Ligand drug conjugates and their applications

Abstract

Ligand drug conjugates and applications of said ligand drug conjugates.

Description

[Technical field]

[0001] The present application relates to the field of biomedical chemistry. More specifically, the present application relates to ligand-drug couplings and applications of said ligand-drug conjugates. [Background technology]

[0002] Antibody-drug conjugates (ADCs) are made by coupling an antibody, which can target cell surface molecules, with a biologically active molecule through chemical linkage, and by using the targeting action of the antibody to orient and transport the biologically active molecule to the target cell, thereby improving the therapeutic effect and reducing the toxicity of cytotoxins to normal tissues and cells. However, due to the complexity and large molecular weight of the antibody in ADCs, their research and development has faced many difficulties, including a lack of suitable targets, production difficulties, and poor drug stability. Currently, ADCs are mainly used in the field of tumor treatment. In some cases, the affinity of the targeting antibody to the cancer cell surface antigen is 10 -9 ~10 -12 (Kd, mol / L), ADCs have high specificity for target cells, and also for normal cells that have the same target receptor as the target cells. At the same time, ADCs have a long metabolic time in the body (1-3 weeks), during which they constantly kill normal cells, greatly increasing the toxic side effects of ADCs. Therefore, a more ideal indication for ADCs should be diseases characterized by a very large difference in the amount of cell surface antigens between tumors and normal cells. However, there are very few diseases currently known that meet this strict requirement. In addition, in the production of antibody-drug conjugates, it is often not possible to determine the ratio of drug to antibody, which affects the evaluation of the efficacy and toxicity of ADCs.

[0003] The drug conjugate compound for targeting biologically active molecules to target cells may be a ligand-drug conjugate (LDC), where the ligand may be a peptide or a small molecule. Compared with antibody-drug conjugates for antibody-based targeting, the ligand-drug conjugate is oriented as a peptide or a small molecule, and the ligand and drug having targeting action in the ligand-drug conjugate generally have precise values. However, the application of LDC also faces many challenges in terms of bioavailability, stability, therapeutic effect, toxicity, etc. For example, many ligands cannot enter cells due to their large molecular weight, lipophilicity, or other attributes, limiting their therapeutic application. In addition, it is also very important to release biologically active molecules in a timely and precise manner through the linker; for example, premature release of the drug may not achieve the ideal therapeutic effect and may even cause animal poisoning death. On the other hand, when the ligand is coupled with a conventional chemotherapy drug (e.g., polysorbicin, paclitaxel, etc.), the therapeutic effect is generally low, but when it is coupled with a highly efficient drug molecule (e.g., MMAE, DM1, etc.), the toxicity is high and may cause the animal to die of poisoning before reaching the therapeutically effective dose for tumor treatment. Therefore, the selection of the ligand, linker, and biologically active molecule is a crucial element of LDC design.

[0004] The design of targeting ligands needs to consider binding affinity, target selectivity and size of the compound. Good ligand binding affinity and selectivity can reasonably reduce the drug dose required to achieve efficient treatment and reduce toxic side effects. The size of the ligand also affects the delivery of bioactive molecules to target cells (e.g., from toxic agents to solid tumors) by different mechanisms, including permeability. Low molecular weight therapeutic drugs are easier to release and diffuse, and are also more easily metabolized. Therefore, even if the drug is off-target, it can generally be excreted from the body in a timely manner, thereby reducing the harmful effects in normal cells. The range of ligand selection is wider, but it is not as direct as antibodies, and it generally requires a lot of effort to select a suitable ligand. Linkers, as links between targeting ligands and bioactive molecules, need to be carefully designed to optimize functions such as drug release, pharmacokinetics and pharmacological properties to retain the affinity and selectivity of the targeting ligand, and the efficacy of the bioactive molecule. For the selection of cytotoxic molecules, release rate, cellular activity, stability within cells, etc. need to be considered.

[0005] Therefore, there is an urgent need to improve LDCs in the field. In particular, by designing a good linker, LDCs can achieve the desired effects, and the ligand moiety and the bioactive molecule can retain the desired properties and functions, thereby enhancing the efficacy or reducing the side effects of the drug. Summary of the Invention

[0006] One aspect of the present application provides a conjugate compound having the structure: Multi-ligand moiety - (linker-payload) q , Where: the multi-ligand moiety comprises at least two ligands that target different cell surface molecules; The linker-payload portion has the structure: [ka] Where: R is [ka] is selected from R1 is independently selected from a bond and -CH2CH2C(O)-NH-; R2 is independently hydrogen or [ka] is selected from R3 is independently hydrogen or [ka] is selected from R4 is independently hydrogen or [ka] is selected from R5 each independently represents a bond, -(CH2CH2O)3-CH2CH2-, -CH2C(O)-NH-CH2-, -CH2C(O)-, -CH2C(O)-NH-CH2C(O)-, and [ka] is selected from R6 independently represents a bond; [ka] is selected from Each X is independently selected from a bond, C, and O; Each m is independently 0 or 1; Each n is independently 0 or 1; p is 0 or 1; q is an integer from 1 to 4, D is the payload.

[0007] Another aspect of the present application provides a conjugate compound having the structure: Multi-ligand moiety - (linker-payload) q , Where: the multi-ligand moiety comprises at least two ligands that target different cell surface molecules; The linker-payload portion has the structure: [ka] Where: R is [ka] is selected from R1 is independently selected from a bond and -CH2CH2C(O)-NH-; R2 is independently hydrogen or [ka] is selected from R3 is independently hydrogen or [ka] is selected from R4 is independently hydrogen or [ka] is selected from R5 each independently represents a bond, -(CH2CH2O)3-CH2CH2-, -CH2C(O)-NH-CH2-, -CH2C(O)-, -CH2C(O)-NH-CH2C(O)-, and [ka] is selected from Each m is independently 0 or 1; Each n is independently 0 or 1; p is 0 or 1; q is an integer from 1 to 4, D is the payload.

[0008] Another aspect of the present application provides a conjugate compound having the structure: Multi-ligand moiety - (linker-payload) q , Where: the multi-ligand moiety comprises at least two ligands that target different cell surface molecules; The linker-payload portion has the structure: [ka] Where: R1 is independently selected from a bond and -CH2CH2C(O)-NH-; R2 is independently hydrogen or [ka] is selected from R5 each independently represents a bond, -(CH2CH2O)3-CH2CH2-, -CH2C(O)-NH-CH2-, -CH2C(O)-, -CH2C(O)-NH-CH2C(O)-, and [ka] is selected from R6 independently represents a bond; [ka] is selected from Each X is independently selected from a bond, C, and O; Each n is independently 0 or 1; q is an integer from 1 to 4, D is the payload.

[0009] Another aspect of the present application provides a conjugate compound having the structure: Multi-ligand moiety - (linker-payload) q , Where: the multi-ligand moiety comprises at least two ligands that target different cell surface molecules; The linker-payload portion has the structure: [ka] Where: R1 is independently selected from a bond and -CH2CH2C(O)-NH-; R3 is independently selected from hydrogen and -R1-R-NH-R5-D; R4 is hydrogen or [ka] and R is [ka] is selected from R5 is independently selected from a bond, -(CH2CH2O)3-CH2CH2-, -CH2C(O)-NH-CH2-, -CH2C(O)-NH-CH2C(O)-, and -CH2C(O)-; R6 independently represents a bond; [ka] is selected from Each X is independently selected from a bond, C, and O; Each m is independently 0 or 1; q is an integer from 1 to 4, D is the payload.

[0010] Another aspect of the present application provides a conjugate compound having the structure: Multi-ligand moiety - (linker-payload) q , Where: the multi-ligand moiety comprises at least two ligands that target different cell surface molecules; The linker-payload portion has the structure: [ka] Where: R1 is independently selected from a bond and -CH2CH2C(O)-NH-; R3 is independently selected from hydrogen and -R1-R-NH-R5-D; R4 is hydrogen or [ka] and R is [ka] and R5 each independently represents a bond, -(CH2CH2O)3-CH2CH2-, -CH2C(O)-NH-CH2-, -CH2C(O)-NH-CH2C(O)-, -CH2C(O)-, and [ka] is selected from R6 independently represents a bond; [ka] is selected from Each X is independently selected from a bond, C, and O; Each m is independently 0 or 1; q is an integer from 1 to 4, D is the payload.

[0011] In some embodiments, R is [ka] It is.

[0012] In some embodiments, R1 is -CH2CH2C(O)-NH-.

[0013] In some embodiments, R5 is -(CH2CH2O)3-CH2CH2-. In other embodiments, R5 is -CH2C(O)-NH-CH2C(O)-. In other embodiments, R5 is -CH2C(O)-. In some embodiments, R5 is [ka] In some other embodiments, R5 is -CH2C(O)-NH-CH2-. In some other embodiments, R5 is not -CH2C(O)-NH-CH2.

[0014] In some embodiments, each m is independently 0 or 1, and n is 0. In some embodiments, each m is independently 0 or 1, and n is 0. In some embodiments, m is 0, and n is independently 0 or 1. In some embodiments, m is 0, and n is 0. In some other embodiments, m is 0, n is 0, and R5 is not -CH2C(O)-NH-CH2-.

[0015] In some embodiments, R6 is [ka] In some embodiments, R6 is [ka] and X is a bond. In some embodiments, R6 is [ka] and X is O. In some embodiments, R6 is [ka] In some embodiments, R6 is [ka] and X is a bond. In some further embodiments, R6 is [ka] and X is O. In some embodiments, R6 is [ka] In some embodiments, R6 is [ka] and X is a bond. In some further embodiments, R6 is [ka] and X is O.

[0016] In some embodiments, p is 0.

[0017] In some embodiments, the linker has a structure selected from the following group: [Table 1] JPEG2024523524000039.jpg214157JPEG2024523524000040.jpg213156JPEG2024523524000041.jpg192157

[0018] In some embodiments, the payload is selected from the following group: a small molecule compound, a nucleotide, and a peptide, preferably, the payload is a small molecule compound.

[0019] In some embodiments, the small molecule compound is selected from the following group: camptothecin and any derivatives thereof, maytansine and any derivatives thereof, radioactive metal complex compounds, cyclooxygenase-2 inhibitors and any derivatives thereof, paclitaxel and any derivatives thereof, epothilone and any derivatives thereof, bleomycin and any derivatives thereof, dactinomycin and any derivatives thereof, plicamycin and any derivatives thereof, and mitomycin C and any derivatives thereof. In some preferred embodiments, the small molecule compound is camptothecin and any derivatives thereof. In some preferred embodiments, the camptothecin is exatecan.

[0020] In some specific embodiments, each D is independently [ka] is selected from.

[0021] In some embodiments, the cell surface molecule is selected from TRPV6, FOLR1, PSMA, and SSTR2.

[0022] In some embodiments, the cell surface molecules are TRPV6 and FOLR1, PSMA and FOLR1, or SSTR2 and FOLR1, respectively. In some preferred embodiments, the cell surface molecules are TRPV6 and FOLR1, respectively. In some embodiments, the FOLR1 targeting ligand is selected from folic acid or an analog thereof. In some preferred embodiments, the folic acid analog is selected from 5-methyltetrahydrofolic acid, 5-formyltetrahydrofolic acid, methotrexate, and 5,10-methylenetetrahydrofolic acid. In some embodiments, the SSTR2 targeting ligand is selected from octreotide and any analog thereof.

[0023] In some embodiments, the ligand moiety comprises three or more ligands that target cell surface molecules, hi some preferred embodiments, the cell surface molecules are selected from TRPV6, FOLR1, PSMA, and SSTR2.

[0024] In some embodiments, ligands targeting different cell surface molecules are linked directly to each other or linked to each other via a spacer region. In some embodiments, the spacer region is comprised of amino acids. In some preferred embodiments, the spacer region is comprised of natural or unnatural amino acids. In some further preferred embodiments, the spacer region is glycine. In some embodiments, the spacer region can be cleaved or reductively cleaved by a protease in a particular physiological environment.

[0025] In some embodiments, the ligand moiety has the structure: [Table 2] JPEG2024523524000044.jpg221158JPEG2024523524000045.jpg210158JPEG2024523524000046.jpg67158

[0026] In some embodiments, q is 1. In some embodiments, q is 2. In some embodiments, q is 3. In some embodiments, q is 4.

[0027] One aspect of the present application provides a conjugate compound selected from the following, or a pharma- ceutically acceptable salt thereof: [Table 3] JPEG2024523524000048.jpg216157JPEG2024523524000049.jpg222157JPEG2024523524000050.jpg227157JPEG2024523524000051.jpg223157JPEG2024523524000052.jpg226157JPEG2024523524000053.jpg224157JPEG2024523524000054.jpg222157JPEG2024523524000055.jpg228157JPEG2024523524000056.jpg223157JPEG2024523524000057.jpg223157JPEG2024523524000058.jpg228157JPEG2024523524000059.jpg226157JPEG2024523524000060.jpg222157JPEG2024523524000061.jpg224157JPEG2024523524000062.jpg215157JPEG2024523524000063.jpg222157JPEG2024523524000064.jpg222157JPEG2024523524000065.jpg228157JPEG2024523524000066.jpg231157JPEG2024523524000067.jpg224157JPEG2024523524000068.jpg221157JPEG2024523524000069.jpg224157JPEG2024523524000070.jpg219157JPEG2024523524000071.jpg224157JPEG2024523524000072.jpg223157JPEG2024523524000073.jpg220157JPEG2024523524000074.jpg221157JPEG2024523524000075.jpg224157JPEG2024523524000076.jpg226157JPEG2024523524000077.jpg229157JPEG2024523524000078.jpg226157JPEG2024523524000079.jpg227157JPEG2024523524000080.jpg225157

[0028] Another aspect of the present application provides a pharmaceutical composition, comprising a conjugate compound described herein or a pharma- ceutical acceptable salt thereof, and a pharma- ceutical acceptable vector. In some embodiments, the pharmaceutical composition described herein is for intravenous, subcutaneous, oral, intramuscular, or intraventricular administration.

[0029] Yet another aspect of the present application provides a method for delivering a payload to a subject in need thereof, the method comprising administering to the subject a therapeutically effective amount of a conjugate compound described herein or a pharma- ceutical acceptable salt thereof, or a pharmaceutical composition described herein.

[0030] Another aspect of the present application provides a method for treating a disease in a subject, the method comprising administering to the subject a therapeutically effective amount of a conjugate compound described herein or a pharma- ceutically acceptable salt thereof, or a pharmaceutical composition described herein. In some embodiments, the method further comprises administering one or more therapeutic agents in combination with the conjugate compound or a pharma- ceutically acceptable salt thereof, or the pharmaceutical composition.

[0031] Another aspect of the present application provides the use of a conjugate compound described herein or a pharma- ceutically acceptable salt thereof, or a pharmaceutical composition described herein, in the manufacture of a medicament for treating a disease in a subject.

[0032] In some embodiments, the disease described in the present application is selected from the following group: cancer, immune disease, metabolic disease, and neurological disease. In some embodiments, the cancer is selected from pancreatic cancer, biliary tract cancer, liver cancer, breast cancer, thyroid cancer, colon cancer, esophageal cancer, lung cancer, kidney cancer, leukemia, ovarian cancer, gastric cancer, uterine cancer, endometrial cancer, colon cancer, testicular cancer, skin cancer, prostate cancer, lymphoma, and multiple myeloma. In some embodiments, the immune disease is an autoimmune disease, preferably, the autoimmune disease is selected from connective tissue disease, systemic sclerosis, rheumatoid arthritis, and systemic lupus erythematosus. The metabolic disease is selected from diabetes, gout, obesity, hypoglycemia, hyperglycemia, and dyslipidemia. In some embodiments, the neurological disease is selected from Alzheimer's disease, Parkinson's disease, Huntington's disease, head injury, multiple sclerosis, dizziness, coma, and epilepsy.

[0033] In some embodiments, the methods of the present application further comprise administering one or more therapeutic agents in combination with said conjugate compound or a pharma- ceutically acceptable salt thereof, or said pharmaceutical composition.

[0034] In some embodiments, the administration frequency of the conjugate compound or its pharma- ceutically acceptable salt or its pharmaceutical composition described herein is once a week, twice a week, three times a week, once every three days, once every two days, once a day, twice a day, or three times a day. In some embodiments, the administration frequency of the conjugate compound or its pharma- ceutically acceptable salt or its pharmaceutical composition described herein is once a week. In some embodiments, the administration frequency of the conjugate compound or its pharma- ceutically acceptable salt or its pharmaceutical composition described herein is three times a day.

[0035] In some embodiments, the conjugate compound or its pharma- ceutically acceptable salt or pharmaceutical composition thereof described herein is administered at a dose range of 1-150 mg / kg of the conjugate compound. In some embodiments, the conjugate compound or its pharma- ceutically acceptable salt or pharmaceutical composition thereof is administered at a dose of 1 mg / kg, 3 mg / kg, 10 mg / kg, 25 mg / kg, 50 mg / kg, 75 mg / kg, 100 mg / kg or 150 mg / kg of the conjugate compound. In some embodiments, the conjugate compound or its pharma- ceutically acceptable salt or pharmaceutical composition thereof described herein is administered at a dose of 50 mg / kg of the conjugate compound. In some embodiments, the conjugate compound or its pharma- ceutically acceptable salt or pharmaceutical composition thereof described herein is administered at a dose of 25 mg / kg of the conjugate compound. [Brief description of the drawings]

[0036] [Figure 1] FIG. 1A shows the change in mouse body weight over time in the test, and FIG. 1B shows the time-dependent change in tumor volume in each group in the MIAPaCa-2 transplanted tumor model. FIG. 1A-FIG. 1B show that the compound of the present application has good antitumor effects in the MIAPaCa-2 transplanted tumor model. [Diagram 2] FIG. 2A shows the change in mouse body weight over time in the test, and FIG. 2B shows the change in mouse initial body weight over time in the test. [Diagram 3] FIG. 3A shows the change in rat body weight over the administration time in the test, and FIG. 3B shows the change in food intake of the test animals in each group during the administration period. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] The following description is merely for illustrating various embodiments of the present application. Therefore, the specific embodiments herein should not be interpreted as limitations on the scope of the application. Those skilled in the art can easily obtain multiple equivalent forms and modifications based on the spirit of the present invention and the description in this specification, and these equivalent embodiments should be understood to be included in the scope of the present invention. All documents, including publications, patents, and patent applications, cited in this application are incorporated by reference in their entirety into this application.

[0038] As used herein, the singular forms "a," "one," "an," and "the" or "said" include plural inclusions unless the context clearly indicates otherwise.

[0039] As used herein, terms such as "comprise," "include," "contain," "containing," and "having" are inclusive or open-ended and do not exclude additional, unrecited elements or method steps. The term "consisting of" is closed-ended.

[0040] One aspect of the present application discloses a conjugate compound having the following structure, or a pharma- ceutically acceptable salt thereof: Multi-ligand moiety - (linker-payload) q , Where: the multi-ligand moiety comprises at least two ligands that target different cell surface molecules; The linker-payload portion has the structure: [ka] Where: R is [ka] is selected from R1 is independently selected from a bond and -CH2CH2C(O)-NH-; R2 is independently hydrogen or [ka] is selected from R3 is independently hydrogen or [ka] is selected from R4 is independently hydrogen or [ka] is selected from R5 each independently represents a bond, -(CH2CH2O)3-CH2CH2-, -CH2C(O)-NH-CH2-, -CH2C(O)-, -CH2C(O)-NH-CH2C(O)-, and [ka] is selected from R6 independently represents a bond; [ka] is selected from Each X is independently selected from a bond, C, and O; Each m is independently 0 or 1; Each n is independently 0 or 1; p is 0 or 1; q is an integer from 1 to 4, D is the payload.

[0041] Another aspect of the present application discloses a conjugate compound having the following structure, or a pharma- ceutically acceptable salt thereof: Multi-ligand moiety - (linker-payload) q , Where: the multi-ligand moiety comprises at least two ligands that target different cell surface molecules; The linker-payload portion has the structure: [ka] Where: R is [ka] is selected from R1 is independently selected from a bond and -CH2CH2C(O)-NH-; R2 is independently hydrogen or [ka] is selected from R3 is independently hydrogen or [ka] is selected from R4 is independently hydrogen or [ka] is selected from R5 each independently represents a bond, -(CH2CH2O)3-CH2CH2-, -CH2C(O)-NH-CH2-, -CH2C(O)-, -CH2C(O)-NH-CH2C(O)-, and [ka] is selected from Each m is independently 0 or 1; Each n is independently 0 or 1; p is 0 or 1; q is an integer from 1 to 4, D is the payload.

[0042] Another aspect of the present application discloses a conjugate compound having the following structure, or a pharma- ceutically acceptable salt thereof: Multi-ligand moiety - (linker-payload) q , Where: the multi-ligand moiety comprises at least two ligands that target different cell surface molecules; The linker-payload portion has the structure: [ka] Where: R1 is independently selected from a bond and -CH2CH2C(O)-NH-; R2 is independently hydrogen or [ka] is selected from R5 each independently represents a bond, -(CH2CH2O)3-CH2CH2-, -CH2C(O)-NH-CH2-, -CH2C(O)-, -CH2C(O)-NH-CH2C(O)-, and [ka] is selected from R6 independently represents a bond; [ka] is selected from Each X is independently selected from a bond, C, and O; Each n is independently 0 or 1; q is an integer from 1 to 4, D is the payload.

[0043] Another aspect of the present application discloses a conjugate compound having the following structure, or a pharma- ceutically acceptable salt thereof: Multi-ligand moiety - (linker-payload) q , Where: the multi-ligand moiety comprises at least two ligands that target different cell surface molecules; The linker-payload portion has the structure: [ka] Where: R1 is independently selected from a bond and -CH2CH2C(O)-NH-; R3 is independently selected from hydrogen and -R1-R-NH-R5-D; R4 is hydrogen or [ka] and R is [ka] is selected from R5 is independently selected from a bond, -(CH2CH2O)3-CH2CH2-, -CH2C(O)-NH-CH2-, -CH2C(O)-NH-CH2C(O)-, and -CH2C(O)-; R6 independently represents a bond; [ka] is selected from Each X is independently selected from a bond, C, and O; Each m is independently 0 or 1; q is an integer from 1 to 4, D is the payload.

[0044] Another aspect of the present application discloses a conjugate compound having the following structure, or a pharma- ceutically acceptable salt thereof: Multi-ligand moiety - (linker-payload) q , Where: the multi-ligand moiety comprises at least two ligands that target different cell surface molecules; The linker-payload portion has the structure: [ka] Where: R1 is independently selected from a bond and -CH2CH2C(O)-NH-; R3 is independently selected from hydrogen and -R1-R-NH-R5-D; R4 is hydrogen or [ka] and R is [ka] and R5 each independently represents a bond, -(CH2CH2O)3-CH2CH2-, -CH2C(O)-NH-CH2-, -CH2C(O)-NH-CH2C(O)-, -CH2C(O)-, and [ka] is selected from R6 independently represents a bond; [ka] is selected from Each X is independently selected from a bond, C, and O; Each m is independently 0 or 1; q is an integer from 1 to 4, D is the payload.

[0045] The term "ligand" as used in this application may include a variety of chemical molecules or peptides that have a specific binding affinity for a selected target, which may be, for example, a cell surface receptor, a cell surface antigen, a cell, a tissue, an organ, etc. In some embodiments, a ligand may specifically bind to a protein or marker found on the target cell surface. In some embodiments, the ligand of the present application may be a ligand having a specific binding affinity for a selected target. -6 ~10 -11 M(K d In some embodiments, the ligands of the present application bind to cell surface proteins or markers with an affinity of at least 10 -7 , at least 10 -8 , at least 10 -9 M(K d In some embodiments, the ligands of the present application bind to cell surface proteins or markers with an affinity of 10 -6 Less than 10 -7 Less than 10 -8 M(K d In some embodiments, the ligands of the present application bind to cell surface proteins or markers with an affinity less than the affinity of the target cell surface protein or marker (the affinity of the ligand is at least 2-fold, 3-fold, 4-fold, 5-fold, 6-fold, 8-fold, 10-fold, 20-fold, 50-fold, 100-fold, or more than the affinity of the target cell surface protein or marker compared to the affinity of the non-target cell surface protein or marker. In some embodiments, the cell surface proteins or markers of the present application are found to be significantly higher in target cells (e.g., cancer cells) than in normal cells. The term "significant" as used in this application refers to a statistically significant difference or a significant difference that can be recognized by one of ordinary skill in the art.

[0046] A "multiligand moiety" as described herein comprises at least two ligands that target different cell surface molecules. In some embodiments, the multiligand moiety comprises three ligands, where a first ligand and a second ligand target different cell surface molecules, and the cell surface molecule targeted by the third ligand may be the same as or different from the cell surface molecule targeted by the two previous ligands. In some embodiments, the multiligand moiety may comprise four or more ligands.

[0047] The term "targeting" as used herein refers to the specific binding of a ligand or a conjugated compound containing a ligand to a cell surface molecule, which induces or promotes endocytosis of the ligand or the conjugated compound containing a ligand by the target cell, and induces or promotes enrichment of the ligand or the conjugated compound containing a ligand in the vicinity of the target cell and / or entry into the target cell.

[0048] In some embodiments, R is [ka] It is.

[0049] In some embodiments, R1 is -CH2CH2C(O)-NH-.

[0050] In some embodiments, R5 is -(CH2CH2O)3-CH2CH2-. In other embodiments, R5 is -CH2C(O)-NH-CH2C(O)-. In other embodiments, R5 is -CH2C(O)-. In some embodiments, R5 is [ka] In some embodiments, R5 is -CH2C(O)-NH-CH2-. In other embodiments, R5 is not -CH2C(O)-NH-CH2.

[0051] In some embodiments, each m is independently 0 or 1, and n is 0. In some embodiments, each m is independently 0 or 1, and n is 0. In some embodiments, m is 0, and n is independently 0 or 1. In some embodiments, m is 0, and n is 0. In some other embodiments, m is 0, n is 0, and R5 is not -CH2C(O)-NH-CH2-.

[0052] In some embodiments, R6 is [ka] In some embodiments, R6 is [ka] and X is a bond. In some embodiments, R6 is [ka] and X is O. In some embodiments, R6 is [ka] In some embodiments, R6 is [ka] and X is a bond. In some further embodiments, R6 is [ka] and X is O. In some embodiments, R6 is [ka] In some embodiments, R6 is [ka] and X is a bond. In some further embodiments, R6 is [ka] and X is O.

[0053] In some embodiments, p is 0.

[0054] The term "linker" as used in this application is a molecule or moiety that covalently links a payload and a multiligand portion. The linker comprises a functional group for linking the payload and at least one ligand. In some embodiments, the functional group may contain two reactive moieties, one for linking the payload and another for linking the ligand. In some embodiments, the functional groups are different from each other. In some embodiments, the functional group comprises a group containing a mercapto-reactive moiety and an amine-reactive moiety. In some embodiments, the functional groups are the same as each other. In some embodiments, the carboxylic acid in the amino acid contained in the linker is amidated. In some embodiments, the linker comprises a short chain polyethylene glycol (e.g., containing 2-10, 2-8, 3-8, 4-8, 4-7, 4-6, or 5 repeat units). In some embodiments, the linker comprises an azide group. In some embodiments, the linker comprises an alkynyl group.

[0055] In some embodiments, before forming the linker described in the present application, the molecules for linking these payloads and ligands are linked by a Click reaction. The "click reaction" described in the present application is a type of efficient and highly selective chemical synthesis method. The click reaction connects several molecular fragments by forming an efficient linking unit, and the overall reaction process is simple, rapid, and has few by-products. Some examples of click reactions include, but are not limited to, the addition reaction of thiols with alkenes and the cyclization reaction of azides with alkynes.

[0056] In some embodiments, the linker is sufficiently stabilized to avoid inadvertent release of the payload into the blood circulation to increase the effective amount of the payload to the target cell or tissue and to avoid toxicity, in some embodiments, the linker can release the payload around or inside the target cell to effectively kill or block the function of the target cell.

[0057] In some embodiments, the linker is non-cleavable. As used herein, the term "non-cleavable linker" refers to a linker that remains essentially intact during intracellular metabolism.

[0058] In some embodiments, the linker is cleavable. In some embodiments, the cleavable functional group is sufficiently stable outside the target cell, but cleaves to release the payload after it enters the target cell. In some embodiments, the cleavable functional group has a cleavage efficiency in the target cell that is at least 10, 20, 30, 50, 100 or more times higher than that in blood or serum. In some embodiments, the cleavable linker of the present application can be cleaved by hydrolysis, enzyme-promoted reaction, or reduction reaction, or a change in pH. In some embodiments, the linker is cleavable in a particular physiological environment (e.g., an appropriate pH environment). In some embodiments, the linker can be cleaved in an acidic environment of about pH 6.5 or less, or can be cleaved by a reagent such as an enzyme. In some embodiments, the linker is sensitive to cleavage, for example, pH, redox potential, or the presence of a degrading molecule.

[0059] In some embodiments, the linker interior is linked by peptide bonds, hi some embodiments, these peptide bonds can be cleaved by proteases that are highly or specifically found around or in the target cell, such as cathepsin B in lysosomes or intracellular bodies.

[0060] In some embodiments, the linker has a structure selected from the following group: [Table 4] JPEG2024523524000119.jpg214145JPEG2024523524000120.jpg246145JPEG2024523524000121.jpg66145

[0061] The term "payload" as used in this application is a molecule or substance that is delivered to a target cell or tissue. The molecule is a molecule that has biological activity, e.g., toxicity. In some cases, the terms payload and bioactive molecule may be used interchangeably. Without limitation, a payload may be any molecule or substance intended for the diagnosis, treatment, or prevention of disease in a subject. In some embodiments, a payload as described herein may be any agent that induces a biological or medical response in a tissue, system, animal individual, or human that a researcher, veterinarian, physician, or other practitioner is looking for to prevent, inhibit, ameliorate, or treat a disease. In some embodiments, the payload has a molecular weight of about 5 kDa or less. In some embodiments, the payload has a molecular weight of about 1.5 kDa or less. In some embodiments, the payload is a drug or diagnostic agent that is deemed safe and effective for use by the appropriate drug approval and registration agency (e.g., FDA, EMEA, or NMPA).

[0062] In some embodiments, the payloads of the present application include, but are not limited to, anti-cancer drugs, radioactive substances, vitamins, anti-AIDS drugs, antibiotics, immune inhibitors, antivirals, enzyme inhibitors, neurotoxins, opioid-like drugs, modulators of cell-extracellular matrix interactions, vasodilators, antihypertensives, hypnotics, antihistamines, anticonvulsants, muscle relaxants, antiparkinsonian substances, anticonvulsants and muscle contractants, antiparasitic and / or antiprotozoan drugs, analgesics, antipyretics, steroids and nonsteroidal anti-inflammatory drugs, antiangiogenic factors, antisecretory factors, anticoagulants and / or antithrombotic agents, local anesthetics, prostaglandins, antidepressants, antipsychotics, antiemetics, or imaging agents.

[0063] In some embodiments, the payload of the present application has a free amino or carboxyl group before being linked to the conjugate compound of the present application, and the payload is coupled to the conjugate compound by an acylation reaction or click reaction between the amino or carboxyl group and a group of a corresponding moiety (e.g., a linker) of the conjugate compound.

[0064] In some embodiments, the conjugate compound or a pharma- ceutically acceptable salt thereof comprises one, two, three, four or more payloads. In some embodiments, the payload of the present application is a small molecule compound, a nucleotide (e.g., DNA, plasmid DNA, RNA, siRNA, antisense oligonucleotide, or nucleic acid aptamer, etc.), a peptide, or a protein (e.g., an enzyme). In some embodiments, the payload is a small molecule compound or a peptide.

[0065] In some embodiments, the peptide as a payload contains at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 18, or 20 amino acid residues. In some embodiments, the peptide as a payload contains at most 4, 5, 6, 7, 8, 9, 10, 12, 15, 18, or 20 amino acid residues.

[0066] A "small molecule compound" as used herein is a compound having a molecular weight of about 2 kDa or less. In some embodiments, the small molecule compound has a molecular weight of about 1.5 kDa or less. In some embodiments, the small molecule compound has a molecular weight of about 1 kDa, 800 Da, 700 Da, 600 Da, or 500 Da or less. In some embodiments, the small molecule compound of the present application is selected from the following group: camptothecin and any derivatives thereof (e.g., SN38, Dx, or Dxd), maytansine and any derivatives thereof, radioactive metal complex compounds, cyclooxygenase-2 inhibitors and any derivatives thereof (e.g., celecoxib), paclitaxel and any derivatives thereof, epothilone and any derivatives thereof, bleomycin and any derivatives thereof, dactinomycin and any derivatives thereof, plicamycin and any derivatives thereof, and mitomycin C and any derivatives thereof. In some preferred embodiments, the small molecule compound is camptothecin and any derivatives thereof. In some preferred embodiments, the camptothecin is exatecan. In some embodiments, the small molecule compounds described herein are drugs for alleviating or treating cancer. In some embodiments, the small molecule compounds described herein are drugs for alleviating or treating autoimmune diseases.

[0067] The term "camptothecin" as used in this application is a cytotoxic alkaloid derived mainly from Camptotheca campestris of the Cornaceae family, which exhibits strong antitumor activity. Camptothecin and its derivatives in this application include currently existing or subsequently produced camptothecin and its derivatives. Camptothecin and its derivatives in this application include, but are not limited to, camptothecin, irinotecan, SN38, SN22, Dxd, exatecan (DX-8951), topotecan, GI-147211C, tropotecan, 9-aminocamptothecin, 7-hydroxymethylcamptothecin, 7-aminomethylcamptothecin, 10-hydroxycamptothecin, (20S)-camptothecin, 9-nitrocamptothecin, dimatecan, karenitecin, silatecan, retotecan, esatecan, difluotecan, belotecan, retotecan and S39625. In some embodiments, the small molecule compound is SN38, SN22, Dxd, and exatecan (DX-8951). In some embodiments, the small molecule compound is lactate-exatecan. In some embodiments, the small molecule compound is exatecan (DX-8951).

[0068] In some embodiments, each D is independently [ka] is selected from.

[0069] In some embodiments, the cell surface molecule is selected from the group consisting of TRPV6, FOLR1, PSMA, SSTR2, PD-L1, PD1, Her2, Trop2, Her3, 4-BBL, 4-1BB, CD70, CD27, CD155, CD122, CD113, CD28, CD86 / 80, CD160, ICOSL, ICOS, CD40, CD40L, OX40, OX40L, GITRL, GITR, NECTIN4, LRP1, GLUT1, EGFR1, AXL, CD44, Claudin18.2, APN, DLL3, CEACAM5, FZD10, T The present invention is selected from FRC, MET, IGFR1, CCKBR, LFA1, GPR87, GM-CSF, GM-CSFR, TIM3, TLR family, HHLA2, MHCII antigen, TCR, CTLA-4, IGIT, Galectin-3, Galectin-9, TIM-3, HVEM, BTLA, VISTA, phosphatidylserine, LAG3, LILRB4, SIGLEC15, NKG2A, NKG2D, SLAMF7, KIR2DL1, KIR2DL2, KIR2DL3, FGFR1, FGFR2, FGFR4 and NeuGcGM3.

[0070] In some embodiments, the cell surface molecule is selected from TRPV6, FOLR1, PSMA, and SSTR2.

[0071] In some embodiments, the cell surface molecules are TRPV6 and FOLR1, PSMA and FOLR1, or SSTR2 and FOLR1, respectively. In some preferred embodiments, the cell surface molecules are TRPV6 and FOLR1, respectively.

[0072] In some embodiments, the FOLR1 targeting ligand is selected from folic acid or an analog thereof, in some preferred embodiments, the folic acid analog is selected from 5-methyltetrahydrofolic acid, 5-formyltetrahydrofolic acid, methotrexate, and 5,10-methylenetetrahydrofolic acid.

[0073] In some embodiments, the ligand that targets SSTR2 is selected from octreotide and any analogues thereof.

[0074] In some embodiments, the ligand moiety comprises three or more ligands that target cell surface molecules, hi some preferred embodiments, the cell surface molecules are selected from TRPV6, FOLR1, PSMA, and SSTR2.

[0075] TRPV6 is a transient receptor potential cation channel subfamily V member 6, a highly selective transmembrane transport channel for calcium ions, which mediates the active transport of calcium ions from outside the cell to inside the cell. In normal human kidneys, gastrointestinal tracts, pancreas, mammary glands, salivary glands, etc., it is mainly expressed in intestinal epithelial cells and is involved in the transport of calcium ions into cells, so that when the number or function of TRPV6 channels changes, it can cause changes in the regulation of calcium ions, and even lead to abnormalities in the structure or function of the associated tissues and organs. Compared with normal tissues, the expression of TRPV6 is significantly increased in malignant tumors such as breast cancer, bile duct cancer, ovarian cancer, lung squamous cell carcinoma, and prostate cancer, and its abnormal expression may be related to the formation and progression of tumors.

[0076] FOLR1 is a glycoprotein anchored by glycosylphosphatidylinositol (GPI), which binds folate with namol affinity, thereby promoting receptor-mediated endocytosis. Rapidly growing solid malignant tumors, including ovarian and lung cancer, both of which are dependent on folate for metabolism and nucleic acid synthesis. In some embodiments, the targeting molecule described in the present application comprises a ligand that targets FOLR1.

[0077] PSMA is a type II transmembrane glycoprotein present in the membrane of prostate epithelial cells, consisting of 750 amino acids, including 19 amino acids in the intracellular domain, 24 amino acids in the transmembrane domain, and 707 amino acids in the extracellular domain. Prostate-specific membrane antigen is expressed in normal prostate epithelial cells, but its expression level is much higher in prostate cancer cells. Compared with prostate-specific antigen used in conventional clinical tests, prostate-specific membrane antigen is a more sensitive and specific tumor marker for prostate cancer, and is especially highly expressed in hormone-refractory prostate cancer and metastatic lesions of prostate cancer, and has high sensitivity and specificity in distinguishing prostate cancer from other types of malignant tumors. At the same time, among various non-prostate-derived solid tumors (such as lung cancer, bladder cancer, gastric cancer, pancreatic cancer, renal cancer, and colon cancer), prostate-specific membrane antigen is also highly specifically expressed in tumor vascular endothelial cells.

[0078] SSTR2 is somatostatin receptor-2, a G protein-coupled receptor that can be activated by somatostatin or its synthetic analogues. SSTR2 is one of the five subtypes of somatostatin receptors and is thought to be related to tumor progression. Somatostatin or somatostatin analogues can suppress tumor cell proliferation via SSTR2.

[0079] In some embodiments, the ligands targeting different cell surface molecules are linked directly to each other or linked to each other via a spacer region. In some embodiments, the spacer region is composed of amino acids. In some preferred embodiments, the spacer region is composed of natural or unnatural amino acids. In some further preferred embodiments, the spacer region is glycine. In some embodiments, the spacer region is Arg-Arg, Ala-Ser-Asn, Ala-Ala-Ala, Ser-Ser-Arg, Pro-Arg, and Pro-Leu-Gly. In some embodiments, the spacer region can be cleaved or reductively cleaved by a protease in a particular physiological environment. In some embodiments, the spacer region can be cleaved by a protease that is specifically expressed or expressed by the target cell.

[0080] "Cleavable" or "cleavage" as used herein includes metabolic or reactive processes carried out on a conjugated compound according to the present application that disrupts the linker between the payload and the multi-ligand moiety, or the spacer region between the ligands, to release the free payload or ligand.

[0081] In some embodiments, the ligand moiety has the structure: [Table 5] JPEG2024523524000124.jpg227159JPEG2024523524000125.jpg214161JPEG2024523524000126.jpg80156

[0082] In some embodiments, q is 1. In some embodiments, q is 2. In some embodiments, q is 3. In some embodiments, q is 4.

[0083] One aspect of the present application discloses a conjugate compound or a pharma- ceutically acceptable salt thereof selected from the following: [Table 6] JPEG2024523524000128.jpg219158JPEG2024523524000129.jpg222158JPEG2024523524000130.jpg229158 JPEG2024523524000131.jpg224158JPEG2024523524000132.jpg227158JPEG2024523524000133.jpg226158 JPEG2024523524000134.jpg221158JPEG2024523524000135.jpg222158JPEG2024523524000136.jpg224158 JPEG2024523524000137.jpg222158JPEG2024523524000138.jpg227158JPEG2024523524000139.jpg226158 JPEG2024523524000140.jpg221158JPEG2024523524000141.jpg225158JPEG2024523524000142.jpg216158 JPEG2024523524000143.jpg221158JPEG2024523524000144.jpg228158JPEG2024523524000145.jpg228158 JPEG2024523524000146.jpg223158JPEG2024523524000147.jpg221158JPEG2024523524000148.jpg224158 JPEG2024523524000149.jpg219158JPEG2024523524000150.jpg223158JPEG2024523524000151.jpg224158 JPEG2024523524000152.jpg222158JPEG2024523524000153.jpg220158JPEG202 4523524000154.jpg222158JPEG2024523524000155.jpg224158JPEG20245235240 00156.jpg218158JPEG2024523524000157.jpg222158JPEG2024523524000158.j pg225158JPEG2024523524000159.jpg226158JPEG2024523524000160.jpg225158

[0084] Another aspect of the present application discloses a pharmaceutical composition, comprising a conjugate compound described herein or a pharma- ceutical acceptable salt thereof, and a pharma- ceutical acceptable vector. In some embodiments, the pharmaceutical composition described herein is for intravenous, subcutaneous, oral, intramuscular, or intraventricular administration.

[0085] As used herein, the term "pharmacologically acceptable" means, within the scope of reasonable medical judgment, applicable for contact with the cells of humans and other animals without undue toxicity, irritation, allergic response, or the like, and commensurate with a reasonable benefit / risk ratio.

[0086] The term "pharmaceutically acceptable salts" as used herein refers to the relatively non-toxic, inorganic and organic acid addition salts, and base addition salts of the conjugate compounds of the present application. Representative acid addition salts include hydrobromide, hydrochloride, sulfate, hydrogen sulfate, phosphate, nitrate, acetate, oxalate, pentanoate, oleate, palmitate, stearate, laurate, borate, benzoate, lactate, phosphate, toluenesulfonate, citrate, maleate, fumarate, succinate, tartrate, naphthylate, methanesulfonate, glucoheptanoate, lactose, sulfamate, malonate, salicylate, propionate, methylene-bis-b-hydroxynaphthoate, roncholate, hydroxyethylsulfonate, di-p-toluyltartrate, methanesulfonate, ethanesulfonate, benzenesulfonate, p-toluenesulfonate, cyclohexylsulfamate, quinacyl laurylsulfonate, etc. Base addition salts include pharma- ceutically acceptable metal and amine salts. Suitable metal salts include the sodium, potassium, calcium, barium, zinc, magnesium and aluminum salts, with the sodium and potassium salts being preferred in some embodiments.Suitable inorganic base addition salts are prepared from metal bases, such as sodium hydride, sodium hydroxide, potassium hydroxide, calcium hydroxide, aluminum hydroxide, lithium hydroxide, magnesium hydroxide, and zinc hydroxide. Suitable amine base addition salts are prepared from amines which are sufficiently basic to form stable salts, and preferably the following amines which are commonly used in medicinal chemistry because of their low toxicity and acceptability for medical use: ammonia, ethylenediamine, N-methylglucosamine, lysine, arginine, ornithine, choline, N,N'-dibenzylethylamine ... These include diamine, chloroprocaine, diethanolamine, procaine, N-benzylphenylethylamine, diethylamine, piperazine, trimethylolaminomethane, tetramethylammonium hydroxide, triethylamine, dibenzylamine, diphenylhydroxymethine, dehydroabietylamine, N-ethylpiperidine, benzylamine, tetramethylammonium, tetraethylammonium, methylamine, dimethylamine, trimethylamine, ethylamine, basic amino acids (e.g., lysine and arginine), and dicyclohexylamine.

[0087] The term "pharmaceutical acceptable vector" as used in this application refers to a pharmaceutically acceptable solvent, suspension, or any other pharmaceutically inert carrier that does not interfere with the structure and properties of the conjugate compound and is used to deliver the conjugate compound according to the present application to a subject. Some such vectors allow the conjugate compound to be prepared into, for example, tablets, pills, capsules, liquids, gels, sugar slurries, slurries, suspensions, and soft tablets for oral ingestion by a subject. Some such vectors allow the conjugate compound to be prepared into a formulation for injection, infusion, or topical administration.

[0088] Pharmaceutically acceptable vectors for use in pharmaceutical compositions according to the present application can include, for example, pharma- ceutically acceptable liquid, gel, or solid vectors, aqueous carrier agents (e.g., sodium chloride injection, Ringer's injection, isotonic dextrose injection, sterile water injection, or dextrose and lactated Ringer's injection), non-aqueous carrier agents (e.g., fixed oils of vegetable origin, cottonseed oil, corn oil, sesame oil, or peanut oil), antibacterial agents, isotonicity agents (e.g., sodium chloride or dextrose), buffers (e.g., phosphate or citrate buffers), antioxidants (e.g., sulfate, glycerol, tert-butyl ether ... Examples of suitable ingredients include, but are not limited to, sodium bicarbonate), anesthetics (e.g., procaine hydrochloride), suspending / dispersing agents (e.g., sodium carboxymethylcellulose, hydroxypropylmethylcellulose or polyvinylpyrrolidone), chelating agents (e.g., EDTA (ethylenediaminetetraacetic acid) or EGTA (ethylene glycol tetraacetic acid)), emulsifying agents (e.g., polysorbate 80 (Tween 80)), diluents, adjuvants, excipients, or non-toxic auxiliary substances, other ingredients known in the art, or various combinations thereof. Suitable ingredients may include, for example, fillers, binders, buffers, preservatives, lubricants, flavoring agents, thickening agents, coloring agents, or emulsifying agents.

[0089] In some embodiments, the pharmaceutical composition is an injectable preparation. Injectable preparations include sterile aqueous solutions or dispersions, suspensions or emulsions. Under all circumstances, injectable preparations should be sterile and fluid to facilitate injection. Injectable preparations must be stable under the conditions of production and storage and must be free of contamination by microorganisms such as bacteria and fungi. The vector may be a solvent or dispersion medium containing, for example, water, ethanol, polyol (e.g., glycerol, propylene glycol, and liquid polyethylene glycol, etc.) and suitable mixtures thereof, and / or vegetable oils. Injectable preparations should maintain a suitable fluidity. Suitable fluidity can be maintained, for example, by using a coating such as lecithin, by using a surfactant, and the like. Microbial inhibition can be achieved by various antibacterial and antifungal agents, such as parabens, chlorobutanol, phenol, sorbic acid, thimerosal, and the like.

[0090] In some embodiments, the pharmaceutical composition is an oral dosage formulation, including, but not limited to, capsules, flat capsules, pills, tablets, lozenges (using a flavored base, typically sucrose and gum arabic or gum tragacanth), powders, granules, or solutions or suspensions in aqueous or non-aqueous liquids, or oil-in-water or water-in-oil liquid emulsions, or elixirs or syrups, or soft lozenges (using an inert base, such as gelatin and glycerin, or sucrose and gum arabic) and / or mouthwashes.

[0091] In solid dosage forms for oral administration (e.g., capsules, tablets, pills, dragees, powders, granules, etc.), the conjugate compound is mixed with one or more pharma- ceutically acceptable vectors, such as sodium citrate or dicalcium phosphate, and / or any one of the following: (1) fillers or extenders, such as starch, lactose, sucrose, glucose, mannitol, and / or silicic acid; (2) binders, such as carboxymethylcellulose, alginates, gelatin, polyvinylpyrrolidone, sucrose, and / or gum arabic; (3) humectants, such as gum arabic; lycerin, (4) disintegrating agents, such as agar-agar, calcium carbonate, potato starch or tapioca starch, alginic acid, some silicates and sodium carbonate, (5) solution retardants, such as paraffin, (6) absorption accelerators, such as quaternary ammonium compounds, (7) wetting agents, such as acetyl alcohols and monoglycerides, (8) absorbents, such as kaolin and bentonite, (9) lubricants, such as talc, calcium stearate, magnesium stearate, solid polyethylene glycols, sodium lauryl sulfate and mixtures thereof, and (10) coloring agents.

[0092] In the liquid dosage form for oral administration, the conjugate compound is mixed with any one of pharma- ceutically acceptable emulsions, microemulsions, solutions, suspensions, syrups, and elixirs. In addition to the conjugate compound, the liquid dosage form may contain inert diluents commonly used in the art, such as water or other solvents, solubilizers and emulsifiers, such as ethanol, isopropyl alcohol, ethyl carbonate, ethyl acetate, benzyl alcohol, benzyl benzoate, isopropyl alcohol, 1,3-butylene glycol, oils (especially cottonseed oil, peanut oil, corn oil, olive oil, castor oil, and sesame oil), glycerol, tetrahydrofurfuryl alcohol, polyethylene glycols, and dehydrated sorbitan fatty acid esters, and mixtures thereof. In addition to the inert diluents, the oral composition may further contain adjuvants, such as wetting agents, emulsifiers and suspending agents, sweeteners, flavoring agents, coloring agents, flavoring agents, and preservatives.

[0093] In some embodiments, the pharmaceutical composition is an oral spray formulation or a nasal spray formulation. Spray formulations include, but are not limited to, aqueous aerosols, non-aqueous suspensions, liposome formulations, or solid granule formulations. Aqueous aerosols are prepared by mixing an aqueous solution or suspension of the drug with a pharma- ceutically acceptable general vector and stabilizer. The vector and stabilizer vary based on the needs of the specific compound, but generally include non-ionic surfactants (Tween or polyethylene glycol), oleic acid, lecithin, amino acids such as glycine, buffer solutions, salts, sugars or sugar alcohols. Aerosols are generally prepared with isotonic solutions and can be delivered by spraying.

[0094] In some embodiments, the pharmaceutical composition may be used in combination with one or more other pharmaceutical agents. In some embodiments, the pharmaceutical composition contains at least one other pharmaceutical agent. In some embodiments, the other pharmaceutical agent is an anti-neoplastic agent, a cardiovascular agent, an anti-inflammatory agent, an anti-viral agent, a gastrointestinal agent, a nervous system agent, a respiratory system agent, an immune system agent, a skin disease agent, a metabolic agent, or the like.

[0095] In some embodiments, the pharmaceutical composition may be administered to a subject in need thereof via a suitable route, including, but not limited to, oral administration, injection (e.g., intravenous, intramuscular, subcutaneous, intradermal, intraventricular, intraspinal, intrapleural, intraperitoneal injection, etc.), mucosal (e.g., intranasal, buccal, etc.), sublingual, rectal, transdermal, ocular, and pulmonary administration. In some embodiments, the pharmaceutical composition may be administered intravenously, subcutaneously, orally, intramuscularly, or intraventricularly.

[0096] Due to the nature of some payloads, e.g., high toxicity, high hydrophilicity, it is desirable to deliver the payload more specifically and more efficiently to a subject in need thereof. For example, in cancer treatment, it is desirable to deliver chemotherapeutic agents specifically to cancer cells without causing toxicity to normal cells. Therefore, another aspect of the present application discloses a method of delivering a payload to a subject in need thereof, the method comprising administering to the subject a therapeutically effective amount of a conjugate compound according to the present application, or a pharma- ceutically acceptable salt thereof, or a pharmaceutical composition according to the present application.

[0097] Another aspect of the present application discloses a method for treating a disease in a subject, the method comprising administering to the subject a therapeutically effective amount of a conjugate compound described herein or a pharma- ceutically acceptable salt thereof, or a pharmaceutical composition described herein. In some embodiments, the method further comprises administering one or more therapeutic agents in combination with the conjugate compound or a pharma- ceutically acceptable salt thereof, or the pharmaceutical composition.

[0098] Another aspect of the present application discloses the use of a conjugate compound as described herein or a pharma- ceutically acceptable salt thereof, or a pharmaceutical composition as described herein, in the manufacture of a medicament for treating a disease in a subject.

[0099] The term "therapeutically effective amount" as used in this application refers to an amount of a conjugate compound or its pharma- ceutically acceptable salt or pharmaceutical composition that alleviates to some extent one or more symptoms of a disease or condition in a subject, partially or completely restores to normal one or more physiological or biochemical parameters associated with or causing the disease or condition, and / or reduces the likelihood of the onset of the disease or condition. This amount will generally vary depending on a variety of factors, which one of ordinary skill in the art can determine and account for based on the scope of the present specification. These include, but are not limited to, the particular subject and its age, weight, height, general physical condition and medical history, the particular compound used, and its formulation vector and selected route of administration, and the nature and severity of the condition being treated.

[0100] In some embodiments, the amount of the conjugate compound or its pharma- ceutically acceptable salt, or pharmaceutical composition is sufficient to inhibit a disease or condition in a subject, or to prophylactically inhibit or prevent the onset of a disease or condition. A therapeutically effective amount may vary depending on the subject, but generally ranges from 0.01 to 150 mg / kg, e.g., 0.01 to 140 mg / kg, 0.01 to 130 mg / kg, 0.01 to 120 mg / kg, 0.01 to 110 mg / kg, 0.01 to 0 mg / kg, or 0.01 to 0 mg / kg. 0.01-90 mg / kg, 0.01-80 mg / kg, 0.01-70 mg / kg, 0.01-60 mg / kg, 0.01-50 mg / kg, 0.01-40 mg / kg, 0.01-30 mg / kg, 0.01-20 mg / kg, 0.01-10 mg / kg, 0.01-5 mg / kg, 0.01-4 mg / kg, 0.01-3 mg / kg, 0.01-2 mg / kg, 0.01-1 mg / kg, 0.01-0.1 mg / kg. In some embodiments, the conjugate compound of the present application or a pharma- ceutical acceptable salt thereof or a pharmaceutical composition thereof is administered in a dose range of 1 to 150 mg / kg of the conjugate compound. In some embodiments, the conjugate compound of the present application or a pharma- ceutically acceptable salt thereof or a pharmaceutical composition thereof is administered at a dose of 1 to 25 mg / kg, 1 to 50 mg / kg, 1 to 75 mg / kg, 1 to 100 mg / kg, 1 to 125 mg / kg, 1 to 150 mg / kg, 25 to 75 mg / kg, 25 to 50 mg / kg, 25 to 40 mg / kg, 25 to 30 mg / kg, 1 to 20 mg / kg, 1 to 15 mg / kg, 1 to 10 mg / kg, 1 to 5 mg / kg, or 1 to 3 mg / kg of the conjugate compound. In some embodiments, the conjugate compound of the present application or a pharma- ceutically acceptable salt thereof or a pharmaceutical composition thereof is administered at a dose of 1 mg / kg, 3 mg / kg, 10 mg / kg, 25 mg / kg, 50 mg / kg, 75 mg / kg, 100 mg / kg, or 150 mg / kg of the conjugate compound. In some embodiments, the conjugate compound or pharma- ceutically acceptable salt thereof or pharmaceutical composition thereof of the present application may be administered daily (e.g., once, twice, three or four times a day), or every other day or every multiple days (e.g., once every week, every two weeks, every three weeks, every month, every quarter).In some embodiments, the administration frequency of the conjugate compound or its pharma- ceutically acceptable salt or its pharmaceutical composition described herein is once a week, twice a week, three times a week, once every three days, once every two days, once a day, twice a day, or three times a day. In some embodiments, the administration frequency of the conjugate compound or its pharma- ceutically acceptable salt or its pharmaceutical composition described herein is once a week. In some embodiments, the administration frequency of the conjugate compound or its pharma- ceutically acceptable salt or its pharmaceutical composition described herein is three times a day. The therapeutically effective amount described herein may be equal to any value within the above numerical range, including the end points of the range.

[0101] The term "subject" as used in this application refers to humans and non-human animals. Non-human animals include all vertebrates, e.g., mammals and non-mammals. The subject may be a livestock animal, e.g., cows, pigs, sheep, poultry and horses, or a farm animal, e.g., dogs and cats. The subject may be male (e.g., man) or female (e.g., woman), and may be an elderly person, an adult, an adolescent, a child or an infant. The human may be of Caucasian, African, Asian, Semitic, or other racial background, or a mixture of these racial backgrounds.

[0102] In some embodiments, the disease described in the present application is selected from the following group: cancer, immune disease, metabolic disease, and neurological disease. In some embodiments, the cancer is selected from pancreatic cancer, biliary tract cancer, liver cancer, breast cancer, thyroid cancer, colon cancer, esophageal cancer, lung cancer, kidney cancer, leukemia, ovarian cancer, gastric cancer, uterine cancer, endometrial cancer, colon cancer, testicular cancer, skin cancer, prostate cancer, lymphoma, and multiple myeloma. In some embodiments, the immune disease is an autoimmune disease, preferably, the autoimmune disease is selected from connective tissue disease, systemic sclerosis, rheumatoid arthritis, and systemic lupus erythematosus. The metabolic disease is selected from diabetes, gout, obesity, hypoglycemia, hyperglycemia, and dyslipidemia. In some embodiments, the neurological disease is selected from Alzheimer's disease, Parkinson's disease, Huntington's disease, head injury, multiple sclerosis, dizziness, coma, and epilepsy.

[0103] In some embodiments, the methods of the present application further comprise administering one or more therapeutic agents in combination with said conjugate compound or a pharma- ceutically acceptable salt thereof, or said pharmaceutical composition.

[0104] The following will describe the present application in more detail through specific examples. The following examples are provided for illustrative purposes only and are not intended to limit the present invention in any manner. Those skilled in the art will readily recognize that various non-critical parameters can be changed or modified to produce essentially the same results. Working Example

[0105] The following examples are used to better illustrate the present invention and should not be understood as limiting the scope of the present invention. All specific compositions, materials and methods described below, in whole or in part, are within the scope of the present invention. These specific compositions, materials and methods are not used to limit the present invention, but to illustrate that certain embodiments are within the scope of the present invention. Those skilled in the art can develop equivalent compositions, materials and methods without departing from the scope of the present invention without additional creativity. It should be understood that various modifications made to the method of the present invention are still included within the scope of the present invention. The inventor intends that such modifications are included within the scope of the present invention. Example 1 Preparation of the Multiligand Moiety

[0106] 2. Preparation of Ligand-01 [ka]

[0107] The peptide sequence Pteroic acid-Glu-Cys-Lys-Glu-Phe-Leu-His-Pro-Ser-Lys-Val-Asp-Leu-Pro-Arg-OH was synthesized using solid phase synthesis Fmoc chemical amino resin. The resin is loaded into a solid-phase reaction column, DMF is added, nitrogen gas is bubbled into the solvent, the resin is swollen for 30 minutes, Fmoc-Arg-OH, DCC and DMAP are added, and the reaction is carried out at 25°C for 3 hours. Then, the resin is sealed with acetic anhydride and pyridine for 1 hour, and washed three times with DMF. The Fmoc protecting group on the resin is removed with DBLK, and the resin is washed five times with DMF. Fmoc-Pro-OH and HOBt are weighed and dissolved in DMF. DIC is added to the above solution under an ice-water bath at 0°C, and the solution is mixed and activated for 5 minutes. The solution is added to the above reaction column, and the reaction is carried out for 3 hours. Then, the solvent is extracted and dried, and the resin in the reaction column is washed three times. Then, the Fmoc protecting group was removed with DBLK, and the above operation was repeated, and Fmoc-Leu-OH, Fmoc-Asp(OtBu)-OH, Fmoc-Val-OH, Fmoc-Lys(Boc)OH, Fmoc-Ser(tBu)-OH, Fmoc-Pro-OH, Fmoc-His(Trt)-OH, Fmoc-Leu-OH, Fmoc-Phe-OH, Fmoc-Glu(OtBu)-OH, Fmoc-Lys(Boc)-OH, Fmoc-Cys(Trt)-OH, Fmoc-Glu-OtBu and pteroic acid were coupled in order according to the structure. After the resin was cleaved with the crushing solution, it was filtered, the crushing solution was poured into MTBE, the solid matter was precipitated, washed with MTBE, and a crude product was obtained, and the crude product was purified by Pre-HPLC and produced to obtain Ligand01.

[0108] Similarly, Ligand02, Ligand03, Ligand04, Ligand05 and Ligand06 can be obtained by steps similar to those described above. Example 2 Preparation of conjugate compounds

[0109] 1. Synthesis of conjugate compound CR194AR

[0110] Step 1: Manufacturing CR194AQ [ka]

[0111] CR19419 (1.0 eq, see diagram for structure) was weighed into a 50 mL one-neck flask and dissolved in DMF, then CR194FJ (1.0 eq, see diagram for structure), HATU (1.1 eq) and DIPEA (2.5 eq) were added and stirred at 25° C. for 4 hours. After completion of the reaction, the reaction solution was poured into aqueous acetic acid, extracted three times with ethyl acetate, the organic phase was washed with water, washed with saturated sodium chloride, and the organic phase was dried to obtain CR194AQ (see diagram for structure).

[0112] Step 2: Making the CR194AR [ka]

[0113] CR194AQ (1.0 eq) was weighed into a 50 mL one-neck flask, and dissolved in a 1:1 mixture of DMF and water, then CR194K0 (1.2 eq, see diagram for structure) and CuI (1.0 eq) were added and stirred for 4 hours at 25° C. After the reaction was completed, the reaction solution was submitted to manufacturing for purification, and the pure product was produced and freeze-dried to obtain CR194AR.

[0114] 2. Synthesis of conjugate compound CR194X3

[0115] Step 1: Manufacturing the CR194X0 [ka]

[0116] CR19419 (1.0 eq, see the diagram for the structure) was weighed into a 50 mL one-neck flask, dissolved in DMF, and then CR194W9 (1.0 eq, see the diagram for the structure), HATU (1.1 eq) and DIPEA (2.5 eq) were added and stirred for 4 hours at 25° C. After the reaction was completed, the reaction solution was poured into acetic acid water to precipitate a solid, which was then filtered, washed with acetic acid water for the cake, and dried to obtain CR194X0 (see the diagram for the structure).

[0117] Step 2: Manufacturing CR194X1

[0118] CR194X0 (1.0 eq, see the diagram for the structure) was weighed into a 50 mL one-neck flask, dissolved in DMF, cooled in an ice bath, and then DBU (1.1 eq) was added and reacted in an ice bath for 3 hours. After completion of the reaction, the reaction solution was poured into MTBE to precipitate a solid, which was then filtered. The cake was washed three times with MTBE and vacuum dried to obtain CR194X1 (see the diagram for the structure).

[0119] Step 3: Manufacturing CR194X2 [ka]

[0120] CR194X1 (1.0 eq) was weighed into a 50 mL one-neck flask and dissolved in DMF, then CR19424 (1.0 eq, see diagram for structure), HATU (1.1 eq) and DIPEA (2.5 eq) were added and stirred for 4 hours at 25° C. After completion of the reaction, the reaction solution was poured into aqueous acetic acid, extracted three times with ethyl acetate, the organic phase was washed with water and with saturated sodium chloride, and the organic phase was dried to obtain CR194X2 (see diagram for structure).

[0121] Step 4: Manufacturing CR194X3 [ka]

[0122] CR194X2 (1.0eq) was weighed into a 50mL single-neck flask, dissolved by adding methanol, then added 10mM PBS buffer, cooled in ice bath and stirred for 10 minutes, resulting in a white suspension, adjusted to pH=8-9, added 0.1M NaH2PO4 pH adjusted to pH=7, weighed CR19101 (structure see diagram) and added in batches, controlled to pH=7, reacted and stirred in ice bath for 15 minutes, and used HPLC to completely react the controlled raw materials, then submitted the reaction solution to manufacture for purification and freeze-drying to obtain CR194X3 (structure see diagram).

[0123] 3. Synthesis of conjugate compound CR194AX

[0124] Step 1: Manufacturing the CR194CZ [ka]

[0125] CR19419 (1.0 eq) was weighed into a 50 mL one-neck flask, dissolved in DMF, and then CR194BF (1.0 eq), HATU (1.1 eq) and DIPEA (2.5 eq) were added and stirred for 4 hours at 25° C. After the reaction was completed, the reaction solution was poured into aqueous acetic acid, extracted three times with ethyl acetate, and the organic phase was washed with water and saturated sodium chloride, and the organic phase was dried to obtain CR194CZ.

[0126] Step 2: Building the CR194AW [ka]

[0127] CR194CZ (1.0 eq) was weighed into a 50 mL one-neck flask, and a TFA:DCM=1:1 solution was added and reacted for 5 hours. After the reaction was completed, the reaction solution was poured into MTBE to precipitate a solid, which was then filtered. The cake was washed three times with MTBE and dried in vacuum to obtain CR194AW.

[0128] Step 3: Manufacturing the CR194AX [ka]

[0129] The synthesis of CR194AX was realized using solid-phase synthesis Fmoc chemical amino resin. The resin was loaded into a solid-phase reaction column, DMF was added, nitrogen gas was bubbled into the solvent, the resin was swollen for 30 minutes, Fmoc-Arg-OH, DCC and DMAP were added, and the reaction was carried out at 25°C for 3 hours, after which it was sealed with acetic anhydride and pyridine for 1 hour, washed three times with DMF, the Fmoc protecting group on the resin was removed with DBLK, and washed five times with DMF, Fmoc-Pro-OH and HOBt were weighed and dissolved in DMF, DIC was added to the above solution under an ice-water bath at 0°C, mixed and activated for 5 minutes, the solution was added to the above reaction column, and after reaction for 3 hours, the solvent was extracted and dried, and the resin in the reaction column was washed three times. Then, the Fmoc protecting group was removed with DBLK, and the above procedure was repeated to obtain Fmoc-Leu-OH, Fmoc-Asp(OtBu)-OH, Fmoc-Val-OH, Fmoc-Lys(Boc)OH, Fmoc-Ser(tBu)-OH, Fmoc-Pro-OH, Fmoc-His(Trt)-OH, Fmoc-Leu-OH, Fmoc-Phe-OH, Fmoc-Glu(OtBu)-OH, Fmoc-Lys(dde)-OH, Fmoc-Cys(Trt ... Moc-Glu-OtBu and pteroic acid were coupled, and the dde protecting group was protected with a 4% hydrazine hydrate / DMF solution. The mixture was then washed five times with DMF. CR194AW, HBTU, and DIEA were added and reacted for 3 hours. After the reaction was completed, the mixture was washed with DMF, DCM, and MeOH. The resin was dried by blowing nitrogen. The resin was cleaved with the crushing liquid, and then filtered. The crushing liquid was poured into MTBE to precipitate a solid, which was then washed with MTBE to obtain a crude product. The crude product was purified by pre-HPLC to obtain CR194AX.

[0130] 4. Synthesis of conjugate compound CR194AB [ka]

[0131] CR194X2 (1.0eq) was weighed into a 50mL one-neck flask, dissolved by adding methanol, then added 10mM PBS buffer, cooled in an ice bath and stirred for 10 minutes to give a white suspension, adjusted to pH=8-9, added 0.1M NaH2PO4 to adjust the pH to pH=7, weighed and added CR194H4 (structure, see diagram), controlled to pH=7, reacted and stirred in an ice bath for 15 minutes, and the control raw material was completely reacted by HPLC, the reaction solution was submitted to production for purification and freeze-drying to obtain CR194AB (structure, see diagram).

[0132] 5. Synthesis of conjugate compound CR194A2

[0133] Step 1: Making the CR19498 [ka]

[0134] SN38 (1.0 eq) was weighed into a 50 mL one-neck flask and dissolved in DMF, then (Boc)2O (1.2 eq) and DIPEA (1.5 eq) were added and stirred at room temperature overnight. The control raw material was completely reacted by TLC, the reaction solution was poured into water, extracted with EtOAc, the organic phase was dried over anhydrous sodium sulfate, and spun under reduced pressure to obtain CR19498 (see the figure for the structure).

[0135] Step 2: Making the CR19499

[0136] CR19498 (1.0 eq) and Boc-Gly-OH (1.1 eq) were weighed into a 50 mL one-neck flask, dissolved in DMF, cooled in an ice bath, and HATU (1.1 eq), DMAP (0.1 eq) and DIPEA (2 eq) were added, then transferred to an ice bath and stirred at room temperature for 1 hour, quenched with water, extracted with EtOAc, the organic phase was dried over anhydrous sodium sulfate and vacuum spun to obtain CR19499 (see figure for structure).

[0137] Step 3: Manufacturing the CR194A0 [ka]

[0138] CR19499 (1.0 eq) was weighed and dissolved in a 30% TFA dichloromethane solution, and the mixture was stirred at room temperature for 1 hour. The reaction solution was then vacuum spun to remove DCM and TFA, after which MTBE was added to precipitate a solid, which was then extracted and filtered to obtain CR194A0 (see the diagram for the structure).

[0139] Step 4: Making CR194A1 [ka]

[0140] CR194A0 (1.0 eq), CR19206 (1.05 eq), and HOBT (0.1 eq) were weighed into a 50 mL one-neck flask, dissolved in DMF, and then DIPEA (2 eq) was added and stirred at room temperature overnight. The reaction solution was submitted to production for purification and freeze-drying to obtain CR194A1 (see the diagram for the structure).

[0141] Step 5: Manufacturing CR194A2 [ka]

[0142] CR194A1 (1.0eq) was weighed into a 50mL one-neck flask, and dissolved by adding methanol. Then, 10mM PBS buffer was added, cooled in an ice bath and stirred for 10 minutes, and the pH was adjusted to 8-9. 0.1M NaH2PO4 was added to adjust the pH to pH=7. CR19101 (1.0eq) was weighed and added, and the pH was controlled to 7. The reaction was allowed to proceed with stirring in an ice bath for 15 minutes. The reaction liquid was then submitted to production for purification and freeze-drying to obtain CR194A2 (see the diagram for the structure).

[0143] 6. Synthesis of conjugate compound CR194A6

[0144] Step 1: Making the CR194A3 [ka]

[0145] CR194A0 (1.0 eq), CR19496 (1.05 eq), and HOBT (0.1 eq) were weighed into a 50 mL one-neck flask, dissolved in DMF, and then DIPEA (2 eq) was added and stirred at room temperature overnight. The reaction solution was submitted to production for purification and freeze-drying to obtain CR194A3 (see the diagram for the structure).

[0146] Step 2: Making the CR194A4 [ka]

[0147] CR194A3 (1.0 eq) was weighed and dissolved in a 30% TFA dichloromethane solution, and the mixture was stirred at room temperature for 1 hour. The reaction solution was then spun under reduced pressure to remove DCM and TFA. MTBE was then added to precipitate a solid, which was then extracted and filtered to obtain CR194A4 (see the diagram for the structure).

[0148] Step 3: Making the CR194A5 [ka]

[0149] CR19484 (1.0 eq) and CR194A4 (2.0 eq) were weighed into a 50 mL one-neck flask, dissolved in DMF, and cooled in an ice bath. Then, HATU (2.1 eq) and DIPEA (3 eq) were added and the mixture was stirred at room temperature for 2 hours. The mixture was quenched by adding 5% aqueous acetic acid to precipitate a solid, which was extracted and filtered to obtain a crude product of CR194A5, which was submitted to manufacturing for purification and freeze-dried to obtain CR194A5 (see the diagram for the structure).

[0150] Step 4: Making CR194A6 [ka]

[0151] CR194A5 (1.0eq) was weighed into a 50mL one-neck flask, and dissolved by adding methanol. Then, 10mM PBS buffer was added, cooled in an ice bath and stirred for 10 minutes, and the pH was adjusted to 8-9. 0.1M NaH2PO4 was added to adjust the pH to pH=7. CR19101 (1.0eq) was weighed and added, and the pH was controlled to 7. The reaction was allowed to proceed with stirring in an ice bath for 15 minutes, and the control raw material was completely reacted by HPLC. The reaction solution was submitted to production for purification and freeze-drying to obtain CR194A6 (see the diagram for the structure).

[0152] 7. Synthesis of conjugate compound CR19462

[0153] Step 1: Making the CR19459 [ka]

[0154] SN38 (1.0 eq) was weighed into a 50 mL one-neck flask and dissolved in DMF. Potassium carbonate (1.5 eq) and CR194B6 (1.2 eq) were then added and the mixture was heated to 50° C. and stirred for 5 hours. The reaction solution was cooled in an ice bath and quenched by adding water. The mixture was extracted with ethyl acetate. The organic phase was washed with saturated sodium chloride and dried over anhydrous sodium sulfate. The mixture was then concentrated to remove the solvent and purified using a silica gel column to obtain CR19459 (see the diagram for the structure).

[0155] Step 2: Fabricate the CR19460 [ka]

[0156] CR19459 (1.0 eq) was weighed into a 50 mL one-neck flask, 30% TFA dichloromethane solution was added, and the mixture was stirred at room temperature for 1 hour. The solvent was removed by vacuum spinning, MTBE was added, and a solid was precipitated. The solid was extracted and filtered to obtain CR19460 (see the diagram for the structure).

[0157] Step 3: Fabricate the CR19461 [ka]

[0158] CR19460 (1.0 eq), CR19206 (1.05 eq), and HOBT (1.0 eq) were weighed into a 50 mL one-neck flask, dissolved in DMF, and then DIPEA (2.0 eq) was added and stirred at room temperature overnight. The reaction solution was submitted to production for purification and freeze-drying to obtain CR19461 (see the diagram for the structure).

[0159] Step 4: Fabricate the CR19462 [ka]

[0160] CR19461 (1.0eq) was weighed into a 50mL one-neck flask, dissolved by adding methanol, then added 10mM PBS buffer, cooled in an ice bath and stirred for 10 minutes, adjusted to pH=8-9, added 0.1M NaH2PO4 to adjust the pH to pH=7, weighed and added CR19101 (1.0eq), controlled to pH=7, reacted and stirred in an ice bath for 15 minutes, and the control raw material was completely reacted by HPLC, and the reaction solution was submitted to production for purification and freeze-drying to obtain CR19462. (See the diagram for the structure).

[0161] Similar preparation methods to those described above can be employed to prepare other conjugate compounds described in this application. Example 3 Affinity Experiments

[0162] The experiment was performed according to the Reichert SPR4 instruction manual to measure the affinity of the analyte CR194AR to FOLR1 and TRPV6, respectively. Here, the CM5 chip was coupled with the ligands FOLR1 (Yiqiao Shenzhou, product number 11241-H08H) and TRPV6 (Acro, product number MAES), respectively. The experimental results are shown in Table 1 below. [Table 7]

[0163] The results showed that CR194AR, FOLR1, and TRPV6 all bound specifically and with high affinity.

[0164] Similar to the above detection method, the other conjugate compounds of the present application all had good affinity with the corresponding cell surface receptors. Example 4 Cell proliferation inhibition experiment

[0165] Sample information: CR194AR, CR194X3, CR194V5, CR194AA, CR194AB, CR194U9, CR194Z9, CR194AH, CR194AY, CR194AX and Dx.

[0166] Cell lines: HEK293T-FOLR1 (FOLR1 overexpressing stable cell line), SK-BR-3 (human breast cancer cells) and HEK293T (human pancreatic cancer cells). The protein levels of FOLR1 in different cell lines are shown in Table 2 below. [Table 8]

[0167] Key reagents: 1640 folate-free medium, fetal bovine serum, penicillin-streptomycin solution, L-glutamine and CCK8.

[0168] Experimental Procedure: (1) Cell plating: Prepare cells in advance, trypsin digest, collect counts, and plate 6 × 10 HEK293T-FOLR1 and HEK293T cells in complete cell culture medium. 3 Dilute SK-BR-3 cells to 1.5 x 10 cells / ml. 4 The cells were diluted to 100 cells / ml and plated in a 96-well plate, 100 μl of the diluted cell solution was added to each well, and negative and blank control wells were placed in each plate. The 96-well plate containing the cells was placed in a 37°C, 5% CO2 incubator and cultured overnight. (2) Dilution and sample addition: The sample was serially diluted with medium (starting concentration 30 μM, 5-fold serial dilution) to set up a total of 10 concentration steps. 50 μl per well was added to a 96-well plate after overnight incubation, triplicate wells were added, and negative and blank controls were also set up. The samples were then cultured in a 37°C, 5% CO2 incubator for 72 hours. (3) Reading the color plate: Take the CCK-8 color solution, add 15 μl (10% of the liquid volume in the well) per well, incubate at 37°C for an appropriate time (to keep the OD value within the range of 1.0 to 2.5 as much as possible), remove the lid of the culture plate from the 96-well plate, place it on a plate reader (Molecular Devices SpectraMax iD5), and read the value at 450 nm. (4) Data processing: Data were edited using SoftMax Pro 7.1, and a four-parameter fitting curve was plotted.

[0169] The experimental results are shown in Table 3 below. [Table 9]

[0170] As can be seen from Table 3, the IC values ​​of CR194AR, CR194AB, CR194U9, CR194Z9, CR194AH, CR194AY, CR194AX, CR194X3, CR194V5 and CR194AA against the cell lines HEK293T-FOLR1 and SK-BR-3, which have relatively high receptor expression levels. 50The levels of these compounds were significantly lower than those of the HEK293T cell line, which has a relatively low level of receptor expression. These compounds showed antitumor effects related to the levels of receptor expression in cells, and were found to play an important role in the process of suppressing tumor cell proliferation.

[0171] Sample information:CR194A2,CR194A6,CR194N5,CR194N9,CR194P6,CR194P3,CR194S3,CR194R8,CR194L4,CR194U7,CR194Q1,CR194Q5,CR194U9,CR194R7,Dxd,Dx and SN38.

[0172] Cell lines: HEK293T-FOLR1 (FOLR1 overexpressing stable cell line), SK-BR-3 (human breast cancer cells, FOLR1 underexpressing) and MIA PaCa-2 (human pancreatic cancer cells, FOLR1 null).

[0173] Key reagents: 1640 folate-free medium, fetal bovine serum, penicillin-streptomycin solution, L-glutamine and CCK8.

[0174] Experimental Procedure: (1) Cell plating: Prepare cells in advance, trypsin digest, collect counts, and plate SK-BR-3 cells at 3.0 × 10 in complete cell culture medium. 4 Dilute HEK293T-FOLR1 cells to 1.5 x 10 cells / ml. 4 Dilute MIA PaCa-2 cells to 2.0 x 10 cells / ml. 4 The cells were diluted to 100 cells / ml and plated in a 96-well plate, 100 μl of the diluted cell solution was added to each well, and negative and blank control wells were placed in each plate. The 96-well plate containing the cells was placed in a 37°C, 5% CO2 incubator and cultured overnight. (2) Dilution and sample addition: The sample was serially diluted with medium (starting concentration 30 μM, 5-fold serial dilution) to set up a total of 10 concentration steps. 50 μl per well was added to a 96-well plate after overnight incubation, triplicate wells were added, and negative and blank controls were also set up. The samples were then cultured in a 37°C, 5% CO2 incubator for 72 hours. (3) Reading the color plate: Take the CCK-8 color solution, add 15 μl (10% of the liquid volume in the well) per well, incubate at 37°C for an appropriate time (to keep the OD value within the range of 1.0 to 2.5 as much as possible), remove the lid of the culture plate from the 96-well plate, place it on a plate reader (Molecular Devices SpectraMax iD5), and read the value at 450 nm. (4) Data processing: Data were edited using SoftMax Pro 7.1, and a four-parameter fitting curve was plotted.

[0175] The experimental results are shown in Table 4 below. [Table 10] Example 5 Pharmacodynamic study of CR194AX, CR194X3 and CR194AR in the CDX model

[0176] Objective: To investigate the efficacy of the conjugate compounds CR194AX, CR194X3 and CR194AR in a subcutaneous allograft model of FOLR1-overexpressing 293T-FOLR1 cell line (CDX).

[0177] CDX Model: 293T-FOLR1

[0178] Experimental method: The prepared cells were inoculated subcutaneously into the right side of BALB / c-nude mice until the tumor volume reached 100-150 mm 3When the tumor was amplified, the mice were randomly divided into groups, and model control groups and treatment groups were set up. Treatment began on the first day of grouping, and the dosage was adjusted according to the mouse's latest body weight, and the tail vein was injected, with a volume of 10 μl / g. After group administration, monitoring included tumor growth and the effects of treatment on the normal behavior of the animals, including the activity of the experimental animals, feeding and drinking status, weight gain or loss, eyes, hair and other abnormal conditions. After group administration, the mice were weighed twice a week, and the weight change rate was calculated. At the same time, the long and short diameters of the tumors were measured with calipers, and the tumor volume, relative tumor growth rate, tumor volume anti-tumor rate and other indicators were calculated. The tumor volume formula is TV=0.5a×b 2 where a is the longest diameter of the tumor and b is the shortest diameter of the tumor.

[0179] The experimental results are shown in Table 5 below. As can be seen from the experimental results, the tail vein administration of test samples CR194AX, CR194X3 and CR194AR showed different degrees of tumor growth inhibition. At a medium dose (3mg / kg), CR194AX, CR194X3 and CR194AR all had a certain anti-tumor growth effect compared to the negative control group, and at a high dose (10mg / kg), all had excellent anti-tumor growth effect compared to the negative control group, and the anti-tumor effect showed dose-related relationship, and the data are shown in Table 5. [Table 11] Example 6 Pharmacodynamic study of conjugate compounds in the CDX model

[0180] Experimental Objective: To study the efficacy of conjugate compounds CR194Q1, CR194V5, CR194AH, CR194X3, CR194U9, CR194Z9, CR194AB, CR194AX, CR194AY and CR194AR in the CDX model of CFPAC-1.

[0181] CDX model: CFPAC-1 (human pancreatic cancer cells)

[0182] Experimental method: The prepared cells were inoculated subcutaneously into the right side of BALB / c-nude mice until the tumor volume reached 100-150 mm 3 When the tumors were amplified, they were randomly divided into groups, and model control groups and treatment groups were set up. Treatment began on the first day of grouping, and the dosage was adjusted according to the latest body weight of the mice, and the tail vein was injected, with a volume of 10 μl / g. After group administration, monitoring included tumor growth and the effects of treatment on the normal behavior of the animals, including the activity of the experimental animals, feeding and drinking status, weight gain or loss, eyes, hair and other abnormal conditions. After group administration, the mice were weighed twice a week, and the weight change rate was calculated. At the same time, the long and short diameters of the tumors were measured with calipers, and the tumor volume, relative tumor growth rate, tumor volume anti-tumor rate and other indicators were calculated. The tumor volume formula was TV=0.5a×b 2 where a is the longest diameter of the tumor and b is the shortest diameter of the tumor.

[0183] The experimental results are shown in Table 6 below. As can be seen from the experimental results, the test samples CR194Q1, CR194V5, CR194AH, CR194X3, CR194U9, CR194Z9, CR194AB, CR194AX, CR194AY and CR194AR all had good inhibitory effects on the mouse CFPAC-1 CDX tumor model. [Table 12] Example 7 Conjugate Compound HuPrime (R) Antitumor experiments on xenograft PDX models

[0184] Experimental objective: To study the efficacy of the conjugate compounds CR194Q1, CR194X3, CR194AX, CR194AR and CR194AY in OV2423 PDX models.

[0185] Model: ovarian cancer animal model OV2423 from China Crown and Crown Biotechnology (Taicang) Co., Ltd.

[0186] Experimental method: The prepared tumor tissue mass was subcutaneously inoculated into the right anterior limb of BALB / c-nude mice until the tumor volume reached 80-160 mm. 3 When the tumor was amplified, the mice were randomly divided into groups, and model control groups and treatment groups were set up. Treatment began on the first day of grouping, and the dosage was adjusted according to the latest body weight of the mice, and the tail vein was injected, with a volume of 10μl / g. After group administration, monitoring included tumor growth and the effects of treatment on the normal behavior of the animals, including the activity of the experimental animals, feeding and drinking status, weight gain or loss, eyes, hair and other abnormal conditions. After group administration, the mice were weighed twice a week, and the weight change rate was calculated. At the same time, the long and short diameters of the tumors were measured with calipers, and the tumor volume, relative tumor growth rate and tumor volume anti-tumor rate were calculated. The tumor volume formula is TV=0.5a×b 2 where a is the longest diameter of the tumor and b is the shortest diameter of the tumor.

[0187] The experimental results are shown in Table 7 below. As can be seen from the experimental results, the test samples CR194Q1, CR194X3, CR194AX, CR194AR and CR194AY showed excellent anti-tumor growth effects in the FOLR1 monoclonal antibody model OV2423. [Table 13] Example 8 Safety evaluation of conjugate compounds in MIAPaca-2 human pancreatic cancer model BALB / c nude mice

[0188] Objective: To test the effect of the conjugate compounds on the toxicity of subcutaneously xenografted MIAPaCa-2 human pancreatic cancer cells in nude mice model under the same dose conditions.

[0189] Sample preparation: Weigh out an appropriate amount of compound, dissolve it in PBS, add an appropriate amount of alkaline solution to prepare a sample mother solution with neutral pH, filter, and dilute the mother solution with filtered saline to a working concentration sample solution, and reserve.

[0190] Experimental method: The prepared tumor tissue mass was subcutaneously inoculated into the right anterior limb of BALB / c-nude mice until the tumor volume reached 80-160 mm. 3 When the tumors were amplified, they were randomly divided into groups, and model control groups and treatment groups were set up. Treatment began on the first day of grouping, and the dosage was adjusted according to the latest body weight of the mice, and the tail vein was injected, with a volume of 10 μl / g. After group administration, monitoring included tumor growth and the effects of treatment on the normal behavior of the animals, including the activity of the experimental animals, feeding and drinking status, weight gain or loss, eyes, hair and other abnormal conditions. After group administration, the mice were weighed twice a week to calculate the weight change rate, and the major and minor diameters of the tumors were measured twice a week with calipers, and the tumor volume, relative tumor growth rate and tumor volume anti-tumor rate and other indicators were calculated. The tumor volume formula is TV=0.5a×b 2 where a is the long diameter of the tumor and b is the short diameter of the tumor. The experimental design is as shown in Table 8 below. [Table 14]

[0191] As shown in Figure 1A-1B, CR194L4 (100mg / kg iv q3d*6) and CR194A6 (100mg / kg iv q3d*3) had good MIAPaCa-2 antitumor effects. After the first administration of CR194L4 (100mg / kg iv q3d*6), the body weight of all groups gradually decreased, but after the fourth administration, the administration was stopped and the body weight of the animals gradually increased. For CR194A6 (100mg / kg iv q3d*3), one experimental animal died on the experimental day d2, and the body weight of the experimental animals in the same group gradually increased, and the body weight of the experimental animals in the remaining groups gradually fluctuated, but the overall tendency was increasing. Example 9 Safety evaluation of conjugate compound CR194AX in ICR mice

[0192] Purpose of the experiment: To evaluate the safety of CR194AX in ICR mice

[0193] Sample preparation: Weigh out an appropriate amount of CR194AX, dissolve it in PBS, add an appropriate amount of alkaline solution to prepare a sample mother solution with a neutral pH, filter it, and dilute the mother solution with filtered PBS to a working concentration sample solution, and reserve it.

[0194] Experimental design: ICR mice (female, 6-8 weeks old, weighing about 25g) were randomly divided into groups according to body weight, and administration began on the first day of grouping. The dosage was adjusted according to the mouse's most recent body weight, and was injected via the tail vein, with an administration volume of 10μl / g. After group administration, the effects of the drug on the normal behavior of the animals were detected, including the activity of the experimental animals, feeding and drinking status, body weight, eyes, fur, feces, secretions and other abnormal conditions. The mice were weighed twice a week and observed for 8 days after the last administration. At the end of the experiment, the liver and spleen were weighed, and the liver, spleen, lungs, kidneys and stomach were taken and placed in 10% formalin neutral fixative for HE analysis. Sample preparation: An appropriate amount of compound was weighed, dissolved in PBS, and an appropriate amount of alkaline solution was added to prepare a sample mother solution with a neutral pH, filtered, and the mother solution was diluted with filtered saline to a working concentration sample solution and prepared.

[0195] Experimental results and analysis: CR194AX 50mg / kg was administered once a week for three times (qw*3) and once every three days for six times (q3d*6). During the administration period, no mice died and the average weight loss of the mice did not exceed 10%, showing good tolerance. During the administration period of CR194AX 25mg / kg q3d*6, no mice died and the average weight loss of the mice did not exceed 5%, showing good tolerance (see Figure 2A-2B). At the end of the experiment, liver and spleen were taken and the results: There was no significant difference in liver and spleen weights of mice in each administration group compared to the negative control group. Example 10: Safety evaluation of conjugate compound CR194X3 in BALB / c nude mice

[0196] Purpose of the experiment: Safety evaluation of CR194X3 in BALB / c nude mice

[0197] Sample preparation: Weigh out an appropriate amount of CR194X3, dissolve it in PBS, add an appropriate amount of alkaline solution to prepare a sample mother solution with a neutral pH, filter, and dilute the mother solution with filtered PBS to a working concentration sample solution, and reserve.

[0198] BALB / c nude mice (female, 6-8 weeks old, weighing about 25g) were randomly divided into groups (6 mice per group) according to body weight, and administration began on the first day of grouping. The dosage was adjusted according to the mouse's most recent body weight, and was injected via the tail vein at a volume of 10μl / g. After administration in each group, the effects of the drug on the normal behavior of the animals were detected, including the activity of the experimental animals, feeding and drinking status, body weight, eyes, hair, feces, secretions, and other abnormal conditions. The mice were weighed twice a week and observed for 7 days after the last administration. At the end of the experiment, the liver and spleen were weighed, and the lungs, liver, spleen, and small intestine were removed and placed in 10% formalin neutral fixative for HE analysis.

[0199] Experimental results and analysis: Mice tolerated the test substance CR194X3 (150mg / kg) well. Livers and spleens were taken at the end of the experiment. There was no significant difference in liver and spleen weights between the mice in each administration group compared to the negative control group. Example 11 Safety evaluation of CR194AX and CR194X3 in SD rats

[0200] Experimental objective: Safety evaluation of CR194-based compounds in SD rats

[0201] Sample preparation: Weigh out an appropriate amount of compound, dissolve it in saline, add an appropriate amount of alkaline solution to prepare a sample mother solution with a neutral pH, filter, and dilute the mother solution with filtered saline to a working concentration sample solution, and reserve.

[0202] Experimental method: SD rats (female, weighing 160-180g) were randomly divided into groups (5 rats per group) according to body weight, and the administration started on the first day of grouping. The administration amount was adjusted based on the rat's most recent body weight, and the administration volume was 10ml / kg by tail vein injection. After group administration, the effects of the drug on the normal behavior of the animals were detected, including the activity, feeding and drinking status, body weight, eyes, hair, feces, secretions and other abnormal conditions of the experimental animals. The rats were weighed twice a week and observed for 14 days after administration.

[0203] Experimental results and analysis: The body weight of the animals in each treatment group decreased continuously from the day of treatment until the third day, but did not exceed 10%. There were no abnormal clinical findings (Figures 3A-3B).

Claims

1. A conjugate compound having the following structure or a pharmaceutically acceptable salt thereof, Multi-ligand moiety-(linker-payload) ｑ , wherein, the multi-ligand moiety contains at least two ligands targeting different cell surface molecules, the linker-payload moiety has the following structure, 【Chemical 1】 wherein, R is [Chemical 2] selected from R １ is each independently a bond or -CH ２ CH ２ C(O)-NH- and is selected from R ２ is each independently hydrogen and 【Chemical 3】 selected from R ３ are each independently hydrogen and 【Chemical 4】 selected from R ４ is each independently hydrogen and 【Chemical Formula 5】 selected from R ５ is independently bonded to, -(CH ２ CH ２ O) ３ -CH ２ CH ２ -, -CH ２ C(O)-NH-CH ２ -, -CH ２ C(O)-, -CH ２ C(O)-NH-CH ２ C(O)- and [Chemical Formula 6] selected from R ６ are each independently bonded 【Chemical Formula 7】 selected from X is independently selected from a bond, C and O, m is independently 0 or 1, n is independently 0 or 1, p is 0 or 1, q is an integer from 1 to 4, D is a payload, the conjugate compound or a pharmaceutically acceptable salt thereof.

2. A conjugate compound having the following structure or a pharmaceutically acceptable salt thereof, Multi-ligand moiety-(linker-payload) ｑ , wherein, the multi-ligand moiety contains at least two ligands targeting different cell surface molecules, the linker-payload moiety has the following structure, 【Chemical Formula 8】 wherein, R is 【Chemical Formula 9】 selected from R １ is independently selected from a bond and -CH ２ CH ２ C(O)-NH-, R ２ are each independently hydrogen and 【Chemical 10】 selected from R ３ each independently represents hydrogen and 【Chemical 11】 selected from R ４ are each independently hydrogen and 【Chemical 12】 selected from R ５ is independently bonded to, -(CH ２ CH ２ O) ３ -CH ２ CH ２ -, -CH ２ C(O)-NH-CH ２ -, -CH ２ C(O)-, -CH ２ C(O)-NH-CH ２ C(O)- and 【Chemical 13】 selected from m is independently 0 or 1, n is independently 0 or 1, p is 0 or 1, q is an integer from 1 to 4, D is a payload, the conjugate compound according to Claim 1 or a pharmaceutically acceptable salt thereof.

3. A conjugate compound having the following structure or a pharmaceutically acceptable salt thereof, Multi-ligand moiety-(linker-payload) ｑ , wherein, the multi-ligand moiety contains at least two ligands targeting different cell surface molecules, the linker-payload moiety has the following structure, 【Chemical Formula 14】 wherein, R １ is independently selected from a bond and -CH ２ CH ２ C(O)-NH-, R ２ are each independently hydrogen and 【Chemical Formula 15】 selected from R ５ is independently bonded to, - (CH ２ CH ２ O) ３ -CH ２ CH ２ -, -CH ２ C(O)-NH-CH ２ -, -CH ２ C(O)-, -CH ２ C(O)-NH-CH ２ C(O)- and 【Chemical 16】 selected from R ６ are each independently bonded 【Chemical 17】 selected from X is independently selected from a bond, C and O, n is independently 0 or 1, q is an integer from 1 to 4, D is a payload, the conjugate compound according to Claim 1 or a pharmaceutically acceptable salt thereof.

4. A conjugate compound having the following structure or a pharmaceutically acceptable salt thereof, Multi-ligand moiety—(linker—payload) ｑ , wherein, the multi-ligand moiety contains at least two ligands targeting different cell surface molecules, the linker-payload moiety has the following structure, 【Chemical 18】 wherein, R １ is each independently a bond or -CH ２ CH ２ C(O)-NH- and is selected from, R ３ each independently represents hydrogen or -R １ -R-NH-R ５ -D, and is selected from R ４ is hydrogen or 【Chemical Formula 19】 is R is 【Chemical 20】 selected from R ５ is independently selected from a bond, -(CH ２ CH ２ O)- ３ -CH ２ CH ２ -, -CH ２ C(O)-NH-CH ２ -, -CH ２ C(O)-NH-CH ２ C(O)- and -CH ２ C(O)-, and is selected from: R ６ are each independently bonded 【Chemical 21】 selected from X is independently selected from a bond, C and O, m is independently 0 or 1, q is an integer from 1 to 4, D is the conjugate compound according to claim 1, which is a payload, or a pharmaceutically acceptable salt thereof.

5. A conjugate compound having the following structure or a pharmaceutically acceptable salt thereof, Multi-ligand moiety-(linker-payload) ｑ , where the multiligand moiety contains at least two ligands targeting different cell surface molecules, the linker-payload moiety has the following structure, 【Chemical 22】 where R １ is independently selected from a bond and -CH ２ CH ２ C(O)-NH-, R ３ each independently represents hydrogen or -R １ -R-NH-R ５ -D, and is selected from R ４ is hydrogen or 【Chemical 23】 and R is 【Chemical 24】 and R ５ is independently bonded to, - (CH ２ CH ２ O) ３ -CH ２ CH ２ -, -CH ２ C(O)-NH-CH ２ -, -CH ２ C(O)-NH-CH ２ C(O)-, -CH ２ C(O)- and 【Chemical 25】 is selected from R ６ are each independently bonded, 【Chemical 26】 is selected from X is independently selected from a bond, C and O respectively, m is independently 0 or 1 respectively, q is an integer from 1 to 4, D is the conjugate compound according to claim 1, which is a payload, or a pharmaceutically acceptable salt thereof.

6. R ５ is not -CH ２ C(O)-NH-CH ２ The conjugate compound according to any one of claims 1 to 5 or a pharmaceutically acceptable salt thereof, which is not.

7. The conjugate compound or a pharmaceutically acceptable salt thereof is as follows (a) m is independently 0 or 1 respectively, and n is 0; (b) m is 0, and n is independently 0 or 1 respectively; (c) m is 0, and n is 0; (d) m is 0, n is 0, and R5 is not -CH2C(O)-NH-CH2-, The conjugate compound or a pharmaceutically acceptable salt thereof according to any one of claims 1 to 6, comprising one or more features selected from the group consisting of

8. R ６ is 【Chemical 27】 The conjugate compound or a pharmaceutically acceptable salt thereof according to any one of claims 1 or 3 to 7.

9. X is a bond or O, the conjugate compound or a pharmaceutically acceptable salt thereof according to claim 8.

10. The conjugate compound or a pharmaceutically acceptable salt thereof is as follows (a) R ６ is 【Chemical Formula 28】 and X is a bond; (b) R6 is 【Chemical 29】 and X is O; (c) R6 is 【Chemical Formula 30】 and X is a bond; (d) R6 is 【Chemical 31】 X is O; (e) R6 is 【Chemical 32】 X is a bond; and (f) R6 is 【Chemical 33】 X is O, The conjugate compound or a pharmaceutically acceptable salt thereof according to claim 1, or any one of claims 3 to 9, comprising one or more features selected from the group consisting of

11. The linker of the conjugate compound or a pharmaceutically acceptable salt thereof according to any one of claims 1 to 5 has a structure selected from the following group. 【Table 1】

12. The payload is selected from the group consisting of the following: small molecule compounds, nucleotides, and peptides, and preferably, the payload is a small molecule compound. The conjugate compound or a pharmaceutically acceptable salt thereof according to any one of claims 1 to 11.

13. D is each independently 【Chemical 34】 selected from. The conjugate compound or a pharmaceutically acceptable salt thereof according to any one of claims 1 to 12.

14. The cell surface molecule is independently selected from TRPV6, FOLR1, PSMA, and SSTR2. The conjugate compound or a pharmaceutically acceptable salt thereof according to any one of claims 1 to 13.

15. The cell surface molecules are TRPV6 and FOLR1, PSMA and FOLR1, or SSTR2 and FOLR1, respectively. The conjugate compound or a pharmaceutically acceptable salt thereof according to any one of claims 1 to 14.

16. The ligand targeting FOLR1 is selected from folic acid or an analog thereof, and preferably, the folic acid analog is selected from 5-methyltetrahydrofolic acid, 5-formyltetrahydrofolic acid, methotrexate, and 5,10-methylenetetrahydrofolic acid. Here, the ligand targeting SSTR2 is selected from octreotide and any analog thereof. The conjugate compound or a pharmaceutically acceptable salt thereof according to claim 14 or 15.

17. The ligand moiety has the following structure. The conjugate compound or a pharmaceutically acceptable salt thereof according to any one of claims 1 to 16. 【Table 2】

18. A conjugate compound selected from the following or a pharmaceutically acceptable salt thereof. 【Table 3】

19. A pharmaceutical composition comprising the conjugate compound or a pharmaceutically acceptable salt thereof according to any one of claims 1 to 18, and a pharmaceutically acceptable vector.

20. For use in delivering a payload to a subject in need thereof, the conjugate compound or a pharmaceutically acceptable salt thereof according to any one of claims 1 to 18, or the pharmaceutical composition according to claim 19, comprising administering to the subject a therapeutically effective amount of the conjugate compound or a pharmaceutically acceptable salt thereof according to any one of claims 1 to 18, or the pharmaceutical composition according to claim 19. The conjugate compound or a pharmaceutically acceptable salt thereof, or the pharmaceutical composition.

21. The conjugate compound according to any one of claims 1 to 18 or a pharmaceutically acceptable salt thereof, or the pharmaceutical composition according to claim 19, for use in treating a disease in a subject, comprising administering to the subject a therapeutically effective amount of the conjugate compound according to any one of claims 1 to 18 or a pharmaceutically acceptable salt thereof, or the pharmaceutical composition according to claim 19, Optionally, the disease is selected from the group consisting of the following groups: cancer, immune diseases, metabolic diseases and neurological diseases, Optionally here, i) the cancer is selected from the group consisting of the following groups: pancreatic cancer, biliary tract cancer, liver cancer, breast cancer, thyroid cancer, colorectal cancer, esophageal cancer, lung cancer, kidney cancer, leukemia, ovarian cancer, gastric cancer, uterine cancer, endometrial cancer, colon cancer, testicular cancer, skin cancer, prostate cancer, lymphoma and multiple myeloma; ii) the immune disease is an autoimmune disease, preferably, the autoimmune disease is selected from the group consisting of the following groups: connective tissue disease, systemic sclerosis, rheumatoid arthritis and systemic lupus erythematosus; iii) the metabolic disease is selected from the group consisting of the following groups: diabetes, gout, obesity, hypoglycemia, hyperglycemia and dyslipidemia; or iv) the neurological disease is selected from the group consisting of the following groups: Alzheimer's disease, Parkinson's disease, Huntington's disease, head injury, multiple sclerosis, dizziness, coma and epilepsy, the conjugate compound or a pharmaceutically acceptable salt thereof, or the pharmaceutical composition.

22. The conjugate compound according to claim 21 or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition, for use, further comprising administering in combination one or more therapeutic agents with the conjugate compound or a pharmaceutically acceptable salt thereof, or the pharmaceutical composition.

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