A combination of an antibody and a pharmaceutical composition.

Abstract

The present invention relates to a conjugate of an antibody or a fragment thereof linked to an immune activator, wherein the antibody or its fragment possesses immunological reactivity with a caprin-1 protein, and to a pharmaceutical composition comprising the conjugate as an active ingredient for the treatment and / or prevention of cancer that is superior in antitumor activity to conventional antibodies or to conjugates of an antibody and an immune activator.

Description

"CONJUGATE OF AN ANTIBODY AND PHARMACEUTICAL COMPOSITION" Field of the Invention

[001] The present invention relates to a conjugate of an antibody against a CAPRIN-1 protein and an immune activator, and to its medical use as a therapeutic and / or preventive agent for cancer, and the like. Background of the Invention

[002] Several antibody drugs targeting specific antigenic proteins in cancer cells are applied as therapeutic drugs for cancers with fewer adverse reactions to cancer treatment due to their cancer specificity. For example, cytoplasmic activation and proliferation-associated protein 1 (CAPRIN-1) are expressed on the cell membrane surface of a large number of solid cancers, and antibodies against this CAPRIN1 protein are believed to be promising for medical use in the treatment and / or prevention of cancers (Patent Literature 1).

[003] In recent years, studies have been conducted to enhance the pharmacological effects of antibody drugs. In particular, antibody-drug conjugates (ADCs) in which an antibody is conjugated with a drug that has the intense ability to directly kill actively developed cells (Non-Patent Literature 1 and 2). As examples of ADCs, Kadcyla(R)(trastuzumab emtansine), which comprises an existing trastuzumab drug antibody linked to an emtansine drug (DM1), which exhibits cell-killing activity, and Adcetris(R)(brentuximab vedotin), which comprises an anti-CD30 monoclonal antibody linked to monomethyl auristatin E (MMAE), are used in the treatment of some types of cancer. These ADCs have been found to prolong survival rates compared to conventional treatment methods and are useful in relation to existing methods for cancer treatment (Literature of Petition 870260047669, dated 05 / 19 / 2026, p. 14 / 272 2 / 116 Non-Patents 3 and 4).

[004] In other cases, studies have also been carried out in an attempt to intensify pharmacological effects through the conjugation of immune activators to antibody drugs against cancers. For example, it has been found that a conjugate of an existing antibody of trastuzumab or cetuximab with resiquimod, one of the immune activators, or conjugates of an antibody drug of rituximab against CD20 as a target antigen with various immune activators has an effect of intensifying the pharmacological effect of the antibody in animal models (Patent Literature 2 and 3).

[005] As described above, attempts have been made to enhance the pharmacological effects of antibody drugs against cancers by conjugating various factors to various antibodies. However, antitumor effects strong enough to completely regress various types of cancer have not yet been obtained. Furthermore, effects on preventing cancer recurrence or metastasis, and similar effects, have not been found. Patent Literature

[006] Patent Literature 1: WO 2010 / 016526; - Patent Literature 2: WO 2014 / 012479; and - Patent Literature: US Patent 8,951,528 Non-Patented Literature

[007] Non-Patent Literature 1: Lancet Oncol 2016; 17: e254-62; - Non-Patent Literature 2: Pharm Res. 2015 Nov; 32 (11): 3.526-40; - Non-Patent Literature 3: New England Journal of Medicine 367; 19 (8), 2012, p. 1783 - 1791; and - Non-Patent Literature 4: MAbs 2012; 4 (4): 458-65 Brief Description of the Invention

[008] An object of the present invention is to provide a solution for Petition 870260047669, dated 05 / 19 / 2026, page 15 / 272 3 / 116 to enhance the antitumor effect of an antibody or a fragment thereof against a CAPRIN-1 protein expressed on the cell membrane surface of cancer cells.

[009] The present Applicant has conducted diligent studies and consequently completed the present invention by discovering that: a conjugate of an antibody or a fragment thereof against a CAPRIN-1 protein and an immune activator exerts a much more intense antitumor effect than that of the antibody against the CAPRIN-1 protein or the fragment thereof used alone; and the effect of intensifying the antitumor effect by conjugating the antibody against the CAPRIN-1 protein or the fragment thereof to the immune activator is much superior to the effect of intensifying the antitumor effect by conjugating an existing antibody drug for cancer to the immune activator.

[010] Specifically, the present invention has the following characteristics from (1) to (14): (1) A conjugate of an antibody or a fragment thereof linked to an immune activator, wherein the antibody or fragment thereof has immunological reactivity with a CAPRIN-1 protein that has an amino acid sequence represented by any of the even-numbered SEQ ID NOs between SEQ ID NOs: 2 to 30 or an amino acid sequence that has 80% or more sequence identity with the amino acid sequence; (2) The conjugate, according to (1), wherein the antibody or its fragment has immunological reactivity with a partial polypeptide of the CAPRIN-1 protein, wherein the partial polypeptide has an amino acid sequence represented by any of the SEQ ID NOs: 31 to 35 and 296 to 299, 308 and 309 or an amino acid sequence that has 80% or more sequence identity with the amino acid sequence; Petition 870260047669, dated 05 / 19 / 2026, page 16 / 272 4 / 116 (3) The conjugate, according to (1) or (2), wherein the antibody is a monoclonal antibody or a polyclonal antibody; (4) The conjugate, according to any one of (1) to (3), wherein the antibody or fragment thereof is any one of the following from (A) to (M): (A) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 36, 37 and 38 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 40, 41 and 42 (CDR1, CDR2 and CD3, respectively) and possessing immunological reactivity with the CAPRIN-1 protein; (B) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 44, 45 and 46 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 48, 49 and 50 (CDR1, CDR2 and CDR3, respectively) and possessing immunological reactivity with the CAPRIN-1 protein; (C) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 52, 53 and 54 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 56, 57 and 58 (CDR1, CDR2 and CDR3, respectively) and possessing immunological reactivity with the CAPRIN-1 protein; (D) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 60, 61 and 62 (CDR1, Petition 870260047669, dated 05 / 19 / 2026, page 17 / 272 5 / 116 CDR2 and CDR3, respectively) and a variable region of the light chain that comprises the complementarity-determining regions of SEQ ID NOs: 64, 65 and 66 (CDR1, CDR2 and CDR3, respectively) and has immunological reactivity with the CAPRIN-1 protein; (E) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 170, 171 and 172 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 173, 174 and 175 (CDR1, CDR2 and CDR3, respectively) and possessing immunological reactivity with the CAPRIN-1 protein; (F) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 176, 177 and 178 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 179, 180 and 181 (CDR1, CDR2 and CDR3, respectively) and possessing immunological reactivity with the CAPRIN-1 protein; (G) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 182, 183 and 184 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 185, 186 and 187 (CDR1, CDR2 and CDR3, respectively) and possessing immunological reactivity with the CAPRIN-1 protein; (H) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 188, 189 and 190 (CDR1, Petition 870260047669, dated 05 / 19 / 2026, page 18 / 272 6 / 116 CDR2 and CDR3, respectively) and a variable region of the light chain that comprises the complementarity-determining regions of SEQ ID NOs: 191, 192 and 193 (CDR1, CDR2 and CDR3, respectively) and has immunological reactivity with the CAPRIN-1 protein; (I) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 146, 147 and 148 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 149, 150 and 223 (CDR1, CDR2 and CDR3, respectively) and possessing immunological reactivity with the CAPRIN-1 protein; (J) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 272, 273 and 274 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 275, 276 and 277 (CDR1, CDR2 and CDR3, respectively) and possessing immunological reactivity with the CAPRIN-1 protein; (K) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 290, 291 and 292 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 293, 294 and 295 (CDR1, CDR2 and CDR3, respectively) and possessing immunological reactivity with the CAPRIN-1 protein; (L) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 300, 301 and 302 (CDR1, Petition 870260047669, dated 05 / 19 / 2026, page 19 / 272 7 / 116 CDR2 and CDR3, respectively) and a variable region of the light chain that comprises the complementarity-determining regions of SEQ ID NOs: 304, 305 and 306 (CDR1, CDR2 and CDR3, respectively) and has immunological reactivity with the CAPRIN-1 protein; (M) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 134, 135 and 136 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 137, 138 and 139 (CDR1, CDR2 and CDR3, respectively) and possessing immunological reactivity with the CAPRIN-1 protein; (5) The conjugate, according to any one of (1) to (4), wherein the antibody or fragment thereof is any one of the following from (a) to (b): (a) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 39 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 43, (b) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 47 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 51, (c) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 55 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 59, (d) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 63 and a variable region of the light chain comprising Petition 870260047669, dated 05 / 19 / 2026, p. 20 / 272 8 / 116 comprises the amino acid sequence of SEQ ID NO: 67, (e) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 68 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 69, (f) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 70 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 71, (g) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 72 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 73, (h) an antibody or a fragment thereof,comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 74 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 75, (i) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 76 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 77, (j) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 78 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 79, (k) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 80 and a variable region of the light chain that, Petition 870260047669, dated 05 / 19 / 2026, page 21 / 272 9 / 116 comprises the amino acid sequence of SEQ ID NO: 81, (l) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 82 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 83; (m) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 84 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 85; (n) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 86 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 87, (o) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 88 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 89, (p) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 90 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 91, (q) an antibody or a fragment thereof,comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 92 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 93, (r) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 94 and a variable region of the light chain that, Petition 870260047669, dated 05 / 19 / 2026, page 22 / 272 10 / 116 comprises the amino acid sequence of SEQ ID NO: 95; (s) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 96 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 97, (t) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 98 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 99, (u) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 100 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 101, (v) an antibody or a fragment thereof,comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 102 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 103, (w) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 104 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 105, (x) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 106 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 107; (y) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 108 and a variable region of the light chain that Petition 870260047669, dated 05 / 19 / 2026, page 23 / 272 11 / 116 comprises the amino acid sequence of SEQ ID NO: 109, (z) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 110 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 111, (aa) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 112 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 113, (ab) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 114 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 115, (ac) an antibody or a fragment thereof,comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 116 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 117, (ad) an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 118 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 119, (ae) an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 120 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 121, (af) an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 122 and a variable region of the light chain comprising, Petition 870260047669, dated 05 / 19 / 2026, page 24 / 272 12 / 116 comprises the amino acid sequence of SEQ ID NO: 123, (ag) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NOs: 124 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 125, (ah) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 126 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 127, (ai) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NOs: 128 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 129, (aj) an antibody or a fragment thereof,comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 130 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 131, (ak) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 132 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 133 and (al) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 303 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 307; (6) The conjugate, according to any one of (1) to (5), wherein the antibody is a human antibody, a humanized antibody, a chimeric antibody or a single-chain antibody; Petition 870260047669, dated 05 / 19 / 2026, page 25 / 272 13 / 116 (7) The conjugate, according to any one of (1) to (6), wherein the immune activator is a ligand or an agonist that binds to Toll-like receptor (TLR), NOD-like receptor (NLR), RIG-like receptor, or C-type lectin receptor (CLR); (8) The conjugate, according to (7), in which the Toll-like receptor (TLR) is TLR2, TLR3, TLR4, TLR5, TLR7, TLR8, TLR9 or TLR10; (9) The conjugate, according to (7) or (8), in which the ligand or agonist that binds to the Toll-like receptor (TLR), or a derivative thereof, is any one of the following from (i) to (vii): (i) a ligand or agonist that binds to TLR2 selected from the group consisting of peptidoglycan, lipoprotein, lipopolysaccharide, and zymosan, (ii) a ligand or agonist that binds to TLR3 selected from the group consisting of poly(I:C) and poly(A:U), (iii) a ligand or agonist that binds to TLR4 selected from the group consisting of lipopolysaccharide (LPS), HSP60, RS09, and MPLA, (iv) a ligand or agonist that binds to TLR5 selected from the group consisting of flagellin and FLA, (v) a ligand or agonist that binds to TLR7 or TLR8 selected from the group consisting of an imidazoquinoline compound and single-stranded RNA, (vi) a ligand or agonist that binds to TLR9 selected from the group consisting of bacterial DNA, unmethylated CpG DNA, hemozoin, ODN1585, ODN1668 and ODN1826, and (vii) a TLR10-binding ligand or agonist selected from the group consisting of profilin and a uropathogenic bacterium; (10) The conjugate, according to any one of (1) to (9), in which the antibody or a fragment thereof is linked to the immune activator by means of Petition 870260047669, dated 05 / 19 / 2026, page 26 / 272 14 / 116 a ligand; (11) A pharmaceutical composition for the treatment and / or prevention of cancer, comprising the conjugate according to any one of (1) to (10) as an active ingredient; (12) The pharmaceutical composition, according to (11), in which the cancer is a cancer that expresses the CAPRIN-1 protein on the surface of the cell membrane; (13) A pharmaceutical composition, according to (11) or (12), wherein cancer is a cancer selected from the group consisting of breast cancer, kidney cancer, pancreatic cancer, colorectal cancer, lung cancer, brain tumor, stomach cancer, uterine cancer, ovarian cancer, prostate cancer, bladder cancer, esophageal cancer, leukemia, lymphoma, liver cancer, gallbladder cancer, sarcoma, mast cell tumor, melanoma, adrenal cortex cancer, Ewing's tumor, Hodgkin's lymphoma, mesothelioma, multiple myeloma, testicular cancer, thyroid cancer and head and neck cancer; and (14) A method for the treatment and / or prevention of a cancer, comprising administering the conjugate, according to any of (1) to (10), or the pharmaceutical composition, according to any of (11) to (13), to an individual.

[011] The conjugate, according to the present invention, not only exerts a much more intense antitumor effect than that of an antibody against a CAPRIN-1 protein used alone, but is superior in antitumor effect to a known conjugate of an antibody drug for cancer and an immune activator. Furthermore, the effect of intensifying the antitumor effect through the conjugate, according to the present invention, is superior to the effect of intensifying the antitumor effect through the conjugation of an existing antibody drug for cancer with the immune activator. By Petition 870260047669, dated 05 / 19 / 2026, page 27 / 272 15 / 116 consequently, the conjugate, according to the present invention, is effective for the treatment or prevention of cancer. Description of Achievements

[012] The conjugate of an antibody or a fragment thereof against a CAPRIN-1 protein (hereinafter referred to as an anti-CAPRIN-1 antibody) and an immune activator used in the present invention can be evaluated for its antitumor activity, as mentioned below, by examining in vivo the inhibition of tumor growth in a cancer-bearing animal.

[013] In the present invention, the term conjugate refers to an antibody linked to an immune activator by means of a covalent bond. The link between the antibody and the immune activator can be achieved through a ligand.

[014] The anti-CAPRIN-1 antibody that is a constituent of the conjugate, according to the present invention, can be a monoclonal antibody or a polyclonal antibody and, preferably, is a monoclonal antibody. The anti-CAPRIN-1 antibody can be any type of antibody provided that the conjugate of the present invention can exert antitumor activity. The antibody is a recombinant antibody, a human antibody, a humanized antibody, a chimeric antibody or a non-human animal antibody.

[015] The immune activator that is a constituent of the conjugate, according to the present invention, can be any immune activator factor and, preferably, is a ligand or an agonist, or a derivative thereof, that binds to the Toll-like receptor (TLR), NOD-like receptor (NLR), RIG-like receptor or C-type lectin receptor (CLR), most preferably a ligand or an agonist, or a derivative thereof, that binds to the Toll-like receptor (TLR).

[016] The individual to be treated and / or prevented from cancer according to the present invention is a mammal such as a human being, a Petition 870260047669, dated 05 / 19 / 2026, page 28 / 272 16 / 116 pet, livestock or a sport animal, and an individual preferably, is a human being.

[017] Hereafter, the anti-CAPRIN-1 antibody, the immune activator, the conjugate of the anti-CAPRIN-1 antibody and the immune activator, the pharmaceutical composition comprising the conjugate and the method for treating and / or preventing cancer using the conjugate, according to the present invention, will be described. <Anticorpo anti-CAPRIN-1>

[018] Among the CAPRIN-1 proteins that have an amino acid sequence represented by any of the even-numbered SEQ ID NOs between SEQ ID NOs: 2 to 30 and that have immunological reactivity with the anti-CAPRIN-1 antibody used in the present invention, the amino acid sequences represented by SEQ ID NOs: 6, 8, 10, 12 and 14 are the amino acid sequences of canine CAPRIN-1 proteins; the amino acid sequence represented by SEQ ID NOs: 2 and 4 are the amino acid sequences of human CAPRIN-1 proteins; the amino acid sequence represented by SEQ ID NO: 16 is the amino acid sequence of a bovine CAPRIN-1 protein; the amino acid sequence represented by SEQ ID NO: 18 is the amino acid sequence of an equine CAPRIN-1 protein; The amino acid sequences represented by the SEQ ID NOs: 20 to 28 are the amino acid sequences of mouse CAPRIN-1 proteins;The amino acid sequence represented by SEQ ID NO: 30 is the amino acid sequence of a chicken CAPRIN-1 protein.

[019] The anti-CAPRIN-1 antibody used in the present invention may possess immunological reactivity with a variant of the CAPRIN1 protein having 80% or more, preferably 90% or more, more preferably 95% or more, and even more preferably 99% or more sequence identity for the amino acid sequence represented by any of the Petition 870260047669, dated 05 / 19 / 2026, p. 29 / 272 17 / 116 SEQ ID NOs of even numbers between SEQ ID NOs: from 2 to 30. In this context, the term percentage (%) of sequence identity means a percentage (%) of the number of identical amino acids (or bases) to the total number of amino acids (or bases) when two sequences are aligned, so that the maximum degree of similarity can be achieved with or without the introduction of a gap.

[020] In the present invention, the anti-CAPRIN-1 antibody used for the preparation of the conjugate means an antibody or a fragment thereof that has immunological reactivity with a CAPRIN-1 protein in its entire length or a fragment thereof. In this context, the term immunological reactivity means the property of the antibody that binds to the CAPRIN-1 protein or to a partial polypeptide thereof in vivo.

[021] The anti-CAPRIN-1 antibody used in the present invention can be a monoclonal antibody or a polyclonal antibody.

[022] The polyclonal antibody that has immunological reactivity with the CAPRIN-1 protein in its entire length or a fragment thereof (anti-CAPRIN-1 polyclonal antibody) can be obtained, for example, by immunizing a mouse, a human antibody-producing mouse, a rat, a rabbit, a chicken or similar animals with a naturally occurring CAPRIN-1 protein, or a fusion protein thereof with GST or similar animals, or a partial peptide thereof, and obtaining the serum and applying the serum obtained to precipitation with ammonium sulfate, protein A, protein G, a DEAE ion exchange column, an affinity column linked to a CAPRIN-1 protein or a partial peptide, or similar.

[023] Regarding the CAPRIN-1 protein in its entirety or the fragment thereof to be used in immunization, the nucleotide sequences and amino acid sequences of CAPRIN-1 and its homologs are available, for example, by accessing GenBank (NCBI, USA) and using Petition 870260047669, dated 05 / 19 / 2026, p. 30 / 272 18 / 116 an algorithm such as BLAST or FASTA (Karlin and Altschul, Proc. Natl. Acad. Sci. USA, 90: 5.873-5.877, 1993; and Altschul et al, Nucleic Acids Res. 25: 3.389-3.402, 1997). Furthermore, a method for preparing the CAPRIN-1 protein is available with reference to publication WO 2014 / 012479, or it can be performed using, for example, cells expressing the CAPRIN-1 protein.

[024] The monoclonal antibody that has immunological reactivity with the CAPRIN-1 protein in its full length or a fragment thereof (anti-CAPRIN-1 monoclonal antibody) can be obtained, for example, by: administering SK-BR-3 (breast cancer cells expressing CAPRIN-1) or the CAPRIN-1 protein in its full length or a fragment thereof, or similar to a mouse for immunization; fusing spleen cells separated from mice with myeloma cells; and selecting a clone producing anti-CAPRIN-1 monoclonal antibodies from among the fusion cells obtained (hybridomas). The antibody produced from the hybridoma selected in this way can be prepared in the same way as the polyclonal antibody purification method mentioned above.

[025] The antibody used in the present invention includes human antibodies, humanized antibodies, chimeric antibodies and non-human animal antibodies.

[026] Human antibody can be obtained through: sensitization of human lymphocytes infected with EB virus, with the protein, cells that express the proteins or their lysates; fusion of sensitized lymphocytes with cells derived from human myeloma, such as U266 cells; and obtaining an antibody that has immunological reactivity with the CAPRIN-1 protein in its full length or a fragment thereof from the fusion cells obtained.

[027] A humanized antibody, also called a remodeled human antibody, is a manipulated antibody. A humanized antibody is Petition 870260047669, dated 05 / 19 / 2026, page 31 / 272 19 / 116 constructed by grafting complementarity-determining regions of an antibody derived from an immunized animal onto complementarity-determining regions of a human antibody. A genetic engineering technique commonly used to construct humanized antibodies is also well known. Specifically, DNA sequences designed to link complementarity-determining regions, for example, of a mouse or rabbit antibody, to the structure regions of a human antibody are synthesized by PCR from various prepared oligonucleotides that have overlapping terminal portions. The resulting DNAs are ligated with DNAs encoding the constant regions of human antibodies. The resulting ligation products are incorporated into expression vectors which are then transferred to hosts for antibody production to obtain the antibody of interest.(See European Patent Application Publication EP 239,400 and International Publication WO 1996 / 02576). The structural regions of a human antibody connected via complementarity-determining regions are selected so that the complementarity-determining regions form a binding site favorable to the antigen. If necessary, an amino acid in the variable regions of the antibody can be substituted so that the complementarity-determining regions of a remodeled human antibody form a suitable antigen-binding site (Sato K. et al, Cancer Research 1993, 53: 851-856). Additionally, these structural regions can be replaced by structural regions derived from various human antibodies (see publication WO 1999 / 51743).

[028] Antibodies are typically heteromultimeric glycoproteins, each comprising at least two heavy chains and two light chains. Antibodies are composed of two identical light chains and two identical heavy chains. Each heavy chain has Petition 870260047669, dated 05 / 19 / 2026, page 32 / 272 20 / 116 a variable region of the heavy chain at one end, followed by a series of constant regions. Each light chain has a variable region of the light chain at one end, followed by a series of constant regions. The variable regions contain specific variable regions called complementarity-determining regions (CDRs) and confer binding specificity to the antibody. The relatively conserved portions in the variable regions are called structure regions (FRs). Each of the complete heavy chain and light chain variable regions contains four FRs connected by three CDRs (from CDR1 to CDR3).

[029] Human-derived constant and variable region sequences of heavy and light chains are available, for example, from NCBI (USA; GenBank, UniGene and similar). For example, the following sequences can be referenced: accession number J00228 for a constant region of the human IgG1 heavy chain; accession number J00230 for a constant region of the human IgG2 heavy chain; accessions V00557, X64135, X64133 and similar, for a constant κ region of the human light chain; and accessions X64132, X64134 and similar, for a constant λ region of the human light chain.

[030] A chimeric antibody is an antibody prepared from a combination of sequences derived from different animals and, for example, may be an antibody composed of variable heavy chain and light chain regions from a mouse antibody and constant regions of variable heavy chain and light chain regions from a human antibody. The chimeric antibody may be prepared using a method known in the art and is obtained, for example, by: ligating the DNAs encoding the V regions of the antibody to the DNAs encoding the C regions of the human antibody; incorporating the resulting ligation products into expression vectors; and transferring the vectors to the hosts for antibody production. Petition 870260047669, dated 05 / 19 / 2026, page 33 / 272 21 / 116

[031] Non-human animal antibody obtained by immunizing an animal with a sensitizing antigen, according to a method known in the state of the art and, as a general method, by intraperitoneal, intracutaneous or subcutaneous injection of a sensitizing antigen into an animal such as a mouse. For the injection of the sensitizing antigen, the antigen is mixed in an appropriate quantity with various adjuvants including CFA (complete Freund's adjuvant), and the mixture is administered to the animal a plurality of times. The animal is immunized and then checked to find that it contains anti-CAPRIN-1 antibodies in the serum. The serum can be obtained and applied, as mentioned above, for precipitation with ammonium sulfate, protein A, protein G, a DEAE ion exchange column, an affinity column linked to a CAPRIN-1 protein or a partial peptide, or similar, to obtain the non-human animal antibody.In the case of obtaining a monoclonal antibody from a non-human animal, immunocytes can be collected from an immunized animal and subjected to cell fusion with myeloma cells to obtain the monoclonal antibody. Cell fusion between immunocytes and myeloma cells can be performed according to a method known in the state of the art (see Kohler, G. and Milstein, C. Methods Enzymol. (1981) 73, 3-46).

[032] The antibody used in the present invention can also be obtained as a recombinant antibody produced using a genetic engineering technique by cloning antibody genes from a hybridoma; incorporating antibody genes into suitable vectors; and transferring vectors to hosts (see Carl, AK Borrebaeck, James, W. Larrick, Therapeutic Monoclonal Antibodies, published in the UK by Macmillan Publishers LTD, 1990).

[033] The anti-CAPRIN-1 antibody used to obtain the conjugate of the present invention may be an antibody in which an amino acid Petition 870260047669, dated 05 / 19 / 2026, p. 34 / 272 22 / 116 in a variable region (e.g., FR) or in a constant region is replaced by another amino acid. Amino acid substitution is the replacement of one or more, for example, less than 15, less than 10, 8 or less, 6 or less, 5 or less, 4 or less, 3 or less, or 2 or less of amino acids, preferably from 1 to 9 amino acids. The substituted antibody must be an antibody that possesses the property of specifically binding to the antigen and of equivalent or superior antigen-binding affinity to that of the corresponding unsubstituted antibody and does not cause any rejection when applied to humans.

[034] It is expected that the anti-CAPRIN-1 antibody used in the present invention will have a stronger antitumor effect, the greater binding affinity for the CAPRIN-1 protein on the surface of cancer cells that the antibody possesses. Its association constant (affinity constant) Ka (kon / koff) is preferably at least 107 M-1, at least 108M-1, at least 5 x 108M-1, at least 109M-1, at least 5 x 109M-1, at least 1010M-1, at least 5 x 1010M-1, at least 1011M-1, at least 5 x 1011M-1, at least 1012M-1, or at least 1013M-1.

[035] The binding activity of the anti-CAPRIN-1 antibody used in the present invention against effector cells can be enhanced by substituting one, two, or several amino acids in the constant region of the antibody heavy chain or by removing the fucose added to N-acetylglucosamine in a sugar chain linked to the N-glycoside attached to the constant region of the heavy chain. Such an antibody may possess the amino acid substitution alone or may be in a composition comprising a fucosylated antibody.

[036] The antibody in which one, two or several amino acids in the constant region of the heavy chain are substituted can be prepared with reference, for example, to publications WO 2004 / 063351, WO 2011 / 120135, US patent 8,388,955, WO 2011 / 005481, US patent 6,737,056 and / or WO Petition 870260047669, dated 05 / 19 / 2026, page 35 / 272 23 / 116 2005 / 063351.

[037] The fucose-free antibody added to N-acetylglucosamine on a sugar chain linked to the N-glycoside in the constant region of the heavy chain has been removed, or the antibody-producing cells can be prepared with reference to US patent 6,602,684, European patent 1,914,244, and / or US patent 7,579,170. A composition of the fucose-free antibody added to N-acetylglucosamine on a sugar chain linked to the N-glycoside connected to the constant region of the heavy chain, and the antibody possessing fucose, or the cells producing the composition can be prepared with reference, for example, to US patent 8,642,292.

[038] Methods for the preparation and purification of the anti-CAPRIN-1 polyclonal antibody, the anti-CAPRIN-1 monoclonal antibody and the antibody used in the present invention, and a method for the preparation of the CAPRIN-1 protein or its partial polypeptide to be used in immunization can be carried out with reference to publications WO 2010 / 016526, WO 2011 / 096517, WO 2011 / 096528, WO 2011 / 096519, WO 2011 / 096533, WO 2011 / 096534, WO 2011 / 096535, WO 2013 / 018886, WO 2013 / 018894, WO 2013 / 018892, WO 2013 / 018891, WO 2013 / 018889, WO 2013 / 018883, WO 2013 / 125636, WO 2013 / 125654, WO 2013 / 125630, WO 2013 / 125640, WO 2013 / 147169, WO 2013 / 147176 and WO 2015 / 020212.

[039] Specific examples of the anti-CAPRIN-1 antibody according to the present invention include the anti-CAPRIN-1 antibodies described in publications WO 2010 / 016526, WO 2011 / 096517, WO 2011 / 096528, WO 2011 / 096519, WO 2011 / 096533, WO 2011 / 096534, WO 2011 / 096535, WO 2013 / 018886, WO 2013 / 018894, WO 2013 / 018892, WO 2013 / 018891, WO 2013 / 018889, WO 2013 / 018883, WO 2013 / 125636, WO 2013 / 125654, WO 2013 / 125630, WO 2013 / 125640, WO 2013 / 147169, WO 2013 / 147176 and WO 2015 / 020212 mentioned above. Examples of the antibody, preferably. Petition 870260047669, dated 05 / 19 / 2026, page 36 / 272 24 / 116 anti-CAPRIN-1 includes the following.

[040] An antibody or a fragment thereof that has immunological reactivity with the amino acid sequence represented by SEQ ID NO: 2 or SEQ ID NO: 4 or a partial polypeptide of the CAPRIN1 protein that has an amino acid sequence that has 80% or more (preferably 85% or more, more preferably 90% or more, even more preferably 95% or more, still more preferably 99% or more) of sequence identity with the amino acid sequence represented by SEQ ID NO: 2 or SEQ ID NO: 4.

[041] An antibody or a fragment thereof that has immunological reactivity with a partial polypeptide of the CAPRIN-1 protein that has the amino acid sequence represented by SEQ ID NO: 31 or an amino acid sequence that has 80% or more (preferably 85% or more, more preferably 90% or more, most preferably 95% or more) of sequence identity with the amino acid sequence.Preferably, an antibody or a fragment thereof comprising a variable heavy chain region comprising the complementarity-determining regions of SEQ ID NOs: 36, 37 and 38 (CDR1, CDR2 and CDR3, respectively) and a variable light chain region comprising the complementarity-determining regions of SEQ ID NOs: 40, 41 and 42 (CDR1, CDR2 and CDR3, respectively) and possessing immunological reactivity with the CAPRIN-1 protein; an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 140, 141 and 142 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 143, 144 and 145 (CDR1, CDR2 and CDR3, respectively) and possessing immunological reactivity with the CAPRIN-1 protein; or an antibody or a fragment thereof. Petition 870260047669, dated 05 / 19 / 2026, page 37 / 27225 / 116 even though it comprises a variable region of the heavy chain that includes the complementarity-determining regions of SEQ ID NOs: 164, 165 and 166 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain that includes the complementarity-determining regions of SEQ ID NOs: 167, 168 and 169 (CDR1, CDR2 and CDR3, respectively) and has immunological reactivity with the CAPRIN-1 protein.More preferably, an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 39 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 43; an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 70 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 71; or an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 78 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 79.

[042] An antibody or a fragment thereof that has immunological reactivity with a partial polypeptide of the CAPRIN-1 protein that has the amino acid sequence represented by SEQ ID NO: 33 or an amino acid sequence that has 80% or more (preferably 85% or more, more preferably 90% or more, most preferably 95% or more) of sequence identity with the amino acid sequence. Preferably, an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NO: 60, 61 and 62 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 64, 65 and 66 Petition 870260047669, dated 05 / 19 / 2026, page 38 / 272 26 / 116 (CDR1, CDR2 and CDR3, respectively) and has immunological reactivity with the CAPRIN-1 protein; or an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 63 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 67.

[043] An antibody or a fragment thereof that has immunological reactivity with a partial polypeptide of the CAPRIN-1 protein that has the amino acid sequence represented by SEQ ID NO: 32 or an amino acid sequence that has 80% or more (preferably 85% or more, more preferably 90% or more, most preferably 95% or more) of sequence identity with the amino acid sequence. Preferably, an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 52, 53 and 54 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 56, 57 and 58 (CDR1, CDR2 and CDR3, respectively) and has immunological reactivity with the CAPRIN-1 protein.More preferably, an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 55 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 59.

[044] An antibody or a fragment thereof that has immunological reactivity with a partial polypeptide of the CAPRIN-1 protein that has the amino acid sequence represented by SEQ ID NO: 34 or an amino acid sequence that has 80% or more (preferably 85% or more, more preferably 90% or more, most preferably 95% or more) of sequence identity with the amino acid sequence. Preferably, Petition 870260047669, dated 05 / 19 / 2026, page 39 / 272 27 / 116 an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 170, 171 and 172 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 173, 174 and 175 (CDR1, CDR2 and CDR3, respectively) and possessing immunological reactivity with the CAPRIN-1 protein; or an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 176, 177 and 178 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 179, 180 and 181 (CDR1, CDR2 and CDR3, respectively) and possessing immunological reactivity with the CAPRIN-1 protein.More preferably, an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 80 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 81; or an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 82 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 83.

[045] An antibody or a fragment thereof that has immunological reactivity with a partial polypeptide of the CAPRIN-1 protein having the amino acid sequence represented by SEQ ID NO: 35 or an amino acid sequence that has 80% or more (preferably 85% or more, preferably 90% or more, most preferably 95% or more) of sequence identity with the amino acid sequence. Preferably, an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the determining regions of Petition 870260047669, dated 05 / 19 / 2026, page 40 / 272 28 / 116 complementarity of SEQ ID NOs: 182, 183 and 184 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 185, 186 and 187 (CDR1, CDR2 and CDR3, respectively) and possessing immunological reactivity with the CAPRIN-1 protein; or an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 188, 189 and 190 (CDR1, CDR2, and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 191, 192 and 193 (CDR1, CDR2 and CDR3, respectively) and possessing immunological reactivity with the CAPRIN-1 protein.More preferably, an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 84 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 85; or an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 86 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 87.

[046] An antibody or a fragment thereof comprising a variable heavy chain region comprising the complementarity-determining regions of SEQ ID NOs: 44, 45 and 46 (CDR1, CDR2 and CDR3, respectively) and a variable light chain region comprising the complementarity-determining regions of SEQ ID NOs: 48, 49 and 50 (CDR1, CDR2 and CDR3, respectively) and possessing immunological reactivity with the CAPRIN-1 protein. Preferably, an antibody or a fragment thereof comprising a variable heavy chain region comprising the amino acid sequence of SEQ ID NO: 47 and a variable light chain region comprising the amino acid sequence of SEQ Petition 870260047669, dated 05 / 19 / 2026, page 41 / 272 29 / 116 ID NO: 51.

[047] An antibody or a fragment thereof that has immunological reactivity with a partial polypeptide of the CAPRIN-1 protein that has the amino acid sequence represented by SEQ ID NO: 296 or an amino acid sequence that has 80% or more (preferably 85% or more, more preferably 90% or more, most preferably 95% or more) of sequence identity with the amino acid sequence. Preferably, an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 146, 147 and 148 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 149, 150 and 223 (CDR1, CDR2 and CDR3, respectively) and has immunological reactivity with the CAPRIN-1 protein.Preferably, an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 72 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 73.

[048] An antibody or a fragment thereof that has immunological reactivity with a partial polypeptide of the CAPRIN-1 protein that has the amino acid sequence represented by SEQ ID NO: 297 or an amino acid sequence that has 80% or more (preferably 85% or more, more preferably 90% or more, most preferably 95% or more) of sequence identity with the amino acid sequence. Preferably, an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 272, 273 and 274 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the Petition 870260047669, dated 05 / 19 / 2026, page 42 / 272 30 / 116 regions determining complementarity of SEQ ID NOs: 275, 276 and 277 (CDR1, CDR2 and CDR3, respectively) and possesses immunological reactivity with the CAPRIN-1 protein. More preferably, an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 114 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 115.

[049] An antibody or a fragment thereof that has immunological reactivity with a partial polypeptide of the CAPRIN-1 protein that has the amino acid sequence represented by SEQ ID NO: 298 or an amino acid sequence that has 80% or more (preferably 85% or more, more preferably 90% or more, most preferably 95% or more) of sequence identity with the amino acid sequence. Preferably, an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 290, 291 and 292 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 293, 294 and 295 (CDR1, CDR2 and CDR3, respectively) and has immunological reactivity with the CAPRIN-1 protein.Preferably, an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 120 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 121.

[050] An antibody or a fragment thereof that has immunological reactivity with a partial polypeptide of the CAPRIN-1 protein that has the amino acid sequence represented by SEQ ID NO: 299 or an amino acid sequence that has 80% or more (preferably 85% or Petition 870260047669, dated 05 / 19 / 2026, page 43 / 272 31 / 116 more, more preferably 90% or more, more preferably 95% or more) of sequence identity with the amino acid sequence. Preferably, an antibody or a fragment thereof comprising a variable heavy chain region comprising the complementarity-determining regions of SEQ ID NO: 300, 301 and 302 (CDR1, CDR2 and CDR3, respectively) and a variable light chain region comprising the complementarity-determining regions of SEQ ID NOs: 304, 305 and 306 (CDR1, CDR2 and CDR3, respectively) and possessing immunological reactivity with the CAPRIN-1 protein. More preferably, an antibody or a fragment thereof comprising a variable heavy chain region comprising the amino acid sequence of SEQ ID NO: 303 and a variable light chain region comprising the amino acid sequence of SEQ ID NO: 307.

[051] An antibody or a fragment thereof that has immunological reactivity with a partial polypeptide of the CAPRIN-1 protein that has the amino acid sequence represented by SEQ ID NO: 308 or an amino acid sequence that has 80% or more (preferably 85% or more, more preferably 90% or more, most preferably 95% or more) of sequence identity with the amino acid sequence. Preferably, an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 134, 135 and 136 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 137, 138 and 139 (CDR1, CDR2 and CDR3, respectively) and has immunological reactivity with the CAPRIN-1 protein.Preferably, an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence SEQ ID NO: 68 and a region. Petition 870260047669, dated 05 / 19 / 2026, page 44 / 272 32 / 116 variable of the light chain comprising the amino acid sequence of SEQ ID NO: 69.

[052] An antibody or a fragment thereof that has immunological reactivity with a partial polypeptide of the CAPRIN-1 protein having the amino acid sequence represented by SEQ ID NO: 309 or an amino acid sequence that has 80% or more (preferably 85% or more, more preferably 90% or more, most preferably 95% or more) of sequence identity with the amino acid sequence. Preferably, an antibody or one thereof comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 134, 135 and 136 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 137, 138 and 139 (CDR1, CDR2 and CDR3, respectively) and has immunological reactivity with the CAPRIN-1 protein.Preferably, an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 68 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 69.

[053] Also, the following anti-CAPRIN-1 antibodies are preferably used.

[054] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 68 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 69.

[055] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 70 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 71. Petition 870260047669, dated 05 / 19 / 2026, page 45 / 272 33 / 116

[056] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 72 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 73.

[057] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 74 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 75.

[058] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 76 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 77.

[059] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 78 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 79.

[060] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 80 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 81.

[061] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 82 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 83.

[062] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 84 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 85. Petition 870260047669, dated 05 / 19 / 2026, page 46 / 272 34 / 116

[063] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 86 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 87.

[064] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 88 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 89.

[065] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 90 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 91.

[066] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 92 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 93.

[067] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 94 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 95.

[068] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 96 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 97.

[069] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 98 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 99. Petition 870260047669, dated 05 / 19 / 2026, page 47 / 272 35 / 116

[070] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 100 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 101.

[071] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 102 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 103.

[072] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 104 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 105.

[073] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 106 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 107.

[074] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 108 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 109.

[075] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 110 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 111.

[076] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 112 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 113. Petition 870260047669, dated 05 / 19 / 2026, page 48 / 272 36 / 116

[077] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 114 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 115.

[078] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 116 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 117.

[079] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 118 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 119.

[080] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 120 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 121.

[081] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 122 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 123.

[082] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 124 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 125.

[083] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 126 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 127. Petition 870260047669, dated 05 / 19 / 2026, page 49 / 272 37 / 116

[084] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 128 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 129.

[085] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 130 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 131.

[086] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 132 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 133.

[087] An antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 303 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 307.

[088] In the Examples mentioned later, conjugates with an immune activator were prepared using the polyclonal antibody or the monoclonal antibody against the full-length CAPRIN-1 protein or a polypeptide of a partial region thereof expressed on the cell membrane surface of cancer cells, and it was found to have an intense antitumor effect. <Ativador Imune>

[089] In the present invention, the immune activator is a factor that activates various immunocytes and means a naturally occurring compound, a nucleic acid or a naturally occurring compound capable of maintaining or enhancing the immune functions of cells. In this context, immunocytes are T lymphocytes, B lymphocytes, NK cells, monocytes, cells Petition 870260047669, dated 05 / 19 / 2026, page 50 / 272 38 / 116 dendritic cells, granulocytes, macrophages, myeloid-derived suppressor cells, Langerhans cells and their precursor cell groups, and these immunocyte groups present in the tumor.

[090] Specific examples of the immune activator used in the present invention include, but are not especially limited to, ligands or agonists that bind to Toll-like receptor (TLR), NOD-like receptor (NLR), RIG-like receptor or C-type lectin receptor (CLR).

[091] Specific examples of ligands or agonists that bind to Toll-like receptors (TLRs) include ligands or agonists that bind to TLR2, TLR3, TLR4, TLR5, TLR7, TLR8, TLR9, or TLR10.

[092] Specific examples of the ligand or agonist that binds to TLR2 include selected substances from the group consisting of peptidoglycan, lipoprotein, lipopolysaccharide and zymosan.

[093] Specific examples of the ligand or agonist that binds to TLR3 include selected substances from the group consisting of poly (I:C), poly (A:U) polyICLC (Hiltonol) and Ampligen.

[094] Specific examples of the ligand or agonist that binds to TLR4 include selected substances from the group consisting of lipopolysaccharide (LPS), HSP60, RS09, MPLA (Salmonella minnesota R595 monophosphoryl-lipid A), GLA-SE, G100 and MPLA.

[095] Specific examples of the ligand or agonist that binds to TLR5 include selected substances from the group consisting of flagellin and FLA.

[096] Specific examples of ligands or agonists that bind to TLR7 or TLR8 include low molecular weight compounds such as imidazoquinoline compounds and single-stranded RNA. Specific examples include Imiquimod, Resiquimod, Loxorbine, 852A, 854A, S-34240, Motolimod (VTX-2337), DSR-6434, GS-9620, ANA773, AZD8848 / DSP-3025, Petition 870260047669, dated 05 / 19 / 2026, p. 51 / 272 39 / 116 GSK2245035, Gardiquimod, CL264, UC-1V150, CL075, CL097, CL307, CL347, 3M-003, 3M-0043, 3M-052, CL264, IV209, ORN R-2176-dT, Poly(dT), ORN R0006, ORN R-0002, ORN R-2336, PolyU, ORN R-1886, polyG3, DSR6434, RWJ21757, SM324405, p-IMDQ, m-IMDQ and GSK2245035.

[097] Specific examples of the ligand or agonist that binds to TLR9 include selected substances from the group consisting of bacterial DNA, unmethylated CpG DNA, hemozoin, ODN1585, ODN1668, ODN1668, lefitolimod (MGN1703), SD-101, CYT003, CPG7909, DUK-CPG-001 and ODN1826.

[098] Specific examples of the ligand or agonist that binds to TLR10 include selected substances from the group consisting of profilin and uropathogenic bacteria.

[099] Among the ligands or agonists that bind to the Toll-like receptor (TLR), the ligand or agonist that binds to TLR7 or TLR8 is preferably used in the present invention. A ligand or agonist that binds to TLR7 or TLR8 selected from the group consisting of imidazoquinoline compounds and single-stranded RNA, more preferably, is used as the ligand or agonist that binds to TLR7 or TLR8, and a ligand or agonist that binds to TLR7 or TLR8 selected from imidazoquinoline compounds, even more preferably, is used.

[0100] Specific examples of the imidazoquinoline compound include the compounds described in US Patent 8951528 and the compounds described in publication WO 2015 / 103989, for example, 1-(2-methylpropyl)-1H-imidazo[4,5-c]quinoline-4-amine (Imiquimod), 1-(4-amino-2-ethylaminomethylimidazo-[4,5-c]quinolin-1-yl)-2-methylpropan-2-ol (Gardiquimod), N-[4-(4-amino-2-ethyl-1H-imidazo[4,5-c]quinolin-1-yl)butyl-]methanesulfonamide (PF4878691), 4-amino-2-(ethoxymethyl)-α,α-dimethyl-1H-imidazo[4,5-c]quinoline-1-ethanol (Resiquimod), 4-amino-aa-dimethyl-2-methoxyethyl-1H-imidazo[4,5] Petition 870260047669, dated 05 / 19 / 2026, page 52 / 272 40 / 116 c]quinoline-1 -ethanol, 1 -(2-(3-(benzyloxy)propoxy)ethyl)-2-(ethoximethyl)-1Himidazo[4,5-c]quinoline-4-amine, 4-amino-2-ethoxymethyl-aa-dimethyl-6,7,8,9tetrahydro-1H-imidazo[4,5-c]quinoline-1 -ethanol, N-(2-{2-[4-amino-2-(2-methoxyethyl)1H-imidazo[4,5-c]quinolin-1 -yl]ethoxy}ethyl)-n'-phenylurea, 1 -2-amino-2-methylpropyl)2-(ethoxymethyl)-1H-imidazo[4,5-c]quinolin-4-amine, 1 -{4-[(3,5dichlorophenyl)sulfonyl]butyl}-2-ethyl-1H-imidazo[4,5-c]quinolin-4-amine, N-(2-{2-[4amino-2-(ethoxymethyl)-1H-imidazo[4,5-c]quinolin-1 -yl]ethoxy}ethyl)-n'-cyclohexylurea, N{3-[4-amino-2-(ethoxymethyl)-1H-imidazo[4,5-c]quinolin-1-yl]propyl}-n'-(3cyanophenyl)thiourea, N-[3-(4-amino-2-butyl-1H-imidazo[4,5-c]quinolin-1 -yl)-2,2dimethylpropyl]benzamida, 2-butyl-1 -[3-(methylsulfonyl)propyl]-1H-imidazo[4,5c]quinolin-4-amine, embora or imidazoquinoline compound is not limited to this extent that the imidazoquinoline compound is a TLR7 or TLR8.

[0101] Specific examples of ligands or agonists that bind to the NOD-like receptor (NLR) include M-TriDAP and PGN. Other examples include ligands or agonists against NOD1, for example, Tri-DAP, iEDAP, and C12-iE. Other examples include ligands or agonists against NOD2, for example, MDP, N-glycosyl-MDP, murabutide, M-TriLyS-D-ASN, MTriLYS, and L18-MDP.

[0102] Specific examples of ligands or agonists that bind to the RIG-like receptor include 5'ppp-dsRNA, poly(dA:dT), poly(dG:dC), and poly(I:C).

[0103] Specific examples of ligands or agonists that bind to the C-type lectin receptor (CLR) include trehalose 6,6-dibehenate, zymosan, WGP, HKSC, HKCA, and curdlan AL. <CONJUGADO de Anticorpo anti-CAPRIN-1 e Ativador Imune>

[0104] In the present invention, the binding method between the anti-CAPRIN-1 antibody and the immune activator in the anti-CAPRIN-1 antibody-immune activator conjugate is not particularly limited as long as it allows the antitumor activity against cancer to be maintained. The binding method, of Petition 870260047669, dated 05 / 19 / 2026, page 53 / 272 41 / 116 preference, has a binding structure formed between the anti-CAPRIN-1 antibody and the immune activator.

[0105] In this context, the ligand means a compound capable of binding the anti-CAPRIN-1 antibody to the immune activator. Any of several ligands known in the art may be used, or a chemical modification suitable to the activator structure may be used to directly bind the antibody to the activator.

[0106] The details of the type of ligand and the method of joining can basically be in accordance with a method known in the state of the art (see, for example, Greg T. Hermanson Bioconjugate Techniques, third edition, publications WO 2004 / 010957 and WO 2014 / 012479).

[0107] In one embodiment of the present invention, examples of reactive groups connected to the anti-CAPRIN-1 antibody, the immune activator and the ligand include the following.

[0108] Examples of the reactive group attached to the amino acid sequence of an antibody or a glycoprotein modifying an amino acid include the primary amine (S-amino group), carboxyl, thiol (sulfhydryl), carbonyl (ketone or aldehyde), and hydroxyl, unless a special chemical modification is performed. The primary amine exists at the N-terminus of a polypeptide or in the secondary chain of a lysine residue and is positively charged under physiological conditions. The primary amine generally exists outside the protein and therefore can be used in binding without denaturing the protein structure. The carboxyl exists at the C-terminus of a polypeptide or in the secondary chain of aspartic acid or glutamic acid. The sulfhydryl exists in the secondary chain of cysteine ​​and forms a disulfide bond that maintains the higher-order structure of the protein. The ketone or aldehyde group is generated in a glycoprotein through the oxidation of glycosyl with sodium metaperiodate.

[0109] The conjugate of the present invention is prepared by joining the Petition 870260047669, dated 05 / 19 / 2026, p. 54 / 272 42 / 116 ligand to the reactive group of the antibody, binding to the immune activator bound to the ligand or directly binding the immune activator to the antibody.

[0110] Examples of reactive groups attached to the ligand and immune activator include the following.

[0111] The reactive group capable of reacting with the amine: N-hydroxysuccinimide ester (NHS), imide ester, pentafluorophenyl ester, hydroxymethyl phosphine, isothiocyanate, isocyanate, acyl azide, N-hydroxyl ester, sulfonyl chloride, aldehyde, glyoxal, epoxide, oxirane, carbonate, aryl, imide ester, carbodiimide and carboxylic anhydride.

[0112] The reactive group capable of reacting with the carboxyl and amine groups: carbodiimide, diazoalkane, diazoacetyl compounds and carbonyldiimidazole.

[0113] The reactive group capable of reacting with thiol: maleimide, haloacetamide, pyridyl disulfide, thiosulfone, vinyl sulfone, haloacetyl, aziridine, acryloyl and aryl.

[0114] The reactive group capable of reacting with the aldehyde: hydrazide and alkoxyamine. The reactive group capable of reacting with the hydroxyl: epoxy, oxirane, carbonyldiimidazole, N,N'-disuccinimidyl carbonate, Nhydroxysuccinimidyl chloroformate and isocyanate.

[0115] The reactive group capable of reacting with the hydroxyl group: the isocyanate.

[0116] The photoreactive group: diaziridine, aryl azide, aryl, benzophenol and diazo compounds.

[0117] Specific examples of the ligand that has the reactive group include the following.

[0118] As a ligand possessing the same reactive group, a ligand possessing the N-hydroxysuccinimide ester as a reactive group (e.g., disuccinimidyl glutarate (DSG), disuccinimidyl suberate (DSS), bis(sulfosuccinimidyl)suberate (BS3), tris-(succinimidyl)aminotriacetate (TSAT), PEGylated bis(sulfosuccinimidyl)suberate (BS(PEG)5, BS(PEG)9), Petition 870260047669, dated 05 / 19 / 2026, page 55 / 272 43 / 116 dithiobis(succinimidyl propionate) (DSP), (DTSSP), (EGS), (Sulfo-EGS), (DMA), (DMP), (DMS), (DTBP), (DFDNB), (DST), (BSOCOES), (EGS), (SulfoEGS)) and a ligand that has maleimide as a reactive group (e.g., (BMOE), (BMB), (BMH), (TMEA), (BM(PEG)2), (BM(PEG)3), (DTME) and (DMDB)).

[0119] As a ligand having different reactive group ends, a ligand having the NHS ester and maleimide as reactive groups (e.g., AMAS, BMPS, GMBS, Sulfo-MBS, MBS, Sulfo-MBS, SMCC, Sulfo-SMCC, EMCS, Sulfo-EMCS, SMPB, Sulfo-SMPB, SMPF, LCSMCC, Sulfo-KMUS, SM(PEG)2, SM(PEG)4, SM(PEG)6, SM(PEG)8, SM(PEG)i2 and SM(PEG)24), a ligand having the NHS ester and pyridylthiol as reactive groups (e.g., SPDP, LC-SPDP, Sulfo-LC-SPDP, SMPT, PEG4-SPDP and PEG12-SPDP), a ligand having the NHS ester and haloacetyl as reactive groups (e.g., SIA, SBAP, SIAB and Sulfo-SIAB), a a ligand that has NHS ester and aryl azide as reactive groups (e.g., ANB-NOS, Sulfo-SANPAH, and ATFB), a ligand that has NHS ester and diaziridine as reactive groups (e.g., SDA, Sulfo-SDA, LC-SDA, SDAD, and SulfoSDAD), a ligand that has carbodiimide as reactive groups (e.g., DCC, EDC, EDAC, NHS, and Sulfo-NHS),A ligand that has maleimide and hydrazide as reactive groups (e.g., BMPH, EMCH, MPBH, and KMUH), a ligand that has pyridylthiol and hydrazide as an active group (e.g., PDPH), a ligand that has isocyanate and maleimide as reactive groups (e.g., PMPI), and a ligand that has NHS ester and psoralen as reactive groups (e.g., SPB).

[0120] Like other ligands, a ligand that contains a polypeptide, for example, Fmoc-Ala-Ala-Asn-PAB, Fmoc-Ala-Ala-Asn(Trt)PAB, Fmoc-PEG3-Ala-Ala-Asn(Trt)-PAB, Fmoc-PEG4-Ala-Ala-Asn(Trt)-PAB, Fmoc-Ala-Ala-Asn-PAB-PNP, Fmoc-Ala-Ala-Asn(Trt)-PAB-PNP, Fmoc-PEG3Ala-Ala-Asn(Trt)-PAB-PNP, Azide-PEG4-Ala-Ala-Asn(Trt)-PAB-PNP, Mal-PEG4 Petition 870260047669, dated 05 / 19 / 2026, page 56 / 272 44 / 116 Ala-Ala-Asn(Trt)-PAB-PNP, Fmoc-Val-Cit-PAB-OH, Val-Cit-PAB-OH, Fmoc-ValCit-PAB-PNP, MC-Val-Cit-PAB, MC-Val-Cit-PAB-PNP.

[0121] Also Bis-PEG acid, PEG acid (e.g., PEG-TEMPO acid, Amino-PEG acid, Amino-PEG-CH2CO2H, Amino-PEG acid, Azido-PEG acid, Carboxy-PEG-sulfonic acid, Fmoc-N-amido-PEG acid, Fmoc-N-amido-PEG-CH2CO2H, Fmoc-aminooxyPEG acid, Hydroxy-PEG acid, Hydroxy-PEG-CH2CO2H, m-PEG acid, m-PEG-(CH2)3 acid, Methoxytritil-N-PEG acid, N-methyl-N-(t-Boc)-PEG acid, Propargyl-PEG acid, Propargyl-PEG-CH2CO2H, Propargyl-PEG(CH2)3 acid, t-Boc-N-amido-PEG acid, t-Boc-N-amido-PEG-CH2CO2H, t-Boc-Aminooxy-PEG acid, PEG-PFP acid ester, miscellaneous PEG acid), PEG PFP ester (e.g., PEG-PFP acid ester, Bis-PEG-PFP ester), Bis-PEG-NHS, PEG aldehyde (e.g., m-PEG aldehyde, m-PEG benzaldehyde, Ald-PEG acid, Ald-PEG-amine, Ald-PEG-azide, Ald-PEG-NH-Boc, Ald-PEG-NHS ester, Ald-PEG-TFP ester, Ald-PEG-t-butyl ester), PEG Tosylate (e.g., Azido-PEG-Tos, Hydroxy-PEG-Tos, m-PEG-Tos,t-Boc-Aminooxy-PEG-Tos, Trifluoroethyl-PEG-Tos, Tos-PEG acid, Tos-PEGCH2CO2H, Tos-PEG-alkyne, Tos-PEG-t-butyl ester, Tos-PEG-CH2CO2tBu, Tos-PEG-Tos, S-acetyl-PEG6-Tos, N-Tos-N-(t-butoxycarbonyl)-aminooxy-PEG4Tos, Ms-PEG-Ms, Ms-PEG-t-butyl ester, PEG-Ms, Propargyl-PEG-Ms), BocPEG (e.g., Amino-PEG-t-Boc-Hydrazide, Azido-PEG-t-Boc-Hydrazide, Boc-NH-PEG-NH-Boc, Bromoacetamido-PEG-Boc-amine, m-PEG-ONHBoc, Mal-Alkyl-t-Boc-amine, alcohol of N-Boc-PEG, N-Boc-PEG-bromide, N-methyl-N-(t-Boc)-PEG acid, t-Boc-N-amido-PEG acid, t-Boc-N-amido-PEGCH2CO2H, t-Boc-N-amido-PEG-amine, t-Boc-N-amido-PEG-azide, tBoc-N-amido-PEG-NHS ester, t-Boc-N-amido-PEG-sulfonic acid), PEG NHS ester (e.g., PEG-NHS acid ester, Azido-PEG-NHS ester, Bis-PEG-NHS, Fmoc-PEG-NHS ester, m-PEG-NHS ester, carbonate of, Petition 870260047669, dated 05 / 19 / 2026, p. 57 / 272 45 / 116 m-PEG-NHS, Mal-PEG-NHS ester, Proparyl-PEG-NHS ester, tBoc-N-amido-PEG-NHS ester, t-Butoxycarbonyl-PEG-NHS ester), Fmoc-PEG (for example, Fmoc-N-amido-PEG acid, Fmoc-NH-PEG-CH2CO2H, ester of Fmoc-PEG-NHS), PEG of biotin (for example, PEG acid of biotin, PEG alcohol of biotin, PEG-alquino of biotin, PEG-amine of biotin, PEGazide of biotin, PEG-DBCO of biotin, PEG-hydrazide of biotin, biotin-PEGMal, biotin-PEG-NHS, biotin-EDA-PEG-NHS, biotin-PEG-oxamine, biotin-PEGPFP, biotin-EDA-PEG-PFP, biotin-PEG-Tetrazine, biotin-PEG-TFP, azida-SSbiotin, biotin-PEG3-SS-azida, DBCO-SS-PEG3-biotin, Dde biotin-PEG4Alquino, Dde biotin-PEG4-azida, Dde biotin-PEG4-DBCO, Diazo biotin-PEG3Alquino, Diazo biotin-PEG3-azida, Diazo biotin-PEG3-DBCO, Diol biotin-PEG3Alquino, Diol biotin-PEG3-azida, PC biotin-PEG3-Alquino, PC-biotin-PEG4PEG4-Alquino, PC-biotin-PEG4-PEG4-Alquino, PC biotin-PEG3-azida, PC-biotinPEG4-PEG3-azide, PC-biotin-PEG4-NHS carbonate,PC DBCO-PEG3-biotin, WSPC biotin-PEG3-DBCO, Fmoc-Lys(biotin-PEG)-OH, Fmoc-N-amido(PEG-biotin) acid, TAMRA-azide-PEG-biotin), PEG phosphate, Aminooxy PEG (e.g., Aminooxy-PEG acid, Aminooxy-PEG alcohol, AminooxyPEG-azide, Aminooxy-PEG-bromide, Aminooxy-PEG-methane, Aminooxy-PEGPropargyl, Aminooxy-PEG-t-butyl ester, Aminooxy-PEG-thiol, Bis-(Aminooxy)PEG, t-Boc-Aminooxy-PEG acid, t-Boc-Aminooxy-PEG alcohol, t-BocAminooxy-PEG-amine, t-Boc-Aminooxy-PEG-azide, t-Boc-Aminooxy-PEGBromide, t-Boc-Aminooxy-PEG-Methane, t-Boc-Aminooxy-PEG-Propargyl, t-Bocaminooxy-PEG-S-Ac, t-Boc-Aminooxy-PEG-Thiol, t-Boc-Aminooxy-PEG-Tos, Fmoc-aminooxy-PEG acid, Trifluoroethyl-PEG-Aminooxy), Alkyne PEG (e.g. endo-BCN-PEG, exo-BCN-PEG, Propargyl-PEG, PropargylPEG-CH2CO2H, Propargyl-PEG-(CH2)3 acid, Propargyl-PEG-(CH2)3methyl ester, Propargyl-PEG-Acrylate, Propargyl-PEG alcohol, Propargyl-PEG-amine, Propargyl-PEG-methylamine, Aminooxy-PEG-Propargyl,Propargil-PEG-azide, Petition 870260047669, dated 05 / 19 / 2026, p. 58 / 272 46 / 116 Propargyl-PEG-bromide, Propargyl-PEG-Maleimide, Propargyl-PEG-Ms, Propargyl-PEG-NHS ester, Propargyl-PEG-sulphonic acid, Propargyl-PEG-butyl ester, Propargyl-PEG-CH2CO2tBu, Propargyl-PEG-Tiol, Propargyl-PEG-Carbontrophenol-5 t-Boc-aminooxy-PEG-Propargyl, Bis-Propargyl-PEG, m-PEGPropargyl), Azide PEG (e.g., Azido-PEG acid, Azido-PEGCH2CO2H, Azido-PEG-(CH2)3-methyl ester, Azido-PEG-Acrylate, Azido-PEG alcohol, Azido-PEG-(CH2)3OH, Azido-PEG-amine, Azido-PEG-azide, AzidoPEG-Maleimide, Azido-PEG-methylamine, Azido-PEG-methyl ester, Azido-PEG-NHS ester, Azido-PEG-CH2CO2-NHS, Azido-PEG-oxazole, Azido-PEG-2FP Azido-PEG-phosphonic acid, AzidoPEG-phosphonic acid ethyl ester, Azido-PEG-sulfonic acid, Azido-PEG-t-Boc-Hydrazide, Azido-PEG-t-butyl ester, Azido-PEG-CH2-CO2-t-butyl ester, Azido-PEG-TPG-butyl ester, Azido-PEG-Tos, Aminooxy-PEG-azide, Bromo-PEG-azide, Bromoacetamido-PEG-azide, 110-PEG-Carboxyrhodamine-azide, Isothiocyanate-PEG-azide, Isothiocyanate-PEG-azide, m-PEG-azide, PropargylPEG-azide, TAMRA-PEG-azide, t-Boc-N-Amido-PEG-azide, t-Boc-AminooxyPEG-azide, Thiol-PEG-azide, Trifluoroethyl-PEG-azide, Azido-PEGamino acid, carbonate Azido-PEG4-4-nitrophenyl, S-Acetyl-PEG3-Azido, azide, TritylPEG10-azide), Alkyne PEG, DBCO-PEG, BCN-PEG, Propargyl-PEG, Bis-PEG acid, Bis-PEG-NHS, Bis-PEG-PFP, Bis-Propargyl-PEG, Amine-PEG-Amine, Azido-PEG-azide, Bromo-PEG or Mal PEG can be used.

[0122] The linker between the anti-CAPRIN-1 antibody and the immune activator may consist of a single linker or a plurality of linkers.

[0123] A method for preparing the anti-CAPRIN-1 antibody conjugate and the immune activator, according to the present invention, includes a method involving the joining of the immune activator using an S-Amino group on the lysine secondary chain of the antibody and a method involving the joining Petition 870260047669, dated 05 / 19 / 2026, page 59 / 272 47 / 116 of the immune activator using the thiol formed through the reduction treatment of a cysteine ​​residue constituting the disulfide bond of the antibody.

[0124] In the case of using an S-Amino group on the lysine residue of the antibody, for example, a method is used that involves the reaction of the active ester (e.g., N-hydroxysuccinimide ether) with it to form an amide bond. In this case, since the antibody contains a large number of lysine residues, the bonding reaction proceeds in a non-specific manner.

[0125] In the case of using a thiol forming a disulfide bond present in the cysteine ​​secondary chain of the antibody, a method is used that involves the formation of a thiol from the disulfide bond in the antibody using a reducing agent such as mercaptoethanol and the reaction of the thiol with maleimide or α-haloamide. For example, a method using phenyloxadiazole sulfone, a 4-cyanoethinyloxy derivative, or similar is used to stabilize a thiol-mediated bond. These bonds are stable for longer than the bond based on the conjugate addition reaction of cysteine ​​with maleimide. A ligand possessing an amino group near an imide group can also be used, since an imide ring with a thiol group added to the maleimide is opened through hydrolysis, so that stability is enhanced due to the resulting amide bond. In the antibody, the thiols of the cysteines form a disulfide bond.Therefore, an alternative method involves linking the immune activator and similar substances between two thiols via thiols. As an example, a crosslink can be formed using a ligand that has two disulfide binding sites, which can be formed from an amide group that has two sulfones in the β position or dibromomaleimide.

[0126] The conjugate of the present invention can be obtained through a method using, for example, the THIOMAB™ technique, which is a method Petition 870260047669, dated 05 / 19 / 2026, page 60 / 272 48 / 116 capable of introducing a specific number of thiol groups into a particular site on an antibody (see Nature Biotechnology 26, 925-932). (2008)).

[0127] The conjugate of the present invention can be formed, for example, by reducing the antibody using a dithiothreitol (DTT) reducing agent in a phosphate buffer to obtain an antibody possessing a reactive thiol group, which is then conjugated with the immune activator. The conjugate can be obtained by adding a thiol group to the primary amine at the lysine residue of the antibody by introducing a Traut reagent (2-iminothiolane or N-succinimidyl S-acetylthioacetate (SATA)), instead of the method using a reducing agent.

[0128] The amount of thiol added to the antibody can be determined, for example, by mixing a sample solution containing 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB) and an SH group with a phosphate buffer solution (pH 8.0) and distilled water, adding a DTNB solution dissolved in a phosphate buffer, a Good buffer or a Tris mixing buffer and incubating the resulting mixture for a specified time, followed by measuring the absorbance at 412 nm (see GL Ellman, Arch Biochem Biophys, 82, 70 (1959)).

[0129] The thiol group added by cleaving the antibody disulfide bond through reduction treatment is preferably treated (capped) in such a way as to prevent the formation of a disulfide bond again. Capping, for example, can employ N-ethylmaleimide (NEM) or 2-iodoacetamide (IAA).

[0130] The conjugate can be constructed by joining the immune activator to the antibody using the thiol group added to the antibody, according to a method known in the art. Specifically, the joining can be performed using, for example, a linking reagent that has a maleimide group or a bromoacetamide group as a linking reagent that binds Petition 870260047669, dated 05 / 19 / 2026, page 61 / 272 49 / 116 specifically to the thiol group of the reduced antibody. For example, Nsuccinimidyl-4-(N-maleimidomethyl)-cyclohexane-1-carboxylate (SMCC) is used as the ligand which has a maleimide group. In this case, the Nsuccinimide group of SMCC can form an amide bond with an amino group present in the immune activator to obtain the conjugate.

[0131] In another embodiment, an amide bond is first formed on an amino group present in the activator using SMCC. Then, the maleimide group of SMCC bound to the immune activator can react with the thiol group added to the antibody to obtain the conjugate.

[0132] In an alternative embodiment, the antibody conjugate and the immune activator can be formed using two ligands. For example, a primary amino group present in the lysine residue of the antibody is linked to the N-succinimide group of SATA (N-succinimidyl-S-acetylthioacetate) via an amide linkage to add a thiol group to the antibody. SMCC reacts with the immune activator containing an amino group or with the immune activator that has an added amino group, according to a common method to form an amide linkage with the N-succinimide group of SMCC. The maleimide group of SMCC linked to the immune activator can react with the thiol group of SATA linked to the antibody to obtain the conjugate.

[0133] In another alternative embodiment, examples of antibody- and immune activator conjugate preparation include a method using maleimidocaproyl-valine-citrulline-p-aminobenzyloxycarbonyl (MCVal-Cit-PAB) as a ligand. MC-Val-Cit-PAB is a ligand cleavable by intracellular proteinases (e.g., cathepsin B). A thiol group is added to the antibody dissolved in a phosphate buffer using DTT or similar. However, the immune activator possessing an amino group is reacted with the benzyloxycarbonyl (PAB) in MC-Val-Cit-PAB to prepare an MC-Val-Cit-PAB-bound immune activator that can then react with the Petition 870260047669, dated 05 / 19 / 2026, page 62 / 272 50 / 116 added thiol antibody mentioned above to obtain the conjugate.

[0134] In another alternative embodiment, SATA is linked to a primary amino group on the lysine residue of the antibody to add a thiol group to it. However, succinimidyl 3-(2-pyridyldithio)propionate (SPDP) is reacted with the immune activator which has an amino group to form an amide bond with the N-succinimide group of SPDP. In order to obtain a composition comprising the antibody bound to the ligand, for example, a peak fraction of a higher molecular weight compared to the antibody before ligand binding can be separated by applying gel filtration chromatography or similar.

[0135] The number of immune activator molecules bound per antibody molecule in the anti-CAPRIN-1 antibody conjugate and the immune activator of the present invention can be characterized using a method such as mass spectrometry, ELISA, electrophoresis or HPLC based on a method known in the prior art. <Efeito Antitumoral do Conjugado>

[0136] The anti-CAPRIN-1 antibody conjugate and immune activator of the present invention possess cytotoxic activity in vitro or in vivo. Consequently, the antitumor effect of the conjugate of the present invention can be determined by examining its cytotoxic activity against cancer. Cytotoxic activity can be evaluated by: administering the conjugate to an organism with cancer; and examining tumor size over time by measuring tumor size after administration. The antitumor effect of the present invention can also be evaluated by examining survival rate. Alternatively, the antitumor effect of the present invention can be evaluated by examining the ability to produce a cytokine or chemokine. The antitumor effect of the conjugate of the present invention can also be determined by examining Petition 870260047669, dated 05 / 19 / 2026, page 63 / 272 51 / 116 of cancer prevention, metastasis prevention, or recurrence prevention.

[0137] It is expected that the conjugate of the present invention will have a stronger antitumor effect, the greater binding affinity for the CAPRIN-1 protein on the surface of cancer cells that the conjugate possesses. Its association constant (affinity constant) Ka (kon / koff) is preferably at least 107M-1, at least 108M-1, at least 5 x 108M-1, at least 109M-1, at least 5 x 109M-1, at least 1010M-1, at least 5 x 1010M-1, at least 1011M-1, at least 5 x 1011M-1, at least 1012M-1, or at least 1013M-1.

[0138] The ability of the conjugate of the present invention to bind to CAPRIN-1 can be identified by means of binding analysis using, for example, ELISA, Western blot, immunofluorescence or flow cytometry.

[0139] The conjugate of the present invention enhances the antitumor effect compared to the anti-CAPRIN-1 antibody alone, as mentioned above. The preferred enhancement rate is 30% or more, more preferably 40% or more, even more preferably 50% or more, even more preferably 55% or more, even more preferably 60% or more, even more preferably 65% ​​or more, even more preferably 70% or more. The enhancement rate of the antitumor effect through the conjugate of the present invention relative to the anti-CAPRIN-1 antibody alone can be calculated by administering the respective effective amounts to cancer-bearing mice under the same conditions, and comparing the tumor volumes 10 days or later after the start of administration. Pharmaceutical Composition and Method for Treatment and / or Prevention of Cancer

[0140] The target of the pharmaceutical composition for the treatment and / or Petition 870260047669, dated 05 / 19 / 2026, page 64 / 272 52 / 116 prevention of cancer of the present invention is not particularly limited provided that the target is cancer (cells) expressing the CAPRIN-1 protein.

[0141] The terms tumor and cancer used in the present invention mean malignant neoplasm and are used interchangeably.

[0142] The cancer targeted in the present invention may be any cancer that expresses the CAPRIN-1 protein on the cell membrane surface. Preferably, the cancer is breast cancer, kidney cancer, pancreatic cancer, colorectal cancer, lung cancer, brain tumor, stomach cancer, uterine cancer, ovarian cancer, prostate cancer, bladder cancer, esophageal cancer, leukemia, lymphoma, liver cancer, gallbladder cancer, sarcoma, mast cell tumor, melanoma, adrenal cortex cancer, Ewing's tumor, Hodgkin's lymphoma, mesothelioma, multiple myeloma, testicular cancer, thyroid cancer, and head and neck cancer, as mentioned above.

[0143] More specifically, examples of these cancers include, but are not limited to, breast adenocarcinoma, complex breast adenocarcinoma, mixed malignant mammary gland tumor, intraductal papillary adenocarcinoma, lung adenocarcinoma, squamous cell carcinoma, small cell carcinoma, large cell carcinoma, glioma which is a neuroepithelial tissue tumor, glioblastoma, neuroblastoma, ependymoma, neuronal tumor, embryonal neuroectodermal tumor, neurilemmoma, neurofibroma, meningioma, chronic lymphocytic leukemia, lymphoma, gastrointestinal lymphoma, alimentary lymphoma, small to medium type lymphoma, cecal cancer, ascending colon cancer, descending colon cancer, transverse colon cancer, sigmoid colon cancer, rectal cancer, epithelial ovarian cancer, germ cell tumor, stromal cell tumor, ductal carcinoma of the pancreas, invasive ductal carcinoma of the pancreas, pancreatic adenocarcinoma, acinar cell carcinoma,adenosquamous carcinoma, tumor of, Petition 870260047669, dated 05 / 19 / 2026, page 65 / 272 53 / 116 giant cells, intraductal papillary-mucinous neoplasm, mucinous cystic neoplasm, pancreatoblastoma, islet cell adenoma, Frants tumor, serous cystadenocarcinoma, solid pseudopapillary tumor, gastrinoma, glucagonoma, insulinoma, multiple endocrine neoplasia type 1 (Wermer syndrome), non-functional islet cell tumor, somatostatinoma, VIPoma, cervical cancer, uterine body cancer, fibrosarcoma, bone or joint sarcoma, Ewing's sarcoma, Wilms' tumor, hepatoblastoma, soft tissue sarcoma, acute leukemia, chronic leukemia, spinal cord tumor, malignant soft tissue tumor, teratoma group tumor, and head and neck cancer including hypopharyngeal cancer, oropharyngeal cancer, tongue cancer, epipharyngeal cancer, mouth cancer, lip cancer, cancer of Breast and throat cancer.

[0144] The individuals (patients) to be targeted are preferably mammals, for example, mammals including primates, pets, livestock and sport animals and, especially preferably, humans, dogs and cats.

[0145] In the case of using the conjugate used in the present invention in a pharmaceutical composition, the pharmaceutical composition can be formulated using a method known to those skilled in the art. For example, the pharmaceutical composition can be used in the form of a parenteral injection of an aseptic solution or suspension with water or any other pharmaceutically acceptable liquid. For example, the conjugate can be formulated in a unit dosage form necessary for generally accepted pharmaceutical practice by mixing with pharmacologically acceptable vehicles or media, specifically, sterile water, physiological saline solution, a vegetable oil, an emulsifier, a suspending agent, a surfactant, a stabilizer, a fragrance, an excipient, a binder, and the like in suitable combination. The effective amount of the active ingredient Petition 870260047669, dated 05 / 19 / 2026, page 66 / 272 54 / 116 in such a preparation is determined in such a way that an appropriate dose within the prescribed range can be achieved.

[0146] An aseptic composition for injection may be formulated according to conventional pharmaceutical practice using a vehicle such as distilled water for injection. Examples of aqueous solutions for injection include physiological saline, isotonic solutions containing glucose and other auxiliary agents, for example, D-sorbitol, D-mannose, D-mannitol and sodium chloride. These solutions may be used in combination with a suitable solubilizer, for example, an alcohol (specifically, ethanol) or a polyalcohol (for example, propylene glycol and polyethylene glycol), or a non-ionic surfactant, for example, Polysorbate 80™ or HCO₃™. Examples of oil solutions include sesame oil and soybean oil. These solutions may be used in combination with benzyl benzoate or benzyl alcohol as a solubilizer.The solutions may also be mixed with a buffer (e.g., a phosphate buffer solution and a sodium acetate buffer solution), a sedative (e.g., procaine hydrochloride), a stabilizer (e.g., benzyl alcohol and phenol), and an antioxidant. Injectable solutions prepared in this manner are typically delivered into suitable ampoules.

[0147] Administration is performed orally or parenterally, preferably parenterally. Specific examples of its dosage forms include injections, intranasal preparations, transpulmonary preparations, and percutaneous preparations. Examples of injections include intravenous injection, intramuscular injection, intraperitoneal injection, subcutaneous injection, and intratumoral administration, through which the pharmaceutical composition can be administered systemically or locally.

[0148] Furthermore, the method of administration can be Petition 870260047669, dated 05 / 19 / 2026, page 67 / 272 55 / 116 appropriately selected in view of a patient's age, weight, sex, symptoms, and so forth. The dose of a pharmaceutical composition containing the antibody or a polynucleotide encoding the antibody may be selected within a range, for example, from 0.0001 to 1,000 mg / kg of body weight per dose. Alternatively, the dose may be selected within a range, for example, from 0.001 to 100,000 mg / kg of body weight per patient, although the dose is not necessarily limited to these numerical values. Although the dose and method of administration vary depending on a patient's weight, age, sex, symptoms, and so forth, those skilled in the art may appropriately select the dose and method.

[0149] The pharmaceutical composition for the treatment and / or prevention of cancer comprising the conjugate of the present invention as an active ingredient can be administered to an individual for the treatment and / or prevention of the aforementioned cancer expressing CAPRIN-1 on the cell membrane surface, preferably breast cancer, kidney cancer, pancreatic cancer, colorectal cancer, lung cancer, brain tumor, stomach cancer, uterine cancer, ovarian cancer, prostate cancer, bladder cancer, esophageal cancer, leukemia, lymphoma, liver cancer, gallbladder cancer, sarcoma, mast cell tumor, melanoma, adrenal cortex cancer, Ewing's tumor, Hodgkin's lymphoma, mesothelioma, multiple myeloma, testicular cancer, thyroid cancer and head and neck cancer. Examples

[0150] Hereafter, the present invention will be specifically described with reference to the Examples. However, the scope of the present invention is not intended to be limited by these specific Examples. Example 1 Anti-CAPRIN-1 Polyclonal Antibody

[0151] In order to obtain anti-CAPRIN-1 polyclonal antibodies Petition 870260047669, dated 05 / 19 / 2026, pp. 68 / 272 56 / 116 rabbits that exhibit immunological reactivity with the CAPRIN-1 protein to be used in conjugates, 1 mg of a recombinant human CAPRIN-1 protein with SEQ ID NO: 2 or SEQ ID NO: 4 produced according to Example 3 of publication WO 2010 / 016526 was mixed with an equal volume of incomplete Freund's adjuvant (IFA) solution, and this mixture was administered subcutaneously to rabbits four times every 2 weeks. Blood was then collected to obtain antiserum containing polyclonal antibodies. The obtained antiserum was purified using a (GE Healthcare Bio-Sciences Corp.) to prepare a polyclonal antibody against the CAPRIN-1 protein (anti-CAPRIN-1 polyclonal antibody #1). Additionally, serum from a rabbit obtained without administering an antigen was purified using a G protein carrier in the same manner as described above and used as a rabbit control antibody.

[0152] The following polyclonal antibodies #2 to #6 against partial polypeptides of CAPRIN-1 were obtained in the same manner as in the method for the preparation of the polyclonal antibody against the CAPRIN-1 protein.

[0153] The anti-CAPRIN-1 polyclonal antibody #2 against a partial CAPRIN-1 polypeptide represented by SEQ ID NO: 37 described in publication WO 2011 / 096528 (SEQ ID NO: 31 of the present specification), anti-CAPRIN-1 polyclonal antibody #3 against a partial polypeptide represented by SEQ ID NO: 5 described in publication WO 2013 / 018894 (SEQ ID NO: 32 of the present description), anti-CAPRIN-1 polyclonal antibody #4 against a partial polypeptide represented by SEQ ID NO: 5 described in publication WO 2013 / 125654 (SEQ ID NO: 33 of the present specification), anti-CAPRIN-1 polyclonal antibody #5 against a partial polypeptide represented by SEQ ID NO: 37 described in publication WO 2011 / 096533 (SEQ ID NO: 34 of the present specification) and the polyclonal antibody anti-CAPRIN-1 #6 against a partial polypeptide represented by SEQ ID NO: 37 described in publication WO 2011 / 096534 (SEQ ID NO: 35 of this specification). Petition 870260047669, dated 05 / 19 / 2026, page 69 / 272 57 / 116 Example 2 Anti-CAPRIN-1 Monoclonal Antibody

[0154] The following anti-CAPRIN-1 monoclonal antibodies were used in the conjugate of the present invention.

[0155] The monoclonal antibody against CAPRIN-1 described in publication WO 2011 / 096528, wherein the antibody comprises the CDR1, CDR2 and CDR3 of the variable region of the heavy chain consisting of the amino acid sequences of SEQ ID NOs: 36, SEQ ID NOs: 37 and SEQ ID NO: 38, respectively, and CDR1, CDR2 and CDR3 of the variable region of the light chain consisting of the amino acid sequences of SEQ ID NO: 40, SEQ ID NO: 41 and SEQ ID NO: 42, respectively (for example, an antibody comprising the amino acid sequence of a variable region of the heavy chain represented by SEQ ID NO: 39 comprising the CDR1, CDR2 and CDR3 of the variable region of the heavy chain and the amino acid sequence of a variable region of the light chain represented by SEQ ID NO: 43 comprising the CDR1, CDR2 and CDR3 of the variable region of the light chain).

[0156] The monoclonal antibody against CAPRIN-1 described in publication WO 2015 / 020212, wherein the antibody comprises the CDR1, CDR2 and CDR3 of the variable region of the heavy chain consisting of the amino acid sequences of SEQ ID NO: 44, SEQ ID NO: 45 and SEQ ID NO: 46, respectively, and CDR1, CDR2 and CDR3 of the variable region of the light chain consisting of the amino acid sequences of SEQ ID NO: 48, SEQ ID NO: 49 and SEQ ID NO: 50, respectively (for example, an antibody comprising the amino acid sequence of a variable region of the heavy chain represented by SEQ ID NO: 47 comprising the CDR1, CDR2 and CDR3 of the variable region of the heavy chain and the amino acid sequence of a variable region of the light chain represented by SEQ ID NO: 51 comprising the CDR1, CDR2 and CDR3 of the variable region of the light chain). Petition 870260047669, dated 05 / 19 / 2026, pp. 70 / 272 58 / 116

[0157] The monoclonal antibody against CAPRIN-1 described in publication WO 2011 / 096519, wherein the antibody comprises the CDR1, CDR2 and CDR3 of the variable region of the heavy chain consisting of the amino acid sequences of SEQ ID NO: 52, SEQ ID NO: 53 and SEQ ID NO: 54, respectively, and CDR1, CDR2 and CDR3 of the variable region of the light chain consisting of the amino acid sequences of SEQ ID NO: 56, SEQ ID NO: 57 and SEQ ID NO: 58, respectively (for example, an antibody comprising the amino acid sequence of a variable region of the heavy chain represented by SEQ ID NO: 55 comprising the CDR1, CDR2 and CDR3 of the variable region of the heavy chain and the amino acid sequence of a variable region of the light chain represented by SEQ ID NO: 59 comprising the CDR1, CDR2 and CDR3 of the variable region of the light chain).

[0158] The monoclonal antibody against CAPRIN-1 described in publication WO 2013 / 125654, wherein the antibody comprises the CDR1, CDR2 and CDR3 of the variable region of the heavy chain consisting of the amino acid sequences of SEQ ID NO: 60, SEQ ID NO: 61 and SEQ ID NO: 62, respectively, and CDR1, CDR2 and CDR3 of the variable region of the light chain consisting of the amino acid sequences of SEQ ID NO: 64, SEQ ID NO: 65 and SEQ ID NO: 66, respectively (for example, an antibody comprising the amino acid sequence of a variable region of the heavy chain represented by SEQ ID NO: 63 comprising the CDR1, CDR2 and CDR3 of the variable region of the heavy chain and the amino acid sequence of a variable region of the light chain represented by SEQ ID NO: 67 comprising the CDR1, CDR2 and CDR3 of the variable region of the light chain).

[0159] The monoclonal antibody against CAPRIN-1 described in publication WO 2011 / 096517, wherein the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 68 and the amino acid sequence of Petition 870260047669, dated 05 / 19 / 2026, pp. 71 / 272 59 / 116 a variable region of the light chain represented by the amino acid sequence SEQ ID NO: 69.

[0160] The monoclonal antibody against CAPRIN-1 described in publication WO 2011 / 096528, wherein the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 70 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 71; the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 72 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 73; the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 74 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 75;The antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 76 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 77; or the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 78 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 79.

[0161] The monoclonal antibody against CAPRIN-1 described in publication WO 2011 / 096533, wherein the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 80 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence Petition 870260047669, dated 05 / 19 / 2026, page 72 / 272 60 / 116 of SEQ ID NO: 81, or the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 82 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 83.

[0162] The monoclonal antibody against CAPRIN-1 described in publication WO 2011 / 096534, wherein the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 84 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 85, or the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 86 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 87.

[0163] The monoclonal antibody against CAPRIN-1 described in publication WO 2010 / 016526, wherein the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 88 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 89; the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 90 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 91; the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 92 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 93; the antibody Petition 870260047669, dated 05 / 19 / 2026, page 73 / 27261 / 116 comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 94 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 95; the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 96 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 97; the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 98 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 99;or the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 100 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 101.;

[0164] The monoclonal antibody against CAPRIN-1 described in publication WO 2013 / 018894, wherein the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 102 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 103, or the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 104 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 105.

[0165] The monoclonal antibody against CAPRIN-1 described in publication WO 2013 / 018892, wherein the antibody comprises the sequence of Petition 870260047669, dated 05 / 19 / 2026, pp. 74 / 272 62 / 116 amino acids from a variable region of the heavy chain represented by the amino acid sequence SEQ ID NO: 106 and the amino acid sequence from a variable region of the light chain represented by the amino acid sequence SEQ ID NO: 107.

[0166] The monoclonal antibody against CAPRIN-1 described in publication WO 2013 / 018891, wherein the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 108 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 109.

[0167] The monoclonal antibody against CAPRIN-1 described in publication WO 2013 / 018889, wherein the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 110 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 111.

[0168] The monoclonal antibody against CAPRIN-1 described in publication WO 2013 / 018883, wherein the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 112 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 113.

[0169] The monoclonal antibody against CAPRIN-1 described in publication WO 2013 / 125636, wherein the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 114 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 115. Petition 870260047669, dated 05 / 19 / 2026, pp. 75 / 272 63 / 116

[0170] The monoclonal antibody against CAPRIN-1 described in publication WO 2013 / 125654, wherein the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 116 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 117, or the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 118 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 119.

[0171] The monoclonal antibody against CAPRIN-1 described in publication WO 2013 / 125630, wherein the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 120 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 121.

[0172] The monoclonal antibody against CAPRIN-1 described in publication WO 2015 / 020212, wherein the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 122 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 123; the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 124 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 125; the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 126 and the amino acid sequence Petition 870260047669, dated 05 / 19 / 2026, pp. 76 / 272 64 / 116 of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 127; the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 128 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 129; the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 130 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 131; or the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 132 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 133.

[0173] A nucleotide sequence was designed to express a variable region of the heavy chain comprising CDR1, CDR2, and CDR3 consisting of the amino acid sequences SEQ ID NO: 36, SEQ ID NO: 37, and SEQ ID NO: 38, respectively, which are from one of the aforementioned anti-CAPRIN-1 monoclonal antibodies and the structure region sequences of a human antibody. The nucleotide sequence was inserted into a mammalian expression vector with an insert encoding a constant region of the human IgG1 heavy chain.Similarly, a nucleotide sequence was designed to express a variable region of the light chain comprising CDR1, CDR2, and CDR3, consisting of the amino acid sequences SEQ ID NO: 40, SEQ ID NO: 41, and SEQ ID NO: 42, respectively, and the sequences of the structure region of a human antibody; and the nucleotide sequence was inserted into a mammalian expression vector with an insert encoding a constant region of the chain. Petition 870260047669, dated 05 / 19 / 2026, page 77 / 272 65 / 116 human IgG1 light. These two recombinant expression vectors were transferred to mammalian cells according to a conventional method, and a culture supernatant containing humanized monoclonal antibody #1 (humanized antibody #1) against CAPRIN-1 comprising CDR1, CDR2, and CDR3 of the variable region of the heavy chain with amino acid sequences SEQ ID NO: 36, SEQ ID NO: 37, and SEQ ID NO: 38, respectively, and CDR1, CDR2, and CDR3 of the variable region of the light chain consisting of amino acid sequences SEQ ID NO: 40, SEQ ID NO: 41, and SEQ ID NO: 42, respectively, were obtained from the cells.

[0174] In a similar manner, a nucleotide sequence was designed to express a variable region of the heavy chain represented by SEQ ID NO: 47 comprising CDR1, CDR2 and CDR3 consisting of the amino acid sequences of SEQ ID NO: 44, SEQ ID NO: 45 and SEQ ID NO: 46, respectively, and the sequences of the structure region of a human antibody; and the nucleotide sequence was inserted into a mammalian expression vector with an insert encoding a constant region of the human IgG1 heavy chain.Similarly, a nucleotide sequence was designed to express a variable region of the light chain represented by SEQ ID NO: 51 comprising CDR1, CDR2, and CDR3, consisting of the amino acid sequences of SEQ ID NO: 48, SEQ ID NO: 49, and SEQ ID NO: 50, respectively, and the sequences of the structure region of a human antibody; and the nucleotide sequence was inserted into a mammalian expression vector with an insert encoding a constant region of the human IgG1 heavy chain. These two recombinant expression vectors were transferred to mammalian cells according to a conventional method, and a culture supernatant containing the humanized anti-CAPRIN-1 monoclonal antibody #2 (humanized antibody #2) comprising the CDR1, CDR2, and CDR3 of the variable region of the heavy chain of the IgG1 was produced. Petition 870260047669, dated 05 / 19 / 2026, pp. 78 / 272 66 / 116 amino acid sequences from SEQ ID NO: 44, SEQ ID NO: 45 and SEQ ID NO: 46, respectively, and CDR1, CDR2 and CDR3 from the variable region of the light chain consisting of amino acid sequences from SEQ ID NO: 48, SEQ ID NO: 49 and SEQ ID NO: 50, respectively, were obtained from the cells.

[0175] A culture supernatant containing the humanized anti-CAPRIN-1 monoclonal antibody #3 (humanized antibody #3) comprising CDR1, CDR2, and CDR3 of the variable region of the heavy chain consisting of amino acid sequences SEQ ID NO: 52, SEQ ID NO: 53, and SEQ ID NO: 54, respectively, and CDR1, CDR2, and CDR3 of the variable region of the light chain consisting of amino acid sequences SEQ ID NO: 56, SEQ ID NO: 57, and SEQ ID NO: 58, respectively, was similarly prepared.

[0176] A culture supernatant containing the humanized anti-CAPRIN-1 monoclonal antibody #4 (humanized antibody #4) comprising CDR1, CDR2, and CDR3 of the variable region of the heavy chain consisting of the amino acid sequences SEQ ID NO: 60, SEQ ID NO: 61, and SEQ ID NO: 62, respectively, and CDR1, CDR2, and CDR3 of the variable region of the light chain consisting of the amino acid sequences SEQ ID NO: 64, SEQ ID NO: 65, and SEQ ID NO: 66, respectively, was similarly prepared.

[0177] Culture supernatants containing the following humanized anti-CAPRIN-1 monoclonal antibodies #9 to #41 (humanized antibodies #9 to #41) were prepared in a similar manner.

[0178] Humanized monoclonal antibody #9 (humanized antibody #9) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 68 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 69. Petition 870260047669, dated 05 / 19 / 2026, p. 79 / 272 67 / 116

[0179] The humanized monoclonal antibody #10 (humanized antibody #10) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 70 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 71.

[0180] The humanized monoclonal antibody #11 (humanized antibody #11) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 72 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 73.

[0181] The humanized monoclonal antibody #12 (humanized antibody #12) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 74 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 75.

[0182] Humanized monoclonal antibody #13 (humanized antibody #13) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 76 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 77.

[0183] Humanized monoclonal antibody #14 (humanized antibody #14) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 78 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 79.

[0184] Humanized monoclonal antibody #15 (humanized antibody #15) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ Petition 870260047669, dated 05 / 19 / 2026, p. 80 / 272 68 / 116 ID NO: 80 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 81.

[0185] The humanized monoclonal antibody #16 (humanized antibody #16) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 82 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 83.

[0186] The humanized monoclonal antibody #17 (humanized antibody #17) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 84 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 85.

[0187] The humanized monoclonal antibody #18 (humanized antibody #18) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 86 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 87.

[0188] The humanized monoclonal antibody #19 (humanized antibody #19) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 88 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 89.

[0189] Humanized monoclonal antibody #20 (humanized antibody #20) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 90 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 91.

[0190] Humanized monoclonal antibody #21 (antibody Petition 870260047669, dated 05 / 19 / 2026, pp. 81 / 272 69 / 116 humanized #21) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 92 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 93.

[0191] The humanized monoclonal antibody #22 (humanized antibody #22) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 94 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 95.

[0192] The humanized monoclonal antibody #23 (humanized antibody #23) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 96 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 97.

[0193] The humanized monoclonal antibody #24 (humanized antibody #24) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 98 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 99.

[0194] The humanized monoclonal antibody #25 (humanized antibody #25) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 100 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 101.

[0195] The humanized monoclonal antibody #26 (humanized antibody #26) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 102 and the amino acid sequence of a variable region of the light chain. Petition 870260047669, dated 05 / 19 / 2026, p. 82 / 272 70 / 116 represented by the amino acid sequence SEQ ID NO: 103.

[0196] Humanized monoclonal antibody #27 (humanized antibody #27) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 104 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 105.

[0197] Humanized monoclonal antibody #28 (humanized antibody #28) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 106 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 107.

[0198] The humanized monoclonal antibody #29 (humanized antibody #29) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 108 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 109.

[0199] The humanized monoclonal antibody #30 (humanized antibody #30) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 110 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 111.

[0200] Humanized monoclonal antibody #31 (humanized antibody #31) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 112 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 113.

[0201] Humanized monoclonal antibody #32 (humanized antibody #32) comprising the amino acid sequence of a region Petition 870260047669, dated 05 / 19 / 2026, p. 83 / 272 71 / 116 heavy chain variable represented by the amino acid sequence with SEQ ID NO: 114 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence with SEQ ID NO: 115.

[0202] The humanized monoclonal antibody #33 (humanized antibody #33) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 116 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 117.

[0203] The humanized monoclonal antibody #34 (humanized antibody #34) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 118 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 119.

[0204] The humanized monoclonal antibody #35 (humanized antibody #35) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 120 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 121.

[0205] The humanized monoclonal antibody #36 (humanized antibody #36) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 122 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 123.

[0206] The humanized monoclonal antibody #37 (humanized antibody #37) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 124 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 125. Petition 870260047669, dated 05 / 19 / 2026, p. 84 / 272 72 / 116

[0207] The humanized monoclonal antibody #38 (humanized antibody #38) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 126 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 127.

[0208] The humanized monoclonal antibody #39 (humanized antibody #39) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 128 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 129.

[0209] The humanized monoclonal antibody #40 (humanized antibody #40) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 130 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 131.

[0210] The humanized monoclonal antibody #41 (humanized antibody #41) comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 132 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 133.

[0211] Based on the humanized antibody #1 among these anti-CAPRIN-1 monoclonal antibodies, a nucleotide sequence was designed to express a variable region of the heavy chain comprising CDR1, CDR2, and CDR3, consisting of the amino acid sequences SEQ ID NO: 36, SEQ ID NO: 37, and SEQ ID NO: 38, respectively, and the sequences of the structure region of a human antibody. This nucleotide sequence was inserted into a mammalian expression vector with an insert encoding a constant region of human IgG1 heavy chain where the Petition 870260047669, dated 05 / 19 / 2026, page 85 / 272 73 / 116 serine (Ser) at amino acid position 239 in EU numbering is replaced by aspartic acid (Asp) and isoleucine (Ile) at amino acid position 332 in EU numbering is replaced by glutamic acid (Glu). Furthermore, a nucleotide sequence was designed to express the amino acid sequence of a variable region of the light chain comprising CDR1, CDR2, and CDR3, consisting of the amino acid sequences SEQ ID NOs: 40, SEQ ID NOs: 41, and SEQ ID N: 42, respectively, and the sequences of the structure region of a human antibody, and the nucleotide sequence was inserted into a mammalian expression vector with an insert encoding a constant region of the human IgG1 light chain.These two recombinant expression vectors were transferred into mammalian cells according to a conventional method; and a culture supernatant containing the humanized monoclonal antibody #5 (humanized antibody #5) against CAPRIN-1, composed of a full-length heavy chain amino acid sequence consisting of the variable region of the heavy chain projected above and the constant region of the human IgG1 heavy chain, in which serine (Ser) at amino acid position 239 in EU numbering is replaced by aspartic acid (Asp), and isoleucine (Ile) at amino acid position 332 in EU numbering is replaced by glutamic acid (Glu), and the full-length light chain amino acid sequence consisting of the variable region of the light chain projected above and the constant region of the human light chain, was obtained from the cells.

[0212] A culture supernatant containing the humanized anti-CAPRIN-1 monoclonal antibody #6 (humanized antibody #6) comprising the amino acid sequence of the variable region of the heavy chain and the amino acid sequence of the variable region of the light chain of the humanized antibody #2 produced above was prepared in a similar manner.

[0213] A culture supernatant containing the antibody Petition 870260047669, dated 05 / 19 / 2026, page 86 / 272 74 / 116 humanized monoclonal anti-CAPRIN-1 antibody #7 (humanized antibody #7) comprising the amino acid sequence of the variable region of the heavy chain and the amino acid sequence of the variable region of the light chain of the humanized antibody #3 produced above was prepared in a similar manner.

[0214] A culture supernatant containing the humanized anti-CAPRIN-1 monoclonal antibody #8 (humanized antibody #8) comprising the amino acid sequence of the variable region of the heavy chain and the amino acid sequence of the variable region of the light chain of the humanized antibody #4 produced above was prepared in a similar manner.

[0215] The culture supernatants containing each of the humanized anti-CAPRIN-1 antibodies #42 to #74 (humanized antibodies #42 to #74) comprising the amino acid sequence of the variable region of the heavy chain and the amino acid sequence of the variable region of the light chain of each of the humanized antibodies #9 to #41 produced above were prepared in a similar manner.

[0216] The culture supernatants obtained, each containing the humanized anti-CAPRIN-1 monoclonal antibodies #1 to #74, were purified using Hitrap Sepharose Frap Protein A (GE Healthcare) according to a conventional method. The buffer was replaced with PBS (-). The resulting solution was filtered through a 0.22 µm filter (Merck Millipore Corp.) for the preparation of the humanized antibodies. Example 3 Preparation of the anti-CAPRIN-1 Antibody Conjugate and Immune Activator

[0217] Conjugates of the polyclonal anti-CAPRIN-1 antibodies #1 to #6 described in Example 1 with resiquimod, an immune activator, were prepared using maleimidocaproyl-valine-citrulline-p-aminobenzyloxycarbonyl (MC-val-Cit-PAB-PNP) as a ligand. The preparation of these conjugates was carried out with reference to the method described in Petition 870260047669, dated 05 / 19 / 2026, page 87 / 272 75 / 116 publication WO 2014 / 012479.

[0218] 20 mg / mL of the anti-CAPRIN-1 #0 polyclonal antibody described in Example 1 dissolved in PBS (-) was subjected to buffer replacement with a solution of 500 mM sodium borate and 500 mM sodium chloride (pH 8.0). After incubating the antibody solution at 37°C for 30 minutes with 100 mM dithiothreitol (DTT), the buffer was replaced with a PBS solution () containing 1 mM diethylenetriaminepentaacetic acid (DTPA) using Sephadex G25, and the resulting solution was cooled on ice for the preparation of the reduced anti-CAPRIN-1 #0 polyclonal antibody.

[0219] The amount of thiol per antibody molecule (thiol / antibody ratio) was determined by reacting the antibody with DTNB and measuring the absorbance at 412 nm and the absorbance at 280 nm.

[0220] Resiquimod (Enzo Life Sciences, Inc.) and MC-Val-CitPABC-PNP (Medchem Express) were mixed in DMSO to enable the amino group of resiquimod to react with the benzyloxycarbonyl of MC-ValCit-PABC-PNP, thus preparing a solution of resiquimod bound to MC-Val-Cit-PAB which was then added to the reduced anti-CAPRIN-1 polyclonal antibody #1 prepared above for its reaction. After the reaction, an excess amount of maleimide was added to terminate the reaction, thus preparing a solution containing a conjugate of the anti-CAPRIN-1 polyclonal antibody #1 described in Example 1 with resiquimod. The conjugate obtained was concentrated by ultrafiltration and desalted using Sephadex G25 in a PBS (-) solution. The resulting sample was sterilized by filtration through a 0.22 µm filter to prepare a solution containing the anti-CAPRIN-1 polyclonal antibody conjugate #1 and resiquimod (Conjugate 1).

[0221] A solution containing a polyclonal antibody conjugate of anti-CAPRIN-1 #2 and resiquimod (Conjugate 2), a solution of a Petition 870260047669, dated 05 / 19 / 2026, pp. 88 / 272 76 / 116 anti-CAPRIN-1 polyclonal antibody conjugate #3 and resiquimod (Conjugate 3), a solution of an anti-CAPRIN-1 polyclonal antibody conjugate #4 and resiquimod (Conjugate 4), a solution of an anti-CAPRIN-1 polyclonal antibody conjugate #5 and resiquimod (Conjugate 5), and a solution of an anti-CAPRIN-1 polyclonal antibody conjugate #6 and resiquimod (Conjugate 6) were prepared in the same manner as described above.

[0222] As with the rabbit control antibody described in Example 1 that is not reactive with the CAPRIN-1 protein, a solution containing a conjugate of the rabbit control antibody and resiquimod (control conjugate 1) was also prepared in the same manner as described above.

[0223] A solution containing a humanized antibody conjugate #1, which is an anti-CAPRIN-1 monoclonal antibody described in Example 2, with the resiquimod immune activator (Conjugate 7) was prepared using humanized antibody #1 in the same manner as described above.

[0224] A solution containing a humanized antibody conjugate #2, which is an anti-CAPRIN-1 antibody described in Example 2, with the resiquimod immune activator (Conjugate 8), was prepared using humanized antibody #2 in the same manner.

[0225] A solution containing a humanized antibody conjugate #3 described in Example 2 with the resiquimod immune activator (conjugate 9); a solution containing a humanized antibody conjugate #4 with the resiquimod immune activator (conjugate 10); a solution containing a humanized antibody conjugate #5 with the resiquimod immune activator (conjugate 11); a solution containing a humanized antibody conjugate #6 with the resiquimod immune activator (conjugate 12); a solution containing a humanized antibody conjugate #7 with the resiquimod immune activator (conjugate 13); a solution containing a Petition 870260047669, dated 05 / 19 / 2026, page 89 / 272 77 / 116 humanized antibody conjugate #8 with resiquimod immune activator (Conjugate 14); and solutions containing humanized antibody conjugates #9 to #74 with resiquimod immune activator (Conjugates 45 to 110), each was prepared as described above.

[0226] The prepared solutions containing Conjugates 1 to 14, Conjugates 45 to 110 and Control Conjugate 1 were each filtered through a 0.22 pm filter (Merck Millipore Corp.) for the preparation of the conjugates. Example 4 Preparation of the anti-CAPRIN-1 Antibody Conjugate and Immune Activator

[0227] The conjugates of the anti-CAPRIN-1 polyclonal antibodies described in Example 1 with an immune activator were prepared using the following method. 1-(2(2-aminoethoxy)-2-methylpropyl)-2-(ethoxymethyl)-1Himidazo[4,5-c]quinolin-4-amine, a resiquimod derivative produced by homologation of two carbons from the tertiary hydroxy group of resiquimod and the addition of an amino group to it, was prepared as an immune activator by synthesis, according to a common method.

[0228] Specifically, dry acetonitrile, triethylamine, and trityl chloride were added to resiquimod and reacted in an argon atmosphere. After the reaction, the residue was purified by silica gel column chromatography. The purified product was dissolved in dehydrated DMF and reacted with the added 2,2-dioxide of 3-Boc-1,2,3-oxatiazolidine. The aqueous phase was subjected to extraction with ethyl acetate, according to a common method. The resulting organic phase was then purified by column chromatography for the preparation of the aforementioned resiquimod derivative.

[0229] Next, the following procedure was performed with reference to the method described in J. Med. Chem. (2008) 51, 6.916-6.926 in order to combine the obtained resiquimod derivative with 4-(N-maleimidomethyl)cycloPetition 870260047669, dated 19 / 05 / 2026, page 90 / 272 78 / 116 succinimidyl hexane-1-carboxylate (SMCC), as ligand.

[0230] The resiquimod derivative was dissolved in dehydrated dichloromethane in an argon atmosphere. Diisopropylethylamine and SMCC were added to the solution. The mixture was allowed to react at room temperature for 2 hours. The reaction mixture was purified to obtain a resiquimod condensate with SMCC.

[0231] A conjugate of resiquimod condensate with SMCC ligand and anti-CAPRIN-1 antibody was prepared according to a common method with reference to the methods described in US patent 8,951,528 and JIMD Reports-Case and Research Reports, 2012 / 5.

[0232] Specifically, for the anti-CAPRIN-1 polyclonal antibody #1 dissolved in a phosphate buffer, N-succinimidyl S-acetylthioacetate (SATA) (Thermo Fischer Scientific, Inc.) dissolved in a molar mass of DMSO 10 times that of the antibody was added and reacted at room temperature for 30 minutes at pH 8. Then, the buffer was replaced with a phosphate buffer containing 10 mM EDTA using a desalting column (Thermo Fischer Scientific, Inc.) to obtain a solution containing the anti-CAPRIN-1 polyclonal antibody #1 bound to SATA. To the solution, a phosphate buffer containing 0.5 M hydroxylamine and 25 mM EDTA at a volume of 10% relative to the solution was added, and the mixture was deacetylated by reaction at room temperature for 2 hours.The buffer in the solution containing the anti-CAPRIN-1 polyclonal antibody #1 bound to deacetylated SATA was replaced with a phosphate buffer using a desalting column, as described above, for the preparation of a solution containing an anti-CAPRIN-1 antibody added to the thiol group.

[0233] The condensate prepared above, dissolved in a molar mass of DMSO 10 to 50 times that of this antibody, was added to the solution and the mixture was reacted at room temperature for 1 hour. After Petition 870260047669, dated 05 / 19 / 2026, pp. 91 / 272 79 / 116 of the reaction, the buffer was replaced with a PBS (-) solution using a desalting column, and the resulting solution was concentrated using an ultrafiltration column and sterilized by filtration through a 0.2 µm filter to obtain a solution containing a polyclonal antiCAPRIN-1 antibody conjugate described in Example 1 with the resiquimod derivative (Conjugate 15).

[0234] Similarly to the above, a solution containing an anti-CAPRIN-1 polyclonal antibody conjugate #2 with the resiquimod derivative (Conjugate 16), a solution containing an anti-CAPRIN-1 polyclonal antibody conjugate #3 with the immune activator (Conjugate 17), a solution containing an anti-CAPRIN-1 polyclonal antibody conjugate #4 with the immune activator (Conjugate 18), a solution containing an anti-CAPRIN-1 polyclonal antibody conjugate #5 with the immune activator (Conjugate 19), and a solution containing an anti-CAPRIN-1 polyclonal antibody conjugate #6 with the immune activator (Conjugate 20) were prepared.

[0235] As for the rabbit control antibody described in Example 1 which is non-reactive with the CAPRIN-1 protein, a solution containing a conjugate (Control Conjugate 2) was also prepared in the same manner as described above using the rabbit control antibody.

[0236] A solution containing a humanized antibody conjugate #1, which is one of the anti-CAPRIN-1 monoclonal antibodies described in Example 2, with the resiquimod derivative (Conjugate 21) was prepared in the same manner as described above.

[0237] A solution containing a humanized antibody conjugate #2, which is one of the anti-CAPRIN-1 antibodies described in Example 2, with the resiquimod derivative (Conjugate 22) was obtained in the same manner.

[0238] Similarly, as described above, a solution Petition 870260047669, dated 05 / 19 / 2026, page 92 / 272 80 / 116 containing a humanized antibody conjugate #3, which is an anti-CAPRIN-1 antibody described in Example 2, with the immune activator (Conjugate 23); a solution containing a humanized antibody conjugate #4 with the immune activator (Conjugate 24); a solution containing a humanized antibody conjugate #5 with the immune activator (Conjugate 25); a solution containing a humanized antibody conjugate #6 with the immune activator (Conjugate 26); a solution containing a humanized antibody conjugate #7 with the immune activator (Conjugate 27); and a solution containing a humanized antibody conjugate #8 with the immune activator (Conjugate 28) were prepared.

[0239] Similarly to above, solutions containing the humanized antibody conjugates #9 to #74 with the immune activator (Conjugates 111 to 176) were each prepared.

[0240] The prepared solutions containing Conjugates 15 to 28, Conjugates 111 to 176 and Control Conjugate 2 were each filtered through a 0.22 pm filter (Merck Millipore Corp.) for the preparation of the conjugates. Example 5 Specific Reactivity of the Conjugate with the CAPRIN-1 Protein and the Cancer Cell Expressing CAPRIN-1

[0241] Conjugates 1 to 14 and Conjugates 45 to 110 prepared in Example 3 and Conjugates 15 to 28 and Conjugates 111 to 176 prepared in Example 4 were analyzed for their specific reactivity with a CAPRIN-1 protein and their reactivity with the cell membrane surface of human cancer cells and mouse cancer cells expressing a CAPRIN-1 protein.

[0242] Specific reactivity with CAPRIN-1 protein was determined by ELISA. A 1 pg / mL CAPRIN-1 protein solution was Petition 870260047669, dated 05 / 19 / 2026, page 93 / 272 Solution 81 / 116 was added at 100 pL / well to a 96-well plate, and the plate was left to stand at 4°C for 18 hours. Each well was washed with PBS-T three times. Then, a 0.5% bovine serum albumin (BSA) solution was added at 400 pL / well, and the plate was left to stand at room temperature for 3 hours. The solution was removed, and the wells were washed with 400 pL / well of PBS-T three times. Next, each of the solutions containing Conjugates 1 to 6, Conjugates 15 to 20, Control Conjugate 1, and Control Conjugate 2 was added at 100 pL / well, and the plate was left to stand at room temperature for 2 hours. Each well was washed with PBS-T three times. Next, an HRP-labeled anti-rabbit antibody diluted 5,000 times with PBS was added at 100 pL / well and left to stand at room temperature for 1 hour. Each well was washed with PBS-T three times.Next, a TMB substrate solution was added at 100 pL / well and left to stand for 15 to 30 minutes for the chromogenic reaction. After color development, the reaction was terminated by adding 1 N sulfuric acid at 100 pL / well, and absorbance values ​​at 450 nm and 595 nm were measured using an absorption spectrometer. As a result, Conjugates 1 to 6 and Conjugates 15 to 20 exhibited a higher absorbance value than Control Conjugates 1 and 2, which were used as negative controls, and were found to react specifically with the CAPRIN-1 protein.

[0243] Next, the reactivity with the cell membrane surface of cancer cells expressing CAPRIN-1 was verified by flow cytometry. Human breast cancer cells BT-474 (from ATCC) or mouse breast cancer cells 4T1 (from ATCC) were centrifuged in 1.5 mL microcentrifuge tubes (2 x 10⁵ cells per tube). 100 µL of solutions containing each of Conjugates 1 to 6, Conjugates 15 to 20, Control Conjugate 1, and Control Conjugate 2, Petition 870260047669, dated 05 / 19 / 2026, page 94 / 272 82 / 116 cells were then added to separate tubes. The tube was left on ice for 1 hour. After washing with PBS, Alexa 488 (H+L)-labeled anti-rabbit IgG diluted 100 times with PBS (-) containing 0.5% FBS (0.5% FBS-PBS (-)), the tube was left to stand on ice for 1 hour. After washing with 0.5% FBS-PBS (-), the cells were suspended in 0.2 pg / mL propidium iodide and 0.5% FBS-PBS (-) and the fluorescence intensity was measured using FACSVerse™ (Becton, Dickinson and Company). As a result, it was discovered that Conjugates 1 to 6 and Conjugates 15 to 20, which were conjugates of anti-CAPRIN-1 polyclonal antibodies and the immune activator, exhibited a higher fluorescence intensity than that of Control 1 and Control 2 as negative controls, i.e., to react strongly with the cell surface of human BT474 cancer cells and 4T1 mouse cancer cells expressing CAPRIN-1.

[0244] The reactivity of the conjugates with the following human cancer cells and mouse cancer cells was similarly verified: breast cancer cells (BT-474), colorectal cancer cells (HT29), lung cancer cells (QG56 and H1650), stomach cancer cells (NCI-N87), uterine cancer cells (HEC-1-A), prostate cancer cells (22Rv1), pancreatic cancer cells (Panc10,5), liver cancer cells (Hep3B), ovarian cancer cells (SKOV3), kidney cancer cells (Caki-2), brain tumor cells (U-87MG), bladder cancer cells (T24), stomach cancer cells (OE33), leukemia cells (OCI-AML5), lymphoma cells (Ramos), gallbladder cancer cells (TGBC14TKB), fibrosarcoma cells (HT-1080) and melanoma cells (G361), which are human cancer cells that express the CAPRIN-1 gene;and mouse kidney cancer cells (Renca) and mouse breast cancer cells (4T1), which are cancer cells of; Petition 870260047669, dated 05 / 19 / 2026, page 95 / 272 83 / 116 mice expressing the CAPRIN-1 gene. As a result of the verification, Conjugates 1 to 6 and Conjugates 15 to 20, which were the conjugates of anti-CAPRIN-1 antibodies and the immune activator, exhibited stronger fluorescence intensities for all cancer cells than those of Control Conjugate 1 and Control Conjugate 2 as negative controls and, consequently, showed a strong reaction with the cell membrane surface of the above cancer cells expressing CAPRIN-1.

[0245] In addition, the anti-CAPRIN-1 polyclonal antibodies #1 to #6 prepared in Example 1 that are not conjugated with the immune activator were tested in a similar manner. As a result of the analysis of their reactivity with the above cancer cells expressing CAPRIN-1 by flow cytometry, these antibodies exhibited fluorescence intensities equivalent to those of Conjugates 1 to 6 and Conjugates 15 to 20.

[0246] Next, Conjugates 7 to 14 and Conjugates 45 to 110, which were conjugates of anti-CAPRIN-1 monoclonal antibodies with the immune activator prepared in Example 3, and Conjugates 21 to 28 and Conjugates 111 to 176 prepared in Example 4 were analyzed for their specific reactivity with the CAPRIN-1 protein and their reactivity with the cell membrane surface of human cancer cells and mouse cancer cells expressing CAPRIN-1, in a similar manner as above. As a result, Conjugates 7 to 14 and Conjugates 21 to 28 exhibited significantly higher absorbance values ​​than a negative control with added PBS (-) and, therefore, showed specific reaction with the CAPRIN-1 protein.

[0247] Conjugates 7 to 14, 45 to 110, 21 to 28, and 111 to 176 were further evaluated for their reactivity with the cell membrane surface of cancer cells expressing the CAPRIN-1 protein. As a result, these conjugates Petition 870260047669, dated 05 / 19 / 2026, page 96 / 272 84 / 116 exhibited significantly more intense reactivity than that of a conjugate of the immune activator and non-reactive human IgG with the CAPRIN1 protein, and also exhibited intense reactivity equivalent to that of the anti-CAPRIN-1 monoclonal antibodies #1 to #74 described in Example 2 that are not conjugated with the immune activator.

[0248] These results demonstrated that the anti-CAPRIN-1 antibody conjugates and the immune activator prepared above (Conjugates 7 to 14, Conjugates 45 to 110, Conjugates 21 to 28 and Conjugates 111 to 176) specifically bind to the CAPRIN-1 protein and the cell membrane surface of CAPRIN-1 expressing cancer cells. Example 6 Antitumor Effect of Conjugate 1

[0249] Next, Conjugates 1 to 6 and Conjugates 15 to 20 prepared using the anti-CAPRIN-1 polyclonal antibodies #1 to #6 and Conjugates 7 to 14 and Conjugates 21 to 28 prepared using the anti-CAPRIN-1 monoclonal antibodies in Examples 3 and 4 were evaluated for their in vivo antitumor effects in cancer-bearing mice.

[0250] Specifically, the conjugates of the present invention were examined for their antitumor effect using NODSCID mice into which human-derived cancer cells expressing the CAPRIN-1 protein were transplanted. Human breast cancer cells BT474 were mixed with Matrigel (Sigma-Aldrich Corp.) and transplanted subcutaneously at 107 cells / mouse into mice, which were then cultured until the tumor became 180 mm3 or greater to prepare cancer-bearing mice. BT474 expresses the CAPRIN-1 protein on the cell membrane surface. As shown in Example 5, Conjugates 1 to 6 and Conjugates 15 to 20 prepared using the Petition 870260047669, dated 05 / 19 / 2026, page 97 / 272 85 / 116 polyclonal antibodies #1 to #6 anti-CAPRIN-1 and Conjugates 7 to 14 and Conjugates 21 to 28 prepared using monoclonal anti-CAPRIN-1 antibodies specifically bind to the cell membrane surface. Conjugates 1 to 28 were each administered at 10 mg / kg into the tail veins of 10 cancer-bearing mice.

[0251] A solution containing a trastuzumab and resiquimod conjugate was prepared using the method described in Example 3 and administered as a comparative control in the same quantity as above to cancer-bearing mice. BT474 expresses the HER2 protein, which is a target antigen of trastuzumab, on the cell membrane surface. The trastuzumab and resiquimod conjugate specifically binds to BT474. Administration to cancer-bearing mice was performed once a week.

[0252] PBS (-) was administered to cancer-bearing mice as a negative control.

[0253] The tumor sizes of cancer-bearing mice after administration were measured using calipers over time, and tumor volumes were calculated according to a common method based on the expression: (Length of the major axis of the tumor) x (Length of the minor axis of the tumor)2 x 0.5. As a result of the evaluation, all mice that received Conjugates 1 to 6 prepared in Example 3 and Conjugates 15 to 20 prepared in Example 4 had less than 37% of the tumor volumes 50 days after the start of administration compared to the tumor volume of the negative control (100%). All mice that received Conjugates 7 to 14 and Conjugates 21 to 28 had less than 15% of the tumor volumes. Cancer growth in mice that received Conjugates 11 to 14 and Conjugates 25 to 28 was suppressed earlier compared to... Petition 870260047669, dated 05 / 19 / 2026, pp. 98 / 272 86 / 116 cancers were observed in mice that received Conjugates 7 to 10 and Conjugates 21 to 24. As a result of a similar evaluation of the in vivo antitumor effects of Conjugates 45 to 176 in cancer-bearing mice, all mice had less than 20% of the tumor volumes.

[0254] On the other hand, the tumor volume of mice that received the solution containing the trastuzumab conjugate and resiquimod as a comparative control was 54% compared to the negative control.

[0255] These evaluation results demonstrated that Conjugates 1 to 28 and Conjugates 45 to 176 prepared in Examples 3 and 4 using antibodies against CAPRIN-1 exert a significantly stronger antitumor effect than that of the negative control. These results also demonstrated that Conjugates 1 to 28 and Conjugates 45 to 176 have a significantly stronger antitumor effect than that of the trastuzumab and resiquimod conjugate prepared as a comparative control. Example 7 Antitumor Effect of Conjugate 2

[0256] The anti-CAPRIN-1 antibody and immune activator conjugates (Conjugates 1 to 28) prepared in Examples 3 and 4 were evaluated for their antitumor effects in vivo in cancer-bearing mice.

[0257] Specifically, the conjugates of the present invention were examined for their antitumor effect using Balb / c nude mice into which human-derived cancer cells expressing CAPRIN-1 were transplanted. Human H1650 lung cancer cells were transplanted subcutaneously into the ventral regions of the mice, which were then cultured until the tumor reached 180 mm3. Petition 870260047669, dated 05 / 19 / 2026, page 99 / 272 87 / 116 or higher to prepare cancer-bearing mice. H1650 lung cancer cells express the CAPRIN-1 protein on the cell membrane surface. As shown in Example 5, Conjugates 1 to 28 specifically bind to CAPRIN-1 on the cell membrane surface of H1650 lung cancer cells. Conjugates 1 to 14 prepared in Example 3 and Conjugates 15 to 28 prepared in Example 4 were each administered at 10 mg / kg into the tail veins of 10 cancer-bearing mice.

[0258] A solution containing a conjugate of cetuximab and resiquimod was prepared using the method described in Example 3 and administered as a comparative control in the same quantity as above to cancer-bearing mice. Administration was performed once a week, for a total of three times.

[0259] PBS (-) was administered to cancer-bearing mice as a negative control.

[0260] The tumor sizes of cancer-bearing mice after administration were measured using calipers over time, and tumor volumes were calculated according to a common method based on the expression: (Length of the major axis of the tumor) x (Length of the minor axis of the tumor)2 x 0.5. As a result, mice that received Conjugates 1 to 6 and Conjugates 15 to 20 had less than 22% of the tumor volumes 25 days after the start of administration, compared to the tumor volume of the negative control (100%). All mice that received Conjugates 7 to 14 and Conjugates 21 to 28 had less than 12% of the tumor volumes. Cancer growth in mice that received Conjugates 11 to 14 and Conjugates 25 to 28 was suppressed earlier compared to cancers in mice that received Conjugates 25 to 28. Petition 870260047669, dated 05 / 19 / 2026, pp. 100 / 272 88 / 116 from 7 to 10 and Conjugates from 21 to 24. As a result of similar evaluation of the in vivo antitumor effects of Conjugates from 45 to 176 in cancer-bearing mice, the mice had less than 16% tumor volumes.

[0261] On the other hand, the tumor volume of mice that received the solution containing the cetuximab and resiquimod conjugate as a comparative control was 32% compared to the negative control.

[0262] These evaluation results demonstrated that Conjugates 1 to 28 and Conjugates 45 to 176 exert a significantly more intense antitumor effect than the negative control. These results also demonstrated that Conjugates 1 to 28 and Conjugates 45 to 176 have a significantly more intense antitumor effect than the cetuximab and resiquimod conjugate as a comparative control. Example 8 Preparation of a Chimeric Monoclonal Antibody Conjugate against Mouse CAPRIN-1 and an Immune Activator

[0263] Chimeric mouse antibodies composed of a heavy chain comprising the variable region of the heavy chain of each anti-CAPRIN-1 monoclonal antibody and the constant region of the mouse IgG heavy chain, and a light chain comprising the variable region of the light chain of the anti-CAPRIN-1 monoclonal antibody and the constant region of the mouse IgG light chain were prepared, and then antibody conjugates with the immune activator resiquimod were prepared in the same manner as in Example 3. In addition, chimeric mouse antibodies were prepared, and then antibody conjugates with the antibodies with the resiquimod derivative were prepared in the same manner as in Example 4. Petition 870260047669, dated 05 / 19 / 2026, pp. 101 / 272 89 / 116

[0264] Specifically, the following antibodies were used in this Example as chimeric mouse antibodies comprising the variable light chain regions of anti-CAPRIN-1 monoclonal antibodies and the constant light chain region of mouse IgG.

[0265] The monoclonal antibody against CAPRIN-1 described in publication WO 2011 / 096528, wherein the antibody comprises CDR1, CDR2 and CDR3 of the variable region of the heavy chain consisting of the amino acid sequences of SEQ ID NO: 36, SEQ ID NO: 37 and SEQ ID NO: 38, respectively, and CDR1, CDR2 and CDR3 of the variable region of the light chain consisting of the amino acid sequences of SEQ ID NO: 40, SEQ ID NO: 41 and SEQ ID NO: 42, respectively, and wherein the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by SEQ ID NO: 39 comprising the CDR1, CDR2 and CDR3 mentioned above of the variable region of the heavy chain and the amino acid sequence of a variable region of the light chain represented by SEQ ID NO: 43 comprising the CDR1, CDR2 and CDR3 mentioned above of the variable region of the light chain.

[0266] The monoclonal antibody against CAPRIN-1 described in publication WO 2015 / 020212, wherein the antibody comprises CDR1, CDR2 and CDR3 of the variable region of the heavy chain consisting of the amino acid sequences of SEQ ID NO: 44, SEQ ID NO: 45 and SEQ ID NO: 46, respectively, and CDR1, CDR2 and CDR3 of the variable region of the light chain consisting of the amino acid sequences of SEQ ID NO: 48, SEQ ID NO: 49 and SEQ ID NO: 50, respectively, and wherein the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by SEQ ID NO: 47 comprising the aforementioned CDR1, CDR2 and CDR3 of the variable region of the heavy chain and the amino acid sequence of a variable region of the light chain represented by SEQ ID NO: 51 which Petition 870260047669, dated 05 / 19 / 2026, pp. 102 / 272 90 / 116 comprises the CDR1, CDR2 and CDR3 mentioned above from the variable region of the light chain.

[0267] The monoclonal antibody against CAPRIN-1 described in publication WO 2011 / 096519, wherein the antibody comprises CDR1, CDR2 and CDR3 of the variable region of the heavy chain consisting of the amino acid sequences of SEQ ID NO: 52, SEQ ID NO: 53 and SEQ ID NO: 54, respectively, and CDR1, CDR2 and CDR3 of the variable region of the light chain consisting of the amino acid sequences of SEQ ID NO: 56, SEQ ID NO: 57 and SEQ ID NO: 58, respectively, and wherein the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by SEQ ID NO: 55 comprising the CDR1, CDR2 and CDR3 mentioned above of the variable region of the heavy chain and the amino acid sequence of a variable region of the light chain represented by SEQ ID NO: 59 comprising the CDR1, CDR2 and CDR3 mentioned above of the variable region of the light chain.

[0268] The monoclonal antibody against CAPRIN-1 described in publication WO 2013 / 125654, wherein the antibody comprises CDR1, CDR2 and CDR3 of the variable region of the heavy chain consisting of the amino acid sequences of SEQ ID NO: 60, SEQ ID NO: 61 and SEQ ID NO: 62, respectively, and CDR1, CDR2 and CDR3 of the variable region of the light chain consisting of the amino acid sequences of SEQ ID NO: 64, SEQ ID NO: 65 and SEQ ID NO: 66, respectively, and wherein the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by SEQ ID NO: 63 comprising the aforementioned CDR1, CDR2 and CDR3 of the variable region of the heavy chain and the amino acid sequence of a variable region of the light chain represented by SEQ ID NO: 67 comprising the aforementioned CDR1, CDR2 and CDR3 of the variable region of the light chain. Petition 870260047669, dated 05 / 19 / 2026, page 103 / 272 91 / 116

[0269] The monoclonal antibody against CAPRIN-1 described in publication WO 2011 / 096517, the antibody comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 68 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 69.

[0270] The monoclonal antibody against CAPRIN-1 described in publication WO 2011 / 096528, wherein the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 70 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 71; the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 72 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 73; the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 74 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 75;The antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 76 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 77; or the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 78 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 79.

[0271] The monoclonal antibody against CAPRIN-1 described in Petition 870260047669, dated 05 / 19 / 2026, page 104 / 272 92 / 116 publication WO 2011 / 096533, wherein the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 80 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 81, or the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 82 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 83.

[0272] The monoclonal antibody against CAPRIN-1 described in publication WO 2011 / 096534, wherein the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 84 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 85, or the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 86 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 87.

[0273] The monoclonal antibody against CAPRIN-1 described in publication WO 2010 / 016526, wherein the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 88 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 89; the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 90 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 91; the Petition 870260047669, dated 05 / 19 / 2026, page 105 / 272 93 / 116 antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 92 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 93; the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 94 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 95; the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 96 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 97;The antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence SEQ ID NO: 98 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence SEQ ID NO: 99; or the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence SEQ ID NO: 100 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence SEQ ID NO: 101.

[0274] The monoclonal antibody against CAPRIN-1 described in publication WO 2013 / 018894, wherein the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 102 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 103, or the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 104 and the amino acid sequence Petition 870260047669, dated 05 / 19 / 2026, page 106 / 272 94 / 116 of a variable region of the light chain represented by the amino acid sequence SEQ ID NO: 105.

[0275] The monoclonal antibody against CAPRIN-1 described in publication WO 2013 / 018892, the antibody comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 106 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 107.

[0276] The monoclonal antibody against CAPRIN-1 described in publication WO 2013 / 018891, the antibody comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 108 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 109.

[0277] The monoclonal antibody against CAPRIN-1 described in publication WO 2013 / 018889, the antibody comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 110 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 111.

[0278] The monoclonal antibody against CAPRIN-1 described in publication WO 2013 / 018883, the antibody comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 112 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 113.

[0279] The monoclonal antibody against CAPRIN-1 described in publication WO 2013 / 125636, the antibody comprising the sequence of Petition 870260047669, dated 05 / 19 / 2026, p. 107 / 272 95 / 116 amino acids from a variable region of the heavy chain represented by the amino acid sequence SEQ ID NO: 114 and the amino acid sequence from a variable region of the light chain represented by the amino acid sequence SEQ ID NO: 115.

[0280] The monoclonal antibody against CAPRIN-1 described in publication WO 2013 / 125654, wherein the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 116 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 117, or the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 118 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 119.

[0281] The monoclonal antibody against CAPRIN-1 described in publication WO 2013 / 125630, the antibody comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 120 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 121.

[0282] The monoclonal antibody against CAPRIN-1 described in publication WO 2015 / 020212, wherein the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 122 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 123; the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 124 and the amino acid sequence Petition 870260047669, dated 05 / 19 / 2026, pp. 108 / 27296 / 116 of a variable region of the light chain represented by the amino acid sequence SEQ ID NO: 125; the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence SEQ ID NO: 126 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence SEQ ID NO: 127; the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence SEQ ID NO: 128 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence SEQ ID NO: 129; the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence SEQ ID NO: 130 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence SEQ ID NO: 131;or the antibody comprises the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 132 and the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 133.;

[0283] Chimeric mouse antibodies were prepared using the following method.

[0284] Specifically, an amplification fragment of a gene encoding a variable region of the heavy chain comprising the amino acid sequence represented by SEQ ID NO: 39, according to the present invention, was treated at both ends with restriction enzymes, then purified and inserted into a vector comprising insertions of a human antibody-derived leader sequence and the mouse IgG heavy chain constant region, according to a common method. Furthermore, an amplification fragment of a gene encoding a region Petition 870260047669, dated 05 / 19 / 2026, p. 109 / 272 The 97 / 116 variable of the light chain comprising the amino acid sequence represented by SEQ ID NO: 43 was treated at both ends with restriction enzymes, then purified and inserted into a vector that already includes insertions of a human antibody-derived leader sequence and the mouse IgG light chain constant region, according to a common method.

[0285] Next, the recombinant vector having a gene insertion of the variable region of the antibody heavy chain against CAPRIN-1, as described above, and the recombinant vector having a gene insertion of the variable region of the antibody light chain, were transferred into mammalian cells, according to a common method and a solution containing the chimeric mouse antibody #1 composed of a heavy chain comprising the variable region of the antibody heavy chain against CAPRIN-1 represented by SEQ ID NO: 39 and the constant region of the mouse IgG heavy chain and the light chain comprising the variable region of the light chain represented by SEQ ID NO: 43 of the antibody against CAPRIN-1 and the constant region of the mouse IgG light chain.

[0286] A solution containing chimeric mouse antibody #2 composed of a heavy chain comprising a variable region of the heavy chain having the amino acid sequence represented by SEQ ID NO: 47 and the constant region of the mouse IgG heavy chain, and a light chain comprising a variable region of the light chain having the amino acid sequence represented by SEQ ID NO: 51 and the constant region of the mouse IgG light chain was prepared in a similar manner.

[0287] A solution containing chimeric mouse antibody #3 composed of a heavy chain comprising a variable region of the heavy chain having the amino acid sequence represented Petition 870260047669, dated 05 / 19 / 2026, page 110 / 272 98 / 116 by SEQ ID NO: 55 and the constant region of mouse IgG heavy chain, and a light chain comprising a variable region of the light chain having the amino acid sequence represented by SEQ ID NO: 59 and the constant region of mouse IgG light chain was prepared in a similar manner.

[0288] A solution containing the chimeric mouse antibody #4 composed of a heavy chain comprising a variable region of the heavy chain comprising the amino acid sequence represented by SEQ ID NO: 63 and the constant region of the mouse IgG heavy chain, and a light chain comprising a variable region of the light chain having the amino acid sequence represented by SEQ ID NO: 67 and the constant region of the mouse IgG light chain was prepared in a similar manner.

[0289] Solutions containing the following chimeric mouse antibodies #5 to #37 were prepared in a similar manner.

[0290] The chimeric mouse antibody #5 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 68 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 69 and the constant region of the mouse IgG light chain.

[0291] The chimeric mouse antibody #6 is composed of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 70 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 71 Petition 870260047669, dated 05 / 19 / 2026, p. 111 / 272 99 / 116 and the constant region of the mouse IgG light chain.

[0292] A solution containing chimeric mouse antibody #7 composed of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 72 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 73 and the constant region of the mouse IgG light chain.

[0293] The chimeric mouse antibody #8 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 74 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 75 and the constant region of the mouse IgG light chain.

[0294] The chimeric mouse antibody #9 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 76 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 77 and the constant region of the mouse IgG light chain.

[0295] The chimeric mouse antibody #10 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 78 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region Petition 870260047669, dated 05 / 19 / 2026, p. 112 / 272 100 / 116 of the light chain represented by the amino acid sequence of SEQ ID NO: 79 and the constant region of the mouse IgG light chain.

[0296] The chimeric mouse antibody #11 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 80 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 81 and the constant region of the mouse IgG light chain.

[0297] The chimeric mouse antibody #12 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 82 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 83 and the constant region of the mouse IgG light chain.

[0298] The chimeric mouse antibody #13 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 84 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 85 and the constant region of the mouse IgG light chain.

[0299] The chimeric mouse antibody #14 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 86 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region Petition 870260047669, dated 05 / 19 / 2026, p. 113 / 272 101 / 116 of the light chain represented by the amino acid sequence of SEQ ID NO: 87 and the constant region of the mouse IgG light chain.

[0300] The chimeric mouse antibody #15 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 88 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 89 and the constant region of the mouse IgG light chain.

[0301] The chimeric mouse antibody #16 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 90 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 91 and the constant region of the mouse IgG light chain.

[0302] The chimeric mouse antibody #17 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 92 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 93 and the constant region of the mouse IgG light chain.

[0303] The chimeric mouse antibody #18 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 94 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region Petition 870260047669, dated 05 / 19 / 2026, p. 114 / 272 102 / 116 of the light chain represented by the amino acid sequence of SEQ ID NO: 95 and the constant region of the mouse IgG light chain.

[0304] The chimeric mouse antibody #19 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 96 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 97 and the constant region of the mouse IgG light chain.

[0305] The chimeric mouse antibody #20 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 98 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 99 and the constant region of the mouse IgG light chain.

[0306] The chimeric mouse antibody #21 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 100 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 101 and the constant region of the mouse IgG light chain.

[0307] The chimeric mouse antibody #22 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 102 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a region Petition 870260047669, dated 05 / 19 / 2026, pp. 115 / 272 103 / 116 light chain variable represented by the amino acid sequence of SEQ ID NO: 103 and the constant region of the mouse IgG light chain.

[0308] The chimeric mouse antibody #23 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 104 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 105 and the constant region of the mouse IgG light chain.

[0309] The chimeric mouse antibody #24 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 106 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 107 and the constant region of the mouse IgG light chain.

[0310] The chimeric mouse antibody #25 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 108 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 109 and the constant region of the mouse IgG light chain.

[0311] The chimeric mouse antibody #26 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 110 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a region Petition 870260047669, dated 05 / 19 / 2026, pp. 116 / 272 104 / 116 light chain variable represented by the amino acid sequence of SEQ ID NO: 111 and the constant region of the mouse IgG light chain.

[0312] The chimeric mouse antibody #27 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 112 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 113 and the constant region of the mouse IgG light chain.

[0313] The chimeric mouse antibody #28 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 114 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 115 and the constant region of the mouse IgG light chain.

[0314] The chimeric mouse antibody #29 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 116 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 117 and the constant region of the mouse IgG light chain.

[0315] The chimeric mouse antibody #30 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 118 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a region Petition 870260047669, dated 05 / 19 / 2026, p. 117 / 272 105 / 116 light chain variable represented by the amino acid sequence of SEQ ID NO: 119 and the constant region of the mouse IgG light chain.

[0316] The chimeric mouse antibody #31 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 120 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 121 and the constant region of the mouse IgG light chain.

[0317] The chimeric mouse antibody #32 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 122 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 123 and the constant region of the mouse IgG light chain.

[0318] The chimeric mouse antibody #33 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 124 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 125 and the constant region of the mouse IgG light chain.

[0319] The chimeric mouse antibody #34 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 126 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a region Petition 870260047669, dated 05 / 19 / 2026, pp. 118 / 272 106 / 116 light chain variable represented by the amino acid sequence of SEQ ID NO: 127 and the constant region of the mouse IgG light chain.

[0320] The chimeric mouse antibody #35 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 128 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 129 and the constant region of the mouse IgG light chain.

[0321] The chimeric mouse antibody #36 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 130 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 131 and the constant region of the mouse IgG light chain.

[0322] The chimeric mouse antibody #37 consists of a heavy chain comprising the amino acid sequence of a variable region of the heavy chain represented by the amino acid sequence of SEQ ID NO: 132 and the constant region of the mouse IgG heavy chain and a light chain comprising the amino acid sequence of a variable region of the light chain represented by the amino acid sequence of SEQ ID NO: 133 and the constant region of the mouse IgG light chain.

[0323] The supernatant of the prepared culture containing each of the chimeric mouse antibodies #1 to #37 was purified according to a conventional method using Sepharose Hitrap FF Protein A (GE Healthcare Japan Corp.). The buffer was replaced with PBS (-) and the resulting solution was filtered through a 0.22 µm filter (Merck Millipore Corp.) for preparation. Petition 870260047669, dated 05 / 19 / 2026, p. 119 / 272 107 / 116 of chimeric mouse antibodies.

[0324] The conjugates with resiquimod were prepared in the same manner as the method described in Example 3 using the chimeric mouse antibodies #1 to #37 prepared above. Solutions containing a chimeric mouse antibody conjugate #1 with the resiquimod immune activator (Conjugate 29), a chimeric mouse antibody conjugate #2 with the resiquimod immune activator (Conjugate 30), a chimeric mouse antibody conjugate #3 with the resiquimod immune activator (Conjugate 31), a chimeric mouse antibody conjugate #4 with the resiquimod immune activator (Conjugate 32), a chimeric mouse antibody conjugate #5 with the resiquimod immune activator (Conjugate 177), a chimeric mouse antibody conjugate #6 with the resiquimod immune activator (Conjugate 178), a chimeric mouse antibody conjugate #7 with the resiquimod immune activator (Conjugate 179),a chimeric mouse antibody conjugate #8 with the resiquimod immune activator (Conjugate 180), a chimeric mouse antibody conjugate #9 (Conjugate 181), a chimeric mouse antibody conjugate #10 with the resiquimod immune activator (Conjugate 182), a chimeric mouse antibody conjugate #11 with the resiquimod immune activator (Conjugate 183), a chimeric mouse antibody conjugate #12 with the resiquimod immune activator (Conjugate 184), a chimeric mouse antibody conjugate #13 with the resiquimod immune activator (Conjugate 185), a chimeric mouse antibody conjugate #14 with the resiquimod immune activator (Conjugate 186), a chimeric mouse antibody conjugate #15 with the resiquimod immune activator (Conjugate 187), a chimeric mouse antibody conjugate #16 with the immune activator resiquimod (Conjugate 188), a chimeric antibody conjugate of, Petition 870260047669, dated 05 / 19 / 2026, pp. 120 / 272 108 / 116 mouse #17 with resiquimod immune activator (Conjugate 189), a chimeric antibody conjugate of mouse #18 with resiquimod immune activator (Conjugate 190), a chimeric antibody conjugate of mouse #19 with resiquimod immune activator (Conjugate 191), a chimeric antibody conjugate of mouse #20 with resiquimod immune activator (Conjugate 192), a chimeric antibody conjugate of mouse #21 with resiquimod immune activator (Conjugate 193), a chimeric antibody conjugate of mouse #22 with resiquimod immune activator (Conjugate 194), a chimeric antibody conjugate of mouse #23 with resiquimod immune activator (Conjugate 195), a chimeric antibody conjugate of mouse #24 with the resiquimod immune activator (Conjugate 196), a chimeric mouse antibody conjugate #25 with resiquimod immune activator (Conjugate 197),a chimeric mouse antibody conjugate #26 with the resiquimod immune activator (Conjugate 198), a chimeric mouse antibody conjugate #27 with the resiquimod immune activator (Conjugate 199), a chimeric mouse antibody conjugate #28 with the resiquimod immune activator (Conjugate 200), a chimeric mouse antibody conjugate #29 with the resiquimod immune activator (Conjugate 201), a chimeric mouse antibody conjugate #30 with the resiquimod immune activator (Conjugate 202), a chimeric mouse antibody conjugate #31 with the resiquimod immune activator (Conjugate 203), a chimeric mouse antibody conjugate #32 with the resiquimod immune activator (Conjugate 204), a chimeric mouse antibody conjugate #33 with the resiquimod immune activator (Conjugate 205), a chimeric mouse antibody conjugate #34 with the resiquimod immune activator (Conjugate 206),a chimeric mouse antibody conjugate #35 with the immune activator resiquimod (Conjugate 207), a Petition 870260047669, dated 05 / 19 / 2026, pp. 121 / 272 A chimeric mouse antibody conjugate #36 with the resiquimod immune activator (Conjugate 208) and a chimeric mouse antibody conjugate #37 with the resiquimod immune activator (Conjugate 209) were prepared.

[0325] In addition, conjugates with the resiquimod derivative were prepared in the same manner as the method described in Example 4 using the chimeric mouse antibodies #1 to #37 prepared above. Solutions containing a chimeric mouse antibody conjugate #1 with the resiquimod derivative (Conjugate 33), a chimeric mouse antibody conjugate #2 with the resiquimod derivative (Conjugate 34), a chimeric mouse antibody conjugate #3 with the resiquimod derivative (Conjugate 34) 35), and a chimeric mouse antibody conjugate #4 with the resiquimod derivative (Conjugate 36) were prepared. Solutions containing the chimeric mouse antibody conjugates #5 to #37 with the resiquimod derivative (Conjugates 210 to 242) were prepared in a similar manner.

[0326] The prepared solutions containing Conjugates 29 to 36, Conjugates 177 to 242 and Control Conjugate 2 were each filtered through a 0.22 pm filter (manufactured by Merck Millipore Corp.) for the preparation of the conjugates.

[0327] Conjugates 29 to 36 and Conjugates 177 to 242 were analyzed for their specific reactivity with the CAPRIN-1 protein in a similar manner to that in Example 5 using prepared solutions containing Conjugates 29 to 36 and Conjugates 177 to 242. As a result, solutions containing Conjugates 29 to 36 and Conjugates 177 to 242 each exhibited specific reactivity with the CAPRIN-1 protein.

[0328] In addition, the conjugates of 29 to 36 and the Petition 870260047669, dated 05 / 19 / 2026, pp. 122 / 272 110 / 116 Conjugates 177 to 242 were analyzed for their reactivity with cancer cells using flow cytometry with cancer cells expressing CAPRIN-1 on the cell membrane surface. As a result, all conjugates exhibited higher fluorescence intensity than the negative control. Furthermore, the conjugates were found to exhibit reactivity equivalent to that of the anti-CAPRIN-1 monoclonal antibodies described in the chimeric mouse antibodies #1 to #37 prepared above, unconjugated with the immune activator. Example 9 Antitumor effect of the chimeric monoclonal antibody conjugate against mouse caprin-1 and an immune activator.

[0329] The chimeric anti-CAPRIN-1 mouse monoclonal antibody conjugates and the immune activator (Conjugates 29 to 36 and Conjugates 177 to 242) prepared in Example 8 were evaluated for their in vivo antitumor effects in cancer-bearing mice.

[0330] Specifically, the conjugates of the present invention were examined for their antitumor effect using Balb / c mice into which mouse-derived cancer cells expressing CAPRIN-1 were transplanted. Mouse breast cancer 4T1 cells were transplanted subcutaneously at a rate of 10⁴ cells / mouse to the ventral regions of mice, which were then cultured until the tumor became 30 mm³ or greater to prepare cancer-bearing mice. As shown in Example 5, breast cancer 4T1 cells are cells that express the CAPRIN1 protein on the cell membrane surface. Solutions containing Conjugates 29 to 36 prepared in Example 8 specifically bind to CAPRIN-1 in Petition 870260047669, dated 05 / 19 / 2026, pp. 123 / 272 111 / 116 cell membrane surface of 4T1 breast cancer cells. Conjugates 29 to 36 prepared in Example 8 were each administered at 8 mg / kg into the tail veins of 10 cancer-bearing mice. Chimeric mouse antibodies #1 to #4 were each administered as a comparative control in the same quantity as above to the cancer-bearing mice. Administration was performed twice weekly for a total of four times. PBS (-) was administered to the cancer-bearing mice for a negative control. The tumor sizes of the cancer-bearing mice after administration were measured using the calipers over time, and the tumor volumes were calculated according to a common method based on the expression: (Tumor major axis length) x (Tumor minor axis length)2 x 0.5.As a result, all mice that received Conjugates 29 to 36 had 0% of the tumor volume 20 days after the start of administration compared to the tumor volume of the negative control (100%). Furthermore, mice that received chimeric mouse antibodies #1 to #4 had only 69% of the tumor volume on average compared to the tumor volume of the negative control mice (100%). These evaluation results demonstrated that resiquimod conjugates and chimeric anti-CAPRIN-1 mouse antibodies (chimeric mouse antibodies) (Conjugates 29 to 32) and the resiquimod derivative conjugates and these antibodies (Conjugates 33 to 36) prepared in Example 8 exert a more intense antitumor effect when compared to the negative control and when administering the anti-CAPRIN-1 antibody alone to cancer-bearing mice.As a result of a similar evaluation of Conjugates 177 to 242 regarding their antitumor effects, all mice that received Conjugates 29 to 36 had 0% of the tumor volume relative to the tumor volume of the... Petition 870260047669, dated 05 / 19 / 2026, pp. 124 / 272 112 / 116 negative control (100%). Mice that received chimeric mouse antibodies #5 to #37 in isolation had 69% of the tumor volume on average compared to the tumor volume of the negative control (100%). Example 10 Antitumor effect of Conjugate 3

[0331] An in vivo antitumor effect in cancer-bearing mice was compared between Conjugates 7 to 14, Conjugates 21 to 28, and Conjugates 45 to 179 prepared in Example 4 using anti-CAPRIN-1 monoclonal antibodies, and a trastuzumab conjugate prepared in the same manner as in Example 4, using the existing anti-cancer drug antibody trastuzumab, or trastuzumab.

[0332] The trastuzumab conjugate is a conjugate prepared in the same manner as in Example 4 using trastuzumab and the immune activator. The trastuzumab conjugate and the immune activator were prepared using the following method.

[0333] With reference to J. Med. Chem. 2008, 51,6.916-6.926, succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC) was condensed with 1-(2(2-aminoethoxy)-2-methylpropyl)-2-(ethoxymethyl)-1Himidazo[4,5-c]quinolin-4-amine, a resiquimod derivative produced by homologation of two carbons from the tertiary hydroxy group of resiquimod and the addition of an amino group to it to obtain a resiquimod condensate bound to SMCC, as the immune activator.

[0334] However, trastuzumab was used in the preparation of the conjugate after removing a formulation composition contained in a solution using an ultrafilter, or just the affinity-purifying trastuzumab using a protein A carrier and adding the trastuzumab to a phosphate buffer. A conjugate of the resiquimod condensate with the SMCC ligand, as described above, and an anti-CAPRIN-1 antibody was prepared. Petition 870260047669, dated 05 / 19 / 2026, pp. 125 / 272 113 / 116 according to a common method with reference to the methods described in US Patent 8,951,528 and JIMD Case and Research Reports, 2012 / 5. Using trastuzumab dissolved in a phosphate buffer, a solution containing trastuzumab added with SATA was obtained in the same manner as in Example 4. This solution was further reacted with the condensate prepared above to prepare a solution containing a trastuzumab conjugate and the resiquimod derivative (Trastuzumab conjugate). The trastuzumab conjugate obtained was verified by flow cytometry to exhibit reactivity with human breast cancer cells used in the evaluation of the antitumor effect.It was further verified by mass spectrometry that the trastuzumab conjugate prepared for comparison, and Conjugates 7 to 14, Conjugates 21 to 28, and Conjugates 45 to 179 prepared in Example 4 using anti-CAPRIN-1 monoclonal antibodies, have comparable numbers of immune activator molecules bound at that site, and the verified conjugates were used in the subsequent evaluation.

[0335] For comparison of the antitumor effect, human breast cancer cells BT474 were mixed with Matrigel (Sigma-Aldrich Corp.) and transplanted subcutaneously at 107 cells / mouse to mice, which were cultured until the tumor became 150 mm3 or greater for the preparation of cancer-bearing mice. BT474 was found to express the CAPRIN-1 protein and HER2, which is a target antigen of trastuzumab, on the cell membrane surface.

[0336] Anti-CAPRIN-1 antibody conjugates (Conjugates 7 to 14, Conjugates 21 to 28, and Conjugates 45 to 179) and the trastuzumab conjugate prepared above were each administered at 10 mg / kg into the tail veins of 10 cancer-bearing mice. Administration was performed twice weekly for a total of 13 times. For comparison, anti-CAPRIN-1 antibodies Petition 870260047669, dated 05 / 19 / 2026, pp. 126 / 272 114 / 116 used in the preparation of the anti-CAPRIN-1 antibody conjugates (Conjugates 7 to 14, Conjugates 21 to 28 and Conjugates 45 to 179) and trastuzumab were administered in the same manner as above. PBS (-) was administered to cancer-bearing mice as a negative control.

[0337] The tumor sizes of cancer-bearing mice after administration were measured using calipers over time, and tumor volumes were calculated according to a common method based on the expression: (Length of the major axis of the tumor) x (Length of the minor axis of the tumor)2 x 0.5. As a result of the evaluation, all mice that received Conjugates 11 and 25 had less than 15% of the tumor volumes 45 days after the start of administration, compared to the tumor volume of the negative control (100%). Mice that received the unconjugated anti-CAPRIN-1 antibodies to be compared had less than 50% of the tumor volume. From these results, it was demonstrated that the conjugation of the immune activator to the anti-CAPRIN-1 antibody intensified the antitumor effect of the antibody by 77%.The intensification rate was calculated based on the expression: 1 - (Tumor volume determined with conjugate / Tumor volume determined with antibody alone) x 100 (%).

[0338] On the other hand, mice that received the trastuzumab conjugate and mice that received the unconjugated trastuzumab to be compared showed tumor volumes of 53% and 74%, respectively, in relation to the tumor volume of the negative control (100%). Therefore, the rate of intensification of the antitumor effect through conjugation of the immune activator to trastuzumab was only less than 29%. Example 11 Preparation of the anti-CAPRIN-1 Antibody Conjugate and Immune Activator and the Antitumor Effect of the Conjugate

[0339] Humanized antibody conjugates #1 to #8 that Petition 870260047669, dated 05 / 19 / 2026, pp. 127 / 272 115 / 116 were the anti-CAPRIN-1 monoclonal antibodies described in Example 2 with an immune activator DSR-6434 (6-amino-2(butylamino)-9-[[6-[2-(dimethylamino)ethoxy]-3pyridinyl]methyl]-7,9-dihydro-8H-purine-8-one) (Conjugates 37 to 44) were prepared. Specifically, a condensate of DSR-6434 with succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC) via the amino group of DSR-6434 was first synthesized, and then solutions containing the humanized antibody conjugates #1 to #8 and the immune activator DSR-6434 (Conjugates 37 to 44) were prepared basically according to the method described in Example 4.

[0340] Each of the prepared solutions containing Conjugates 37 to 44 was filtered through a 0.22 pm filter (Merck Millipore Corp.) for the preparation of the conjugates. The conjugates were analyzed for their specific reactivity with the CAPRIN-1 protein in the same manner as in Example 5. As a result, the solutions containing Conjugates 37 to 44 each exhibited specific reactivity with the CAPRIN-1 protein.

[0341] Conjugates 37 to 44 were further analyzed for their reactivity with cancer cells by flow cytometry using cancer cells expressing the CAPRIN-1 protein on the cell membrane surface. As a result, all conjugates exhibited higher fluorescence intensity than the negative control. It was found that the conjugates exhibit fluorescence intensity similar to that of the antibodies used alone in the conjugates.

[0342] Conjugates 37 to 44 were evaluated for their antitumor effects in cancer-bearing mice. The anti-CAPRIN-1 antibody conjugates (Conjugates 37 to 44) were each administered at 10 mg / kg into the tail veins of 10 cancer-bearing mice in a manner similar to the method described in Example 10. The administration was Petition 870260047669, dated 05 / 19 / 2026, pp. 128 / 272 116 / 116 performed twice a week for a total of 16 times. The anti-CAPRIN-1 antibodies used in the preparation of the conjugates were administered in a similar manner as above. PBS (-) was administered to cancer-bearing mice as a negative control.

[0343] The tumor sizes of cancer-bearing mice after administration were measured using calipers over time, and tumor volumes were calculated according to a common method based on the expression: (Length of the major axis of the tumor) x (Length of the minor axis of the tumor)2x0.5. As a result of the evaluation, all mice that received Conjugates 37 to 44 showed less than 32% of the tumor volumes, 50 days after the start of administration, compared to the tumor volume of the negative control (100%). Mice that received the unconjugated anti-CAPRIN-1 antibodies to be compared had less than 50% of the tumor volume. From these results, the conjugation of the immune activator with the anti-CAPRIN-1 antibody showed to intensify the antitumor effect by more than 35%.The intensification rate was calculated based on the expression: 1 - (Tumor volume determined with the conjugate / Tumor volume determined with the antibody alone) x 100 (%). Petition 870260047669, dated 05 / 19 / 2026, pp. 129 / 272

Claims

1. A CONJUGATE OF AN ANTIBODY or a fragment thereof, linked to an immune activator, characterized in that the antibody or fragment thereof has immunological reactivity with a CAPRIN-1 protein that has an amino acid sequence represented by any SEQ ID NOs of even numbers between SEQ ID NOs: 2 to 30; wherein the antibody or fragment thereof is any of the following from (A) to (M): (A) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 36, 37 and 38 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 40, 41 and 42 (CDR1, CDR2 and CDR3, respectively) and has immunological reactivity with the CAPRIN-1 protein, (B) an antibody or a fragment thereof,comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 44, 45 and 46 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 48, 49 and 50 (CDR1, CDR2 and CDR3, respectively) and has immunological reactivity with the CAPRIN-1 protein, (C) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 52, 53 and 54 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 56, 57 and 58 (CDR1, CDR2 and CDR3, respectively) and has reactivity Petition 870260047669, of 19 / 05 / 2026, page 130 / 272 2 / 8 immunological with the CAPRIN-1 protein, (D) an antibody or a fragment thereof,(E) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 60, 61 and 62 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 64, 65 and 66 (CDR1, CDR2 and CDR3, respectively) and possessing immunological reactivity with the CAPRIN-1 protein, (F) an antibody or a fragment thereof,which comprises a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 176, 177 and 178 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 179, 180 and 181 (CDR1, CDR2 and CDR3, respectively) and has immunological reactivity with the CAPRIN-1 protein, (G) an antibody or a fragment thereof, which comprises a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 182, 183 and 184 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 185, 186 and 187 (CDR1, CDR2 and CDR3, respectively) and has reactivity Petition 870260047669, 05 / 19 / 2026, page 131 / 272 3 / 8 immunological with the CAPRIN-1 protein, (H) an antibody or a fragment thereof,(I) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 188, 189, and 190 (CDR1, CDR2, and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 191, 192, and 193 (CDR1, CDR2, and CDR3, respectively) and possessing immunological reactivity with the CAPRIN-1 protein, (I) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 146, 147, and 148 (CDR1, CDR2, and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 149, 150, and 223 (CDR1, CDR2, and CDR3, respectively) and possessing immunological reactivity with the protein CAPRIN-1, (J) an antibody or a fragment thereof,which comprises a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 272, 273 and 274 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 275, 276 and 277 (CDR1, CDR2 and CDR3, respectively) and has immunological reactivity with the CAPRIN-1 protein, (K) an antibody or a fragment thereof, which comprises a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 290, 291 and 292 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 293, 294 and 295 (CDR1, CDR2 and CDR3, respectively) and has reactivity Petition 870260047669, 05 / 19 / 2026, page 132 / 272 4 / 8 immunological with the CAPRIN-1 protein, (L) an antibody or a fragment thereof,which comprises a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 300, 301 and 302 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 304, 305 and 306 (CDR1, CDR2 and CDR3, respectively) and has immunological reactivity with the CAPRIN-1 protein, and (M) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the complementarity-determining regions of SEQ ID NOs: 134, 135 and 136 (CDR1, CDR2 and CDR3, respectively) and a variable region of the light chain comprising the complementarity-determining regions of SEQ ID NOs: 137, 138 and 139 (CDR1, CDR2 and CDR3, respectively) and has immunological reactivity with the CAPRIN-1 protein; and also in which the immune activator is resiquimod or derivatives thereof.

2. CONJUGATE, according to claim 1, characterized in that the antibody or a fragment thereof has immunological reactivity with a partial polypeptide of the CAPRIN-1 protein, wherein the partial polypeptide has an amino acid sequence represented by any of the following SEQ ID NOs: 31 to 35 and 296 to 299, 308 and 309.

3. CONJUGATE, according to any one of claims 1 to 2, characterized in that the antibody is a monoclonal antibody.

4. CONJUGATE, according to any one of claims 1 to 3, characterized in that the antibody or a fragment thereof is any one of the following from (a) to (e), (g), (k) to (n), (ab), (ae) to (al): (a) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 39 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 43, (b) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 47 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 51, (c) an antibody or a fragment thereof,comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 55 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 59, (d) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 63 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 67, (e) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 68 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 69, (g) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 72 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 73,(k) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 80 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 81; (l) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 82 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 83; (m) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 84 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 85; (n) an antibody or a fragment thereof,comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 86 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 87, (ab) an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 114 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 115, (ae) an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 120 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 121, (af) an antibody or a fragment thereof comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 122 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 123,(ag) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NOs: 124 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NOs: 125, (ah) an antibody or a fragment thereof, comprising Petition 870260047669, dated 19 / 05 / 2026, page 135 / 272 7 / 8 a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 126 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 127, (ai) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NOs: 128 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NOs: 129, (aj) an antibody or a fragment thereof,comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 130 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 131, (ak) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 132 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO: 133 and (al) an antibody or a fragment thereof, comprising a variable region of the heavy chain comprising the amino acid sequence of SEQ ID NO: 303 and a variable region of the light chain comprising the amino acid sequence of SEQ ID NO:

307.

5. CONJUGATE, according to any one of claims 1 to 4, characterized in that the antibody is a human antibody, a humanized antibody, a chimeric antibody or a single-chain antibody.

6. CONJUGATE, according to any one of claims 1 to 5, characterized in that the antibody or a fragment thereof is linked to the immune activator by means of a ligand.

7. PHARMACEUTICAL COMPOSITION, for the treatment and / or prevention of cancer, characterized by comprising the conjugate, as defined in any one of claims 1 to 6, as the active ingredient. Petition 870260047669, dated 19 / 05 / 2026, p. 136 / 272 8 / 8 8. PHARMACEUTICAL COMPOSITION, according to claim 7, characterized in the cancer being a cancer that expresses a CAPRIN-1 protein on the cell membrane surface.

9. PHARMACEUTICAL COMPOSITION, according to any one of claims 7 to 8, characterized in the cancer being breast cancer, kidney cancer, pancreatic cancer, colorectal cancer, lung cancer, brain tumor, stomach cancer, uterine cancer, ovarian cancer, prostate cancer, bladder cancer, esophageal cancer, leukemia, lymphoma, liver cancer, gallbladder cancer, sarcoma, mast cell tumor, melanoma, adrenal cortex cancer, Ewing's tumor, Hodgkin's lymphoma, mesothelioma, multiple myeloma, testicular cancer, thyroid cancer or head and neck cancer.