Therapeutic or prophylactic agent targeting plasma cells in HTLV-1-associated myelopathy (HAM)

Abstract

To provide a therapeutic or prophylactic agent for HAM.SOLUTION: A therapeutic or prophylactic agent for HTLV-1-associated myelopathy (HAM), comprising a substance that inhibits an increase of plasma cells.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a therapeutic or prophylactic agent that targets plasma cells in HTLV-1-associated myelopathy (HAM). [Background technology]

[0002] Human T-cell leukemia virus type 1 (HTLV-1) is a virus that infects T cells (mainly CD4-positive T cells), a type of white blood cell in the blood. T cells infected with HTLV-1 cause chronic inflammation in the spinal cord, which results in damage and degeneration of spinal nerve cells, leading to spastic spinal paralysis and other conditions. Spastic spinal paralysis caused by HTLV-1-infected cells is called HTLV-1-associated myelopathy (hereinafter referred to as "HAM").

[0003] Symptoms of HAM include paralysis of both legs, pain, and urinary and defecation problems due to nerve tissue damage. As these symptoms progress, patients may become wheelchair-bound or bedridden. HAM is one of the diseases designated as an intractable disease in Japan, but currently, no effective treatment has been established for HAM, and symptomatic treatment is the only treatment available.

[0004] Known treatments for HAM include those using RGMa inhibitors such as anti-RGMa antibodies (see, for example, Patent Document 1).

[0005] Furthermore, Non-Patent Document 1 suggests that oligoclonal antibodies are detected in the cerebrospinal fluid of HAM patients and that humoral immunity is involved in the inflammatory pathology. On the other hand, stained images of lesions in HAM patients have confirmed that CD22-expressing cells, which are associated with humoral immunity, are distributed in small numbers (see, for example, Non-Patent Document 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2020 / 017629 [Non-patent literature]

[0007] [Non-Patent Document 1] Enose-Akahata Y et al. Immunophenotypic characterization of CSF B cells in virus-associated neuroinflammatory diseases. PLoS Pathog. 2018 Apr 30;14(4):e1007042. [Non-patent document 2] Umehara F et al. Journal of Neuropathology and Experimental Neurology. Vol 52, No.4, July, 1993 pp.424-430 Summary of the Invention [Problem to be solved by the invention]

[0008] As shown in Non-Patent Documents 1 and 2, it has been suggested that humoral immunity is involved in the inflammatory pathology of HAM patients. However, it has also been reported that CD22-expressing cells such as B cells are distributed in small numbers, and the underlying mechanism that causes inflammation in the lesions of HAM patients remains unclear.

[0009] Furthermore, autopsy of the spinal cord of HAM patients is extremely rare, and because the spinal cord is a complex tissue structure, it is extremely difficult to analyze the lesions in HAM patients at the single-cell level.

[0010] The problem to be solved by the present invention is to provide an agent for treating or preventing HAM. [Means for solving the problem]

[0011] In order to clarify the underlying mechanism of inflammatory pathology specific to HAM patients, the present inventors focused on spatial transcriptome analysis (Visium), which allows comprehensive analysis of gene expression while preserving spatial information, and performed this analysis. As a result, they found that large numbers of plasma cells infiltrate into HAM lesions. They also found that HAM can be treated or prevented by using a substance that suppresses the increase of plasma cells, leading to the completion of the present invention.

[0012] That is, the present invention includes the following embodiments. [1] A therapeutic or preventive agent for HTLV-1 associated myelopathy (HAM), which comprises a substance that suppresses the proliferation of plasma cells. [1'] In [1], the substance preferably suppresses the increase of plasma cells in the lesion. [2] The substance is (A) an antibody or antibody fragment thereof that binds to a protein expressed on the surface of at least one of B cells and plasma cells; (B) cells genetically modified to express a chimeric antigen receptor that binds to a protein expressed on the surface of at least one of B cells and plasma cells; and (C) Differentiation inhibitors that inhibit B cell differentiation into plasma cells At least one of [1] The therapeutic or preventive agent according to [1]. [3] the substance comprises the antibody (A) or its antibody fragment, and the antibody (A) or its antibody fragment has ADCC activity, CDC activity, or ADCP activity; [2] The therapeutic or preventive agent according to [2]. [4] the expressed protein is at least one of CD19, CD20, CD27, CD38, and CD138; [2] The therapeutic or preventive agent according to [2]. [5] the expressed protein is at least one of CD19, CD27, CD38, and CD138; [2] The therapeutic or preventive agent according to [2]. [6] the expressed protein is at least one of CD27, CD38, and CD138; [2] The therapeutic or preventive agent according to [2]. [7] the expressed protein is at least one of CD19, CD20, and CD38; [2] The therapeutic or preventive agent according to [2]. [8] (C) The differentiation inhibitor is a Bruton's tyrosine kinase (BTK) inhibitor. [2] The therapeutic or preventive agent according to [2]. [9] The substance suppresses the increase of plasma cells in the white matter region of the spinal cord. The therapeutic or prophylactic agent according to any one of [1] to [8].

[0013] The present invention also includes the following aspects. [A1] A method for treating or preventing HTLV-1 associated myelopathy (HAM), comprising administering to a patient in need thereof a therapeutically effective amount of a substance that suppresses the proliferation of plasma cells.

[0014] [B1] A substance that suppresses the proliferation of plasma cells for the treatment or prevention of HTLV-1-associated myelopathy (HAM).

[0015] [C1] Use of a substance that suppresses the proliferation of plasma cells to treat or prevent HTLV-1-associated myelopathy (HAM).

[0016] [D1] Use of a substance that suppresses the proliferation of plasma cells in the manufacture of an agent for treating or preventing HTLV-1-associated myelopathy (HAM).

[0017] [E1] A therapeutic or prophylactic agent for use in treating HTLV-1 associated myelopathy (HAM), comprising a substance that suppresses the proliferation of plasma cells.

[0018] [X1'] In [A1] to [E1], the substance preferably suppresses the increase of plasma cells in the lesion. [X2] In [A1]~[E1], The substance is (A) an antibody or antibody fragment thereof that binds to a protein expressed on the surface of at least one of B cells and plasma cells; (B) cells genetically modified to express a chimeric antigen receptor that binds to a protein expressed on the surface of at least one of B cells and plasma cells; and (C) Differentiation inhibitors that inhibit B cell differentiation into plasma cells It may be at least one of the following.

[0019] [X3] In [X2], The substance may comprise the antibody (A) or an antibody fragment thereof, and the antibody (A) or an antibody fragment thereof may have ADCC activity, CDC activity, or ADCP activity.

[0020] [X4] In [X2], The expressed protein may be at least one of CD19, CD20, CD27, CD38, and CD138.

[0021] [X5] In [X2], The expressed protein may be at least one of CD19, CD27, CD38, and CD138.

[0022] [X6] In [X2], The expressed protein may be at least one of CD27, CD38, and CD138. [X7] In [X2], The expressed protein is at least one of CD19, CD20, and CD38. That's fine.

[0023] [X8] In [X2], The differentiation inhibitor (C) may be a Bruton's tyrosine kinase (BTK) inhibitor.

[0024] [X9] In [A1]~[E1], [X2]~[X8], The substance may inhibit the proliferation of plasma cells in the white matter regions of the spinal cord.

[0025] In any of the inventions described in [1] to [9], [A1] to [E1], and [X2] to [X8], the configuration of the invention, such as a substance that suppresses the proliferation of plasma cells, may be any of the preferred embodiments described below as the present embodiments. Furthermore, in any of the inventions described in [1] to [9], [A1] to [E1], and [X2] to [X8], the configuration of the invention may be selected from any combination of the preferred embodiments described below as the present embodiments. Preferred embodiments include more preferred embodiments, even more preferred embodiments, and even more preferred embodiments. [Effects of the Invention]

[0026] According to the present invention, a therapeutic or preventive agent for HAM can be provided. [Brief explanation of the drawings]

[0027] [Figure 1] This figure shows the localization information of gene expression superimposed on an HE-stained image of the thoracic spinal cord. [Figure 2] This is a plot showing the gene expression level at each spot on a thin section. [Figure 3] FIG. 1 shows the inhibitory effect of removing CD20-expressing cells from PBMCs of HAM patients on cell proliferation in PBMCs of HAM patients. [Figure 4]FIG. 1 shows the inhibitory effect of removing CD19-expressing cells from PBMCs of HAM patients on cell proliferation in PBMCs of HAM patients. [Figure 5] FIG. 1 shows the inhibitory effect of adding an anti-CD19 antibody (inebilizumab) to PBMCs of HAM patients on cell proliferation of PBMCs of HAM patients. [Figure 6] FIG. 1 shows the inhibitory effect of adding an anti-CD20 antibody (Ofatumumab) to PBMCs of HAM patients on cell proliferation in the PBMCs of HAM patients. [Figure 7] FIG. 1 shows the inhibitory effect of adding an anti-CD38 antibody (Daratumumab) to PBMCs of HAM patients on cell proliferation of PBMCs of HAM patients. [Figure 8] FIG. 1 shows the cell proliferation inhibitory effect of adding a BTK inhibitor to PBMCs of HAM patients. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following examples.

[0029] The present disclosure includes the treatment or prevention of HTLV-1-associated myelopathy (HAM) by suppressing the proliferation of plasma cells. As shown in the Examples below, the present inventors have discovered that plasma cells are specifically increased in the lesions of HAM patients, and further that suppressing this proliferation of plasma cells leads to the treatment or prevention of HAM. Substances that suppress the proliferation of plasma cells are described below.

[0030] (Substance that suppresses the proliferation of plasma cells) Plasma cells are immune cells differentiated from B cells. As used herein, the term "B cells" refers to any cell that has differentiated from a hematopoietic stem cell to a plasma cell, including pre-B cells, B cells, immature B cells, mature B cells, activated B cells, and memory cells. The term "plasma cells" refers to any cell that has differentiated from a B cell, including short-lived plasma cells, early plasmablasts, late plasmablasts, and plasma cells.

[0031] Therefore, the B cells removed in this embodiment may be at least one type selected from the group consisting of pre-B cells, B cells, immature B cells, mature B cells, activated B cells, and memory cells. Furthermore, the plasma cells removed in this embodiment may be at least one type selected from the group consisting of short-lived plasma cells, early plasmablasts, late plasmablasts, and plasma cells.

[0032] Since plasma cells increase by differentiating from B cells, in this specification, "suppressing the increase of plasma cells" or "suppressing the increase of plasma cells in a lesion" may mean (1) suppressing the increase of plasma cells by removing B cells, (2) suppressing the increase of plasma cells by removing plasma cells, or (3) suppressing the increase of plasma cells by suppressing the differentiation of B cells into plasma cells. In principle, plasma cells have a short lifespan in the body, so suppressing the increase of plasma cells in this way is thought to lead to the treatment or prevention of HAM.

[0033] In this specification, the term "lesioned area" refers not only to the lesioned area in HAM patients but also to the area corresponding to the lesioned area in potential HAM patients having HTLV-1-infected cells (i.e., the area that potentially becomes a lesioned area). The lesioned area may be, for example, the spinal cord, the thoracic spinal cord, the white matter region of the thoracic spinal cord, or the anterior and lateral funiculus.

[0034] In this embodiment, it is presumed that suppressing the increase in plasma cells that are specifically increased in the lesions of HAM patients can suppress the amplification of inflammatory pathology specific to HAM patients, thereby leading to the treatment or prevention of HAM. However, the present invention is not limited to such presumption.

[0035] As used herein, "suppressing the increase in plasma cells" means that the increase in plasma cells in lesions is suppressed compared to when the therapeutic or prophylactic agent of this embodiment is not administered or when the therapeutic or prophylactic method of this embodiment is not performed. "Suppressing the increase in plasma cells" may also mean that the number of plasma cells in lesions is reduced or eliminated compared to before the therapeutic or prophylactic agent of this embodiment is administered or before the therapeutic or prophylactic method of this embodiment is performed. B cells and / or plasma cells may be removed by physically removing B cells or plasma cells, or by damaging or killing CCR8-expressing cells. B cells and / or plasma cells may be removed by physiological functions such as cytotoxic activity, or by cell-specific chemotherapy using antibody-drug conjugates (ADCs).

[0036] Specific examples of substances that suppress the proliferation of plasma cells include (A) an antibody or antibody fragment thereof that binds to a protein expressed on the surface of at least one of B cells and plasma cells, (B) cells genetically modified to express a chimeric antigen receptor that binds to a protein expressed on the surface of at least one of B cells and plasma cells, and (C) a differentiation inhibitor that suppresses the differentiation of B cells into plasma cells. Note that the (A) antibody or antibody fragment thereof and the (B) cells (1) suppress the proliferation of plasma cells by removing B cells, or (2) suppress the proliferation of plasma cells by removing plasma cells, and the (C) differentiation inhibitor suppresses the proliferation of plasma cells by (3) suppressing the differentiation of B cells into plasma cells.

[0037] ((A) An antibody or antibody fragment thereof that binds to a protein expressed on the surface of at least one of B cells and plasma cells) The substance that suppresses the proliferation of plasma cells may be an antibody or an antibody fragment thereof that binds to a protein expressed on the surface of at least one of B cells and plasma cells. In the following description, the description of each antibody also applies to the antibody fragment of that antibody. Therefore, in this specification, even if no reference is made to the antibody fragment of that antibody, the description of that antibody is understood to mean the description of the antibody fragment of that antibody.

[0038] Proteins expressed on the surface of B cells include, but are not limited to, CD19 and CD20. Proteins expressed on the surface of plasma cells include, but are not limited to, BAFF-R (B-cell activating factor receptor), CD27, CD38, and CD138. Therefore, proteins expressed on the surface of at least one of B cells and plasma cells include, but are not limited to, BAFF-R, CD19, CD20, CD27, CD38, and CD138. These antibodies are also referred to as anti-BAFF-R antibodies, anti-CD19 antibodies, anti-CD20 antibodies, anti-CD27 antibodies, anti-CD38 antibodies, and anti-CD138 antibodies, respectively.

[0039] In this embodiment, the (A) antibody or antibody fragment thereof preferably binds to at least one of CD19, CD20, CD27, CD38, and CD138, more preferably binds to at least one of CD19, CD27, CD38, and CD138, and even more preferably binds to at least one of CD27, CD38, and CD138. In this embodiment, the (A) antibody or antibody fragment thereof may bind to CD19 and CD20. It is also preferred that the (A) antibody or antibody fragment thereof binds to at least one of CD19, CD20, and CD38.

[0040] As used herein, the term "antibody" refers to a molecule having a structure in which two heavy chains (H chains) and two light chains (L chains) are associated and stabilized by a pair of disulfide bonds. Each of the two heavy chains consists of a heavy chain variable region VH, heavy chain constant regions CH1, CH2, and CH3, and a hinge region located between CH1 and CH2. The light chain consists of a light chain variable region VL and a light chain constant region CL. In an antibody, the variable region fragment (Fv) consisting of VH and VL is the region directly involved in binding to an antigen. The antigen-binding region consisting of VL, CL, VH, and CH1 is called the Fab region, and the region consisting of the hinge region, CH2, and CH3 is called the Fc region.

[0041] Within the variable region, the region that directly contacts the antigen undergoes particularly large changes and is called the complementarity-determining region (CDR). The region other than the CDR, which shows relatively little variation, is called the framework region (FR). The light chain and heavy chain variable regions each contain three CDRs (heavy chain CDRs 1-3 and light chain CDRs 1-3).

[0042] (A) To prepare antibodies that bind to proteins expressed on the surface of at least one of B cells and plasma cells (e.g., anti-BAFF-R antibodies, anti-CD19 antibodies, anti-CD20 antibodies, anti-CD27 antibodies, anti-CD38 antibodies, and anti-CD138 antibodies), the following may be used as antigens: cells in which the respective proteins (e.g., BAFF-R, CD19, CD20, CD27, CD38, and CD138) are forcibly expressed using an expression vector or the like; plasmid vectors for expressing the respective proteins (e.g., BAFF-R, CD19, CD20, CD27, CD38, and CD138); and viral vectors (adenovirus vectors) for expressing the respective proteins (e.g., BAFF-R, CD19, CD20, CD27, CD38, and CD138). The surface proteins (e.g., BAFF-R, CD19, CD20, CD27, CD38, and CD138) to which the (A) antibody or antibody fragment thereof binds are preferably derived from mammals. Mammals include, but are not limited to, humans, non-human primates, domestic animals, laboratory animals, and livestock, with humans being preferred. The full-length amino acid sequences of human BAFF-R, human CD19, human CD20, human CD27, human CD38, and human CD138 are shown in SEQ ID NOs: 1 to 6, respectively.

[0043] [Table 1]

[0044] The (A) antibody of this embodiment (e.g., anti-BAFF-R antibody, anti-CD19 antibody, anti-CD20 antibody, anti-CD27 antibody, anti-CD38 antibody, and anti-CD138 antibody) is not particularly limited, and examples include monoclonal antibodies and polyclonal antibodies.

[0045] As used herein, the term "monoclonal antibody" refers to an antibody obtained from a population of substantially homogeneous antibodies, produced, for example, by hybridoma techniques, recombinant DNA techniques, phage display techniques, or techniques utilizing transgenic animals containing all or part of the human immunoglobulin loci, or a combination thereof, without limitation.

[0046] As used herein, the term "polyclonal antibody" refers to a mixture of different antibodies that recognize multiple epitopes on a single antigen. Polyclonal antibodies are produced, but are not limited to, by administering an immunogen containing the antigen of interest to mammals (e.g., rats, mice, rabbits, cows, monkeys, etc.) or birds (e.g., chickens, etc.).

[0047] The (A) antibodies of this embodiment (e.g., anti-BAFF-R antibodies, anti-CD19 antibodies, anti-CD20 antibodies, anti-CD27 antibodies, anti-CD38 antibodies, and anti-CD138 antibodies) may be antibody-drug conjugates (ADCs) that are conjugated with other drugs. Furthermore, the antibodies conjugated to drugs are not particularly limited as long as they can bind to the respective proteins (e.g., BAFF-R, CD19, CD20, CD27, CD38, and CD138), and may be antibodies (e.g., anti-BAFF-R antibodies, anti-CD19 antibodies, anti-CD20 antibodies, anti-CD27 antibodies, anti-CD38 antibodies, and anti-CD138 antibodies) or antigen-binding fragments of such antibodies. The drug for constructing an ADC is not particularly limited, and various drugs such as anticancer drugs, nucleic acid drugs, and immunomodulatory drugs (IMiDs) can be used.

[0048] As used herein, the term "antibody fragment" refers to a molecule comprising a portion of an antibody and capable of binding to the same antigen as the antibody. Examples of antibody fragments include, but are not limited to, Fab, F(ab'), Fv, Fab', single-chain antibody molecules (e.g., scFv), disulfide-stabilized antibodies (dsFv), dimeric V-region fragments (diabodies), and CDR-containing peptides. The antibody fragment may be a VHH antibody (variable domain of heavy chain of heavy chain antibody) as long as it can bind to the respective proteins (e.g., BAFF-R, CD19, CD20, CD27, CD38, and CD138).

[0049] The (A) antibodies of this embodiment (e.g., anti-BAFF-R antibodies, anti-CD19 antibodies, anti-CD20 antibodies, anti-CD27 antibodies, anti-CD38 antibodies, and anti-CD138 antibodies) may have a structure known as an antibody and may be any of the isotypes IgG, IgM, IgA, IgD, and IgE. IgG is an immunoglobulin with a γ heavy chain and is produced as part of a secondary immune response to an antigen. IgM is an immunoglobulin with a μ heavy chain and exists as a pentamer in mammals. IgA is an immunoglobulin with an α heavy chain, IgD is an immunoglobulin with an ε heavy chain, and IgE is an immunoglobulin with a δ heavy chain.

[0050] The (A) antibody of this embodiment (e.g., anti-BAFF-R antibody, anti-CD19 antibody, anti-CD20 antibody, anti-CD27 antibody, anti-CD38 antibody, and anti-CD138 antibody) may be a chimeric antibody, a humanized antibody, a human antibody, or the like, and is preferably a humanized antibody or a human antibody. The binding fragment of the (A) antibody of this embodiment may be an antigen-binding fragment of a chimeric antibody, an antigen-binding fragment of a humanized antibody, a binding fragment of a human antibody, or the like. A chimeric antibody is an antibody in which fragments of antibodies derived from different species are linked. A humanized antibody is an antibody in which a non-human CDR amino acid sequence is grafted onto a human antibody. The humanized antibody is not particularly limited, and examples include antibodies having heavy chain CDRs 1 to 3 and light chain CDRs 1 to 3 of an antibody produced by immunizing a mouse or rat, with all other regions derived from a human antibody. The term "humanized antibody" may also refer to a human chimeric antibody.

[0051] In the (A) antibodies of this embodiment (e.g., anti-BAFF-R antibodies, anti-CD19 antibodies, anti-CD20 antibodies, anti-CD27 antibodies, anti-CD38 antibodies, and anti-CD138 antibodies), regions other than the CDRs when the CDRs are defined, and regions other than the variable regions when the heavy chain variable region and / or light chain variable region are defined, may be selected from regions of conventional antibodies, as long as the (A) antibodies of this embodiment (e.g., anti-BAFF-R antibodies, anti-CD19 antibodies, anti-CD20 antibodies, anti-CD27 antibodies, anti-CD38 antibodies, and anti-CD138 antibodies) have the ability to bind to proteins expressed on the surface of at least one of B cells and plasma cells (e.g., BAFF-R, CD19, CD20, CD27, CD38, and CD138).

[0052] In this embodiment, the anti-CD19 antibody is not particularly limited as long as it is derived from an antibody that binds to CD19, and may be a known or commercially available anti-CD19 antibody. For example, the following antibodies are known as anti-CD19 antibodies: 1) Anti-CD19 antibodies described in WO 2008 / 031056 2) Anti-CD19 monoclonal antibody manufactured by Novus Biologicals (Product name: CD19 antibody, Cat. No.: NBP2-25196) 3) Anti-CD19 monoclonal antibody manufactured by Abcam (product name: Anti-CD19 antibody, product codes: ab245235, ab134114, ab28836) 4) Anti-CD19 polyclonal antibody manufactured by Abcam (product name: Anti-CD19 antibody, product codes: ab86902, ab203615, ab245321) 5) Anti-CD19 monoclonal antibody manufactured by Sigma-Aldrich (product name: Monoclonal Anti-CD19 antibody produced in mouse, product code: SAB1403645) Furthermore, the anti-CD19 antibody may comprise an amino acid sequence that is 80% or more, 85% or more, 90% or more, or 95% or more identical to the amino acid sequence of a known anti-CD19 antibody. Furthermore, when amino acids have been deleted, substituted, or added in the amino acid sequence of such a known antibody, the deletion, substitution, or addition of amino acids is preferably in a region other than the CDRs or a region other than the variable region.

[0053] The anti-CD19 antibody may be an isolated and purified humanized monoclonal antibody or antibody fragment thereof comprising a VH domain comprising the amino acid sequence of SEQ ID NO: 7 and a VL domain comprising the amino acid sequence of SEQ ID NO: 8, and which binds to the human CD19 antigen.

[0054] [Table 2]

[0055] In this embodiment, the anti-CD20 antibody is not particularly limited as long as it is derived from an antibody that binds to CD20, and may be a known or commercially available anti-CD20 antibody. For example, the following antibodies are known as anti-CD20 antibodies: 1) CD20 antibodies described in WO 1993 / 002108 2) CD20 antibodies described in WO 2004 / 035607 3) Anti-CD20 monoclonal antibody manufactured by Novus Biologicals (Product name: CD20 antibody, Cat. No.: NBP1-43435) 4) Anti-CD20 monoclonal antibody manufactured by Abcam (product name: Anti-CD20 antibody, product codes: ab78237, ab64088, ab219329) 5) Anti-CD20 polyclonal antibody manufactured by Abcam (product name: Anti-CD20 antibody, product codes: ab244386, ab194970, ab27093) 6) Anti-CD20 monoclonal antibody manufactured by Sigma-Aldrich (product name: Monoclonal Anti-CD20 antibody produced in mouse, product code: SAB4700114) Furthermore, the anti-CD20 antibody may comprise an amino acid sequence that is 80% or more, 85% or more, 90% or more, or 95% or more identical to the amino acid sequence of a known anti-CD20 antibody. Furthermore, when amino acids have been deleted, substituted, or added in the amino acid sequence of such a known antibody, the deletion, substitution, or addition of amino acids is preferably in a region other than the CDRs or a region other than the variable region. The anti-CD20 antibody may be an isolated human monoclonal antibody that binds to human CD20, and may be an antibody or antigen-binding fragment thereof, comprising a human heavy chain variable region and a human kappa light chain variable region comprising the amino acid sequences set forth in SEQ ID NO: 15 and SEQ ID NO: 16, respectively, where the definitions of each term are as set forth in WO 2004 / 035607. [Table 3]

[0056] In this embodiment, the anti-CD27 antibody is not particularly limited as long as it is derived from an antibody that binds to CD27, and may be a known or commercially available anti-CD27 antibody. For example, the following antibodies are known as anti-CD27 antibodies: 1) CD27 antibodies described in WO 2010 / 001908 2) CD27 antibodies described in WO 2018 / 058022 3) Anti-CD27 monoclonal antibody manufactured by Novus Biologicals (Product name: CD27 / TNFRSF7 Antibody, Cat. No.: AF382) 4) Anti-CD27 monoclonal antibody manufactured by Abcam (product name: Anti-CD27 antibody, product codes: ab131254, ab133761, ab265589) 5) Anti-CD27 polyclonal antibody manufactured by Abcam (product name: Anti-CD27 antibody, product codes: ab175403, ab226256, ab181406) 6) Anti-CD27 polyclonal antibody manufactured by Sigma-Aldrich (product name: Anti-CD27 antibody produced in rabbit, product code: SAB5700991) Furthermore, the anti-CD27 antibody may comprise an amino acid sequence that is 80% or more, 85% or more, 90% or more, or 95% or more identical to the amino acid sequence of a known anti-CD27 antibody. Furthermore, when the amino acid sequence of such a known antibody has amino acid deletions, substitutions, or additions, the amino acid deletions, substitutions, or additions are preferably in a region other than the CDRs or a region other than the variable region.

[0057] In this embodiment, the anti-CD38 antibody is not particularly limited as long as it is derived from an antibody that binds to CD38, and may be a known or commercially available anti-CD38 antibody. For example, the following antibodies are known as anti-CD38 antibodies: 1) CD38 antibodies described in WO 2006 / 099875 2) Anti-CD38 monoclonal antibody manufactured by Novus Biologicals (Product name: CD38 Antibody, Cat. No.: NBP1-47462) 3) Anti-CD38 monoclonal antibody manufactured by Abcam (product name: Anti-CD38 antibody, product codes: ab108403, ab235118, ab183326) 4) Anti-CD38 polyclonal antibody manufactured by Abcam (product name: Anti-CD38 antibody, product code: ab244390) 5) Anti-CD38 polyclonal antibody manufactured by Sigma-Aldrich (product name: Anti-CD38 antibody produced in rabbit, product code: HPA052381) Furthermore, the anti-CD38 antibody may comprise an amino acid sequence that is 80% or more, 85% or more, 90% or more, or 95% or more identical to the amino acid sequence of a known anti-CD38 antibody. Furthermore, when amino acids have been deleted, substituted, or added in the amino acid sequence of such a known antibody, the deletion, substitution, or addition of amino acids is preferably in a region other than the CDRs or a region other than the variable region.

[0058] The anti-CD38 antibody may be an antibody or antibody fragment thereof that binds to human CD38, comprising a human light chain variable region and a human heavy chain variable region, wherein the light chain variable region comprises a VL CDR1 having the amino acid sequence of SEQ ID NO: 9, a VL CDR2 having the amino acid sequence of SEQ ID NO: 10, and a VL CDR3 having the amino acid sequence of SEQ ID NO: 11, and the heavy chain variable region comprises a VH CDR1 having the amino acid sequence of SEQ ID NO: 12, a VH CDR2 having the amino acid sequence of SEQ ID NO: 13, and a VH CDR3 having the amino acid sequence of SEQ ID NO: 14.

[0059] [Table 4]

[0060] In this embodiment, the anti-CD138 antibody is not particularly limited as long as it is derived from an antibody that binds to CD138, and may be a known or commercially available anti-CD138 antibody. For example, the following antibodies are known as anti-CD138 antibodies: 1) CD138 antibody described in WO 2009 / 080829 2) Anti-CD138 monoclonal antibody manufactured by Novus Biologicals (Product Name: Syndecan-1 / CD138 Antibody, Cat. No.: NB100-64980) 3) Anti-CD138 monoclonal antibody manufactured by Abcam (product name: Anti-Syndecan-1 antibody, product codes: ab128936, ab130405, ab181789) 4) Anti-CD138 polyclonal antibody manufactured by Abcam (product name: Anti-Syndecan-1 antibody, product code: ab60199, ab16037) 5) Anti-CD138 monoclonal antibody manufactured by Sigma-Aldrich (product name: MONOCLONAL ANTI-CD138 (C-TERMINAL) antibody produced in mouse, product code: SAB1305542) Furthermore, the anti-CD138 antibody may comprise an amino acid sequence that is 80% or more, 85% or more, 90% or more, or 95% or more identical to the amino acid sequence of a known anti-CD138 antibody. Furthermore, when amino acids have been deleted, substituted, or added in the amino acid sequence of such a known antibody, the deletion, substitution, or addition of amino acids is preferably in a region other than the CDRs or a region other than the variable region.

[0061] In this embodiment, the anti-BAFF-R antibody is not particularly limited as long as it is derived from an antibody that binds to BAFF-R, and may be a publicly known or commercially available anti-BAFF-R antibody. For example, the following antibodies are known as anti-BAFF-R antibodies: 1) Anti-BAFF-R antibodies described in WO 2017 / 214170 2) Anti-BAFF-R polyclonal antibody manufactured by Abcam (product name: Anti-BAFF-R antibody, product code: ab5965) 3) Anti-BAFF-R monoclonal antibody manufactured by Abcam (product name: Anti-BAFF-R antibody [EPR10914], product code: ab168389) Furthermore, the anti-BAFF-R antibody may comprise an amino acid sequence that is 80% or more, 85% or more, 90% or more, or 95% or more identical to the amino acid sequence of a known anti-BAFF-R antibody. Furthermore, when amino acids have been deleted, substituted, or added in the amino acid sequence of such a known antibody, the deletion, substitution, or addition of amino acids is preferably in a region other than the CDR or a region other than the variable region.

[0062] In this embodiment, the antibody or antibody fragment thereof is a protein having an amino acid sequence of any one of SEQ ID NOs: 1 to 6; a protein comprising an amino acid sequence corresponding to an extracellular region, which is a partial sequence of any of the amino acid sequences of SEQ ID NOs: 1 to 6; A protein comprising an amino acid sequence in which one or more amino acids have been deleted, substituted, or added in any of the amino acid sequences of SEQ ID NO: 1, and which retains the function of each surface protein (e.g., BAFF-R, CD19, CD20, CD27, CD38, and CD138), or A protein comprising an amino acid sequence having 80% or more, 85% or more, 90% or more, or 95% or more identity with any of the amino acid sequences of SEQ ID NO: 1, and retaining the function of each surface protein (e.g., BAFF-R, CD19, CD20, CD27, CD38, and CD138). Preferably, the antibody or antibody fragment thereof binds to Herein, in the case where one or more amino acids have been deleted, substituted, or added in an amino acid sequence, the term "more than one" may mean, for example, 2 to 15, 2 to 10, 3 to 9, 4 to 8, 5 to 7, 2 to 8, 2 to 6, 2 to 5, or 2 to 4.

[0063] In this embodiment, the (A) antibody (e.g., anti-BAFF-R antibody, anti-CD19 antibody, anti-CD20 antibody, anti-CD27 antibody, anti-CD38 antibody, and anti-CD138 antibody) may have a neutralizing effect on each surface protein, and from the viewpoint of removing B cells and / or plasma cells, it preferably has antibody-dependent cellular cytotoxicity (ADCC activity), complement-dependent cytotoxicity (CDC activity), or antibody-dependent cellular phagocytosis (ADCP activity), and more preferably has ADCC activity.

[0064] The method for producing the (A) antibodies of this embodiment (e.g., anti-BAFF-R antibodies, anti-CD19 antibodies, anti-CD20 antibodies, anti-CD27 antibodies, anti-CD38 antibodies, and anti-CD138 antibodies) is not particularly limited. For example, in the case of monoclonal antibodies, it may be a method in which antibody-producing cells are isolated from a non-human mammal immunized with the respective surface proteins (e.g., BAFF-R, CD19, CD20, CD27, CD38, or CD138), and these are fused with myeloma cells or the like to produce hybridomas, and the antibodies produced by these hybridomas are purified. Furthermore, polyclonal antibodies may be obtained from the serum of animals immunized with the respective surface proteins (e.g., BAFF-R, CD19, CD20, CD27, CD38, or CD138).

[0065] When the (A) antibody of this embodiment (e.g., anti-BAFF-R antibody, anti-CD19 antibody, anti-CD20 antibody, anti-CD27 antibody, anti-CD38 antibody, and anti-CD138 antibody) is produced by genetic recombination, for example, suitable host cells may be transformed with an expression vector containing a nucleic acid encoding the (A) antibody of this embodiment (e.g., anti-BAFF-R antibody, anti-CD19 antibody, anti-CD20 antibody, anti-CD27 antibody, anti-CD38 antibody, or anti-CD138 antibody), and the resulting transformant may be cultured under appropriate conditions to express the antibody. The antibody may then be isolated and purified by known methods or methods equivalent thereto.

[0066] Methods for isolating and purifying antibodies are not particularly limited, and examples include column purification using an affinity column using protein A or other chromatography columns, filter filtration, ultrafiltration, salting out, dialysis, and the like, and these may be combined as appropriate.

[0067] When the (A) antibody of this embodiment (for example, an anti-BAFF-R antibody, an anti-CD19 antibody, an anti-CD20 antibody, an anti-CD27 antibody, an anti-CD38 antibody, or an anti-CD138 antibody) has CDRs consisting of amino acid sequences in which amino acids have been added, substituted, or deleted from the amino acid sequences of the heavy chain CDRs 1 to 3 and the light chain CDRs 1 to 3, or when the heavy chain CDRs 1 to 3 and the light chain CDRs 1 to 3 have CDRs consisting of amino acid sequences that share 80% or more identity, the antibody may be produced using known methods such as site-directed mutagenesis, random mutagenesis, chain shuffling, and CDR walking.

[0068] It is well known to those skilled in the art that antibodies or antigen-binding fragments thereof having a set of CDRs with greater affinity maturity can be obtained by displaying antibodies or antigen-binding fragments thereof with various mutations in the CDRs on the surface of phages using phage display methods and screening them using antigens (e.g., Nature Biotechnology 23, 1105 (2005)). Therefore, antibodies (A) of this embodiment (e.g., anti-BAFF-R antibodies, anti-CD19 antibodies, anti-CD20 antibodies, anti-CD27 antibodies, anti-CD38 antibodies, and anti-CD138 antibodies) may be produced by this method.

[0069] Chimeric antibodies, humanized antibodies, and human antibodies may be prepared by known methods or methods similar thereto. The antibody gene may be cloned from the mRNA of a hybridoma that produces an antibody from a non-human animal, and then linked to a part of a human antibody gene by genetic recombination techniques, to prepare the antibody.

[0070] There are no particular limitations on the method for producing chimeric antibodies. For example, chimeric antibodies may be produced using nucleic acids obtained by replacing the heavy chain variable region (VH) and light chain variable region (LH) with sequences derived from a human antibody by genetic recombination. Alternatively, the heavy and light chain constant regions of human IgG1 may be cloned, and for each of the heavy and light chains, for example, the heavy chain variable region (VH) and light chain variable region (LH) may be linked to a human antibody-derived constant region by PCR using the overlapping hanging method. The amplified DNA may then be inserted into an appropriate vector, which may then be transformed to obtain a chimeric antibody.

[0071] To produce a humanized antibody, the variable region of a human antibody is cloned and then modified by site-directed mutagenesis using the megaprimer method to alter the CDR nucleotide sequence of the antibody (e.g., anti-BAFF-R antibody, anti-CD19 antibody, anti-CD20 antibody, anti-CD27 antibody, anti-CD38 antibody, and anti-CD138 antibody). If humanization of the amino acid sequence constituting the framework region results in a loss of specific binding to the antigen, some amino acids in the framework may be converted from human to rat types.

[0072] CDRs consisting of an amino acid sequence in which one or more amino acids have been deleted, substituted, or added in the amino acid sequence of the original CDR, or CDRs consisting of an amino acid sequence that is 80% or more identical to the original sequence, may be prepared using known methods such as site-directed mutagenesis, random mutagenesis, chain shuffling, and CDR walking.

[0073] Whether the antibodies obtained by the above production methods (e.g., anti-BAFF-R antibodies, anti-CD19 antibodies, anti-CD20 antibodies, anti-CD27 antibodies, anti-CD38 antibodies, and anti-CD138 antibodies) are the desired antibodies can be confirmed, for example, by the ability to detect each protein in a sample by immunological assay using each antibody. Immunoassays for detecting a target protein by immunological measurement are well known in the art. Reagents required for each immunoassay are also well known, and each protein may be immunologically detected using a conventional immunoassay kit using each antibody as the antibody used in the immunoassay. The immunoassay is not particularly limited, but examples thereof include immunohistochemistry (IHC), immunofluorescence (IF), flow cytometry, enzyme-linked immunosorbent assay (ELISA), immunoblotting, and the like.

[0074] (B) Cells genetically engineered to express a chimeric antigen receptor that binds to a protein expressed on the surface of at least one of B cells and plasma cells. The substance that suppresses the proliferation of plasma cells may be cells that have been genetically modified to express a chimeric antigen receptor that binds to a protein expressed on the surface of at least one of B cells and plasma cells. Herein, a chimeric antigen receptor (CAR) is also referred to as a CAR (chimeric antigen receptor). CAR is an artificial chimeric protein having, in order from the N-terminus of the CAR, an extracellular domain, a transmembrane domain, and an intracellular domain. Herein, each antibody, including an anti-BAFF-R antibody, an anti-CD19 antibody, an anti-CD20 antibody, an anti-CD27 antibody, an anti-CD38 antibody, and an anti-CD138 antibody, may be the same as those described above.

[0075] The extracellular domain preferably has, in order from the N-terminus of the CAR, an antigen-binding domain and a hinge region. The antigen-binding domain of the CAR of this embodiment that binds to a protein expressed on the surface of at least one of B cells and plasma cells (e.g., BAFF-R, CD19, CD20, CD27, CD38, or CD138) is not particularly limited as long as it can bind to a protein expressed on the surface of at least one of B cells and plasma cells. Examples of the antigen-binding domain include the above-mentioned antibody (A) (e.g., anti-BAFF-R antibody, anti-CD19 antibody, anti-CD20 antibody, anti-CD27 antibody, anti-CD38 antibody, or anti-CD138 antibody). Preferably, the antibody (A) has the antigen-binding region of the aforementioned antibody (A) (e.g., anti-BAFF-R antibody, anti-CD19 antibody, anti-CD20 antibody, anti-CD27 antibody, anti-CD38 antibody, or anti-CD138 antibody), more preferably has the heavy chain variable region and / or light chain variable region of the aforementioned antibody (A) (e.g., anti-BAFF-R antibody, anti-CD19 antibody, anti-CD20 antibody, anti-CD27 antibody, anti-CD38 antibody, or anti-CD138 antibody), and particularly preferably has the complementarity-determining region of the aforementioned antibody (A) (e.g., anti-BAFF-R antibody, anti-CD19 antibody, anti-CD20 antibody, anti-CD27 antibody, anti-CD38 antibody, or anti-CD138 antibody). Furthermore, the antigen-binding domain preferably has a single-chain antibody (scFv) structure comprising the heavy chain variable region and light chain variable region of the aforementioned antibody (A) (e.g., anti-BAFF-R antibody, anti-CD19 antibody, anti-CD20 antibody, anti-CD27 antibody, anti-CD38 antibody, or anti-CD138 antibody). In scFv, either the heavy chain variable region or the light chain variable region may be located on the N-terminal side of the CAR, and a linker peptide consisting of any oligopeptide or polypeptide may be provided between the heavy chain variable region and the light chain variable region. The linker peptide is not particularly limited, but examples include peptides consisting of 1 to 100 amino acid residues, and preferably peptides consisting of 10 to 50 amino acid residues.

[0076] CAR is a protein having an amino acid sequence of any one of SEQ ID NOs: 1 to 6; a protein comprising an amino acid sequence corresponding to an extracellular region, which is a partial sequence of any of the amino acid sequences of SEQ ID NOs: 1 to 6; A protein comprising an amino acid sequence in which one or more amino acids have been deleted, substituted, or added in any of the amino acid sequences of SEQ ID NO: 1, and which retains the function of each surface protein (e.g., BAFF-R, CD19, CD20, CD27, CD38, and CD138), or A protein comprising an amino acid sequence having 80% or more, 85% or more, 90% or more, or 95% or more identity with any of the amino acid sequences of SEQ ID NO: 1, and retaining the function of each surface protein (e.g., BAFF-R, CD19, CD20, CD27, CD38, and CD138). It is preferred to bind to

[0077] The hinge region is not particularly limited, but examples include peptides consisting of 1 to 100 amino acid residues, and preferably 10 to 70 amino acid residues. As the hinge region of the CAR, for example, the constant region of the antibody (A) of this embodiment (e.g., anti-BAFF-R antibody, anti-CD19 antibody, anti-CD20 antibody, anti-CD27 antibody, anti-CD38 antibody, or anti-CD138 antibody) may be used as the hinge, or an amino acid sequence derived from a molecule other than these antibodies (e.g., CD8, CD28, etc.) may be selected.

[0078] The transmembrane domain is a structure that anchors the CAR to the cell membrane. Examples of the transmembrane domain of the CAR include, but are not limited to, polypeptides derived from proteins such as CD8, the α and β chains of the T cell receptor, and CD28.

[0079] The intracellular domain preferably has a costimulatory domain and a signal transduction domain. The costimulatory domain is not particularly limited, but examples thereof include costimulatory factors contained in T cells, such as CD28 and 4-1BB. The signal transduction domain is not particularly limited, but examples thereof include structures derived from CD3ζ and the like.

[0080] A spacer region consisting of any oligopeptide or polypeptide may be provided between the transmembrane domain and the intracellular domain. The spacer region is not particularly limited, but may be, for example, a peptide consisting of 1 to 100 amino acid residues, preferably 10 to 50 amino acid residues.

[0081] Cells genetically modified to express a chimeric antigen receptor that binds to a protein expressed on the surface of at least one of B cells and plasma cells include cells genetically modified to express a polynucleotide encoding a chimeric antigen receptor that binds to the above-mentioned surface proteins (e.g., BAFF-R, CD19, CD20, CD27, CD38, or CD138).

[0082] From the perspective of removing B cells and / or plasma cells, cells genetically modified to express a chimeric antigen receptor that binds to a protein expressed on the surface of at least one of B cells and plasma cells (e.g., BAFF-R, CD19, CD20, CD27, CD38, or CD138) preferably have cytotoxic activity. Examples of such cells include T cells and natural killer cells, with T cells being preferred. T cells genetically modified to express a chimeric antigen receptor are also called CAR-T cells.

[0083] Preferably, the genetically modified cells express a polynucleotide encoding a chimeric antigen receptor that binds to a protein expressed on the surface of at least one of B cells and plasma cells (e.g., BAFF-R, CD19, CD20, CD27, CD38, or CD138), such that the extracellular domain of the chimeric antigen receptor is exposed to the outside of the cell, and the transmembrane domain and intracellular domain are localized in the cell membrane or intracellularly.

[0084] Methods for genetically modifying cells to express a chimeric antigen receptor can be, for example, methods known as methods for producing CAR-T cells.

[0085] One aspect of this embodiment is a chimeric antigen receptor that binds to a protein expressed on the surface of at least one of B cells and plasma cells. One aspect of this embodiment is a polynucleotide encoding a chimeric antigen receptor that binds to a protein expressed on the surface of at least one of B cells and plasma cells. One aspect of this embodiment is a cell that harbors a polynucleotide encoding a chimeric antigen receptor that binds to a protein expressed on the surface of at least one of B cells and plasma cells. In one aspect of this embodiment, cells that harbor a polynucleotide encoding a chimeric antigen receptor that binds to a protein expressed on the surface of at least one of B cells and plasma cells are chimeric antibody receptor T cells (CAR-T cells). Here, the surface protein to which the chimeric antigen receptor binds may be at least one selected from the group consisting of BAFF-R, CD19, CD20, CD27, CD38, and CD138, preferably at least one selected from the group consisting of CD19, CD20, CD27, CD38, and CD138, more preferably at least one selected from the group consisting of CD19, CD27, CD38, and CD138, even more preferably CD27, CD38, and CD138. It is also preferred that the surface protein to which the chimeric antigen receptor binds is at least one selected from the group consisting of CD19, CD20, and CD38.

[0086] ((C) Differentiation inhibitors that inhibit the differentiation of B cells into plasma cells) The substance that suppresses the proliferation of plasma cells may be a differentiation inhibitor that suppresses the differentiation of B cells into plasma cells. Examples of such differentiation inhibitors include, but are not limited to, Bruton's tyrosine kinase (BTK) inhibitors. BTK is a cytoplasmic non-receptor tyrosine kinase belonging to the Tec kinase family and contains five signaling domains (BURGER, Jan A. BTK inhibitors: present and future. Cancer Journal (Sudbury, Mass.), 2019, 25.6: 386). BTK is primarily expressed in hematopoietic cells, particularly B cells, myeloid cells, and platelets, but at lower levels in T lymphocytes and plasma cells. Activated BTK promotes downstream signaling cascades that lead to B cell survival, proliferation, and differentiation. The present inventors have found that microglia, as well as plasma cells, are predominantly localized at the lesion site of HAM. BTK inhibitors can effectively suppress the inflammatory pathology of HAM not only by inhibiting B cell differentiation into plasma cells but also by simultaneously suppressing microglial development.

[0087] In this embodiment, the BTK inhibitor is not particularly limited as long as it has the property of inhibiting BTK, and may be a known or commercially available BTK inhibitor. For example, the following inhibitors are known as BTK inhibitors: 1) BTK inhibitors described in WO 2011 / 152351, WO 2008 / 039218, WO 2008 / 121742, WO 2013 / 010868, WO 2012 / 170976, WO 2013 / 067274, WO 2011 / 162515, WO 2009 / 158571, WO 2013 / 185084, WO 2014 / 173289, WO 2014 / 039899, ​​WO 2014 / 210085, WO 2016 / 065226, etc. 2) BTK inhibitor manufactured by Abcam (product name: Ibrutinib (PCI-32765), BTK inhibitor, product code: ab254447) 3) BTK inhibitors manufactured by Sigma-Aldrich (product name: LFM-A13, product code: 435300, product name: (-)-Terreic Acid, Synthetic, product code: 581810) The BTK inhibitor may also be a pharmaceutically acceptable salt of a known BTK inhibitor, such as fenebrutinib or tolebrutinib.

[0088] In this embodiment, the "pharmaceutically acceptable salt" may be an acid addition salt or a base addition salt. Examples of acid addition salts include lower alkanesulfonates such as camsylate (camphorsulfonate), mesylate (methanesulfonate), trifluoromethanesulfonate, and ethanesulfonate; arylsulfonates such as tosylate (p-toluenesulfonate) and benzenesulfonate; inorganic acid salts such as phosphate, nitrate, perchlorate, and sulfate; hydrohalide salts such as hydrochloride, hydrobromide, hydroiodide, and hydrofluoride; organic acid salts such as acetate, malate, fumarate, succinate, citrate, tartrate, oxalate, and maleate; and amino acid salts such as ornithine, glutamate, and aspartate. Examples of base addition salts include alkali metal salts such as sodium salt, potassium salt, and lithium salt; alkaline earth metal salts such as calcium salt and magnesium salt; inorganic salts such as ammonium salt; organic amine salts such as dibenzylamine salt, morpholine salt, phenylglycine alkyl ester salt, ethylenediamine salt, N-methylglucamine salt, diethylamine salt, triethylamine salt, cyclohexylamine salt, dicyclohexylamine salt, N,N'-dibenzylethylenediamine salt, diethanolamine salt, N-benzyl-N-(2-phenylethoxy)amine salt, piperazine salt, tetramethylammonium salt, and tris(hydroxymethyl)aminomethane salt; and amino acid salts such as arginine salt.

[0089] (Therapeutic or preventive agent) The therapeutic or preventive agent for HAM of this embodiment contains a substance that suppresses the proliferation of plasma cells. Here, the substance that suppresses the proliferation of plasma cells may be the same as those described above.

[0090] As used herein, the term "treatment or prophylaxis" refers to therapeutic and / or prophylactic treatment. The term "therapeutic or prophylactic treatment" is art-recognized and may include administration of a therapeutic or prophylactic agent to a subject. Therapeutic treatment may refer to administration after the onset of an undesired condition (e.g., a disease or other undesired condition of interest) and may be intended to attenuate, suppress, reverse, alleviate, or stabilize an existing undesired condition or its side effects. It also includes prevention of attenuation of any direct or indirect pathological effects of the disease. It may also refer to treatment to delay the onset of the disease or slow the progression of the disease. Prophylactic treatment may refer to administration prior to clinical manifestation of an undesired condition and may be intended to inhibit and / or prevent the recurrence of the undesired condition.

[0091] As used herein, the term "therapeutic or prophylactic agent" refers to a pharmaceutical composition for treatment or prevention that contains an active ingredient and additives (such as pharmaceutically acceptable ingredients), and may refer to a pharmaceutical formulation or pharmaceutical preparation commonly used in the art. In this embodiment, the therapeutic or prophylactic agent contains at least a substance that suppresses the proliferation of plasma cells as an active ingredient.

[0092] In this embodiment, the effect of treating or preventing HAM may be achieved by depleting B cells and / or plasma cells. In this embodiment, depletion of B cells and / or plasma cells may mean physically removing B cells or plasma cells, damaging B cells and / or plasma cells, or killing B cells and / or plasma cells. The term "damaging B cells and / or plasma cells" is not particularly limited, but includes, for example, the damage to B cells and / or plasma cells through antibody-dependent cellular cytotoxicity (ADCC activity), complement-dependent cytotoxicity (CDC activity), and antibody-dependent cellular phagocytosis (ADCP activity). ADCC activity is the activity in which, when an antibody binds to a cell expressing a target antigen, the antibody recruits immune cells in the body, such as natural killer (NK) cells and macrophages, to the vicinity, and induces the immune cells to kill the cell to which the antibody is bound. CDC activity is an activity in which an antibody recruits complement to its vicinity and induces damage to the cells to which the antibody is bound by the action of the complement. ADCP activity is an activity in which an antibody recruits macrophages to its vicinity and induces the recruited macrophages to phagocytose cells present in the vicinity of the antibody. The presence or absence of ADCC activity, CDC activity, and ADCP activity, and the strength of these activities can be measured by known methods.

[0093] One aspect of this embodiment is a therapeutic agent for HAM. Treatment of HAM is not particularly limited, and may mean that the number of HTLV-1-infected cells in a subject is reduced, HTLV-1-infected cells are eliminated, or proliferation of HTLV-1-infected cells is suppressed, or various symptoms caused by HAM (e.g., inflammation) are improved, by single-agent administration or combination therapy of the therapeutic agent of this embodiment.

[0094] One aspect of this embodiment is a preventive agent for HAM. Prevention of HAM is not particularly limited, and may mean preventing the onset of HAM in asymptomatic HTLV-1-infected individuals or suppressing the recurrence of HAM by single-drug administration or combination therapy of the preventive agent of this embodiment, and preferably means preventing an increase in the number of HTLV-1-infected cells due to regrowth of reduced HTLV-1-infected cells, preventing the recurrence of various symptoms caused by improved HAM, or preventing the onset of HAM in asymptomatic HTLV-1-infected individuals.

[0095] The therapeutic or prophylactic agent of this embodiment contains a substance that suppresses the proliferation of plasma cells, and may further contain a pharmaceutically acceptable carrier and / or additive. The blending ratio of the carrier or additive may be appropriately set based on the range commonly used in the pharmaceutical field. The carrier is not particularly limited, but examples thereof include water, physiological saline, other aqueous solvents, and aqueous or oily bases. The additives are not particularly limited, but examples thereof include excipients, binders, pH adjusters, disintegrants, absorption enhancers, lubricants, colorants, flavoring agents, and fragrances.

[0096] The form of the therapeutic or prophylactic agent is not particularly limited, and examples thereof include oral preparations such as tablets, coated tablets, pills, powders, granules, capsules, liquids, suspensions, and emulsions, and parenteral preparations such as injections, infusions, suppositories, ointments, and patches.

[0097] The method of administration of the therapeutic or prophylactic agent is not particularly limited, but is preferably administered as an injection or infusion via a parenteral administration route, for example, intravenously, intramuscularly, intradermally, intraperitoneally, subcutaneously, or topically, and more preferably topically. Injectables or infusions containing substances that suppress the proliferation of plasma cells can be used as solutions, suspensions, or emulsions. Examples of solvents include distilled water for injection, physiological saline, glucose solutions, and isotonic solutions (e.g., solutions of sodium chloride, potassium chloride, glycerin, mannitol, sorbitol, boric acid, borax, propylene glycol, etc.). These solvents may be used alone or in combination of two or more.

[0098] Furthermore, the injection or infusion may contain additives such as stabilizers, solubilizers, suspending agents, emulsifiers, soothing agents, buffers, preservatives, antiseptics, and pH adjusters. The stabilizer is not particularly limited, but examples thereof include albumin, globulin, gelatin, mannitol, glucose, dextran, ethylene glycol, propylene glycol, ascorbic acid, sodium bisulfite, sodium thiosulfate, sodium EDTA, sodium citrate, and dibutylhydroxytoluene. The solubilizing agent is not particularly limited, but examples thereof include alcohols (e.g., ethanol, etc.), polyalcohols (e.g., propylene glycol, polyethylene glycol, etc.), nonionic surfactants (e.g., Polysorbate 80 (registered trademark), HCO-50, etc.), etc. The suspending agent is not particularly limited, but examples thereof include glycerin monostearate, aluminum monostearate, methylcellulose, carboxymethylcellulose, hydroxymethylcellulose, sodium lauryl sulfate, and the like. The emulsifier is not particularly limited, but examples thereof include gum arabic, sodium alginate, and tragacanth. The soothing agent is not particularly limited, but examples thereof include benzyl alcohol, chlorobutanol, sorbitol, and the like. The buffer is not particularly limited, but examples thereof include phosphate buffer, acetate buffer, borate buffer, carbonate buffer, citrate buffer, Tris buffer, and the like. The preservative is not particularly limited, but examples thereof include methyl parahydroxybenzoate, ethyl parahydroxybenzoate, propyl parahydroxybenzoate, butyl parahydroxybenzoate, chlorobutanol, benzyl alcohol, benzalkonium chloride, sodium dehydroacetate, sodium edetate, boric acid, and borax. The preservative is not particularly limited, but examples thereof include benzalkonium chloride, parahydroxybenzoic acid, chlorobutanol, and the like. The pH adjuster is not particularly limited, but examples thereof include hydrochloric acid, sodium hydroxide, phosphoric acid, and acetic acid.

[0099] The dosage and administration interval of the active ingredient of the therapeutic or prophylactic agent of this embodiment can be appropriately selected depending on the subject to be administered, the administration route, the disease, and the age, weight, and symptoms of the subject. For example, in the case of oral administration, the daily dose of the active ingredient for an adult is, but is not particularly limited to, 0.01 mg to 10 g, or may be 100 mg to 6 g, or may be 50 mg to 500 mg. The administration interval of the therapeutic or prophylactic agent may be such that the daily dose is administered once a day, or may be administered in divided doses several times a day.

[0100] The subject to which the therapeutic or prophylactic agent of this embodiment is administered is a mammal. Mammals are not particularly limited, but include, for example, humans, non-human primates, domestic animals, laboratory animals, and livestock, and are preferably humans.

[0101] The therapeutic or preventive agent of this embodiment may be administered in combination with one or more other agents. Examples of other agents include, but are not limited to, known HAM therapeutic agents. Examples of existing HAM therapeutic agents include, but are not limited to, interferon α, mogamulizumab, teriflunomide, and humanized anti-RGMa antibodies.

[0102] In the combined administration, the therapeutic or prophylactic agent of this embodiment and the other agent may be administered at different times. When administered simultaneously, two or more active ingredients may be in the same formulation, or may be administered as separate formulations. When administered at separate times, the two or more active ingredients may be administered according to the desired administration regimen, with the dosage and interval of the other active ingredient being in accordance with the prescribed administration regimen.

[0103] It has been found that peripheral blood mononuclear cells (PBMCs) from HAM patients spontaneously proliferate when cultured under unstimulated conditions due to the proliferation of HTLV-1-infected cells and the immune cell response thereto. This phenomenon is known as a useful model reflecting the pathology of HAM. Therefore, in one aspect, the therapeutic or prophylactic agent of this embodiment can inhibit the spontaneous proliferation activity of HTLV-1-infected T cells. In one aspect, the therapeutic or prophylactic agent of this embodiment can suppress the spontaneous proliferation activity of HTLV-1-infected T cells. In one aspect, the therapeutic or prophylactic agent of this embodiment can suppress HAM-specific inflammatory conditions.

[0104] In any of the above embodiments described herein, the substance that suppresses the proliferation of plasma cells may be any of the aspects described herein, as well as the aspects described herein as preferred, more preferred, and particularly preferred (all of these aspects are hereinafter collectively referred to as "preferred aspects"), or any combination of preferred aspects. [Example]

[0105] Some examples of the above-described embodiments of the present invention are described below. However, the present invention is not limited to these examples.

[0106] [Example 1: Gene expression profile analysis of HAM lesion area] We performed spatial transcriptome analysis of the HAM lesion area, analysis of gene expression profiles of the HAM lesion area, and comparative analysis of the HAM lesion area and its counterpart area in healthy individuals.

[0107] (Spatial transcriptome analysis of HAM lesion areas) Spatial transcriptome analysis was performed as follows. Five thin sections containing the lesion area were prepared from paraffin-embedded autopsy thoracic spinal cord samples from three HAM patients. Following the protocol of the Visium Spatial Gene Expression for FFPE Reagent Kits (10X GENOMICS), the thin sections were deparaffinized and stained with hematoxylin-eosin (HE). High-resolution images of the HE-stained sections were captured using an all-in-one fluorescence microscope (Olympus). As a control experiment, one thin section was prepared from the paraffin-embedded autopsy thoracic spinal cord samples from a healthy individual and processed in the same way. After destaining with HE, formaldehyde cross-linking was performed. Probes designed to cover all genes (Human WT Probes v2-RHS and Human WT Probes v2-LHS, both 10X GENOMICS) were added to the thin sections and incubated at 50°C for 24 hours. Each probe was designed to be positioned adjacent to a specific region of mRNA, and only probes that were successfully ligated by ligase could proceed to the next reaction. Using a Visium CytAssist (10X GENOMICS), the ligated probes within the cells in the thin sections were transferred to a Visium slide (10X GENOMICS). The Visium slide contained 5,000 spots (6.5 mm square) with 55 μm diameter spots containing base sequences consisting of base barcodes and unique molecular identifiers (UMIs) for spatial information. The ligated probes bound to the base sequences within the spots during transfer to the Visium slide, and an extension reaction added the spatial information and UMIs. This process purified the library. The library was then sequenced using a NovaSeq6000 (Illumina) with adapters (Dual Index Plate TS Set A, 10X GENOMICS) attached to both ends.

[0108] (Analysis of gene expression profiles in HAM lesion areas) Gene expression profiles in the HAM lesion area were analyzed as follows. The sequence data obtained by sequencing were analyzed (sequence read mapping and alignment) using the Space Ranger (10X GENOMICS) analysis software pipeline on the SHIROKANE supercomputer (Institute of Medical Science, University of Tokyo). This analysis yielded spot-by-sequence gene expression and spatial information for 15,484 spots on the Visium slide. The data were integrated using Seurat (https: / / satijalab.org / seurat / ), an R package for single-cell RNA-seq analysis, and then clustered using Uniform Manifold Approximation and Projection (UMAP). Analysis of the stained images of healthy subjects revealed clusters 0 and 1 distributed throughout the white matter, while analysis of HAM patients revealed cluster 5 distributed in the anterior and lateral funiculus. Figure 1 shows the localization of each cluster (clusters 0, 1, and 5) superimposed on the HE stained image (top: healthy subject; bottom: HAM patient).

[0109] (Comparative analysis of HAM lesion areas and their counterpart areas in healthy individuals) Comparative analysis of HAM lesions and their counterparts in healthy controls was performed as follows. Using Seurat, gene expression profiles of cluster 5 were compared with clusters 0 and 1. Table 4 shows the genes with the greatest variation in cluster 5 compared with clusters 0 and 1. From left to right, the gene name, Log2 fold change, and adjacent p-value are shown. Figure 2 also shows a plot of gene expression levels (IGKC, IGHG1, MZB1, SDC1, and MS4A1) at each spot on a thin section based on HE staining. In the figure, red indicates high values, and blue indicates low values ​​or values ​​below the detection limit (top row: healthy controls; middle row: acute-phase HAM patients; bottom row: chronic-phase HAM patients). (Plasma cell-related genes were upregulated in the HAM lesions (particularly the anterior and lateral columns).)

[0110] [Table 5]

[0111] As shown in Figure 2, plasma cell markers were distributed in large quantities in the HAM lesions. These findings demonstrate that plasma cells infiltrate in large quantities in the HAM lesions.

[0112] Example 2: Depletion of B cells and plasma cells in a spontaneous proliferation model of PBMCs from HAM patients To confirm the effectiveness of depletion of B cells and plasma cells in treating HAM, the following experiment was carried out.

[0113] B cells (CD20) in PBMCs from HAM patients + ) removal) HAM patient PBMC 1×10 7 20 μl of CD20 MicroBeads (Miltenyi Biotec) solution was added to the cells, and negative selection of CD20-positive cells was performed using a QuadroMACS Separator and an LD column (both Miltenyi Biotec). PBMCs from which CD20-positive cells had been removed were placed in a 96-well U bottom dish (Falcon) at 2 × 10 5 Cells were cultured at a cell density of 200 μl in RPMI 1640 medium containing 10% fetal bovine serum (FBS) and antibiotics (1% penicillin-streptomycin) for 7 days. PBMCs before sorting were used as a control sample. After 7 days, cell proliferation was measured using the CellTiter-Blue Cell Viability Assay (Promega) on a Varioskan LUX multimode microplate reader (ThermoFisher Scientific). The results and the average values ​​of the results for the four HAM patients are shown as a bar graph in Figure 3. Statistical significance was evaluated by paired t-test. ** indicates P < 0.01.

[0114] B cells (CD19) in PBMCs from HAM patients + ) removal) HAM patient PBMC 1×10 7 20 μl of CD19 MicroBeads (Miltenyi Biotec) solution was added to the cells, and negative selection of CD19-positive cells was performed using a QuadroMACS Separator and an LD column (both Miltenyi Biotec). PBMCs from which CD19-positive cells had been removed were placed in a 96-well U bottom dish (Falcon) at 2 × 10 5 Cells were cultured at a cell density of 200 μl in RPMI 1640 medium containing 10% FBS and antibiotics (1% penicillin-streptomycin) for 7 days. PBMCs before sorting were used as a control sample. After 7 days, cell proliferation was measured using the CellTiter-Blue Cell Viability Assay (Promega) on a Varioskan LUX multimode microplate reader (ThermoFisher Scientific). The results and the average values ​​of the results for the three HAM patients are shown as a bar graph in Figure 4. Statistical significance was evaluated by paired t-test.

[0115] B cells (CD19) in PBMCs from HAM patients using anti-CD19 antibody (inebilizumab) + ) removal) PBMCs from HAM patients were cultured in a 96-well U-bottom dish (Falcon) at 2 × 10 5Cells were cultured at a cell density of 200 μl in RPMI 1640 medium containing 10% FBS, antibiotics (1% penicillin-streptomycin), and inebilizumab for 7 days. The final inebilizumab concentration was adjusted to 0.1, 1, or 10 μg / ml. Controls included the addition of an equal volume of PBS as the solvent. After 7 days, cell proliferation was measured using the CellTiter-Blue Cell Viability Assay (Promega) on a Varioskan LUX multimode microplate reader (ThermoFisher Scientific). The results of the eight HAM patients are shown as a bar graph in Figure 5 (left). Statistical significance was evaluated by paired t-test (Figure 5 right). ** indicates P < 0.01.

[0116] (B cells (CD20) in PBMCs of HAM patients using anti-CD20 antibody (Ofatumumab) + ) removal) PBMCs from HAM patients were cultured in a 96-well U-bottom dish (Falcon) at 2 × 10 5 Cells were cultured at a cell density of 200 μl in RPMI 1640 medium containing 10% FBS, antibiotics (1% penicillin-streptomycin), and ofatumumab for 7 days. The final concentration of ofatumumab was adjusted to 0.1 or 1 μg / ml. Controls included the addition of an equal volume of PBS as the solvent. After 7 days, cell proliferation was measured using the CellTiter-Blue Cell Viability Assay (Promega) on a Varioskan LUX multimode microplate reader (ThermoFisher Scientific). The results of the four HAM patients are shown as a bar graph in Figure 6 (left). Statistical significance was evaluated by paired t-test (Figure 6 right). ** indicates P < 0.01.

[0117] CD38 in PBMCs from HAM patients using anti-CD38 antibody (Daratumumab) + Cell removal) PBMCs from HAM patients were cultured in a 96-well U-bottom dish (Falcon) at 2 × 10 5 Cells were cultured at a cell density of 200 μl in RPMI 1640 medium containing 10% FBS, antibiotics (1% penicillin-streptomycin), and daratumumab for 7 days. The final concentration of daratumumab was adjusted to 0.1, 1, or 10 μg / ml. Controls included the addition of an equal volume of daratumumab in PBS. After 7 days, cell proliferation was measured using the CellTiter-Blue Cell Viability Assay (Promega) on a Varioskan LUX multimode microplate reader (ThermoFisher Scientific). The results of the eight HAM patients are shown as a bar graph in Figure 7 (left). Statistical significance was evaluated by paired t-test (Figure 7 right). ** indicates P < 0.01.

[0118] These results suggest that the proliferation of PBMCs from HAM patients can be suppressed by removing at least one type of cell selected from the group consisting of B cells and plasma cells, i.e., by suppressing the increase of plasma cells. Note that all of the antibodies used above exhibit ADCC activity.

[0119] Example 3: BTK inhibition in a spontaneous proliferation model of PBMCs from HAM patients PBMCs from HAM patients were cultured in a 96-well U-bottom dish (Falcon) at 2 × 10 5Cells were cultured at a cell density of 200 μl in RPMI 1640 medium containing 10% FBS, antibiotics (1% penicillin-streptomycin), and BTK inhibitors (fenebrutinib or tolebrutinib) for 7 days. The final concentration of the BTK inhibitor was adjusted to 100 nM. Controls were prepared by adding the solvent, DMSO, in an equal volume to the BTK inhibitor. After 7 days, cell proliferation was measured using the CellTiter-Blue Cell Viability Assay (Promega) on a Varioskan LUX multimode microplate reader (ThermoFisher Scientific). The results for the 12 HAM patients are shown as bar graphs in Figure 8 (left: fenebrutinib, right: tolebrutinib). Statistical significance was assessed by paired t-test (bottom panel of Figure 8). * indicates P < 0.05. These findings suggest that inhibiting the differentiation of B cells into plasma cells, i.e., suppressing the increase in plasma cells, suppresses cell proliferation in PBMCs from HAM patients.

Claims

1. A therapeutic or preventive agent for HTLV-1 associated myelopathy (HAM), comprising a substance that suppresses the proliferation of plasma cells.

2. The substance is (A) an antibody or antibody fragment thereof that binds to a protein expressed on the surface of at least one of B cells and plasma cells; (B) a cell genetically modified to express a chimeric antigen receptor that binds to a protein expressed on the surface of at least one of B cells and plasma cells; and (C) A differentiation inhibitor that inhibits the differentiation of B cells into plasma cells At least one of The therapeutic or prophylactic agent according to claim 1.

3. the substance comprises the antibody (A) or an antibody fragment thereof, and the antibody (A) or an antibody fragment thereof has ADCC activity, CDC activity, or ADCP activity; The therapeutic or prophylactic agent according to claim 2.

4. the expressed protein is at least one of CD19, CD20, CD27, CD38, and CD138; The therapeutic or prophylactic agent according to claim 2.

5. the expressed protein is at least one of CD19, CD27, CD38, and CD138; The therapeutic or prophylactic agent according to claim 2.

6. the expressed protein is at least one of CD27, CD38, and CD138; The therapeutic or prophylactic agent according to claim 2.

7. the expressed protein is at least one of CD19, CD20, and CD38; The therapeutic or prophylactic agent according to claim 2.

8. (C) The differentiation inhibitor is a Bruton's tyrosine kinase (BTK) inhibitor. The therapeutic or prophylactic agent according to claim 2.

9. The substance suppresses the increase of plasma cells in the white matter region of the spinal cord. The therapeutic or prophylactic agent according to any one of claims 1 to 8.

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