JP2012025694A - Cancer therapeutic agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cancer therapeutic agent comprising an antibody to a cancer-specific membrane antigen achieving reduction in the invalid examples of a trastuzumab.SOLUTION: The cancer therapeutic agent comprises an antibody having antibody-dependent cell cytotoxicity activity to a cancer-specific membrane antigen expressed in epithelial cancer cells. The cancer therapeutic agent is (1) used to a patient with epithelial cancer in which the cancer-specific membrane antigen is positive and the ligand to KLRG1 is positive and is (2) used combinedly with a KLRG1 antagonist.

Description

  The present invention relates to a cancer therapeutic agent comprising an antibody against a cancer-specific membrane antigen expressed in epithelial cancer cells. Furthermore, the present invention relates to a pharmaceutical composition comprising an antibody against the cancer-specific membrane antigen and a KLRG1 antagonist, and a KLRG1 antagonist that enhances the antibody-dependent cytotoxic activity of the cancer therapeutic agent.

  In recent years, the number of breast cancer cases and deaths in Japan has increased significantly. Until now, breast cancer has tended to determine treatment methods other than surgery depending on the expression status of estrogen receptor (ER) and progesterone receptor (PgR). Pharmacotherapy such as hormone therapy and anticancer drug therapy is useful, and the response rate and survival rate have been improved. However, approximately 50% of human epidermal growth factor receptor-related 2 (HER2) positive breast cancers were negative for hormone receptors and excluded from hormone therapy. Recently, molecular targeted therapies such as antibody therapy centered on trastuzumab for HER2-positive breast cancer have been performed, and its usefulness has been demonstrated, and it is expected as a promising therapeutic method in the future.

Breast cancer cells express various growth factors and their receptors, forming a signal transduction system related to growth. The oncogene HER2 identified in 1984 is one of them, and is a member of the human epidermal growth factor receptor (EGFR, HER) family.
Receptors are transmembrane glycoproteins, and HER1, HER2, HER3, and HER4 are present due to structural similarity (Non-patent Document 1). The EGF receptor family contributes to signal transduction through dimer formation, and it is thought that a receptor to which a ligand is bound contributes to signal transduction by forming a dimer with another receptor.

  HER2 / neu that defines the HER2 receptor is considered to be one of proto-oncogenes and exists on chromosome 17 (17q21.1) (Non-patent Document 2). Amplification and overexpression of the HER2 / neu gene have been observed in various cancers such as breast cancer, ovarian cancer, lung cancer, and gastric cancer. HER2-positive breast cancer accounts for 20% to 30% of all breast cancers. The expression of this gene is very weak in normal adult tissues. Its natural history is unique, with rapid recurrence if no systemic therapy is given, and since 1987, when HER2 amplification was reported to correlate with poor prognosis of breast cancer, many studies have shown progress in HER2-positive metastatic breast cancer Has been shown to be bad.

  In 1986, anti-HER2 monoclonal antibody was shown to inhibit the malignant phenotype of neu-transformed cells, leading to the development of trastuzumab targeting HER2. The mouse monoclonal antibody mu4D5 against the extracellular domain of the HER2 receptor, which was the prototype of trastuzumab, has been shown to inhibit growth of HER2-positive tumor cell lines in vitro (Non-patent Document 3). In addition, antibody-dependent cell cytotoxicity (ADCC) of mouse spleen cells against HER2-positive human breast cancer cell line SKBR3 is enhanced by mouse monoclonal antibodies, and ADCC activity is also antitumor in vivo. There is also a report that it contributes to the effect (Non-Patent Document 4). However, in clinical application, the appearance of human anti-mouse antibody (HAMA) becomes a problem when mouse antibodies are used as they are. Therefore, trastuzumab (trade name: Herceptin (registered trademark)) was produced as a humanized antibody in which only the variable region, which is the antigen-binding site of the mouse monoclonal antibody against the extracellular domain of the HER2 receptor, was transplanted into the constant region of human IgG1. ).

  HER2 triggers various signaling pathway networks including PI3K and MAPK, but trastuzumab suppresses this signaling pathway by binding to the HER2 receptor, leading to cell cycle arrest, apoptosis, and angiogenesis inhibition Thus, it is considered that the tumor cell growth inhibitory effect is directly exhibited. In addition, inhibition of Src tyrosine kinase, concomitant activation of PTEN, and dephosphorylation of Akt have been reported. Furthermore, it has been shown that Fc receptors expressed on immune cells including NK cells bind to the Fc part of trastuzumab bound to tumor cells and show tumor cell killing effect (ADCC activity) (non-patent literature) 5 to 8). These direct tumor cell growth-inhibiting effects and ADCC activity are considered to be the main mechanism of action of trastuzumab.

  Trastuzumab targets HER2, and its therapeutic effect varies greatly depending on the level of HER2 protein expression. It is known that the positive rate varies greatly depending on the measurement method and materials, but in order to investigate HER2 protein overexpression and DNA amplification, immunohistochemical method (IHC method) and fluoresence in situ hybridization ( FISH) is widely performed. In addition, trastuzumab has been shown to be highly effective when used as an adjuvant therapy in several large-scale clinical trials, including the HERA trial.

Various studies to date have shown that inhibition of HER2 by trastuzumab administration has a significant effect on the natural course of breast cancer. However, it has been found that trastuzumab does not alter the natural course of all HER2-overexpressing breast cancers, and cases responding to the first dose of trastuzumab alone are less than about 1/3 of HER2-overexpressing breast cancer. ing. Similarly, in the case of microscopic metastatic cancer, a significant proportion of tumors are suggested to be resistant to trastuzumab. However, the mechanism of trastuzumab resistance has not been clearly elucidated. Current resistance mechanisms include: (1) insufficient trastuzumab reach, resulting in insufficient inhibition of extracellular region of HER2, (2) decreased HER2 expression, (3) regulation of HER2 function downstream Factor changes (such as p27 ^kip1 decrease, loss or inactivation of PTEN), (4) signal transduction by alternative pathways (insulin-like growth factor I receptor: overexpression of IGF1R), ( 5) It has been suggested that there is a possibility of a decrease in immunity, especially a decrease in ADCC activity.

  The study on immune capacity and resistance mechanism listed in (5) above is not very active. In recent years, the function of NK cells, which are factors involved in ADCC activity, which is one of the main mechanisms of action of trastuzumab, has been clarified. Inhibitory receptors are expressed in NK cells, one of which has been identified as killer cell lectin-like receptor G1 (KLRG1). Until now, most of the ligands of inhibitory receptors revealed for NK cells have been related to MHC class I molecules. In 2006, M. Ito et al. Reported that the ligand for KLRG1 was other than MHC class I molecules. It was reported.

KLRG1 was discovered as a functional molecule MAFA (mast cell function-associated antigen) expressed in the rat basophilic leukemia cell line RBL-2H3 (Non-patent Document 9). This KLRG1 suppresses degranulation by Fc receptor stimulation by cross-linking KLRG1 with anti-KLRG1 antibody in RBL-2H3 cells. From the cDNA cloning of rat KLRG1, it is a homodimer of a type II transmembrane protein having a C-type lectin-like structure in the extracellular region and an ITIM (immunoreceptor tyrosine-based inhibitory motif) in the intracellular region. Reported by Pecht et al. (Non-Patent Document 10). In humans and mice, KLRG1 is expressed in a part of NK cells and T cells (Non-patent Documents 11 to 13), but it is known that expression is observed in about 50% of peripheral blood NK cells in healthy individuals.

  In recent years, antibody drugs using ADCC activity such as trastuzumab have been widely used. For example, the anti-human CD20 antibody rituximab used to treat non-Hodgkin lymphoma, the anti-human CD52 antibody alemtuzumab used to treat B-cell malignancies, and the anti-human EGFR antibody cetuximab used to treat colorectal cancer Is mentioned. However, these antibody drugs do not show efficacy in all patients, for example, 30-50% of low-grade non-Hodgkin lymphoma patients do not respond to rituximab.

In contrast, Patent Document 1 describes a method for increasing the effectiveness of therapeutic antibodies by blocking inhibitory receptors related to MHC class I molecules on NK cells. However, in recent years, KLRG1, LAIR-1 (leukocyte-associated immunoglobulin-like receptor 1), NKR-P1A (CD161), etc. have been found as inhibitory receptors on NK cells in addition to those related to MHC class 1 molecules. These ligands have also been clarified (Non-Patent Documents 14 to 15).

International Publication No. 2005/009465 Pamphlet

Pinkas-Kramarski, R., I. Arloy and Y. Yarden (1997) ErbB receptors and EGF-like ligands: cell lineage determination and oncogenesis through combinatorial signaling.J Mammary Gland Biol Neoplasia, 2: 97-107. Schechter, AL, DF Stern, L. Vaidyanathan, SJ Decker, JA Drebin, MI Greene and RA Weinberg (1984) The neu oncogene: an erb-B-related gene encoding a 185,000-Mr tumour antigen.Nature, 312: 513- 516. Hudziak RM, Lewis GD, Winget M, Fendly BM, Shepard HM, Ullrich A (1989) p185HER2 monoclonal antibody has antiproliferative effects in vitro and sensitizes human breast tumor cells to tumor necrosis factor. Mol Cell Biol, 9 (3): 1165- 72. Piccart-Gebhart MJ, Procter M, Leyland-Jones B, Goldhirsch A, Untch M, Smith I, Gianni L, Baselga J, Bell R, Jackisch C, Cameron D, Dowsett M, Barrios CH, Steger G, Huang CS, Andersson M, Inbar M, Lichinitser M, Lang I, Nitz U, Iwata H, Thomssen C, Lohrisch C, Suter TM, Ruschoff J, Suto T, Greatorex V, Ward C, Straehle C, McFadden E, Dolci MS, Gelber RD; Herceptin Adjuvant (HERA) Trial Study Team (2005) Trastuzumab after adjuvant chemotherapy in HER2-positive breast cancer.N Engl J Med, 353 (16): 1659-72 Clynes RA, Towers TL, Presta LG, Ravetch JV (2000) Inhibitory Fc receptors modulate in vivo cytoxicity against tumor targets. Nat Med, 6 (4): 443-6. Izumi Y, Xu L, di Tomaso E, Fukumura D, Jain RK (2002) Tumour biology: herceptin acts as an anti-angiogenic cocktail. Nature, 416 (6878): 279-80 Gennari R, Menard S, Fagnoni F, Ponchio L, Scelsi M, Tagliabue E, Castiglioni F, Villani L, Magalotti C, Gibelli N, Oliviero B, Ballardini B, Da Prada G, Zambelli A, Costa A (2004) Pilot study of the mechanism of action of preoperative trastuzumab in patients with primary operable breast tumors overexpressing HER2. Clin Cancer Res., 10 (17): 5650-5 Barok, et al., (2007) Trastuzumab causes antibody-dependent cellular cytotoxicity-mediated growth inhibition of submacroscopic JIMT-1 breast cancer xenografts despite intrinsic drug resistance.Molecular Cancer Therapeutics, 6: 2065-2072. Ortega Soto E, Pecht I (1988) A monoclonal antibody that inhibits secretion from rat basophilic leukemia cells and binds to a novel membrane component.J Immunol, 141 (12): 4324-32. Abramson J, Xu R, Pecht I (2002) An unusual inhibitory receptor--the mast cell function-associated antigen (MAFA). Mol Immunol, 38 (16-18): 1307-13. Hanke T, Corral L, Vance RE, Raulet DH (1998) 2F1 antigen, the mouse homolog of the rat "mast cell function-associated antigen", is a lectin-like type II transmembrane receptor expressed by natural killer cells. Eur J Immunol ., 28 (12): 4409-17 Butcher S, Arney KL, Cook GP (1998) MAFA-L, an ITIM-containing receptor encoded by the human NK cell gene complex and expressed by basophils and NK cells.Eur J Immunol., 28 (11): 3755-62 Blaser C, Kaufmann M, Pircher H (1998) Virus-activated CD8 T cells and lymphokine-activated NK cells express the mast cell function-associated antigen, an inhibitory C-type lectin.J Immunol., 161 (12): 6451- Four David B. Rosen (2005) J Immunol., 176: 7796-7799 Experimental Medicine (2007) June Vol.25 No.9, 1282-1398 Disorder of NK cell recognition

  The present invention relates to a cancer-specific membrane antigen, which is administered by a novel method which makes it possible to reduce ineffective cases of a cancer therapeutic agent containing an antibody having antibody-dependent cytotoxic activity. Providing a cancer therapeutic agent containing an antibody was an issue to be solved.

  The present inventors paid attention to receptors that suppress cytotoxic activity on NK cells for the purpose of increasing the therapeutic effect of anticancer agents utilizing antibody-dependent cytotoxic activity such as the above-mentioned cancer therapeutic agents. Tumor cells are mutated or deficient in MHC class I molecules, and as a result of investigations other than inhibitory receptors related to MHC class I molecules, they are KLRG1 ligands in tumor tissues of patients with ineffective cancer therapeutic agents. We found high expression of E-cadherin. Therefore, the present inventors, when administering the cancer therapeutic agent, when combined with a KLRG1 antagonist, the antibody-dependent cytotoxic activity of the cancer therapeutic agent is enhanced, even for patients who have been ineffective as a cancer therapeutic agent. The present inventors have found that a great antitumor effect is exhibited, and have completed the present invention. That is, the present invention relates to the following.

[1] A cancer therapeutic agent comprising an antibody having antibody-dependent cytotoxic activity against a cancer-specific membrane antigen expressed in epithelial cancer cells, the cancer therapeutic agent comprising (1) the cancer-specific membrane The above-mentioned cancer therapeutic agent, which is used for patients with epithelial cancer that is positive for an antigen and positive for a ligand for KLRG1, and is used in combination with (2) a KLRG1 antagonist.
[2] The cancer therapeutic agent according to [1], wherein the administration start timing of the cancer therapeutic agent is at the time of administration or after administration of the KLRG1 antagonist to the patient.
[3] The cancer therapeutic agent according to [1] or [2], wherein the cancer therapeutic agent further comprises the KLRG1 antagonist.
[4] The cancer therapeutic agent according to any one of [1] to [3], wherein the KLRG1 antagonist is an anti-KLRG1 antibody or a partial peptide thereof.
[5] The cancer therapeutic agent according to any one of [1] to [3], wherein the KLRG1 antagonist is soluble KLRG1 or a partial peptide thereof.
[6] The cancer therapeutic agent according to any one of [1] to [5], wherein the cancer-specific membrane antigen expressed in the epithelial cancer cells is HER2.
[7] The cancer therapeutic agent according to [6], wherein the antibody having antibody-dependent cytotoxic activity against a cancer-specific membrane antigen expressed in the epithelial cancer cell is trastuzumab.
[8] The cancer therapeutic agent according to any one of [1] to [5], wherein the cancer-specific membrane antigen expressed in the epithelial cancer cells is CEA.
[9] The cancer therapeutic agent according to any one of [1] to [8], wherein the ligand for KLRG1 is selected from the group consisting of E-cadherin, N-cadherin, and R-cadherin.
[10] The cancer therapeutic agent according to any one of [1] to [9], wherein the epithelial cancer is breast cancer.
[11] The cancer therapeutic agent according to any one of [1] to [9], wherein the epithelial cancer is gastric cancer.

[12] A pharmaceutical composition for use in a patient with epithelial cancer positive for a cancer-specific membrane antigen expressed in epithelial cancer cells and positive for a ligand for KLRG1, comprising the above-mentioned cancer-specific A pharmaceutical composition comprising an antibody having antibody-dependent cytotoxic activity against a membrane antigen and a KLRG1 antagonist.
[13] The pharmaceutical composition according to [12], wherein the pharmaceutical composition further comprises mononuclear cells isolated from the peripheral blood of the patient.
[14] The pharmaceutical composition according to [12] or [13], wherein the KLRG1 antagonist is an anti-KLRG1 antibody or a partial peptide thereof.
[15] The pharmaceutical composition according to [12] or [13], wherein the KLRG1 antagonist is soluble KLRG1 or a partial peptide thereof.
[16] The pharmaceutical composition according to any one of [12] to [15], wherein the cancer-specific membrane antigen expressed in the epithelial cancer cells is HER2.
[17] The pharmaceutical composition according to [16], wherein the antibody having antibody-dependent cytotoxic activity against the cancer-specific membrane antigen is trastuzumab.
[18] The pharmaceutical composition according to any one of [12] to [15], wherein the cancer-specific membrane antigen expressed in the epithelial cancer cells is CEA.
[19] The pharmaceutical composition according to any one of [12] to [18], wherein the ligand for KLRG1 is selected from the group consisting of E-cadherin, N-cadherin, and R-cadherin.
[20] The pharmaceutical composition according to any one of [12] to [19], wherein the epithelial cancer is breast cancer.
[21] The pharmaceutical composition according to any one of [12] to [19], wherein the epithelial cancer is gastric cancer.

[22] A cancer therapeutic agent comprising an antibody having an antibody-dependent cytotoxic activity against a cancer-specific membrane antigen expressed in epithelial cancer cells, wherein the cancer-specific membrane antigen is positive and against KLRG1 An agent that enhances the antibody-dependent cytotoxic activity of the cancer therapeutic agent used for a patient with epithelial cancer that is positive for a ligand and contains a KLRG1 antagonist.
[23] The agent according to [22], wherein the KLRG1 antagonist is an anti-KLRG1 antibody or a partial peptide thereof.
[24] The agent according to [22], wherein the KLRG1 antagonist is soluble KLRG1 or a partial peptide thereof.
[25] The drug according to any one of [22] to [24], wherein the cancer-specific membrane antigen expressed in the epithelial cancer cell is HER2.
[26] The drug according to [25], wherein the antibody having antibody-dependent cytotoxic activity against a cancer-specific membrane antigen expressed in the epithelial cancer cell is trastuzumab.
[27] The drug according to any one of [22] to [24], wherein the cancer-specific membrane antigen expressed in the epithelial cancer cell is CEA.
[28] The drug according to any one of [22] to [27], wherein the ligand for KLRG1 is selected from the group consisting of E-cadherin, N-cadherin, and R-cadherin.
[29] The drug according to any one of [22] to [28], wherein the epithelial cancer is breast cancer.
[30] The drug according to any one of [22] to [28], wherein the epithelial cancer is gastric cancer.

According to the present invention, even when an antibody against a cancer-specific membrane antigen expressed in epithelial cancer cells is administered, an effective anticancer effect can be obtained even in a patient that has not conventionally exhibited an anticancer effect. is there.

FIG. 1 shows the growth inhibitory effect of trastuzumab and anti-KLRG1 antibody on human breast cancer cell line HCC1569 inoculated in nude mice. None: No treatment group, Tra: Trastuzumab administration group, Ab: Hamster anti-KLRG1 antibody (clone name: 2F1) administration group, Tra + Ab: Trastuzumab and hamster anti-KLRG1 antibody (clone name: 2F1) administration group

  The cancer therapeutic agent of the present invention is a cancer therapeutic agent comprising an antibody having antibody-dependent cytotoxic activity against a cancer-specific membrane antigen expressed in epithelial cancer cells, wherein the cancer therapeutic agent comprises (1) It is used for patients with epithelial cancer that is positive for the cancer-specific membrane antigen and positive for a ligand for KLRG1, and (2) is used in combination with a KLRG1 antagonist.

  Examples of epithelial cancer in the present invention include breast cancer, gastric cancer, ovarian cancer, lung cancer, esophageal cancer, colon cancer, duodenal cancer, pancreatic cancer, head and neck cancer, gallbladder cancer, bile duct cancer, salivary gland cancer, and the like. Breast cancer and stomach cancer.

  Cancer specific membrane antigens expressed in epithelial cancer cells include HER2, carcinoembryonic antigen (CEA), mucin 1 (MUC-1), epithelial cell adhesion molecule (EpCAM), epidermal growth factor receptor (EGFR), cancer antigen 125 (CA125), kinase domain receptor (KDR), and the like. Preferably, HER2 and CEA.

  The antibody having antibody-dependent cytotoxic activity against a cancer-specific membrane antigen expressed in epithelial cancer cells is not particularly limited as long as it is an antibody against the above-mentioned cancer-specific membrane antigen and has antibody-dependent cytotoxic activity. Are preferably antibodies against HER2, CEA, MUC-1, EpCAM, EGFR, CA125, and KDR, more preferably anti-HER2 antibodies and anti-CEA antibodies. A preferred example of the anti-HER2 antibody is trastuzumab.

  Examples of ligands for KLRG1 include ligands selected from the group consisting of E-cadherin, N-cadherin, and R-cadherin.

  The KLRG1 antagonist is not particularly limited as long as it inhibits the binding of KLRG1 to a ligand for KLRG1 and blocks the inhibitory signal via KLRG1. Examples thereof include an anti-KLRG1 antibody having affinity for KLRG1 and an antagonist activity, or a partial peptide of anti-KLRG1 antibody. In addition, soluble KLRG1 having affinity for a ligand for KLRG1 or a partial peptide thereof is also used. From the viewpoint of affinity, preferably an anti-KLRG1 antibody or a partial peptide thereof, more preferably an anti-KLRG1 antibody is used.

  The antibody referred to in the present invention may be a monoclonal antibody that recognizes a specific epitope or a polyclonal antibody that recognizes a plurality of epitopes, but a monoclonal antibody is preferred from the viewpoint of specificity. In addition, antibodies may be derived from antibodies derived from animals such as mice, rats, rabbits, chimeric antibodies, humanized antibodies, human antibodies, etc., but from the viewpoint of safety, chimeric antibodies, humanized antibodies, human antibodies Are preferred, more preferred are humanized antibodies and human antibodies, and most preferred are human antibodies.

  The cancer therapeutic agent of the present invention is characterized by being used in combination with a KLRG1 antagonist. The administration start time of the cancer therapeutic agent is preferably during or after the administration of the KLRG1 antagonist, and the administration of the KLRG1 antagonist means simultaneous administration of the cancer therapeutic agent and the KLRG1 antagonist. The administration route of the cancer therapeutic agent and the KLRG1 antagonist is not particularly limited, but is preferably the same from the viewpoint of burden on the patient.

  The dose of the therapeutic agent for cancer in the present invention is not particularly limited as long as it exhibits a therapeutic effect, but the dose varies depending on the antibody or antibody fragment and also varies depending on the form. From the viewpoint of side effects and safety, the preferred dose of the cancer therapeutic agent is in the range of 0.1 mg / kg to 40 mg / kg as the amount of the antibody as the active ingredient. The dosage of the KLRG1 antagonist is not particularly limited because it varies depending on the properties of the antagonist, but it must be an amount that enhances the antibody-dependent cytotoxic activity of the cancer therapeutic agent.

  The present invention further relates to a pharmaceutical composition for use in a patient with epithelial cancer that is positive for a cancer-specific membrane antigen expressed in epithelial cancer cells and positive for a ligand for KLRG1. The present invention relates to a pharmaceutical composition comprising an antibody having an antibody-dependent cytotoxic activity against a specific membrane antigen and a KLRG1 antagonist. A pharmaceutical composition comprising an antibody having antibody-dependent cytotoxic activity against a cancer-specific membrane antigen and a KLRG1 antagonist is particularly in the form and properties as long as it contains an anti-cancer-specific membrane antigen antibody and a KLRG1 antagonist. Although it is not limited, a state where it can be easily administered is preferable, and a liquid state is most preferable. The pharmaceutical composition may comprise mononuclear cells isolated from the patient's peripheral blood. Mononuclear cells are preferably prepared from a patient prior to use using an extracorporeal blood component separator by centrifugation and mixed with an anti-cancer specific membrane antigen antibody and a KLRG1 antagonist.

  The pharmaceutical composition comprising an antibody having antibody-dependent cytotoxic activity against a cancer-specific membrane antigen as used in the present invention and a KLRG1 antagonist may be a mixture of the antibody and KLRG1 antagonist in advance. In addition, it may be mixed at the time of administration.

  The present invention is further a cancer therapeutic agent comprising an antibody having antibody-dependent cytotoxic activity against a cancer-specific membrane antigen expressed in epithelial cancer cells, wherein the cancer-specific membrane antigen is positive, and The present invention relates to a drug for enhancing the antibody-dependent cytotoxic activity of the cancer therapeutic agent used for a patient with epithelial cancer positive for a ligand for KLRG1, and comprising the KLRG1 antagonist. Examples of the KLRG1 antagonist in the above-mentioned drug include those described above in the present specification (anti-KLRG1 antibody having affinity for KLRG1, or partial peptide of anti-KLRG1 antibody having antagonist activity, and soluble KLRG1 having affinity for a ligand for KLRG1. Or a partial peptide thereof).

  The following examples further illustrate the present invention in detail but are not to be construed to limit the scope thereof.

[Example 1]
(A) Method (1) Mice Six-week-old female nude mice (BALB / cAJcl-nu / nu) were purchased from CLEA Japan. All animals were maintained and handled according to institutional guidelines based on certified protocols.

(2) Administration of trastuzumab and anti-KLRG1 antibody
5.0 × 10 ⁶ HER2-positive E-cadherin-positive human breast cancer cell line HCC1569 was suspended in 0.2 ml of PBS and inoculated subcutaneously into nude mice. The tumor-bearing mice were divided into the following 4 groups. 1) No treatment group (control group), 2) Trastuzumab administration group, 3) Hamster anti-KLRG1 antibody (product name: Functional Grade Purified anti-mouse KLRG1 / MAFA, manufacturer: eBioscience, clone name: 2F1, antibody against mouse KLRG1 However, it also crosses with human KLRG1 (hereinafter referred to as an anti-KLRG1 antibody) administration group, 4) a group to which both trastuzumab and anti-KLRG1 antibody are administered. Trastuzumab was administered intraperitoneally at 5 μg per gram of mouse body weight, and anti-KLRG1 antibody was administered intraperitoneally at 10 μg per mouse.
The group that received both trastuzumab and anti-KLRG1 antibody received trastuzumab approximately 30 minutes after administration of anti-KLRG1 antibody.
Administration of trastuzumab and anti-KLRG1 antibody was started 4 weeks after inoculation with HCC1569 and continued once a week for 10 weeks.

(3) Measurement of tumor volume The tumor volume was calculated according to the following equation by measuring the length, width and thickness of the tumor using a caliper once a week.
Tumor volume (mm ³ ) = (length: mm) × (width: mm) × (thickness: mm)

(B) Results
Tumor volume data at 4 and 9 weeks after inoculation with HCC1569 are shown in FIG. In the 9-week data after inoculation with HCC1569, the tumor volume was highly increased in the untreated group, the trastuzumab-administered group, and the group administered with the anti-KLRG1 antibody, compared with 4 weeks. In the group receiving both trastuzumab and anti-KLRG1 antibody, the increase in tumor volume was mild (FIG. 1).

  According to the cancer therapeutic agent of the present invention, an antitumor effect can be exerted even on a patient for whom a conventional cancer therapeutic agent containing an antibody against a cancer-specific membrane antigen is ineffective, and the conventional cancer therapeutic agent The effective rate can be greatly increased.

Claims (30)

A cancer therapeutic agent comprising an antibody having antibody-dependent cytotoxic activity against a cancer-specific membrane antigen expressed in epithelial cancer cells, wherein the cancer therapeutic agent is (1) positive for the cancer-specific membrane antigen The cancer therapeutic agent, which is used for a patient with epithelial cancer that is positive for a ligand for KLRG1, and is used in combination with (2) a KLRG1 antagonist. The cancer therapeutic agent according to claim 1, wherein the administration start time of the cancer therapeutic agent is at the time of administration or after administration of the KLRG1 antagonist to the patient. The cancer therapeutic agent according to claim 1 or 2, wherein the cancer therapeutic agent further comprises the KLRG1 antagonist. The cancer therapeutic agent according to any one of claims 1 to 3, wherein the KLRG1 antagonist is an anti-KLRG1 antibody or a partial peptide thereof. The cancer therapeutic agent according to any one of claims 1 to 3, wherein the KLRG1 antagonist is soluble KLRG1 or a partial peptide thereof. The cancer therapeutic agent according to any one of claims 1 to 5, wherein the cancer-specific membrane antigen expressed in the epithelial cancer cells is HER2. The cancer therapeutic agent according to claim 6, wherein the antibody having antibody-dependent cytotoxic activity against a cancer-specific membrane antigen expressed in the epithelial cancer cell is trastuzumab. The cancer therapeutic agent according to any one of claims 1 to 5, wherein the cancer-specific membrane antigen expressed in the epithelial cancer cells is CEA. The cancer therapeutic agent according to any one of claims 1 to 8, wherein the ligand for KLRG1 is selected from the group consisting of E-cadherin, N-cadherin, and R-cadherin. The cancer therapeutic agent according to any one of claims 1 to 9, wherein the epithelial cancer is breast cancer. The cancer therapeutic agent according to any one of claims 1 to 9, wherein the epithelial cancer is gastric cancer. A pharmaceutical composition for use in a patient with epithelial cancer that is positive for a cancer-specific membrane antigen expressed in epithelial cancer cells and positive for a ligand for KLRG1, comprising the above-mentioned cancer-specific membrane antigen A pharmaceutical composition comprising an antibody having antibody-dependent cytotoxic activity and a KLRG1 antagonist. 13. The pharmaceutical composition of claim 12, wherein the pharmaceutical composition further comprises mononuclear cells isolated from the patient's peripheral blood. The pharmaceutical composition according to claim 12 or 13, wherein the KLRG1 antagonist is an anti-KLRG1 antibody or a partial peptide thereof. The pharmaceutical composition according to claim 12 or 13, wherein the KLRG1 antagonist is soluble KLRG1 or a partial peptide thereof. The pharmaceutical composition according to any one of claims 12 to 15, wherein the cancer-specific membrane antigen expressed in the epithelial cancer cells is HER2. The pharmaceutical composition according to claim 16, wherein the antibody having antibody-dependent cytotoxic activity against the cancer-specific membrane antigen is trastuzumab. The pharmaceutical composition according to any one of claims 12 to 15, wherein the cancer-specific membrane antigen expressed in the epithelial cancer cells is CEA. The pharmaceutical composition according to any one of claims 12 to 18, wherein the ligand for KLRG1 is selected from the group consisting of E-cadherin, N-cadherin, and R-cadherin. The pharmaceutical composition according to any one of claims 12 to 19, wherein the epithelial cancer is breast cancer. The pharmaceutical composition according to any one of claims 12 to 19, wherein the epithelial cancer is gastric cancer. A cancer therapeutic agent comprising an antibody having an antibody-dependent cytotoxic activity against a cancer-specific membrane antigen expressed in epithelial cancer cells, wherein the cancer-specific membrane antigen is positive and a ligand for KLRG1 is positive A drug that enhances the antibody-dependent cytotoxic activity of the cancer therapeutic agent used for patients with epithelial cancer and contains a KLRG1 antagonist. The drug according to claim 22, wherein the KLRG1 antagonist is an anti-KLRG1 antibody or a partial peptide thereof. 23. The agent according to claim 22, wherein the KLRG1 antagonist is soluble KLRG1 or a partial peptide thereof. The drug according to any one of claims 22 to 24, wherein the cancer-specific membrane antigen expressed in the epithelial cancer cell is HER2. The drug according to claim 25, wherein the antibody having antibody-dependent cytotoxic activity against a cancer-specific membrane antigen expressed in the epithelial cancer cell is trastuzumab. The drug according to any one of claims 22 to 24, wherein the cancer-specific membrane antigen expressed in the epithelial cancer cells is CEA. 28. The agent according to any one of claims 22 to 27, wherein the ligand for KLRG1 is selected from the group consisting of E-cadherin, N-cadherin and R-cadherin. 29. The agent according to any one of claims 22 to 28, wherein the epithelial cancer is breast cancer. 29. The drug according to any one of claims 22 to 28, wherein the epithelial cancer is gastric cancer.

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