Pharmaceutical composition for treating cancer comprising fusion protein comprising CD80 protein and il-2 protein and antibody-drug conjugate

Abstract

The present invention relates to a composition for preventing or treating cancer, the composition comprising, as active ingredients: a fusion protein comprising a CD80 protein and an IL-2 protein; and an anti-HER2 antibody-drug conjugate. The present invention achieves a synergistic anticancer effect by conjugating trastuzumab, which has a low initial therapeutic response and a high proportion of resistant patients, with exatecan, which is a topoisomerase I inhibitor, and then administering the conjugate in combination with a fusion protein comprising a CD80 protein and an IL-2 protein. Therefore, the present invention can maximize the efficiency of trastuzumab as a therapeutic antibody, thereby ultimately achieving significant improvement in patient survival rates.

Description

Pharmaceutical composition for treating cancer comprising a fusion protein and an antibody-drug conjugate comprising CD80 protein and IL-2 protein

[0001] The present invention relates to a pharmaceutical composition for treating cancer, comprising a fusion protein comprising CD80 protein and IL-2 protein and an antibody-drug conjugate, specifically a conjugate of an anti-HER2 antibody and a topoisomerase I inhibitor.

[0002]

[0003] IL-2 (Interleukin-2) is a cytokine produced by activated T cells. It stimulates the proliferation and differentiation of T cells, and plays a key role in the production, survival, and homeostasis of lymphocytes by inducing the production of cytotoxic T lymphocytes and the differentiation of peripheral blood lymphocytes into cytotoxic cells and lymphokine-activated killer cells. In addition, CD80 (Cluster of Differentiation 80) is a co-stimulatory molecule expressed on the surface of antigen-presenting cells such as dendritic cells, macrophages, and B cells, and is one of the B7 family proteins that provides co-stimulatory signals essential for the activation and survival of T cells. CD80 binds to CD28, CTLA-4 (CD152), and PD-L1 (programmed cell death ligand 1) and is involved in the activation, proliferation, differentiation, and survival of T cells. Thus, both IL-2 and CD80 contribute to regulating immune responses and amplifying the body's immune response against cancer cells.

[0004] Meanwhile, tumor treatment methods have evolved over the past several decades through various approaches, and in particular, the development of immune checkpoint inhibitors and antibody-drug conjugates (ADCs) has dramatically improved the efficacy of targeted therapy against tumors. ENHERTU ®It is an ADC targeting HER2 (human epidermal growth factor receptor 2) positive cancer, and is in the form of a conjugate of Trastuzumab and a topoisomerase Ⅰ inhibitor, and is currently being clinically proven to be effective against various solid cancers.

[0005] However, single agents have limitations in overcoming the immunosuppressive nature of the tumor microenvironment, and therapeutic efficacy may be limited by cancer cell heterogeneity and immune evasion mechanisms. Therefore, there is a growing need for novel anticancer treatment strategies that induce synergistic effects by combining or fusing antibody-drug conjugates, which directly kill tumor cells, with immunomodulatory proteins, which activate immune cells.

[0006]

[0007] Numerous papers and patents are referenced and cited throughout this specification. The disclosures of these cited papers and patents are incorporated herein by reference in their entirety to provide a clearer understanding of the state of the art and the scope of the present invention.

[0008]

[0009] The present inventors have devoted extensive research efforts to develop an efficient combination therapy method that can significantly enhance the therapeutic activity of anticancer antibodies. As a result, the present inventors have completed the present invention by demonstrating that the therapeutic efficacy of HER2-positive tumors is dramatically improved when an antibody-drug conjugate comprising an anti-HER2 antibody, particularly trastuzumab, which has a low initial therapeutic response and a high proportion of resistant patients, is conjugated to a topoisomerase I inhibitor and a fusion protein comprising CD80 and IL-2 proteins.

[0010] Accordingly, the purpose of the present invention is to provide a composition for preventing or treating cancer, which comprises a fusion protein comprising a CD80 protein and an IL-2 protein; and an anti-HER2 antibody-drug conjugate as active ingredients.

[0011] Other objects and advantages of the present invention will become more apparent from the detailed description, claims and drawings below.

[0012]

[0013] According to one aspect of the present invention, the present invention provides a composition for preventing or treating cancer, comprising a fusion protein comprising a CD80 protein or a fragment thereof and an IL-2 protein or a variant thereof; and a conjugate of an anti-HER2 antibody or an antigen-binding fragment thereof and a low-molecular-weight anticancer agent as active ingredients.

[0014] According to another aspect of the present invention, there is provided a method for preventing or treating cancer, comprising administering to a subject a fusion protein comprising a CD80 protein or a fragment thereof and an IL-2 protein or a variant thereof; and a conjugate of an anti-HER2 antibody or an antigen-binding fragment thereof and a small molecule anticancer agent.

[0015] The present inventors have devoted extensive research efforts to develop an effective combination therapy that can significantly improve the therapeutic response of anti-HER2 antibodies, particularly trastuzumab, which has a low initial therapeutic response and a high rate of innate and acquired resistance in up to 50% of patients. As a result, we discovered that co-administration of an antibody-drug conjugate comprising a trastuzumab-topoisomerase I inhibitor and a fusion protein comprising CD80 and IL-2 proteins resulted in a significant synergistic effect on the mortality rate and survival rate of HER2-positive tumors, including breast cancer.

[0016] As used herein, the term “fusion protein” refers to a recombinant protein molecule in which an amino acid sequence derived from a specific protein or domain is fused with another amino acid sequence derived from a different protein or domain. The amino acid sequences of different origins may be directly linked within the fusion protein, or may be linked via a linker sequence, a tag sequence, a self-cleaving sequence, or a combination thereof.

[0017] As used herein, the term "IL-2 (Interleukin-2)" refers to wild-type IL-2 obtained from any vertebrate source, including primates and rodents. IL-2 may be obtained from animal cells, but also includes those obtained from recombinant cells capable of producing IL-2. The IL-2 may be in a mature form. Specifically, the mature IL-2 may not include a signal sequence and may have the amino acid sequence of SEQ ID NO: 7. In this case, the IL-2 may include a fragment in which a portion of the N-terminus or C-terminus of the wild-type IL-2 is deleted (truncated).

[0018] As used herein, the term "IL-2 variant" refers to a form in which a portion of an amino acid is substituted in full-length IL-2 or a fragment of the IL-2 described above. The IL-2 variant may have activity equivalent to or similar to wild-type IL-2. Here, "IL-2 activity" may refer to, for example, the ability to specifically bind to an IL-2 receptor, and the specific binding can be measured using a method known to those skilled in the art.

[0019] Specifically, the IL-2 variant may be a variant in which some of the amino acids of the wild-type IL-2 are substituted, and includes a substitution of one or more amino acids among the 38th, 42nd, 45th, 61st, and 72nd amino acids in the amino acid sequence of SEQ ID NO: 7.

[0020] In one specific example, the IL-2 variant may be a variant in which amino acid substitutions occur at two residue positions. Specifically, the IL-2 variant may be one in which the 38th and 42nd amino acids in the amino acid sequence of SEQ ID NO: 7 are substituted. Furthermore, in one specific example, the IL-2 variant may be one in which the 38th and 61st amino acids in the amino acid sequence of SEQ ID NO: 7 are substituted. Furthermore, in one specific example, the IL-2 variant may be one in which the 38th and 72nd amino acids in the amino acid sequence of SEQ ID NO: 7 are substituted. Furthermore, in one specific example, the IL-2 variant may be one in which the 42nd and 45th amino acids in the amino acid sequence of SEQ ID NO: 7 are substituted. Furthermore, in one specific example, the IL-2 variant may be one in which the 42nd and 61st amino acids in the amino acid sequence of SEQ ID NO: 7 are substituted. In addition, as a specific example, the IL-2 variant may be one in which the 42nd and 72nd amino acids are substituted in the amino acid sequence of SEQ ID NO: 7. In addition, as a specific example, the IL-2 variant may be one in which the 45th and 61st amino acids are substituted in the amino acid sequence of SEQ ID NO: 7. In addition, as a specific example, the IL-2 variant may be one in which the 45th and 72nd amino acids are substituted in the amino acid sequence of SEQ ID NO: 7. In addition, as a specific example, the IL-2 variant may be one in which the 61st and 72nd amino acids are substituted in the amino acid sequence of SEQ ID NO: 7.

[0021] Furthermore, the IL-2 variant may be a variant in which amino acid substitutions occur at three residue positions. Specifically, the IL-2 variant may be one in which the 38th, 42nd, and 45th amino acids in the amino acid sequence of SEQ ID NO: 7 are substituted. In addition, as a specific example, the IL-2 variant may be one in which the 38th, 42nd, and 61st amino acids in the amino acid sequence of SEQ ID NO: 7 are substituted. In addition, as a specific example, the IL-2 variant may be one in which the 38th, 42nd, and 72nd amino acids in the amino acid sequence of SEQ ID NO: 7 are substituted. In addition, as a specific example, the IL-2 variant may be one in which the 38th, 45th, and 61st amino acids in the amino acid sequence of SEQ ID NO: 7 are substituted. In addition, as a specific example, the IL-2 variant may be one in which the 38th, 45th, and 72nd amino acids in the amino acid sequence of SEQ ID NO: 7 are substituted. In addition, as a specific example, the IL-2 variant may be one in which the 38th, 61st, and 72nd amino acids in the amino acid sequence of SEQ ID NO: 7 are substituted. In addition, as a specific example, the IL-2 variant may be one in which the 42nd, 45th, and 61st amino acids in the amino acid sequence of SEQ ID NO: 7 are substituted. In addition, as a specific example, the IL-2 variant may be one in which the 42nd, 45th, and 72nd amino acids in the amino acid sequence of SEQ ID NO: 7 are substituted. In addition, as a specific example, the IL-2 variant may be one in which the 45th, 61st, and 72nd amino acids in the amino acid sequence of SEQ ID NO: 7 are substituted.

[0022] At this time, the "other amino acid" introduced by the residue position listed above may be any one selected from the group consisting of alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine. However, in the amino acid substitution of the IL-2 variant, the 38th position in the amino acid sequence of SEQ ID NO: 7 cannot be substituted with arginine, the 42nd position cannot be substituted with phenylalanine, the 45th position cannot be substituted with tyrosine, the 61st position cannot be substituted with glutamic acid, and the 72nd position cannot be substituted with leucine.

[0023] In the amino acid substitution of the IL-2 variant, arginine, which is the 38th amino acid in the amino acid sequence of SEQ ID NO: 7, may be substituted with an amino acid other than arginine. Preferably, in the amino acid substitution of the IL-2 variant, arginine, which is the 38th amino acid in the amino acid sequence of SEQ ID NO: 7, may be substituted with alanine (R38A).

[0024] In the amino acid substitution of the IL-2 variant, phenylalanine, which is the 42nd amino acid in the amino acid sequence of SEQ ID NO: 7, may be substituted with an amino acid other than phenylalanine. Preferably, in the amino acid substitution of the IL-2 variant, phenylalanine, which is the 42nd amino acid in the amino acid sequence of SEQ ID NO: 7, may be substituted with alanine (F42A).

[0025] In the amino acid substitution of the IL-2 variant, tyrosine, which is the 45th amino acid in the amino acid sequence of SEQ ID NO: 7, may be substituted with an amino acid other than tyrosine. Preferably, in the amino acid substitution of the IL-2 variant, tyrosine, which is the 45th amino acid in the amino acid sequence of SEQ ID NO: 7, may be substituted with alanine (Y45A).

[0026] In the amino acid substitution of the IL-2 variant, glutamic acid, which is the 61st amino acid in the amino acid sequence of SEQ ID NO: 7, may be substituted with an amino acid other than glutamic acid. Preferably, in the amino acid substitution of the IL-2 variant, glutamic acid, which is the 61st amino acid in the amino acid sequence of SEQ ID NO: 7, may be substituted with arginine (E61R).

[0027] In the amino acid substitution of the IL-2 variant, leucine, which is the 72nd amino acid in the amino acid sequence of SEQ ID NO: 7, may be substituted with an amino acid other than leucine. Preferably, in the amino acid substitution of the IL-2 variant, leucine, which is the 72nd amino acid in the amino acid sequence of SEQ ID NO: 7, may be substituted with glycine (L72G).

[0028] Specifically, the IL-2 variant may have at least one substitution selected from the group consisting of R38A, F42A, Y45A, E61R, and L72G in the amino acid sequence of SEQ ID NO: 7.

[0029] Specifically, the IL-2 variant may have two or three substitutions selected from the group consisting of R38A, F42A, Y45A, E61R and L72G.

[0030] In addition, the IL-2 variant may be a form in which two amino acids are substituted. Specifically, the IL-2 variant may be a form in which R38A and F42A are substituted. In addition, in one specific example, the IL-2 variant may be a form in which R38A and Y45A are substituted. In addition, in one specific example, the IL-2 variant may be a form in which R38A and E61R are substituted. In addition, in one specific example, the IL-2 variant may be a form in which R38A and L72G are substituted. In addition, in one specific example, the IL-2 variant may be a form in which F42A and Y45A are substituted. In addition, in one specific example, the IL-2 variant may be a form in which F42A and E61R are substituted. In addition, in one specific example, the IL-2 variant may be a form in which F42A and L72G are substituted. Additionally, as a specific example, the IL-2 variant may have substitutions of E61R and L72G.

[0031] Furthermore, the IL-2 variant may be a form in which three amino acids are substituted. Specifically, the IL-2 variant may be a form in which R38A, F42A, and Y45A are substituted. In addition, as a specific example, the IL-2 variant may be a form in which R38A, F42A, and E61R are substituted. In addition, as a specific example, the IL-2 variant may be a form in which R38A, F42A, and L72G are substituted. In addition, as a specific example, the IL-2 variant may be a form in which R38A, Y45A, and E61R are substituted. In addition, as a specific example, the IL-2 variant may be a form in which R38A, Y45A, and L72G are substituted. In addition, as a specific example, the IL-2 variant may be a form in which F42A, Y45A, and E61R are substituted. In addition, as a specific example, the IL-2 variant may be one in which substitutions occur at F42A, Y45A, and L72G. In addition, as a specific example, the IL-2 variant may be one in which substitutions occur at F42A, E61R, and L72G. In addition, as a specific example, the IL-2 variant may be one in which substitutions occur at Y45A, E61R, and L72G.

[0032] In addition, the IL-2 variant may be a form in which four amino acids are substituted. Specifically, the IL-2 variant may be a form in which substitutions occur at R38A, F42A, Y45A, and E61R. In addition, as a specific example, the IL-2 variant may be a form in which substitutions occur at R38A, F42A, Y45A, and L72G. In addition, as a specific example, the IL-2 variant may be a form in which substitutions occur at R38A, F42A, E61R, and L72G. In addition, as a specific example, the IL-2 variant may be a form in which substitutions occur at R38A, Y45A, E61R, and L72G. In addition, as a specific example, the IL-2 variant may be a form in which substitutions occur at F42A, Y45A, E61R, and L72G.

[0033] Furthermore, the IL-2 variant may have substitutions such as R38A, F42A, Y45A, E61R, and L72G.

[0034] Specifically, the IL-2 variant may have one or more substitutions selected from the group consisting of R38A, F42A, and E61R in the amino acid sequence of SEQ ID NO: 7. More specifically, the IL-2 variant may have one or more substitutions selected from the group consisting of R38A, F42A, and E61R in the amino acid sequence of SEQ ID NO: 7.

[0035] The IL-2 variant described above used in the present invention has reduced in vivo toxicity caused by binding to the alpha form of the IL-2 receptor (IL-2Rα) compared to wild-type IL-2.

[0036] In this specification, "CD80," also referred to as "B7-1," is a membrane protein present on dendritic cells, activated B cells, and monocytes that provides costimulatory signals essential for T cell activation and survival. CD80 consists of 288 amino acids and is known to be a ligand for two different proteins present on the surface of T cells: CD28 and CTLA-4.

[0037] As used herein, the term "CD80 fragment" refers to a fragment of the full-length CD80 protein in which some amino acid residues have been deleted, and thus is an analog of the full-length protein that retains its original biological activity and function. Specifically, it refers to a minimal fragment of CD80 capable of transmitting a costimulatory signal for T cell activation. For example, the functional fragment of CD80 may be the extracellular domain of CD80 or a fragment of the full-length CD80 protein comprising the same.

[0038] A specific example of a fragment of CD80 may be one in which all or part of the 1st to 34th amino acids from the N-terminus, which is the signal sequence of CD80, are removed. In addition, a specific example of the CD80 fragment may be a protein consisting of the 35th to 242nd amino acids of SEQ ID NO: 2. In addition, a specific example of the CD80 fragment may be a protein consisting of the 35th to 232nd amino acids of SEQ ID NO: 2. In addition, a specific example of the CD80 fragment may be a protein consisting of the 35th to 139th amino acids of SEQ ID NO: 2. In addition, a specific example of the CD80 fragment may be a protein consisting of the 142nd to 242nd amino acids of SEQ ID NO: 2.

[0039] More specifically, the fragment of the CD80 protein may be an extracellular domain of the CD80 protein. More specifically, the CD80 fragment may have the amino acid sequence of SEQ ID NO: 3.

[0040]

[0041] The term “antibody” as used herein means an antibody against the HER2 protein, which specifically recognizes and binds to a specific epitope of the protein, and includes not only a complete full-length antibody form but also an antigen-binding fragment (antibody fragment) of the antibody molecule.

[0042] A complete antibody has two full-length light chains and two full-length heavy chains, each light chain linked to a heavy chain by a disulfide bond. The heavy chain constant regions are of the gamma (γ), mu (μ), alpha (α), delta (δ), and epsilon (ε) types, and are subclassed into gamma1 (γ1), gamma2 (γ2), gamma3 (γ3), gamma4 (γ4), alpha1 (α1), and alpha2 (α2). The light chain constant regions are of the kappa (κ) and lambda (λ) types.

[0043] The term “antigen-binding fragment of an antibody” as used herein means a fragment possessing antigen-antibody binding function within the entire antibody molecule, and specifically includes a Fab fragment, an F(ab') fragment, an F(ab')2 fragment, and an Fv fragment.

[0044] Among antibody fragments, Fab has a structure with the variable regions of the light and heavy chains, the constant region of the light chain, and the first constant region (CH1) of the heavy chain, and has one antigen-binding site. Fab' differs from Fab in that it has a hinge region containing one or more cysteine ​​residues at the C-terminus of the CH1 domain of the heavy chain. F(ab')2 antibodies are produced when the cysteine ​​residues in the hinge region of Fab' form a disulfide bond. Fv is the smallest antibody fragment that has only the heavy chain variable region and the light chain variable region. The two-chain Fv (two-chain Fv) has the heavy chain variable region and the light chain variable region linked non-covalently, and the single-chain Fv (single-chain Fv, scFv) has the heavy chain variable region and the single chain variable region linked covalently through a peptide linker or directly at the C-terminus, so it can form a dimer-like structure like the two-chain Fv. These antibody fragments can be obtained using proteolytic enzymes (for example, restriction digestion of whole antibodies with papain yields Fab fragments, and digestion with pepsin yields F(ab')2 fragments), or they can be produced using genetic recombination techniques.

[0045] In the present invention, the term "specifically binds" means that an antibody or an antigen-binding fragment thereof forms a relatively stable complex with an antigen under physiological conditions. Specific binding is about 1 x 10 6 It can be characterized by an equilibrium dissociation constant (KD) of less than M. Methods for determining whether two molecules bind specifically are well known in the art, such as equilibrium dialysis and surface plasmon resonance.

[0046] As used herein, the term “affinity” refers to the combined strength of all non-covalent interactions between a single binding site of a molecule (e.g., an antibody) and its binding partner (e.g., an antigen). Unless otherwise specified, “binding affinity” refers to the intrinsic binding affinity reflecting a 1:1 interaction between members of a binding pair (e.g., an antibody and an antigen). The affinity of a molecule X for its partner Y can generally be expressed as a dissociation constant (KD). Affinity can be measured by conventional methods known in the art, including the methods described herein.

[0047] According to a specific embodiment of the present invention, the anti-HER2 antibody or antigen-binding fragment thereof comprises a heavy chain variable region comprising an HCDR1 region having an amino acid sequence of SEQ ID NO: 12; an HCDR2 region having an amino acid sequence of SEQ ID NO: 13; and an HCDR3 region having an amino acid sequence of SEQ ID NO: 14.

[0048] The term “heavy chain” as used herein refers to a full-length heavy chain and fragments thereof comprising a variable region domain VH comprising an amino acid sequence having sufficient variable region sequence to confer specificity for an antigen and three constant region domains CH1, CH2 and CH3.

[0049] As used herein, the term “CDR (complementarity determining region)” refers to the amino acid sequence of the hypervariable region of the immunoglobulin heavy and light chains. The heavy chain (HCDR1, HCDR2, and HCDR3) and the light chain (LCDR1, LCDR2, and LCDR3) each contain three CDRs, which provide key contact residues for antibody binding to an antigen or epitope.

[0050] The scope of the antibodies or antigen-binding fragments of the present invention includes variants having conservative amino acid substitutions in the CDR regions. In addition, the antibodies or antigen-binding fragments of the present invention may include variants of the amino acid sequences set forth in the attached sequence listing, as long as they can specifically recognize the HER2 protein. For example, additional changes may be made to the amino acid sequence of the antibody to further improve the binding affinity and / or other biological properties of the antibody. Such modifications include, for example, deletions, insertions, and / or substitutions of amino acid sequence residues of the antibody, and are made based on the relative similarity of the amino acid side chain substituents, such as hydrophobicity, hydrophilicity, charge, size, etc. Analysis of the size, shape, and type of amino acid side chain substituents reveals that arginine, lysine, and histidine are all positively charged residues; alanine, glycine, and serine have similar sizes; and phenylalanine, tryptophan, and tyrosine have similar shapes. Based on these considerations, arginine, lysine, and histidine; Alanine, glycine and serine; and phenylalanine, tryptophan and tyrosine can be considered biologically functional equivalents.

[0051] Furthermore, amino acid substitutions in proteins that do not alter the overall activity of the molecule are well known in the art (H. Neurath et al., The Proteins, Academic Press, New York, 1979). The most common exchanges are between amino acid residues Ala / Ser, Val / Ile, Asp / Glu, Thr / Ser, Ala / Gly, Ala / Thr, Ser / Asn, Ala / Val, Ser / Gly, Thr / Phe, Ala / Pro, Lys / Arg, Asp / Asn, Leu / Ile, Leu / Val, Ala / Glu, and Asp / Gly.

[0052] More specifically, the heavy chain variable region comprises the amino acid sequence of SEQ ID NO: 15.

[0053] According to a more specific embodiment of the present invention, the anti-HER2 antibody or antigen-binding fragment thereof additionally comprises a light chain variable region comprising an LCDR1 region having an amino acid sequence of SEQ ID NO: 16; an LCDR2 region having an amino acid sequence of SEQ ID NO: 17; and an LCDR3 region having an amino acid sequence of SEQ ID NO: 18.

[0054] The term “light chain” as used herein refers to both full-length light chains and fragments thereof comprising a variable region domain VL and a constant region domain CL, which comprise an amino acid sequence having sufficient variable region sequence to confer specificity for an antigen.

[0055] More specifically, the light chain variable region comprises the amino acid sequence of SEQ ID NO: 19.

[0056] More specifically, the anti-HER2 antibody of the present invention comprises a heavy chain comprising the amino acid sequence of SEQ ID NO: 20.

[0057] More specifically, the anti-HER2 antibody of the present invention comprises a light chain comprising the amino acid sequence of SEQ ID NO: 21.

[0058] According to a specific embodiment of the present invention, the small molecule anticancer agent used in the present invention is selected from the group consisting of Topotecan, Irinotecan, Camptothecin, Belotecan, Lurtotecan, a compound represented by the following chemical formula 1, and a pharmaceutically acceptable salt thereof:

[0059] Chemical Formula 1

[0060]

[0061] In the above chemical formula, R1 and R2 are each independently hydrogen or C1-C3 alkyl, and X is halogen.

[0062] The term “alkyl” as used herein means a straight-chain or branched saturated hydrocarbon group, and includes, for example, methyl, ethyl, propyl, isopropyl, etc. C1-C3 alkyl means an alkyl group having an alkyl unit having 1 to 3 carbon atoms, and when C1-C3 alkyl is substituted, the carbon number of the substituent is not included.

[0063] As used herein, the term “halogen” refers to a halogen group element, including, for example, fluoro, chloro, bromo, and iodo.

[0064] More specifically, in the chemical formula, R1 is C1 alkyl, R2 is C2 alkyl, and X is fluoro. The compound of formula 1, where R1 is C1 alkyl(methyl), R2 is C2 alkyl(ethyl), and X is fluoro, is Exatecan (C 24 H 22 FN3O4).

[0065] As used herein, the term “pharmaceutically acceptable salt” includes salts derived from pharmaceutically acceptable inorganic acids, organic acids, or bases. Examples of suitable acids include hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, perchloric acid, fumaric acid, maleic acid, phosphoric acid, glycolic acid, lactic acid, salicylic acid, succinic acid, toluene-p-sulfonic acid, tartaric acid, acetic acid, trifluoroacetic acid, citric acid, methanesulfonic acid, formic acid, benzoic acid, malonic acid, naphthalene-2-sulfonic acid, benzenesulfonic acid, and the like. Salts derived from suitable bases may include alkali metals such as sodium, alkaline earth metals such as magnesium, and ammonium.

[0066] The term “prevention” as used herein means inhibiting the occurrence of a disease or condition in a subject who has not been diagnosed as having the disease or condition but is susceptible to such disease or condition.

[0067] As used herein, the term “treatment” means (a) inhibiting the development of a disease, condition, or symptom; (b) alleviating the disease, condition, or symptom; or (c) eliminating the disease, condition, or symptom. When the composition of the present invention is administered to a subject, it suppresses the proliferation of a tumor, specifically a HER2-positive tumor, and promotes its death, thereby inhibiting the development of, eliminating, or alleviating symptoms caused by the tumor. Therefore, the composition of the present invention may be a composition for treating these diseases on its own, or may be administered together with other pharmacological ingredients and used as an adjuvant treatment for the diseases. Accordingly, the terms “treatment” or “therapeutic agent” as used herein include the meaning of “adjuvant treatment” or “adjuvant treatment agent.”

[0068] As used herein, the term “administration” or “administer” refers to an act of directly administering a therapeutically effective amount of the composition of the present invention to a subject, so that the effective amount is formed at a substantially same level in the body of the subject.

[0069] In the present invention, the term “therapeutically effective amount” means the content of a composition in which the pharmacological ingredient in the composition is contained in an amount sufficient to provide a therapeutic or preventive effect to a subject to whom the pharmaceutical composition of the present invention is to be administered, and includes a “prophylactically effective amount”.

[0070] The term “subject” as used herein includes, without limitation, a human, mouse, rat, guinea pig, dog, cat, horse, cow, pig, monkey, chimpanzee, baboon, or rhesus macaque. Specifically, the subject of the present invention is a human.

[0071] According to a specific embodiment of the present invention, the anti-HER2 antibody or antigen-binding fragment thereof and the low-molecular-weight anticancer agent are linked by a cleavable linker.

[0072] The term "linker" as used herein refers to a synthetic peptide or small molecule compound that serves as a chemical linkage that physically connects two molecules by forming covalent bonds at their respective ends. The linker linearly connects a first molecule (e.g., an anti-HER2 antibody or antigen-binding fragment thereof) and a second molecule (e.g., a small molecule anticancer agent), each of which has independent biological activity.

[0073] The term “cleavable linker” as used herein means a linker that can be cleaved under certain in vivo conditions, and specifically, a linker in which the covalent bond is broken and the connection between the first molecule and the second molecule is cleaved when exposed to a stimulus such as a decomposing enzyme, a pH range, or ultraviolet light.

[0074] According to a more specific embodiment of the present invention, the cleavable linker is a self-cleavable linker or an enzymatically-cleavable linker.

[0075] As used herein, the term “self-cleaving linker” refers to a linker that is designed to self-cleave through a continuous degradation reaction upon exposure to a specific stimulus. A self-cleaving linker is one in which a portion of the structure is removed by a primary trigger (e.g., enzyme exposure, pH change, etc.), after which the entire structure spontaneously collapses, physically completely separating the first molecule from the second molecule. Examples of self-cleaving linkers include, but are not limited to, p-Aminobenzyloxycarbonyl (PABC), p-Hydroxybenzyl alcohol (pHBA), and disulfide-p-aminobenzyl (PAB) linkers.

[0076] As used herein, the term “enzyme-cleavable linker” refers to a chemical linkage that is selectively recognized and cleaved by a specific enzyme (e.g., an intracellular lysosomal protease or an endosomal protease). Such linkers are designed to maintain a stable structure in normal tissues, but to be cleaved by an active enzyme within a target cell to release the drug. Examples of enzyme-cleavable linkers include, but are not limited to, Gly-Gly-Phe-Gly (GGFG), valine-citrulline (Val-Cit), Val-Ala (VA), Phe-Lys (FK), and mc-Val-Cit-PABA linkers. More specifically, the enzyme-cleavable linker used in the present invention may be Gly-Gly-Phe-Gly (GGFG). The GGFG linker is cleaved by catepepsis enzymes, thereby controlling drug release within cancer cells and playing an important role in minimizing damage to normal cells.

[0077] According to one embodiment of the present invention, when the anti-HER2 antibody of the present invention and the small molecule anticancer agent represented by the above-described chemical formula 1 are linked by a GGFG linker, -(succinimide-3-yl-N)-(CH2)nC(=O)- may be linked to the N-terminus of the GGFG linker to link with a cysteine ​​of the heavy chain constant region of the anti-HER2 antibody, and NH-(CH2)m-OCH2-C(=O)- may be linked to the C-terminus of the GGFG linker to link with an amine group of the small molecule anticancer agent represented by the chemical formula 1. In this case, in the antibody-drug conjugate of the present invention, the antibody and the drug may be linked by a linker represented by the following chemical formula 2:

[0078] Chemical Formula 2

[0079] -(Succinimide-3-yl-N)-(CH2)nC(=O)-GGFG-NH-(CH2)m-OCH2-C(=O)-

[0080] In the above chemical formula 2, n is an integer from 3 to 7, and m is an integer from 1 to 4. More specifically, n is an integer from 4 to 7, and m is an integer from 1 to 3, and most specifically, n is 5 and m is 1.

[0081]

[0082] According to a specific embodiment of the present invention, the cancer that can be prevented or treated with the composition of the present invention is a HER2 positive tumor.

[0083] The term “HER2 positive tumor” as used herein refers to a cancer that includes the expression or activation of HER2, and further encompasses cancer types in which cancer cells exhibiting HER2 gene dysregulation have been identified. Therefore, HER2 positive tumor is used with the same meaning as “HER2-dependent tumor”, and is used as a concept opposite to “HER2 independent tumor” or “HER2 negative tumor”. HER2 positive tumor includes, but is not limited to, breast cancer, stomach cancer, ovarian cancer, bladder cancer, and pancreatic cancer, and includes all malignant tumors that express HER2 on their surface to a degree that the HER2 protein or the gene encoding it can significantly function as a therapeutic target or diagnostic marker.

[0084] According to another aspect of the present invention, the present invention provides a pharmaceutical composition for preventing or treating cancer, comprising a fusion protein comprising a CD80 protein or a fragment thereof and an IL-2 protein or a variant thereof as an active ingredient, wherein the fusion protein is administered in combination with a conjugate of an anti-HER2 antibody or an antigen-binding fragment thereof and a low-molecular-weight anticancer agent.

[0085] According to another aspect of the present invention, the present invention provides a method for preventing or treating cancer, comprising administering to a subject a fusion protein comprising a CD80 protein or a fragment thereof and an IL-2 protein or a variant thereof, wherein the fusion protein is administered in combination with a conjugate of an anti-HER2 antibody or an antigen-binding fragment thereof and a small molecule anticancer agent.

[0086] According to another aspect of the present invention, the present invention provides a pharmaceutical composition for preventing or treating cancer, comprising a conjugate of an anti-HER2 antibody or an antigen-binding fragment thereof and a low-molecular-weight anticancer agent as an active ingredient, wherein the conjugate is administered in combination with a fusion protein comprising a CD80 protein or a fragment thereof and an IL-2 protein or a variant thereof.

[0087] According to another aspect of the present invention, the present invention provides a method for preventing or treating cancer, comprising administering to a subject a conjugate of an anti-HER2 antibody or an antigen-binding fragment thereof and a small molecule anticancer agent, wherein the conjugate is administered in combination with a fusion protein comprising a CD80 protein or a fragment thereof and an IL-2 protein or a variant thereof.

[0088] The fusion protein, antibody-drug conjugate used in the present invention, and cancer that can be prevented or treated through the same have already been described above, so their description is omitted to avoid excessive duplication.

[0089] As described above, the fusion protein of the present invention and the antibody-drug conjugate exhibited a remarkable synergistic effect when administered together, and therefore, the two pharmacological components can be administered together to maximize the anticancer effect and improve the patient's survival rate. The combined administration can be performed by administering a single formulation containing both the fusion protein of the present invention and the antibody-drug conjugate, or by administering separate formulations containing each compound individually simultaneously or sequentially in any order with an appropriate time difference.

[0090]

[0091] The features and advantages of the present invention are summarized as follows:

[0092] (a) The present invention provides a composition for preventing or treating cancer, comprising a fusion protein comprising a CD80 protein and an IL-2 protein; and an anti-HER2 antibody-drug conjugate as active ingredients.

[0093] (b) The present invention achieves a synergistic anticancer effect by conjugating Trastuzumab, which has a low initial treatment response and a high proportion of resistant patients, to Exatecan, a topoisomerase I inhibitor, and then co-administering the conjugate with a fusion protein containing CD80 protein and IL-2 protein.

[0094] (c) Accordingly, the present invention can maximize the effectiveness of trastuzumab as a therapeutic antibody, ultimately significantly improving the survival rate of patients.

[0095]

[0096] Figure 1 is an embodiment of the fusion protein of the present invention (GI-102) (Figure 1a) and an antibody-drug conjugate (ENHERTU ® )(Fig. 1b) is a diagram schematically illustrating the structure of each.

[0097] Figure 2 shows the effects of GI-102 and ENHERTU in a xenograft breast cancer animal model using BALB / c nude mice. ®This figure shows the degree of tumor growth inhibition when administered alone or in combination, and shows the change in tumor volume (Fig. 2a) and tumor growth inhibition rate (TGI %) of each individual (Fig. 2b).

[0098] Figure 3 shows the effect of GI-102 and ENHERTU in a xenograft breast cancer model. ® This figure shows the results of measuring the extent of tumor growth in individual experimental animals when administered alone or in combination.

[0099]

[0100] Hereinafter, the present invention will be described in more detail through examples. These examples are intended solely to illustrate the present invention more specifically, and it will be apparent to those skilled in the art that the scope of the present invention is not limited by these examples, in accordance with the gist of the present invention.

[0101]

[0102] Example

[0103] Manufacturing Example 1. Manufacturing of GI-102

[0104] To produce a fusion protein (GI-102) comprising a human CD80 fragment, an Fc domain, and an IL-2 variant (3M) with three amino acid substitutions (R38A, F42A, E61R), a polynucleotide comprising the base sequence (SEQ ID NO: 11) encoding a fusion protein comprising a signal peptide (SEQ ID NO: 1), a CD80 fragment (SEQ ID NO: 3), an Ig hinge (SEQ ID NO: 4), an Fc domain (SEQ ID NO: 5), a linker (SEQ ID NO: 6), and an IL-2 variant (SEQ ID NO: 9) in this order from the N-terminus was synthesized through the Invitrogen GeneArt Gene Synthesis service of Thermo Fisher Scientific and loaded into the pcDNA3.4 vector (Table 1).

[0105] 구분서열정보서열번호signal peptide (TPA)MDAMLRGLCCVLLLCGAVFVSPSHA1CD80MGHTRRQGTSPSKCPYLNFFQLLVLAGLSHFCSGVIHVTKEVKEVATLSCGHNVSVEELAQTRIYWQKEKKMVLTMMSGDMNIWPEYKNRTIFDITNNLSIVILALRPSDEGTYECVVLKYEKDAFKREHLAEVTLSVKADFPTPSISDFEIPTSNIRRIICSTSGGFPEPHLSWLENGEELNAINTTVSQDPETELYAVSSKLDFNMTTNHSFMCLIKYGHLRVNQTFNWNTTKQEHFPDNLLPSWAITLISVNGIFVICCLTYCFAPRCRERRRNERLRRESVRPV2CD80(hB7-1:35-242)VIHVTKEVKEVATLSCGHNVSVEELAQTRIYWQKEKKMVLTMMSGDMNIWPEYKNRTIFDITNNLSIVILALRPSDEGTYECVVLKYEKDAFKREHLAEVTLSVKADFPTPSISDFEIPTSNIRRIICSTSGGFPEPHLSWLENGEELNAINTTVSQDPETELYAVSSKLDFNMTTNHSFMCLIKYGHLRVNQTFNWNTTKQEHFPDN3hingeGSGGGGSGGGGSGGGGSAESKYGPPCPPCP4ImmunoglobulinFcAPEAAGGPSVFLFPPKPKDQLMISRTPEVTCVVVDVSQEDPEVQFNWYVDGVEVHNAKTKPREEQFNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKGLPSSIEKTISKAKGQPREPQVYTLPPSQEEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSRLTVDKSRWQEGNVFSCSVLHEALHNHYTQKSLSLSLG5linkerGGGGS6hIL2APTSSSTKKTQLQLEHLLLDLQMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKPLEEVLNLAQSKNFHLRPRDLISNINVIVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIISTLT7hIL2v2APTSSSTKKTQLQLEHLLLDLQMILNGINNYKNPKLTAMLTAKFYMPKKATELKHLQCLEEELKPLEEVLNLAQSKNFHLRPRDLISNINVIVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIISTLT8hIL2v3APTSSSTKKTQLQLEHLLLDLQMILNGINNYKNPKLTAMLTAKFYMPKKATELKHLQCLERELKPLEEVLNLAQSKNFHLRPRDLISNINVIVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIISTLT9CD80-IgG4Fc-IL2v3VIHVTKEVKEVATLSCGHNVSVEELAQTRIYWQKEKKMVLTMMSGDMNIWPEYKNRTIFDITNNLSIVILALRPSDEGTYECVVLKYEKDAFKREHLAEVTLSVKADFPTPSISDFEIPTSNIRRIICSTSGGFPEPHLSWLENGEELNAINTTVSQDPETELYAVSSKLDFNMTTNHSFMCLIKYGHLRVNQTFNWNTTKQEHFPDNGSGGGGSGGGGSGGGGSAESKYGPPCPPCPAPEAAGGPSVFLFPPKPKDQLMISRTPEVTCVVVDVSQEDPEVQFNWYVDGVEVHNAKTKPREEQFNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKGLPSSIEKTISKAKGQPREPQVYTLPPSQEEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSRLTVDKSRWQEGNVFSCSVLHEALHNHYTQKSLSLSLGGGGGSAPTSSSTKKTQLQLEHLLLDLQMILNGINNYKNPKLTAMLTAKFYMPKKATELKHLQCLERELKPLEEVLNLAQSKNFHLRPRDLISNINVIVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIISTLT10CD80-IgG4 Fc-IL2v3(nucleotide)atggatgcta tgctgagagg cctgtgttgc gtgctgctgc tgtgtggcgc tgtgttcgtg tctccttctc acgctgtgat ccacgtgacc aaagaagtga aagaggtcgc cacactgtcc tgcggccaca acgtttcagt ggaagaactg gcccagacca ggatctactg gcagaaagaa aagaaaatgg tgctgaccat gatgtccggc gacatgaaca tctggcctga gtacaagaac cggaccatct tcgacatcac caacaacctg tccatcgtga ttctggccct gaggccttct gatgagggca cctatgagtg cgtggtgctgaagtacgaga aggacgcctt caagcgcgag cacctggctg aagtgacact gtccgtgaag gccgactttc ccacaccttc catctccgac ttcgagatcc ctacctccaa catccggcgg atcatctgtt ctacctctgg cggctttcct gagcctcacc tgtcttggct ggaaaacggc gaggaactga acgccatcaa caccaccgtg tctcaggacc ccgaaaccga gctgtacgct gtgtcctcca agctggactt caacatgacc accaaccaca gcttcatgtg cctgattaag tacggccacc tgagagtgaa ccagaccttc aactggaaca ccaccaagca agagcacttc cctgacaatg gatctggcgg cggaggttct ggcggaggtg gaagcggagg cggaggatct gctgagtcta agtatggccc tccttgtcct ccatgtcctg ctccagaagc tgctggcgga ccctctgtgt tcctgtttcc tccaaagcct aaggaccagc tcatgatctc tcggacaccc gaagtgacct gcgtggtggt ggatgtgtct caagaggacc ctgaggtgca gttcaattgg tacgtggacg gcgtggaagt gcacaacgcc aagaccaagc ctagagagga acagttcaac tccacctaca gagtggtgtc cgtgctgacc gtgctgcacc aggattggct gaacggcaaa gagtacaagt gcaaggtgtc caacaagggc ctgccttcca gcatcgaaaa gaccatctcc aaggctaagg gccagcctag ggaaccccag gtttacaccc tgcctccaag ccaagaggaa atgaccaaga accaggtgtc cctgacctgc ctggtcaagg gcttctaccc ttccgacatt gccgtggaatgggagtccaa tggccagcct gagaacaact acaagaccac acctcctgtg ctggactccg acggctcctt ctttctgtac tctcgcctga ccgtggacaa gtctagatgg caagagggca acgtgttctc ctgctctgtg ctgcacgagg ccctgcacaa tcactacacc cagaagtccc tgtctctgtc tcttggaggt ggtggcggtt ctgcccctac cagctcctct accaagaaaa cccagctcca gttggagcat ctgctgctgg acctccagat gattctgaac gggatcaaca actataagaa ccccaagctg accgccatgc tgaccgctaa gttctacatg cccaagaagg ccaccgagct gaagcacctc cagtgcctgg aaagggaact gaagcccctg gaagaggtgc tgaatctggc ccagtccaag aacttccacc tgaggccacg ggacctgatc agcaacatca acgtgatcgt gctggaactg aagggctccg agacaacctt tatgtgcgag tacgccgacg agacagccac catcgtggaa tttctgaacc ggtggatcac cttctgccag agcatcatct ccacactgac c11

[0106]

[0107] In addition, the above vector was expressed in CHO cells (Expi-CHO TM ) was introduced to express the fusion protein of sequence number 10. The stable cell line expressing the fusion protein of sequence number 10 was supplied with feed medium at a ratio of 7.0% (v / v) every other day from the 3rd to the 11th day of culture in a fed-batch manner, and the culture medium was recovered on the 12th day. The fusion protein (GI-102) was purified from the recovered culture medium through chromatography.

[0108]

[0109] Manufacturing Example 2: Establishment of a xenograft breast cancer model using BALB / c nude mice.

[0110] Seven days before transplanting the human breast cancer cell line BT-474 into mice, 17β-estradiol (NE-121, Innovative research of America, USA) was first transplanted in the form of pellets. The 17β-estradiol pellets were inserted using a dedicated trochar (trochar, MP-182, Innovative research of America, USA). Specifically, after mounting the pellet on the needle of the trochar, the mouse was fixed and the skin on the left flank, the transplantation site, was pulled to expose it. The pellet was then inserted subcutaneously using the trochar.

[0111] BT-474 cells were collected 7 days after estrogen pellet implantation and were seeded at 1 x 10 6 Cell suspension was prepared at a concentration of 0.05 mL. 0.05 mL of Matrigel matrix phenol red-free (356231, Corning, USA) was mixed here, and the mixed solution was filled into a disposable syringe (31G, Cat. 328820, BD, USA) and 0.1 mL was injected subcutaneously into the right dorsal region of the mice to transplant the cells. General symptoms were observed once a day during the engraftment and tumor growth period after cell transplantation. After a certain period, the tumor volume was measured in individuals without any health problems, and the average tumor volume by group was 60 - 100 mm. 3 To reach the target, they were divided into 4 groups, 10 animals per group. After group division, ENHERTU ® (398071, Daiichi Sankyo) was administered intravenously (IV) once at a concentration of 2 mg / kg, and GI-102 was administered subcutaneously (SC) once a week at a concentration of 3 mg / kg.

[0112] ENHERTU during the exam period ®was administered once in total, and GI-102 was administered three times in total, and the tumor size was measured for up to 18 days after administration. During the observation period, the maximum length (L) and perpendicular width (W) of the tumor were measured three times a week using a caliper (Digital caliper, Mitutoyo, Japan), and the tumor volume (TV) was calculated using the following equation.

[0113] TV (mm 3 ) = (W2 x L) / 2

[0114] TGI = (1-(Ti-T0) / (Vi-V0))*100

[0115] The pre-administration tumor volume (T0) of each individual was determined based on the values ​​measured at the time of group separation. Body weight, tumor volume, and tumor weight obtained during the experiment were analyzed using Prism (Graphpad, version 7) software. To assess statistical significance between each experimental group (G2 to G4), a one-way analysis of variance (ANOVA) followed by a Dunnett's multiple-test was performed. Statistical significance was expressed according to the following criteria:

[0116] * p<0.5, ** p<0.1, **p<0.01, ***p<0.001, ****p<0.000

[0117]

[0118] Experimental Example 1: GI-102 and ENHERTU in a xenograft breast cancer model ® Evaluation of antitumor effects through combined administration

[0119] In this experiment, GI-102, ENHERTU ®The tumor growth inhibition effect (TGI%) according to single administration and combination administration was compared and analyzed. In the GI-102 single administration group, TGI% of 30% or more was observed in 4 animals, 50% or more in 4 animals, and 80% or more in 2 animals (Fig. 1b). ENHERTU ® In the single-administration group, 6 animals showed a TGI of 30% or more, 5 animals showed a tumor growth inhibition effect of 50% or more, and 1 animal showed a tumor growth inhibition effect of 80% or more. GI-102 and ENHERTU ® In the combination treatment group, 9 animals showed a TGI of 30% or more, 9 animals showed a TGI of 50% or more, and 6 animals showed a TGI of 80% or more, confirming a marked increase in the antitumor effect when used in combination. In addition, the combination treatment group showed a significant decrease in tumor size and an increased tumor growth inhibitory effect compared to the control group (hIgG4) and each monotherapy group (Fig. 1).

[0120] Antibody-drug conjugate (ENHERTU) ®

[0121]

[0122] Experimental Example 2: Analysis of tumor growth patterns in individual experimental animals in each experimental group.

[0123] The tumor size of each individual in each experimental group was measured, and GI-102 and ENHERTU ® The monotherapy group did not show a significant increase in tumor size compared to the control group (IgG4), and an excellent tumor growth inhibition effect was observed in the combination therapy group of the two drugs (Figure 2).

[0124]

[0125] While specific aspects of the present invention have been described in detail above, it should be apparent to those skilled in the art that these specific descriptions are merely preferred embodiments and do not limit the scope of the present invention. Therefore, the substantial scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A pharmaceutical composition for preventing or treating cancer, comprising a fusion protein comprising a CD80 protein or a fragment thereof and an IL-2 protein or a variant thereof; and a conjugate of an anti-HER2 antibody or an antigen-binding fragment thereof and a low-molecular-weight anticancer agent as active ingredients.

2. A composition according to claim 1, characterized in that the fragment of the CD80 protein is an extracellular domain of the CD80 protein.

3. A composition according to claim 1, characterized in that the IL-2 protein variant is a variant comprising a substitution of one or more amino acids among the 38th, 42nd, 45th, 61st, and 72nd amino acids of the amino acid sequence of SEQ ID NO:

7.

4. A composition according to claim 1, wherein the anti-HER2 antibody or antigen-binding fragment thereof comprises a heavy chain variable region comprising an HCDR1 region having an amino acid sequence of SEQ ID NO: 12; an HCDR2 region having an amino acid sequence of SEQ ID NO: 13; and an HCDR3 region having an amino acid sequence of SEQ ID NO:

14.

5. A composition according to claim 4, characterized in that the heavy chain variable region comprises an amino acid sequence of SEQ ID NO:

15.

6. A composition according to claim 1, wherein the anti-HER2 antibody or antigen-binding fragment thereof comprises a light chain variable region comprising an LCDR1 region having an amino acid sequence of SEQ ID NO: 16; an LCDR2 region having an amino acid sequence of SEQ ID NO: 17; and an LCDR3 region having an amino acid sequence of SEQ ID NO:

18.

7. A composition according to claim 6, characterized in that the light chain variable region comprises an amino acid sequence of SEQ ID NO:

19.

8. In the first paragraph, the composition is characterized in that the low-molecular-weight anticancer agent is selected from the group consisting of Topotecan, Irinotecan, Camptothecin, Belotecan, Lurtotecan, a compound represented by the following chemical formula 1, and a pharmaceutically acceptable salt thereof: Chemical Formula 1 In the above chemical formula, R1 and R2 are each independently hydrogen or C1-C3 alkyl, and X is halogen.

9. A composition according to claim 1, wherein the anti-HER2 antibody or antigen-binding fragment thereof and the low-molecular-weight anticancer agent are linked by a cleavable linker.

10. A composition according to claim 9, wherein the cleavable linker is a self-cleavable linker or an enzymatically-cleavable linker.

11. A composition according to claim 1, characterized in that the cancer is a HER2-positive tumor.

12. A pharmaceutical composition for preventing or treating cancer, comprising a fusion protein comprising a CD80 protein or a fragment thereof and an IL-2 protein or a variant thereof as an active ingredient, wherein the fusion protein is administered in combination with a conjugate of an anti-HER2 antibody or an antigen-binding fragment thereof and a low-molecular-weight anticancer agent.

13. A pharmaceutical composition for preventing or treating cancer, comprising a conjugate of an anti-HER2 antibody or an antigen-binding fragment thereof and a low-molecular-weight anticancer agent as an active ingredient, wherein the conjugate is administered in combination with a fusion protein comprising a CD80 protein or a fragment thereof and an IL-2 protein or a variant thereof.

Images