Anti-BSSL antibodies for the treatment of cancer

Abstract

The present invention relates to an antibody or antigen-binding fragment thereof that specifically binds to bile salt-stimulated lipase (BSSL), and is used to treat a BSSL-expressing cancer in a subject. The antibody or antigen-binding fragment thereof binds to an epitope present in the N-terminal portion of BSSL, ranging from the N-terminus of BSSL to amino acid residue 300 of BSSL (excluding the active site of BSSL).

Description

[Technical Field]

[0001] The present invention relates to cancer treatment and in particular to the use of anti-BBSL antibodies in such cancer treatment. [Background technology]

[0002] Bile salt-stimulated lipase (BSSL), also known as bile salt-dependent lipase (BSDL), carboxylester lipase (CEL), or bile salt-activated lipase (BAL), is a lipolytic enzyme encoded by the CEL gene. In all animal species studied to date, BSSL is expressed in the exocrine pancreas and secreted into the intestinal lumen to aid in the digestion of lipids.

[0003] In some species, including humans, primates, dogs, cats, and mice, BSSL is expressed in the lactating mammary gland and secreted into milk. Furthermore, BSSL is present at low but significant levels in the serum of healthy individuals and has been shown to be involved in the regulation of lipoprotein metabolism and atherosclerosis. BSSL has also been shown to play a role in inflammatory processes.

[0004] In Cancer Genetics 2019, 239:54-61, we investigated the correlation between BSSL expression in breast cancer tissue and breast cancer patient survival by analyzing Cancer Genome Atlas Breast Carcinoma (TCGA-BFCA) level 3 data. Analysis of tumor data from 1,104 cases demonstrated that BSSL is overexpressed in breast cancer. High BSSL expression was associated with clinicopathological features. Patients with high BSSL expression had a lower survival rate. Analysis of the receiver operating characteristic (ROC) area under the curve (AUC) for BSSL revealed limited diagnostic power.

[0005] U.S. Patent Nos. 7,557,193 and 8,367,062 disclose glycopeptides containing 1-40 repeats of the C-terminal polypeptide of 11 amino acids (J28 peptide) of BSDL or human fetal pancreatic protein (FAPP). The repeats of the C-terminal polypeptide are glycosylated and contain a glycosylated epitope that elicits a specific immune response by inducing antibodies in patients with type 1 diabetes.

[0006] US Patent Application No. 2010 / 0124555 discloses methods of making antigen-binding compounds suitable for use in the treatment of cancer, the antigen-binding compounds, and uses thereof.

[0007] There remains a need for treatments for cancer, and in particular for treatments for BSSL-expressing cancers. Summary of the Invention

[0008] It is a general objective to provide a treatment for BSSL-expressing cancers.

[0009] The embodiments disclosed herein are capable of meeting these and other objectives.

[0010] The invention is defined by the independent claims. Further embodiments of the invention are defined by the dependent claims.

[0011] One aspect of the present invention relates to an antibody or antigen-binding fragment thereof that specifically binds to BSSL and is used to treat a BSSL-expressing cancer in a subject. The antibody or antigen-binding fragment thereof binds to an epitope present in the N-terminal portion of BSSL (ranging from the N-terminus of BSSL to amino acid residue 300 of BSSL, excluding the active site of BSSL).

[0012] The present invention relates to an antibody or antigen-binding fragment thereof that binds to the N-terminal portion of BSSL. Such an antibody or antigen-binding fragment thereof can reduce the size of primary tumors in BSSL-expressing cancers and can also have the effect of inhibiting metastasis of such primary tumors. A major advantage of this antibody or antigen-binding fragment thereof is that it does not bind to the active site of BSSL and therefore does not inhibit the enzymatic activity of BSSL. Therefore, side effects associated with inhibition of BSSL activity are avoided or at least reduced.

[0013] The embodiments, together with further objects and advantages thereof, will be better understood by reference to the accompanying drawings and the following description. [Brief explanation of the drawings]

[0014] [Figure 1] Normalization of primary tumor growth data and normalization of metastases for all cell lines when treated with SOL-116 compared to the human IgG4 S241P isotype control are shown. Data are shown as mean ± standard error; two-tailed Student's t-test, **p<0.01. [Figure 2] Figure 1 shows the effect of SOL-116 on LXFS-1129 primary tumor size and metastasis. Data are shown as mean ± standard error; two-tailed Student's t-test, *p<0.05 and **p<0.01. [Figure 3] Figure 1 shows the effect of SOL-116 on CXF-1788 primary tumor size and metastasis. Data are shown as mean ± standard error; two-tailed Student's t-test, *p<0.05. [Figure 4] Figure 1 shows the effect of SOL-116 on the size and metastasis of CXF-158 primary tumors. Data are shown as mean ± standard error; two-tailed Student's t-test, *p<0.05. [Figure 5] Figure 1 shows the effect of SOL-116 on LXFS-2156 primary tumor size and metastasis. Data are shown as mean ± standard error; two-tailed Student's t-test, *p<0.05. [Figure 6]Figure 1 shows the effect of SOL-116 on CXF-2836 primary tumor size and metastasis. Data are shown as mean ± standard error; two-tailed Student's t-test, **p<0.01. [Figure 7] Figure 1 shows the effect of SOL-116 on CXF-533 primary tumor size and metastasis. Data are shown as mean ± standard error. [Figure 8] 1 shows the effect of anti-BSSL antibodies on the size and metastasis of LXFS-1129 primary tumors. Data are shown as mean ± standard error. One-way analysis of variance (p=0.0009) followed by two-tailed Student's t-test; *p<0.05, **p<0.01, and ***p<0.001. [Figure 9] 1 shows the effect of anti-BSSL antibodies on the size of LXFS-1129 primary tumors. The negative control and SOL-116 data from Example 2 were combined with the negative control and SOL-116 data obtained in Example 3. Data are shown as mean ± standard error. One-way ANOVA (p=0.0003) followed by two-tailed Student's t-test; *p<0.05, **p<0.01, ***p<0.001, and ****p<0.0001. [Figure 10] Figure 1 shows the effect of anti-BSSL antibodies on the size and metastasis of CXF-158 primary tumors. Data are shown as mean ± standard error. One-way analysis of variance (p=0.0259) followed by two-tailed Student's t-test; *p<0.05. [Figure 11] 1 shows the effect of anti-BSSL antibodies on the size of CXF-158 primary tumors. The negative control and SOL-116 data from Example 2 were combined with the negative control and SOL-116 data obtained in Example 3. Data are shown as mean ± standard error. One-way ANOVA (p=0.0013) followed by two-tailed Student's t-test; *p<0.05, **p<0.01, and ***p<0.001. [Figure 12] Figure 1 shows the effect of anti-BSSL antibodies on LXFS-2156 primary tumor size and metastasis. Data are shown as mean ± standard error. One-way ANOVA (p=0.0088) followed by two-tailed Student's t-test; *p<0.05 and **p<0.01. [Figure 13]1 shows the effect of anti-BSSL antibodies on the size of LXFS-2156 primary tumors. The negative control and SOL-116 data from Example 2 were combined with the negative control and SOL-116 data obtained in Example 3. Data are presented as mean ± standard error. [Figure 14] 1 shows the effect of anti-BSSL antibodies on CXF-533 primary tumor size and metastasis. Data are shown as mean ± standard error. [Figure 15] 1 shows the effect of anti-BSSL antibodies on the size of CXF-533 primary tumors. The negative control and SOL-116 data from Example 2 were combined with the negative control and SOL-116 data obtained in Example 3. Data are presented as mean ± standard error. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention relates to cancer treatment and in particular to the use of anti-BBSL antibodies in such cancer treatment.

[0016] definition The term "isolated" when used in connection with an antibody or antigen-binding fragment thereof means that the antibody or antigen-binding fragment thereof has been removed from its original environment. An isolated antibody or isolated antigen-binding fragment thereof is intended to refer to an antibody or antigen-binding fragment thereof that is substantially free of other antibodies or antigen-binding fragments thereof with different antigen specificities. Thus, an isolated antibody or antigen-binding fragment thereof that specifically binds to BSSL, particularly human BSSL (hBSSL), is substantially free of antibodies or antigen-binding fragments thereof that specifically bind to antigens other than BSSL, particularly antigens other than hBSSL. However, an isolated antibody or antigen-binding fragment thereof that specifically binds to hBSSL may have cross-reactivity with other antigens, such as BSSL molecules from other species (e.g., murine BSSL (mBSSL) from mouse). Furthermore, an isolated antibody or antigen-binding fragment thereof may be substantially free of other cellular components and / or chemicals. For example, the isolated antibody or antigen-binding fragment thereof can be purified to greater than 95% or 99% purity, as determined, for example, by electrophoresis (e.g., sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), isoelectric focusing (IEF), capillary electrophoresis), or chromatography (e.g., ion exchange or affinity chromatography). As used herein, the term "antibody or antigen-binding fragment thereof" should be understood to refer to an isolated antibody or antigen-binding fragment thereof, even if the term "isolated" is not explicitly used in each instance.

[0017] The term "antigen-binding fragment" refers to a fragment or portion of an antibody that substantially retains antigen-binding properties. An antigen-binding fragment is a portion or region of an antibody molecule that retains all or most of the antigen-binding properties of the corresponding intact antibody. An antigen-binding fragment may comprise one or more complementarity-determining region (CDR) sequences of the antibody or portions of these CDR sequences, a portion or the entire heavy chain variable region (HCVR), a portion or the entire light chain variable region (LCVR), or a combination thereof. In one embodiment, an antigen-binding fragment of an antibody may consist of a contiguous amino acid sequence of the antibody obtained from the antibody, or may consist of different portions of the antibody amino acid sequence linked together with or without a linker. Examples of antigen-binding fragments include single-chain variable fragments (scFv), Fab fragments, F(ab')2 fragments, F(ab')3 fragments, Fab' fragments, Fv fragments, dAb fragments, isolated complementarity-determining regions (CDRs), and nanobodies.

[0018] A "single-chain variable fragment" ("scFv") is a fusion protein of the variable regions of an immunoglobulin heavy chain and a light chain, typically linked by a short linker peptide of about 10 to 25 amino acids. The same or different scFvs (having affinity for the same or different epitopes) may be combined in different combinations known to those skilled in the art. Non-limiting examples of such combinations include tandem di-scFvs, bispecific antibodies, tandem tri-scFvs, or tri(a)bodies.

[0019] The term "epitope" refers to the portion of an antigen that is recognized by the immune system (such as by an antibody or antigen-binding fragment thereof). Epitopes are also called antigenic determinants.

[0020] As used herein, the terms "binds to," "has affinity for," "affinity," and the like refer to the property of an antibody or antigen-binding fragment thereof binding to a target molecule. Standard assays for assessing the binding ability of an antibody or antigen-binding fragment to a target molecule include, for example, enzyme immunoassays (EIAs) (such as enzyme-linked immunosorbent assays (ELISAs)), Western blots, radioimmunoassays (RIAs), surface plasmon resonance (SPR), LUMINEX® Multiplex assays, and flow cytometry analysis.

[0021] "Specifically binds to," "specifically binding to," and the like mean that the antibody or antigen-binding fragment thereof selectively binds to the target antigen but does not exhibit biologically relevant binding to other molecules. The specificity of an antibody or antigen-binding fragment thereof can be determined based on affinity and / or avidity. The dissociation equilibrium constant (K) between an antigen and an antibody or antigen-binding fragment thereof is D Affinity, expressed as K), is a measure of the binding strength between an antigen-binding site on the antibody or antigen-binding fragment thereof and an antigenic determinant (i.e., epitope). D The lower the value, the stronger the binding strength between the antibody or antigen-binding fragment thereof and the antigenic determinant. Alternatively, affinity can be expressed as an affinity constant (K A ) can also be expressed as (K A =1 / K D As will be apparent to those skilled in the art, affinity can be determined by known methods, essentially depending on the specific antigen of interest. Typically, an antibody or antigen-binding fragment thereof binds to a corresponding antigen, but its dissociation equilibrium constant (K D ) is 10 -5 ~10 -12 moles / liter (M) or less, and preferably 10 -7 ~10 -12 M or less, and more preferably 10 -8 ~10 -12M; i.e., its affinity constant (K A ) is 10 5 ~10 12 M -1 or more, and preferably 10 7 ~10 12 M -1 or more, and more preferably 10 8 ~10 12 M -1 Generally, 10 -4 Any K greater than M D value (or 10 4 M -1 Any lower K A A value of 0.05 (or 0.15) indicates non-selective binding; i.e., is considered to lack specificity for the antigen. Preferably, antibodies or antigen-binding fragments thereof of the embodiments bind to BSSL with a dissociation constant of less than 500 nM, preferably less than 200 nM, and more preferably less than 10 nM (e.g., less than 5 nM).

[0022] As used herein, all amino acids in the variable regions, including the CDRs described herein, are numbered according to the IMGT specific numbering system defined by Marie-Paule Lefranc (Developmental and Comparative Immunology (2003) 27(1):55-77).

[0023] Certain cancer types, including breast and pancreatic cancers, are known to express BSSL. In particular, BSSL has been used primarily as a biomarker for patient stratification and prognosis. High BSSL expression, in particular, has been associated with poor survival in breast cancer patients.

[0024] U.S. Patent Nos. 7,557,193 and 8,367,062 investigated the efficacy of monoclonal IgM antibody 16D10 (mAb 16D10) in treating exocrine pancreatic cancer. mAb 16D10 targets a glycosylated epitope specifically expressed in the C-terminal domains of FAPP and BSDL. mAb 16D10 slowed tumor growth and reduced median tumor volume compared with controls. U.S. Patent Application No. 2010 / 0124555 compared mAb 16D10 with the murine monoclonal antibody mAb J28, specific for the fucosylated J28 glycopeptide derived from O-glycosylation of oncofetal FAPP, and the anti-BSDL polyclonal antibody pAbL64 in a pancreatic tumor model. mAb J28 is said to bind to an epitope on BDSL and / or FAPP that is distinct from the epitope recognized by mAb 16D10. Although the antibodies mAb 16D10, mAb J28, and pAbL64 all target BDSL and / or FAPP, only mAb 16D10 was able to reduce pancreatic tumor cell proliferation, whereas mAb J28 and pAbL64 had no such effect. In conclusion, the ability of monoclonal antibodies to stimulate apoptotic cell death in pancreatic cancer cells was dependent on the localization of the antigen recognized by mAb 16D10 in membrane lipid raft microdomains.

[0025] The present invention is based on the discovery that specific anti-BSSL antibodies or antigen-binding fragments thereof targeting the N-terminal portion of BSSL are useful for treating BSSL-expressing cancers. However, these anti-BSSL antibodies did not have a significant effect on cancer types that do not express BSSL or express it at low levels. This suggests that BSSL is useful not only as a biomarker for predicting patient survival but also as a target for the treatment of BSSL-expressing cancers. Given that BSSL has no known effect on cancer cells and is simply recognized as a lipolytic enzyme (EC 3.1.1) that hydrolyzes dietary fats, cholesteryl esters, and fat-soluble vitamins in the duodenum, the above-mentioned effects of anti-BSSL antibodies were quite unexpected.

[0026] Compared with the monoclonal antibody mAb 16D10, which has been disclosed to be effective in inducing apoptosis in exocrine pancreatic cancer cells, the antibody or antigen-binding fragment of the present invention binds to a different epitope on BSSL. This monoclonal antibody mAb 16D10 is said to bind to the glycosylated C-terminal portion of BSDL / FAPP. Binding of mAb 16D10 to this glycosylated C-terminal portion of BSDL / FAPP induces apoptosis in exocrine pancreatic cancer cells through activation of caspase-3, caspase-8, and caspase-9 and cleavage of poly (ADP-ribose) polymerase (PARP). This means that for mAb 16D10 to be effective, the cancer cells must express not only BSDL / FAPP but also caspase-3, caspase-8, and / or caspase-9, and PARP.

[0027] The antibodies or antigen-binding fragments thereof of the present invention specifically bind to an epitope present in the N-terminal portion of BSSL, which extends from the N-terminus of BSSL to amino acid residue 300 of BSSL, but excluding the active site of BSSL.

[0028] Thus, one aspect of the present invention relates to an antibody or antigen-binding fragment thereof that specifically binds to BSSL, and is used to treat a BSSL-expressing cancer in a subject. The antibody or antigen-binding fragment thereof binds to an epitope present in the N-terminal portion of BSSL (ranging from the N-terminus of BSSL to the amino acid residues of BSSL, but excluding the active site of BSSL).

[0029] Human BSSL consists of 722 amino acid residues (SEQ ID NO: 46), with a highly glycosylated C-terminal portion containing 16 proline-rich repeats of 11 residues, including O-linked glycans. The catalytic triad in the active site of BSSL consists of serine at position 194 (Ser194), aspartic acid at position 320 (Asp320), and histidine at position 435 (His435) (Protein Science (1997) 6:73-79; Journal of Molecular Biology (2001) 312(3):511-523). Upon expression, human BSSL initially contains a 20-amino acid signal peptide that is cleaved upon secretion of the protein. References to amino acid positions herein refer to the amino acid positions in the mature human BSSL protein after signal peptide cleavage (i.e., SEQ ID NO: 46). Since human BSSL contains up to 17 proline-rich repeat units in its C-terminal portion, in this case the length of human BSSL is 733 amino acid residues (UniProt accession number: P19835). However, references to human BSSL and amino acid residues of human BSSL herein are based on the amino acid sequence of SEQ ID NO: 46. However, the antibodies or antigen-binding fragments thereof disclosed herein also specifically bind to other forms of human BSSL.

[0030] Thus, in one embodiment, the antibody or antigen-binding fragment thereof binds to an epitope comprising amino acids within the N-terminal portion of BSSL (ranging from the N-terminus of SEQ ID NO:46 to and including amino acid residue 300 of BSSL, but excluding amino acid residue 194 (and amino acid residues 320 and 435) of SEQ ID NO:46).

[0031] Thus, the antibody or antigen-binding fragment thereof of the present invention binds to the outside of the active site of BSSL. Accordingly, in one embodiment, the antibody or antigen-binding fragment thereof does not affect the lipase enzymatic activity of BSSL. As used herein, "does not affect the lipase enzymatic activity" of BSSL means that the lipase activity of the BSSL enzyme to which the antibody or antigen-binding fragment thereof of the present invention is bound is at least 80% of the lipase activity of the BSSL enzyme when the antibody or antigen-binding fragment thereof is not bound. In particular, the lipase activity of the BSSL to which the antibody or antigen-binding fragment thereof of the present invention is bound is preferably at least 85%, and more preferably at least 90% (such as at least 95% or more, such as at least 96%, at least 97%, at least 98%, or at least 99%) of the lipase activity of the BSSL enzyme when the antibody or antigen-binding fragment thereof is not bound.

[0032] The epitope to which the antibody or antigen-binding fragment thereof of the present invention binds is located in the N-terminal portion of BSSL and is not present in the active site of BSSL, which has the advantage that the antibody or antigen-binding fragment thereof does not significantly affect the lipase enzymatic activity of BSSL, and therefore the antibody or antigen-binding fragment thereof is unlikely to cause negative side effects.

[0033] The BSSL structure has been reported to have a large core region consisting of a twisted 11-stranded β-sheet surrounded by alpha helices and connecting loops. At its N-terminus is a smaller, three-stranded β-sheet. The structure has been described using the metaphor of a left-hand oven glove, with the palm of the hand positioned near the "thumb" and the three active site residues. In this metaphor, the small N-terminal β-sheet is located on the dorsum of the hand near the "pinky finger." The portion of the BSSL structure that interacts with the antibody or antigen-binding fragment thereof is located C-terminal to the small N-terminal β-sheet and alpha C (the third alpha helix in the structure). In other words, the region to which the antibody or antigen-binding fragment binds is not near the active site of the BSSL, but is located on the opposite side of the active site in the BSSL.

[0034] In one embodiment, the antibody or antigen-binding fragment thereof binds to an epitope of BSSL comprising amino acid residues 7-12 (strands 1 and 2 of the β-sheet; SEQ ID NO: 1) and amino acid residues 42-55 (the loop region leading to strand 3 of the β-sheet; SEQ ID NO: 2). The epitope is fairly flat, with only a few prominent characteristic residues (i.e., Tyr7, Phe12, and Gln52). The loop region from 47 to 55 has a well-defined, uniform surface. Proline 47 is important for stacking interactions with Tyr31 of the antibody or antigen-binding fragment thereof, but the overall surface is flat. Thus, in one embodiment, the antibody or antigen-binding fragment thereof comprises: a first surface comprising or defined by the amino acid sequence of SEQ ID NO: 1; and a second surface comprising or defined by the amino acid sequence of SEQ ID NO: 2; In one specific embodiment, the first surface comprises or is defined by the amino acid sequence of SEQ ID NO:3, which corresponds to amino acid residues 1-12 of hBSSL.

[0035] In one embodiment, the antibody or antigen-binding fragment thereof may specifically bind to an additional surface, i.e., a third surface, of the BSSL (such as a hBSSL). In one embodiment, this third surface comprises: the amino acid sequence of SEQ ID NO: 4, corresponding to amino acid residues 84 to 101 of hBSSL; the amino acid sequence of SEQ ID NO: 5, corresponding to amino acid residues 174 to 180 of hBSSL; or the amino acid sequence of SEQ ID NO: 6, corresponding to amino acid residues 283 to 294 of hBSSL; Including or as defined by the same.

[0036] In one embodiment, the antibody or antigen-binding fragment thereof: a first peptide comprising SEQ ID NO:1 (e.g., a first peptide consisting of SEQ ID NO:1); a second peptide comprising (e.g., consisting of) SEQ ID NO:2; and a third peptide comprising SEQ ID NO: 4 (such as a peptide consisting of SEQ ID NO: 4); Alternatively, such an antibody or antigen-binding fragment thereof may bind to the longer amino acid sequence according to SEQ ID NO:3 instead of binding to the shorter amino acid sequence according to SEQ ID NO:1.

[0037] In another embodiment, the antibody or antigen-binding fragment thereof: a first peptide comprising SEQ ID NO:1 (e.g., a first peptide consisting of SEQ ID NO:1); a second peptide comprising SEQ ID NO:2 (such as a second peptide consisting of SEQ ID NO:2); and a third peptide comprising SEQ ID NO: 5 (such as a third peptide consisting of SEQ ID NO: 5); Alternatively, such an antibody or antigen-binding fragment thereof may specifically bind to a longer amino acid sequence according to SEQ ID NO:3 instead of binding to a shorter amino acid sequence according to SEQ ID NO:1.

[0038] In a further embodiment, the isolated antibody or antigen-binding fragment thereof comprises: a first peptide comprising SEQ ID NO:1 (e.g., a first peptide consisting of SEQ ID NO:1); a second peptide comprising SEQ ID NO:2 (such as a second peptide consisting of SEQ ID NO:2); and a third peptide comprising SEQ ID NO: 6 (such as a third peptide consisting of SEQ ID NO: 6); Alternatively, such antibodies or antigen-binding fragments thereof may bind to the longer amino acid sequence according to SEQ ID NO:3 instead of binding to the shorter amino acid sequence according to SEQ ID NO:1.

[0039] In one embodiment, the antibody is a polyclonal antibody. As used herein, the term "polyclonal antibody" refers to a population of antibodies that react with a specific antigen, although different antibody molecules (e.g., antibodies that recognize different epitopes on the antigen) may be present within the population. Polyclonal antibodies are typically produced by inoculation into a suitable mammal and purified from the mammal's serum.

[0040] In a preferred embodiment, the antibody is a monoclonal antibody. As used herein, the term "monoclonal antibody" refers to an antibody with monovalent affinity, meaning that each antibody molecule in a sample of monoclonal antibody binds to the same epitope of an antigen. Monoclonal antibodies can be produced by the same immune cells that are clones of unique parent cells, for example, clones of hybridoma cell lines; they can also be constructed by genetic engineering (including phage display selection) from human immunoglobulin libraries.

[0041] A complete antibody comprises two heavy chains and two light chains inter-connected by disulfide bonds. Each heavy chain comprises a heavy chain variable region (HCVR) and first, second, and third constant regions (CH1, CH2, and CH3). In this disclosure, the term V H The terms VH, VH, and HCVR are used synonymously. Each light chain comprises a light chain variable region (LCVR) and a light chain constant region (CL). In this disclosure, the term V L , VL and LCVR are used synonymously.

[0042] The HCVR and LCVR regions can be further subdivided into hypervariable regions called complementarity-determining regions (CDRs), separated by more conserved regions called framework regions (FR or FW). Each HCVR and LCVR consists of three CDRs and four FR / FWs, arranged from N-terminus to C-terminus in the following order: FW1, CDR1, FW2, CDR2, FW3, CDR3, FW4.

[0043] It is well known in the art that the paratope, also known as the antigen-binding site, is a portion of an antibody or its antigen-binding fragment that recognizes and binds to an antigen surface called the epitope. The paratope is a small region of the Fv region of an antibody and includes portions of the heavy and light chains of the antibody. Each arm of the Y-shape of an antibody monomer has a paratope at its tip and contains six CDRs: three light chain CDRs (LCDRs) and three heavy chain CDRs (HCDRs).

[0044] Hereinafter, the antibody or antigen-binding fragment thereof of the present invention is defined by the structural features of its CDRs; in other words, by the amino acid sequences of its HCDRs and / or LCDRs, or the amino acid structures of the regions containing the HCDRs and / or LCDRs. Those skilled in the art will understand that minor changes, such as substitutions of one, two, three, four, or more amino acid residues in the amino acid sequence, may be present without affecting the functional properties (such as the binding ability or binding affinity of the antibody or antigen-binding fragment thereof to a BSSL (e.g., hBSSL)). It should be understood that the first HCDR, second HCDR, third HCDR, first LCDR, second LCDR, and third LCDR may be independently selected from the amino acid sequences listed.

[0045] In one embodiment, the antibody or antigen-binding fragment thereof comprises three complementarity determining regions (CDRs) (HCDRs) of the heavy chain variable region (HCVR) and three CDRs (LCDRs) of the light chain variable region (LCVR). In one embodiment, the first HCDR comprises, preferably consists of, an amino acid sequence according to SEQ ID NO:7; the second HCDR comprises, preferably consists of, an amino acid sequence selected from the group consisting of SEQ ID NOs:8, 12, and 13; and the third HCDR comprises, preferably consists of, an amino acid sequence according to SEQ ID NO:9. In one embodiment, the first LCDR comprises, preferably consists of, an amino acid sequence selected from the group consisting of SEQ ID NOs:10 and 14; and the third LCDR comprises, preferably consists of, an amino acid sequence according to SEQ ID NOs:11, 15, and 16.

[0046] The second LCDR of the antibody or antigen-binding fragment thereof is not thought to be significantly involved in BSSL binding. However, in one embodiment, the antibody or antigen-binding fragment thereof comprises a second LCDR comprising an amino acid sequence selected from the group consisting of ATS and AAS, preferably comprising the same.

[0047] In one embodiment, the first HCDR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO:7; the second HCDR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO:8; the third HCDR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO:9; the first LCDR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO:10; the second LCDR comprises, preferably consists of the amino acid sequence ATS; and the third LCDR comprises, preferably consists of the amino acid sequence according to SEQ ID NO:11.

[0048] In one particular embodiment, the HCVR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO: 23. In another particular embodiment, the LCVR comprises, preferably consists of, an amino acid sequence selected from the group consisting of SEQ ID NOs: 24 and 25. Accordingly, in one embodiment, the antibody or antigen-binding fragment thereof comprises a HCVR comprising, preferably consisting of, the amino acid sequence according to SEQ ID NO: 23 and a LCVR comprising, preferably consisting of, the amino acid sequence according to SEQ ID NO: 24. In another embodiment, the antibody or antigen-binding fragment thereof comprises a HCVR comprising, preferably consisting of, the amino acid sequence according to SEQ ID NO: 23 and a LCVR comprising, preferably consisting of, the amino acid sequence according to SEQ ID NO: 25.

[0049] In one embodiment, the antibody or antigen-binding fragment thereof comprises a heavy chain (HC) comprising, preferably consisting of, an amino acid sequence according to SEQ ID NO: 36, and / or a light chain (LC) comprising, preferably consisting of, an amino acid sequence according to SEQ ID NO: 37.

[0050] In another embodiment, the antibody or antigen-binding fragment thereof comprises an HC comprising, preferably consisting of, an amino acid sequence according to SEQ ID NO: 38, and / or an LC comprising, preferably consisting of, an amino acid sequence according to SEQ ID NO: 39.

[0051] In one embodiment, the first HCDR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO:7; the second HCDR comprises, preferably consists of the amino acid sequence according to SEQ ID NO:12; the third HCDR comprises, preferably consists of the amino acid sequence according to SEQ ID NO:9; the first LCDR comprises, preferably consists of the amino acid sequence according to SEQ ID NO:10; the second LCDR comprises, preferably consists of the amino acid sequence ATS; and the third LCDR comprises, preferably consists of the amino acid sequence according to SEQ ID NO:15.

[0052] In one specific embodiment, the HCVR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO: 17. In another specific embodiment, the LCVR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO: 18. Thus, in one embodiment, the antibody or antigen-binding fragment thereof comprises a HCVR comprising, preferably consisting of, the amino acid sequence according to SEQ ID NO: 17 and a LCVR comprising, preferably consisting of the amino acid sequence according to SEQ ID NO: 18.

[0053] In one embodiment, the antibody or antigen-binding fragment thereof comprises an HC comprising, preferably consisting of, an amino acid sequence according to SEQ ID NO: 30 and / or an LC comprising, preferably consisting of, an amino acid sequence according to SEQ ID NO: 31.

[0054] In one embodiment, the first HCDR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO:7; the second HCDR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO:8; the third HCDR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO:9; the first LCDR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO:14; the second LCDR comprises, preferably consists of the amino acid sequence AAS; and the third LCDR comprises, preferably consists of the amino acid sequence according to SEQ ID NO:11.

[0055] In one specific embodiment, the HCVR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO: 19. In another specific embodiment, the LCVR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO: 20. Thus, in one embodiment, the antibody or antigen-binding fragment thereof comprises an HCVR comprising, preferably consisting of, the amino acid sequence according to SEQ ID NO: 19, and an LCVR comprising, preferably consisting of the amino acid sequence according to SEQ ID NO: 20.

[0056] In one embodiment, the antibody or antigen-binding fragment thereof comprises an HC comprising, preferably consisting of, an amino acid sequence according to SEQ ID NO: 32, and / or an LC comprising, preferably consisting of, an amino acid sequence according to SEQ ID NO: 33.

[0057] In one embodiment, the first HCDR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO:7; the second HCDR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO:13; the third HCDR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO:9; the first LCDR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO:14; the second LCDR comprises, preferably consists of the amino acid sequence ATS; and the third LCDR comprises, preferably consists of the amino acid sequence according to SEQ ID NO:16.

[0058] In one specific embodiment, the HCVR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO: 21. In another specific embodiment, the LCVR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO: 22. Thus, in one embodiment, the antibody or antigen-binding fragment thereof comprises an HCVR comprising, preferably consisting of, the amino acid sequence according to SEQ ID NO: 21, and an LCVR comprising, preferably consisting of the amino acid sequence according to SEQ ID NO: 22.

[0059] In one embodiment, the antibody or antigen-binding fragment thereof comprises an HC comprising, preferably consisting of, an amino acid sequence according to SEQ ID NO: 34, and / or an LC comprising, preferably consisting of, an amino acid sequence according to SEQ ID NO: 35.

[0060] In one embodiment, the first HCDR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO:49; the second HCDR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO:50; the third HCDR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO:51; the first LCDR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO:52; the second LCDR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO:53; and the third LCDR comprises, preferably consists of, the amino acid sequence according to SEQ ID NO:15.

[0061] In one particular embodiment, the antibody or antigen-binding fragment thereof comprises an HCVR consisting of SEQ ID NO: 26 and / or an LCVR consisting of SEQ ID NO: 27. One particular example of an antibody or antigen-binding fragment thereof comprises, preferably consists of, a pair of HCVR and LCVR comprising amino acid sequences according to SEQ ID NOs: 26 and 27.

[0062] In a particular embodiment, the antibody or antigen-binding fragment thereof comprises an HC comprising, preferably consisting of, an amino acid sequence selected from the group consisting of SEQ ID NOs: 28, 40, 42, and 47, and / or an LC comprising, preferably consisting of, an amino acid sequence selected from the group consisting of SEQ ID NOs: 29, 41, 43, and 48. Particular examples of antibodies or antigen-binding fragments thereof include pairs of HC and LC comprising, preferably consisting of, amino acid sequences according to SEQ ID NOs: 28 and 29, 40 and 41, 42 and 43, 44 and 45, or 47 and 48.

[0063] Various modifications and / or additions can be made to the antibodies or antigen-binding fragments thereof as disclosed herein to tailor the antibodies or antigen-binding fragments thereof for specific uses without departing from the scope of the present disclosure. For example, the antibodies or antigen-binding fragments thereof may have an amino acid sequence extended with and / or including additional amino acids at the C-terminus and / or N-terminus (e.g., at the C-terminus and / or N-terminus of the heavy or light chain). Thus, the antibodies or antigen-binding fragments thereof may contain any suitable number of additional amino acid residues, e.g., at least one additional amino acid residue. Each additional amino acid residue may be added individually or collectively to, for example, improve and / or simplify the production, purification, in vivo or in vitro stabilization, coupling, or detection of the antibodies or antigen-binding fragments thereof. Such additional amino acid residues may include one or more amino acid residues added for chemical coupling purposes. One example is the addition of a cysteine ​​residue. The additional amino acid residues may also provide a "tag" (such as a His6 tag, a (HisGlu)3 tag, a "myc" (c-myc) tag or a FLAG tag) for purifying or detecting the antibody or antigen-binding fragment thereof.

[0064] The antibodies or antigen-binding fragments thereof of the present invention may be selected from, but are not limited to, whole antibodies, combinations of CDR sequences, single-chain variable fragments, Fab fragments, F(ab')2 fragments, F(ab')3 fragments, Fab' fragments, Fv fragments, dAb fragments, isolated complementarity-determining regions (CDRs), and nanobodies.

[0065] In one embodiment, the antibody or antigen-binding fragment thereof is selected from the group consisting of a human antibody, a humanized antibody, and a chimeric antibody or antigen-binding fragment thereof.

[0066] In one embodiment, the isolated antibody or antigen-binding fragment thereof has an isotype class selected from the group consisting of IgG, IgA, IgM, IgD, and IgE. In a specific embodiment, the isotype class is IgG. For example, the isolated antibody or antigen-binding fragment thereof may be selected from the group consisting of isotype subclasses IgG1 and IgG4.

[0067] For example, it may be desirable to reduce or eliminate the effector functions of an antibody or antigen-binding fragment thereof to prevent unwanted cytokine secretion. Another example in which a reduction in effector function may be necessary is to prevent an antibody-drug conjugate from interacting with Fc receptors (FcγRs) that result in off-target cytotoxicity.

[0068] Thus, in one embodiment, the antibody or antigen-binding fragment thereof comprises at least one Fc silencing mutation that inhibits interaction with FcγR. For example, an antibody or antigen-binding fragment thereof derived from the IgG1 isotype class may comprise at least one, preferably at least two, and more preferably all three of the Fc silencing mutations L234A, L235A, and P329G.

[0069] Additionally, antibodies of the IgG4 isotype, or antigen-binding fragments thereof, are considered potential candidates for immunotherapy in which reduced effector function is desirable. IgG4 antibodies are known to be dynamic molecules capable of a process known as Fab-arm exchange (FAE), which, without being limited to a particular theory, is thought to generate functionally monovalent bispecific antibodies (bsAbs) with unknown specificity and therefore potentially reduced therapeutic efficacy. This may introduce undesirable pharmacokinetic unpredictability into human immunotherapy.

[0070] Thus, in one embodiment, the isolated antibody or antigen-binding fragment thereof comprises at least one stabilizing mutation to prevent or reduce in vivo Fab arm exchange. For example, it has been shown in the art that a single amino acid mutation (S228P) in the IgG4 core-hinge region is sufficient to prevent in vivo FAE. In a specific embodiment, the isolated antibody or antigen-binding fragment thereof is of the IgG4 isotype subclass, and the at least one stabilizing mutation is S228P.

[0071] Currently preferred antibodies or antigen-binding fragments thereof include: SL048-11 (heavy chain SEQ ID NO:30 and light chain SEQ ID NO:31), S-SL048-46 (heavy chain SEQ ID NO:32 and light chain SEQ ID NO:33), SL048-106 (heavy chain SEQ ID NO:34 and light chain SEQ ID NO:35), SOL-116 (heavy chain SEQ ID NO:36 and light chain SEQ ID NO:37), SL048-118 (heavy chain SEQ ID NO:38 and light chain SEQ ID NO:39), AS20 (heavy chain SEQ ID NO:26 and light chain SEQ ID NO:27), AS20 hIgG1 LALA-PG (heavy chain SEQ ID NO:28 and light chain SEQ ID NO:29), AS20 hIgG4 S228P (heavy chain SEQ ID NO:40 and light chain SEQ ID NO:41), CDR-grafted hIgG4 S228P (heavy chain SEQ ID NO:42 and light chain SEQ ID NO:43), AS20 IgG (heavy chain SEQ ID NO:44 and light chain SEQ ID NO:45) and chimeric AS20 IgG4 (Chi-AS20) (heavy chain SEQ ID NO: 47 and light chain SEQ ID NO: 48), Examples include:

[0072] Suitable anti-BSSL antibodies and antigen-binding fragments thereof that can be used in accordance with the present invention are disclosed in WO2021 / 010888, the teachings of which regarding anti-BSSL antibodies are incorporated herein by reference.

[0073] In one embodiment, the antibody or antigen-binding fragment thereof is an isolated antibody or an isolated antigen-binding fragment thereof.

[0074] The present invention also relates to a pharmaceutical composition comprising an antibody or antigen-binding fragment thereof according to the invention and a pharmaceutically acceptable carrier and / or excipient.

[0075] The term "pharmaceutical composition" refers to a preparation in a form in which the biological activity of the active ingredient contained therein is effective and which does not contain any additional ingredients that are intolerably toxic to the subject to which the preparation is administered.

[0076] The pharmaceutical composition may comprise a single type of antibody or a single type of antigen-binding fragment according to the present invention. Alternatively, the pharmaceutical composition may comprise a mixture of different types of antibodies or different types of antigen-binding fragments according to the present invention. The pharmaceutical composition may comprise a mixture of at least one type of antibody according to the present invention and at least one type of antigen-binding fragment according to the present invention.

[0077] The antibody or antigen-binding fragment thereof, or the pharmaceutical composition may be formulated by means known in the art into forms such as, for example, tablets, capsules, aqueous or oily solutions, suspensions, emulsions, creams, ointments, gels, nasal sprays, suppositories, micronized powders or aerosols for inhalation, and for parenteral use, intravenous, subcutaneous or intramuscular infusions or injections, sterile aqueous or oily solutions or suspensions or sterile emulsions, and the like.

[0078] As used herein, the term "pharmaceutically acceptable excipient" refers to an excipient that is non-toxic to a subject. Specific, non-limiting examples of such excipients include diluents, bulking agents, fillers, stabilizers, buffers, preservatives, adjuvants, anti-adherents, binders, coating agents, colorants, disintegrants, flavorings, glidants, lubricants, adsorbents, and sweeteners.

[0079] As used herein, the term "pharmaceutically acceptable carrier" refers to a carrier that is nontoxic to a subject. Pharmaceutically acceptable carriers include, but are not limited to, vehicles, solvents, dispersion media, and the like. Preferably, the carrier is suitable for oral, intravenous, intramuscular, subcutaneous, or epidermal administration (e.g., by injection or infusion). Examples of suitable aqueous and nonaqueous carriers that may be used in the pharmaceutical composition include water, ethanol, polyols (glycerol, propylene glycol, polyethylene glycol, etc.), and suitable mixtures thereof, vegetable oils (e.g., olive oil), and injectable organic esters (e.g., ethyl oleate). Proper fluidity can be maintained, for example, by the use of coating materials (e.g., lecithin), by maintaining the required particle size in the case of dispersions, and by the use of surfactants. Other examples of aqueous carriers used in accordance with the present invention include saline and buffer solutions (e.g., phosphate-buffered saline (PBS)).

[0080] Prevention of the presence of microorganisms can be ensured by both sterilization and the inclusion of various antibacterial and antifungal agents, for example, parabens, chlorobutanol, or phenol sorbic acid. It may also be desirable to include isotonic agents in the composition, such as sugars and sodium chloride. Furthermore, prolonged absorption of injectable pharmaceutical forms can be achieved by including agents that delay absorption, such as aluminum monostearate and gelatin.

[0081] In one example, the pharmaceutical composition may further comprise at least one additional active agent (such as at least two additional active agents, at least three additional active agents, etc.) Non-limiting examples of additional active agents that may prove useful in such combinations include chemotherapeutic agents.

[0082] A further aspect of the present invention relates to the use of an antibody or antigen-binding fragment thereof that specifically binds to BSSL, wherein the antibody or antigen-binding fragment thereof binds to an epitope present in the N-terminal portion of BSSL (ranging from the N-terminus of BSSL to amino acid residue 300 of BSSL, but excluding the active site of BSSL) for the manufacture of a therapeutic agent for treating a BSSL-expressing cancer in a subject.

[0083] BSSL-expressing cancers, as described herein, refer to cancers containing cancer cells that express BSSL (the gene is designated CEL in humans). BSSL-expressing cancers can be determined by detecting the presence of BSSL protein in the culture medium in which cancer cells are cultured or in a tumor biopsy. The presence of BSSL in the culture medium or biopsy can be detected, for example, using a commercially available BSSL / BSDL ELISA kit or using one of the antibodies of the present invention (e.g., by labeling the antibody of the present invention with a detectable label (e.g., a fluorophore, a chemiluminescent label, an enzyme label, a gold label), or by detecting the antibody of the present invention with a labeled secondary antibody). Alternatively, BSSL-expressing cancers can be determined by detecting CEL (BSSL) mRNA transcripts in cultured cancer cells or a tumor biopsy.

[0084] BSSL-expressing cancers are characterized by cancer cells that express BSSL, as described above. In some such BSSL-expressing cancers, the corresponding non-cancerous cells (i.e., wild-type cells) in that particular tissue or organ do not express BSSL. For example, in healthy subjects, BSSL is expressed in the exocrine pancreas, and in some species (such as humans, primates, dogs, cats, and mice), BSSL is also expressed in the lactating mammary gland. This means that BSSL is generally not expressed in, for example, the colon, lung, prostate, and liver of such healthy subjects. However, BSSL expression has been detected in BSSL-expressing colon cancer, colorectal cancer, lung cancer, prostate cancer, and liver cancer. Thus, in such BSSL-expressing cancers, wild-type cells in the relevant healthy tissue or organ (such as the colon, lung, prostate, or liver) generally do not express BSSL, while cancer cells in BSSL-expressing colon cancer, colorectal cancer, lung cancer, prostate cancer, and liver cancer express BSSL.

[0085] BSSL-expressing pancreatic cancer and breast cancer are characterized by their higher BSSL expression in pancreas and breast, respectively, compared with the BSSL expression in the pancreas and breast of healthy subjects who do not suffer from BSSL-expressing pancreatic cancer or BSSL-expressing breast cancer.Therefore, such BSSL-expressing cancer is characterized by higher BSSL expression and therefore higher BSSL amount compared with the pancreas or breast of healthy subjects.

[0086] For example, BSSL-expressing cancers are characterized by at least 25 CEL (BSSL) mRNA transcripts per million, preferably at least 30, such as at least 35, or such as at least 40 or more (such as at least 45 or at least 50). Correspondingly, low- or non-BSSL-expressing cancers have CEL (BSSL) mRNA transcripts per million of 10 or less, preferably 5 or less (such as 4.5 or less or 4 or less (such as 3.5 or less or 3 or less)). Examples of BSSL-expressing and non-BSSL-expressing cancers are discussed in Example 2; see Table 3.

[0087] In one embodiment, the BSSL expression of BSSL-expressing cancer is higher than that of the corresponding healthy tissue from which the BSSL-expressing cancer originates.For example, the BSSL expression of BSSL-expressing colon cancer is higher than that of healthy cells, i.e., non-cancerous colon epithelial cells.This must be compared to a cancer that lacks BSSL or a cancer that has low BSSL expression, and the BSSL expression is substantially the same as that of the corresponding healthy tissue from which the BSSL-expressing cancer originates.Therefore, colon cancer that does not express BSSL or has only low BSSL expression typically has substantially the same BSSL expression as that of healthy colon epithelial cells, i.e., non-cancerous colon epithelial cells.

[0088] Specific, non-limiting examples of BSSL-expressing cancers include BSSL-expressing colon, lung, colorectal, pancreatic, breast, prostate, and liver cancer.

[0089] This document also provides a method for treating a BSSL-expressing cancer in a subject. The method comprises administering to a subject in need thereof a therapeutically effective amount of an antibody or antigen-binding fragment thereof, or a pharmaceutical composition. The antibody or antigen-binding fragment thereof binds to an epitope present in the N-terminal portion of BSSL, extending from the N-terminus to amino acid residue 300 of BSSL, excluding the active site of BSSL.

[0090] As used herein, the term "treatment" or "treating" includes therapeutic measures that cure, slow, alleviate symptoms of, and / or halt the progression of cancer disease; and prophylactic or preventive treatments (which prevent and / or slow the onset of cancer disease), including treatment of subjects at risk of or suspected of having cancer disease, as well as subjects suffering from or diagnosed with cancer disease, and curative, therapeutic, or disease-modifying treatments. This term does not necessarily imply treating a subject until complete recovery. The terms "treatment" and "treating" further include reducing the risk of developing cancer disease (e.g., in a prophylactic treatment manner). The terms "treatment" and "treating" are also intended to include synergistic or potentiating effects of one or more primary preventative or therapeutic measures. Thus, treatment includes clinical intervention in an attempt to alter the natural course of cancer disease in the subject being treated, and can be performed either for preventative purposes or during the clinical pathological course. Desired effects of treatment include, but are not limited to, preventing the onset or recurrence of cancer disease, alleviating symptoms (improving quality of life), directly or indirectly reducing the pathological consequences of cancer disease, preventing metastasis, reducing primary tumor size, slowing the rate of disease progression, ameliorating or alleviating the condition, and alleviating or improving prognosis. The antibody or antigen-binding fragment thereof according to the present invention may be used to delay the onset of cancer disease or slow the progression of cancer disease. "Reducing" or "inhibiting" refers to the ability to cause an overall reduction of 20%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 85%, 90%, 95% or more. Reducing or inhibiting can refer to the symptoms of the cancer disease being treated. Reducing or inhibiting also includes delaying the onset of cancer disease.

[0091] Treatment with the antibodies or antigen-binding fragments thereof or pharmaceutical compositions disclosed herein is typically passive immunotherapy, where passive immunotherapy refers to administering to a subject in need thereof an antibody or antigen-binding fragment thereof, or a pharmaceutical composition comprising such an antibody or antigen-binding fragment thereof.

[0092] The subject according to the present disclosure may be any human or non-human animal. The term "non-human animal" includes all vertebrates, for example, mammals and non-mammals (non-human primates, sheep, dogs, cats, horses, cows, chickens, amphibians, reptiles, etc.). Mammals include, but are not limited to, domestic animals, for example, cows, sheep, cats, dogs, and horses, primates, for example, humans and non-human primates (such as monkeys), rabbits, and rodents (such as mice and rats). The term "subject" is sometimes used synonymously with the term "patient" herein. The subject may be a human.

[0093] An antibody or antigen-binding fragment thereof, or pharmaceutical composition according to the invention may be administered in standard manner for the condition for which it is desired to treat, for example, orally, topically, parenterally, intravenously, subcutaneously, buccally, nasally, or rectally, or by inhalation. For example, the antibody or antigen-binding fragment thereof, or pharmaceutical composition may be formulated for parenteral administration, such as intravenously or subcutaneously, especially subcutaneously.

[0094] Typically, the antibody or antigen-binding fragment thereof or the pharmaceutical composition is administered systemically. The mode of administration may be, for example, parenteral (intravenous or subcutaneous administration, particularly subcutaneous administration). However, local administration, such as intratumoral administration, can also be used as an alternative to or complement systemic administration.

[0095] The dosing regimen may be tailored to the particular cancer disease and subject being treated, but typically the antibody or antigen-binding fragment thereof or the pharmaceutical composition is administered 1-3 times per week (e.g., 1-2 times per week, e.g., once per week); however, other dosing regimens are also possible.

[0096] The antibody or antigen-binding fragment thereof or the pharmaceutical composition may also be administered in combination therapy (i.e., in combination with other agents). For example, the combination therapy may include an antibody or antigen-binding fragment thereof according to the present invention combined with at least one chemotherapy. It should be understood that the combination therapy includes sequential administration as well as simultaneous administration. As used herein, the term "simultaneous" refers to the administration of two or more therapeutic agents, the administration of which overlaps in time at least in part. Thus, combination administration includes a dosing regimen in which the administration of one or more agents is discontinued followed by the continuation of the administration of one or more other agents. Alternatively, the combination therapy may include an antibody or antigen-binding fragment thereof according to the present invention combined with another anti-cancer treatment (such as radiation therapy or surgery).

[0097] Dosage regimens may be adjusted to provide the optimum desired response (e.g., a therapeutic response). For example, a single bolus may be administered; multiple divided doses may be administered over time; or the dose may be proportionally reduced or increased as indicated by the therapeutic situation. It is particularly convenient to formulate parenteral compositions in unit dosage forms for ease of administration and uniformity of dosage.

[0098] A therapeutically effective amount of an antibody or antigen-binding fragment thereof may vary depending on factors such as the subject's condition, age, sex, and weight, as well as the ability of the antibody or antigen-binding fragment thereof to elicit a desired response in the subject. A therapeutically effective amount is also an amount in which the therapeutically beneficial effects outweigh any toxic or harmful effects of the administered antibody or antigen-binding fragment thereof. When the antibody or antigen-binding fragment thereof is used to prevent a pathological condition (prophylactic purposes), if a prophylactic dose is used on a subject before the subject is affected by the cancer disease or at an early stage of the cancer disease, the prophylactically effective amount is typically, but not always, less than the therapeutically effective amount.

[0099] A pharmaceutically effective amount (i.e., dosage) of an antibody or antigen-binding fragment thereof according to the present invention is typically in the range of about 0.0001 to 100 mg / kg of the subject's body weight, more usually in the range of 0.01 to 5 mg / kg of the subject's body weight, although the exact dosage is preferably adjusted depending, for example, on the cancer disease being treated or prevented, the age and / or sex of the subject, and whether treatment or prevention of the condition is intended.

[0100] Example Example 1: Efficacy evaluation of SOL-116 against primary tumors and metastases in four different indications in ZTX®-ONCOLEADS The purpose of this example was to determine the possible effectiveness of SOL-116 on primary tumor size and metastasis formation. Four different cell lines were used to determine the anti-cancer efficacy of SOL-116 based on the change in primary tumor size, i.e., tumor growth or tumor shrinkage, and the number of tumor cells disseminated into the distal caudal venous plexus (CVP) 3 days after implantation.

[0101] Study Design In this example, four different cell lines representing four different cancer indications were examined. A human IgG4 antibody (human IgG4 S241P standard (Abzena)) was used as a control. The efficacy of SOL-116 on primary tumor size was evaluated immediately after implantation and three days later. Metastasis was evaluated three days after implantation.

[0102] [Table 1]

[0103] Zebrafish tumor xenograft (ZTX) model Transgenic zebrafish Tg(Fli1:EGFP)y1 embryos were cultured in E3 embryo medium containing 0.2 mM 1-phenyl-2-thiourea (PTU) for 48 hours at 28°C. Unfertilized eggs, unhealthy-looking larvae, or larvae with obvious developmental defects were excluded before the start of treatment.

[0104] Approximately 500 Dil-labeled cancer cells were injected subcutaneously into the perivitelline space of 2-day-old larvae, along with 10 mg / L of human IgG4 S241P control antibody or 10 mg / L of SOL-116. Larvae in which tumor cells were injected into the circulation or in which tumors were mistakenly implanted in the yolk rather than the perivitelline space were excluded from the study. Selected tumor-bearing embryos were assigned to experimental groups (20 embryos per group); photographs of the primary tumors were taken immediately after injection. The tumor-bearing embryos were incubated in E3 + PTU medium at 36°C for 72 hours. After incubation, photographs of the primary tumors and CVP were taken. Larvae that died or were otherwise lost during the course of the study were excluded from the final analysis.

[0105] Analysis of tumor growth inhibition and metastasis Images acquired immediately after implantation (day 0) and after 72 hours of incubation (day 3) were analyzed using in-house developed software (BioReperia). Tumor growth regression was calculated by dividing the tumor pixel count on day 3 by the tumor pixel count on day 0 in the same embryo and multiplying by 100.

[0106] statistical analysis Data are presented as mean ± standard error of the mean (SEM); Student's t-test was used to determine p values; differences corresponding to values ​​<0.05 were considered significant. Experimental data were analyzed using GraphPad.

[0107] result All analyzed cell lines successfully engrafted and formed metastases in zebrafish embryos. Figure 1 shows the aggregate results for all analyzed cell lines for their effects on both primary tumors and metastases, normalized to the human IgG4 S241P isotype control (isocontrol). After 3 days of treatment, SOL-116 treatment nonsignificantly reduced the growth of HCT116 primary tumors compared to the human IgG4 S241P isotype control (isocontrol). SOL-116 treatment also significantly reduced the number of distant metastases observed at the CVP site. After 3 days of treatment, SOL-116 had no significant effect on the growth of PC3 primary tumors or the number of distant metastases compared to the human IgG4 S241P isotype control (isocontrol). After 3 days of treatment, SOL-116 had no significant effect on the growth of BT-549 primary tumors compared to the human IgG4 S241P isotype control (isocontrol), but did slightly but nonsignificantly reduce the number of distant metastases. After 3 days of treatment, SOL-116 treatment non-significantly reduced the growth of HPAF-II primary tumors compared with the human IgG4 S241P isotype control (isocontrol), but SOL-116 treatment had no effect on the number of distant metastases.

[0108] Among the four cancer cell lines examined in this example, the HCT-116 colorectal cancer cell line is the highest performing BSSL cancer cell line.

[0109] Example 2: Efficacy evaluation of SOL-116 against primary tumors and metastases in PDX models in ZTX®-ONCOLEADS The purpose of this example was to determine the anti-cancer efficacy of SOL-116 on primary tumor size and metastasis formation in lung and colorectal cancer PDX models. The anti-cancer efficacy of SOL-116 was determined based on the change in primary tumor size, i.e., tumor growth or shrinkage, and the number of tumor cells disseminated into the distal CVP 3 days after implantation.

[0110] Study Design This example consisted of six different PDX models representing two different cancer indications. Three of these models expressed high levels of BSSL mRNA, while the remaining three expressed no or low levels (Table 3). Vehicle (phosphate-buffered saline, PBS) was used as a negative control. The same isotype control and anti-BSSL antibody (SOL-116) as in Example 1 were also used in this example. Primary tumor size was assessed immediately and 3 days after implantation. Metastasis was assessed 3 days after implantation.

[0111] [Table 2]

[0112] [Table 3]

[0113] Zebrafish tumor xenograft (ZTX) model Transgenic zebrafish Tg(Fli1:EGFP)y1 embryos were cultured in E3 embryo medium containing 0.2 mM PTU for 48 hours at 28°C. Unfertilized eggs, unhealthy-looking larvae, or larvae with obvious developmental defects were excluded before treatment began.

[0114] Approximately 700 Dil-labeled cancer cells were injected subcutaneously into the perivitelline space of 2-day-old larvae, along with 10 mg / L of human IgG4 S241P control antibody or 10 mg / L of SOL-116. Larvae in which tumor cells were injected into the circulation or in which tumors were mistakenly implanted in the yolk rather than the perivitelline space were excluded from the study. Selected tumor-bearing embryos were assigned to experimental groups (20 embryos per group); photographs of the primary tumors were taken immediately after injection. The tumor-bearing embryos were incubated in E3 + PTU medium at 36°C for 72 hours. After incubation, photographs of the primary tumors and CVP were taken. Larvae that died or were otherwise lost during the course of the study were excluded from the final analysis.

[0115] Analysis of tumor growth inhibition and metastasis Images acquired immediately after implantation (day 0) and after 72 hours of incubation (day 3) were analyzed using in-house developed software (BioReperia). Tumor growth regression was calculated by dividing the tumor pixel count on day 3 by the tumor pixel count on day 0 in the same embryo and multiplying by 100.

[0116] statistical analysis Data are presented as mean ± standard error of the mean (SEM); Student's t-test was used to determine p values; differences corresponding to values ​​<0.05 were considered significant. Experimental data were analyzed using GraphPad.

[0117] result LXS-1129 Figure 2 shows that after 3 days of treatment, SOL-116 significantly reduced primary tumor growth compared to the negative control and the human IgG4 S241P isotype control. Treatment with SOL-116 resulted in a non-significant reduction in the number of distant metastases observed at the CVP site.

[0118] CXF-1788 Figure 3 shows that after 3 days of treatment, SOL-116 significantly reduced the size of primary tumors compared to the negative control and the human IgG4 S241P isotype control. After 3 days of treatment, SOL-116 had no effect on the number of distant metastases compared to the human IgG4 S241P isotype control.

[0119] CXF-158 Figure 4 shows that SOL-116 significantly affected the growth of CXF-158 primary tumors compared with the negative control and the human IgG4 S241P isotype control. After 3 days of treatment, SOL-116 did not affect the number of distant metastases compared with the negative control.

[0120] LXFS-2156 Figure 5 shows that SOL-116 had no significant effect on the growth of LXFS-2156 primary tumors, but significantly affected the number of distant metastases after 3 days of treatment compared with the human IgG S241P isotype control.

[0121] CXF-2836 Figure 6 shows that SOL-116 had no significant effect on the growth of CXF-2836 primary tumors compared with the negative control (human IgG S241P isotype control). After 3 days of treatment, SOL-116 significantly increased the number of distant metastases compared with the negative control (human IgG4 S241P isotype control).

[0122] However, the significant changes in the number of metastatic cancer cells observed in the CXF-2836PDX model were not considered biologically relevant due to the low metastatic potential exhibited by the model. To assess the anti-metastatic efficacy of a drug in the ZTX® model, an average of more than five disseminated cancer cells must be observed in the CVP.

[0123] CXF-533 Figure 7 shows that after 3 days of treatment, SOL-116 had no significant effect on the growth of CXF-533 primary tumors or the number of distant metastases compared to the negative control group and / or the human IgG4 S241P isotype control.

[0124] conclusion SOL-116 demonstrated antitumor efficacy in the LXFS-1129, CXF-1788, and CXF-158 PDX models, which correlated with their high BSSL expression levels. SOL-116 did not demonstrate any antitumor effect in the LXFS-2156, CXF-533, and CXF-2836 PDX models, which correlated with their low BSSL expression levels.

[0125] Example 3: Efficacy evaluation of SOL-116 and other anti-BSSL antibodies against primary tumors and metastases in PDX models in ZTX®-ONCOLEADS The objective of this example was to evaluate the anti-cancer efficacy of SOL-116 and other anti-BSSL antibodies on primary tumor size and metastasis formation in lung and colorectal cancer PDX models with high or low BSSL expression. Anti-cancer efficacy was determined based on the change in primary tumor size, i.e., tumor growth or shrinkage, and the number of tumor cells disseminated into the distal CVP 3 days after implantation.

[0126] Study Design This example consisted of four different PDX models representing two different cancer indications. Two of these models expressed high levels of BSSL mRNA, while the remaining two expressed no or low levels (Table 4). An irrelevant human IgG4 antibody was used as an isotype control. Vehicle (phosphate-buffered saline, PBS) was used as a negative control. Primary tumor size was assessed immediately and 3 days after implantation. Metastasis was assessed 3 days after implantation.

[0127] [Table 4]

[0128] Zebrafish tumor xenograft (ZTX) model Transgenic zebrafish Tg(Fli1:EGFP)y1 embryos were cultured in E3 embryo medium containing 0.2 mM PTU for 48 hours at 28°C. Unfertilized eggs, unhealthy-looking larvae, or larvae with obvious developmental defects were excluded before treatment began.

[0129] PDX tumor tissue was dissociated and single-cell suspensions were labeled with Dil Red fluorescent dye. Approximately 700 Dil-labeled cancer cells were injected subcutaneously into the perivitelline space of 2-day-old larvae, along with 10 mg / L of a human IgG4 B1-8 isotype antibody, antibody SOL-116, antibody Chia-AS20, or antibody SL048-46. Larvae with tumor cells injected into the circulation or tumors mistakenly implanted in the yolk rather than the perivitelline space were excluded from the study. Selected tumor-bearing embryos were assigned to experimental groups (20 embryos per group); photographs of the primary tumors were taken immediately after injection. The tumor-bearing embryos were incubated in E3 + PTU medium at 36°C for 72 hours. After incubation, photographs of the primary tumor and CVP were taken. Larvae that died or were otherwise lost during the study were excluded from the final analysis.

[0130] Analysis of tumor growth inhibition and metastasis Images acquired immediately after implantation (day 0) and after 72 hours of incubation (day 3) were analyzed using in-house developed software (BioReperia). Tumor growth regression was calculated by dividing the number of tumor pixels on day 3 by the number of tumor pixels on day 0 in the same embryo and multiplying by 100. The number of cancer cells seeded at the CVP site was manually counted.

[0131] statistical analysis Data are presented as mean ± standard error; Student's t-test was used to determine p values; differences corresponding to values ​​<0.05 were considered significant. Experimental data were analyzed using GraphPad.

[0132] result LXFS-1129 Figure 8 shows that after 3 days of treatment, treatment with antibody SL048-46 significantly reduced primary tumor size compared to the negative control and the isotype IgG4 B1-8 control groups, while treatment with antibody SOL-116 and treatment with antibody Chi-AS20 significantly reduced primary tumor size compared to the isotype IgG4 B1-8 control groups.

[0133] Figure 8 shows that treatment with antibody SOL-116 was borderline significant (p=0.071) in reducing the size of primary tumors compared to the negative control group. Furthermore, when this data was pooled with that of Example 2, this effect reached mathematical significance (Figure 9).

[0134] CXF-158 Figure 10 shows that after 3 days of treatment, treatment with SOL-116 significantly reduced the size of primary tumors compared to the negative control group. Compared to the isotype IgG4 B1-8 control group, treatment with SOL-116 had no effect on primary tumor size (Figure 10). However, when tumor data were aggregated, SOL-116 significantly reduced the size of primary tumors compared to the isotype IgG4 B1-8 control group (Figure 11).

[0135] LXFS-2156 Figure 12 shows that treatment with antibodies SOL-116, Chi-AS20, or SL048-46 had no significant effect on primary tumor size compared to the negative control or isotype IgG4 B1-8 control groups after 3 days of treatment, and this effect remained unchanged when the negative control and SOL-116 data were combined (Figure 13).

[0136] Figure 12 also shows that after 3 days of treatment, treatment with antibody SL048-46 significantly reduced the number of tumor cells seeded into the CVP compared to the negative control group; on the other hand, treatment with antibodies SOL-116 or Chi-AS20 had no effect on tumor cell seeding (Figure 12).

[0137] CXF-533 Figure 14 shows that after 3 days of treatment, treatment with antibodies SOL-116, Chi-AS20, or SL048-46 had no significant effect on primary tumor size compared to the negative control or isotype IgG4 B1-8 control groups; this effect remained unchanged when the negative control and SOL-116 data were combined (Figure 14). Figure 15 also shows that after 3 days of treatment, treatment with antibodies SOL-116, Chi-AS20, SL048-46, or CDR-grafted antibodies had no effect on the number of tumor cells disseminated at the CVP site.

[0138] conclusion The inventors conclude that the antitumor efficacy and specificity of SOL-116 in Example 2 have been confirmed. Antibody SOL-116 exhibited antitumor efficacy against the lung cancer and colorectal cancer PDX models LXFS-1129 and CXF-158, which correlates with their high BSSL expression status. On the other hand, antibodies Chi-AS20 and SL048-46 only exhibited antitumor efficacy against the lung cancer LXFS-1129 model, but not against the colorectal cancer CXF-158 model; this indicates that the antitumor effects of these antibodies are limited. None of the tested antibodies exhibited antitumor efficacy against the LXFS-2156 and CXF-533 PDX models; this correlates with their low BSSL expression.

[0139] [Table 5] TIFF2025534687000007.tif235159TIFF2025534687000008.tif229159TIFF2025534687 000009.tif230159TIFF2025534687000010.tif235159TIFF2025534687000011.tif40159

[0140] It should be understood that the above-described embodiments are only a few specific examples of the present invention. Those skilled in the art will appreciate that various modifications, combinations, and variations can be made to the embodiments without departing from the scope of the present invention. In particular, different partial solutions of different embodiments can be combined into different configurations, where technically possible.

Claims

1. 1. An antibody or antigen-binding fragment thereof for use in treating bile salt-stimulated lipase (BSSL)-expressing cancer in a subject; wherein the antibody or antigen-binding fragment thereof specifically binds to BSSL; wherein the antibody or antigen-binding fragment thereof binds to an epitope present in the N-terminal portion of BSSL (ranging from the N-terminus of BSSL to amino acid residue 300 of BSSL, but excluding the active site of BSSL). An antibody or antigen-binding fragment thereof.

2. 2. An antibody or antigen-binding fragment thereof for use according to claim 1, wherein said antibody or antigen-binding fragment thereof does not affect the lipase enzymatic activity of BBSL.

3. 3. An antibody or antigen-binding fragment thereof for use according to claim 1 or 2, wherein the antibody or antigen-binding fragment thereof is: a first surface comprising an amino acid sequence according to SEQ ID NO: 1; and a second surface comprising an amino acid sequence according to SEQ ID NO:2; An antibody or antigen-binding fragment thereof that binds to an epitope of BSSL comprising:

4. 4. An antibody or antigen-binding fragment thereof for use according to claim 3, wherein said first surface comprises an amino acid sequence according to SEQ ID NO:

3.

5. 5. An antibody or antigen-binding fragment thereof for use according to claim 3 or 4, wherein the antibody or antigen-binding fragment thereof is: Amino acid sequence according to SEQ ID NO: 5; Amino acid sequence according to SEQ ID NO: 4; and the amino acid sequence according to SEQ ID NO: 6, An antibody or antigen-binding fragment thereof, which further specifically binds to a surface selected from the group consisting of:

6. An antibody or antigen-binding fragment thereof for use according to any one of claims 1 to 5, wherein the antibody or antigen-binding fragment thereof is: three complementarity-determining regions (CDRs) of the heavy chain variable region (HCVR); and three CDRs (LCDRs) of the light chain variable region (LCVR); Including; where The first HCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 7; the second HCDR comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 8, 12 and 13, and preferably consists of the same; the third HCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO:9; the first LCDR comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 10 and 14, and preferably consists of the same; and The third LCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 11, 15, and 16; An antibody or antigen-binding fragment thereof.

7. 7. An antibody or antigen-binding fragment thereof for use according to claim 6, wherein said antibody or antigen-binding fragment thereof comprises a second LCDR, preferably consisting of same; wherein the second LCDR comprises an amino acid sequence selected from the group consisting of ATS and AAS. An antibody or antigen-binding fragment thereof.

8. An antibody or antigen-binding fragment thereof for use according to claim 6 or 7, comprising: where the first HCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 7; the second HCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO:8; the third HCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO:9; the first LCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 10; the second LCDR comprises, and preferably consists of, the amino acid sequence ATS; and the third LCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 11; An antibody or antigen-binding fragment thereof.

9. 9. An antibody or antigen-binding fragment thereof for use according to claim 8, comprising: where the HCVR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 23; and / or The LCVR comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 24 and 25, and preferably consists of the same; An antibody or antigen-binding fragment thereof.

10. 10. An antibody or antigen-binding fragment thereof for use according to claim 9, comprising: where The heavy chain (HC) comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 36; and / or The light chain (LC) comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 37; An antibody or antigen-binding fragment thereof.

11. 10. An antibody or antigen-binding fragment thereof for use according to claim 9, comprising: where The heavy chain (HC) comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 38; and / or The light chain (LC) comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 39; An antibody or antigen-binding fragment thereof.

12. An antibody or antigen-binding fragment thereof for use according to claim 6 or 7, comprising: where the first HCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 7; the second HCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 12; the third HCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO:9; the first LCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 10; the second LCDR comprises, and preferably consists of, the amino acid sequence ATS; and the third LCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 15; An antibody or antigen-binding fragment thereof.

13. An antibody or antigen-binding fragment thereof for use according to claim 12, comprising: where the HCVR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 17; and / or The LCVR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 18; An antibody or antigen-binding fragment thereof.

14. 14. An antibody or antigen-binding fragment thereof for use according to claim 13, comprising: where The heavy chain (HC) comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 30; and / or The light chain (LC) comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 31; An antibody or antigen-binding fragment thereof.

15. An antibody or antigen-binding fragment thereof for use according to claim 6 or 7, comprising: where the first HCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 7; the second HCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO:8; the third HCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO:9; the first LCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 14; the second LCDR comprises, and preferably consists of, the amino acid sequence AA; and the third LCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 11; An antibody or antigen-binding fragment thereof.

16. 16. An antibody or antigen-binding fragment thereof for use according to claim 15, comprising: where the HCVR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 19; and / or The LCVR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 20; An antibody or antigen-binding fragment thereof.

17. 17. An antibody or antigen-binding fragment thereof for use according to claim 16, comprising: where The heavy chain (HC) comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 32; and / or The light chain (LC) comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 33; An antibody or antigen-binding fragment thereof.

18. An antibody or antigen-binding fragment thereof for use according to claim 6 or 7, comprising: where the first HCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 7; the second HCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 13; the third HCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO:9; the first LCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 14; the second LCDR comprises, and preferably consists of, the amino acid sequence ATS; and the third LCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 16; An antibody or antigen-binding fragment thereof.

19. 19. An antibody or antigen-binding fragment thereof for use according to claim 18, comprising: where The HCVR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 21; and / or The LCVR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 22; An antibody or antigen-binding fragment thereof.

20. 20. An antibody or antigen-binding fragment thereof for use according to claim 19, comprising: where The heavy chain (HC) comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 34; and / or The light chain (LC) comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 35; An antibody or antigen-binding fragment thereof.

21. An antibody or antigen-binding fragment thereof for use according to any one of claims 1 to 5, comprising: where the first HCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 49; the second HCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 50; the third HCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 51; the first LCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 52; the second LCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 53; and the third LCDR comprises, and preferably consists of, an amino acid sequence according to SEQ ID NO: 15; An antibody or antigen-binding fragment thereof.

22. 22. An antibody or antigen-binding fragment thereof for use according to claim 21, comprising: where the heavy chain (HC) comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 28, 40, 42, and 47, and preferably consists of the same; and / or The light chain (LC) comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 29, 41, 43, and 48, and preferably consists of the same; An antibody or antigen-binding fragment thereof.

23. 23. The antibody or antigen-binding fragment thereof for use according to any one of claims 1 to 22, wherein the BSSL-expressing cancer is selected from the group consisting of colon cancer, lung cancer, colorectal cancer, pancreatic cancer, breast cancer, prostate cancer and liver cancer.

24. 24. The antibody or antigen-binding fragment thereof for use according to any one of claims 1 to 23, wherein the BSSL-expressing cancer is characterized by a number of carboxyl ester lipase (CEL) messenger ribonucleic acid (mRNA) transcripts per million of at least 25, preferably at least 30, such as at least 35, or at least 40 or more, such as at least 45 or at least 50. An antibody or antigen-binding fragment thereof.

25. 25. An antibody or antigen-binding fragment thereof for use according to any one of claims 1 to 24, characterized in that the BSSL expression in the BSSL-expressing cancer is higher than the BSSL expression in the corresponding healthy tissue from which the cancer originates. An antibody or antigen-binding fragment thereof.

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