposed as a promising target for the development of antibody-based drugs for cancer treatment. Multiple pre-clinical and clinical trials of anti-Claudinl8.2 antibodies are ongoing for the treatment of digestive cancers, such as gastric cancer (GC), gastroesophageal junction (GEJ) cancer, esophageal cancer, and pancreatic cancer. For example, monoclonal antibody zolbetuximab has showed some promising results in clinical trial. In the field of medicine, liquid formulations of antibodies are the most desired form as they can be readily administered without any further preparation. Some liquid formulations of antibodies have been commercially available, such as AMJEVITA (adalimumab-atto) injection, for subcutaneous use. However, practical experience has shown that there are no general stabilization approaches for antibody proteins. Each drug requires a unique combination of excipients used at distinct concentrations to ensure product stability. This phenomenon is derived from the fact that each antibodies have a unique structural characteristic for antigen specificity. See, Ann L. Daugherty, et al., “Formulation and delivery issues for monoclonal antibody therapeutics”, Advanced Drug Delivery Reviews 58 (2006) 686- 706. There is a growing need for subcutaneous (SC) injection of antibody formulations, considering factors such as ease of administration and patient compliance. Due to delivery volume limitation, antibody solutions for SC administration need to be formulated at high concentrations to deliver effective doses. These high concentration present additional technical challenges, such as physical and chemical instability of antibodies and viscosity, which can hinder successful development and commercialization of such antibody formulations. So far, no high-concentration formulations of anti-claudinl8.2 antibodies have been reported. Therefore, there is still a need in the art for liquid formulations of anti-Claudinl8.2 antibodies that exhibit good stability, particularly at high antibody concentrations, to facilitate the therapeutic application of these antibodies. SUMMARY OF INVENTION The present invention addresses the aforementioned requirements by offering formulation technical solutions, as outlined in the claims. These formulations demonstrate exceptional protective effects on anti-Claudinl8.2 antibodies. Even at high concentrations, the antibodies in the formulations maintain physical and chemical stability while exhibiting low viscosity. This enables the subcutaneous administration of high-concentration anti-Claudinl 8.2 antibodies, effectively meeting the demands for the production and clinical application of Claudin 18.2 antibody products with elevated concentrations. In the first aspect, therefore the present disclosure provides a liquid antibody formulation, comprising: (i) an anti-Claudinl8.2 antibody protein; (ii) a buffer, (iii) a stabilizer, and (iv) a surfactant, wherein the pH of the liquid antibody formulation is about 5.0 to about 6.0. In an embodiment, the anti-Claudinl8.2 antibody protein comprises a VH region and a VL region, wherein the VH region comprises the heavy chain CDRs (HCDR1, HCDR2, HCDR3) contained in the heavy variable region as shown in SEQ ID NO: 1; and wherein the VL region comprises the light chain CDRs (LCDR1, LCDR2, LCDR3) contained in the light variable region as shown in SEQ ID NO: 2, preferably wherein the CDRs are defined according to Kabat, Chothia, IMGT, or any combination thereof. More preferably, the HCDR1, the HCDR2, the HCDR3, the LCDR1, the LCDR2 and the LCDR3 comprises the sequences as shown in SEQ ID NOs: 5-10, respectively. In an embodiment, the concentration of the anti-Claudinl8.2 antibody protein in the liquid antibody formulation is about 20 mg / mL to about 160 mg / mL, about 50 mg / mL to about 150 mg / mL, about 100 mg / mL to about 150mg / mL, or about llOmg / mL to about 130mg / ml, e.g., about 100 mg / mL, about 110 mg / mL, about 120 mg / mL, or about 130 mg / mL. Preferably, the concentration of the anti-Claudinl8.2 antibody protein in the liquid antibody formulation is 120mg / ml ± lOmg / ml. In an embodiment, the pH of the liquid antibody formulation is about 5.1 to about 5.5, for example, about 5.1, about 5.2, about 5.3, about 5.4 or about 5.5. Preferably, the pH of the liquid antibody formulation is about 5.3. Still preferably, the pH of the liquid antibody formulation is 5.3 ± 0.1. In an embodiment, the liquid antibody formulation comprises a buffer, selected from the group consisting of an acetate buffer and a histidine buffer. In a preferable embodiment, the acetate buffer comprises acetic acid, sodium acetate or combination thereof, more preferably, the acetate buffer is a buffer system consisting of acetic acid and sodium acetate. In another preferable embodiment, the histidine buffer comprises histidine, histidine hydrochloride or combination thereof, more preferably, the histidine buffer is a buffer system consisting of histidine and histidine hydrochloride. In an embodiment, the liquid antibody formulation comprises a stabilizer, for example, selected from the group consisting of polyol, disaccharide, amino acid and any combination thereof. In a further embodiment, the stabilizer is selected from the group consisting of sucrose, trehalose, sorbitol, mannitol, proline and any combination thereof. Preferably, the liquid antibody formulation comprises sucrose. In an embodiment, the liquid antibody formulation comprises a surfactant, for example, a polysorbate or a poloxamer. In a further embodiment, the surfactant is selected from the group consisting of polysorbate-80, polysorbate-20, polysorbate-60, polysorbate-40, and poloxamer 188. Preferably, the liquid antibody formulation comprises polysorbate-80. In an embodiment, the buffer is an acetate buffer or a histidine buffer; the stabilizer is sucrose; and the surfactant is polysorbate-80. In an embodiment, the liquid antibody formulation comprises: -the buffer in an amount of about 5mM to about 50mM, optionally about 5mM to about 20mM of an acetate buffer; or about 5 to about 20mM of a histidine buffer; - the stabilizer in an amount of about 100 to about 500 mM, optionally about 150 to about 350 mM, e.g., about 150 mM, about 180 mM, about 200 mM, about 220 mM, about 250 mM, about 300 mM, or about 350 mM; and / or - the surfactant in an amount of about 0.1 mg / mL to about 1 mg / mL, optionally about 0.2 mg / mL to about 0.8 mg / mL, e.g., about 0.2 mg / mL, about 0.3 mg / mL, about 0.4 mg / mL, about 0.5 mg / mL, about 0.6 mg / mL, about 0.7 mg / mL or about 0.8 mg / mL. In an embodiment, the liquid antibody formulation further comprises a chelating agent, optionally wherein the chelating agent is selected from the group consisting of EDTA, DTPA, and combination thereof. In a further embodiment, the concentration of the chelating agent is lOqM to lOOpM, optionally 20qM to 70qM, e.g., about 20qM, about 30qM, about 40qM, about 50qM, about 60pM, or about 70qM. In an embodiment, the liquid antibody formulation is an injection, preferably for subcutaneous, intravenous or intramuscular injection. In another embodiment, the liquid antibody formulation is an infusion, e.g., for intravenous infusion. In the second aspect, the present disclosure provides a solid antibody formulation obtained by solidifying the liquid antibody formulation according to the present invention. In an embodiment, the solid formulation is a lyophilized powder for injection. In the third aspect, the present disclosure provides a delivery device, comprising the liquid antibody formulation according to the present invention or the solid antibody formulation according to the present invention. In an embodiment, the delivery device is a pre-filled syringe. In a further embodiment, the pre-filled syringe is for use in injection, optionally subcutaneous, intravenous or intramuscular injection. In the fourth aspect, the present disclosure provides the liquid antibody formulation according to the present invention or the solid antibody formulation according to the present invention for use in therapy, especially for use in treatment or prevention of a cancer. In an embodiment, the cancer is a digestive cancer, e.g., gastric cancer (GC), gastroesophageal junction (GEJ) cancer, esophageal cancer, or pancreatic cancer. In the fifth aspect, the present disclosure provides a method of treating or preventing a cancer in a subject in need thereof, comprising administering to the subject a therapeutically effective amount of the liquid or solid antibody formulation according to the present invention. In an embodiment, the cancer is a digestive cancer, e.g., gastric cancer (GC), gastroesophageal junction (GEJ) cancer, esophageal cancer, or pancreatic cancer. In the sixth aspect, the present disclosure provides a use of the liquid antibody formulation according to the present invention or the solid antibody formulation according to the present invention in preparing a medicament. In an embodiment, the medicament is for treating or preventing a cancer, such as a digestive cancer, e.g., gastric cancer (GC), gastroesophageal junction (GEJ) cancer, esophageal cancer, or pancreatic cancer. In the seventh aspect, the present disclosure provides a method for preparing the liquid antibody formulation according to the present invention, which include the steps of: (a) producing a drug substance (DS) from a mixture comprising the antibody by a downstream process (DSP), and (b) formulating the drug substance into the liquid formulation. In an embodiment, a chelating agent is added into the formulation at step (b), preferably at an amount of about lOqM to about lOOpM, more preferably at an amount of about 20qM to about 70qM. In another embodiment, a chelating agent is added into a processing solution of the DSP at step (a), preferably at an amount of about lOqM to about 150qM, more preferably at an amount of about 30qM to about lOOqM. DETAILED DESCRIPTION The following description of the disclosure is merely intended to illustrate various embodiments of the disclosure. As such, the specific modifications discussed are not to be construed as limitations on the scope of the disclosure. It will be apparent to one skilled in the art that various equivalents, changes, and modifications may be made without departing from the scope of the disclosure, and it is understood that such equivalent embodiments are to be included herein. All references cited herein, including publications, patents and patent applications are incorporated herein by reference in their entirety. DEFINITIONS Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those of ordinary skill in the art. For the purposes of the present invention, the following terms are defined below. As used herein, the term "a," "an," "the" and similar terms used in the context of the present invention (especially in the context of the claims) are to be construed to cover both the singular and plural unless otherwise indicated herein or clearly contradicted by the context. The term "about", used in combination with a numerical value of a variable, refers to the indicated value and to all values that are within 5 percent of the indicated value. Therefore, reference to "about" a value herein includes (and describes) embodiments that are directed to that value per se. For example, description referring to "about X" includes description of "X". Reference to a "numeric range" herein is meant to be inclusive of the numbers defining the range. The term "and / or", when used to connect two or more options, should be understood to refer to any one of the options or any two or more of the options. As used herein, the term "comprise" or "comprising" is intended to include the described elements, integers or steps, but not to exclude any other elements, integers or steps. As used herein, the term "comprise" or "comprising", unless indicated otherwise, also encompasses the situation where the entirety consists of the described elements, integers or steps. For example, when referring to an antibody variable region "comprising" a particular sequence, it is also intended to encompass an antibody variable region consisting of the particular sequence. As used herein, the term “antibody” includes any immunoglobulin, monoclonal antibody, polyclonal antibody, multivalent antibody, bivalent antibody, monovalent antibody, multispecific antibody, or bispecific antibody that binds to a specific antigen. A native intact antibody comprises two heavy (H) chains and two light (L) chains. Mammalian heavy chains are classified as alpha, delta, epsilon, gamma, and mu, each heavy chain consisting of a variable region (VH) and a first, second, and third constant region (CHI, CH2, CH3, respectively); mammalian light chains are classified as X or k, while each light chain consisting of a variable region (VL) and a constant region. The antibody has a “Y” shape, with the stem of the Y consisting of the second and third constant regions of two heavy chains bound together via disulfide bonding. Each arm of the Y includes the variable region and first constant region of a single heavy chain bound to the variable and constant regions of a single light chain. The variable regions of the light and heavy chains are responsible for antigen binding. The variable regions in both chains generally contain three highly variable loops called the complementarity determining regions (CDRs) (light chain CDRs including LCDR1, LCDR2, and LCDR3, heavy chain CDRs including HCDR1, HCDR2, HCDR3). CDR boundaries for the antibodies and antigen-binding domains disclosed herein may be defined or identified by the schemes of Kabat, IMGT, AbM, Chothia, or Al-Lazikani (Al-Lazikani, B., Chothia, C., Lesk, A.M., J. Mol. Biol., 273 (4), 927 (1997); Chothia, C. et al., J Mol Biol. Dec 5; 186 (3): 651-63 (1985); Chothia, C. and Lesk, A.M., J. Mol. Biol., 196, 901 (1987); N.R. Whitelegg et al, Protein Engineering, vl3 (12), 819-824 (2000); Chothia, C. et al., Nature. Dec 21-28; 342 (6252) : 877-83 (1989); Kabat E.A. et al., National Institutes of Health, Bethesda, Md. (1991); Marie-Paule Lefranc et al, Developmental and Comparative Immunology, 27: 55-77 (2003); Marie-Paule 4 Lefranc et al, Immunome Research, 1 (3) , (2005) ; Marie-Paule Lefranc, Molecular Biology of B cells (second edition) , chapter 26, 481-514, (2015) ) . The three CDRs are interposed between flanking stretches known as framework regions (FRs), which are more highly conserved than the CDRs and form a scaffold to support the hypervariable loops. The constant regions of the heavy and light chains are not involved in antigen-binding, but exhibit various effector functions. Antibodies are assigned to classes based on the amino acid sequence of the constant region of their heavy chain. The five major classes of antibodies are IgA, IgD, IgE, IgG, and IgM, which are characterized by the presence of alpha, delta, epsilon, gamma, and mu heavy chains, respectively. Several of the major antibody classes are divided into subclasses or isotypes such as IgGl (gammal heavy chain), IgG2 (gamma2 heavy chain) , IgG3 (gamma3 heavy chain) , IgG4 (gamma4 heavy chain) , IgAl (alphal heavy chain) , or IgA2 (alpha2 heavy chain) . In certain embodiments, the antibody provided herein encompasses any antigen-binding fragments thereof. Examples of antigen-binding fragment include, without limitation, a Fab, a Fab', a F (ab1) 2, a Fd, an Fv fragment, a disulfide stabilized Fv fragment (dsFv), a (dsFv) 2, a bispecific dsFv (dsFv-dsFv1), a disulfide stabilized diabody (ds diabody), a single-chain antibody molecule (scFv), an scFv dimer (bivalent diabody), and a multispecific antibody. An antigen-binding fragment is capable of binding to the same antigen to which the parent antibody binds. As used herein, the term “percent (%) sequence identity” with respect to amino acid sequence is defined as the percentage of amino acid residues in a candidate sequence that are identical to the amino acid residues in a reference sequence, after aligning the sequences and, if necessary, introducing gaps, to achieve the maximum correspondence. Alignment for purposes of determining percent amino acid sequence identity can be achieved, for example, using publicly available tools such as BLASTN, BLASTp (available on the website of U.S. National Center for Biotechnology Information (NCBI), see also, Altschul S.F. et al, J. Mol. Biol., 215: 403-410 (1990); Stephen F. et al, Nucleic Acids Res., 25: 3389-3402 (1997)), ClustalW2 (available on the website of European Bioinformatics Institute, see also, Higgins D.G. et al, Methods in Enzymology, 266: 383-402 (1996) ; Larkin M.A. et al, Bioinformatics (Oxford, England) , 23 (21) : 2947-8 (2007) ) , and ALIGN or Megalign (DNASTAR) software. Those skilled in the art may use the default parameters provided by the tool, or may customize the parameters as appropriate for the alignment, such as for example, by selecting a suitable algorithm. In certain embodiments, the non-identical residue positions may differ by conservative amino acid substitutions. A "conservative amino acid substitution" is one in which an amino acid residue is substituted by another amino acid residue having a side chain (R group) with similar chemical properties (e.g., charge or hydrophobicity). In general, a conservative amino acid substitution will not substantially change the functional properties of a protein. In cases where two or more amino acid sequences differ from each other by conservative substitutions, the percent or degree of similarity may be adjusted upwards to correct for the conservative nature of the substitution. Means for making this adjustment are well known to those of skill in the art. See, e.g., Pearson (1994) Methods Mol. Biol. 24: 307-331, which is herein incorporated by reference. As used herein, the term “Claudin 18.2” is used interchangeably with “CLDN18.2”, and refers to a Claudin-18 splice variant 2 derived from mammals. In some embodiments, Claudinl8.2 is human Claudin 18.2. Exemplary sequence of human Claudinl8.2 includes the protein under NCBI Ref SeqNo. NP 001002026.1, and the protein under UniProtKB Accession Number P56856-2. In some embodiments, the Claudinl 8.2 is expressed on the surface of a cancer cell. As used herein, the term “anti-CLDN18.2 antibody” or “anti-Claudinl8.2 antibody” refers to an antibody that is capable of specific binding to CLDN18.2 (e.g. human CLDN18.2) with a sufficient affinity, for example, to provide for diagnostic and / or therapeutic use. As used herein, the term "anti-Claudinl8.2 antibody formulation" refers to a preparation comprising an anti- Claudinl 8.2 antibody as an active ingredient and a pharmaceutically acceptable excipient. The antibody formulation can be prepared, for example, as an aqueous liquid formulation, e.g., in a ready-to-use pre-filled syringe, or as a lyophilized formulation to be reconstituted (i.e., redissolved) by dissolution and / or suspension in a physiologically acceptable solution immediately prior to use. The term "lyophilized formulation" refers to a composition obtained or obtainable by a freeze-drying process of a liquid formulation. Preferably, it is a solid composition having a water content less than 5%, preferably less than 00 / J / 0. The term "reconstituted formulation" refers to a liquid formulation obtained by dissolving and / or suspending a solid formulation (e.g., a lyophilized formulation) in a physiologically acceptable solution. In some embodiments, the liquid formulation according to the present invention encompasses a reconstituted formulation. The term "room temperature" as used herein refers to a temperature of 15-30 °C, preferably 20-27 °C, and more preferably 25 °C. The term “drug substance” or “DS”, used interchangeably in the present disclosure, refers to the active pharmacological ingredient used in a finished pharmaceutical product (also known as drug product or DP) to achieve the desired therapeutic effect. Drug substances intended for human use are typically produced by a seria of chemical and / or biotechnological processes to ensure their purity, quality and safety. Drug substances that are purified to a pharmaceutical grade can be prepared into a formulation that contains the active drug substance(s) along with other ingredients to optimize the overall product properties, such as bioavailability, shelf life, and stability. The term “downstream process”, as used with respect to antibody drug substance, is used interchangeably with “DSP”. It refers to an operation(s) required for recovering and purifying the antibody from natural or man-made sources to produce a drug substance suitable for formulation. Depending on the nature of the sources, downstream process (DSP) may include different operations. In some instances, where the source is recombinant cells expressing the antibody of interest or a mixture derived therefrom, the DSP may include at least one or more or even all of the following steps: (i) harvest and filtration to separate the antibody from bulk cell debris, (ii) purification by chromatography, including but not limited to, protein A affinity chromatography, ion exchanged chromatography, mix-mode chromatography, or any combination thereof, (iii) virus inactivation and / or virus filtration, and (iv) buffer exchange and up-concentration by ultrafiltration and diafiltration (UFDF). The term “processing solution”, as used with respect to downstream process (DSP) of a drug substance, refers to a solution or mixture that is used or produced during various process steps of the downstream process. The compositions of the processing solutions can vary depending on the specific techniques employed in the process steps. A processing solution used for a filtration or a chromatography may be a load solution, a wash solution, or an elution solution. A processing solution obtained from a filtration or a chromatography may be a filtrate, a retentate, or an eluate. In the present disclosure, a processing solution obtained through a process step typically contains the antibody product of interest, and therefore is also referred to as a product pool or a pool from the process step. For example, a virus filtration pool or a VF pool is a processing solution obtained from a virus filtration operation; an ultrafiltration and diafiltration pool or a UFDF pool is a processing solution obtained from a UFDF operation; and a Tangential Flow Filtration pool is a processing solution obtained from a TFF operation. In respect of a chelating agent incorporated into a DSP processing solution, the phrase "a stabilizing effective amount" refers to an amount of the agent added into the processing solution, which is sufficient to enhance the stability of the liquid formulation produced by the DSP, as compared to the stability achieved without the incorporation of the agent. In some embodiments, the stabilizing effective amount of the chelating agent prevents surfactant degradation in the liquid formulation. In some embodiments, the stabilizing effective amount of the 6 chelating agent enhances antibody stability in the liquid formulation. In some embodiments, the stabilizing effective amount of the chelating agent prevents surfactant degradation and enhances antibody stability in the liquid formulation. In some embodiments, the surfactant degradation is the degradation of polysorbate 80. I. Antibody Formulation The present disclosure provides a stable liquid antibody formulation comprising (i) an anti-Claudinl8.2 antibody protein, (ii) a buffer, (iii) a stabilizer, and (iv) a surfactant, wherein the antibody formulation is at about pH 5.0-6.0. Anti-Claudinl8,2 antibody protein The anti-Claudinl8.2 antibody protein used in the formulation according to the present invention is an antibody that is capable of binding to a human Claudinl8.2 molecule with sufficient affinity such that the antibody can be used as a therapeutic agent and / or prophylactic agent targeting the Claudinl8.2 molecule. In some embodiments, the anti-Claudinl8.2 antibody protein comprises a VH region and a VL region, wherein the VH region comprises the heavy chain CDRs (HCDR1, HCDR2, HCDR3) contained in the heavy variable region as shown in SEQ ID NO: 1; and wherein the VL region comprises the light chain CDRs (LCDR1, LCDR2, LCDR3) contained in the light variable region as shown in SEQ ID NO: 2. Preferably, the CDRs are defined according to Kabat, Chothia, IMGT, or any combination thereof. More preferably, the HCDR1, the HCDR2, the HCDR3, the LCDR1, the LCDR2 and the LCDR3 comprises the sequences as shown in SEQ ID NOs: 5-10, respectively. In some embodiments, the anti-Claudinl8.2 antibody protein comprises a VH region comprising SEQ ID NO: 1 or a sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or higher identity thereto, and a VL region comprising SEQ ID NO: 2 or a sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or higher identity thereto. In some preferable embodiments, the anti-Claudinl8.2 antibody protein comprises a VH region comprising SEQ ID NO: 1 and a VL region comprising SEQ ID NO: 2. In some embodiments, the anti-Claudinl8.2 antibody protein comprises a heavy chain comprising SEQ ID NO: 3 or a sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or higher identity thereto, and a light chain comprising SEQ ID NO: 4 or a sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or higher identity thereto. In some preferable embodiments, the anti-Claudinl8.2 antibody protein comprises a heavy chain comprising SEQ ID NO: 3 and a light chain comprising SEQ ID NO: 4. In some embodiments, the anti-Claudinl8.2 antibody protein is an intact antibody comprising two heavy (H) chains and two light (L) chains. In some embodiments, the anti-Claudinl8.2 antibody protein is a IgG antibody, e.g., IgGl, IgG2, IgG3, or IgG4 antibody. In some embodiments, the anti-Claudinl8.2 antibody protein comprise a constant region derived from human. In some embodiments, the anti-Claudinl8.2 antibody protein is a IgGl antibody, more especially a IgGl antibody comprising a constant region derived from human. In some embodiments, the anti-Claudinl8.2 antibody protein comprises a constant region of a heavy chain as shown in SEQ ID NO: 11, or at least 90%, 95%, 96%, 97%, 98% or 99% identity thereto. In some embodiments, the anti-Claudinl8.2 antibody protein comprises a constant region of a kappa light chain. In some embodiments, the constant region of a kappa light chain is derived from human. In some embodiments, the anti-Claudinl8.2 antibody protein comprises a constant region of a kappa light chain as shown in SEQ ID NO: 12, or at least 90%, 95%, 96%, 97%, 98% or 99% identity thereto. In some preferable embodiments, the anti-Claudinl8.2 antibody protein is the anti-Claudinl8.2 monoclonal antibody disclosed in WO2021 / 032157, the disclosures of which are hereby expressly incorporated by reference, consisting of two heavy chains having the sequence as shown in SEQ ID NO: 3 and two light chains having the sequence as shown in SEQ ID NO: 4. In some embodiments, the anti-Claudinl8.2 antibody protein is recombinantly expressed in mammal cells, such as 7 HEK293 cells or in CHO cells. The concentration of the anti-Claudin 18.2 antibody protein in the liquid formulation according to the present invention may vary with factors such as the nature and characteristics of the formulation, and administration amount and administration mode of the formulation. In some embodiment, the concentration of the anti-Claudinl8.2 antibody protein in the liquid antibody formulation is about 20 mg / mL to about 160 mg / mL, about 50 mg / mL to about 150 mg / mL, about 100 mg / mL to about 150mg / mL, or about llOmg / mL to about 130mg / ml, e.g., about 100 mg / mL, about 110 mg / mL, about 120 mg / mL, or about 130 mg / mL. Preferably, the concentration of the anti-Claudinl8.2 antibody protein is more than lOOmg / ml. Still preferably, the concentration of the anti-Claudinl8.2 antibody protein is less than 150mg / ml. More preferably, the concentration of the anti-Claudinl 8.2 antibody protein is 120mg / ml ± lOmg / ml. Most preferably, the concentration of the anti-Claudinl 8.2 antibody protein is 120mg / ml. Buffer Buffers are substances that help maintain the pH of a solution within an acceptable range. In some embodiments, the formulation according to the present invention comprises a buffer, which is selected to maintain the pH of the formulation at about 5.0 to 6.0, e.g., about 5.0 to 5.5. In some embodiments, the antibody formulation comprising the buffer has a pH of about 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7 or 5.8. In some preferable embodiments, the antibody formulation has a pH of 5.3 ± 0.2, preferably a pH of 5.3. In some embodiments, the formulation according to the present invention comprises a buffer in an amount of about 5mM to about 50mM, for example, about 5mM, about lOmM, about 15mM, about 20mM, about 25mM, about 30mM, about 35mM, about 40mM, about 45mM or about 50mM. In an embodiment, the liquid antibody formulation comprises an acetate buffer or a histidine buffer. In one preferable embodiment, the acetate buffer comprises acetic acid, sodium acetate or combination thereof, more preferably, the acetate buffer is a buffer system consisting of acetic acid and sodium acetate. In another preferable embodiment, the histidine buffer comprises histidine, histidine hydrochloride or combination thereof, more preferably, the histidine buffer is a buffer system consisting of histidine and histidine hydrochloride. In some embodiments, the formulation of the present invention comprises a histidine buffer, especially a buffer system consisting of histidine and histidine hydrochloride, in an amount of about 5 to about 50 mM, particularly about 5 to about 20 mM, e.g., about 5mM, about 10 mM, about 15 mM, or about 20 mM. In a preferable embodiment, the formulation of the present invention comprises about 10 mM of a histidine buffer, which preferably consists of histidine and histidine hydrochloride. In some embodiments, the formulation of the present invention comprises an acetate buffer, especially a buffer system consisting of acetic acid and sodium acetate, in an amount of about 5 to about 50 mM, particularly about 5mM to about 20 mM, e.g., about 5 mM, about 10 mM, about 15mM, or about 20 mM. In a preferable embodiment, the formulation of the present invention comprises about 10 mM of an acetate buffer, which preferably consists of acetic acid and sodium acetate. In another preferable embodiment, the formulation disclosed herein comprises about 0.12 mg / mL of glacial acetic acid and about 1.08 mg / mL of sodium acetate trihydrate. Stabilizer Stabilizers suitable for use in the liquid formulation according to the present invention can be selected from saccharides, polyols, amino acids, and any combinations thereof. Saccharides that may be used as a stabilizer include, but are not limited to, sucrose, trehalose, maltose, and any combination thereof. Polyols that may be used as a stabilizer include, but are not limited to, sorbitol, mannitol, and any combination thereof. Amino acids that may be used as a stabilizer include, but are not limited to, arginine, methionine, glycine, proline, and any combination 8 thereof. In some embodiments, the liquid formulation according to the present invention comprises a stabilizer, for example, selected from the group consisting of polyol, disaccharide, amino acid and any combination thereof. In a further embodiment, the stabilizer is selected from the group consisting of sucrose, trehalose, sorbitol, mannitol, proline and any combination thereof. Preferably, the liquid antibody formulation comprises sucrose. In some embodiments, the liquid formulation according to the present invention comprises a stabilizer in an amount of about 100 to about 500 mM, optionally about 150 to about 350 mM, e.g., about 150 mM, about 180 mM, about 200 mM, about 220 mM, about 250 mM, about 300 mM, or about 350 mM. In some embodiments, the stabilizer is sucrose. In one embodiment, the liquid formulation according to the present invention comprises sucrose as a stabilizer. The amount of sucrose in the liquid formulation may be about 50 to about 100 mg / mL, preferably about 60mg / ml to about 80 mg / mL, e.g., about 60mg / ml, about 65mg / ml, about 70mg / ml, about 75mg / ml, about 80mg / ml. In a preferable embodiment, the amount of sucrose in the liquid formulation is about 70 mg / ml. In some embodiments, sucrose may be the sole stabilizer in the liquid formulation according to the present invention. Surfactant A surfactant is a type of compound that may be added to a liquid formulation to reduce the surface tension. Surfactants consist of molecules with both hydrophilic (water-attracting) and hydrophobic (water-repelling) regions, which allows them to interact with both water and non-water substances. In a liquid formulation, in some instances, a surfactant can be used to improve the overall stability and performance of the product. In some embodiments, surfactants that can be used in the liquid formulation according to the present invention include, but are not limited to, polysorbate-based surfactants (e.g., polysorbate 80, polysorbate 20), poloxamer and polyethylene glycol. In some embodiments, the liquid antibody formulation according to the present invention comprises a surfactant, for example, a polysorbate or a poloxamer. In a further embodiment, the surfactant is selected from the group consisting of polysorbate-80, polysorbate-20, polysorbate-60, polysorbate-40, and poloxamer 188. Preferably, the liquid antibody formulation comprises polysorbate-80. The amount of the surfactant in the liquid formulation according to the present invention may vary based on factors such as the specific properties desired for the formulation and its intended purpose. The amount of the surfactant maybe about 0.1 mg / mLto about 1 mg / mL, optionally about 0.2 mg / mLto about 0.8 mg / mL, e.g., about 0.2mg / mL, about 0.3 mg / mL, about 0.4 mg / mL, about 0.5 mg / mL, about 0.6 mg / mL, about 0.7 mg / mL or about 0.8 mg / mL. In some embodiments, the liquid formulation according to the present invention comprises the surfactant polysorbate 80 in an amount of about 0.1 mg / ml to about Img / mL, e.g., about 0.2 mg / mL, about 0.3 mg / mL, about 0.4 mg / mL, about 0.5 mg / mL, about 0.6 mg / mL, about 0.7 mg / mL, about 0.8 mg / mL, about 0.9mg / ml or about Img / ml. Preferably, the amount of polysorbate 80 is about 0.3mg / ml to about 0.6mg / ml, more preferably about 0.5 mg / ml. In some embodiments, polysorbate 80 may be the sole surfactant in the liquid formulation according to the present invention. Other excipients The liquid antibody formulation according to the present invention may or may not comprise other excipients. Such other excipients include, for example, antimicrobials, antistatic agents, antioxidants, chelating agents, gelatin, and the like. These and other known pharmaceutical excipients and / or additives suitable for use in the formulation 9 disclosed herein are well known in the art, for example, as listed in "The Handbook of Pharmaceutical Excipients, 4th edition, edited by Rowe et al., American Pharmaceuticals Association (2003); and Remington: the Science and Practice of Pharmacy, 21st edition, edited by Gennaro, Lippincott Williams & Wilkins (2005)". In some embodiments, the liquid formulation further comprises a chelating agent, optionally wherein the chelating agent is selected from the group consisting of EDTA, DTPA, their salts, and combination thereof. In some embodiments, the concentration of the chelating agent is lOpM to lOOpM, optionally 20pM to 70pM, e.g., about 20pM, about 30pM, about 40pM, about 50pM, about 60pM, or about 70pM. In some embodiments, the chelating agent is EDTA or its salt, especially sodium salt. In some preferably embodiments, the amount of EDTA in the liquid formulation is about 40pM to 60pM, preferably about 50pM. Illustrative formulation embodiments In some preferable embodiments, the liquid antibody formulation according to the present invention comprises: (i) about 100 mg / mL to aboutl50 mg / mL of the anti-Claudinl8.2 antibody protein; (ii) about 5 mM to about 20 mM of an acetate buffer or about 5 mM to 20 mM of a histidine buffer; (iii) about 50 mg / mL to about 100 mg / mL of sucrose; (iv) about 0.2 mg / mL to about 0.8 mg / mL of polysorbate 80; and optionally, (v) about 20pM to about 70pM of EDTA; wherein the pH of the liquid formulation is about 5.1 to about 5.5, preferably about 5.3. In some further preferable embodiments, the liquid antibody formulation according to the comprises: (i) about 110 to about 130 mg / mL of the anti-Claudinl8.2 antibody protein, (ii) about 10 mM of an acetate buffer or about 10 mM of a histidine buffer, (iii) about 60 mg / mL to about 80 mg / mL of sucrose, (iv) about 0.3 mg / mL to about 0.6 mg / mL of polysorbate 80, and optionally (v) about 40 pM to about 60 pM of EDTA; wherein the pH of the liquid formulation is about 5.1 to about 5.5, preferably about 5.3. In some further preferable embodiments, the liquid antibody formulation according to the comprises: (i) about 120 mg / mL anti-Claudinl8.2 antibody protein; (ii) about lOmM of an acetate buffer consisting of acetic acid and sodium acetate; (iii) about 70 mg / mL of sucrose; and (iv) about 0.5 mg / mL of polysorbate 80, wherein the pH of the liquid formulation is about 5.1 to about 5.5, preferably about 5.3. In some further preferable embodiments, the liquid antibody formulation according to the comprises: (i) about 120 mg / mL anti- Claudinl8.2 antibody protein; (ii) about lOmM of an acetate buffer consisting of acetic acid and sodium acetate; (iii) about 70 mg / mL of sucrose; (iv) about 0.5 mg / mL of polysorbate 80; and (v) about 50pM of EDTA; wherein the pH of the liquid formulation is about 5.1 to about 5.5, preferably about 5.3. In some further preferable embodiments, the liquid antibody formulation according to the comprises: present invention present invention present invention present invention (i) about 120 mg / mL anti- Claudinl8.2 antibody protein; (ii) about lOmM of a histidine buffer consisting of histidine and histidine hydrochloride; (iii) about 70 mg / mL of sucrose; and (iv) about 0.5 mg / mL of polysorbate 80; wherein the pH of the liquid formulation is about 5.1 to about 5.5, preferably about 5.3. In some further preferable embodiments, the liquid antibody formulation comprises: (i) about 120 mg / mL anti-Claudinl8.2 antibody protein; (ii) about lOmM of a histidine buffer consisting of histidine and histidine hydrochloride; (iii) about 70 mg / mL of sucrose; (iv) about 0.5 mg / mL of polysorbate 80; and (v) about 50pM of EDTA, wherein the pH of the liquid formulation is about 5.1 to about 5.5, preferably about 5.3. In some embodiments, the viscosity of the liquid antibody formulation is less than about lOmPa-s, about 9 mPa-s, 8 mPa-s, about 7 mPa-s, about 6 mPa-s, about 5 mPa-s, or about 4 mPa-s. In some preferable embodiments, the viscosity is about 5 mPa-s. Preferably, the viscosity is measured by a viscometer, especially measured as described in the Examples. Stability of Formulation The liquid formulation according to the present invention is stable. In some embodiments, the liquid formulation according to the present invention is chemically stable. In some embodiments, the liquid formulation according to the present invention is physically stable. In some embodiments, the liquid formulation according to the present invention is biologically stable. A variety of analytical techniques are known in the art for determining the stability of antibody proteins in a formulation. See, e.g., Peptide and Protein Drug Delivery, 247-301, Vincent Lee Ed., Marcel Dekker, Inc., New York, N.Y., Pubs (1991) and Jones, A. Adv. Drug Delivery Rev. 10: 29-90 (1993). Generally, stability of an antibody formulation is determined at a selected temperature and for a selected time under a selected condition. For example, a long-term storage assay may be used, in which the storage time and condition for the assay may be selected based on the expected storage condition and shelf life of the formulation of interest. Alternatively, an accelerated stability assay or a forced stability assay may be used to assess the stability and robustness of an antibody formulation. In an accelerated assay, the formulation is placed under temperature conditions that an antibody formulation may encounter during manufacture, storage or transportation, for example, at 25°C±2°C and 60±5% RH. In a forced assay, the formulation is placed under extreme temperature conditions that accelerate degradation, aggregation, or chemical modification of antibodies, for example, at 40°C±2°C and 75±5% RH. In addition, agitation assay may be used to assess the tolerance of antibodies to shear forces, for example, under the conditions of 200rpm at 25 °C in dark, as described in the Examples. These assays under stressed conditions help in predicting the long-term stability of an antibody formulation under various environmental factors. As used herein, "stable" antibody formulation refers to a formulation where the antibody retains an acceptable degree of physical and / or chemical stability after storage, shaking and / or repeated freezing-thawing under a specified condition. In some embodiments, an antibody formulation is considered "stable" if about 90%, about 95%, about 96%, about 97%, about 98%, or about 99% of the antibodies in the formulation maintain their structure or desired biological function after the storage, shaking and / or repeated freezing-thawing. In some embodiments, an antibody formulation is considered "stable" if less than about 10%, about 5%, about 4%, about 3%, about 2%, about 1% of the antibodies in the formulation are found to be aggregated, degraded, or chemically modified after the storage, shaking and / or repeated freezing-thawing. In some embodiments, an antibody formulation is considered stable if it can withstand the processes and conditions involved in manufacturing, transportation, and long-term storage, with minimal or no reduction in the biological activity of the antibody. In the context of antibody formulation, "physical stability" refers to the ability of the formulation to maintain the physical attributes of the antibody over time. This includes, but not limited to, the ability to maintain the structural integrity of the antibody molecules, prevent aggregation, degradation or precipitation, and avoid denaturation or unfolding. A formulation can be considered to maintain its physical stability if the antibodies in the formulation do not exhibit aggregation, degradation, fragmentation, unfolding, precipitation, turbidity and / or denaturation, or exhibits minimum aggregation, degradation, fragmentation, unfolding, precipitation, turbidity and / or denaturation after a period of stressed treatment, e.g., in stability assays or agitation assays described herein. There are various methods available in the art to detect the physical stability of a formulation, including but not limited to, visual inspection, micro-flow imaging (MFI), dynamic light scattering (DLS), size exclusion chromatography (SEC-HPLC), and non-reduced capillary electrophoresis-sodium dodecyl sulfate (nrCE-SDS). Visual inspection may be conducted by a clarity detector to provide the information about the appearance, color and / or visible particles of the formulation. Flow microscopy can be used to determine sub-visible particles in the formulation. Dynamic light scattering (DLS) is an effective technique for determination of the size distribution and the colloidal stability of antibody protein molecules in the formulation solution. SEC-HPLC is a technique common for determining mAb purity. The technique separates mAbs into three major species: high molecular weight species (HMW), main peak (predominantly antibody monomer), and low molecular weight species, and therefore can be used to detect size variants of the antibody within a formulation. Non-reduced CE-SDS is another technique particularly useful for detection of changes in the integrity, aggregation, or fragmentation of the antibodies. By analyzing the integrity of the antibodies, non-reduced CE-SDS can reveal the presence of intact antibody species and degraded antibody species. As appreciated by persons skilled in the art, the main peaks detected by SEC-HPLC and nrCE-SDS reflect the antibody purity in the formulation, which can be calculated by dividing the area of the main peak by the total area of all peaks together. In some embodiments, an antibody formulation is considered as maintaining physical stability if the purify of the antibody in the formulation, as measured by SEC-HPLC, is greater than about 90%, preferably greater than 95%, 96%, 97%, 98% or 99% after a period of stressed treatment, e.g., in stability assays or agitation assays described herein. In some embodiments, an antibody formulation is considered as maintaining physical stability if the purify of the antibody in the formulation, as measured by nrCE-SDS, is greater than about 80% or about 85%, preferably greater than 90%, 92%, 94%, 96% or 98% after a period of stressed treatment, e.g., in stability assays or agitation assays described herein. In the context of antibody formulation, "chemical stability" refers to the ability of the formulation to maintain the chemical attributes of the antibody over time. Factors that can impact the chemical stability of antibody formulations include pH, temperature, light exposure, presence of reactive impurities, and interactions with excipients. A formulation can be considered to maintain its chemical stability if the antibodies in the formulation do not exhibit significant chemical changes after aperiod of stressed treatment, e.g., in stability assays or agitation assays described herein. Most of the chemical instability results from the formation of covalently modified forms of the antibody. Chemical modifications of mAbs can result in charge heterogeneity by changing their isoelectric pH (pl) values. An increase of overall negative charges (decreasing pl values), as seen with deamidation, results in acidic variants, while an increase of overall positive charges (increasing pl value), as seen in oxidation or succinimide formation, results in basic variants. Cation exchange chromatography (CEX) can be used to detect charge heterogeneity of the antibody in a formulation. See, e.g., Chromatographic analysis of the acidic and basic species of recombinant monoclonal antibodies, MAbs. 2012 Sep 1; 4(5): 578-585, doi: 10.4161 / mabs.21328. When analyzed by cation exchange chromatography, these charge variants of the antibody are generally referred to as acidic or basic species as compared with the main species of the antibody that elute in the main peak. Acidic species elute earlier than the main peak from CEX, while basic species elute later than the main peak from CEX. Therefore, as appreciated by persons skilled in the art, the main peak, acidic peak, and basic peak detected by cation exchange chromatography reflect the proportions of the antibody main species and the acidic and basic charge variants present in the formulation, respectively. In some embodiments, the chemical stability of an antibody formulation is assessed after a period of stressed treatment, e.g., in stability assays or agitation assays described herein., using cation exchange chromatography and as compared to the formulation that has not undergone stressed treatment. In some embodiments, the antibody formulation is considered as maintaining chemical stability if the change in the main species and / or the charge variants of the antibody protein after the stressed treatment is less than 50%, 40%, 30%, 20%, 10% or 5%, as compared to the unstressed formulation. In some embodiments, the decrease is relative to an initial value at TO (i.e., the time before the start of the stress treatment). In the context of antibody formulation, "biological stability" refers to the ability of the formulation to maintain the biological activity and function of the antibody over time. A biological stability assay can be performed to corroborate the conservation of antibody activity, such as binding affinity and specificity to target antigen, and desired function, such as effector functions, e.g., ADCC, CDC or both. In some embodiments, the biological stability of an antibody formulation is assessed after a period of stressed treatment, e.g., in stability assays or agitation assays described herein, using a cell-based potency assay and as compared to the formulation that has not undergone stressed treatment. In some embodiments, the antibody formulation is considered as maintaining biological stability if the decrease in the activity of the antibody protein is less than 50%, 40%, 30%, 20%, 10% or 5%, as measured by a cell-based potency assay and as compared to the unstressed formulation. In some embodiments, the decrease is relative to an initial value at TO (i.e., the time before the start of the stress treatment). In some embodiments, the cell-based potency assay detects the ADCC activity induced by the antibody. In some embodiments, the cell-based potency assay is an assay based on a bioluminescent reporter gene and the mechanism of action of ADCC, e.g., an assay as described in the Examples. Polysorbates (PSs) are a class of surfactants commonly used in the formulation of protein therapeutic agents to provide protection against denaturation and aggregation. When the PS in these drug formulations degrades, loss of stabilization of the protein therapeutic formulation may occur, resulting in particulate formation or other undesirable changes in product critical quality attributes. See, e.g., Ravuri S K Kishore et al., The degradation of polysorbates 20 and 80 and its potential impact on the stability of biotherapeutics, Pharm Res, 2011 May; 28(5): 1194-210, doi: 10.1007 / sll095-011-0385-x; and Sisi Zhang, Prediction of long-term polysorbate degradation according to shortterm degradation kinetics, MAbs. 2023; 15(1): 2232486, doi: 10.1080 / 19420862.2023.2232486. For an antibody formulation comprising a polysorbate surfactant, in some instances, PS degradation in the formulation is detected, preferably in combination with physical / chemical / biological stability assays, to reflect the stability of the formulation. A variety of methods have been developed to track PS changes in an antibody formulation, including but not limited to, direct measurement of PS with a liquid chromatography-charged aerosol detector (LC-CAD) or an evaporative light scattering detector, or tracking changes in degradation byproducts of PS, such as FFAs from hydrolysis. In some embodiments, the impact of PS on the stability of an antibody formulation is examined in an accelerated stability assay, a forced stability and / or an agitation assay, by detection of the change of PS content. In some embodiments, the PS is Polysorbate-80. In some embodiments, the formulation is considered stable if the change in the amount of the surfactant (especially, polysorbate 80) is less than 0.01% or 0.02%, relative to an initial value at TO (i.e., the time before the start of the stress treatment). In some embodiments, the change in PS content is assayed after storage of the formulation at 2-8 °C for at least 24 months, at room temperature for at least 2 or 4 months, or at 40±2 °C for at least 1 month or 2 months. In some embodiments, the liquid formulation according to the present invention is stable after storage at 2-8 °C for 13 at least 24 months, at room temperature for at least 2 months, or at 40±2 °C for at least 1 month. In some embodiments, the liquid formulation according to the present invention is stable after shaking at room temperature in the dark at 200rpm for about 1 day to about 7 days. The stability, including physical stability, chemical stability, biological stability and Polysorbate degradation, of the liquid formulation according to the present invention may be assayed by various techniques known in the art and mentioned above, and preferably by the assays as described in the Examples. In some embodiments, the liquid antibody formulation according to the present invention, after storage, e.g., at 28 °C for at least 24 months, at room temperature for at least 2 months, or at 40±2 °C for at least 1 month, is stable and preferably has one or more of the following characteristics: (i) a purity of the antibody protein greater than 90%, 95%, 96%, 97%, 98% or 99%, as measured by SEC-HPLC, especially as described in the Examples; (ii) a purity of the antibody protein greater than 80%, 85%, 90%, 92%, 94%, 96% or 98%, as measured by nonreduced CE-SDS, especially as described in the Examples; (iii) the change in the main species and / or the charge-variants of the antibody protein less than 50%, 40%, 30%, 20%, 10% or 5%, relative to an initial value, as measured by cation exchange chromatography, especially as described in the Examples; (iv) the decrease in the activity of the antibody protein less than 50%, 40%, 30%, 20%, 10% or 5%, relative to an initial value, as measured by a cell-based potency assay, especially as described in the Examples, and optionally, (v) the change in the amount of the surfactant (especially, polysorbate 80) less than 0.01% or 0.02%, relative to an initial value. II. Preparation of Formulation The present disclosure provides a method for preparing the liquid formulation according to the present invention. The anti-Claudinl8.2 antibody used in the formulation can be prepared using techniques known in the art for the production of antibodies. For example, the antibody can be recombinantly prepared from recombinant cells, such as mammal cells, e.g., HEK293 cells or CHO cells. Following the completion of the antibody expression, downstream process (DSP) is typically used to isolate, purify and concentrate the expressed antibody from complex cell culture mixtures to provide a drug substance. Then, the drug substance can be formulated to achieve the required antibody protein concentration and introduce excipients at the desired levels. Techniques for isolating, purifying and concentrating therapeutic antibodies to pharmaceutical grade are well known in the art. The platform process for mAb purification is typically comprised of two or three column chromatography steps: a primary affinity capture column, and one or two subsequent polishing chromatography steps. Cation exchange (CEX) and anion exchange (AEX) chromatography are often used as the polishing chromatography columns to reduce impurities (e.g., aggregate, DNA, host cell protein [HCP], and virus) to acceptable levels prior to formulation. As the AEX step is operated in flow-through mode and dedicated for the removal of DNA and virus, the CEX step is usually operated in bind-and-elute mode to resolve monomer from aggregate in addition to other impurities. See, e.g., Cassia Andrade et al. (An Integrated Approach to Aggregate Control for Therapeutic Bispecific Antibodies Using an Improved Three Column Mab Platform-Like Purification Process, Biotechnol Prog. 2019 Jan-Feb; 35(1): e2720, doi: 10.1002 / btpr.2720), describing a conventional mAb three column platform purification process; Tugcu et al. (Maximizing productivity of chromatography steps for purification of monoclonal antibodies, Biotechnology and Bioengineering 99 (2008) 599-613), describing a monoclonal antibody purification method with three columns, in which ion exchange chromatography (anionic exchange chromatography [AEX] and / or cation 14 exchange chromatography [CEX]) is used after a protein A capture step; and Kelley et al. (Weak partitioning chromatography for anion exchange purification of monoclonal antibodies, Biotechnology and Bioengineering 101 (2008) 553-566), describing a two-column purification method in which a weak partitioning anion exchange resin is used after protein A affinity chromatography. In addition to protein A affinity chromatograph and ion exchange chromatograph, there are other techniques that are utilized for obtaining pure antibodies, including but not limited to size exclusion chromatograph, hydrophobic interaction chromatography, mix-mode chromatograph, protein G / protein L affinity chromatograph, precipitation (e.g., use of reagents such as polyethylene glycol or ammonium sulfate), filtration (e.g., virus filtration(VF), ultrafiltration (UF), diafiltration (DF), and tangential flow filtration (TFF)). Each protein purification method comes with its unique advantages and can be chosen and combined based on the specific requirements of the drug substance to be formulated. Generally, monoclonal antibodies recombinantly produced can be purified using conventional purification methods to provide a drug substance with sufficient reproducibility and proper purity for the formulation of antibody formulations. For example, after the antibody is secreted from the recombinant expression cells into the culture medium, the supernatant of the cell culture can be concentrated using a commercially available protein concentration filter, e.g., Amicon ultrafiltration device. Then the antibody can be purified by methods such as chromatography, dialysis and affinity purification. Protein A is suitable as an affinity ligand for the purification of IgGl, IgG2 and IgG4 antibodies. Other antibody purification methods, such as ion exchange chromatography, can also be used. After the antibody with sufficient purity is obtained, a formulation comprising the antibody can be prepared according to methods known in the art. For example, the preparation of an antibody by a down-stream processing (DSP) can be performed by the following steps: (1) removing impurities such as cells from fermentation broth by centrifuging and clarifying after the fermentation to give a supernatant; (2) capturing an antibody using affinity chromatography (e.g., a protein A column with specific affinity for IgGl, IgG2 and IgG4 antibodies); (3) inactivating viruses; (4) purifying (usually AEX and / or CEX cation exchange chromatography) to remove impurities from the antibody protein; (5) filtering the viruses (to reduce the virus titer by, e.g., more than 4 log 10); and (6) ultrafiltering / diafiltering (which can be used to allow the protein to be exchanged into a buffer that is favorable for its stability and concentrated to a suitable concentration). See, e.g., B. Minow, P. Rogge, K. Thompson, BioProcess International, Vol. 10, No. 6, 2012, pp. 48-57. In addition to chromatography purification, virus filtration and ultrafiltration are critical technologies that play unique roles in all antibody purification processes. See, e.g., Approaches to the Purification, Analysis and Characterization of Antibody-Based Therapeutics, 2020, Pages 137-166, Chapter 7 - Recent advances in ultrafiltration and virus filtration for production of antibodies and related biotherapeutics, https: / / doi.otx / 10.1016 / B978-0-08-103019-6.00007-2. Virus filtration (VF) is a unit operation used in the downstream process to assure the viral safety of biopharmaceutical products. Virus filtration is usually implemented near the end of the purification process, after the chromatography steps and prior to the ultrafiltration and diafiltration steps. The filtration removes both endogenous and adventitious viruses via size exclusion (viruses are retained and the drug product passes through). They provide additional value over added steps like virus inactivation (solvent / detergent treatment or low pH hold) because they do not leave viral material behind in the process stream. In some embodiments, virus filtration can be performed by using virus filters having specially-designed membranes with pores small enough to retain viruses while still allowing passage of the mAb product. Ultrafiltration / Diafiltration (UF / DF) is often employed at the end of the downstream process just prior to bulk drug substance formulation. However, ultrafiltration (UF) may be used prior to various chromatography steps to improve the efficiency of the chromatography. Ultrafiltration (UF) concentrates a dilute product stream and separates antibody molecules in solution based on the membrane pore size or molecular weight cutoff. Diafiltration (DF) 15 exchanges antibody products from an existing buffer into a new buffer for a following process or a final formulation buffer. In some embodiments, UF / DF can be performed by using tangential-flow filtration (TFF). In one aspect, therefore, the present disclosure provides a method for preparing the liquid antibody formulation according to the present invention, which include the steps of: (a) producing a drug substance (DS) from a mixture comprising the antibody by a downstream process (DSP), and (b) formulating the drug substance into the liquid formulation, preferably, the method further includes adding a chelating agent into at least one processing solution of the DSP at step (a). In an embodiment, the DSP includes at least one of protein A affinity chromatography, virus filtration (VF) and ultrafiltration and diafiltration (UFDF). In an embodiment, the DSP includes virus filtration (VF) and ultrafiltration and diafiltration (UFDF). In an embodiment, the DSP includes protein A affinity chromatography and ultrafiltration and diafiltration (UFDF). In an embodiment, the DSP includes protein A affinity chromatography, virus filtration (VF) and ultrafiltration and diafiltration (UFDF). In a further embodiment, the DSP further includes ion exchange chromatography. In an embodiment, the ultrafiltration and diafiltration (UFDF) is performed at the end of the downstream process just prior to the formulation of the drug substance. In an embodiment, the mixture comprising the antibody is a cell culture harvested from a mammalian host cell recombinantly expressing the antibody, which have or have not undergone various treatments, for example, one or more purification operations, such as one or more filtration steps, one or more chromatography steps, and any combination thereof. In another embodiment, the mixture comprising the antibody is a drug substance containing the antibody, which is to be reprocessed in order to for example concentrate and / or purify the antibody. Due to the pharmaceutical properties of an antibody, even seemingly simple operations like freezing or thawing drug substances could lead to formation of impurities and reduction in their quality attributes. Therefore, in some instances, it may be necessary to subject the drug substances to a reprocessing procedure when impurities, lower levels of purity, or reduced quality are detected. In an embodiment, the method according to the present invention includes adding a chelating agent into at least one processing solution of the DSP at step (a). In a preferable embodiment, the DSP includes at least one of a chromatography process (especially protein A affinity chromatography), a virus filtration (VF) process and a ultrafiltration and diafiltration (UFDF) process, and the chelating agent is added into the processing solution selected from the group consisting of chromatography pool, the VF pool and the UFDF pool. In a preferable embodiment, the processing solution with the addition of EDTA is used for a UFDF process to provide the DS. In a preferable embodiment, the UFDF process is performed by Tangential Flow Filtration (TFF). In a further preferable embodiment, the chelating agent is selected from the group consisting of EDTA, DTPA, their salts, and any combination thereof. In some embodiments, the chelating agent is in the form of a salt, such as alkaline earth or alkali metal salt, e.g., sodium salt. In a more preferable embodiment, the chelating agent is EDTA or its sodium salt. In a further preferable embodiment, the chelating agent is added into the processing solution in an effective amount to stabilize the liquid formulation according to the present invention. In a further preferable embodiment, the addition amount of the chelating agent is about 20pM to about 500pM, preferably about 30pM to about 200pM, about 30pM to about lOOpM e.g., 30pM, 35pM, 40pM, 45pM, 50pM, 55pM, 60pM, 65pM, 70pM, 75pM or more. In a more preferable, embodiment, the chelating agent is EDTA in the form of a salt, and the addition amount of the chelating agent is about 50pM. In an embodiment, the residue amount of the chelating agent in the DS produced by step (a) is about IpM to about lOOpM, preferably less than 50pM, more preferably less than 20pM or lOpM. As 16 appreciated by persons skilled in the art, in embodiments where a stabilizing effective amount of the chelating agent is included in the DSP, the residue amount of the agent in the DS may vary depending on the processing solution used for incorporation of the agent; nevertheless, the desired stabilizing effect can still be achieved. In some embodiments, the chelating agent is added into the UFDF pool at 30pM to about 60qM, especially at about 50pM. and the UFDF is performed by Tangential Flow Filtration. In some embodiments, the chelating agent is added into the VF pool at 30qM to about 60qM, especially at about 50qM. Use of Formulation The antibody formulation according to the present invention comprises the anti-Claudinl8.2 antibody that possess a therapeutic and / or prophylactic effect and can be used for treating or preventing anti-Claudinl8.2 antibody related disorder such as cancer in a subject in need thereof. See, WO2021 / 032157 and WO2023 / 088221, the disclosures of which are hereby expressly incorporated by reference. A “CLDN18.2-related” disease or condition as used herein refers to any disease or condition caused by, exacerbated by, or otherwise linked to increased or decreased expression or activities of CLDN18.2. In some embodiments, the CLDN 18.2 related condition is, for example, cancer. “Treating” or “treatment” of a condition as used herein includes preventing or alleviating a condition, slowing the onset or rate of development of a condition, reducing the risk of developing a condition, preventing or delaying the development of symptoms associated with a condition, reducing or ending symptoms associated with a condition, generating a complete or partial regression of a condition, curing a condition, or some combination thereof. The term "subject" as used herein includes human and non-human animals. Except when noted, the terms "patient" or "subject" are used herein interchangeably. In one aspect, therefore, the present disclosure provides the liquid antibody formulation according to the present invention or the solid antibody formulation according to the present invention for use in therapy, especially for use in treatment or prevention of anti-Claudinl8.2 antibody related disorder such as cancer. In another aspect, the present disclosure provides methods of treatment or prevention of anti-Claudinl8.2 antibody related disorder such as a cancer, by administering to a subject in need thereof an effective amount of the liquid antibody formulation according to the present invention or the solid antibody formulation according to the present invention. In another aspect, the present disclosure provides use of the liquid antibody formulation according to the present invention or the solid antibody formulation according to the present invention in manufacture of a medicament, especially a medicament for treatment or prevention of anti-Claudin 18.2 antibody related disorder such as a cancer. Preferably, the subject is a mammal, especially a human. In sone embodiments, the cancer is selected from gastric cancer, lung cancer, bronchial cancer, bone cancer, liver and bile duct cancer, pancreatic cancer, breast cancer, liver cancer, ovarian cancer, testicle cancer, kidney cancer, bladder cancer, head and neck cancer, spine cancer, brain cancer, cervix cancer, uterine cancer, endometrial cancer, colon cancer, colorectal cancer, rectal cancer, anal cancer, esophageal cancer, gastrointestinal cancer, skin cancer, prostate cancer, pituitary cancer, stomach cancer, vagina cancer, thyroid cancer, glioblastoma, astrocytoma, melanoma, myelodysplastic syndrome, sarcoma, teratoma, and adenocarcinoma. In some embodiments, the cancer is a digestive cancer, e.g., gastric cancer (GC), gastroesophageal junction (GEJ) cancer, esophageal cancer, or pancreatic cancer. In some embodiments, the subject is identified as having a CLDN18.2-expressing cancer cell. In certain embodiments, the expression of CLDN18.2 in the cancer cell from the subject is determined or measured by Immunohistochemistry (IHC). In some embodiments, the subject is identified as having CLDN18.2 high-expressing cancer cells, CLDN18.2 medium-expressing cancer cells, or CLDN18.2 low-expressing cancer cells. In certain embodiments, the CLDN18.2 high-expressing cancer cells express CLDN18.2 at an intensity of at least 2+ as measured by IHC and at a level where at least 40% (e.g. at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, 40-100%, 50-100%, 60100%, 70-100%, 80-100%, 90-100%, 40-90%, 50-90%, 60-90%, 70-90%, 80-90%, 40-80%, 40-70%, 40-60%, 4050%, 50-80%, 50-70%, 50-60%, 60-80%, 60-70%, or 70-80%) of the cells are stained positive in IHC; the mediumexpressing cancer cells express CLDN18.2 at an intensity of at least 1+ and below 2+ as measured by IHC and at a level where at least 30%(or at least 35%) but below 40%of the cells are stained positive in IHC; and the low-expressing cancer cells express CLDN18.2 at an intensity of above 0 but below 1+ as measured by IHC and at a level where above 0 but below 30% (e.g. 5%, 10%, 15%, 20%, 25%, 5-25%, 10-25%, 15-25%, 20-25%, 5-20%, 515%, 5-10%, 10-20%, or 10-15%) of the cells are stained positive in IHC. The antibody formulation according to the present invention can be administered to a subject or a patient in a variety of routes, including but not limited to oral, nasal, intravenous, subcutaneous, sublingual, or intramuscular administration. For example, the administration can be performed by infusion or by using a syringe. The effective amount or therapeutically effective amount of the antibody for any specific subject will depend on a variety of factors including the age, weight, health status and / or sex of the patient, the nature and extent of the disease, the activity of the specific antibody, its clearance in the body, as well as any other possible treatments administered in combination with the antibody formulation. For a specific case, the effective amount delivered can be determined based on the judgment of a clinician. In some embodiments, a second therapeutical agent is administered in combination with the anti-Claudinl8.2 antibody in the same or separate formulation. In some embodiments, the second therapeutic agent is selected from a chemotherapeutic agent, an anti-cancer drug, radiation therapy, an immunotherapy agent, anti-angiogenesis agent, a targeted therapy agent, a cellular therapy agent, a gene therapy agent, a hormonal therapy agent, or cytokines. In some embodiments, the second therapeutic agent is anti-PDl. In some embodiments, the antibody formulation is for use in injection, optionally subcutaneous, intravenous or intramuscular injection. In some embodiments, the liquid antibody formulation is an infusion, e.g., for intravenous infusion. In some embodiments, the antibody formulation is for subcutaneous injection. Accordingly, in one aspect, the present invention provides a delivery device comprising the antibody formulation according to the present invention. The patient will receive an effective amount of the antibody as the primary active ingredient, i.e., an amount sufficient to treat, ameliorate or prevent the disease or disorder of interest. In some embodiments, the device is syringe, or a pre-filled syringe. In another aspect, the present disclosure provides a vial for subcutaneous injection comprising the liquid antibody formulation according to the present invention or the solid or reconstituted antibody formulation according to the present invention. Abbreviations Abbreviations used in the present application are provided in Table 1. Table 1 Abbreviations Abbreviation Full name DS Drug Substance D Day W Week M Month PD% Polydispersity index DSP Downstream Process rpm Revolutions per Minutes PFS Pre-filled Syringe SubQ Subcutaneous UFDF Ultrafiltration and Diafiltration Visual Visual examination Cone. Concentration Osmo. Osmolarity Ace Acetic acid / Sodium Acetate Buffer System His L-Histidine / Histidine HC1 Buffer System DLS Dynamic Light Scattering PVDF Polyvinylidene Fluoride TFF Tangential Flow Filtration UV Ultra Violet HPLC High Performance Liquid Chromatography HMW High Molecular Weight LMW Low Molecular Weight SEC Size Exclusion Chromatography NR-CE Non-reduced Capillary electrophoresis-sodium dodecyl sulfate CEX Cation Exchange Chromatography MP Main peak AP Acidic Peak BP Basic Peak PS80 Polysorbate 80 ND No Detected NT Not Tested NA Not Applicable CC Clear and Colorless soc Slightly Opalescence and Colorless EXAMPLES The recombinant anti-Claudinl8.2 monoclonal antibody used in the Examples comprises a high chain as shown in SEQ ID NO: 3 and a light chain as shown in SEQ ID NO: 4. The sequences of the antibody are also shown in the Sequence Listing submitted with the present application. In order to develop a stable liquid formulation of high-concentration anti-Claudinl8.2 antibody, the effects of various excipients, as well as the downstream process, on the antibody’s multiple quality attributes were investigated in accelerated stability studies at about 25 °C, forced stability studies at about 40 °C, and long-term stability studies at about 5-8 °C. The materials and methods used in the Examples are as follows: Materials and Methods Materials Table 2. Equipment Equipment Name Vendor Model Analytical Balance Mettler Toledo ML204T / 02 pH Meter Mettler Toledo Seven Compact S220 UV Spectrophotometer Thermo Scientific Nano Drop 2000 Clarity Detector Tianda Tianfa YB-3 DynaPro Plate Reader-II(DLS) WYATT WPR2-09 Refrigerator Haier HYC-1378 Clean Bench AIRTECH VS-1300L-U Stability Chamber Memmert HPP400 Stability Chamber Memmert ICH110L Ultra-pure Water Purifier Millipore Milli-Q Advantage A10 Shaker for Agitation HDL Apparatus (Harbin, China) HZQ-F160 Table 3. Consumables Vendor Product No. Specification PVDF Membrane Millipore SLGVR33RS 33mm, 0.22pm PVDF Membrane Millipore SLGV013SL 13mm, 0.22pm PES Membrane Millipore SLGP033RS 33mm, 0.22pm Slide-A-Lyzer® Dialysis Cassette Thermo 66012 20K MWCO, 3.0-12 mL Centrifugal Filter Units Millipore UFC803096 30K Injection Vial Schott Glass Technologies 1542306 2mL, neutral borosilicate glass (RTU) Stopper for Injectable Sterile Powder West Pharma Packaging 7002-0664 13mm Flurotec, B2 coating Blue Aluminum Cap West Pharma Packaging 5413-3001 13 mm Table 4. Reagent Reagent Name Grade Vendor Product No. L-Histidine EMPROVEexp, Ph Eur, USP, JP Merck 1.04352.1000 L-Histidine Mono- hydrochloride Monohydrate EMPROVEexp, Ph Eur, BP, JP Merck 1.04354.0500 Sodium Acetate Trihydrate EMPROVEbio, Ph Eur, USP, BP, JP Merck 1.37012.1000 Glacial Acetic Acid USP J.T Baker UN2789 Polysorbate 80 ChP, USP Croda SR40925 Sucrose NF, EP, JP, ChP, High Purity, Low Endotoxin, Beet Derived Pfanstiehl S-124-2-MC Arginine hydrochloride EMPROVEexp, Ph Eur, USP, JP Merck 1.01587.1000 Sodium Chloride EMPROVEexp, Ph Eur, BP, JP, USP Merck 1.16224.5000 L-Proline Ph.Eur., USP Merck 1.07430.1000 Titriplex III (EDTA-2Na) Ph Eur, BP, JP, USP, ACS Merck 1.37004.1000 Methods Preparation of Drug substance (DS) of antibody DS of anti-Claudinl8.2 antibody is prepared substantially as described in Examples of WO2021 / 032157 (incorporated herein for reference). The nucleic acids encoding the heavy chain and the light chain of the antibody are transfected into CHO host cells. The cell culture supernatant is harvested and filtered to remove cell debris, and then purified by downstream processing including protein A affinity chromatography, ion-exchange chromatography and virus filtration. The purified antibody is concentrated and exchanged into a buffer by ultrafiltration / diafiltration (UF / DF) to provide the DS for formulation. Buffer System preparation All buffer solutions are prepared using acidic and basic ion pairs. The process involves the following steps. Accurately weigh the excipients that provide acidic and basic ion pairs, add about 60% Milli-Q water of the specified buffer volume, mix evenly, and measure the pH of the solution. If the pH value deviates from the target value, use the corresponding ion pairs to adjust the pH. Once the desired pH is achieved, dilute the solution with Milli-Q water to the final weight or volume. Finally, measure the conductivity, osmolarity and pH of the solution for verification. Formulation preparation Drug substance (DS) of the antibody is buffer exchanged into a target formulation by dialysis. Alternatively, a high-concentration excipient stock solution is directly added into a concentrated DS solution, and then the DS solution is diluted to the desired concentration using the buffer system of interest to produce the target formulation. Dialysis Dialysis is performed using the Slide-A-Lyzer cassette following the manufacture’s recommendation. A 3-12 mL sample is loaded into the cassette along the wall, and then the cassette is immersed into the target formulation buffer with a volume of approximately 100 to 200 times the sample volume. The cassette is equilibrated for 3 hours at room temperature and with stirring at 150rpm, and then transferred to a fresh buffer and left to equilibrate overnight. After the overnight incubation, the buffer is replaced with fresh buffer, and the cassette is equilibrated for another 3 hours. Visual inspection The appearance and visible particles of a formulation are examined against black background by a YB-3 clarity detector. The clarity and the color of the formulation are reported. In addition, meeting the standard for visible particles is reported when the formulation is determined to be essentially free of visible particles according to the definition outlined in the Chinese and U.S. Pharmacopoeia. Micro-Flow Imaging (MFI) Flow microscopy is applied to sub-visible particulate analysis in protein formulations. Take 1 mL sample for injection using a pipette without dilution. Report the number of particles per mL in the size range of > 2 pm, >10 pm, and > 25 pm. pH measurement The pH of a sample is measured by a SevenCompact S220 pH meter equipped with an Inlab® Expert Pro electrode. The pH meter is calibrated prior to use. Determination of Protein Concentration Protein concentration is determined by measuring the absorbance at 280 nm using a Nano Drop 2000 spectrophotometer. The extinction coefficient (El%) used is 1.511 L / g-cm throughout the study. Each sample is measured twice at a loading volume of 2.0 pL. The average concentration is reported. Since the instrument is sensitive, a high concentration sample needs to be diluted to a level below 50mg / mL in order to obtain more reliable data. Dilution is performed by gravimetric approach. The concentration of the sample before dilution is determined based on the weight ratio of the sample to the water added. Dynamic Light Scattering (DLS ) Protein size distribution is determined by DLS using Wyatt DynaPro Plate Reader-II with a 5 seconds acquisition time, 20 acquisitions per measurement at 25°C. The DLS measurement provides the hydrodynamic radius and the polydispersity index (PD%). Additionally, the DLS can be used to reveal the information about colloidal stability through the diffusion interaction parameter (kn). kn is measured by the slope of DLS measured diffusion coefficient Dt against the protein concentration. Viscosity measurement Protein viscosity is determined by using m-VROC™ Viscometer (RheoSense) with a 3 s-1 shear rate in water bath at 25 °C. Size Exclusion Chromatography (SEC) Protein aggregation is determined by SEC using a Waters H Class system and an Agilent AdvanceBio column (4.6x150mm mm, 1.9 pm). The mobile phase is 50 mM phosphate buffer (PB), 300 mM NaCl, pH 6.8 ± 0.1. The flow rate is 0.4 mL / min. Samples are diluted to 2.0 mg / mL, loaded at 10 pL and detected at 280 nm. Cation-Exchange Chromatography (CEX ) Charge heterogeneity of protein is determined by CEX using a Thermo Propac™ Elite WCX-10 HPLC column (4mm x 150mm, 5pm) in an Agilent 1260 Infinity system. Samples are diluted to 2.00 mg / mL with the mixed solution of mobile phase A and B. Mobile phase A is 20mM phosphate buffer. Mobile phase B is 20mM phosphate buffer and 0.15M sodium chloride. Non-reduced Capillary electrophoresis-sodium dodecyl sulfate (NR CE-SDS) Protein fragmentation is determined by NR CE-SDS. Samples, along with the reference standard (DS protein), are diluted to 4 mg / mL with N-ethylmaleimide (NEM) and SDS sample buffer, and then denatured at 70±2°C for 10+2 minutes and centrifuged at 13000rpm for 1 minute. Separation of sample components is performed on PA800 plus using a SDS separation gel and an uncoated capillary (Beckman Coulter). Potency assay The bioactivity assay for antibody product is a cell-based potency assay based on a bioluminescent reporter gene and the mechanism of action of ADCC (short for antibody-dependent cell-mediated cytotoxicity). ADCC is a major mode of action of therapeutic monoclonal Abs (mAbs). The immune reaction relies on the dual activities of mAbs: the Fab of antibodies bind to antigen, and the Fc region of the same antibodies bind to Fc receptor of effector cells. ADCC is mediated by Natural Killer (NK) cells which express FcyRIIIA (CD16A), an activating IgG receptor. Cross-linking of FcyRIIIA at the surface of NK cells triggers downstream signaling. The readout of the fluorescence signal is positively proportional to the ADCC activity. The dose response curves are fitted using a 4-parameter logistic (4PL) model. The results are reported as Relative Potency, using the calculation formula: Relative Potency (potency%) = (EC50 of Sample / EC50 of Reference Standard) * 100%. Stability study Samples are placed in stability chambers set at 40°C and 25°C for the forced / accelerated studies. In addition, depending on the sample type and the study protocol, samples are placed in a refrigerator set at 5-8°C for long-term stability studies. Agitation study The sample containers are securely positioned horizontally on the tray of the shaker. The shaker is set at an agitation rate of 200rpm and a temperature of 25°C. During the agitation study, the samples are agitated in the dark for a predetermined duration. Example 1: Viscosity Study 1. Study Design In this study, high concentration formulations were investigated, which are intended for a PFS (pre-filled syringe) dosage form that is administered via SubQ (subcutaneous) injection. SubQ injection formulations typically require controlling the injection volume within the range of 1ml to 2mL. As a result, increasing the protein concentration in these formulations becomes necessary to ensure adequate dosage for treatment. However, higher protein concentration often leads to a significant rise in viscosity. Therefore, a viscosity study needs to be conducted to facilitate the future manufacture, filling, and administration of drug products. The primary objective of this study was to quickly establish the correlation between viscosity and antibody concentration in the early stage of drug development. This correlation would aid in determining a suitable protein concentration, and provide support for the subsequent development of high concentration formulations. In the meanwhile, this study aimed to screen for excipients capable of reducing protein viscosity, and select a formulation for stability testing. The drug substance (DS) of the antibody was concentrated through ultrafiltration using a centrifuge to the maximum operable concentration. Then, buffer and excipient stock solution were added into the DS to prepare the formulations in Table 5, and the viscosity of the formulations was measured. Table 5. Viscosity Study Design Formulation Protein Conc.(mgZmL) Buffer Excipient conditions Test Items Fl 200 10 mM Ace, pH5.3 NA TO Cone., Viscosity F2 170 7% Sucrose, 0.02% PS80 F3 (Ace-i- Sue) 150 TO Visual, DLS, Cone., pH, SEC, CEX, NR-CE, PS80, Osmo, Viscosity 40°C:2W&4W 25°C:2W&4W DLS, SEC, CEX, PS80(40C2W) NR-CE (25C4W&40C4W) Potency(40C4W) Agitation 7D DLS, Cone., SEC, MFI F4 (Ace+Pro) 230mM Proline, 0.05% PS 80 TO Visual, DLS, kD, Cone., pH, SEC, Osmo, Viscosity F5 (His+Suc) 10 mM His, pH5.3 5.5% Sucrose, 0.05% PS80 F6 (Ace+Suc+ NaCl) 10 mM Ace, pH5.3 5.5% Sucrose, 50mM NaCl, 0.05% PS80 F7 (Ace+Suc+ Arg-HCl) 5.5% Sucrose, 50mM Arg- HC1, 0.05% PS 80 *T0 refers to the time before the start of the stress treatment 2. Study Results According to the designed experimental conditions, 7 different formulations were investigated and sampled for testing. The TO results of 7 formulation samples are shown in Table 6. The results of the formulation F3 under stress conditions of 25°C, 40°C, and agitation are shown in Table 7. Table 6. Viscosity Study Result Summary-TO Sampling Point Formulation bibibib IBBBOBBBB^ IBBBOBBBB^ Appearance NA NA soc SOC SOC SOC SOC Visible Particle NA NA Meet the standard Protein Cone. (mg / mL) 201 168 164 159 154 166 175 Osmo. (mOsm / kg H2O) NA NA 290 373 292 272 266 pH NA NA 5.5 5.5 5.6 5.5 5.5 Viscosity (mPa-s) undiluted 37.5 19.4 14.9 9.5 11.3 12.1 11.6 Diluted to 120mg / mL NA NA NA 4.5 5.0 5.0 4.8 colloidal stability kD(mL / mg) NA NA 3.95*10-2 5.34*10-2 2.81*10-2 3.34*10-4 9.50*10-4 DLS Radius(nm) NA NA 2.6 2.3 3.3 7.5 6.5 PD% NA NA 12.9 19.5 26.3 11.2 21.5 SEC HMW% NA NA 1.9 1.9 2.1 2.2 1.8 MP% NA NA 97.8 97.8 97.7 97.5 97.9 LMW% NA NA 0.3 0.2 0.2 0.2 0.2 Table 7. Viscosity Study Result Summary-F3 under stress conditions Time Point iiiiiiiiiiiiiiiiii iiiiiiiiiiiiiiiiiiii IllOilll ibbbbiwbbbbb BBBB^IWBBBB^ DLS Radius(nm) 2.6 2.7 2.8 2.8 2.8 2.3 PD% 12.9 13.8 16.5 19.5 15.3 20.1 SEC HMW% 1.9 4.2 3.0 7.9 5.6 NT* MP% 97.8 95.1 96.6 90.4 92.4 LMW% 0.3 0.6 0.4 1.7 2.0 CEX AP% 20.9 21.5 22.9 44.3 57.5 NT MP% 57.8 57.6 57.1 39.3 27.6 BP% 21.4 21.0 20.0 17.4 14.9 NR CE MP% 96.3 NT 95.6 NT 87.3 NT LMW% 3.1 3.5 10.3 Potency% NT NT NT NT 91 NT *: The A7D sample (i.e., sample subjected to 7-day agitation) was not sent for test because the haze particles were observed by visual inspection. 3. Analysis and Discussion (1) The viscosity results of the formulations Fl and F2 at TO in Table 6 showed that the viscosity increased sharply as the protein concentration in the sample increased. Additionally, the TO results of formulations F3 to F7 showed that Formulation F4 (acetic acid buffer system plus proline) and Formulation F5 (Histidine buffer system plus sucrose) had a lower viscosity. It is widely accepted that when the viscosity of protein products exceeds the injection limit (typically not exceeding 20mPa-s for subcutaneous injection solutions), it becomes very difficult to administer them through a syringe. Therefore, based on the preliminary analysis, the protein content set at or lower than 150mg / mL is acceptable for viscosity aspect. (2) The data of formulation F3 in Table 7 showed that, at a concentration of about 150mg / mL, there was no significant change observed in the main peaks as measured by CEX and NR-CE at 25°C. However, SEC HMW% had a noticeable increase at 25°C; and a rapid degradation of the SEC, CEX and NR-CE main peaks occurred at 40°C. In addition, it was observed that during agitation, a relatively large number of visible particles appeared, which may be due to the low content of PS80. In view of the above results, the two formulations, F4 and F5, with lower viscosity were selected for further formulation study, while reducing the protein concentration and increasing the content of PS80 in the formulations. Example 2: Formulation Optimization Study 1. Study Design In the formulation optimization study, the two formulations F4 and F5 in Example 1 were further investigated, with antibody concentration reduced to about 120mg / ml. Due to the antibody concentration reduced to about 120mg / ml, the Sucrose concentration was increased to 7.5% for getting the osmotic pressure around 300 (mOsm / kg H2O). In addition, a set of low concentration formulations were included in the study to compare the effects of serially diluted antibody concentrations on the formulation stability. Furthermore, given that the significant increase in visible particles observed in the agitated samples of F3 formulation in Example 1, the content of PS80 was increased from 0.03% to 0.05% in the F4 and F5 formulations to be tested to protect the protein against shear forces during agitation. The formulations in Table 8 were prepared by adding buffer systems and excipient stock solutions to a concentrated DS solution. The samples were filtered through 0.22 pm PVDF membrane and were aliquoted into 2mL vials using pipettes. And then all samples were subjected to the stability studies as indicated in Table 8. Table 8. Study Design of Formulation Optimization Study Formulation Protein Buffer system Excipient conditions Test Items F8 120 lOmM Acetate, pH 5.3 230mM Proline, 0.05% PS80 TO 25°C:2W&4W 40°C:2W&4W Agitation 7D Visual, DLS, Cone., pH(T0), Osmo(TO), SEC, CEX, NR-CE, PS80(40C), Viscosity(TO), MFI( Agitation) F9 120 lOmM Histidine, pH 5.3 7.5%(w / v) Sucrose, 0.05% PS80 F10 120 lOmM Acetate, pH 5.3 Fil 100 TO 25°C:2W&4W 40°C:2W&4W F12 60 F13 30 2. Study Results (1) Results at TO The results obtained on the six formulations F8 to F13 at TO are summarized in Table 9. At TO, all the F8-F13 formulations were observed to be a colorless and clear liquid, with no visible particles. Among the formulations F8 to F10 which had about the same protein concentrations, F8 comprising the combination of proline and acetic acid buffer system was observed to have the lowest viscosity. The formulations Fil-Fl 3, which had the same formulation design but a lower antibody concentration compared to F10, exhibited a decrease in both osmolarity and pH, as expected. Table 9. Result Summary of Formulation Optimization Study-TO Formulation BIBBIBBBBB OIBBMBBBB FI0 Fil BBBMIBBB^ BBBMBBBB^ Appearance cc cc CC CC cc cc Visible Particle Meet the standard Protein Cone. (mg / mL) 120.4 118.9 121.7 98.6 61.3 29.4 Osmo.(mOsm / kg H2O) 330 347 331 322 282 261 PH 5.3 5.1 5.2 5.2 5.1 4.9 Viscosity (mPa-s) 4.3 5.6 5.5 3.8 2.1 1.5 (2) Accelerated (25±2°C / 60±5 % RH) experiment results Accelerated stability study was conducted to examine the changes in relevant quality attributes of the samples stored at 25±2°C and 60 + 5% RH, with the aim of preliminarily determining the stability of the samples under room temperature condition. The summary of accelerated experiment results is shown in Table 10. Within 4 weeks of incubation at 25 °C, no significant changes were observed in the protein concentration, appearance and visible particles of all formulations, and they all met the standards for release and shelf-life. The protein radius of each formulation remained basically unchanged during the incubation, but the radius of F9 containing histidine buffer system was slightly larger than that of the other formulations containing acetic acid buffer system. After the incubation, as measured by SEC, the HWM level of formulations F8-F11 showed minimal changes, and the HWM level of formulations F12 / F13 which had lower protein concentrations remained unchanged or showed a decreasing trend. In addition, it was observed in all formulations that the MP purity as measured by CEX and the LMW level as measured by NR CE remained basically unchanged during the incubation, but with F9 showing a faster degradation trend in the MP purity, and F8 showing a faster trend in fragmentation. Table 10. Result Summary of Formulation Optimization Study-25±2°C / 60±5 %RH Formulation OBBBBBBBBBBBMBBBBBBBBBBBB F10 BBBiiBB^ BB^ilBB^ BB®BB^ OBBiiBBB BB^®BB^ BB®BB^ BBBiiBBB BB^ilBB^ BBOBB^ Appearance cc cc cc cc cc cc cc cc cc Visible Particle Meet the standard Protein Cone. (mg / mL) 119 121 125 122 119 121 120 121 122 DLS Radius(nm) 1.9 2.0 2.0 2.8 2.9 3.0 2.3 2.4 2.4 PD% 14.5 22.7 19.7 30.7 32.5 30.9 16.0 27.3 17.5 SEC HMW% 1.1 1.2 1.3 1.1 1.1 1.3 1.1 1.3 1.6 MP% 98.8 98.6 98.3 98.7 98.6 98.4 98.7 98.5 98.1 LMW% 0.2 0.2 0.3 0.2 0.2 0.3 0.2 0.2 0.3 CEX Acid% 21.0 22.0 21.9 20.9 21.6 21.4 21.0 21.9 21.9 MP% 57.6 57.6 57.3 57.7 57.4 56.7 57.6 57.7 57.2 Basic% 21.4 20.3 20.8 21.4 20.9 21.9 21.4 20.4 20.8 NR-CE MP% 96.0 NT 94.9 96.7 NT 96.1 96.6 NT 95.9 LMW% 3.6 NT 4.6 3.0 NT 3.5 3.1 NT 3.5 Formulation Fl 1 BBBWBB^ BBOBB^ BBMBB^ OBBiiBBB BBOBB^ BBMBB^ BBBWBBB BBOBB^ BB^ilBB^ Appearance cc cc cc cc cc cc cc cc cc Visible Particle Meet the standard Protein Cone. (mg / mL) 99 99 102 61 61 60 29 29 31 DLS Radius(nm) 2.1 2.2 2.3 1.9 2.0 2.1 2.2 2.2 2.2 PD% 12.4 22.0 27.5 9.0 22.7 26.4 19.0 13.2 13.8 SEC HMW% 1.0 1.1 1.3 0.8 0.8 0.8 0.8 0.7 0.5 MP% 98.8 98.6 98.4 99.0 98.9 98.9 99.1 99.1 99.2 LMW% 0.2 0.2 0.3 0.2 0.2 0.3 0.2 0.3 0.3 CEX Acid% 20.9 22.0 22.1 21.0 22.1 22.2 21.0 22.2 22.3 MP% 57.7 57.7 57.2 57.7 57.8 57.3 57.8 57.8 57.1 Basic% 21.3 20.3 20.7 21.3 20.1 20.5 21.2 20.0 20.6 NR- MP% 96.8 NT 96.0 96.8 NT 96.1 96.8 NT 96.1 CE LMW% 3.0 NT 3.6 3.0 NT 3.6 3.0 NT 3.7 (3) Forced degradation (40±2°C / 75±5 % RH) experiment results Forced degradation stability study was conducted to examine the changes in relevant quality attributes of the samples stored at 40±2°C and 75 ± 5% RH, with the aim of preliminarily determining the stability of the samples under high temperature and high humidity condition. The forced degradation experiment results are summarized in Table 11. Within 4 weeks of incubation at 40 °C, no significant changes were observed in the protein concentration, appearance, and visible particles of all the formulations, and they all met the standards. The protein radius of each formulation remained basically unchanged during the incubation, with the particle radius of F9 still slightly larger than that of the other formulations containing acetic acid buffer system. For the SEC results, the HMW of all formulations increased with incubation, but to varying degrees. F12 / F13 with lower protein concentration showed slower trends of HMW increase during incubation, whereas F10 demonstrated a relatively faster increase in HMW (an increase of 3.3% at 4 weeks), which although remained within the acceptable range. For the CEX results, the MP purity of all formulations experienced rapid degradation during the incubation, and there was no significant difference observed among the different formulations. For the NR CE results, all formulations showed rapid degradation of the MP and formation of fragments during incubation, with F8 showing the fastest increase in LMW (an increase of 9.2% at 4 weeks), while there was no significant difference in LMW among the remaining formulations. For the PS80 content analysis, all formulations showed rapid degradation of PS80, with the level reducing to 0.01% at 4 weeks of incubation. For the potency results, all formulations, as detected in the samples incubated for 4 weeks, remained within an acceptable range. Table 11. Result Summary of Formulation Optimization Study-40±2°C / 75±5 % RH Formulation )))))))))))))))))))))) ((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((11((((((((((((((((((((((((((((((((((((((((((((((((((((((((((( FI0 TO iii(ii(i (((((((((((((11((((((((((((( TO (((((((((((((11((((((((((((( ((((((((((((((11((((((((((((( TO (((((((((((((11((((((((((((( (((((((((((((11((((((((((((( Appearance CC CC CC CC CC CC CC CC CC Visible Particle Meet the standard Protein Cone. (mg / mL) 119 124 125 122 119 121 120 122 123 DLS Radius(nm) 1.9 2.1 2.1 2.8 3.2 3.1 2.3 2.5 2.6 PD% 14.5 13.1 19.5 30.7 35.7 31.3 16.0 11.0 16.8 SEC HMW% 1.1 2.5 3.5 1.1 2.2 3.2 1.1 2.9 4.4 MP% 98.8 96.7 95.1 98.7 97.0 95.4 98.7 96.3 94.3 LMW% 0.2 0.8 1.4 0.2 0.8 1.4 0.2 0.8 1.3 CEX Acid% 21.0 41.2 53.7 21.0 35.2 46.9 20.0 40.1 53.6 MP% 57.6 41.5 30.0 57.6 44.1 33.7 57.7 42.4 29.9 Basic% 21.4 17.3 16.3 21.4 20.6 19.4 21.4 17.5 16.6 NR-CE MP% 96.0 NT 85.8 96.7 NT 88.6 96.6 NT 87.3 LMW% 3.6 NT 12.8 3.0 NT 10.1 3.1 NT 10.8 PS80% 0.04 NT 0.01 0.04 NT 0.01 0.04 NT 0.01 Potency% NT NT 82 NT NT 95 NT NT 99 Formulation Fl I (((((((((((((((((((((((((((((((((((((((((((((((((((((((((1(1(1((((((((((((((((((((((((((((((((((((((((((((((((((((((((( (((((((((((((((((((((((((((((((((((((((((((((((((((((((((11(1((((((((((((((((((((((((((((((((((((((((((((((((((((((((( (((((((((((((11((((((((((((( ((((((((((((((H((((((((((((( (((((((((((((((11((((((((((((((( (((((((((((((11((((((((((((( ((((((((((((((H((((((((((((( (((((((((((((((11((((((((((((((( (((((((((((((11((((((((((((( ((((((((((((11((((((((((((( Appearance CC CC CC CC CC CC CC CC CC Visible Particle Meet the standard Protein Cone. (mg / mL) 99 105 101 61 64 60 29 29 30 DLS Radius(nm) 2.1 2.4 2.4 1.9 2.1 2.2 2.2 2.2 2.4 PD% 12.4 21.7 22.5 9.0 29.0 27.6 19.0 12.0 18.4 SEC HMW% 1.0 2.4 3.7 0.8 1.7 2.8 0.8 1.0 2.0 MP% 98.8 96.8 94.9 99.0 97.5 95.8 99.1 98.1 96.4 LMW% 0.2 0.8 1.3 0.2 0.9 1.5 0.2 0.9 1.6 CEX Acid% 20.9 40.2 53.8 21.0 42.4 57.4 21.0 41.9 58.6 MP% 57.7 42.6 30.1 57.7 41.2 28.0 57.8 41.9 27.3 Basic% 21.3 17.2 16.0 21.3 16.4 14.6 21.2 16.3 14.1 NR-CE MP% 96.8 NT 88.1 96.8 NT 88.4 96.8 NT 88.9 LMW% 3.0 NT 10.2 3.0 NT 10.5 3.0 NT 10.8 PS80% 0.04 NT 0.01 0.04 NT 0.01 0.04 NT 0.01 Potency% NT NT 81 NT NT 86 NT NT 61 (4) Agitation experiment results The agitation stability study was conducted to examine the changes in relevant quality attributes of the samples placed at 200rpm, 25 °C, with the aim of preliminarily determining the tolerance of the samples to shear force. The results of the agitation study are summarized in Table 12. After 7 days of agitation stress, it was observed that there was no significant change in the appearance of the samples of the three formulations F8 to F10. For the visible particle results, F8 and F9 each had one newly added particle after the stress treatment, although the results were still better than those obtained in F3. The DLS results showed that the protein particle size of all three formulations remained basically unchanged, with an increase of less than 0.2nm. The MFI results demonstrated that the content of the sub-visible particles in all three formulations was kept at a relatively low level. Table 12. Result Summary of Formulation Optimization Study-200rpm, 25°C Formulation lllllllllliiBBBBBBBBB F10 IBBiBiiiBiBi^ BBiB^lBi^lBBi TO BBiB^HlBiBi^ IBBiBiiiBiBi^ BBiBUlBiBi^ Appearance cc cc CC cc cc cc Visible Particle Meet the standard Protein Cone. (mg / mL) 120.4 122.6 118.9 120.3 121.7 120.4 DLS Radius(nm) 1.9 2.0 2.8 3.0 2.3 2.4 PD% 14.5 17.2 30.7 24.2 16.0 23.2 SEC HMW% NT 254 NT 503 NT 41 MP% 40 4 4 LMW% 9 2 0 3. Analysis and Discussion According to the NR CE results, Proline was excluded from consideration because the addition of this excipient may cause a rapid increase in fragmentation of the protein molecule. Acetic acid buffer system and Histidine buffer system have basically the same protective effect on the protein. However, according to the DLS results, when Histidine system was chosen, the radius of the protein molecule was larger and its structure was looser. Consequently, F9 containing Histidine system was excluded from consideration. Formulation F10 was selected for further study, and based on the Osmolarity results of the F10 at TO, the sucrose concentration in the F10 was adjusted to 7.0% in order to reduce the final Osmolarity in the formulation to about 300 mOsm / kg H2O. Example 3: Formulation Confirmation Study 1. Study Design According to the formulation optimization experiment, the optimal formulation consisting of lOmM acetic acid buffer system pH5.3, 7% (w / v) sucrose, and 0.05% PS80 was selected for the formulation confirmation study. In addition, another formulation was developed by incorporating disodium Ethylenediaminetetraacetic acid (EDTA-2Na) into the optimal formulation to explore the impart of a chelator on slowing down the degradation of PS80. The formulations F14 and F15 listed in Table 13 were prepared by adding buffer systems and excipient stock solutions to a concentrated DS solution. Finally, the samples were filtered through 0.22 pm PVDF membrane and were aliquoted into 2mL vials using pipettes. And then all samples were subjected to the stability study as indicated in Table 13. Table 13. Study Design of Formulation Confirmation Study Formulation Protein Buffer system Excipient condition Test Items F14 120mg / mL lOmM Acetate, pH 5.3 7.0%(w / v) Sucrose, 0.05% PS80 TO 5°C:1&3M 25°C:2 / 4 / 6 / 8W 40°C:2 / 4 / 6 / 8W Visual, DLS, Cone., pH(T0), Osmo(TO), SEC, CEX, NR CE (TO, 25C / 40C 4W), PS80(T0, 40C), Viscosity(TO) F15 120mg / mL 7.0%(w / v) Sucrose, 0.05% PS80, 50pM EDTA-2Na 1. Study Results (1) Results at TO As shown in Table 14, at TO, both F14 and F15 showed colorless clear liquid, with no visible particles, and their protein content, pH and Osmolarity were all within the acceptable ranges. There was no significant difference in viscosity results between the two formulations. Table 14. Result Summary of Formulation Confirmation Study-TO Formulation BiBiBiBiBBiBiBiBiBi^ Appearance cc cc Visible Particle Meet the standard Protein Cone. (mg / mL) 117.5 124.2 Osmo.(mOsm / kg H2O) 309 298 pH 5.3 5.3 Viscosity (mPa-s) 5.4 5.4 (2) Long term experiment result 5±3°C Long term stability study was conducted to examine the changes in relevant quality attributes of the samples stored at 5±3°C, with the aim of preliminarily determining the stability of the samples under long term storage condition. The summary of the long-term experiment results is shown in Table 15. As shown in Table 15, within 3 months of incubation at 5°C, no significant changes were observed in the protein concentration, appearance, and visible particles of the two formulations, and they all met the standards. The protein radius of each formulation remained basically unchanged during the incubation. For SEC, CEX, and NR CE results, no significant changes were observed compared to TO, and there were almost no observed differences between the two formulations. Table 15. Result Summary of Formulation Confirmation Study-5±3°C Formulation BBBBBBBBBiiiiBBBi^ BBBBBBBBBBiiiBBB TO IBslWiB^ BBOBB^ TO BB^lBBis Appearance CC cc cc CC cc cc Visible Particle Meet the standard Protein Cone. (mg / mL) 117.5 115.0 119.6 124.2 119.4 119.0 DLS Radius(nm) 2.4 2.4 2.4 2.4 2.3 2.5 PD% 27.5 24.7 21.0 25.3 18.4 21.7 SEC HMW% 1.2 1.3 1.3 1.2 1.2 1.3 MP% 98.6 98.5 97.6 98.6 98.6 97.6 LMW% 0.2 0.2 1.2 0.2 0.2 1.2 CEX Acid% 21.8 21.9 20.9 21.8 21.9 20.8 MP% 58.6 58.7 58.1 58.5 58.6 58.3 Basic% 19.7 19.4 21.0 19.7 19.5 20.9 NR-CE MP% 96.6 96.6 96.0 96.5 96.8 96.2 LMW% 3.2 2.9 3.3 3.2 3.0 3.4 PS80% 0.04 0.05 0.05 0.04 0.05 0.05 (3) Accelerated (25±2°C / 60 ± 5% RH) experiment results Accelerated stability study was conducted to examine the changes in relevant quality attributes of the samples stored at 25±2°C and 60 + 5% RH, with the aim of preliminarily determining the stability of the samples under room temperature condition. The summary of the accelerated experiment results is shown in Table 16. As shown in Table 16, within 8 weeks of incubation at 25°C, no significant changes were observed in the protein concentration, appearance, and visible particles of both formulations, and they all met the standards. The protein radius of each formulation remained basically unchanged during the incubation. For SEC and NR CE results, no significant changes were observed compared to TO, and there was almost no observed difference between the two formulations. For CEX results, the MP of both formulations showed a slight decrease. After 6-8 weeks of incubation, the decrease in F14 was slightly faster compared to F15, but the MP differences between the two formulations were less than 1%. From the PS80 content detection results, it can be seen that the PS80 content remained basically unchanged in F15 which included EDTA- 2Na, while the PS80 content in F14 decreased to 0.02% after 8 weeks of incubation at 25°C. Table 16. Result Summary of Formulation Confirmation Study-25±2°C / 60±5 %RH Formulation TO i^BiBB iOit Bis®^ TO BB6®^ B^i®B Appearance cc cc cc cc cc CC CC CC cc cc Visible Particle Meet the standard Protein Cone. (mg / mL) 117.5 117.2 118.6 119.9 118.8 124.2 118.8 118.3 121.1 120.5 DLS Radius(nm) 2.4 2.5 2.5 2.6 2.5 2.4 2.5 2.5 2.6 2.6 PD% 27.5 28.5 24.3 28.9 21.6 25.3 27.8 28.6 26.0 25.5 SEC HMW% 1.2 1.4 1.6 1.7 1.7 1.2 1.4 1.5 1.5 1.5 MP% 98.6 98.4 98.1 97.1 97.0 98.6 98.3 98.2 97.4 97.3 LMW% 0.2 0.3 0.3 1.2 1.3 0.2 0.3 0.3 1.2 1.2 CEX Acid% 21.8 22.7 23.7 23.7 24.7 21.8 22.7 23.7 23.1 24.1 MP% 58.6 58.2 57.7 56.3 55.7 58.5 58.3 57.6 56.9 56.4 Basic% 19.7 19.1 18.6 20.0 19.6 19.7 19.1 18.7 19.9 19.5 NR-CE MP% 96.6 96.3 95.6 94.8 93.7 96.5 96.3 96.1 94.8 94.3 LMW% 3.2 3.4 3.5 4.1 5.1 3.2 3.4 3.5 4.3 5.0 PS80% 0.05 0.05 0.05 0.04 0.02 0.05 0.05 0.05 0.04 0.04 (4) Forced degradation (40±2°C / 75±5 % RH) experiment results Forced degradation (40±2°C / ) stability study was conducted to examine the changes in relevant quality attributes of the samples stored at 40±2°C and 75 + 5% RH, with the aim of preliminarily determining the stability of the samples under high temperature and high humidity condition. The summary of forced degradation experiment results is shown in Table 17. As shown in Table 17, within 8 weeks of incubation at 40°C, no significant changes were observed in the protein concentration, appearance, and visible particles of both formulations, and they all met the standards. The protein radius of each formulation remained basically unchanged during the incubation. For the SEC results, the HMW of both formulations exhibited a certain degree of increase, with F14 showing a slightly faster trend than F15. For the CEX results, the MP purity of both formulations experienced rapid degradation, although the difference between formulations was not significant. For the NR CE results, both formulations showed fast degradation of the MP and formation of fragments, and the trend of F14 was slightly faster compared to F15, with a difference of 2% between the two formulations at 8 weeks. For the detection results of PS80 content, after 2 weeks of incubation, PS80 in F14 experienced rapid degradation, reducing to 0.01%, while F15 remained essentially unchanged after 8 weeks of incubation at 40°C. Table 17. Result Summary of Formulation Confirmation Study-40±2°C / 75±5 %RH Formulation TO B^IOB^ B^iWB^ ■BB^ TO B(IBB^ HKB^ Appearance cc cc cc cc cc CC cc cc cc cc Visible Particle Meet the standard Protein Cone. (mg / mL) 117.5 115.3 117.9 116.3 116.0 124.2 116.5 119.1 117.6 118.1 DLS Radius(nm) 2.4 2.6 2.6 2.6 2.7 2.4 2.6 2.7 2.7 2.7 PD% 27.5 30.0 24.3 12.2 27.9 25.3 24.8 22.6 14.9 24.7 SEC HMW% 1.2 2.8 4.1 4.7 5.4 1.2 2.0 2.6 3.1 4.4 MP% 98.6 96.5 94.7 92.2 90.9 98.6 97.3 96.3 94.3 92.4 LMW% 0.2 0.7 1.2 3.2 3.7 0.2 0.7 1.1 2.6 3.1 CEX Acid% 21.8 39.9 54.1 64.1 70.8 21.8 38.9 51.8 62.1 70.3 MP% 58.6 43.8 31.1 21.3 15.9 58.5 45.3 33.9 24.2 17.4 Basic% 19.7 16.4 14.8 14.6 13.3 19.7 15.8 14.3 13.7 12.3 NR-CE MP% 96.6 91.8 88.3 82.1 77.9 96.5 93.2 91.0 84.3 81.1 LMW% 3.2 7.0 9.4 14.7 18.3 3.2 6.1 8.1 13.3 16.3 PS80% 0.05 0.01 0.01 0.01 0.00 0.05 0.05 0.05 0.04 0.04 3. Analysis and Discussion From the results, it can be found that the optimal formulation of lOmM acetic acid system with pH 5.3, 7% (w / v) sucrose, and 0.05% PS80 met the stability requirements of high-centration antibody liquid formulations suitable for clinical drug administration. Meanwhile, using the same buffer system and excipients, the inclusion of EDTA 2NA further improved the stability of the protein, and effectively prevented the degradation of PS80. It is suggested that adding 50pM EDTA 2NA to the optimal formulation results in a better stability performance. Example 4: Process Optimization Study 1. Study Design According to the Formulation Confirmation Study, adding EDTA-2Na can prevent the degradation of PS80. In this Example, the formulation of lOmM acetic acid system with pH 5.3, 7% (w / v) sucrose, and 0.05% PS80 was selected as the final formulation for process optimization study; and the addition of EDTA -2Na was investigated in downstream processing (DSP) development. As described in the Methods, the antibody was purified and then processed by UFDF. In this Process Optimization Study, UFDF was performed by tangential Flow Filtration (TFF) that requires multiple passes through a TFF system. . EDTA-2Na was added into a TFF pool during the TFF at the amount of 50pM (formulation F16) or 500pM (formulation F17). The residual amounts of EDTA -2Na after TFF were respectively 24.3pM and 566.9pM. Then, the DSs from the TFF were formulated into Formulations 16 and 17 in Table 18. Table 18. Study Design of Process Optimization Study Formulation Protein Cone. Buffer system Excipient condition Test Items F16 120 mg / mL lOmM Acetate, pH 5.3 7.0%(w / v) Sucrose, 0.05% PS80 TO 40°C:2 / 4 / 6 / 8W Visual inspection, PS80 F17 2. Study Results Forced degradation (40±2°C / 75±5 % RH) experiment results As shown in Table 19, no significant differences or changes were observed in the appearance of the two formulations after incubation at 40°C for 8 weeks. There was a small increase in visible particles in both formulations, with the highest increase at 6 weeks, and F17 has slightly more visible particles than F16. For the detection results of PS80 content, after incubation at 40°C for 8 weeks, the PS80 contents of both formulations decreased by 0.01%, thus no significant degradation occurred. Table 19. Results Summary of Process Optimization Study _40°C Formulation Appearance ^Visible Particle iiiiiioiiiiiiiii F16 TO CC Meet the standard 0.04 2W cc Bl*2 0.04 4W CC Bl*l 0.04 6W cc D1*1,D2*3, Bl*2 0.04 8W cc Dl*2 0.03 F17 TO cc Meet the standard 0.04 2W cc Bl*2, B2*l 0.04 4W cc Dl*2 0.04 6W cc Dl*3 DI, B2*l, D3, B2*l, Bl*2 0.04 8W cc No newly added 0.03 The shape of visible particles is described using the codes “D” for white-dot and “B” for fiber or lump. The number following the shape code represents the quantity of visible particles in a single vial, while the number following the “*” symbol indicates the total number of vials with visible particles. 3. Analysis and Discussion From the high-temperature experimental results mentioned above, it can be seen that 50pM or 500qM of EDTA-2Na added during TFF effectively protected PS80 from degradation, and the samples obtained using 50pM EDTA-2Na had fewer newly added visible particles after stress treatment. Therefore, it can be concluded that an addition amount of 50qM of EDTA-2Na would be suitable for DSP. Example 5: Process Confirmation Study 1. Study Design Based on the Process Optimization Study, adding 50qM EDTA-2Na during downstream process (DSP) of antibodies can prevent the degradation of PS80. In this Process Confirmation study, formulations F18, F19 and F20 in Table 20 were prepared to investigate the effects of adding 50qM of EDTA-2Na at different stages during the DSP. Briefly, the formulations Fl8 to F20 were prepared following a similar process as described in the Methods, with the exception of the following modification. Fl8 was prepared by using TFF pool to add EDTA-2Na during TFF, as described in Example 4. F19 was prepared by using VF pool (that is, the antibody pool obtained from virus filtration) to add EDTA-2Na, and then subjecting the VF pool to TFF to provide the DS. To prepare the F20, drug substance (DS) obtained by purification was subjected to a further protein A (PA) chromatography and then to a further TFF operation, during which a TFF pool including EDTA-2Na was used to provide a reprocessed DS. The residual amounts of EDTA-2Na after TFF were 64pM(F18), 5.5pM(F19), and 7.6pM (F20) for the three samples, respectively. The DSs and the reprocessed DS from the TFF were formulated into the formulations F18, F19 and F20 in Table 18. Table 20. Study Design of Process Confirmation Study Formulation Protein Cone. Buffer system Excipient condition Test Items F18 120mg / mL lOmM Acetate, pH 5.3 7.0%(w / v) Sucrose, 0.05% PS80 TO 5°C:2 / 4W 25°C:2 / 4W 40°C:2 / 4W Visual Inspection, PS80, SEC, CEX, NR CE F19 F20 2. Study Results (1) Long term (5±3°C) experiment results As shown Table 21, within 4 weeks of incubation at 5 °C, no significant changes were observed in the appearance and visible particles of the three formulations, and they all met the standards. For the results of SEC, CEX, NR CE, and PS80 Content, almost no differences were observed among the three formulations and no significant changes were observed compared to TO. (2) Accelerated (25±2°C / 60 ± 5% RH) experiment results As shown Table 22, within 4 weeks of incubation at 25°C, no significant changes were observed in the appearance and visible particles of the three formulations, and they all met the standards. For the results of SEC, CEX, NR CE, and PS80 Content, almost no differences were observed among the three formulations and no significant changes were observed compared to TO. (3) Forced degradation (40±2°C / 75±5 % RH) experiment results As shown Table 23, within 4 weeks of incubation at 40°C, no significant changes were observed in the appearance and visible particles of the three formulations, and they all met the standards. For the SEC results, at 4 weeks, there was an increase of about 2% in HMW compared to TO, and no difference was observed among the three formulations. For CEX results, compared to TO, the MP decreased rapidly, while the AP increased; and no differences were observed among the three formulations. For the NR CE-SDS results, at 4 weeks, there was an increase of about 6% in LMW compared to TO, and no difference was observed among the three formulations. Table 21. Results Summary of Process Confirmation Study _5°C Formulation BBBBBBBBBBBB8IBBBBBBBBBB Fl 9 IBBBBBBBBBSiBBBBBBBBBB^ TO BB®BB^ BB®iB( BBBiBB^ (BIIUBB^ TO BBiUBB^ BB^ilBB^ Appearance cc cc cc cc CC cc CC cc cc Visible Particle Meet the standard SEC HMW% 1.5 1.5 1.5 1.4 1.2 1.5 1.3 1.4 1.5 MP% 98.1 98.2 98.2 98.6 98.8 98.5 98.5 98.5 98.4 LMW% 0.3 0.3 0.3 ND ND 0.1 0.2 0.1 0.2 CEX Acid% 22.7 23.1 23.1 23.5 23.5 22.5 24.7 24.7 23.8 MP% 57.6 57.1 57.1 59.8 59.8 59.8 56.9 57.0 57.0 Basic% 19.7 19.7 19.8 16.7 16.7 17.7 18.4 18.4 19.3 NR- MP% 96.5 96.3 96.3 95.9 95.9 96.2 96.0 96.0 96.1 CE LMW% 3.2 3.4 3.4 3.2 3.3 3.0 3.4 3.3 3.3 PS80% 0.04 NT 0.05 0.04 NT NT 0.04 NT NT Table 22. Results Summary of Process Confirmation Study _25°C Formulation F19 IBBBBBBBBBSiBBBBBBBBBB^ iboobb^ TO TO BB^BBBB^ BB^ilBB^ Appearance cc cc cc CC cc cc CC cc cc Visible Particle Meet the standard SEC HMW% 1.5 1.6 1.7 1.4 1.7 1.9 1.3 1.7 2.0 MP% 98.1 98.0 97.9 98.6 98.2 98.0 98.5 98.1 97.8 LMW% 0.3 0.3 0.4 ND 0.1 0.2 0.2 0.2 0.2 CEX Acid% 22.7 23.9 24.8 23.5 24.2 24.1 24.7 25.4 25.4 MP% 57.6 56.8 56.1 59.8 59.3 58.7 56.9 56.6 56.1 Basic% 19.7 19.3 19.1 16.7 16.5 17.1 18.4 18.0 18.5 NR-CE MP% 96.5 95.9 95.9 95.9 95.6 95.7 96.0 95.6 95.7 LMW% 3.2 3.8 3.8 3.2 3.4 3.4 3.4 3.5 3.5 PS80% 0.04 NT 0.05 0.04 0.05 0.05 0.04 0.04 0.04 Table 23. Results Summary of Process Confirmation Study _40°C Formulation BBBBBBBBBBBIiBBBBBBBBOBB F19 IBBBBBBBBBSiBBBBBBBBBB^ TO TO Appearance cc CC cc CC CC cc CC cc CC Visible Particle Meet the standard SEC HMW% 1.5 2.3 3.4 1.4 2.5 3.2 1.3 2.7 3.5 MP% 98.1 96.9 95.1 98.6 96.9 95.7 98.5 96.6 95.4 LMW% 0.3 0.8 1.5 ND 0.6 1.1 0.2 0.7 1.1 CEX Acid% 22.7 42.1 56.6 23.5 42.0 53.4 24.7 42.5 54.0 MP% 57.6 41.7 29.0 59.8 43.9 32.5 56.9 42.6 31.5 Basic% 19.7 16.2 14.5 16.7 14.2 14.1 18.4 14.8 14.4 NR-CE MP% 96.5 93.0 89.2 95.9 92.4 89.6 96.0 92.6 89.6 LMW% 3.2 6.5 9.4 3.2 6.0 8.4 3.4 5.9 8.3 PS80% 0.04 NT 0.05 0.04 0.04 0.04 0.04 0.04 0.04 3. Analysis and Discussion The results proved that adding 50pM EDTA-2Na at different stages in the downstream process can prevent the degradation of PS80, and enhance the stability of the antibody protein. Sequence Listing SEQ ID NO: description sequence 1 Anti-Claudin 18.2 variable heavy chain (VH) QVQLVQSGAEVKKPGASVKVSCKASGYTFTGYNMNWVRQAPGQGLE WMGNIDPYYGGTSYNQKFKGRVTMTIDKSTSTVYMELSSLRSEDTAVY YCARMYHGNAFDYWGQGTTVTVSS 2 Anti-Claudin 18.2 variable light chain (VL) DIVMTQSPDSLAVSLGERATINCKSSQSLLNSGNLKNYLTWYQQKPGQP PKLLIYWASTRKSGVPDRFSGSGSGTDFTLTISSLQAEDVAVYYCQNDYS YPLTFGGGTKVEIK 3 Anti-Claudin 18.2 heavy chain (H) QVQLVQSGAEVKKPGASVKVSCKASGYTFTGYNMNWVRQAPGQGLE WMGNIDPYYGGTSYNQKFKGRVTMTIDKSTSTVYMELSSLRSEDTAVY YCARMYHGNAFDYWGQGTTVTVSS ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSG VHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKV EPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVWD VSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRWSVLTVLHQD WLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKN QVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLT VDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 4 Anti-Claudin 18.2 light chain (L) DIVMTQSPDSLAVSLGERATINCKSSQSLLNSGNLKNYLTWYQQKPGQP PKLLIYWASTRKSGVPDRFSGSGSGTDFTLTISSLQAEDVAVYYCQNDYS YPLTFGGGTKVEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPRE AKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHK VYACEVTHQGLS SPVTKSFNRGEC 5 Anti-Claudin 18.2 HCDR1 GYNMN 6 Anti-Claudin 18.2 HCDR2 NIDPYYGGTSYNQKFKG 7 Anti-Claudin 18.2 HCDR3 MYHGNAFDY 8 Anti-Claudin 18.2 LCDR1 KSSQSLLNSGNLKNYLT 9 Anti-Claudin 18.2 LCDR2 WASTRKS 10 Anti-Claudin 18.2 LCDR3 QNDYSYPLT 11 Human     IgGl constant region (CH) ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSG VHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKV EPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVWD VSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRWSVLTVLHQD WLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKN QVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLT VDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 12 Human     Light constant region Kappa (CLk) RTVAAPSVFIFPPSDEQLKSGTASWCLLNNFYPREAKVQWKVDNALQS GNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPV TKSFNRGEC 13 Human IgGl Fc region (Fc) EPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVWD VSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRWSVLTVLHQD WLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKN QVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLT VDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK

Claims

1. A liquid antibody formulation, comprising:(i) an anti-Claudinl8.2 antibody protein;(ii) a buffer, wherein the buffer is an acetate buffer or a histidine buffer;(iii) a stabilizer, wherein the stabilizer is sucrose; and(iv) a surfactant, wherein the surfactant is a polysorbate or a poloxamer,wherein the pH of the liquid antibody formulation is about 5.0 to about 6.0, preferably about 5.1 to about 5.5, more preferably about 5.3;wherein the anti-Claudinl 8.2 antibody protein comprises a VH region and a VL region, wherein the VH region comprises the heavy chain CDRs (HCDR1, HCDR2, HCDR3) contained in the heavy variable region as shown in SEQ ID NO: 1; and wherein the VL region comprises the light chain CDRs (LCDR1, LCDR2, LCDR3) contained in the light variable region as shown in SEQ ID NO: 2,optionally, the HCDR1, the HCDR2, the HCDR3, the LCDR1, the LCDR2 and the LCDR3 comprises the sequences as shown in SEQ ID NOs: 5-10, respectively.

2. The liquid antibody formulation according to claim 1, wherein the concentration of the anti-Claudinl8.2 antibody protein in the liquid antibody formulation is about 50 mg / mL to about 150 mg / mL, about 100 mg / mL to about 150mg / mL, or about HOmg / mL to about 130mg / ml, e.g., about 100 mg / mL, about 110 mg / mL, about 120 mg / mL, or about 130 mg / m.

3. The liquid antibody formulation according to any one of claim 1 to 2, wherein:- the surfactant is selected from the group consisting of polysorbate-80, polysorbate-20, polysorbate-60, polysorbate-40, and poloxamer 188; or- the surfactant is polysorbate-80.

4. The liquid antibody formulation according to any one of claim 1 to 3, wherein:- the buffer is an acetate buffer or a histidine buffer;- the stabilizer is sucrose; and- the surfactant is polysorbate-80.

5. The liquid antibody formulation according to any one of claim 1 to 4, wherein:- the buffer is an acetate buffer comprising acetic acid, sodium acetate or combination thereof; or- the buffer is a histidine buffer comprising histidine, histidine hydrochloride or combination thereof.

6. The liquid antibody formulation according to any one of claim 1 to 5, wherein:- the buffer is about 5mM to about 50mM, optionally wherein the buffer is about 5mM to about 20mM acetate buffer; or the buffer is about 5 to about 20mM histidine buffer;- the stabilizer is about 100 to about 500 mM, optionally about 150 to about 350 mM, e.g., about 150 mM, about 180 mM, about 200 mM, about 220 mM, about 250 mM, about 300 mM, or about 350 mM; and / or- the surfactant is about 0.1 mg / mL to about 1 mg / mL, optionally about 0.2 mg / mL to about 0.8 mg / mL, e.g., about 0.2 mg / mL, about 0.3 mg / mL, about 0.4 mg / mL, about 0.5 mg / mL, about 0.6 mg / mL, about 0.7 mg / mL or about 0.8 mg / mL.

7. The liquid antibody formulation according to any one of claim 1 to 6, wherein the formulation further comprises a chelating agent, optionally wherein:- the chelating agent is selected from the group consisting of EDTA, DTPA and combination thereof, and / or- the concentration of the chelating agent is about lOpM to about lOOqM, optionally about 20pM to about 70pM. e.g., about 20pM. about 30qM, about 40pM. about 50qM, about 60pM. or about 70pM.

8. The liquid antibody formulation according to any one of claim 1 to 7, wherein:- the anti-Claudin 18.2 antibody protein comprises a VH region comprising SEQ ID NO: 1 or a sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or higher identity thereto, and a VL region comprising SEQ ID NO: 2 or a sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or higher identity thereto;- the anti-Claudin 18.2 antibody protein comprises a VH region comprising SEQ ID NO: 1 and a VL region comprising SEQ ID NO: 2;- the anti-Claudin 18.2 antibody protein comprises a heavy chain comprising SEQ ID NO: 3 or a sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or higher identity thereto, and a light chain comprising SEQ ID NO: 4 or a sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or higher identity thereto; or- the anti-Claudin 18.2 antibody protein comprises a heavy chain comprising SEQ ID NO: 3 and a light chain comprising SEQ ID NO: 4.

9. The liquid antibody formulation according to any one of claims 1 to 8, wherein the anti-Claudin 18.2 antibody protein is recombinantly expressed in HEK293 cells or in CHO cells.

10. The liquid antibody formulation according to any one of claims 1 to 9, wherein the liquid formulation is an injection, optionally for subcutaneous, intravenous or intramuscular injection, or an infusion, optionally for intravenous infusion.

11. The liquid antibody formulation according to any one of claims 1 to 10, wherein the liquid antibody formulation comprises:(i) about lOOmg / ml to about 150 mg / mL of the anti-Claudinl8.2 antibody protein;(ii) about 5mM to about 20 mM of an acetate buffer or about 5mM to about 20mM of a histidine buffer;(iii) about 50mg / ml to about 100 mg / mL of sucrose;(iv) about 0.2mg / ml to about 0.8 mg / mL of polysorbate 80; andoptionally, (v) about 20qM to about 70qM of EDTA;wherein the pH of the liquid formulation is about 5.1 to about 5.5, preferably about 5.3;preferably,wherein the liquid antibody formulation comprises:(i) about 110 to about 130 mg / mL of the anti-Claudinl8.2 antibody protein,(ii) about 10 mM of an acetate buffer or about 10 mM of a histidine buffer,(iii) about 60mg / ml to about 80 mg / mL of sucrose,(iv) about 0.3mg / ml to about 0.6 mg / mL of polysorbate 80,wherein the pH of the liquid formulation is about 5.1 to about 5.5, preferably about 5.3;orwherein the liquid antibody formulation comprises:(i) about 110 to about 130 mg / mL of the anti-Claudinl8.2 antibody protein,(ii) about 10 mM of an acetate buffer or about 10 mM of a histidine buffer,(iii) about 60mg / ml to about 80 mg / mL of sucrose,(iv) about 0.3mg / ml to about 0.6 mg / mL of polysorbate 80, and(v) about 40qM to about 60 qM of EDTA;wherein the pH of the liquid formulation is about 5.1 to about 5.5, preferably about 5.3;orwherein the liquid antibody formulation comprises:(i) about 120 mg / mL of the anti-Claudinl8.2 antibody protein;(ii) about lOmM of an acetate buffer consisting of acetic acid and sodium acetate;(iii) about 70 mg / mL of sucrose; and(iv) about 0.5 mg / mL of polysorbate 80;wherein the pH of the liquid formulation is about 5.1 to about 5.5, preferably about 5.3;orwherein the liquid antibody formulation comprises:(i) about 120 mg / mL of the anti-Claudinl8.2 antibody protein;(ii) about lOmM of an acetate buffer consisting of acetic acid and sodium acetate;(iii) about 70 mg / mL of sucrose; and(iv) about 0.5 mg / mL of polysorbate 80; and(v) about 50pM of EDTA,wherein the pH of the liquid formulation is about 5.1 to about 5.5, preferably about 5.3;orwherein the liquid antibody formulation comprises:(i) about 120 mg / mL of the anti-Claudinl8.2 antibody protein;(ii) about lOmM of a histidine buffer consisting of histidine and histidine hydrochloride;(iii) about 70 mg / mL of sucrose; and(iv) about 0.5 mg / mL of polysorbate 80;wherein the pH of the liquid formulation is about 5.1 to about 5.5, preferably about 5.3;orwherein the liquid antibody formulation comprises:(i) about 120 mg / mL of the anti-Claudinl8.2 antibody protein;(ii) about lOmM of a histidine buffer consisting of histidine and histidine hydrochloride;(iii) about 70 mg / mL of sucrose; and(iv) about 0.5 mg / mL of polysorbate 80; and(v) about 50pM of EDTA,wherein the pH of the liquid formulation is about 5.1 to about 5.5, preferably about 5.3.

12. The liquid antibody formulation according to any one of claims 1 to 11, wherein after storage, e.g., at 28 °C for at least 24 months, at room temperature for at least 2 months, or at 40±2 °C for at least 1 month, the formulation is stable and preferably has one or more of the following characteristics:(i) a purity of the anti-Claudin 18.2 antibody protein greater than 90%, 95%, 96%, 97%, 98% or 99%, as measured by SEC-HPLC;(ii) a purity of the anti-Claudinl8.2 antibody protein greater than 80%, 85%, 90%, 92%, 94%, 96% or 98%, as measured by non-reduced CE-SDS;(iii) the change in the main species and / or the charge variants of the antibody protein less than 50%, 40%, 30%, 20%, 10% or 5%, relative to an initial value, as measured by cation exchange chromatography; and(iv) the decrease in the activity of the anti-Claudinl8.2 antibody protein less than 50%, 40%, 30%, 20%, 10% or 5%, relative to an initial value, as measured by a cell-based potency assay, andoptionally, (v) the change in the amount of the surfactant (especially, polysorbate 80) less than 0.01% or 0.02%, relative to an initial value.

13. The liquid antibody formulation according to any one of claims 1 to 12, which is a pre-filled syringe dosage form for subcutaneous injection.

14. A solid antibody formulation obtained by solidifying the liquid antibody formulation according to any one of claims 1 to 13, optionally wherein the solid formulation is a lyophilized powder for injection.

15. A delivery device, comprising the liquid antibody formulation according to any one of claims 1 to 13 or the solid antibody formulation according to claim 14, optionally wherein the device is a pre-filled syringe for use in injection, optionally subcutaneous, intravenous or intramuscular injection.

16. Use of the liquid antibody formulation according to any one of claims 1 to 13 or the solid antibody formulation according to claim 14 in preparing a medicament for treating or preventing a cancer, such as a digestive cancer, e.g., gastric cancer (GC), gastroesophageal junction (GEJ) cancer, esophageal cancer, or pancreatic cancer.

17. A method for preparing the liquid antibody formulation according to any one of claims 1 to 13, which include the steps of:(a) producing a drug substance (DS) from a mixture comprising the antibody by a downstream process (DSP), and(b) formulating the drug substance into the formulation.

18. The method according to claim 17, wherein a chelating agent is added into a processing solution of the DSP at step (a),preferably, the DSP includes at least one of a chromatography process, a virus filtration (VF) process and a ultrafiltration and diafiltration (UFDF) process, and the chelating agent is added into the processing solution selected from the group consisting of chromatography pool, the VF pool and the UFDF pool,optionally, the processing solution with the addition of EDTA is used for a UFDF process to provide the DS,optionally, the UFDF process is performed by Tangential Flow Filtration (TFF),optionally, the chelating agent is selected from the group consisting of EDTA, DTPA and combination thereof, or the chelating agent is EDTA.

19. The method according to claims 18, wherein the chelating agent is added in a stabilizing effective amount, or in an amount of about 30pM to about I OOpM. or in amount of about 50pM.

20. The method according to claim 18 or claim 19, wherein the residue amount of the chelating agent in the DS is about IpM to about lOOpM, preferably less than 50pM, more preferably less than 20pM or lOpM.