Dual-payload antibody-drug conjugate and use thereof

Abstract

The present disclosure relates to a dual-payload antibody-drug conjugate (ADC), a composition containing the ADC molecule, and therapeutic use thereof.

Description

Dual-load antibody drug conjugates and uses thereof

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411238980.9, filed on September 4, 2024, Chinese Patent Application No. 202510713046.6, filed on May 29, 2025, and Chinese Patent Application No. 202511223974.0, filed on August 29, 2025. TECHNICAL FIELD

[0003] The present disclosure relates to dual-load ligand conjugated drugs, more specifically to ligand conjugated drugs comprising a bifunctional cyclic dinucleotide (CDN) STING agonist and one or more additional payloads, compositions comprising them, and their use in the treatment or prevention of diseases. BACKGROUND

[0004] The cGAS-STING signaling pathway is an important mechanism of cytosolic DNA sensing, which plays a key role in regulating pathogen infection, tumor immunity and autoimmune diseases. When cGAS detects dsDNA of various origins such as viral, bacterial DNA, mitochondrial DNA, etc., it catalyzes the synthesis of cGAMP (cyclic dinucleotide 2'3'-cyclic AMP-GMP), activates STING, and then regulates the expression of type I IFN (interferon) and the expression of genes driven by NF-κB transforming factor (inflammatory gene expression, including cytokines and chemokines), which can limit viral replication and induce apoptosis, thereby regulating pathogen infection, tumor immunity, etc.

[0005] Given that endogenous cGAMP is a key mediator of the innate immune system’s response to tumors, ultimately contributing to interferon or proinflammatory cytokine production and thereby enabling therapeutic benefit, a series of CDN-type STING agonists have been developed for antiviral or cancer immunotherapy, but clinical development has faced challenges, including: easy to be destroyed by ENPP1 and ENPP3 phosphatase hydrolases in vivo, losing activity, short half-life in the circulatory system, low bioavailability, and relying on intratumoral administration in clinical use; if injected in other ways, they can induce a systemic cytokine response; even with intratumoral administration, its convenience and patient acceptability are limited; in addition, the short exposure of such compounds to immune cells in the tumor environment also reduces their effect.

[0006] The bifunctional CDN STING agonist developed by the present inventors (WO2022083584, the entire contents of which are incorporated herein) first integrates a cytotoxic molecule into the CDN STING agonist structure. The resulting bifunctional CDN compound first activates the STING innate immune pathway after entering the body, killing tumor cells, and releasing cytotoxic substructure units after drug decomposition, further killing tumor cells, increasing the antigen presentation activity of innate immune cells to provide tumor marker fragments for the adaptive immune system, providing the body with immune memory, and consolidating long-term immune tumor suppression effect. Studies have shown that the bifunctional CDN STING agonist exhibits more effective inhibition of tumor cell proliferation than the pure STING agonist marker compound ADU-S100 in multiple tumor cell lines, and also exhibits significantly superior tumor inhibition effect than ADU-S100 in in vivo tumor pharmacological models (CT26, 4T1, A20, B16F10, H22, etc.). However, there are still the common problems of CDN immune agonist drugs described above, including easy enzymatic degradation, short half-life, and limitation to intratumoral administration, which limits their use as systemic immunotherapy.

[0007] Ligand-targeted conjugate drugs, especially antibody-targeted conjugate drugs (ADCs), are a new technology for efficient and low-toxic drug delivery, which can solve the application defects of CDN STING agonists to some extent. However, ADCs also have many challenges, such as uncontrolled release or insufficient release of the payload, off-target toxicity, easy aggregation, resulting in some defects such as short half-life, fast clearance, immunogenicity, complexity of pharmacokinetics, and drug resistance. In practice, it is far from easy to develop a specific cytotoxic molecule into an ideal ligand conjugate drug such as an ADC drug that remains stable in the blood circulation, precisely reaches the treatment target, and finally releases the cytotoxic payload inside or near the target (e.g., cancer cells), with high efficacy and low toxicity.

[0008] Therefore, there is an urgent need for a new therapy that can precisely deliver CDN STING agonists to the tumor environment, replace intratumoral administration with a more friendly administration method, prolong and improve drug efficacy, and reduce toxic side effects. Moreover, given the long-standing demand for safe and effective therapeutic drugs in the field of tumor treatment, other drug design strategies are needed to further enhance the efficacy and safety of STING agonists.

[0009] SUMMARY

[0010] To meet the above needs in the art, the inventors have conducted in-depth research, adopted the mechanism of the ADC drug delivery system based on the STING agonist, further adopted the idea of intramolecular drug combination, coupled the previously developed bifunctional CDN STING agonist with other payload drugs and specific targeting molecules through a linker unit, thereby fusing them in a single ADC molecule, to obtain a dual-load bifunctional cyclic dinucleotide conjugate drug as shown herein.

[0011] The conjugate drug targets immune activation and cytotoxic molecules with different mechanisms of action to the same cell, and the synergistic effect of the two mechanisms achieves safe and efficient treatment, solving the above needs. The obtained dual-load conjugate has good physical properties, no obvious antibody aggregation phenomenon, and can be quickly and effectively endocytosed by tumor cells; in animal models, it not only exhibits significantly improved tumor growth inhibition activity and good tolerance compared to CDN STING agonists and single-load bifunctional CDN STING ADCs, but also shows a synergistic tumor inhibition effect beyond the sum of single-load bifunctional CDN STING ADCs and single-load other payload ADCs. Therefore, the dual-load ADC of the present disclosure is expected to be able to replace intratumoral administration with more traditional, mature and friendly administration methods (such as intravenous, subcutaneous, intramuscular, external application, etc.), expand the indications and benefit population, and provide efficient and safe treatment.

[0012] Therefore, in a first aspect, the present disclosure provides a ligand-drug conjugate having the following formula (X) or a pharmaceutically acceptable salt, ester, isomer, solvate, prodrug or isotopically labeled thereof:

[0013] wherein,

[0014] Q represents a targeting ligand;

[0015] D1 represents a first payload, which is a cyclic dinucleotide as defined herein (a compound of formula (II), (II-a), (II-a'), (II-b), (II-b'));

[0016] D2 represents a second payload as defined herein below;

[0017] L represents a linker unit connecting D1 and D2 to Ab;

[0018] q represents the number of , connected to Q, for example q is an integer or non-integer from about 1 to 20, for example 2-18, 4-16, 5-12, 1-10, 1-8, 2-8, 3-8, 2-6, 4-6, 4-8, 6-8, 6-10.

[0019] In the ligand drug conjugates of the present disclosure, the targeting ligand is selected from the group consisting of an antibody or antigen binding fragment, a peptide ligand, and any other molecule capable of targeting cancer cells.

[0020] In some embodiments, the targeting ligand in the ligand drug conjugates of the present disclosure is an antibody or antigen binding fragment, formula X can be represented as

[0021] In some embodiments, the targeting ligand in the ligand drug conjugates of the present disclosure is a peptide ligand.

[0022] The following description of the ligand-drug conjugates of the present disclosure is exemplified with an antibody or antigen binding fragment, but it is understood that the antibody or antigen binding fragment therein can be replaced by a peptide ligand or any other molecule capable of targeting cancer cells.

[0023] In a second aspect, the present disclosure provides a pharmaceutical composition comprising the ADC of the present disclosure or a pharmaceutically acceptable salt, ester, isomer, solvate, prodrug or isotopically-labeled form thereof, optionally at least one other therapeutic agent, and optionally one or more pharmaceutically acceptable excipients.

[0024] In a third aspect, the present disclosure provides the ADC of the present disclosure or a pharmaceutically acceptable salt, ester, isomer, solvate, prodrug or isotopically-labeled form thereof or a pharmaceutical composition comprising the same for use as a therapeutic agent for the treatment or prevention of a disease, in particular for the treatment or prevention of a STING-related or mediated disease, more particularly for the treatment or prevention of an inflammatory, allergic or autoimmune disease, an infectious disease or a hyperproliferative disease, especially as an anti-tumor or anti-viral therapeutic agent, or as a vaccine adjuvant; in particular, as a cytotoxic agent for the treatment or prevention of a hyperproliferative disease, especially a tumor, or as a cytotoxic agent for the treatment or prevention of a viral infection.

[0025] In a fourth aspect, the present disclosure provides the use of the ADC of the present disclosure or a pharmaceutically acceptable salt, ester, isomer, solvate, prodrug or isotopically-labeled form thereof or a pharmaceutical composition comprising the same for the prevention or treatment of a disease, in particular a STING-related or mediated disease, more particularly an inflammatory, allergic or autoimmune disease, an infectious disease or a hyperproliferative disease, especially a tumor or a viral infection.

[0026] In a fifth aspect, the present disclosure provides the ADC of the present disclosure or a pharmaceutically acceptable salt, ester, isomer, solvate, prodrug or isotope-labeled thereof or a pharmaceutical composition comprising the same for use as a multifunctional active agent, which possesses both immunotherapeutic and cytotoxic therapeutic activities, including the ability to activate the immune system to exert anti-tumor and anti-viral replication functions by agonizing the STING signaling pathway, to cause tumor cell death or to stop viral replication by releasing at least two cytotoxic agents, to continuously activate STING to kill tumor cells by releasing tumor DNA in turn, and to provide “immunological memory” or durable immunity to the tumor by releasing tumor neoantigens to generate antibody-antigen responses. In this aspect, the present disclosure also provides the use of the ADC of the present disclosure or a pharmaceutically acceptable salt, ester, isomer, solvate, prodrug or isotope-labeled thereof or a pharmaceutical composition comprising the same for achieving the above-mentioned multiple functions.

[0027] In a sixth aspect, the present disclosure provides a method of treating or preventing a disease, in particular a disease associated with or mediated by STING, more particularly an inflammatory, allergic or autoimmune disease, an infectious disease or a hyperproliferative disease, especially a tumor or a viral infection, in a subject, the method comprising administering to the human or animal the ADC of the present disclosure or a pharmaceutically acceptable salt, ester, isomer, solvate, prodrug or isotope-labeled thereof or a pharmaceutical composition comprising the same. In particular, the present disclosure provides a method of treating or preventing a hyperproliferative disease, especially a tumor, in a subject, or a method of treating or preventing a viral infection in a subject, the method comprising administering to the human or animal the ADC of the present disclosure or a pharmaceutically acceptable salt, ester, isomer, solvate, prodrug or isotope-labeled thereof or a pharmaceutical composition comprising the same.

[0028] In a seventh aspect, the present disclosure provides the use of the ADC of the present disclosure or a pharmaceutically acceptable salt, ester, isomer, solvate, prodrug or isotope-labeled thereof or a pharmaceutical composition comprising the same in the manufacture of a medicament for preventing or treating a disease, in particular a disease associated with or mediated by STING, more particularly an inflammatory, allergic or autoimmune disease, an infectious disease or a hyperproliferative disease, especially a tumor or a viral infection. In particular, the present disclosure provides the use of the ADC of the present disclosure or a pharmaceutically acceptable salt, ester, isomer, solvate, prodrug or isotope-labeled thereof or a pharmaceutical composition comprising the same in the manufacture of a medicament for treating or preventing a hyperproliferative disease, especially a tumor, and the use of the ADC of the present disclosure or a pharmaceutically acceptable salt, ester, isomer, solvate, prodrug or isotope-labeled thereof or a pharmaceutical composition comprising the same in the manufacture of a medicament for treating or preventing a viral infection.

[0029] In an eighth aspect, the present disclosure provides a pharmaceutical combination comprising an ADC of the present disclosure or a pharmaceutically acceptable salt, ester, isomer, solvate, prodrug, or isotopically-labeled form thereof, and at least one other therapeutic agent; for use in the prevention or treatment of a disease, in particular a disease associated with or mediated by STING, more particularly an inflammatory, allergic or autoimmune disease, an infectious disease or a hyperproliferative disease, especially a tumor or viral infection; and a method of treating or preventing a disease, in particular a disease associated with or mediated by STING, more particularly an inflammatory, allergic or autoimmune disease, an infectious disease or a hyperproliferative disease, especially a tumor or viral infection, in a subject, comprising administering to the human or animal a pharmaceutical combination of the present disclosure.

[0030] In a ninth aspect, the present disclosure also provides a method of making an ADC of the present disclosure or a pharmaceutically acceptable salt or solvate thereof, by conjugating a CDN as defined herein (e.g., a compound of formula (II), (II-a), (II-a’), (II-b), (II-b’)) and a second payload to an antibody or antigen-binding fragment thereof via a linker unit.

[0031] The following drawings and specific embodiments further illustrate the present application. These drawings and specific embodiments, however, are not to be taken as limiting the present application and changes readily suggested by persons of ordinary skill in the art are to be included within the spirit and scope of the present application and the appended claims. BRIEF DESCRIPTION OF DRAWINGS

[0032] FIG. 1A shows the in vivo tumor inhibition effect of bifunctional CDN intratumoral administration in a mouse CT26 cell transplantation model (dosing tumor).

[0033] FIG. 1B shows the in vivo tumor inhibition effect of bifunctional CDN intratumoral administration in a mouse CT26 cell transplantation model (non-dosing tumor).

[0034] FIG. 2 shows the in vivo tumor inhibition effect of dual-loading CDN-ADC of the present disclosure in a mouse EMT6-hHer2 cell transplantation model.

[0035] FIG. 3 shows the in vivo tumor inhibition effect of dual-loading CDN-ADC of the present disclosure in a mouse GP2D cell transplantation model.

[0036] FIG. 4 shows the in vivo tumor inhibition effect of dual-loading CDN-ADC of the present disclosure in a mouse AsPC1 cell transplantation model.

[0037] FIG. 5 shows the in vivo tumor inhibition effect of dual-loading CDN-ADC of the present disclosure in a mouse SK-OV-3 cell transplantation model.

[0038] Figure 6 shows a schematic of the bifunctional cyclodin effective payload 1 and payload 2 association with an antibody via a key intermediate PL in a dual payload ADC of the disclosure.

[0039] DETAILED DESCRIPTION

[0040] DEFINITIONS

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. For purposes of the present disclosure, the following terms are defined below.

[0042] When a trade name is used herein, unless otherwise indicated, the trade name includes the product formulation, generic drug, and active pharmaceutical ingredient of the trade name product, unless otherwise indicated by context.

[0043] As used herein, the term "about," in reference to a value or parameter, means that the value or parameter is floating within ±10% of the indicated value or parameter, e.g., floating within ±5%, ±2%, or ±1% of the indicated value or parameter.

[0044] As used herein, the term "substantially" means a majority of, that is, > 50% of the population, mixture, or sample, preferably greater than 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99%.

[0045] As used herein, the term "and / or" is understood to mean either one of the items or any combination of the items in the alternative.

[0046] As used herein, the term "comprising" or "including," or "having" means including, but not limited to, the stated elements, integers or steps. As used herein, the term "comprising" or "including," or "having" also contemplates embodiments consisting essentially of, or consisting of the stated elements, integers or steps, unless otherwise indicated by context. For example, when referring to an antibody variable region "comprising" a particular sequence, an antibody variable region consisting of the particular sequence is also contemplated.

[0047] As used herein, the term "immune system" has its generally accepted meaning to one of ordinary skill in the art, and means the whole or any one or more components of molecules, substances (such as body fluids), anatomical structures (such as cells, tissues, or organs), and physiological processes related to preventing infection in the body, protecting the body during infection or disease, and / or helping the body recover from infection or disease.

[0048] As used herein, the term "ADC" refers to an antibody-drug conjugate.

[0049] In the present context, the term "drug" or "payload" refers to one or more substances administered to a human or animal to obtain some therapeutic effect, including substances that prevent, cure or alleviate the effects of a disease, improve health conditions. In the present disclosure, the "drug" or "payload" is selected from the group consisting of small molecule compounds, nucleotides, peptides and proteins, in particular from small molecule compounds or nucleotides.

[0050] In some embodiments, the payload of the present disclosure includes, but is not limited to, anticancer drugs, radioactive substances, vitamins, anti-AIDS drugs, antibiotics, immunosuppressants, antiviral drugs, enzyme inhibitors, neurotoxins, opioids, cell-extracellular matrix interaction modulators, vasodilators, antihypertensives, hypnotics, antihistamines, anticonvulsants, muscle relaxants, antiparkinson drugs, antispastic and muscle contractant drugs, antiparasitic and antiprotozoal drugs, analgesics, antipyretics, steroidal or non-steroidal anti-inflammatory drugs, anti-angiogenic factors, anti-secretion factors, anticoagulants and anti-thrombotic agents, local anesthetics, prostaglandins, antipsychotics, antiemetics or imaging agents.

[0051] In some embodiments, the payload in the dual payload antibody conjugate drug of the present disclosure has a free amino, hydroxyl or carboxyl group to be linked to the conjugate drug by acylation reaction with the corresponding moiety of the conjugate drug.

[0052] In the present context, the term "small molecule compound" refers to a compound having a molecular weight of less than or equal to about 2 kDa, for example a molecular weight of less than or equal to about 1.5 kDa. In some embodiments, the small molecule compound has a molecular weight of less than or equal to about 1 kDa, 800 Da, 700 Da, 600 Da, 500 Da.

[0053] In the present context, the term "derivative" refers to a compound obtained by substitution of one or more atoms or groups of atoms of a parent compound molecule with other atoms or groups of atoms, which compound has a biological activity comparable to or improved over the parent compound molecule.

[0054] In the present context, the term "STING" is an abbreviation of stimulator of interferon genes. STING is a transmembrane protein receptor in human cells, activation of STING by cyclic dinucleotides (CDNs) leads to activation of the IRF3 and NF-κΒ pathways, thus leading to induction of type I interferons and proinflammatory cytokines, respectively. The term "STING agonist" refers to any substance that activates STING in vitro or in vivo to elicit the corresponding physiological response, in particular a CDN STING agonist as defined herein.

[0055] In the present context, the term "disease associated with or mediated by STING" means a disease which can be alleviated by induction of an immune response via the STING pathway, i.e. a disease in which activation of STING will reduce the incidence of the disease, reduce or eliminate the disease condition, including but not limited to inflammatory, allergic or autoimmune diseases, infectious diseases or cancer, etc. For the present disclosure, the "disease associated with or mediated by STING" is preferably selected from a tumor or cancer.

[0056] In the present context, the term "hyperproliferative disease", "tumor" or "cancer" refers to a physiological condition in a subject characterized by uncontrolled or deregulated cell growth or death, including solid and blood-borne tumors, whether malignant or benign, and all pre-cancerous and cancerous cells and tissues. For the various aspects of the present disclosure, the cancer or tumor includes, but is not limited to, brain cancer, skin cancer, bladder cancer, ovarian cancer, breast cancer, stomach cancer, pancreatic cancer, prostate cancer, colon cancer, blood cancer, lung cancer (small cell lung cancer, non-small cell lung cancer) and bone cancer. Examples of the above cancer types include neuroblastoma, intestinal cancer such as rectal cancer, colon cancer, colorectal cancer, familial adenomatous polyposis cancer and hereditary non-lymphomatous colorectal cancer, esophageal cancer, lip cancer, laryngeal cancer, nasopharyngeal cancer, pharyngeal squamous cancer, oral cavity cancer, head and neck cancer, salivary gland cancer, peritoneal cancer, soft tissue sarcoma, urothelial cancer, sweat gland carcinoma, gastric cancer, adenocarcinoma, medullary thyroid carcinoma, papillary thyroid carcinoma, kidney cancer, renal parenchymal carcinoma, ovarian cancer, cervical cancer, uterine body cancer, endometrial cancer, pancreatic cancer, prostate cancer, testicular cancer, breast cancer (including HER2-negative breast cancer), urological cancer, melanoma, brain tumors such as glioblastoma, astrocytoma, meningioma, medulloblastoma and peripheral neuroectodermal tumor, lymphoma such as Hodgkin's lymphoma, non-Hodgkin's lymphoma, Burkitt's lymphoma, acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL), chronic myelogenous leukemia (CLL) and lymphocytic cancer, acute myelogenous leukemia (AML), myelogenous leukemia (chronic myelogenous leukemia (CML), adult T-cell lymphoma, diffuse lymphoma (DLBCL), liver cancer, hepatocellular carcinoma, multiple myeloma, seminoma, osteosarcoma, chondrosarcoma, anal canal cancer, renal cell carcinoma, adrenal cortex cancer, chordoma, fallopian tube cancer, gastrointestinal stromal tumor, myeloproliferative disorders, mesothelioma, biliary tract cancer, Ewing's sarcoma and other rare tumor types, as well as recurrent forms of the above tumors.

[0057] In the present context, the term "anti-tumor effect" refers to a biological effect which can be exhibited by various means, including but not limited to, for example, reduction in tumor volume, reduction in tumor cell number, reduction in tumor cell proliferation or reduction in tumor cell survival.

[0058] In the present context, the term "cytotoxic activity" refers to the cell-killing effect of a drug or conjugated drug or its metabolites. Cytotoxic activity can be expressed as an IC50 value, which is the concentration of drug per unit volume (moles or mass) that results in half of the cells surviving.

[0059] In the present context, the term "cytotoxic agent" or similar expressions refers to an active agent that has cytotoxic activity and causes cell destruction, used against the abnormal and uncontrolled development of cells. The cytotoxic agents involved in the antibody conjugated drugs of the present disclosure are the bifunctional CDN STING agonists as defined herein and the second payload, also including the substances with cytotoxic activity released in vivo thereof.

[0060] The term "multifunctional active agent" as used herein refers to the payload carried by the conjugated drugs of the present disclosure, which, based on its unique structural design, is capable of exerting multiple functions in the body of a subject, combining immunotherapeutic activity and multiple cytotoxic therapeutic activity, including but not limited to the activation of the immune system through the agonism of the STING signaling pathway to exert anti-tumor and anti-viral replication functions, the synergistic killing of tumor cells or the prevention of viral replication through the release of multiple cytotoxic agents, the continuous activation of STING through the release of tumor DNA to kill tumor cells, the release of tumor neoantigens to provide the ability to generate antibody-antigen responses to provide "immunological memory" or durable immunity to the tumor.

[0061] In the present context, the terms "inhibit" and "reduce" or any variation of these terms refer to the ability of a biological active agent to reduce the signaling activity of a target of interest by directly or indirectly interacting with the target, and to any measurable decrease or complete inhibition of the activity of the target of interest. For example, the activity can be reduced by about, at most about, or at least about 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99% or more, or any range derivable therein, as compared to a normal situation.

[0062] In the present context, the term "antigen" refers to an entity that specifically binds to an antibody.

[0063] In the present context, the term "antibody" refers to a polypeptide comprising at least a light chain or a heavy chain immunoglobulin variable region that specifically recognizes and binds to an antigen. The term encompasses various antibody structures, including, but not limited to, monoclonal antibodies, polyclonal antibodies, single-chain antibodies or multiple-chain antibodies, monospecific or multispecific antibodies (e.g., bispecific antibodies), chimeric antibodies or humanized antibodies, full-length antibodies and antibody fragments, as long as they exhibit the desired antigen-binding activity. The antibody can be of any class (e.g., IgG, IgE, IgM, IgD and IgA), type (e.g., IgG1, IgG2, IgG3, IgG4, IgA1 and IgA2) or subtype.

[0064] In the present context, the terms "antibody fragment" and "antigen binding fragment" of an antibody are used interchangeably and refer to a molecule other than the intact antibody that comprises a portion of the intact antibody that is sufficient to confer specific binding of the intact antibody to an antigen to which the intact antibody binds. As will be understood by those in the art, antibody fragments typically comprise amino acid residues from the "complementarity determining regions" or "CDRs" for purposes of antigen binding. Antibody fragments can be made by recombinant DNA techniques, or by enzymatic or chemical cleavage of intact antibodies. Antigen binding fragments include, but are not limited to, Fab, scFab, Fab', F(ab')2, Fab'-SH, Fv, single-chain Fv, diabodies, triabodies, tetrabodies, minibodies, single-domain antibodies (sdAb), heavy-chain antibody fragment VHH; and monospecific, bispecific and multispecific fusion proteins formed from antibody fragments.

[0065] In the present context, reference to an IgG antibody refers to an antibody that is a heterotetrameric protein having an immunoglobulin structure of the IgG class. In an IgG antibody, typically the VHand CH1 of the heavy chain pair with the VL-CL of the light chain to form a Fab fragment that specifically binds to an antigen. Thus, an IgG antibody essentially consists of two Fab molecules connected by an immunoglobulin hinge region and two dimerized Fc regions. In some embodiments, the IgG antibody is, e.g., an IgG1, IgG2, IgG3 or IgG4 antibody. In other embodiments, the IgG antibody is an IgG kappa or IgG lambda antibody, e.g., an IgG1 kappa or IgG1 lambda antibody.

[0066] In the present context, the terms "complementarity determining region" or "CDR region" or "CDR" or "hypervariable region" are used interchangeably and refer to regions in the variable domain of an antibody that are highly variable in sequence and form structurally defined loops ("hypervariable loops") and / or contain antigen contact residues ("antigen contact points"). The CDRs are primarily responsible for binding to an epitope of an antigen. In the present context, the CDRs of the heavy and light chains of an antibody are numbered sequentially starting from the N-terminus, and are generally referred to as CDR1, CDR2 and CDR3. CDRs located within the variable domain of the heavy chain are also referred to as HCDR1, HCDR2 and HCDR3, while CDRs located within the variable domain of the light chain are referred to as LCDR1, LCDR2 and LCDR3. Within a given light chain variable region or heavy chain variable region amino acid sequence, the CDR sequences can be determined using a variety of schemes known in the art, including CDR sequences based on the Kabat, AbM, Chothia, Contact, IMGT definitions. In addition, CDRs can also be determined based on having the same Kabat numbering position as a reference CDR sequence.

[0067] In the present context, the "variable region" or "variable domain" is the domain of the heavy or light chain of an antibody that is involved in binding the antibody to its antigen. The heavy chain variable region (VH) and the light chain variable region (VL) can be further subdivided into regions of hypervariability, termed HVRs, or complementarity determining regions (CDRs), interspersed with regions that are more conserved, termed framework regions (FR). Each VH and VL is composed of three CDRs and four FRs, arranged from amino-terminus to carboxy-terminus in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4. In some aspects, the antibody variable region can be modified by CDR grafting. Since CDR sequences are responsible for most antibody-antigen interactions, recombinant antibody variants can be constructed that mimic the properties of a known antibody. In this antibody variant, the CDR sequences from the known antibody are grafted onto the framework regions of a different antibody with different properties. The properties of the mutated and / or modified antibody or ADC conjugate comprising the same can be assessed in assays, e.g., target antigen binding properties or other desired functional properties, e.g., endocytosis of the ADC, pharmacokinetics, and tumor killing activity in vivo, either in vitro or in vivo.

[0068] In the present context, the term "isotype" refers to the class of antibody as determined by the constant region of the heavy chain. For example, the antibody portion of the ADC according to the present disclosure can be an IgA (e.g., IgAl or IgA2), IgGl, IgG2 (e.g., IgG2a or IgG2b), IgG3, IgG4, IgE, IgM, and IgD antibody, and has the heavy chain constant region of the respective immunoglobulin class. Furthermore, the present disclosure contemplates not only antibodies employing native sequence constant regions, but also antibodies containing variant sequence constant regions.

[0069] In the present context, the term "epitope" includes any protein determinant capable of specific binding to an immunoglobulin or otherwise to a molecule. Epitopic determinants usually consist of chemically active surface groupings of molecules such as amino acids or hydrocarbons or sugar side chains and can have specific three-dimensional structural characteristics, as well as specific charge characteristics. Epitopes can be "linear" or "conformational". The difference between conformational and linear epitopes lies in the loss of binding to the former but not to the latter in the presence of denaturing solvents.

[0070] In the present context, the term "receptor-mediated endocytosis" refers to the process triggered by the binding of a ligand to its corresponding receptor on the cell surface, in which the ligand / receptor complex is internalized and delivered into the cytosol or transferred to an appropriate intracellular compartment. The receptor-mediated endocytosis activity of an antibody can be characterized by determining the rate of endocytosis.

[0071] In the present context, "sequence identity" means the extent to which sequences are identical on a nucleotide-by-nucleotide or amino acid-by-amino acid basis over a window of comparison. Percent sequence identity can be calculated by any of a number of ways known in the art. Optimal alignment can be achieved by any of a number of ways known in the art, for example, using publicly available computer software such as BLAST, BLAST-2, ALIGN or Megalign (DNASTAR) software. Those skilled in the art can determine appropriate parameters for aligning sequences, including any algorithms necessary to achieve the maximum alignment over the full length of the sequences being compared or over a region of interest.

[0072] In the present context, the term "whole antibody" (used herein interchangeably with "full-length antibody", "complete antibody" and "intact antibody") refers to an immunoglobulin molecule comprising at least two heavy chains (H) and two light chains (L). The term "chimeric antibody" refers to an antibody having variable region sequences derived from one species and constant region sequences derived from another species, such as an antibody having variable region sequences derived from a mouse antibody and constant region sequences derived from a human antibody. The term "monoclonal antibody" or "monoclonal antibody composition" refers to a polypeptide, including antibodies, bispecific antibodies, etc., having substantially identical amino acid sequences or derived from the same genetic source, and also includes antibody molecule preparations of a single molecular composition. The term "humanized antibody" refers to an antibody having CDR sequences derived from other mammalian species, such as mouse, grafted onto human framework sequences. The term "human antibody" includes antibodies having variable regions in which both framework and CDR regions are derived from human sequences. The term "recombinant human antibody" includes all human antibodies that are prepared, expressed, created or isolated by recombinant means.

[0073] In the present context, the term "isolated" antibody is an antibody that has been separated from a component of its natural environment. In some embodiments, an antibody is purified to greater than 90%, 95% or 99% purity as determined by, for example, electrophoretic (e.g., SDS-PAGE, isoelectric focusing (IEF), capillary electrophoresis) or chromatographic (e.g., ion exchange or reverse phase HPLC).

[0074] In the present context, the term "affinity" or "binding affinity" refers to the inherent binding affinity of a member of a binding pair to interact with the other member, such as the strength of the interaction of an antibody with an antigen at a single antigenic site, the stronger the interaction the stronger the affinity. The affinity of a molecule for its partner can be represented generally by the equilibrium dissociation constant (K D ), which is the ratio of the dissociation rate constant to the association rate constant (k dis and k on) of the ratio of the dissociation rate constant (Kd, sec"1) to the association rate constant (Ka, M"1sec"1) of the particular antibody-antigen interaction. Affinity can be measured by common methods known in the art, for example, ELISA assays based on antigen protein or cells, flow cytometric assays, bio-layer interferometry (BLI) based technology, and surface plasma resonance technology, among others.

[0075] In the present context, the term "K D " (M) refers to the dissociation equilibrium constant of a particular antibody-antigen interaction, K D dissociation constant (Kd) of the antibody-antigen pair. The measurement of K D dissociation constant (Kd) of the antibody-antigen pair. The measurement of K D dissociation constant (Kd) of the antibody-antigen pair. The measurement of K D dissociation constant (Kd) of the antibody-antigen pair. The measurement of K D dissociation constant (Kd) of the antibody-antigen pair. The measurement of K -1 dissociation constant (Kd) of the antibody-antigen pair. The measurement of K -1 dissociation constant (Kd) of the antibody-antigen pair. The measurement of K -1 dissociation constant (Kd) of the antibody-antigen pair. The measurement of K

[0076] In the present context, the term "binding" or "specific binding" refers to the ability of a single antibody binding site to react with one antigenic determinant. In the context of binding of an antibody to its cognate antigen, binding refers to binding with an affinity having a K -6 dissociation constant (Kd) of the antibody-antigen pair. The measurement of K D dissociation constant (Kd) of the antibody-antigen pair. The measurement of K D dissociation constant (Kd) of the antibody-antigen pair. The measurement of K -7 dissociation constant (Kd) of the antibody-antigen pair. The measurement of K -8 dissociation constant (Kd) of the antibody-antigen pair. The measurement of K D dissociation constant (Kd) of the antibody-antigen pair. The measurement of K D dissociation constant (Kd) of the antibody-antigen pair. The measurement of K

[0077] In the present context, the term "effector function" refers to those biological activities attributable to the Fc-region of an antibody, which vary with the class of the antibody, IgG Fc- regions are known to mediate several important effector functions. In one embodiment, the present disclosure provides antibodies having an Fc-region that elicits effector functions such as ADCC or CDC, thereby inducing tumor cell apoptosis, cytolysis, and / or inhibiting proliferation, dissemination and / or metastasis of tumor cells bearing the cognate antigen. In other embodiments, the present disclosure also provides antibodies having an Fc-region with altered effector functions. Effector functions can be altered by making sequence changes to the Fc-region of the antibody. Alternatively, antibodies can be made with altered types of glycosylation of the Fc-region. Alteration of the Fc-region glycosylation pattern can be conveniently achieved by altering the amino acid sequence of the Fc-region so as to create or remove one or more glycosylation sites.

[0078] In the present context, the term "HER2" (also known as ERBB2; NEU; NGL; TKR1; CD340; pi 85; MLN19; HER-2 / neu) refers to a transmembrane tyrosine kinase receptor of the epidermal growth factor (EGF) receptor family. HER2 comprises an extracellular binding domain, a transmembrane domain, and an intracellular tyrosine kinase domain. HER2 does not have its own ligand binding domain and therefore cannot bind growth factors, however, HER2 tightly associates with other ligand-bound EGF receptor family members such as HER1 or HER3 to form heterodimers, thereby stabilizing ligand binding and enhancing activation of the kinase-mediated downstream signaling pathways. The human HER2 / NEU gene is located at chromosomal location 17ql2, and the genomic sequence of the HER2 / NEU gene can be found in GenBank at NG_007503.1. In humans, there are five HER2 isoforms: A, B, C, D, and E; the term "HER2" is used herein to collectively refer to all HER2 isoforms. As used herein, a human HER2 protein also includes a protein having at least about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity over its entire length to a HER2 isoform A, B, C, D, and E, wherein such a protein still has at least one function of HER2.

[0079] In the present context, the term "HER2-positive cancer" or "HER2-expressing cancer" is a cancer comprising cells in which HER2 protein is present on the cell surface, the presence of HER2 on cancer cells can be detected or determined using methods known in the art.

[0080] In the present text, the terms "epidermal growth factor receptor" or "EGFR" are used interchangeably and comprise, unless otherwise indicated, any variant of human EGFR, including sequence variants, especially naturally occurring variants, allelic variants, as well as post-translationally modified variants and conformational variants, and encompass species homologues thereof. Furthermore, it is understood that the term encompasses EGFR expressed on a natural or recombinant cell. One example of EGFR is the human EGFR protein comprising the amino acid sequence under UniProtKB - P00533. In the present text, the terms "epidermal growth factor receptor" or "EGFR" refer to an epidermal growth factor receptor derived from a human, unless specifically indicated otherwise.

[0081] In the present text, the term "EGFR-positive" tumor cell refers to a tumor cell positive for EGFR cell surface expression, including, but not limited to, EGFR-positive breast cancer cells and lung cancer cells.

[0082] In the present text, the term "linker unit" or "linker" refers to a bifunctional or multifunctional moiety that covalently links a drug to an antibody in an antibody-drug conjugate. It can be cleavable or non-cleavable. The linker unit of the present disclosure has multiple components, such as a self-immolative linker; a cleavable linker; an optional property modulating unit; and an antibody attachment head.

[0083] In the present text, the term "self-immolative linker" refers to a temporary extender, spacer, or placeholder unit that links two or more molecules together through chemical bonds that break under defined conditions to release the two molecules. A self-immolative linker can be defined as a bifunctional chemical group that is capable of covalently linking two spaced apart chemical moieties together, forming a generally stable molecule, releasing one of the spaced apart chemical moieties from the molecule through enzymatic cleavage; and following the enzymatic cleavage, spontaneously cleaving from the remaining portion of the bifunctional chemical group to release the other of the spaced apart chemical moieties. In some embodiments, a self-immolative linker refers to a heterocyclic self-immolative moiety. Typical self-immolative linkers include p-aminobenzyl, p-hydroxybenzyl, p-aminobenzyloxy carbonyl (PABC), p-hydroxybenzyloxy carbonyl, 2,4-bis(hydroxymethyl)aniline, 2-aminomethyl-1-carbonylpiperidine, 2-aminomethyl-1-carbonylpiperazine, -NH-(CH2)4-C(O)-, and -NH-(CH2)3-C(O)-, etc.

[0084] In the present context, the term "cleavable linker" refers to a moiety in the linker unit of an ADC which is unstable in vivo, cleaved by the biological environment. Preferably, the "cleavable linker" allows activation of the label or therapeutic agent by cleaving the label or agent from the rest of the conjugate. The cleavage can come from any process without limitation, such as enzymatic, reduction, pH, etc. Preferably, the cleavable group is selected so that the activation occurs at the desired site of action, which can be a site in or near the target cell (e.g. cancer cell) or tissue, such as a site of therapeutic action or label activity. Such cleavage can be enzymatic, and exemplary enzymatic groups include but are not limited to a natural amino acid or a peptide sequence ending in a natural amino acid, and linked at its carboxyl terminus to the linker unit or a self-immolative linker.

[0085] In the present context, the term "antibody linker" refers to any chemical group designed to facilitate the attachment of a drug conjugate to an antibody, for example to overcome steric hindrance.

[0086] In the present context, the term "property modulating unit" refers to a functional moiety linked in the linker unit of an ADC in a tandem or branched manner, intended to modulate the properties of the ADC, such as stability in blood circulation, improved hydrophilicity, etc. Commonly used property modulating units of ADCs include but are not limited to polyethylene glycol (PEG), hydrophilic peptides, monosaccharides, oligosaccharides, polysaccharides, cyclodextrin units, sulfonamide fragments, sulfonic acid groups, phosphonic acid groups, polyamines, polyamides, dendrimers and bifunctional hydrocarbon chains, etc.

[0087] In the present context, the term "solubilizing unit" refers to a functional moiety linked in the linker unit of an ADC in a tandem or branched manner to increase solubility, with specific examples including "solubilizing sugar units", which refer to sugar units directly or indirectly linked to the self-immolative linker portion of the linker, for example. In the ADCs of the present disclosure, the introduction of a sugar group (e.g. monosaccharide, disaccharide, oligosaccharide, polysaccharide or derivative thereof) in the linker unit helps to improve the hydrophilicity of the conjugated chain, increase the loading rate to the theoretical maximum, while improving the solubility and purity of the conjugate, reducing the degree of aggregation, improving the drugability of the conjugate and ultimately improving the effect of inhibiting the proliferation of tumor cells.

[0088] In the present disclosure, "monosaccharide" as a solubilizing unit or a part thereof refers to a polyhydroxy aldehyde (aldose) or a polyhydroxy ketone (ketose) containing 3 or more carbon atoms and derivatives thereof, which is a basic structural unit constituting saccharides and their complexes, which cannot be hydrolyzed further and is not connected to other similar units by glycosidic bond. According to the number of carbon atoms in the monosaccharide, monosaccharides can also be classified into triose (triose), tetraose (tetrose), pentose (pentose), hexose (hexose), heptose (heptose), etc. It is preferable that the ADC of the present disclosure carries pentose or hexose. The derivatives of the monosaccharide include, for example, phosphate esters of monosaccharides, sugar alcohols, sugar acids, deoxy sugars, amino sugars, acylated amino sugars, and glycosides. Examples of the monosaccharide or its derivatives include, but are not limited to, glyceraldehyde, glyceraldehyde phosphate, dihydroxyacetone phosphate, erythrose, erythrulose, threose, arabinose, ribose, ribulose, deoxyribose, ribitol, ribose phosphate, xylose, xylulose, xylitol, lyxose, glucose, glucosamine, acetylglucosamine, glucuronic acid, acetylglucosaminic acid, glucose phosphate, mannose, mannitol, aminomannitol, acetylmannosamine, fructose, fructose phosphate, galactose, galactitol, galactosamine, acetyl galactosamine, allose, deoxyallose, altrose, deoxyaltrose, quinovose, muramic acid, psicose, sorbose, sorbitol, tagose, gulose, deoxygulose, idose, talose, fucose, deoxytalose, etc.

[0089] It should be noted that the monosaccharide and its derivatives of the present disclosure include D configuration, L configuration, racemate (DL), and meso, and also include any optically active form ((+), (-), (±)). The monosaccharide and its derivatives of the present disclosure include chain isomers, cyclic isomers, or mixtures thereof, wherein the cyclic form includes α-type anomeric and β-type anomeric, and for example, includes pyranose form or furanose form.

[0090] In the present disclosure, "disaccharide" as a property adjusting unit or a solubilizing unit refers to a compound in which two monosaccharides are connected by a glycosidic bond and derivatives thereof, which is classified into two types depending on the connection method: one is a non-reducing sugar in which the hemiacetal (hemiketal) hydroxyl group of two sugars is dehydrated to form a glycoside, which is a glycosyl glycoside; the other is a reducing sugar in which the hemiacetal (hemiketal) hydroxyl group of one sugar is glycosidically connected to the non-hemiacetal (hemiketal) hydroxyl group of the other sugar, which is a glycosyl sugar. The glycosidic bond can be an α-1,4 glycosidic bond, an α-1,6 glycosidic bond, a β-1,4 glycosidic bond, an α-1-2β glycosidic bond, a β-1,6 glycosidic bond, an α-1,1 glycosidic bond, a β-1,3 glycosidic bond, a β-2,1 glycosidic bond, and specific examples of the disaccharide include, but are not limited to, maltose, isomaltose, lactose, sucrose, chitobiose, citrullose, trehalose, xylobiose, gentiobiose, etc., wherein the monosaccharide unit constituting the disaccharide can be in the form of each type of monosaccharide derivative as described above.

[0091] In the present text, the term "oligosaccharide" refers to a lowly polymerized saccharide of 3 to 9 monosaccharides linked by glycosidic bonds and derivatives thereof, wherein the monosaccharides, the glycosidic bonds and the derivatives are as defined above, such as, but not limited to, manninotriose, globotriose, gentiatriose, stachyose, viscose, gossypetetraose, etc.

[0092] In the present text, the term "polysaccharide" refers to a saccharide of 10 or more monosaccharide units linked by glycosidic bonds, which can be of the alpha type or of the beta type or of the alpha / beta mixed type, and which can be linear, branched or cyclic in structure. The polysaccharide can be a homo-polysaccharide consisting of one type of monosaccharide selected from the group consisting of triose, tetrose, pentose, hexose, heptose and octose or deoxy sugar units, such as dextran, xylan, polysialic acid, etc., or a hetero-polysaccharide consisting of two or more types of monosaccharides, such as hyaluronic acid, heparin, etc. Examples of polysaccharides include, but are not limited to, dextran, levodextran, hyaluronic acid, cyclodextrin (alpha, beta and gamma, etc.), hydroxyethyl starch, xylan, water-soluble starch, water-soluble cellulose, carboxymethyl cellulose, galactosamine, polysialic acid, rhamnose, ganoderma polysaccharide, lentinan, chitin, chitosan, alginate, carrageenan, gellan gum, pullulan, scleroglucan, xanthan gum, xyloglucan, amylose, etc. The polysaccharide can be structurally modified or unmodified and can have one or more substituents selected from the group consisting of carboxylic acid group, carboxylic acid salt group, amino group, sulfonic acid group, sulfonic acid salt group, phosphoric acid group, phosphoric acid salt group, hydroxyethyl group, hydroxypropyl group, methyl group, acyl group, carboxymethyl group, natural amino acid group, unnatural amino acid group, etc.

[0093] In the present text, the term "derivative" used in the description of a saccharide unit mainly refers to phosphate ester (saccharide compound in which one or more hydroxyl groups of a saccharide are esterified with phosphoric acid), sugar alcohol (saccharide compound in which a carbonyl group of a saccharide is reduced to OH), sugar acid (aldonic acid in which an aldehyde group of an aldose is oxidized to carboxyl group, uronic acid in which a primary alcohol group of an aldose is oxidized to carboxyl group, and saccharide diacid in which both an aldehyde group and a primary alcohol group of an aldose are oxidized to carboxyl groups), deoxy sugar (saccharide in which one or both of the hydroxyl groups of a saccharide molecule are replaced with hydrogen atoms), amino sugar (saccharide derivative in which one or more hydroxyl groups of a saccharide molecule are replaced with amino group), acylated amino sugar (saccharide derivative in which an amino group of an amino sugar is acylated), and glycosidic form (saccharide derivative in which a hemiacetal hydroxyl group of a saccharide is condensed with a hydroxyl group, an amine group or a thiol group of another molecule such as an alcohol, a saccharide, a purine or a pyrimidine, i.e., a derivative in which a saccharide residue (saccharide minus the hemiacetal hydroxyl group) and a ligand are linked by a glycosidic bond). The term also includes compounds in which a saccharide unit is derivatized with more than one type of derivative.

[0094] The sugar derivative suitable for the ADC of the present disclosure can also be a derivative formed by derivatization of a sugar molecule in one or more of the above manners, for example acylated amino sugar uronic acid, for example 2-acetamido-2-deoxy-D-galacturonic acid, 2-acetamido-2-deoxy-D-glucuronic acid, 2-acetamido-2-deoxy-D-mannuronic acid.

[0095] In the present context, specific examples of the term "property modulating unit" or "solubilizing unit" also include "hydrophilic peptides". The term "hydrophilic peptide" can be attached, for example, to the self-immolative linker of the linker unit, or can be attached to the antibody linker, which can be directly attached to the linker unit, or attached to the linker unit via a suitable structural fragment, such as a fragment of formula (S) as defined for S1 or S2 of the present disclosure. In particular, the "hydrophilic peptide" can be an organic moiety comprising repeating subunits -CO-CR'R"-NR-, wherein one or more amino acids, identical or different from each other, are linked via amide bonds, in linear, branched or star-shaped configuration, each hydrophilic peptide generally comprising 1-20 amino acids, preferably 4-14 amino acids, more preferably 6-12 or 5-10 amino acids.

[0096] In the present context, the amino acid monomers constituting the hydrophilic peptide can be natural amino acids, such as alanine (Ala), arginine (Arg), aspartic acid (Asp), asparagine (Asn), histidine (His), glycine (Gly), glutamic acid (Glu), glutamine (Gin), phenylalanine (Phe), lysine (Lys), leucine (Leu), serine (Ser), tyrosine (Tyr), threonine (Thr), isoleucine (lie), proline (Pro), tryptophan (Trp), valine (Val), cysteine (Cys), methionine (Met), respectively, for example R in the repeating subunit -CO-CR'R"-NR- is H and one of R' and R" is H, the other corresponding to the respective group or fragment in the respective natural amino acid; preferably polar natural amino acids, such as arginine, serine, threonine, tyrosine, cysteine, aspartic acid, asparagine, glutamic acid, glutamine, lysine, histidine, glycine, tryptophan.

[0097] In the present context, the amino acid monomers constituting the hydrophilic peptide can also be amino acids other than the above-mentioned twenty natural amino acids, such as ornithine (Orn), beta-alanine (beta-Ala), citrulline (Cit), sarcosine (Sar), and those amino acids in which R, R', R" in the repeating subunit -CO-CR'R"-NR- are different from the corresponding groups or fragments in natural amino acids, such as R, R', R" are selected from alkyl, aryl, acyl, amido, ketone, azido, hydroxyl, thiol, hydrazine, cyano, quaternary ammonium, halogen, hydrazide, alkenyl, alkynyl, ether, thiol, seleno, sulfonic, sulfuric, boronic ester, phosphono, phosphoric, heterocycle, enone, imine, aldehyde, ester, thioacid, hydroxylamine, amino, etc. or any combination thereof, or a group comprising alkyl, aryl, acyl, amido, ketone, azido, hydroxyl, thiol, hydrazine, cyano, quaternary ammonium, halogen, hydrazide, alkenyl, alkynyl, ether, thiol, seleno, sulfonic, sulfuric, boronic ester, phosphono, phosphoric, heterocycle, enone, imine, aldehyde, ester, thioacid, hydroxylamine, amino, etc.; preferably those amino acids in which R, R' and / or R" comprise a hydrophilic group, such as R, R', R" are each independently carboxyl, sulfonic, sulfuric, phosphoric, amino, amido, quaternary ammonium, oxygen-containing group, ether group, thiol or hydroxyl, or a group comprising carboxyl, sulfonic, sulfuric, phosphoric, amino, amido, quaternary ammonium, oxygen-containing group, ether group, thiol and / or hydroxyl, such as alkyl, e.g. C 1-6 alkyl.

[0098] For the ADC of the present disclosure, when the linker unit carries a hydrophilic peptide, at least 50% to 100% of the amino acids constituting the hydrophilic peptide are hydrophilic amino acids, such as 80%-100%, such as 60%, 70%, 80%, 90% or 100%, which are preferably arginine, serine, threonine, tyrosine, cysteine, aspartic acid, asparagine, glutamic acid, glutamine, lysine, histidine, glycine, tryptophan, ornithine, citrulline (Cit), sarcosine (Sar).

[0099] For the ADC of the present disclosure, the hydrophilic peptide carried by the linker unit is preferably a poly-sarcosine, poly-arginine, poly-glycine of 4-14 units, more preferably a poly-sarcosine of 6-12 units or 5-10 units.

[0100] In the present context, the term "PEG unit" refers to an organic moiety comprising repeating ethyleneoxy subunits (PEG or PEG subunits), which can be polydisperse, monodisperse or discrete (i.e. having a discrete number of ethylene-oxyl subunits).

[0101] The PEG units provided herein can be linked together, for example, in linear, branched, or star configurations. Typically, at least one polyethylene glycol chain is derivatized at one end with an alkyl moiety substituted with an electrophilic group, for example, to a carbamate nitrogen of a methylene carbamate unit, prior to incorporation into the ADC. The terminal ethyleneoxy group (if present) in the polyethylene glycol chain that does not participate in covalent attachment to the remainder of the linker unit is modified with a PEG capping unit, typically an optionally substituted alkyl group, such as -CH3, CH2CH3, or CH2CH2CO2H. Preferred PEG units have a single polyethylene glycol chain having 2 to 24 -CH2CH2O- subunits covalently linked in series.

[0102] In this document, the term "base" refers to the nitrogen-containing biological compound within a nucleoside that is linked to a sugar, i.e., the basic building unit of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). The naturally occurring nucleobases are cytosine (DNA and RNA), guanine (DNA and RNA), adenine (DNA and RNA), thymine (DNA), and uracil (RNA), abbreviated C, G, A, T, U, respectively.

[0103] In the present context, the term "drug: antibody ratio" or "DAR" refers to the ratio of drug moieties (D) conjugated to an Ab moiety described herein to the Ab moiety in an ADC conjugate. In some embodiments described herein, the DAR can be determined by the value of q in the general formula, e.g. the DAR can be an integer or a non-integer of at least 1, e.g. about 1 to 20, e.g. about 2-18, 4-16, 5-12, 1-10, 1-8, 2-8, 3-8, 2-6, 4-6, 4-8, 6-8, 6-10, e.g. 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15. The DAR can also be calculated as the average DAR of the population of molecules in the product, i.e. the overall ratio of small molecule drug moieties (D) conjugated to an Ab moiety described herein to the Ab moiety in the product as measured by detection methods, e.g. by conventional methods such as mass spectrometry, ELISA assays, electrophoresis and / or HPLC, which DAR is referred to herein as the average DAR. In some embodiments, the average DAR value of the conjugates of the application is about 1 to 20, e.g. about 2-18, 4-16, 5-12, 1-10, 1-8, 2-8, 3-8, 2-6, 4-6, 4-8, 6-8, 6-10, e.g. 1.0-8.0, 2.0-6.0, e.g. about 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8.0, 7.9, 8, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, or 10.0, in a range with two of these values as endpoints.

[0104] In the present context, the term "halogen" generally refers to fluorine, chlorine, bromine, iodine, e.g. can be fluorine, chlorine.

[0105] In the present text, the term "alkyl" refers to a straight-chain or branched-chain aliphatic saturated hydrocarbon group having the number of carbon atoms indicated. Specifically, alkyl groups can have 1 to 20, 1 to 14, 1 to 12, 1 to 10, 1 to 8, 1 to 7, 1 to 6, 1 to 5, 1 to 4, 1 to 3, or 1 to 2 carbon atoms. Suitable C 1-14 Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl, n-pentyl, i-pentyl, neopentyl, n-hexyl, i-hexyl, dimethylmethyl, dipropylmethyl, ethylbutylmethyl, diethylmethyl, methylethylmethyl, ethylpropylmethyl, diethyl ethyl, diethylpropyl, dipropylethyl, and the like. Particular alkyl groups have 1 to 7 carbon atoms, for example 1 to 6 carbon atoms, 1 to 4 carbon atoms.

[0106] In the present text, the term "alkylene" refers to a divalent group obtained by removing two hydrogen atoms from the same or two different carbon atoms of a straight-chain or branched-chain saturated alkane. Specifically, alkylene groups have 1 to 10 carbon atoms, for example 1 to 6, 1 to 5, 1 to 4, 1 to 3, or 1 to 2 carbon atoms. For example, as used herein, the term "C 1-5 alkylene" refers to a straight-chain or branched-chain alkylene group having 1 to 5 carbon atoms, including but not limited to methylene, ethylene, propylene, butylene, and the like.

[0107] In the present text, the term "-O-alkyl" or "alkoxy" means an alkyl group as defined herein attached to the rest of the molecule through an oxygen atom. Specifically, -O-alkyl groups have 1 to 10, for example 1 to 8, 1 to 6, 1 to 5, 1 to 4, 1 to 3, or 1 to 2 carbon atoms. For example, as used herein, the term "-O-C 1-6 alkyl" refers to a straight-chain or branched-chain saturated hydrocarbon group having 1 to 6 carbon atoms attached to the rest of the molecule through an oxygen atom, examples of which are, for example, -O-methyl, -O-ethyl, -O-propyl (including -O-n-propyl and -O-i-propyl), -O-butyl (including -O-n-butyl, -O-i-butyl, -O-s-butyl, or -O-t-butyl), -O-pentyl (including -O-n-pentyl, -O-i-pentyl, -O-neopentyl), -O-n-hexyl, 2-methylpentyl-O-, and the like.

[0108] In the present text, the term "alkyl optionally substituted with halogen" refers to an alkyl group as described herein, wherein one or more (e.g. 1, 2, 3, 4 or 5) hydrogen atoms are optionally replaced by halogen. It will be understood by a person skilled in the art that when there is more than one halogen substituent, the halogens can be the same or different and can be located on the same or different C atoms. Examples of "halogen-substituted C1-6alkyl" are, for example, -CH2F, -CHF2, -CF3, -CC13, -C2F5, -C2C15, -CH2CF3, -CH2CI, -CH2CH2CF3, or -CF(CF3)2, etc.

[0109] In the present text, the term "alkenyl" refers to a straight-chain or branched unsaturated hydrocarbon group consisting of carbon and hydrogen atoms comprising at least one double bond. Specifically, alkenyl groups have 2 to 20, 2 to 10, 2 to 8, for example 2 to 6, 2 to 5, 2 to 4, or 2 to 3 carbon atoms. For example, as used herein, the term "C2-C6alkenyl" refers to straight-chain or branched alkenyl groups having 2 to 6 carbon atoms, for example ethenyl, propenyl, allyl, 1 -butenyl, 2-butenyl, 1,3-butenyl, 1 -pentenyl, 2-pentenyl, 3-pentenyl, 1,3-pentadienyl, 1,4-pentadienyl, 1 -hexenyl, 2-hexenyl, 3-hexenyl, 1,4-hexadienyl, and the like. The carbon atom through which the alkenyl group is attached to the rest of the molecule can be either a saturated or an olefinic carbon atom.

[0110] In the present text, the term "cycloalkyl" refers to a monocyclic, fused polycyclic, bridged polycyclic, or spirocyclic non-aromatic monovalent hydrocarbon ring structure having the number of ring atoms specified, which can be saturated or unsaturated, for example containing 1 or more double bonds, preferably saturated. The cycloalkyl group can contain 3 or more, for example 3 to 10 or 3 to 8 carbon atoms in the ring, for example C3-C10cycloalkyl, C3-C8cycloalkyl, C3-C6cycloalkyl, or C5-C6cycloalkyl. Examples of cycloalkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl. 3-10 cycloalkyl, C 3-8 cycloalkyl, C 3-6 cycloalkyl, C 5-6 cycloalkyl. Examples of cycloalkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl.

[0111] In the present text, the term "heterocycle" or "heterocyclyl" refers to a 5-20 membered (e.g. 5-14 membered, 5-10 membered, 5-8 membered, 5-6 membered) aromatic or non-aromatic monocyclic, bicyclic, or polycyclic ring system having 1-4 ring heteroatoms independently selected from N, O, or S. One or more N, C, or S atoms in a heterocycle can be oxidized. Preferably, the heterocycle is a 5-10 membered ring system, e.g. a heteroaryl, heterocycloalkyl, each of which can be monocyclic or fused bicyclic, comprising 1 or 2 heteroatoms, more preferably a 5-6 membered monocyclic heteroaryl or heterocycloalkyl. Representative examples include, but are not limited to, pyrrolidine, succinimide (2,5-dioxopyrrolidine), piperidine, morpholine, tetrahydrofuran, tetrahydropyran, benzofuran, benzothiophene, indole, benzopyrazole, pyrrole, thiophene (thiene), furan, thiazole, imidazole, pyrazole, pyrimidine, pyridine, pyrazine, pyridazine, isothiazole, and isoxazole.

[0112] In the present text, the term "heterocycloalkyl" means a monocyclic, fused polycyclic, spirocyclic or bridged polycyclic saturated ring structure including 1-4 heteroatoms independently selected from O, N and S and the indicated number of ring atoms, or an N-oxide, S-oxide or C-oxide thereof. The heterocycloalkyl group can have, for example, 5 to 12 ring members (may be referred to as 5-12 membered heterocycloalkyl), for example, 5 to 10 ring members, 5 to 8 ring members, 5 to 7 ring members, 5 to 6 ring members. The heterocycloalkyl group typically contains, for example, 1-4 heteroatoms, for example, a 5-6 membered heterocycloalkyl group containing 1 to 2 heteroatoms selected from N, O, S. The atom to which the heterocycloalkyl group is attached to the rest of the compound can be a carbon atom or a heteroatom, as chemically feasible.

[0113] In the present text, the term "heteroaryl" refers to a 5-20 membered (e.g. 5-14 membered, 5-10 membered, 5-8 membered, 5-6 membered) aromatic monocyclic or polycyclic ring system containing 1-4 heteroatoms independently selected from N, O, or S, which can be substituted or unsubstituted. Preferably, the heteroaryl is a 5-10 membered ring system, monocyclic or fused bicyclic, comprising 1-2 heteroatoms, more preferably a 5-6 membered heteroaryl.

[0114] For clarity, the term "guanine" as used herein may also be represented as The phosphorothioate group used in the structural formula of the compounds of the present disclosure can be drawn as

[0115] Unless otherwise specified, C n-n+m or C n -C m includes various instances of n to n+m carbons, for example, C 1-6including C1, C2, C3, C4, C5, and C6, also including any range from n to n+m, for example C 0-6 including C1, C2, C3, C4, C5, C6, C 0-1 , C 0-2 , C 0-3 , C 0-4 , C 0-5 , C 1-2 , C 1-3 , C 1-4 , C 2-3 , C 1-6 including C 1-2 , C 1-3 , C 1-4 , C 2-6 , C 3-6 , etc.

[0116] In the present context, the term "pharmaceutically acceptable salt" denotes a salt that retains the biological effectiveness and properties of the ADCs of the present disclosure and that is not biologically or otherwise undesirable. The ADCs of the present disclosure can exist in the form of their pharmaceutically acceptable salts, including acid and base addition salts. In the present disclosure, a pharmaceutically acceptable, nontoxic acid addition salt is meant to include salts of acidic groups in the ADCs of the present disclosure with inorganic or organic acids including, but not limited to, hydrochloric, sulfuric, hydrobromic, hydroiodic, phosphoric, nitric, perchloric, acetic, oxalic, maleic, fumaric, tartaric, benzenesulfonic, methanesulfonic, salicylic, succinic, citric, lactic, propionic, benzoic, p-toluenesulfonic, malic, and the like. A pharmaceutically acceptable, nontoxic base addition salt is meant to include salts of acidic groups in the ADCs of the present disclosure with organic or inorganic bases including, but not limited to, alkali metal salts, such as lithium, sodium or potassium salts; alkaline earth metal salts, such as calcium or magnesium salts; organic base salts, such as ammonium salts with organic bases including N-containing groups.

[0117] In the present context, the term "solvate" denotes an association or complex of one or more solvent molecules and an ADC of the present disclosure. Solvents which form solvates include, but are not limited to, water, methanol, ethanol, isopropanol, ethyl acetate, tetrahydrofuran, N,N-dimethylformamide, dimethyl sulfoxide, and the like. It is understood that such solvates also include pharmaceutically acceptable salts of the compounds of the present disclosure.

[0118] In the present context, the term "isotopic variant" refers to a compound in which one or more atoms of the compound are replaced by an atom having an atomic mass or mass number different from the atomic mass or mass number usually found in nature. Examples of isotopes which can be incorporated into one or more atoms of the compounds of the present disclosure include, for example 2 H, 3 H, 13 C, 14C、 15 N、 17 O、 18 O、 31 P、 32 P、 35 S and 18 F, to thereby form isotopically-labeled forms of compounds of the present disclosure. Such isotopically-labeled compounds are intended to be encompassed within the scope of the present disclosure. In some embodiments, the isotopically-labeled compound is 2 H (deuterium); and in other embodiments, the isotopically-labeled compound is 3 H (tritium).

[0119] The term "prodrug" herein refers to a chemical derivative of an ADC of the present disclosure that is converted into an ADC of the present disclosure by chemical reaction in vivo.

[0120] The term "isomer" herein refers to any of the stereoisomers, mixtures of enantiomers, including racemates, mixtures of diastereoisomers, geometric isomers, atropisomers, and / or tautomers that the compound can exist in. Methods for the determination and separation of the stereochemistry of the isomers are well known to one skilled in the art (S. P. Parker, Ed., McGraw-Hill Dictionary of Chemical Terms (1984) McGraw-Hill Book Company, New York; and Eliel, E. and Wilen, S., "Stereochemistry of Organic Compounds", John Wiley & Sons, Inc., New York, 1994). The present disclosure encompasses all possible isomer forms of the compounds defined herein, and pharmaceutically acceptable salts or solvates thereof, unless indicated otherwise. Additionally, the compounds of the present disclosure can exist as mixtures of two or more different structural forms in rapid equilibrium (often referred to as tautomers). It is intended that the scope of the present application encompass all such isomers or mixtures thereof in any proportion (e.g., 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%).

[0121] In the present text, the term "stereoisomer" denotes isomers formed due to at least one asymmetric center. In compounds having one or more (e.g. 1, 2, 3 or 4) asymmetric centers, they can give rise to racemic mixtures, single enantiomers, mixtures of diastereomers and individual diastereomers. Similarly, the compounds of the present disclosure can exist in mixtures of two or more different structural forms in rapid equilibrium (commonly known as tautomers). It is to be understood that the scope of the present application encompasses all such isomers or mixtures thereof in any ratio (e.g. 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%).

[0122] The compounds of the present disclosure can have one or more asymmetric centers and can therefore be prepared in the form of (R)- or (S)-stereoisomers, respectively, or as mixtures thereof. The configuration of the asymmetric centers, i.e. the chiral centers, is indicated in the structural formulae or structural fragments of the compounds used herein by the symbols R and S. Accordingly, the configuration about the chiral center is indicated by R and S in the nomenclature of the compounds or intermediates provided by the present disclosure. The skilled person will be aware that the phosphorothioate linkage in the compounds of the present disclosure is inherently chiral and can exist in the R or S configuration, respectively, so that both phosphorothioate linkages in the R,R, S,S, S,R and R,S forms are possible. The present disclosure encompasses the compounds of the present disclosure and their specific embodiments in substantially pure form or in mixtures, the compounds having two phosphorothioate linkages preferably being in the R,R, S,S, S,R and R,S stereoisomers in substantially pure form, particularly preferably the substantially pure R,R stereoisomer, i.e. both phosphorus atoms having the R configuration. Their absolute configuration assignment can be performed according to literature methods (Zhao et al. Nucleosides, Nucleotides and Nucleic Acids 2009, 289, 352-378; Knouse et al. Science 2018, 361, 1234). It is to be noted that a misassignment of the configuration based on an error in the literature method does not affect the actual configuration of the compounds of the present disclosure.

[0123] As used herein with respect to CDNs, the term "substantially pure" means that a certain stereochemical form is at least 75% pure with respect to other possible stereochemical forms at the chiral centers. In preferred embodiments, a substantially pure CDN is at least 85% pure, at least 90% pure, at least 95% pure, at least 97% pure, and at least 99% pure. A substantially pure CDN preparation of the present disclosure is "stereochemically pure" in that all of the CDNs within the preparation have a particular stereochemical configuration at these chiral centers, and is not intended to indicate that all of the CDNs within the preparation having the particular stereochemical configuration at these chiral centers are otherwise identical. For example, a substantially pure CDN R,R cGAMP thio phosphate preparation can comprise a combination of R,R c-di-GMP thio phosphate and R,R c-di-AMP thio phosphate, and still be a substantially pure cyclic purine dinucleotide preparation.

[0124] It should be understood that, where a compound herein is capable of existing in a pair of enantiomeric forms, and it is judged by one of ordinary skill in the art, based on the structure of the compound as depicted herein, that the pair of enantiomeric forms can be readily resolved based on routine methods in the art, then a disclosure of a racemate of the compound (whether by structural formula or chemical name) herein is to be understood as having separately disclosed each of the enantiomeric forms of the compound.

[0125] In the present text, the number of groups attached to an atom in a compound definition, a compound structural formula, or a structural fragment depends on the valency of the atom, and is not necessarily all shown. In general, only non-hydrogen groups are shown in a group definition, structural formula, or structural fragment, and the unshown groups are typically H, as can be readily determined by one of ordinary skill in the art.

[0126] As used in structural fragments herein indicates the bond to which it crosses is the bond to the rest of the molecule.

[0127] In the present text, the terms "pharmaceutically acceptable excipient," "pharmaceutically acceptable carrier," and "therapeutically inert excipient" are used interchangeably, and refer to any pharmaceutically acceptable ingredient in a pharmaceutical composition, which does not have therapeutic activity and is non-toxic to the subject to which the pharmaceutical composition is administered, such as a disintegrant, a binder, a filler, a solvent, a buffer, a tonicity agent, a stabilizer, an antioxidant, a surfactant, a carrier, a diluent, or a lubricant used in formulating a pharmaceutical product.

[0128] In the present context, the term "pharmaceutical combination" refers to a non-fixed combination product or a fixed combination product, including but not limited to a kit, a pharmaceutical composition. The term "non-fixed combination" means that the active ingredients, e.g., (i) an ADC of the present disclosure, and (ii) the other therapeutic agent, are presented for administration to a patient as separate entities, either simultaneously, without specific time limitations, or sequentially in any order, where such administration provides therapeutically effective levels of the two or more active agents in the body of the patient. In some embodiments, the ADC of the present disclosure and the other therapeutic agent used in the pharmaceutical combination are administered at levels that would not be effective for treatment if they were to be administered individually. The term "fixed combination" means that the two or more active agents are administered to a patient as a single entity. Preferably, the dosage and / or time intervals of the two or more active agents are selected so that a combined use of the individual parts results in an effect that is greater than the effect that would result from the use of each ingredient alone. The individual ingredients can each be present in separate formulations which can be the same or different.

[0129] In the present context, the term "individual" or "subject" is used interchangeably and refers to a mammal. Mammals include, but are not limited to, domesticated animals (e.g., cows, sheep, cats, dogs, and horses), primates (e.g., humans and non-human primates such as monkeys), rabbits, and rodents (e.g., mice and rats). In particular, the subject is a human.

[0130] In the present context, the term "treatment" refers to slowing, interrupting, arresting, relieving, stopping, reducing, or reversing the progression or severity of an existing symptom, disorder, condition, or disease.

[0131] In the present context, the term "prevention" includes inhibition of the occurrence or development of a disease or disorder or symptoms of a particular disease or disorder. In some embodiments, a subject with a family history of cancer is a candidate for a prophylactic regimen. Typically, in the context of cancer, the term "prevention" refers to the administration of a drug prior to the onset of signs or symptoms of cancer, particularly in a subject at risk for cancer.

[0132] In the present context, the term "therapeutically or prophylactically effective amount" refers to the amount or dose of an ADC of the present disclosure or a composition or combination thereof, which, upon single or multiple dose administration to a patient, results in an intended therapeutic or prophylactic effect in the patient in need of treatment or prevention.

[0133] Dual payload antibody-drug conjugates

[0134] In one aspect, the present disclosure provides an antibody-drug conjugate (ADC) having the following formula (X-1) or a pharmaceutically acceptable salt, ester, isomer, solvate, prodrug, or isotopically-labeled form thereof:

[0135] wherein,

[0136] Ab represents an antibody or antigen binding fragment;

[0137] D1 represents a first payload, a cyclic dinucleotide as defined herein (a compound of Formula (II), (II-a), (II-a'), (II-b), (II-b'));

[0138] D2 represents a second payload, as defined herein below;

[0139] L represents a linker unit connecting D1 and D2 to Ab;

[0140] q represents the number of For example, q is an integer or non-integer from about 1 to 20, e.g., 1-10, 1-8, 2-8, 3-10, 3-8, 4-10, 4-8, 6-8, or 6-10.

[0141] In some embodiments of Formula X-1, q represents an integer selected from 1 to 20, including 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20. In some cases, q ranges from 1 to 2, 1 to 3, 1 to 4, 1 to 5, 1 to 6, 1 to 7, 1 to 8, 1 to 9, 1 to 10, 1 to 11, 1 to 12, 1 to 13, 1 to 14, 1 to 15, 1 to 16, 1 to 17, 1 to 18, 1 to 19, or 1 to 20, or a range between any two of these values, e.g., 2 to 10, 2 to 8, 2 to 6, 2 to 4, 3 to 8, 3 to 10, 4 to 6, 4 to 8, 4 to 10, 6 to 8, or 6 to 10.

[0142] In some embodiments, Formula X-1 describes an ADC in a mixture of ADCs such that more than 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95% of the ADCs in the mixture have a q value of about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20. In some embodiments, Formula X-1 describes an ADC in a mixture of ADCs such that more than 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95% of the ADCs in the mixture have a q value ranging from about 1 to 2, 1 to 3, 1 to 4, 1 to 5, 1 to 6, 1 to 7, 1 to 8, 1 to 9, 1 to 10, 1 to 11, 1 to 12, 1 to 13, 1 to 14, 1 to 15, 1 to 16, 1 to 17, 1 to 18, 1 to 19, or 1 to 20, or a range between any two of these values, e.g., about 2 to 10, 2 to 8, 2 to 6, 2 to 4, 3 to 8, 3 to 10, 4 to 6, 4 to 8, 4 to 10, 6 to 8, or 6 to 10.

[0143] In other embodiments, Formula X-1 describes an ADC mixture, where q is "q 平均 ", which represents the average value of q for the mixture, i.e., the average number of linker units (L) attached to a given antibody (Ab) in the mixture. In such embodiments, q 平均 represents an integer or non-integer value of about 1 to 20, e.g., about 1 to 2, 1 to 3, 1 to 4, 1 to 5, 1 to 6, 1 to 7, 1 to 8, 1 to 9, 1 to 10, 1 to 11, 1 to 12, 1 to 13, 1 to 14, 1 to 15, 1 to 16, 1 to 17, 1 to 18, 1 to 19, or 1 to 20, or an integer or fraction within a range defined by any two of these values, e.g., about 2 to 10, 2 to 8, 2 to 6, 2 to 4, 3 to 8, 3 to 10, 4 to 6, 4 to 8, 4 to 10, 6 to 8, or 6 to 10.

[0144] In preferred embodiments, q in Formula X-1 of the present disclosure is an integer or non-integer of about 1 to 10 or a range defined by any two of these values, e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, about 1 to 2, 1 to 3, 1 to 4, 1 to 5, 1 to 6, 1 to 7, 1 to 8, 1 to 9, 1 to 10, 2 to 10, 2 to 8, 2 to 6, 2 to 4, 3 to 8, 3 to 10, 4 to 6, 4 to 8, 4 to 10, 6 to 8, or 6 to 10.

[0145] In some embodiments, q represents an average DAR of about 1-10, 1-8, 2-8, 3-10, 3-8, 4-10, 4-8, 6-8, or 6-10.

[0146] In some embodiments, q represents an average DAR of about 3. In some embodiments, q represents an average DAR of about 6. In some embodiments, q represents an average DAR of about 8.

[0147] It will also be appreciated by those skilled in the art that the various ADCs described herein can be pharmaceutically acceptable salts, esters, isomers, solvates, prodrugs, or isotopically labeled, and in some particular embodiments, are pharmaceutically acceptable salts.

[0148] In particular embodiments, the dual payload antibody-drug conjugates (ADCs) of Formula (X-1) of the present disclosure have the following subformula:

[0149] wherein:

[0150] Ab represents an antibody or antigen binding fragment;

[0151] D1represents a first payload, a cyclic dinucleotide as defined herein (compound of formula (II), (II-a), (II-a'), (II-b), (II-b'));

[0152] D2represents a second payload, as defined herein below;

[0153] G represents an antibody linker connected to Ab;

[0154] E represents an optional property modulating unit;

[0155] W represents a branching linker;

[0156] P1and P2are each independently a cleavable linker selected from a peptide residue of 2-8 amino acids, preferably a dipeptide, tripeptide or tetrapeptide;

[0157] A1and A2are each independently an optional self-immolative linker;

[0158] S1and S2are each independently an optional solubilizing unit;

[0159] q represents the number of linker unit-payload fragments connected to Ab, for example q is an integer or non-integer of about 1 to 20, for example about 1-10, 1-8, 3-8, 4-8 or 6-8.

[0160] In some embodiments, E is absent, formula (I) is

[0161] In some embodiments, E and S1are both absent, formula (I) is

[0162] In some embodiments, E, S1, S2are all absent, formula (I) is

[0163] In some embodiments, S1is absent, formula (I) is

[0164] In some embodiments, S2is absent, formula (I) is

[0165] In some embodiments, S1and S2are both absent, formula (I) is

[0166] The number of D1 or D2 attached to the antibody or antigen-binding fragment thereof of the ADC can vary (referred to as the "drug-to-antibody ratio" or "DAR") and will be limited by the number of available attachment sites on the antibody or antigen-binding fragment thereof and the number of D1 or D2 attached to a single linker. In an ADC comprising multiple D1 or D2, each D1 or D2 can be the same or different. ADCs with a DAR of 10 or even higher can be contemplated as long as the D1 or D2 do not exhibit unacceptable levels of aggregation under conditions of use and / or storage. In some embodiments, the ADCs described herein can have a DAR ranging from about 1 to 10, about 1 to 9, about 1 to 8, about 1 to 7, about 1 to 6, about 1 to 5, or about 1 to 4. In some embodiments, the ADCs described herein can have a DAR ranging from about 2 to 10, about 2 to 9, about 2 to 8, about 2 to 7, about 2 to 6, about 2 to 5, about 2 to 4, about 3 to 10, about 3 to 8, about 4 to 10, about 4 to 8, about 4 to 6, about 6 to 8, or about 6 to 10. In certain particular embodiments, the DAR of the ADC can be about 1, 2, 3, or 4. In other particular examples, the DAR of the ADC can be about 5, 6, 7, or 8.

[0167] The various components of the ADC of the present disclosure and the ADCs of the present disclosure comprised thereof are described in detail below, respectively. It will be understood by those skilled in the art that the ADCs disclosed herein are essentially "modular" in that each has the modular components Ab, L, and D described above. Throughout the present disclosure, various particular non-limiting embodiments and examples of these modular components are described, and the present disclosure encompasses all particular combinations of embodiments of the modules, as if each particular combination were expressly described individually.

[0168] Ab - antibody or antigen-binding fragment

[0169] In the CDN-ADCs of the present disclosure, the antibody is an antibody or antigen-binding fragment that specifically binds to a target antigen, the role of which is to target and present the CDN drug component to a particular target cell population with which the antibody or antigen-binding fragment interacts due to the presence of its targeting component or molecule, followed by the release of free drug within the target cell (intracellularly) or in the vicinity of the target cell (extracellularly).

[0170] The antibody or antigen binding fragment is bonded to the linker unit through a heteroatom. Heteroatoms that can be present on the antibody or antigen binding fragment for this bonding include sulfur (in one embodiment, from a thiol group of the targeting ligand), oxygen (in one embodiment, from a carboxyl or hydroxyl group of the targeting ligand), and optionally substituted nitrogen (in one embodiment, from a primary or secondary amine functional group of the targeting ligand, or in another embodiment, from an optionally substituted amide nitrogen). These heteroatoms can be present on the antibody unit in the natural state of the ligand, for example in a naturally occurring antibody, or can be introduced into the antibody unit by chemical modification or biological engineering.

[0171] In some embodiments, the antibody or antigen binding fragment is capable of forming a covalent bond between the linker unit and the antibody or antigen binding fragment corresponding to the antibody unit through interaction with a reactive functional group on the linker unit. The functional group that has the ability to interact with the antibody unit will depend on the nature of the antibody or antigen binding fragment. In some embodiments, the reactive group is a maleimide. Covalent attachment of the antibody or antigen binding fragment to the linker unit is achieved through interaction of a thiol functional group of the antibody or antigen binding fragment with a maleimide functional group of the linker unit, forming a sulfur substituted succinimide. The thiol functional group can be present in the natural state of the antibody or antigen binding fragment, for example in a naturally occurring residue, or can be introduced into the antibody or antigen binding fragment by reduction, chemical modification, or by biological engineering.

[0172] In some embodiments, the antibody or antigen binding fragment has a thiol functional group, such that it is bonded to the linker unit via the sulfur atom of the thiol functional group. In some embodiments, the thiol is produced by reduction of an interchain disulfide of the antibody, the linker unit being conjugated to a cysteine residue from the reduced interchain disulfide. In other embodiments, the thiol group is introduced into the antibody chemically, for example by introducing a cysteine residue, the linker unit being conjugated to the antibody or antigen binding fragment through the introduced cysteine residue in the antibody or antigen binding fragment.

[0173] In some embodiments, the antibody or antigen binding fragment has one or more lysine residues that are capable of reacting with an activated ester in the linker unit, including but not limited to N-hydroxysuccinimide, pentafluorophenyl, and p-nitrophenyl esters, and thereby providing an amide bond consisting of a nitrogen atom of the antibody or antigen binding fragment and a C=0 of the linker unit.

[0174] In other embodiments, the antibody or antigen-binding fragment has one or more lysine residues that are capable of being chemically modified to introduce one or more thiol groups. In these embodiments, the antibody or antigen-binding fragment is covalently attached to the linker unit via the sulfur atom of the thiol functional group. Reagents that can be used to modify lysines in this manner include, but are not limited to, N-succinimidyl-S-acetylthioacetate (SATA) and 2-iminothiolane hydrochloride (Traut's reagent).

[0175] In other embodiments, the antibody or antigen-binding fragment has one or more carbohydrate groups that are capable of being modified to provide one or more thiol functional groups. The chemically modified antibody or antigen-binding fragment in the ADC is bonded to the linker unit via the sulfur atom of the thiol functional group.

[0176] In other embodiments, the antibody or antigen-binding fragment has one or more carbohydrate groups that are capable of being oxidized to provide an aldehyde (-CHO) functional group. In these embodiments, the corresponding aldehyde interacts with a reactive site on the linker unit to form a chemical bond between the linker unit and the antibody unit.

[0177] Other schemes for modifying proteins for attachment to linker units or related species can be found in Coligan et al., Current Protocols in Protein Science, Vol. 2, John Wiley & Sons (2002), which is incorporated herein by reference.

[0178] The antibodies that make up the ADCs of the disclosure can be polyclonal, monoclonal, genetically engineered, and / or otherwise modified, and are preferably suitable for administration to humans, e.g., humanized antibodies or fully human antibodies.

[0179] In some embodiments, the Ab unit of the ADCs of the disclosure is a monospecific antibody. In some embodiments, the Ab unit of the ADCs of the disclosure is a multispecific antibody. In some embodiments, the Ab unit, upon binding to an antigen receptor expressed on the surface of a tumor cell, elicits endocytosis mediated by the antigen receptor, thereby effectively carrying the antitumor drug of the ADC into the tumor cell.

[0180] In some embodiments, the Ab unit of the ADCs of the disclosure can be a bispecific antibody, a dual variable domain antibody, a multi-chain or single-chain antibody, a single domain antibody, a camelized antibody, an scFv-Fc antibody, a substitute antibody, etc.

[0181] The present disclosure contemplates not only the use of monospecific antibody molecules as Ab units, but also the use of bispecific antibodies as Ab units. One specificity of the antibody can target a tumor-associated antigen to promote specific binding of the ADC to tumor cells; while the other specificity of the antibody can target a tumor cell surface receptor to further promote endocytosis and degradation of the ADC. Examples of such bispecific target combinations that can be mentioned include, but are not limited to, the HER2 and PRLR dual target combination on breast cancer cells. The two specificities of the antibody can also target different epitopes of the same tumor-associated antigen, respectively, to increase the selectivity of the antibody for cancer cells, and / or to enhance internalization and trafficking to lysosomes by inducing clustering and cross-linking of the antigen on the tumor cell surface. Examples of such tumor-associated antigens that can be mentioned include, but are not limited to, HER2 on breast cancer cells.

[0182] The antibody portion of the ADCs of the present disclosure can be in the form of a full-length antibody. The antibody portion of the ADCs of the present disclosure can be of or derived from any antibody isotype, including, for example, IgA, IgD, IgE, IgG, IgM, or IgY. In some embodiments, the antibody portion of the ADCs of the present disclosure is an antibody of IgG (e.g., IgGl, IgG2, IgG3, or IgG4) isotype. In some embodiments, the antibody portion of the ADCs of the present disclosure comprises all or a portion of the constant region of an IgG immunoglobulin.

[0183] The antibody portion of the ADCs of the present disclosure can be in the form of an antibody fragment or comprise an antibody fragment. For example, antibodies include llama single domain antibody fragment VHH, and monospecific, bispecific and multispecific fusion proteins thereof with the Fc domain of any class (e.g., IgG, IgE, IgM, IgD and IgA), type (e.g., IgGl, IgG2, IgG3, IgG4, IgAl and IgA2) or subtype of human antibody.

[0184] The antibody portion of the ADCs of the present disclosure can be a functionally active fragment, derivative or analog of an antibody that immunospecifically binds to a target cell (e.g., a cancer cell antigen, an immune cell antigen, a viral antigen or a microbial antigen). In this regard, "functionally active" means that the fragment, derivative or analog is capable of immunospecifically binding to the target cell.

[0185] Useful antibody fragments include, but are not limited to, F(ab')2 fragments, Fab fragments, Fvs, VHH fragments, single-chain antibodies, diabodies, triabodies, tetrabodies, scFv, scFv-FV, or any other molecule having the same specificity as an antibody. The fragments can be obtained by molecular engineering or by chemical or enzymatic treatment of whole antibodies or antibody chains or by recombinant means.

[0186] Useful modified antibody analogs and derivatives include, for example, but are not limited to, derivatives and analogs of antibodies obtained by glycosylation, acetylation, pegylation, phosphorylation, amidation, derivatization by known protecting / blocking groups, proteolytic cleavage, attachment to a cell antibody unit or other protein, etc. Any of a wide variety of chemical modifications can be introduced into the antibody by known techniques, including, but not limited to, specific chemical cleavage, acetylation, formylation, metabolic synthesis in the presence of tunicamycin, etc.

[0187] Target antigens and antibodies

[0188] The antibody portion of the ADCs of the present disclosure can be targeted to any suitable target molecule presented on the surface of a target cell, e.g., a polypeptide, protein, polysaccharide, or lipid molecule. The binding of the antibody to the target molecule should be highly specific to ensure that the ADC specifically binds on the target cell, reducing off-target toxicity. In some embodiments, the binding affinity of the antibody to the target molecule can be selected to be at the nanomolar or sub-nanomolar level.

[0189] Suitable target antigens can be selected by searching for cell surface proteins that are highly expressed in tumors but are lowly expressed or even barely expressed in non-malignant tissues. In some embodiments, such target molecules are membrane antigens that are expressed on the surface of target tumor cells, e.g., tumor-specific antigens or tumor-associated antigens, including blood-borne tumors and solid tumors, including primary and metastatic tumors. In particularly preferred embodiments, the antibodies or antigen-binding fragments in the ADCs of the present disclosure specifically bind one or more tumor-specific antigens or tumor-associated antigens, or immune cell-associated antigens.

[0190] In some embodiments, the tumor-specific or tumor-associated antigen targeted by the ADC antibody moiety of the present disclosure is selected from the group consisting of: HER2, Her3, HER1 (ErbBl), HER4 (ErbB4), TROP2, Nectin4, Tissue Factor, PD-L1, PD-1, PD-L1 / PD-L2, MET, CLDN18.2, KIT, CTLA-4, RPR1, Adrenoreceptor A2 (EphA2), Folate Receptor a (FRa), Mesothelin, Endothelin Receptor, GCPII, IL-13Ra, BCMA, GD2, CLL-1, CA-IX, MUC1, 5T4, AOC3, ALK, AXL, C242, CA-125, CCL11, CCR5, CD2, CD3, CD4, CDS, CD15, CA15-3, CD16, CD18, CD19, CD20, CD21, CD22, CD25, CD30, CD32, CD33, CD37, CD38, CD44, CD52, CD56, CD64, CD66e, CD70, CD72, CD74, CD79a, CD79b, CD123, CD138, CD142, CD174, CD276, CDH3, CDH6, CDH17, CCD79b, CLDN9 / CLDN6, CA19-9, DPEP3, AGS-16, IGF1R, IGF2R, VEGFR1, VEGFR2, VEGFR3, PDGFR-a, PDGFR-b, EGFR, EGFRvIII, ENPP3, FcRH5, FRa, KAAG1, LIV-1, Mesothelin, cMet, ROR1, SLTRK6, TF, BMPR1B, E16, TOP1, STEAP1, Steap2, 0772P, MUC16, Napi2b, Napi3b, Sema 5b, PSCAhlg, ETBR, RNF124, prostate cancer associated gene 1, TrpM4, teratocarcinoma-derived growth factor 1, C3DR, FcRH2, NCA, MDP, IL20R-alpha, Brevican, EphB2R, ASLG659, prostate stem cell antigen precursor, GEDA, BAFF-R, CXCR5, CCR2, CCR8, HLA-DOB, P2X5, LY64, FcRH1, IRTA2, TENB2, integrin alpha 5 beta 6, integrin alpha 4 beta 7, FGF2, FGFR1, FGFR2, FGFR3, FGFR4, PSMA, Somatostatin receptor, RANK, SLAMF7, ITGB6, CEACAM5, CA9, EGFRvlll, IL2RA, AXL receptor tyrosine kinase, TGF-beta R, TNFRSF8, cancer / testis associated antigen, CLEC14A, GRP78, stem cell specific antigen, ASG-5, PRR4, GUCY2C, SLC39A6, TPBG, midkine, HAVCR1, prostate tumor target Mindin, VTCN1, PTK7 protein tyrosine kinase 7, macrophage stimulating 1 receptor, TACSTD2, CA6, DLL3, DLL4, EpCAM, FAP, Fibronectin-EDB, DKK-1, Endoglin, VCAM1, GPC3, DR5, ASCT2, B7H1, B7H3, B7H4.

[0191] In some embodiments, the tumor specific antigen or tumor associated antigen is selected from AXL, B7H1, B7H3, B7H4, BCMA, CD16, CD19, CD22, CD25, CD30, CD32, CD33, CD44, CD64, CD70, CD74, CD79, CD138, CD142, CD276, CDH3, CEACAM5, Claudin 18.2, CLDN9 / CLDN6, DPEP3, EGFR, ENPP3, EphA, FcRH5, FOLR1, FR alpha, GCPII, HER2, HER3, KAAG1, KIT, LIV-1, Mesothelin, cMet, MUC1, NECTIN4, PD-L1, PD-L1 / PD-L2, PSMA, ROR1, RPR1, TF, TOP1, TROP2.

[0192] In some embodiments, the tumor-associated antigen is selected from the group consisting of KIT, FOLR1, CD276, PD-L1, NECTIN4, Mesothelin, MUC1, GCPII, BCMA, cMet, RPR1, CD22, CD19, TOP1, Claudin 18.2, EGFR, TROP2 and HER2. Corresponding antibodies are commercially available or can be produced by techniques known in the art, such as hybridoma technology, recombinant technology, phage display technology, transgenic animals or combinations thereof.

[0193] In preferred embodiments, the antibodies are those binding to antigens preferentially expressed or overexpressed in cancer cells, such as HER2 (ErbB2), PD-1, PD-L1, EGFR, TROP2, Claudin 18.2, EphA-2 and Met, further preferred are HER2 (ErbB2), EGFR, TROP2 and Claudin 18.2.

[0194] The ADC compounds of the present disclosure can treat tumors associated with the expression of the above-mentioned antigens, a specific list of tumors being known or determinable by the skilled person based on the prior art.

[0195] Antibodies immunospecific for tumor-associated antigens are commercially available or can be produced by any method known to the skilled person, such as recombinant expression technology. Nucleotide sequences encoding antibodies immunospecific for cancer cell antigens can be obtained, for example, from the GenBank database or similar databases, from literature publications or by routine cloning and sequencing.

[0196] Antibodies suitable for use in the ADCs of the present disclosure include, but are not limited to: abagovomab, abatacept acasunlimab, abciximab adalimumab adebrelimab, adecatumumab, alacizumab, alemtuzumab altumomab, amivantamab, afelimomab, amostomig, anatumomab, anbenitamab, anetumumab, anvatabart, anrukizumab, apolizumab, arcitumomab, aselizumab, atezolizumab, atlizumab, atorolimumab, avelumab, azertumig, azirkitug, bapineuzumab, barecetamab, basiliximab bavituximab, becotatug, bectumomab belimumab benmelstobart, bertilimumab, betifisolimab, besilesomab, bevacizumab blinatumomab, biciromab, bintrafusp, brallobarbital, brentuximab, bivatuzumab, cafelkibart, calotatug, camidanlumab, cantuzumab, canakinumab (ACZ885), cantuzumab, capromab catumaxomab caxmotabart, cedelizumab cemavafusp, certolizumab, cetuximab ciletatug, citatuzumab, clenoliximab, clivatuzumab, conatumumab, coprelotamab, cosibelimab, dacetuzumab, dacliximab, daclizumab danburstotug, daratumumab, datopotamab, demupitamab, denikitug, denosumab (AMG162), depatuxizumab, detumomab, disitamab, dorlimomab, dorlixizumab, duligotuzumab, duntumumab, durimulumab, durmulumab, durvalumab, edrecolomab, ecromeximab, eculizumab edobacomab, edrecolomab (Mabl7-lA, ), efalizumab efungumab elgemtumab, elotuxumab, elsilimomab, emfizatamab2, enlimomab, enoblituzumab, enristomig, enzelkitug, envafolimab, epitumomab cituxetan, efalizumab, epitumomab, epratuzumab, erfonrilimab, erlizumab, ertumaxomab etanercept etevritamab, etaracizumab (etaratuzumab, ), exbivirumab, fanolesomab faralimomab, farletuzumab, felvizumab, figitumumab, fontolizumab futuximab, galiximab, gantenerumab, gavilimomab garetatug,garivulimab,gemtuzumab,givastomig,gresonitamab,glembatumumab,golimumab(CNTO148),gomiliximab,ibalizumab(TNX-355),ibritumomab,ifinatamab,igovomab,intetumumab,imgatuzumab,imciromab,imneskibart,imzokitug,infliximab inolimomab,inotuzumab,ipilimumab(MDX-010,MDX-101),istiratumab,iratumumab,itanistomig,izalontamab,keliximab,laprituximab,labetuzumab,lanerkitug,lemalesomab,lebrilizumab,lesabelimab,lerdelimumab,lexatumumab(HGS-ETR2,ETR2-ST01),lexitumumab,libivirumab,lintuzumab,lodapolimab,losatuxizumab,lucatumumab,lumiliximab,lumretuzumab,manelimab,mapatumumab(HGSETRl,TRM-1),marlotamig,margetuximab,marstacimab,matuzumab,maslimomab,matuzumab(EMD72000),mepolizumab metelimumab,milatuzumab,minretumomab,mirzotamab,mitumomab,modotuximab,morolimumab,motavizwnab nacolomab,nebratamig1,naptumomab,natalizumab nebacumab,necitumumab,nerelimomab,nezutatug,nimotuzumab(THERACIM THERA- ), nofetumomab,bintunzumab,obrindatamab, ocrelizumab, odulimomab,ofatumumab, olaratumab,omalizumab omburtamab, omectatug, oregovomab osemitamab, opamistomig, opucolimab, oportuzumab, otelixizumab, pacmilimab, pagibaximab, palivizumab Pamvatamig, panitumumab(ABX-EGF, ), panitumumab,pascolizumab, patritumab, pemtumab pertuzumab(2C4, ), petosemtamab, pexelizumab, pimurutamab, pintumomab, priliximab, pritumumab, pumitamig2, ragistomig, ranibizumab raxibacumab, regavirumab, reozalimab, retlirafusp, reslizumab, rilotumab, rituximab robatumumab, rovalpituzumab, rovelizumab, ruplizumab, ruzaltatug, safimestomig, sacituzumab (IMMU-132), satumomab, sevirumab, serclutamab, seribantumab, sibrotuzumab, si mlukafusp, simridarlimab, splizumab (MEDI-507), socazolimab, solabafusp, sonestatug, sontuzumab, spevatamig, stamulumab (MY0-029), sudubrilimab, sugemalimab, sulesomab tacatuzumab, tadocizumab, tagitanlimab, talizumab, taplitumomab, tecotabart, tenatumomab, tefibazumab telimomab, teneliximab, teplizumab, ticilimumab, tigatuzumab, timigutuzumab, tizetatug, tocilizumab tomuzotuximab, toralizumab, tositumomab, trastuzumab tremelimumab, tositumomab, tucotuzumab, tuvirumab, umizortamig2, urtoxazumab, ustekinumab (CNTO 1275), vapaliximab, veltuzumab, vepalimomab, vobramitamab, volociximab, vopikitug, votumumab xirestomig, zalutumumab, zanolimumab (HuMAX-CD4), zanidatamab, zenocutuzumab, ziralimumab, zolbetuximab, zolimomab

[0197] Ab unit targeting HER2

[0198] In a particularly preferred embodiment, the ADCs provided herein comprise an antibody or antigen-binding fragment that specifically binds to human HER2 (anti-HER2 antibody), i.e., the antibody moiety specifically targets the tumor-associated antigen HER2. Accordingly, in some aspects, the disclosure provides an ADC comprising an antibody or antigen-binding fragment thereof that specifically binds to HER2 as the Ab unit of the ADC.

[0199] HER2 is a receptor tyrosine-protein kinase ErbB2, overexpression or gene amplification of HER2 is present in about 20-30% of breast cancers. The increased activation of HER2 triggers multiple downstream pathways, leading to abnormal proliferation of cancer cells (Treish I, Schwartz R, Lindley C: Pharmacology and therapeutic use of trastuzumab in breast cancer. Am J Health Syst Pharm. 2000, 57(22), 2063-76, quiz 2077-9). HER2 is also overexpressed in many other types of cancer, such as gastric cancer, esophageal cancer, colon cancer, rectal cancer, breast cancer, ovarian cancer, cervical cancer, uterine cancer, endometrial cancer, bladder cancer, pancreatic cancer, lung cancer, prostate cancer, osteosarcoma, neuroblastoma or head and neck cancer.

[0200] In some embodiments, the antibody or antibody fragment (e.g. antigen binding fragment) thereof that specifically binds to human HER2 can be selected from trastuzumab, pertuzumab, margetuximab or HT-19, or an antibody fragment thereof or a site-specific mutant thereof, or other anti-human HER2 antibodies that recognize the same epitope or competitively bind to human HER2.

[0201] Trastuzumab (trade name Herceptin or Herclon) is an anti-human epidermal growth factor 2 humanized monoclonal antibody for the treatment of HER2-positive breast cancer, gastrointestinal cancer and gastric cancer. It binds to the membrane proximal portion of the extracellular domain of the HER2 receptor, the amino acid sequences of the heavy and light chain variable regions are described in US Patent 5,821,337, which interact with the 3 loop regions formed by human HER2 residues 557-561, 570-573 and 593-603 (Cho et al., Nature 2003, 421, 756-760), possibly by preventing HER2 receptor dimerization, promoting HER2 receptor endocytosis destruction, inhibiting shedding of the extracellular domain to interfere with HER2 signaling (Hudis CA, N Engl J Med. 2007, 357(1), 39-51). Another important mechanism of action of anti-HER2 antibodies is the mediation of antibody-dependent cellular cytotoxicity (ADCC). In ADCC, the anti-HER2 antibody binds to tumor cells and then recruits immune cells, such as macrophages, through Fc epsilon receptor (Fc epsilon R) interaction. Trastuzumab was approved by the US FDA in September 1998 for the treatment of metastatic breast cancer in patients.

[0202] Pertuzumab (also known as 2C4, Omnitarg, Perjeta) is a humanized monoclonal antibody that binds to the extracellular domain of the HER2 receptor and inhibits dimerization of HER2 with other HER receptors, the amino acid sequences of its heavy and light chains are described in U.S. Patent 7,560,111. Pertuzumab interacts primarily with residues within the 245-333 region of human HER2, particularly residues His 245, Val 286, Ser 288, Leu 295, His 296, or Lys 311 (Franklin et al., Cancer Cell 2004, 5, 317-328). Pertuzumab has been shown to be more effective than trastuzumab in disrupting HER1-HER2 and HER3-HER2 complex formation in breast and prostate cancer cell lines (Agus et al., J Clin Oncol. 2005, 23(11), 2534-43.). Pertuzumab does not require antibody-dependent cellular cytotoxicity for potency, as the intact Fc region is not required for its activity (Agus et al., J Clin Oncol. 2005, 23(11), 2534-43.). Pertuzumab is approved by the U.S. FDA in combination with trastuzumab and docetaxel for the treatment of patients with HER2-positive metastatic breast cancer.

[0203] Margetuximab (also known as MGAH22) is another anti-HER2 monoclonal antibody (see http: / / www.macrogenics.com / products-margetuximab.html). The Fc region of margetuximab is optimized such that its binding to activating FcεRs is increased. Margetuximab is currently in clinical trials for the treatment of patients with relapsed or refractory advanced breast cancer whose tumors are found to express HER2 at a level of 2+ by immunohistochemistry and lack evidence of amplification of the HER2 gene by FISH.

[0204] HT-19 is another anti-HER2 monoclonal antibody that binds to an epitope in human HER2 that is different from that of trastuzumab or pertuzumab, and it has been demonstrated to inhibit HER2 signaling nearly as well as trastuzumab, and to promote HER2 degradation in combination with trastuzumab and pertuzumab (Bergstrom D. A. et al., Cancer Res. 2015, 75, LB-231).

[0205] Exemplary antibodies targeting HER2 that can be used in the ADCs of the present disclosure can be antibodies or antigen-binding fragments comprising all 6 CDR sequences (preferably comprising the heavy chain variable region and light chain variable region sequences) of an antibody selected from the group consisting of: trastuzumab (Herceptin, Genentech, US 6,054,297); ATCC Accession Nos. PTA-10355, PTA-10356, PTA-10357, PTA 10358 (US20100119511); ATCC Accession Nos. CRL-10463 (Genentech); ATCC Accession Nos. HB-12215, HB-12216, CRL 10463, HB-12697; pertuzumab (Omnitarg®, Pertuzumab, Genentech, US20110117097); ATCC Accession Nos. HB-12215, HB-12216, CRL 10463, HB-12698 (US20090202546); ATCC Accession Nos. HB-12215, HB-12216 (US20060088523); ATCC Accession Nos. (7C2) HB-12215, (7F3) HB-12216, (4D5) CRL-10463, (2C4) HB-12697 (US20060018899); TrasGEX (Glycotope: http: / / www.glycotope.com / pipeline). The present disclosure also contemplates the anti-HER2 antibodies disclosed in US20110177095, US20100119511, US20110117097, US20090285837, US20090202546, US20060088523, US20060018899, US2011 / 0159014, US20090187007, US20110217305.

[0206] > Trastuzumab heavy chain amino acid sequence (SEQ ID NO: 2)

[0207] > Trastuzumab heavy chain amino acid sequence (SEQ ID NO: 2)

[0208] > Trastuzumab heavy chain amino acid sequence (SEQ ID NO: 2)

[0209] > Trastuzumab heavy chain amino acid sequence (SEQ ID NO: 2)

[0210] > Trastuzumab light chain LCDR3 sequence (SEQ ID NO: 5)

[0211] > Trastuzumab heavy chain HCDR1 sequence (SEQ ID NO: 6)

[0212] > Trastuzumab heavy chain HCDR2 sequence (SEQ ID NO: 7)

[0213] > Trastuzumab heavy chain HCDR3 sequence (SEQ ID NO: 8)

[0214] > Trastuzumab light chain variable region VL (SEQ ID NO: 9)

[0215] > Trastuzumab heavy chain variable region VH (SEQ ID NO: 10)

[0216] In one embodiment, the antibody moiety for the ADC of the disclosure comprises all 6 CDR sequences of trastuzumab. In another embodiment, the antibody moiety for the ADC of the disclosure comprises the heavy chain variable region sequence and the light chain variable region sequence of trastuzumab. In yet another embodiment, the antibody moiety for the ADC of the disclosure comprises the heavy chain sequence and the light chain sequence of trastuzumab.

[0217] In some embodiments, the Ab unit of the ADC of the disclosure comprises three CDRs of the heavy chain variable region (VH) sequence of SEQ ID NO: 10 and three CDRs of the light chain variable region (VL) sequence of SEQ ID NO: 9, and preferably, wherein the CDRs are defined according to Kabat or IMGT or a combination thereof.

[0218] In some embodiments, the Ab unit of the ADC of the disclosure comprises 3 heavy chain complementarity determining regions (HCDRs) and 3 light chain complementarity determining regions (LCDRs), wherein:

[0219] According to the Kabat definition, HCDR1 comprises or consists of the amino acid sequence of SEQ ID NO: 6, HCDR2 comprises or consists of the amino acid sequence of SEQ ID NO: 7, HCDR3 comprises or consists of the amino acid sequence of SEQ ID NO: 8, LCDR1 comprises or consists of the amino acid sequence of SEQ ID NO: 3, LCDR2 comprises or consists of the amino acid sequence of SEQ ID NO: 4, and LCDR3 comprises or consists of the amino acid sequence of SEQ ID NO: 5.

[0220] In one embodiment, the Ab unit of the ADC of the present disclosure comprises a heavy chain variable region, wherein the heavy chain variable region comprises: the amino acid sequence set forth in SEQ ID NO: 10, or an amino acid sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity thereto.

[0221] In one embodiment, the Ab unit of the ADC of the present disclosure comprises a light chain variable region, wherein the light chain variable region comprises: the amino acid sequence set forth in SEQ ID NO: 9, or an amino acid sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity thereto.

[0222] In some preferred embodiments, the Ab unit of the ADC of the present disclosure comprises a heavy chain variable region and a light chain variable region, wherein the heavy chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 10, and wherein the light chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 9.

[0223] In some embodiments, the Ab unit of the ADC of the present disclosure preferably further comprises a heavy chain constant region and / or a light chain constant region of an antibody. Preferably, the heavy chain constant region is a heavy chain constant region derived from a human immunoglobulin. Preferably, the light chain constant region is a light chain constant region derived from a human immunoglobulin. In some aspects, the heavy chain constant region comprised in the Ab unit can be of any isotype or subtype, e.g., a heavy chain constant region of an IgGl, IgG2, IgG3, or IgG4 isotype, and preferably an IgGl, IgG2, or IgG4 heavy chain constant region, and in particular a human IgGl heavy chain constant region. In further aspects, the light chain constant region comprised in the Ab unit can be a kappa light chain constant region or a lambda light chain constant region, and in particular a human kappa light chain constant region.

[0224] In some embodiments, the Ab unit of the ADC of the present disclosure comprises a human IgGl heavy chain constant region. Preferably, the heavy chain constant region comprises the amino acid sequence of SEQ ID NO: 11, or an amino acid sequence comprising at least one, two or three, but not more than 20, 10 or 5 amino acid alterations relative to the amino acid sequence of SEQ ID NO: 11, or a sequence having at least 95-99% identity to the amino acid sequence of SEQ ID NO: 11.

[0225] One exemplary amino acid sequence of a human IgGl heavy chain constant region (SEQ ID NO: 11)

[0226] In some embodiments, the Ab unit of the ADC of the present disclosure comprises a human kappa light chain constant region. Preferably, the light chain constant region comprises the amino acid sequence of SEQ ID NO: 12, or an amino acid sequence that comprises at least one, two or three, but not more than 20, 10 or 5 amino acid alterations relative to the amino acid sequence of SEQ ID NO: 12, or a sequence that is at least 95-99% identical to the amino acid sequence of SEQ ID NO: 12.

[0227] One exemplary amino acid sequence of a human kappa light chain constant region (SEQ ID NO: 12)

[0228] In some embodiments, the Ab unit of the ADC of the present disclosure is a full-length antibody comprising a heavy chain constant region and a light chain constant region. In some embodiments, the Ab unit is a tetrameric structure formed by two light chains and two heavy chains. In still other embodiments, the Ab unit is an IgG antibody, in particular an IgGl antibody.

[0229] In some preferred embodiments, the Ab unit of the ADC of the present disclosure comprises a heavy chain and a light chain, wherein: the heavy chain comprises or consists of the amino acid sequence set forth in SEQ ID NO: 2, or an amino acid sequence that has at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% sequence identity thereto. In other preferred embodiments, the Ab unit of the ADC of the present disclosure comprises a heavy chain and a light chain, wherein: the light chain comprises or consists of the amino acid sequence set forth in SEQ ID NO: 1, or an amino acid sequence that has at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% sequence identity thereto.

[0230] In some more preferred embodiments, the Ab unit of the ADC of the present disclosure comprises:

[0231] (a) a heavy chain comprising the amino acid sequence of SEQ ID NO: 2, and

[0232] (b) a light chain comprising the amino acid sequence of SEQ ID NO: 1.

[0233] Ab units targeting TROP2

[0234] In a particularly preferred embodiment, the ADC provided herein comprises an antibody or antigen binding fragment that specifically binds to human TROP2 (anti-TROP2 antibody), i.e., the antibody moiety specifically targets the tumor-associated antigen TROP2. Accordingly, in some aspects, the present disclosure provides an ADC comprising an antibody or antigen binding fragment thereof that specifically binds to TROP2 as the Ab unit of the ADC.

[0235] Trophoblast cell surface antigen 2 (TROP2), also known as tumor-associated calcium signal transducer 2 (TACSTD2), is a type I transmembrane cell surface glycoprotein. The sequence of human TROP2 is available from UniProtKB Accession No. P09758. It has been demonstrated that TROP2 is overexpressed in many solid tumors, including, but not limited to, various human epithelial cancers, such as cervical cancer, endometrial cancer, breast cancer, urothelial cancer, lung cancer, gastric cancer, prostate cancer, colorectal cancer, and pancreatic cancer. Moreover, TROP2 can play a role in the proliferation, invasion, migration, apoptosis, and treatment resistance of tumor cells through binding or interacting with various molecules. These features have made TROP2 an attractive pan-cancer target for cancer treatment. Ying Wen et al., A literature review of the promising future of TROP2: a potential drug therapy target, Ann Transl Med. 2022, 10(24), 1403, doi:10.21037 / atm-22-5976.

[0236] Antibodies targeting human TROP2 that can be used in the ADCs of the present disclosure can be prepared using antibody preparation processes known in the art. For example, anti-TROP2 antibodies can be obtained by immunizing an animal with human TROP2 (UniProtKB Accession No. P09758) or a polypeptide comprising the amino acid sequence of the extracellular domain of TROP2, harvesting antibodies from the immunized animal, and purifying and preferably humanizing the antibodies. In addition, a completely human sequence anti-human TROP2 antibody can be obtained using a yeast display library expressing human immunoglobulin sequences or a transgenic animal, etc.

[0237] In some embodiments, the antibody or antibody fragment (e.g., antigen binding fragment) that specifically binds to human TROP2 can be selected from Sacituzumab, Datopotamab, or an antibody fragment thereof, or other anti-human TROP2 antibodies that recognize the same epitope or competitively bind to human TROP2.

[0238] Sacituzumab, also known as sacituzumab govitecan, is a humanized form of the murine monoclonal antibody RS7 developed by Immunomedics, and is a humanized IgGl kappa monoclonal antibody targeting TROP2. The antibody is able to bind directly to cancer cells expressing TROP2 and triggers antibody endocytosis. The sequence of sacituzumab can be found in US10179171B2.

[0239] Datopotamab is an IgGl type anti-TROP2 antibody. The antibody was generated by humanization of a mouse mAb that specifically binds to human TROP2. The sequence of datopotamab can be found in Daisuke Okajima et al., Datopotamab Deruxtecan, a Novel TROP2-directed Antibody-drug Conjugate, Demonstrates Potent Antitumor Activity by Efficient Drug Delivery to Tumor Cells, Mol Cancer Ther 2021 20(12), 2329-2340.

[0240] Exemplary antibodies targeting human TROP2 that can be used in the ADCs of the present disclosure can be antibodies or antigen-binding fragments comprising all 6 CDR sequences of an antibody selected from the group consisting of: sacituzumab and datopotamab (preferably, comprising the heavy chain variable region and light chain variable region sequences of an antibody selected from the group consisting of: sacituzumab and datopotamab). The present disclosure also contemplates anti-human TROP2 antibodies disclosed in WO2010089782A1; US2021 / 0393792A1; WO2008 / 144891, WO2011 / 145744, WO2011 / 155579, WO2013 / 077458, WO2003 / 074566, WO2011 / 068845, WO2013 / 068946, US2023 / 0270870A1.

[0241] > Sacituzumab heavy chain amino acid sequence (SEQ ID NO: 14)

[0242] > Sacituzumab heavy chain amino acid sequence (SEQ ID NO: 14)

[0243] > Sacituzumab heavy chain amino acid sequence (SEQ ID NO: 14)

[0244] Sacituzumab heavy chain HCDR1 sequence (SEQ ID NO: 18)

[0245] Sacituzumab heavy chain HCDR2 sequence (SEQ ID NO: 19)

[0246] Sacituzumab heavy chain HCDR3 sequence (SEQ ID NO: 20)

[0247] Sacituzumab heavy chain HCDR2 sequence (SEQ ID NO: 19)

[0248] Sacituzumab heavy chain HCDR3 sequence (SEQ ID NO: 20)

[0249] Sacituzumab heavy chain HCDR2 sequence (SEQ ID NO: 19)

[0250] Sacituzumab heavy chain HCDR3 sequence (SEQ ID NO: 20)

[0251] In one embodiment, the antibody moiety for the ADC of the disclosure comprises all 6 CDR sequences of Sacituzumab or Datopotamab. In another embodiment, the antibody moiety for the ADC of the disclosure comprises the heavy chain variable region sequence and the light chain variable region sequence of Sacituzumab or Datopotamab. In yet another embodiment, the antibody moiety for the ADC of the disclosure comprises the heavy chain sequence and the light chain sequence of Sacituzumab or Datopotamab.

[0252] In some embodiments, the Ab unit of the ADC of the disclosure comprises three CDRs of the heavy chain variable region (VH) sequence of SEQ ID NO: 22 and three CDRs of the light chain variable region (VL) sequence of SEQ ID NO: 21, and preferably, wherein the CDRs are defined according to Kabat or IMGT or a combination thereof.

[0253] In some embodiments, the Ab unit of the ADC of the disclosure comprises 3 heavy chain complementarity determining regions (HCDRs) and 3 light chain complementarity determining regions (LCDRs), wherein:

[0254] According to the Kabat definition, HCDR1 comprises or consists of the amino acid sequence of SEQ ID NO: 18, HCDR2 comprises or consists of the amino acid sequence of SEQ ID NO: 19, HCDR3 comprises or consists of the amino acid sequence of SEQ ID NO: 20, LCDR1 comprises or consists of the amino acid sequence of SEQ ID NO: 15, LCDR2 comprises or consists of the amino acid sequence of SEQ ID NO: 16, and LCDR3 comprises or consists of the amino acid sequence of SEQ ID NO: 17.

[0255] In one embodiment, the Ab unit of the ADC of the present disclosure comprises a heavy chain variable region, wherein the heavy chain variable region comprises: the amino acid sequence set forth in SEQ ID NO: 22, or an amino acid sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity thereto.

[0256] In one embodiment, the Ab unit of the ADC of the present disclosure comprises a light chain variable region, wherein the light chain variable region comprises: the amino acid sequence set forth in SEQ ID NO: 21, or an amino acid sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity thereto.

[0257] In some preferred embodiments, the Ab unit of the ADC of the present disclosure comprises a heavy chain variable region and a light chain variable region, wherein the heavy chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 22, and wherein the light chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 21.

[0258] In some embodiments, the Ab unit of the ADC of the present disclosure preferably further comprises a heavy chain constant region and / or a light chain constant region of an antibody. Preferably, the heavy chain constant region is a heavy chain constant region derived from a human immunoglobulin. Preferably, the light chain constant region is a light chain constant region derived from a human immunoglobulin. In some aspects, the heavy chain constant region comprised in the Ab unit can be of any isotype or subtype, e.g., a heavy chain constant region of an IgGl, IgG2, IgG3, or IgG4 isotype, and preferably an IgGl, IgG2, or IgG4 heavy chain constant region, in particular a human IgGl heavy chain constant region. In further aspects, the light chain constant region comprised in the Ab unit can be a kappa light chain constant region or a lambda light chain constant region, in particular a human kappa light chain constant region.

[0259] In some embodiments, the Ab unit of the ADC of the present disclosure comprises a human IgGl heavy chain constant region. Preferably, the heavy chain constant region comprises the amino acid sequence of SEQ ID NO: 23, or an amino acid sequence that comprises at least one, two or three, but not more than 20, 10 or 5 amino acid alterations with respect to the amino acid sequence of SEQ ID NO: 23, or a sequence that is at least 95-99% identical to the amino acid sequence of SEQ ID NO: 23.

[0260] One exemplary amino acid sequence of a human IgGl heavy chain constant region (SEQ ID NO: 23)

[0261] In some embodiments, the Ab unit of the ADC of the present disclosure comprises a human kappa light chain constant region. Preferably, the light chain constant region comprises the amino acid sequence of SEQ ID NO: 12, or an amino acid sequence that comprises at least one, two or three, but not more than 20, 10 or 5 amino acid alterations with respect to the amino acid sequence of SEQ ID NO: 12, or a sequence that is at least 95-99% identical to the amino acid sequence of SEQ ID NO: 12.

[0262] In some embodiments, the Ab unit of the ADC of the present disclosure is a full-length antibody comprising a heavy chain constant region and a light chain constant region. In some embodiments, the Ab unit is a tetrameric structure having two light chains and two heavy chains. In still other embodiments, the Ab unit is an IgG antibody, in particular an IgGl antibody.

[0263] In some preferred embodiments, the Ab unit of the ADC of the present disclosure comprises a heavy chain and a light chain, wherein: the heavy chain comprises or consists of the amino acid sequence set forth in SEQ ID NO: 14, or an amino acid sequence that has at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% sequence identity thereto. In other preferred embodiments, the Ab unit of the ADC of the present disclosure comprises a heavy chain and a light chain, wherein: the light chain comprises or consists of the amino acid sequence set forth in SEQ ID NO: 13, or an amino acid sequence that has at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% sequence identity thereto.

[0264] In some more preferred embodiments, the Ab unit of the ADC of the present disclosure comprises:

[0265] (c) a heavy chain comprising the amino acid sequence of SEQ ID NO: 14, and

[0266] (d) a light chain comprising the amino acid sequence of SEQ ID NO: 13. In some embodiments, the Ab unit of the ADC of the present disclosure comprises a human IgGl heavy chain constant region. Preferably, the heavy chain constant region comprises the amino acid sequence of SEQ ID NO: 23, or an amino acid sequence that comprises at least one, two or three, but not more than 20, 10 or 5 amino acid alterations with respect to the amino acid sequence of SEQ ID NO: 23, or a sequence that is at least 95-99% identical to the amino acid sequence of SEQ ID NO: 23.

[0260] One exemplary amino acid sequence of a human IgGl heavy chain constant region (SEQ ID NO: 23)

[0261] In some embodiments, the Ab unit of the ADC of the present disclosure comprises a human kappa light chain constant region. Preferably, the light chain constant region comprises the amino acid sequence of SEQ ID NO: 12, or an amino acid sequence that comprises at least one, two or three, but not more than 20, 10 or 5 amino acid alterations with respect to the amino acid sequence of SEQ ID NO: 12, or a sequence that is at least 95-99% identical to the amino acid sequence of SEQ ID NO: 12.

[0262] In some embodiments, the Ab unit of the ADC of the present disclosure is a full-length antibody comprising a heavy chain constant region and a light chain constant region. In some embodiments, the Ab unit is a tetrameric structure having two light chains and two heavy chains. In still other embodiments, the Ab unit is an IgG antibody, in particular an IgGl antibody.

[0263] In some preferred embodiments, the Ab unit of the ADC of the present disclosure comprises a heavy chain and a light chain, wherein: the heavy chain comprises or consists of the amino acid sequence set forth in SEQ ID NO: 14, or an amino acid sequence that has at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% sequence identity thereto. In other preferred embodiments, the Ab unit of the ADC of the present disclosure comprises a heavy chain and a light chain, wherein: the light chain comprises or consists of the amino acid sequence set forth in SEQ ID NO: 13, or an amino acid sequence that has at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% sequence identity thereto.

[0264] In some more preferred embodiments, the Ab unit of the ADC of the present disclosure comprises:

[0265] (c) a heavy chain comprising the amino acid sequence of SEQ ID NO: 14, and

[0266] (d) a light chain comprising the amino acid sequence of SEQ ID NO: 13.

[0267] Cancers that can be treated with the ADCs of the present disclosure targeting TROP2 include, but are not limited to, adenocarcinoma, squamous cell carcinoma, non-small cell lung cancer (NSCLC), small cell lung cancer (SCLC), colorectal cancer, gastric adenocarcinoma, esophageal cancer, hepatocellular carcinoma, ovarian epithelial cancer, breast cancer, metastatic breast cancer, triple-negative breast cancer (TNBC), prostate cancer, hormone-refractory prostate cancer, pancreatic ductal adenocarcinoma, head and neck cancer, renal cell carcinoma, bladder tumor, cervical cancer, endometrial cancer, uterine cancer, follicular thyroid cancer, glioblastoma multiforme.

[0268] Ab unit targeting Claudin 18.2

[0269] In a particularly preferred embodiment, the ADCs provided herein comprise an antibody or antigen-binding fragment that specifically binds human Claudin 18.2 (anti-Claudin 18.2 antibody), i.e., the antibody moiety specifically targets the tumor-associated antigen Claudin 18.2. Accordingly, in some aspects, the disclosure provides an ADC comprising an antibody or antigen-binding fragment thereof that specifically binds Claudin 18.2 as the Ab unit of the ADC.

[0270] Claudin 18.2 (Claudin 18.2, also abbreviated as CLDN18.2) belongs to the Claudin family of tight junction membrane proteins. Human and various mammalian Claudin 18.2 sequences can be found at UniProtKB. For example, the human Claudin 18.2 sequence can be found at UniProtKB accession number P56856-2. The protein is mainly restricted to differentiated gastric mucosal epithelial cells in healthy tissues, but shows aberrant overexpression in a range of malignancies, particularly in digestive system malignancies. Therefore, Claudin 18.2 is proposed as a promising target for the development of antibody-based ADC cancer treatment drugs. Daisuke Kyuno et al., Claudin-18.2 as a therapeutic target in cancers: cumulative findings from basic research and clinical trials, Tissue Barriers. 2022, 10(1), 1967080. doi:10.1080 / 21688370.2021.1967080; Jinxia Chen, Targeting CLDN18.2 in cancers of the gastrointestinal tract: New drugs and new indications, Front Oncol. 2023, 13, 1132319, doi:10.3389 / fonc.2023.1132319.

[0271] Antibodies targeting human Claudin 18.2 that can be used in the ADCs of the present disclosure can be prepared using antibody preparation processes known in the art. For example, anti-Claudin 18.2 antibodies can be obtained by immunizing an animal with human Claudin 18.2 (UniProtKB accession number P56856-2) or a polypeptide comprising the amino acid sequence of the extracellular domain of Claudin 18.2, harvesting antibodies from the immunized animal, and purifying and preferably humanizing. In addition, a yeast display library or transgenic animal expressing human immunoglobulin sequences can be used to obtain fully human sequence anti-human Claudin 18.2 antibodies.

[0272] In some embodiments, the antibody or antibody fragment (e.g., antigen binding fragment) that specifically binds to human Claudin 18.2 can be selected from Zolbetuximab (sotituximab), Osemitamab (TST001), CMG901, ASKB589, ZL-1211, or an antibody fragment thereof, or other anti-human Claudin 18.2 antibody that recognizes the same epitope or competitively binds to human Claudin 18.2.

[0273] Zolbetuximab (also known as GC-182, IMAB-362, IMAB362, claudiximab) is an IgGl antibody derived from a murine monoclonal antibody and has been chimerized to display a human IgGl constant region for clinical use. This antibody is capable of directly binding to cancer cells expressing CLDN18.2 and triggers antibody endocytosis. The sequence of Zolbetuximab can be found in WO2007059997 and WO2016 / 165762.

[0274] Osemitamab (TST001) is a high-affinity humanized anti-Claudin 18.2 antibody. This antibody has enhanced antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) and exhibits strong anti-tumor activity in tumor xenograft models. The sequence of this antibody can be found in Inxight Drugs and INN (code 11927).

[0275] CMG901, ASKB589, ZL-1211 are exemplary antibodies against human CLDN18.2 that are in clinical trials. See DOI: 10.1200 / JCO.2023.41.4_suppl.352; DOI: 10.1200 / JCO.2023.41.4_suppl.397; DOI: 10.1200 / JCO.2023.41.16_suppl.2537.

[0276] Exemplary antibodies targeting human CLDN18.2 that can be used in the ADCs of the present disclosure can be antibodies or antigen binding fragments comprising all 6 CDR sequences (preferably, comprising the heavy chain variable region and light chain variable region sequences) of an antibody selected from the group consisting of Zolbetuximab, Osemitamab (TST001), and CMG901.

[0277] The present disclosure also contemplates anti-human Claudin 18.2 antibodies disclosed in WO2007059997A1, CN107667118A, WO2016 / 166122, US11555070B2, WO2020 / 135674, WO2018 / 006882, CN109762067, WO2019 / 242505, WO2020 / 038404, WO2020 / 043044, WO2020 / 063988, WO2020 / 082209, WO2020 / 018852, WO2020 / 023679, WO2020 / 135674, WO2020 / 135201, WO2020 / 139956, WO2020 / 025792, WO2020160560, CN111808194, and WO2020200196.

[0278] Zolbetuximab heavy chain amino acid sequence (SEQ ID NO: 25)

[0279] Zolbetuximab heavy chain amino acid sequence (SEQ ID NO: 25)

[0280] Zolbetuximab heavy chain amino acid sequence (SEQ ID NO: 25)

[0281] Zolbetuximab heavy chain amino acid sequence (SEQ ID NO: 25)

[0282] Zolbetuximab heavy chain amino acid sequence (SEQ ID NO: 25)

[0283] Zolbetuximab heavy chain amino acid sequence (SEQ ID NO: 25)

[0284] Zolbetuximab heavy chain amino acid sequence (SEQ ID NO: 25)

[0285] Zolbetuximab heavy chain amino acid sequence (SEQ ID NO: 25)

[0286] Zolbetuximab heavy chain amino acid sequence (SEQ ID NO: 25)

[0287] Zolbetuximab heavy chain variable region VH (SEQ ID NO: 33)

[0288] In one embodiment, the antibody moiety for the ADC of the disclosure comprises all 6 CDR sequences of Zolbetuximab. In another embodiment, the antibody moiety for the ADC of the disclosure comprises the heavy chain variable region sequence and the light chain variable region sequence of Zolbetuximab. In yet another embodiment, the antibody moiety for the ADC of the disclosure comprises the heavy chain sequence and the light chain sequence of Zolbetuximab.

[0289] In some embodiments, the Ab unit of the ADC of the disclosure comprises three CDRs of the heavy chain variable region (VH) sequence of SEQ ID NO: 33 and three CDRs of the light chain variable region (VL) sequence of SEQ ID NO: 32, and preferably, wherein the CDRs are defined according to Kabat or IMGT or a combination thereof.

[0290] In some embodiments, the Ab unit of the ADC of the disclosure comprises 3 heavy chain complementarity determining regions (HCDRs) and 3 light chain complementarity determining regions (LCDRs), wherein:

[0291] According to the Kabat definition, HCDR1 comprises or consists of the amino acid sequence of SEQ ID NO: 29, HCDR2 comprises or consists of the amino acid sequence of SEQ ID NO: 30, HCDR3 comprises or consists of the amino acid sequence of SEQ ID NO: 31, LCDR1 comprises or consists of the amino acid sequence of SEQ ID NO: 26, LCDR2 comprises or consists of the amino acid sequence of SEQ ID NO: 27, and LCDR3 comprises or consists of the amino acid sequence of SEQ ID NO: 28.

[0292] In one embodiment, the Ab unit of the ADC of the disclosure comprises a heavy chain variable region, wherein the heavy chain variable region comprises: the amino acid sequence set forth in SEQ ID NO: 33, or an amino acid sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity thereto.

[0293] In one embodiment, the Ab unit of the ADC of the disclosure comprises a light chain variable region, wherein the light chain variable region comprises: the amino acid sequence set forth in SEQ ID NO: 32, or an amino acid sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity thereto.

[0294] In some preferred embodiments, the Ab unit of the ADC of the present disclosure comprises a heavy chain variable region and a light chain variable region, wherein the heavy chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 33, and wherein the light chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 32.

[0295] In some embodiments, the Ab unit of the ADC of the present disclosure preferably further comprises a heavy chain constant region and / or a light chain constant region of an antibody. Preferably, the heavy chain constant region is a heavy chain constant region derived from a human immunoglobulin. Preferably, the light chain constant region is a light chain constant region derived from a human immunoglobulin. In some aspects, the heavy chain constant region comprised in the Ab unit can be of any isotype or subtype, e.g., a heavy chain constant region of an IgGl, IgG2, IgG3 or IgG4 isotype, and preferably an IgGl, IgG2 or IgG4 heavy chain constant region, in particular a human IgGl heavy chain constant region. In further aspects, the light chain constant region comprised in the Ab unit can be a kappa light chain constant region or a lambda light chain constant region, in particular a human kappa light chain constant region.

[0296] In some embodiments, the Ab unit of the ADC of the present disclosure comprises a human IgGl heavy chain constant region. Preferably, the heavy chain constant region comprises the amino acid sequence of SEQ ID NO: 34, or an amino acid sequence comprising at least one, two or three, but not more than 20, 10 or 5 amino acid alterations relative to the amino acid sequence of SEQ ID NO: 34, or a sequence having at least 95-99% identity to the amino acid sequence of SEQ ID NO: 34.

[0297] An exemplary amino acid sequence of a human IgGl heavy chain constant region (SEQ ID NO: 34)

[0298] In some embodiments, the Ab unit of the ADC of the present disclosure comprises a human kappa light chain constant region. Preferably, the light chain constant region comprises the amino acid sequence of SEQ ID NO: 12, or an amino acid sequence comprising at least one, two or three, but not more than 20, 10 or 5 amino acid alterations relative to the amino acid sequence of SEQ ID NO: 12, or a sequence having at least 95-99% identity to the amino acid sequence of SEQ ID NO: 12.

[0299] In some embodiments, the Ab unit of the ADC of the present disclosure is a full-length antibody comprising a heavy chain constant region and a light chain constant region. In some embodiments, the Ab unit is a tetrameric structure formed by two light chains and two heavy chains. In further embodiments, the Ab unit is an IgG antibody, in particular an IgGl antibody.

[0300] In some preferred embodiments, the Ab unit of the ADC of the present disclosure comprises a heavy chain and a light chain, wherein: the heavy chain comprises or consists of the amino acid sequence set forth in SEQ ID NO: 25, or an amino acid sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity thereto. In other preferred embodiments, the Ab unit of the ADC of the present disclosure comprises a heavy chain and a light chain, wherein: the light chain comprises or consists of the amino acid sequence set forth in SEQ ID NO: 24, or an amino acid sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity thereto.

[0301] In some more preferred embodiments, the Ab unit of the ADC of the present disclosure comprises:

[0302] (e) a heavy chain comprising the amino acid sequence of SEQ ID NO: 25, and

[0303] (f) a light chain comprising the amino acid sequence of SEQ ID NO: 24.

[0304] Cancers that can be treated with the Claudin 18.2-targeting ADCs of the present disclosure include, but are not limited to, various digestive tract cancers, such as gastric cancer (GC), gastroesophageal junction (GEJ) cancer, esophageal cancer, and pancreatic cancer.

[0305] Ab units targeting EGFR

[0306] In a particularly preferred embodiment, the ADCs provided herein include an antibody or antigen-binding fragment that specifically binds to human EGFR (anti-EGFR antibody), i.e., the antibody moiety specifically targets the tumor-associated antigen EGFR. Thus, in some aspects, the present disclosure provides an ADC comprising an antibody or antigen-binding fragment thereof that specifically binds to EGFR as the Ab unit of the ADC.

[0307] Epidermal growth factor receptor, also abbreviated herein as EGFR, is one of the members of the epidermal growth factor receptor (HER) family, encoded by the c-erbB proto-oncogene (also known as HER-1 or Erb-B1). EGFR sequences for humans and various mammals thereof can be found at UniProtKB. For example, the human EGFR sequence can be found at UniProtKB Accession No. P00533. EGFR is overexpressed in many solid tumors, including lung cancer, head and neck cancer, breast cancer, kidney cancer, gastric cancer, colon cancer, pancreatic cancer, ovarian cancer, prostate cancer, and bladder cancer; and EGFR can induce tumor proliferation through homo-dimerization.

[0308] EGFR has been proposed as a promising target for antibody-based cancer therapeutics. To date, five EGFR-targeting monoclonal antibodies have been approved for clinical cancer treatment, namely cetuximab, ), panitumumab, ), nimotuzumab, ), necitumumab , and amivantamab (amivantamab-vmjw; ). In addition, three EGFR-based ADC drugs are in clinical trial stage. However, no EGFR-based ADC has been approved for treatment to date. See Jinfeng Yu et al., Antibody-Drug Conjugates Targeting the Human Epidermal Growth Factor Receptor Family in Cancers, Front Mol Biosci. 2022, 9, 847835, doi: 10.3389 / fmolb.2022.847835.

[0309] A variety of anti-EGFR monoclonal antibodies have been developed for binding to the extracellular domain of the receptor to block the interaction of the receptor with ligands or its dimerization. These antibodies can all be suitable for use in the present disclosure. In addition, antibodies targeting human EGFR for use in the ADCs of the present disclosure can also be prepared using antibody preparation processes known in the art. For example, anti-EGFR antibodies can be obtained by immunizing an animal with human EGFR (UniProtKB Accession No. P00533) or a polypeptide comprising the amino acid sequence of the extracellular domain of EGFR, harvesting antibodies from the immunized animal, and purifying and preferably humanizing. In addition, yeast display libraries expressing human immunoglobulin sequences or transgenic animals can be used to obtain fully human sequence antibodies against human EGFR.

[0310] The antibodies targeting human EGFR for use in the ADCs of the present disclosure can be monospecific antibodies that bind EGFR. In some cases, the antibodies targeting human EGFR for use in the ADCs of the present disclosure can also be multispecific antibodies, especially bispecific antibodies, such as bispecific antibodies targeting EGFR and MET; or bispecific antibodies targeting MUC1 and EGFR; or bispecific antibodies targeting Her3 and EGFR.

[0311] In some embodiments, the anti-human EGFR antibodies or antibody fragments (e.g., antigen-binding fragments) thereof for use in the ADCs of the present disclosure can be selected from cetuximab ( ) panitumumab, ) nimotuzumab, ) necitumumab ) amivantamab (amivantamab-vmjw; ) depatuxizumab (ABT-806), NECITUMUMAB, IZALONTAMAB, BAFISONTAMAB, Petosemtamab, PIMURUTAMAB, FUTUXIMAB, MODOTUXIMAB (Zatuximab), or an antibody fragment thereof, or other anti-human EGFR antibodies that recognize the same epitope or compete for binding to human EGFR. Sequences of the above antibodies can be found in Inxight Drugs and International Nonproprietary Names (INN) codes 7906, 8499, 8545, 9083, 11030, 10263, 9083, 12022, 11851, 11136, 11309, 9612, and 9613.

[0312] ) cetuximab, ) is a recombinant chimeric human / murine IgGl monoclonal antibody. This antibody binds to the extracellular domain of non-activated EGFR with much higher affinity than the endogenous ligand, can competitively block the binding of the ligand to the receptor, block the agonistic effect of the ligand on the receptor, and can induce endocytosis of EGFR, down-regulate the expression level of EGFR on the cell membrane. In addition, the antibody can activate antibody-dependent cell-mediated cytotoxicity (ADCC), producing further cell-killing effects. The sequence of cetuximab can be found in WO2007092453 and INN code 7906.

[0313] ) panitumumab, ) is a recombinant humanized IgG2 monoclonal antibody. Panitumumab specifically binds to EGFR on tumor cells and competitively inhibits the binding of EGFR ligands. Preclinical studies have shown that the binding of panitumumab to EGFR can prevent ligand-induced receptor autophosphorylation and activation of receptor-associated kinases, thereby inhibiting cell growth, inducing apoptosis, reducing the production of pro-inflammatory cytokines and vascular growth factors, and can induce EGFR internalization. The sequence of panitumumab can be found in INN code 8499.

[0314] Amivantamab (also known as JNJ-61186372) is an anti-EGFR-MET bispecific antibody derived from Chinese hamster ovary cells approved for the treatment of adult patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) harboring epidermal growth. The antibody binds to EGFR and MET and blocks the binding of the receptors to their ligands and induces internalization of EGFR and MET at the cell surface. Amivantamab can significantly downregulate the expression of EGFR and MET at the surface of NSCLC cells, further reducing downstream signaling. The sequence of amivantamab can be found in INN code 9083.

[0315] Exemplary antibodies targeting human EGFR that can be used in the ADCs of the present disclosure can be antibodies or antigen-binding fragments comprising all 6 CDR sequences of an antibody selected from the group consisting of cetuximab, panitumumab, nimotuzumab, necitumuma, amivantamab, depatuxizumab, NECITUMUMAB, IZALONTAMAB, BAFISONTAMAB, Petosemtamab, PIMURUTAMAB, FUTUXIMAB, and MODOTUXIMAB, preferably comprising the heavy chain variable region and light chain variable region sequences of an antibody selected from the group consisting of cetuximab, panitumumab, nimotuzumab, necitumuma, amivantamab, depatuxizumab, NECITUMUMAB, IZALONTAMAB, BAFISONTAMAB, Petosemtamab, PIMURUTAMAB, FUTUXIMAB, and MODOTUXIMAB.

[0316] The present disclosure also contemplates anti-human EGFR antibodies disclosed in WO2023040941A1, WO2022271722A1, WO2022159576A1, WO2022128716A1, WO2022105878A1, WO2021247798A1, WO2022104697A1, WO2021066869A1, WO2020233534A1, WO2020130125A1, WO2019046858A1, WO2019046859A1, WO2019035630A2, WO2019035630A3, WO2018098035A1, WO2017214233A1, WO2017214282A1, WO2017214301A1, WO2017161206A1, WO2017139623A1, WO2017136581A1, WO2017076492A1, WO2017060322A3, WO2017025458A1, WO2017008169A1, WO2016065456A1, WO2015143382A1, WO2014143765A1, WO2014143765A8, WO2014152199A1, WO2014094355A1, WO2012143495A2, and WO2012143495A3.

[0317] Cetuximab heavy chain amino acid sequence (SEQ ID NO: 36)

[0318] Cetuximab heavy chain amino acid sequence (SEQ ID NO: 36)

[0319] Cetuximab heavy chain amino acid sequence (SEQ ID NO: 36)

[0320] Cetuximab heavy chain amino acid sequence (SEQ ID NO: 36)

[0321] Cetuximab heavy chain amino acid sequence (SEQ ID NO: 36)

[0322] Cetuximab heavy chain amino acid sequence (SEQ ID NO: 36)

[0323] Cetuximab heavy chain HCDR2 sequence (SEQ ID NO: 41)

[0324] Cetuximab heavy chain HCDR3 sequence (SEQ ID NO: 42)

[0325] Cetuximab light chain variable region VL (SEQ ID NO: 43)

[0326] Cetuximab heavy chain variable region VH (SEQ ID NO: 44)

[0327] In one embodiment, the antibody moiety for the ADC of the disclosure comprises all 6 CDR sequences of Cetuximab. In another embodiment, the antibody moiety for the ADC of the disclosure comprises the heavy chain variable region sequence and the light chain variable region sequence of Cetuximab. In yet another embodiment, the antibody moiety for the ADC of the disclosure comprises the heavy chain sequence and the light chain sequence of Cetuximab.

[0328] In some embodiments, the Ab unit of the ADC of the disclosure comprises three CDRs of the heavy chain variable region (VH) sequence of SEQ ID NO: 44 and three CDRs of the light chain variable region (VL) sequence of SEQ ID NO: 43, and preferably, wherein the CDRs are defined according to Kabat or IMGT or a combination thereof.

[0329] In some embodiments, the Ab unit of the ADC of the disclosure comprises 3 heavy chain complementarity determining regions (HCDRs) and 3 light chain complementarity determining regions (LCDRs), wherein:

[0330] According to the Kabat definition, HCDR1 comprises or consists of the amino acid sequence of SEQ ID NO: 40, HCDR2 comprises or consists of the amino acid sequence of SEQ ID NO: 41, HCDR3 comprises or consists of the amino acid sequence of SEQ ID NO: 42, LCDR1 comprises or consists of the amino acid sequence of SEQ ID NO: 37, LCDR2 comprises or consists of the amino acid sequence of SEQ ID NO: 38, and LCDR3 comprises or consists of the amino acid sequence of SEQ ID NO: 39.

[0331] In one embodiment, the Ab unit of the ADC of the present disclosure comprises a heavy chain variable region, wherein the heavy chain variable region comprises: the amino acid sequence set forth in SEQ ID NO: 44, or an amino acid sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity thereto.

[0332] In one embodiment, the Ab unit of the ADC of the present disclosure comprises a light chain variable region, wherein the light chain variable region comprises: the amino acid sequence set forth in SEQ ID NO: 43, or an amino acid sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity thereto.

[0333] In some preferred embodiments, the Ab unit of the ADC of the present disclosure comprises a heavy chain variable region and a light chain variable region, wherein the heavy chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 44, and wherein the light chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 43.

[0334] In some embodiments, the Ab unit of the ADC of the present disclosure preferably further comprises a heavy chain constant region and / or a light chain constant region of an antibody. Preferably, the heavy chain constant region is a heavy chain constant region derived from a human immunoglobulin. Preferably, the light chain constant region is a light chain constant region derived from a human immunoglobulin. In some aspects, the heavy chain constant region comprised in the Ab unit can be of any isotype or subtype, e.g., a heavy chain constant region of an IgGl, IgG2, IgG3, or IgG4 isotype, and preferably an IgGl, IgG2, or IgG4 heavy chain constant region, in particular a human IgGl heavy chain constant region. In further aspects, the light chain constant region comprised in the Ab unit can be a kappa light chain constant region or a lambda light chain constant region, in particular a human kappa light chain constant region.

[0335] In some embodiments, the Ab unit of the ADC of the present disclosure comprises a human IgGl heavy chain constant region. Preferably, the heavy chain constant region comprises the amino acid sequence of SEQ ID NO: 34, or an amino acid sequence comprising at least one, two or three, but not more than 20, 10 or 5 amino acid alterations relative to the amino acid sequence of SEQ ID NO: 34, or a sequence having at least 95-99% identity to the amino acid sequence of SEQ ID NO: 34.

[0336] In some embodiments, the Ab unit of the ADC of the present disclosure comprises a human kappa light chain constant region. Preferably, the light chain constant region comprises the amino acid sequence of SEQ ID NO: 12, or an amino acid sequence that comprises at least one, two or three, but not more than 20, 10 or 5 amino acid alterations relative to the amino acid sequence of SEQ ID NO: 12, or a sequence with at least 95-99% identity to the amino acid sequence of SEQ ID NO: 12.

[0337] In some embodiments, the Ab unit of the ADC of the present disclosure is a full-length antibody comprising a heavy chain constant region and a light chain constant region. In some embodiments, the Ab unit is a tetrameric structure formed by two light chains and two heavy chains. In still other embodiments, the Ab unit is an IgG antibody, in particular an IgGl antibody.

[0338] In some preferred embodiments, the Ab unit of the ADC of the present disclosure comprises a heavy chain and a light chain, wherein: the heavy chain comprises or consists of the amino acid sequence set forth in SEQ ID NO: 36, or an amino acid sequence with at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% sequence identity thereto. In other preferred embodiments, the Ab unit of the ADC of the present disclosure comprises a heavy chain and a light chain, wherein: the light chain comprises or consists of the amino acid sequence set forth in SEQ ID NO: 35, or an amino acid sequence with at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% sequence identity thereto.

[0339] In some more preferred embodiments, the Ab unit of the ADC of the present disclosure comprises:

[0340] (g) a heavy chain comprising the amino acid sequence of SEQ ID NO: 36, and

[0341] (h) a light chain comprising the amino acid sequence of SEQ ID NO: 35.

[0342] Cancers that can be treated with the ADCs of the present disclosure targeting EGFR include, but are not limited to, various primary and metastatic solid tumors, such as lung cancer (e.g., lung adenocarcinoma, lung squamous cell carcinoma, and non-small cell lung cancer), head and neck cancer (e.g., head and neck squamous cell carcinoma), nasopharyngeal cancer, esophageal cancer, biliary tract cancer, colon cancer, colorectal cancer, pancreatic cancer, gastric cancer, and glioblastoma.

[0343] First payload - D1

[0344] D1 useful in the ADCs of the present disclosure is a bifunctional cyclic dinucleotide (CDN) having the following formula:

[0345] wherein

[0346] B1is adenine optionally substituted with X wherein X is selected from H, Cl, F or -NHC 1-6 alkyl; or optionally substituted guanine b alkyl; or optionally substituted guanine wherein R b is selected from H or -C 1-6 alkyl;

[0347] R1and R1’ are each independently selected from H, F or -OH;

[0348] B2is guanine wherein R b is selected from H or -C 1-6 alkyl;

[0349] denotes that the phosphodiester bond can be attached to the 2’ or 3’ position of the pentose, the position not forming a ring with the phosphate being substituted with R2and R2’; and

[0350] R2and R2’ are each independently selected from H, -OH or F;

[0351] or a pharmaceutically acceptable salt, ester, isomer, solvate, prodrug or isotopically-labeled form thereof.

[0352] In a preferred embodiment, the CDN of formula (II) (D1) is covalently bound to the linker unit (L) in the ADC of formula (X) via any one of its -SH.

[0353] In a particular embodiment, the two phosphorothioate bonds in D1 of the ADC of the present disclosure are present in the R,R, S,S, S,R or R,S configuration or mixtures thereof. In a preferred embodiment, the two phosphorothioate bonds in the compounds of the present disclosure are present in the R,R, S,S, S,R or R,S configuration in substantially pure form, particularly preferably in the R,R configuration in substantially pure form.

[0354] In an embodiment of the compound of formula (II), B1is adenine optionally substituted with X wherein X is selected from H.

[0355] In an embodiment of the compound of formula (II), B1is adenine optionally substituted with X wherein X is selected from Cl or F.

[0356] In an embodiment of the compound of formula (II), B1is adenine substituted with X wherein X is -NHC 1-6alkyl, for example -NHCH3, -NHCH2CH3, -NHCH2CH2CH3, preferably -NHCH3.

[0357] In an embodiment of the compound of formula (II), B1is adenine b substituted guanine wherein R b is selected from H or -C 1-6 alkyl, for example R b is -CH3, -CH2CH3, -CH2CH2CH3, preferably -CH3.

[0358] In an embodiment of the compound of formula (II), R1and R1are both H, or one is H and the other is F, or one is H and the other is OH, or both are F.

[0359] In an embodiment of the compound of formula (II), B2is guanine

[0360] In an embodiment of the compound of formula (II), R2and R2are both H, or one is H and the other is F, or one is H and the other is OH, or both are F; preferably one is H and the other is OH.

[0361] In an embodiment of the compound of formula (II), B1is adenine wherein X is selected from H, CI, F or -NHC 1- 6alkyl; or guanine wherein R b is -C 1-6 alkyl; B2is guanine R1and R1are both H, or one is H and the other is F, or one is H and the other is OH; R2and R2one is H and the other is OH.

[0362] The compound of formula (II) of the present disclosure, also encompasses any combination between the various embodiments described above and their preferred or exemplified ways.

[0363] In a further particular embodiment, the drug D1in the ADC of the present disclosure is a bifunctional cyclic dinucleotide (CDN) having the following formula:

[0364] wherein B1, B2, R1, R1, R2, R2have the meanings defined above for the compound of formula (II) and each of its particular embodiments.

[0365] In an embodiment of the compound of formula (II-a) or formula (II-b), B1is adenine optionally substituted with X wherein X is selected from H, Cl, F or -NHC 1-6 alkyl, or optionally substituted guanine b alkyl, or optionally substituted guanine wherein R b -C 1-6 alkyl; B2 is guanine In a particular such embodiment, R1and R1are both H, or one is H and the other is F, or one is H and the other is OH; in a particular such embodiment, the F or OH and B1are on the same side of the ribose.

[0366] In one embodiment of a compound of formula (II-a) or (II-b), B2is guanine In a particular such embodiment, R2and R2are both H, or one is H and the other is selected from -OH or F, preferably one is H and the other is -OH; in a particular such embodiment, the F or OH and B2are on the opposite side of the ribose.

[0367] In one embodiment of a compound of formula (II-a) or (II-b), B1is adenine optionally substituted with X wherein X is selected from H, Cl, F or -NHC 1-6 alkyl, or optionally substituted guanine b alkyl, or optionally substituted guanine wherein R b -C 1-6 alkyl; B2 is guanine R1and R1are both H, or one is H and the other is F, or one is H and the other is OH; R2and R2are both H, or one is H and the other is OH, preferably one is H and the other is -OH.

[0368] In one embodiment of a compound of formula (II-a), B1is and B2is In one particular such embodiment, R1and R1are both H; in another particular such embodiment, R1and R1are one H and the other F. Further, in each of the particular such embodiments, R2and R2are both H, or one is H and the other is OH, preferably one is H and the other is -OH.

[0369] In one embodiment of a compound of formula (II-a), B1is and B2is In one embodiment of the compound of formula (II-b), B1is

[0370] In one embodiment of the compound of formula (II-b), B1is and B2is In one embodiment of the compound of formula (II-b), B1is

[0371] In one embodiment of the compound of formula (II-b), B1is and B2is In one embodiment of the compound of formula (II-b), B1is

[0372] In one embodiment of the compound of formula (II-b), B1is preferably and B2is In one embodiment of the compound of formula (II-b), B1is

[0373] In one embodiment of the compound of formula (II-b), B1is wherein R b is -C 1-6 alkyl, for example -CH3, -CH2CH3, -CH2CH2CH3, preferably -CH3; and B2is In a particular embodiment of the compound of formula (II), R1and R1are both H; in another particular embodiment of the compound of formula (II), one of R1and R1is H and the other is F; in another particular embodiment of the compound of formula (II), one of R1and R1is H and the other is OH. Further, in each of said embodiments, R2and R2are both H, or one is H and the other is OH, preferably one is H and the other is -OH.

[0374] In an embodiment of the compound of formula (II-b), B1is and B2is In a particular embodiment of the compound of formula (II), R1and R1are both H; in another particular embodiment of the compound of formula (II), one of R1and R1is H and the other is F; in another particular embodiment of the compound of formula (II), one of R1and R1is H and the other is OH. Further, in each of said embodiments, R2and R2are both H, or one is H and the other is OH, preferably one is H and the other is -OH.

[0375] In the above compound of formula (II-a) or formula (II-b) and each of its particular embodiments, the two phosphorothioate bonds are present in the R,R, S,S, S,R or R,S configuration or mixtures thereof; preferably in the R,R, S,S, S,R or R,S configuration in substantially pure form, particularly preferably in the R,R configuration in substantially pure form.

[0376] The compound of formula (II-a) / (II-b) of the present disclosure also encompasses any combination between the above embodiments and preferred or exemplary ways thereof.

[0377] In a further particular embodiment, D1in the ADC of the present disclosure is a CDN having the following subformula

[0378] wherein B1, B2, R1, R1, R2, R2have the meaning as defined above for the compound of formula (II) or each of its particular embodiments; more particularly, the meaning as defined above for the compound of formula (II-a) / (II-b) or each of its particular embodiments.

[0379] In an embodiment of the compound of formula (II-a') or formula (II-b'), B1is adenine optionally substituted with X wherein X is selected from H, CI, F or -NHC 1-6 alkyl, or guanine optionally substituted with R b wherein R b is selected from -C 1-6 alkyl; for example ​ In a particular embodiment of the compound of formula (II-a') or (II-b'), R1and R1' are both H, or wherein R1' is H and R1is F, or wherein R1' is H and R1is OH.

[0380] In an embodiment of the compound of formula (II-a') or (II-b'), B1is and R1and R1' are both H, whereby this B1together with the ribose to which it is attached forms the nucleoside anticancer drug cladribine; or when R1is F and R1' is H, i.e. F and B1are located on the same side of the ribose, whereby this B1together with the ribose to which it is attached forms the nucleoside anticancer drug clofarabine.

[0381] In an embodiment of the compound of formula (II-a') or (II-b'), B1is and R1is OH and R1' is H, whereby this B1together with the ribose to which it is attached forms the nucleoside anticancer drug nelarabine.

[0382] In an embodiment of the compound of formula (II-a') or (II-b'), B1is and R1is OH and R1' is H, whereby this B1together with the ribose to which it is attached forms the nucleoside anticancer drug nelarabine.

[0383] In an embodiment of the compound of formula (II-a') or (II-b'), B2is guanine R2and R2' are both H, or R2' is H and R2is selected from -OH or F, preferably R2' is H and R2is -OH.

[0384] In an embodiment of the compound of formula (II-a') or (II-b'), B1is adenine optionally substituted with X wherein X is selected from H, CI, F or -NHC 1-6 alkyl; or guanine optionally substituted with R b alkyl; or guanine optionally substituted with R wherein R b is selected from -C 1-6 alkyl; B2is guanine R1and R1' are both H, or wherein R1' is H and R1is F, or wherein R1' is H and R1is OH; R2and R2' are both H, or wherein R2' is H and R2is OH, preferably R2' is H and R2is OH.

[0385] In an embodiment of the compound of formula (II-a'), B1is and B2is In one specific embodiment, both R1 and R1' are H; in another specific embodiment, R1 is F and R1' is H. Further, in each of these specific embodiments, both R2 and R2' are H, or R2' is H and R2 is OH, preferably R2' is H and R2 is OH.

[0386] In one embodiment of a compound of formula (II-a'), B1 is And B2 is In one specific embodiment, both R1 and R1' are H; in another specific embodiment, R1 is F and R1' is H. Further, in each of these specific embodiments, both R2 and R2' are H, or R2' is H and R2 is OH, preferably R2' is H and R2 is OH.

[0387] In one embodiment of a compound of formula (II-b'), B1 is... And B2 is In one specific embodiment, both R1 and R1' are H; in another specific embodiment, R1 is F and R1' is H; in yet another specific embodiment, R1 is OH and R1' is H. Further, in each of these embodiments, both R2 and R2' are H, or R2 is OH and R2' is H, preferably R2 is OH and R2' is H.

[0388] In one embodiment of a compound of formula (II-b'), B1 is... And B2 is In one specific embodiment, both R1 and R1' are H; in another specific embodiment, R1 is F and R1' is H; in yet another specific embodiment, R1 is OH and R1' is H. Further, in each of these embodiments, both R2 and R2' are H, or R2 is OH and R2' is H, preferably R2 is OH and R2' is H.

[0389] In one embodiment of a compound of formula (II-b'), B1 is... Preferred And B2 is In one specific embodiment, both R1 and R1' are H; in another specific embodiment, both R1 and R1' are H; in yet another specific embodiment, R1 is F and R1' is H; in yet another specific embodiment, R1 is OH and R1' is H. Further, in each of these embodiments, both R2 and R2' are H, or R2 is OH and R2' is H, preferably R2 is OH and R2' is H.

[0390] In an embodiment of the compound of formula (II-b'), B1is wherein R b is -C 1-6 alkyl, for example -CH3, -CH2CH3, -CH2CH2CH3, preferably -CH3; and B2is In a particular such embodiment, R1and R1' are both H; in another particular such embodiment, R1is F and R1' is H; in another particular such embodiment, R1is OH and R1' is H. Further, in each of said particular embodiments, R2and R2' are both H, or R2is OH and R2' is H, preferably R2is OH and R2' is H.

[0391] In an embodiment of the compound of formula (II-b'), B1is and B2is In a particular such embodiment, R1and R1' are both H; in another particular such embodiment, R1is F and R1' is H; in another particular such embodiment, R1is OH and R1' is H. Further, in each of said particular embodiments, R2and R2' are both H, or R2is OH and R2' is H, preferably R2is OH and R2' is H.

[0392] It is noted that the D1 moiety in the ADCs of the present disclosure encompasses each of the above particular embodiments, further encompasses embodiments comprising any combination or sub-combination of the above particular embodiments, and further encompasses embodiments comprising any combination of any of the above preferences or exemplifications.

[0393] It is noted that when the CDN (D1) of formula (II), (II-a), (II-b), (II-a'), (II-b') is covalently bonded to the linker unit (L) in the ADC of formula (X), it is bonded through any one of the following sites of the CDN:

[0394] (1) any one -SH; or

[0395] (2) an amino group on the B1or B2base; or

[0396] (3) an OH on the sugar ring.

[0397] In a preferred embodiment, the CDN (D1) of the above formula is covalently bonded to the linker unit (L) in the ADC of formula (X) through the free thiol of any one of its phosphates.

[0398] In some embodiments, the CDN (D1) of each of the above formulae is covalently bound to the linker unit (L) in the ADC of formula (X) via the thiol of the phosphorothioate formed by the 3 OH on the B1 -linked nucleotide ring and the 5' hydroxyl of the B2-linked nucleotide.

[0399] The D1 moiety in the ADC of the present disclosure preferably comprises the following compound, pharmaceutically acceptable salts, esters, isomers, solvates, prodrugs, or isotopically-labeled versions thereof,

[0400] It is noted that the present disclosure encompasses ADC compounds formed from any of the above general, specific or preferred CDN compounds with the linker unit, the payload D2 and the antibody as defined herein. It is also noted that the general or specific example CDN compounds of the present disclosure can be prepared and characterized structurally and for activity according to the methods disclosed in WO2022083584A1.

[0401] Second Payload - D2

[0402] The dual payload antibody conjugate drug of the present disclosure, in addition to the first payload as defined above, covalently binds a second payload via the linker unit, which can be any therapeutic agent compatible with the cGAS-STING pathway, preferably a small molecule compound, more preferably an anti-tumor agent.

[0403] In some embodiments, the second payload of the dual payload antibody conjugate drug of the present disclosure is the same as the first payload, e.g., the second payload can also be selected from the bifunctional CDN STING agonists as defined herein, but can be the same or different specific molecule.

[0404] In other embodiments, the second payload of the dual payload antibody conjugate drug of the present disclosure is different from the first payload, e.g., the second payload is selected from other therapeutic agents with different mechanisms of action.

[0405] In some embodiments of the present disclosure, D2 in the ADC of the present disclosure is selected from the following camptothecin class compounds that can be synthesized and characterized based on CN115990269:

[0406] The following commercially available camptothecin class drugs are preferred:

[0407] In some embodiments, the second payload in the ADC of the present disclosure is selected from PARP inhibitors, e.g., the following commercially available PARP inhibitors:

[0408] In some embodiments, the second payload in the ADC of the present disclosure is selected from nucleoside derivatives, such as the following commercially available nucleoside derivatives:

[0409] In some embodiments, the second payload in the ADC of the present disclosure is selected from folate antagonists, such as the following commercially available folate antagonists:

[0410] In some embodiments, the second payload in the ADC of the present disclosure is selected from microtubule inhibitors, such as the following commercially available microtubule inhibitors:

[0411] In some embodiments, the second payload in the ADC of the present disclosure is selected from nuclear receptor modulators, such as the following commercially available nuclear receptor modulators:

[0412] In some embodiments, the second payload in the ADC of the present disclosure is selected from immunomodulators, such as the following commercially available immunomodulators:

[0413] In some embodiments, the second payload in the ADC of the present disclosure is selected from epigenetic modulators, such as the following commercially available epigenetic modulators:

[0414] In some embodiments, the second payload in the ADC of the present disclosure is selected from topoisomerase II inhibitors, such as the following commercially available topoisomerase II inhibitors:

[0415] In some embodiments, the second payload in the ADC of the present disclosure is selected from phosphatase inhibitors, such as the following commercially available phosphatase inhibitors:

[0416] In some embodiments, the second payload in the ADC of the present disclosure is selected from kinase inhibitors, such as the following commercially available kinase inhibitors:

[0417] In some embodiments, the second payload in the ADC of the present disclosure is other antineoplastic agents, such as the following commercially available antineoplastic agents:

[0418] In some embodiments, the second payload in the ADCs of the present disclosure can be selected from a topoisomerase I inhibitor such as camptothecin or a derivative thereof, a PARP inhibitor, a kinase inhibitor, a topoisomerase II inhibitor, a nucleoside derivative, a microtubule inhibitor, a nuclear receptor modulator, in particular as indicated above.

[0419] In particular embodiments, the second payload in the ADCs of the present disclosure can be selected from

[0420] It is noted that the payloads listed herein encompass the respective pharmaceutically acceptable salts, esters, isomers, solvates, prodrugs or isotopically labeled forms, and are each attached to the linker unit via, for example, a hydroxyl, amino or heterocyclic nitrogen atom in their structure.

[0421] Linker Unit L

[0422] In the ADCs described herein, D1 and D2 are linked to the antibody or antigen binding fragment by a linker unit. The linker unit couples D1 and D2 to the antibody by forming a covalent bond to D1 at at least one position, forming a covalent linkage to D2 at at least another position, and forming a covalent linkage to the antibody or antigen binding fragment at yet another position. The linker unit can be monovalent with respect to D1 or D2, such that a single D1 or D2 is covalently coupled to the antibody or antigen binding fragment, or it can be multivalent with respect to D1 or D2, such that more than one D1 or D2 is covalently coupled to the antibody or antigen binding fragment. As used herein, the expression "linker unit" is intended to encompass unconjugated, partially conjugated (i.e., conjugated only to the CDN or only to D2 or only to Ab) and fully conjugated forms (i.e., conjugated to the CDN and D2 and Ab) of the linker unit.

[0423] The linker unit L suitable for use in the ADCs of the present disclosure can be any linker capable of effecting coupling of the drug of the present disclosure to an antibody. Suitably, the addition of the linker should ensure sufficient stability of the ADC of the present disclosure in the circulation system, should not cleave prematurely in circulation to trigger off-target toxicity, while providing rapid and efficient release of the payload in the target site (e.g., tumor cell or tumor environment). For example, the linker unit can be stable to the extracellular environment and serum chemistry, or can comprise an intentionally unstable linker unit and can release the payload in the extracellular environment or tumor microenvironment.

[0424] In some embodiments, the linker unit comprises a bond designed to release the payload upon internalization of the ADC within a cell. In some particular embodiments, the linker unit comprises a bond designed to be cleaved and / or catabolized or otherwise specifically or non-specifically degraded within a cell.

[0425] In some embodiments, the linker unit in the ADC of the present disclosure is a non-degradable linker. Examples of non-degradable linker units include, but are not limited to, thioether linkers, N-succinimidyl-4-(N-maleimidomethyl)cyclohexane-l-carboxylate (SMCC), and maleimidocaproyl (MC). Generally, such linkers are more stable, and the ADCs comprising such linkers must be internalized by the cell, degraded by lysosomal proteases in the cell to release the drug active molecule.

[0426] In still other embodiments, the linker unit in the ADC of the present disclosure is a degradable linker unit, which comprises one or more chemically or enzymatically degradable chemical bonds. The drug release of the ADC comprising such linker is triggered by the nature of the cleavage site in the linker. Thus, the cleavage site of such linker can be designed according to the characteristics of the target therapeutic site, such as the tumor cell lysosome and / or the tumor environment.

[0427] In some embodiments, the degradable linker unit is an enzymatically degradable linker unit, and is more stable than chemically unstable linkers in the plasma and extracellular environment. Such linker can be based on or include a peptide region, or be a non-peptide linker, such as a peptide mimetic, or a saccharide, an ester, and an amide. Such linker can be cleaved by a tumor-specific enzyme, such as a tumor-specific protease having increased abundance in the tumor and / or the tumor environment, including but not limited to lysosomal proteases, such as cathepsins (e.g., cathepsin B), endoaspartic acid, fibrinolysin, esterase, or amidase, etc.

[0428] Generally, the enzymatically degradable linker unit can be composed of a self-immolative linker, a cleavable linker, optionally a property-modulating unit, and an antibody linker. The self-immolative linker connects the payload to the cleavable linker, facilitating the release of the payload from the rest of the conjugate, such as p-aminobenzyl, p-hydroxybenzyl, p-aminobenzyloxyacyl, p-hydroxybenzyloxyacyl, 2-aminomethyl-l-carbonylpiperidine, 2-aminomethyl-l-carbonylpiperazine, etc.; the cleavable linker under an enzyme-based release mechanism comprises a peptide or a peptide analog, an ester (such as a carbamate, a sulfate), an amide, a disulfide-containing moiety, a saccharide, etc., which can be recognized by an enzyme; the addition of a property-modulating unit can be beneficial to improve the properties of the ADC, such as the stability in the blood circulation, the drug efficacy of the ADC at the target site, and the optimization of the hydrophilicity of the ADC, such as when the drug is highly hydrophobic, it can be considered (but not necessarily) to add a PEG unit or a saccharide unit such as a monosaccharide or disaccharide unit or a derivative thereof to optimize the hydrophilicity of the ADC, such as to reduce precipitation and aggregation; the antibody linker is to connect the antibody or antigen-binding fragment targeting the antigen to the rest of the conjugate, which has a functional group that can form a bond with the functional group on the antibody.

[0429] In some embodiments, the linker unit L in the ADC of the present disclosure has the structure of the following general formula:

[0430] wherein G, E, W, P1, P2, A1, A2, S1, S2 have the meanings as defined above for formula (I), respectively, wherein the wavy line indicates the point of attachment to the antibody and the asterisk indicates the point of attachment to the payload.

[0431] In some embodiments, the linker unit L in the ADC of the present disclosure has the structure of the following sub-formulae, depending on the presence or absence of E, S1 and / or S2:

[0432] The following gives general, specific or preferred embodiments for each possible component of the linker unit L, respectively. It is noted that the present disclosure encompasses linker units L obtained by any combination of the general, specific or preferred embodiments of each component with the general, specific or preferred embodiments of any one or more of the remaining components; correspondingly, the present disclosure encompasses ADC compounds obtained by any combination of the linker units obtained by said any combination with the general, specific or preferred embodiments of the antibody and the drug moiety as defined in the present disclosure.

[0433] G - antibody linker

[0434] The function of the antibody linker is to connect the antibody or antigen binding fragment targeting the antigen to the rest of the ADC, which has a functional group that can form a bond with a functional group on the antibody.

[0435] In some embodiments, the antibody linker in the ADC of the present disclosure is connected to a S atom in the antibody; in other embodiments, the antibody linker in the ADC of the present disclosure is connected to a N atom in the antibody; in other embodiments, the antibody linker in the ADC of the present disclosure is connected to a C atom in the antibody. In the ADC of the present disclosure, it is preferred that the antibody linker is connected to a sulfur atom of the antibody.

[0436] In specific embodiments, G in the ADC of the present disclosure has the following structure: -G1-G2-,

[0437] wherein:

[0438] G1 is selected from:

[0439] • 5-10 membered heterocyclyl, containing 1 or 2 heteroatoms selected from N, S and O, wherein the ring carbon atoms are optionally oxidized;

[0440] • wherein the left-hand * indicates the point of attachment to the antibody and the right-hand indicates the point of attachment to G2;

[0441] G2is selected from -C 1-10 alkylene-C(=O)-, -C 1-10 alkylene-C(=O)-NH-C 1-10 alkylene-O-C 1-10 alkylene-C(=O)-, wherein G2is attached to G1via its -C(=O)- to the property modulating unit E (when present) or branching unit W (when E is absent), the other end group being attached to G1, or

[0442] G2is selected from -C 1-10 alkylene-NH-, wherein G2is attached to G1via its -NH- to the property modulating unit E (when present) or branching unit W (when E is absent);

[0443] wherein -C 1-10 alkylene- is optionally substituted with a Bu group.

[0444] In some embodiments, -C 1-10 alkylene- is optionally substituted with a Bu group selected from H, deuterium, halogen, NO2, CN, -OR h , -OR h , -N(R h )2, -COR h , -CO2R h , -C-(O)C(O)R h , -C(O)CH2C(O)R h , -S(O)R h , -SO2R h , C(O)N(R h )2, -SO2N(R h )2, -OC(O)R h , -N(R h )SO2R h and -C 1-6 alkyl optionally substituted with a proline group, wherein R h is H or -C 1-6 alkyl optionally substituted with halogen, or wherein two R h groups attached to the same N atom and the nitrogen to which they are attached form a 4-7 membered heterocyclyl; preferably, the substituent of G2is an aminoalkyl moiety such as -(CH2) 1-6 NH2, -(CH2) 1-6 NHR h or -(CH2) 1- 6N(R h )2, or wherein two R hthe group and the nitrogen to which they are attached together form an azetidinyl, pyrrolidinyl or piperidinyl group.

[0445] In other embodiments, -C 1-10 alkylene- is optionally substituted by a Bu group of formula (G):

[0446] wherein,

[0447] T0is -C 1-6 alkylene-;

[0448] T is selected from -C(R a )2-, -0-, -NR a - or is absent;

[0449] M is selected from -CO-, -0-, -NR a - or is absent;

[0450] Z is selected from a glycosyl group or a derivative thereof, and a hydrophilic peptide comprising , preferably a glycosyl group or a derivative thereof and a hydrophilic peptide comprising ;

[0451] R a is selected from H or C 1-6 alkyl;

[0452] subunit is selected from a natural amino acid residue and a non-natural amino acid residue;

[0453] n is an integer from 0 to 4, for example 0-2, 1-2, 1-4, 2-4;

[0454] m is an integer from 0 to 20, for example 0-8, 0-6, 0-4, 0-2, 1-20, 1-10, 2-10, 2-8, 2-6, 2-4, 4-14, 4-12, 4-10, 5-10, 6-10, 6-12, 8-10, 8-14.

[0455] In some Bu embodiments, m is 1-20, 1-10, 2-10, 2-8, 2-6, 2-4, 4-14, 5-10, 6-10, 6-12, 8-10, 8-14, for example 4-14, 6-12 or 5-10.

[0456] In some Bu embodiments, T0is -C 1-3 alkylene-, preferably methylene.

[0457] In some Bu embodiments, T is -C(R a )2-, for example methylene.

[0458] In some Bu embodiments, T is -O-.

[0459] In some Bu embodiments, T is -NR a -, for example -NH-.

[0460] In some Bu embodiments, T is absent.

[0461] In some Bu embodiments, M is -CO-.

[0462] In some Bu embodiments, M is -O-.

[0463] In some Bu embodiments, M is -NR a -, for example -NH-.

[0464] In some Bu embodiments, M is absent.

[0465] In some Bu embodiments, T0is -C 1-6 alkylene-; T is -O- or -NR a -; M is absent; n is 0.

[0466] In some Bu embodiments, T0is -C 1-6 alkylene-; T is absent; M is -O- or -NR a -; n is 0.

[0467] In some Bu embodiments, T0is -C 1-6 alkylene-; T is -O- or -NR a -; M is -CO-; n is 0.

[0468] In some Bu embodiments, T0is -C 1-6 alkylene-; T is absent; M is -CO-; n is 0.

[0469] In some Bu embodiments, R a is H, in other Bu embodiments, R a is C 1-6 alkyl, for example C 1-3 alkyl, preferably methyl.

[0470] In any of the above Bu embodiments, Z can be a glycosyl group or derivative thereof, as generally, specifically or preferably defined for a carbonyl group or derivative thereof in the section "S1 or S2 - solubilising unit" below; preferably selected from the monosaccharide, disaccharide or derivative thereof as defined therein, more preferably a five- or six-carbon sugar, or a uronic acid, amino sugar, acylated amino sugar, amino uronic acid or acylated amino uronic acid derivative thereof, still more preferably glucose, mannose, galactose or a respective derivative thereof.

[0471] In any of the above embodiments of Bu, Z can be a hydrophilic peptide comprising repeating subunits of amino acid residues, wherein the amino acid residues as repeating subunits can be the conventional 20 natural amino acids, and accordingly, the combinations of values of R, R', R" in the repeating subunit -CO-CR'R"-NR- correspond to the respective values of alanine (Ala), arginine (Arg), aspartic acid (Asp), asparagine (Asn), histidine (His), glycine (Gly), glutamic acid (Glu), glutamine (Gln), phenylalanine (Phe), lysine (Lys), leucine (Leu), serine (Ser), tyrosine (Tyr), threonine (Thr), isoleucine (Ile), proline (Pro), tryptophan (Trp), valine (Val), cysteine (Cys), methionine (Met), preferably to the respective values selected from arginine, serine, threonine, tyrosine, cysteine, aspartic acid, asparagine, glutamic acid, glutamine, lysine, histidine, glycine, tryptophan. The amino acid residues as subunits can also be amino acids other than the conventional 20 natural amino acids, such as ornithine (Orn), β-alanine (β-Ala), citrulline (Cit), sarcosine (Sar), and R, R', R" in the repeating subunit -CO-CR'R"-NR- are different from those of the respective groups or fragments of the 20 amino acids.

[0472] In some embodiments, the hydrophilic peptide can be a repetition of a single amino acid unit, such as poly-sarcosine, poly-arginine, and poly-glycine; in other embodiments, the hydrophilic peptide can also be a mixed repetition of different subunits, such as the hydrophilic peptide is a mixed hydrophilic peptide comprising the natural amino acids and the non-conventional amino acids.

[0473] In preferred embodiments, the amino acid units of the hydrophilic peptide are selected from sarcosine, arginine, and glycine.

[0474] In some specific embodiments of the hydrophilic peptide, the hydrophilic peptide is, for example but not limited to, by carboxyl-terminal connection or by amino-terminal connection preferably by carboxyl-terminal connection wherein R is as defined above, including but not limited to the residues carried by the amino group of the various amino acids listed herein for the hydrophilic peptide, for example R can be R a ; R a is selected from H or -C 1-6alkyl, preferably H or -CH3; preferably a poly(sarcosine), poly(arginine), poly(glycine) comprising 4-14 units or 4-10, 5-10 units, more preferably a poly(sarcosine) comprising 4-12, 6-12 units or 4-10, 5-10 units.

[0475] In some specific embodiments of the hydrophilic peptide comprising the hydrophilic peptide is wherein R is as defined above, including but not limited to the residues carried by the amino groups of the various amino acids listed herein for the hydrophilic peptide, e.g. R can be R a ; R a is selected from H or -C 1-6 alkyl, preferably H or -CH3, more preferably -CH3; preferably the fragment indicated by square brackets is a poly(sarcosine), poly(arginine), poly(glycine) comprising 4-14 units or 4-10, 5-10 units, more preferably a poly(sarcosine) comprising 4-12, 6-12 units or 4-10, 5-10 units.

[0476] In some specific embodiments of the hydrophilic peptide comprising the hydrophilic peptide is wherein R is as defined above, including but not limited to the residues carried by the amino groups of the various amino acids listed herein for the hydrophilic peptide, e.g. R can be R a ; R a is selected from H or -C 1-6 alkyl, preferably H or -CH3, more preferably -CH3; preferably the fragment indicated by square brackets is a poly(sarcosine), poly(arginine), poly(glycine) comprising 4-14 units or 4-10, 5-10 units, more preferably a poly(sarcosine) comprising 4-12, 6-12 units or 4-10, 5-10 units.

[0477] In some specific embodiments of the hydrophilic peptide comprising the hydrophilic peptide is wherein R is as defined above, including but not limited to the residues carried by the amino groups of the various amino acids listed herein for the hydrophilic peptide, e.g. R can be R a ; R a is selected from H or -C 1-6 alkyl, preferably H or -CH3, more preferably -CH3; preferably the fragment indicated by square brackets is a poly(sarcosine), poly(arginine), poly(glycine) comprising 4-14 units or 4-10, 5-10 units, more preferably a poly(sarcosine) comprising 4-12, 6-12 units or 4-10, 5-10 units.

[0478] In some embodiments of Bu, Z is selected from a glycosyl group or derivative thereof and comprises hydrophilic peptides; preferably selected from glucose, mannose, galactose, lactose, maltose, sucrose or their respective uronic acids, amino sugars, acylated amino sugars, amino sugar uronic acids or acylated amino sugar uronic acid derivatives, and hydrophilic peptides as generally or specifically defined herein, in particular poly-muscine, poly-arginine, poly-glycine, preferably poly-muscine comprising 4 to 14 units or 4 to 10, 5 to 10 units, hydrophilic peptides.

[0479] In some specific Bu embodiments, formula (G) is preferably wherein T0is -C 1- 3alkylene-, preferably methylene.

[0480] In some specific Bu embodiments, formula (G) is preferably wherein T0is -C 1- 3alkylene-, preferably methylene, Z is wherein R, m are each as generally or specifically defined above; in particular, the fragment indicated by square brackets is poly-muscine, poly-arginine, poly-glycine comprising 4 to 14 units or 4 to 10, 5 to 10 units, more preferably poly-muscine comprising 4 to 12, 6 to 12 units or 4 to 10, 5 to 10 units.

[0481] In some specific Bu embodiments, formula (G) is preferably wherein T0is -C 1- 3alkylene-, preferably methylene, Z is wherein R, R a , m are each as generally or specifically defined above; more in particular, the fragment indicated by square brackets is poly-muscine, poly-arginine, poly-glycine comprising 4 to 14 units or 4 to 10, 5 to 10 units, more preferably poly-muscine comprising 4 to 12, 6 to 12 units or 4 to 10, 5 to 10 units.

[0482] or, in some specific Bu embodiments, formula (G) is preferably, wherein T0is -C 1-3 alkylene-, preferably methylene, Z is wherein R, R a, m are each as generally or specifically defined above; more specifically, the moiety indicated by square brackets is a polyarginine, polyalanine, polyglycine comprising 4 to 14 units or 4 to 10, 5 to 10 units, more preferably a polyalanine comprising 4 to 12, 6 to 12 units or 4 to 10, 5 to 10 units.

[0483] In any of the above Bu embodiments, Z can also be

[0484] It is noted that the context of the present disclosure in defining the plurality of structural moieties refers to hydrophilic peptides, the definitions of which apply to the definition given herein for the moiety of formula (G).

[0485] In some embodiments, G1is a 5- to 10-membered heterocyclyl, preferably a 5- to 6-membered heterocyclyl containing 1 or 2 heteroatoms selected from N, O and S, such as a 5- to 6-membered heterocycloalkyl or a 5- to 6-membered heteroaryl, wherein the ring carbon atoms are optionally oxidized, such as, but not limited to wherein the left asterisk indicates the point of attachment to the antibody and the right wavy line indicates the point of attachment to G2.

[0486] In some embodiments, G1is selected from is the acid-amide moiety formed upon partial hydrolysis of the succinimidyl moiety.

[0487] In a preferred embodiment, G1is

[0488] In some embodiments, G2is -C 1-10 alkylene-C(=O)-, preferably -C 1-5 alkylene-C(=O)-, more preferably -(CH2)5-C(=O)-.

[0489] In some embodiments, G2is -C 1-10 alkylene-C(=O)-, preferably -C 1-5 alkylene-C(=O)-, more preferably -(CH2)5-C(=O)-, wherein the alkylene is substituted with a Bu group of formula (G) as defined above, preferably formula (G) is wherein T0is -C 1-3 alkylene-, preferably methylene, and Z is wherein R, R a , m are each as generally or specifically defined above; more specifically, R, R a are each independently C 1-6alkylene-, preferably methylene, Z is

[0490] In particular embodiments, -G1-G2- can be the following groups:

[0491] and the corresponding fragments wherein the methylene groups are replaced by Bu groups of formula (G) as defined above in general or preferably, wherein the left-hand * indicates the point of attachment to the rest of the antibody, and the right-hand indicates the point of attachment to the property modulating unit E (if present) or branching unit W (if E is not present).

[0492] In some particular embodiments, -G1-G2- has the following structure: Preferably More preferably wherein T0is -C 1-3 alkylene-, preferably methylene, Z is Preferably wherein R, R a , m are each as defined above in general or in particular; more particularly, R, R a are each independently C 1-6 alkyl, preferably -CH3, the fragment indicated in square brackets is a polyarginine, polyglycine, polyasparagine comprising 4-14 units or 4-10, 5-10 units, more preferably a polyasparagine comprising 4-12, 6-12 units or 4-10, 5-10 units.

[0493] In exemplary embodiments, G (-G1-G2-) in the ADC of the present disclosure has the following structure:

[0494] In some preferred embodiments, G in the ADC of the present disclosure has the following structure:

[0495] E - property modulating unit

[0496] The addition of a property modulating unit E can be beneficial to improve the properties of the ADC, such as stability in blood circulation, improve hydrophilicity, leading to a decrease in clearance rate and an increase in exposure.

[0497] The property-regulating unit E exists in series within the linker unit. It can be directly connected between G and W, or connected via another linking group, such as amino, carbonyl, alkyl carbonyl, amide, ester, urea, disulfide bridge, carbamate, hydrazone, imine, oxime, triazolyl, maleimide, alkenyl, alkynyl, or alkylene. For example, E can be linked via -NH-, -C(=O)-, or -C-. 1-4 Alkylene, -C 1-4 Alkylene -C(=O)-, -NH-C(=O)-(CH2OCH2)-C(=O)-, -C 1-4 Alkylene -NH-C(=O)-(CH2) 1-4 -O-(CH2) 1-4 -C(=O)-、-C 1-4 Alkylene-NH-(CH2) 1-4 -O-(CH2) 1-4 -C(=O)- connects between G and W.

[0498] In some implementations, E is absent.

[0499] In some embodiments, E is selected from polyamines, such as, but not limited to, polyethyleneimine, polylysine, spermine, dimer polyamines, arginine, amidine, protamine, cationic lipids, cationic porphyrins, quaternary ammonium salts of polyamines, and α-helical peptides.

[0500] In some implementations, E is selected from peptides, preferably hydrophilic peptides.

[0501] In some implementations, E stands for cyclodextrin unit.

[0502] In some implementations, E is polyamide.

[0503] In some implementations, E is a polysaccharide, a dendritic polymer, or a bifunctional hydrocarbon chain.

[0504] In some implementations, E is polyethylene glycol (PEG).

[0505] In some implementations, E is -NH-SO2-NH-.

[0506] In some embodiments, the ADC of the present disclosure can comprise at least two ethylene oxide (CH2CH2O) subunits constituting a PEG chain as a property modulating unit. The PEG chain may, for example, be in a linear, branched, or star configuration. Typically, the PEG chain is covalently linked in tandem between the antibody linker G and the branching unit W of the linker unit. The linkage of the PEG chain to the components within the linker unit is a cleavable bond, which can be a bond that is substantially insensitive to cleavage while circulating in the plasma but sensitive to cleavage in the intracellular or intratumoral environment. Exemplary linkages include, but are not limited to, amide bonds, ether bonds, ester bonds, hydrazone bonds, oxime bonds, disulfide bonds, peptide bonds, or triazole bonds, etc.

[0507] Methods of appending PEG units to the linker unit of the ADC are well known to those skilled in the art.

[0508] In some embodiments, the PEG unit has 2-12 ethylene oxide (CH2CH2O) subunits, for example at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, at least 10, at least 11, at least 12 ethylene oxide (CH2CH2O) subunits, for example 2 to 12, 2 to 10, 2 to 8, 2 to 6, 2 to 4, 4 to 12, 4 to 10, 4 to 8, 4 to 6, 6 to 12, 6 to 10, 6 to 8, 8 to 12, 8 to 10 ethylene oxide (CH2CH2O) subunits. In preferred embodiments, the PEG unit comprises at least 2, at least 4, at least 6, at least 8, at least 10, or at least 12 ethylene oxide (CH2CH2O) subunits.

[0509] Exemplary embodiments of the PEG fragment linked to the antibody linker G and the branching unit W include, but are not limited to, the following:

[0510] wherein the left-hand wavy line indicates the site of attachment to G2, the right-hand wavy line indicates the site of attachment to W, and each subscript c is independently selected from an integer from 2 to 12. In some embodiments, c is 2, 4, 8, or 12. In some embodiments, c is 2. In some embodiments, c is 4. In some embodiments, c is 8. In some embodiments, c is 12.

[0511] Branching unit W

[0512] The branching unit is any small molecule with three or more identical or different functional groups that allows conjugation of the antibody and at least two payloads, which can be selected from amino acids (including natural and unnatural amino acids) and derivatives thereof, saccharide units and derivatives thereof, aryl substituted compounds and derivatives thereof, substituted hydrocarbon groups and derivatives thereof, amino-containing derivatives, triazole-containing derivatives, disulfide substituted compounds.

[0513] In some embodiments, the branching unit W in the ADC of the present disclosure is an amino acid residue, for example

[0514] In some embodiments, the branching unit W in the ADC of the present disclosure is a structural fragment of the general formula:

[0515] wherein W is selected from O, S, NR c , CH 2- or is absent;

[0516] R a and R c are each independently selected from H, optionally substituted C1-C 20 alkyl, optionally substituted C2-C 20 alkenyl;

[0517] y 1 , y 2 are each independently 0, 1, 2, 3, 4, 5 or 6;

[0518] For example, the middle N-terminus is linked to the property adjustment unit E or the antibody linker G (absent), and the two carboxyl terminals are linked to the cleavable linker P1 or P2, respectively.

[0519] In other embodiments, the branching unit W in the ADC of the present disclosure can comprise or be selected from the following structures:

[0520] In some embodiments, the branching unit is linked to the property adjustment unit E (when present) or the antibody linker G (when E is absent) through one of the N-termini.

[0521] Preferably, the branching unit W is an amino acid residue, more preferably comprising a structural fragment linked to the property adjustment unit E (when present) or the antibody linker G (when E is absent) through one of the N-termini.

[0522] P1 or P2 - cleavable linker

[0523] In one aspect, the cleavable linkers P1 or P2 in the linker unit of the ADCs of the present disclosure are enzymatically cleavable units, i.e. substrates that can be cleaved or broken by enzymes. In order to limit or minimize the non-targeted toxicity of the ADCs, while ensuring the release of the payload at the target tumor site, the cleavable linkers are designed to be substrates that are specifically cleaved by enzymes present in the vicinity of or inside the target cells, preferably at a higher level or activity in the vicinity of or inside the target cells than in other parts of the body, thereby ensuring that the ADCs are specifically recognized, cleaved and release the payload molecule in the target cells / tissues, where its biological function is exerted.

[0524] Thus, the ADCs of the present disclosure are stable in biological fluids until they reach their target, e.g. tumor cells / tissues. Due to the specific release of the ADCs, the toxicity resulting from the administration of the ADCs of the present disclosure will be less and the activity will be maximally exerted compared to the administration of the payload alone.

[0525] In some embodiments, P1 or P2 in the linker unit of the ADCs of the present disclosure is a dipeptide, tripeptide or oligopeptide consisting of an amino acid sequence that is specifically recognized and cleaved by a protease, preferably a non-mammalian protease or an endogenous mammalian protease present in the vicinity or inside of the target cell, such as, but not limited to: beta-site APP-cleaving enzyme 1 (BACE1), Cathepsin D (CTSD), Calpain-1 (CAPN1), Endoaspase (Lugemain), Caspase 1 (Casp1), Caspase 2 (Casp2), Caspase 3 (Casp3), Caspase 5 (CASPS), Caspase 6 (Casp6), Caspase 7 (Casp7), Caspase 8 (Casp8), Caspase 9 (Casp9), Cathepsin B (CTSB), Cathepsin K (CTSK), Cathepsin L (CTSL), Cathepsin S (CTSS), Esterases (such as cholinesterase, alkaline phosphatase, phosphodiesterase, sulfatase), Amidases Angiotensin I converting enzyme (ACE), Angiotensin I converting enzyme 2 (ACE2), ADAM metallopeptidase domain 10 (ADAM10), Dipeptidyl peptidase 3 (DPP3), Insulin-degrading enzyme (IDE), Matrix metallopeptidase 1 (MMP1), Matrix metallopeptidase 12 (MMP12), Matrix metallopeptidase 13 (MMP13), Matrix metallopeptidase 14 (membrane insertion) (MMP14), Matrix metallopeptidase 2 (MMP2), Matrix metallopeptidase 3 (MMP3), Matrix metallopeptidase 7 (MMP7), Matrix metallopeptidase 8 (MMP8), Matrix metallopeptidase 9 (MMP9), Membrane metallopeptidase (NEPRILYSIN) (MME), ADAM metallopeptidase domain 17 (TACE) (ADAM17), Dipeptidyl peptidase 4 (DPP4), Dipeptidyl peptidase 8 (DPP8), Dipeptidyl peptidase 9 (DPP9), Coagulation factor Xa (Factor Xa), Coagulation factor VILA (Factor VII), Fibroblast activation protein alpha (FAP), Furin (paired basic amino acid cleaving enzyme), Granzyme A (Granzyme 1, Cytotoxic T Lymphocyte-Associated (GZMA), Serine esterase 3), Granzyme B (Granzyme 2, Cytotoxic T Lymphocyte-Associated (GZMB), Serine esterase 1), Granzyme K (Granzyme 3, Trypsin II) (GZMK), Kallikrein-1 (KLK1), Kallikrein-2 (KLK2), Plasma kallikrein (PSA,KLK3), Kallikrein-11 (KLK11), Kallikrein-13 (KLK13), Kallikrein-15 (KLK15), Matrixase (ST14), Spinesin (TMPRSSS), Plasmin (PLG), Prolyl oligopeptidase (PREP), Thrombin (F2), tPA, Plasminogen activator tissue type (PLAT), UPA, Plasminogen activator urokinase (PLAU), HtrA serine peptidase 2 (hTRA2), Caseinolytic mitochondrial matrix peptidase proteolytic subunit (CIPP / X), Constitutive proteasome chymotrypsin-like form (PSMBS, b5), Constitutive proteasome trypsin-like form (PSMB7, b7), Constitutive proteasome caspase-like form (PSMB6, b6), Immunoproteasome chymotrypsin-like form (PSMB8, LMP7), Immunoproteasome trypsin-like form (PSMB, 10 MECL1), Immunoproteasome caspase-like form (PSMB9, LMP2).

[0526] In some embodiments, P1or P2in the linker unit of the ADC of the present disclosure is specifically recognized and cleaved by Cathepsin B, for example, Val-Cit, Val-Ala, Gly-Gly-Phe-Gly, Gly-Phe-Leu-Gly.

[0527] In some embodiments, P1or P2in the linker unit of the ADC of the present disclosure is specifically recognized and cleaved by Asparaginyl endopeptidase (Legumain), for example, Ala-Ala, Ala-Ala-Asn.

[0528] In some embodiments, P1or P2in the linker unit of the ADC of the present disclosure is specifically recognized and cleaved by, for example, high concentration of Matrix Metalloproteinase 2 / 9 (MMP-2 / 9) in tumors, for example, Pro-Leu-Gly-Leu-Ala-Gly (PLGLAG), Gly-Pro-Leu-Gly-Ile-Ala-Gly-Gln (GPLGIAGQ), Gly-Pro-Val-Gly-Leu-Ile-Gly-Lys (GPVGLIGK).

[0529] In some embodiments, P1 or P2 as part of the linker unit of the ADC of the present disclosure is a cleavable peptide containing two or more (e.g. 2-12) consecutive or non-consecutive amino acids, e.g. can comprise or consist of a dipeptide, tripeptide, tetrapeptide, pentapeptide, hexapeptide, heptapeptide, octapeptide, nonapeptide, decapeptide, undecapeptide or dodecapeptide unit. Each amino acid of the peptide containing unit can be selected independently from each other from a natural amino acid or a non-natural amino acid and / or be a D- or L-isomer, with the proviso that P1 or P2 comprises a cleavable bond which, when cleaved, will initiate release of the payload. In certain embodiments, P1 or P2 consists only of natural amino acids. In other embodiments, P1 or P2 consists only of non-natural amino acids. In some embodiments, P1 or P2 consists of natural amino acids attached to non-natural amino acids. In some embodiments, P1 or P2 consists of natural amino acids attached to D-isomers of natural amino acids.

[0530] In some embodiments, each amino acid is independently L-(natural) amino acid. In another embodiment, each amino acid is independently selected from the D-isomer of the natural amino acid.

[0531] In some embodiments, P1 or P2 or the cleavable peptide contained therein has the structure of formula (P) from the N-terminus to the C-terminus: d -(P) wherein AA is an amino acid selected from alanine (Ala), arginine (Arg), aspartic acid (Asp), asparagine (Asn), histidine (His), glycine (Gly), glutamic acid (Glu), glutamine (Gln), phenylalanine (Phe), lysine (Lys), substituted lysine, leucine (Leu), serine (Ser), tyrosine (Tyr), threonine (Thr), isoleucine (lie), proline (Pro), tryptophan (Trp), valine (Val), cysteine (Cys), methionine (Met), selenocysteine, ornithine (Asn), beta-alanine (beta-Ala), citrulline (Cit) and derivatives thereof;

[0532] Preferably, AA is selected from alanine, glycine, asparagine, isoleucine, leucine, valine, phenylalanine, citrulline, glutamic acid; more preferably, AA is selected from alanine, glycine, asparagine, valine, phenylalanine, citrulline, glutamic acid;

[0533] d is an integer from 2 to 12; preferably an integer from 2 to 8, more preferably an integer from 2 to 4;

[0534] wherein each AA is connected by a peptide bond.

[0535] In some embodiments, the N-terminus of the cleavable peptide contained in P1 or P2 is attached to the branching unit W and the C-terminus is attached to the self-immolative linker A1 or A2 moiety of the linker unit.

[0536] In some embodiments, d is an integer from 2 to 8, for example, an integer from 2 to 6, 2 to 4, 2 to 3, for example, 2, 3, 4, 6, 8.

[0537] In some embodiments, -(AA) d In some embodiments, d is 2, P1 or P2 is a dipeptide, for example, a dipeptide selected from the group consisting of Ala-Ala, Ala-(D)Asp, Ala-Cit, Ala-Lys, Val-Ala, Asn-Cit, Asp-Cit, Asn-Lys, Asn-(D)Lys, Asp-Val, Cit-Ala, Cit-Asn, Cit-Asp, Cit-Cit, Cit-Lys, Cit-Ser, Cit-Val, Glu-Val, Glu-Gly, phenyl Gly-(D)Lys, His-Val, Ile-Cit, Ile-Pro, Ile-Val, Leu-Cit, Lys-Cit, Me3Lys-Pro, Met-Lys, Met-(D)Lys, Phe-Arg, Phe-Cit, Phe-Lys, Pro-(D)Lys, Ser-Cit, Trp-Cit, Val-Ala, Val-(D)Asp, NorVal-(D)Asp, Val-Cit, Val-Glu, Val-Lys, and salts thereof. In a specific embodiment, the dipeptide is Ala-Ala. In a specific embodiment, the dipeptide is Val-Cit. In another specific embodiment, the dipeptide is Val-Ala. In another specific embodiment, the dipeptide is Glu-Gly.

[0538] In some embodiments, -(AA) d- in which d is 3, P1or P2is a tripeptide, such as Gly-Gly-Gly, Gly-Gly-Arg, Phe-Lys-Gly, Leu-Lys-Gly, Leu-Leu-Gly, Glu-Val-Cit, Cit-Ala-Glu, Val-Lys-Gly, Val-Lys-Ala, Val-Gly-Gly, Val-Cit-Gly, Val-Gln-Gly, Val-Glu-Gly, Val-Lys-Gly, Val-Lys-Leu, Ala-Ala-Ala, Ala-Ala-Asn. In a particular embodiment, the tripeptide is Ala-Ala-Asn. In a particular embodiment, the tripeptide is Glu-Val-Cit. In a particular embodiment, the tripeptide is Cit-Ala-Glu.

[0539] In some embodiments, -(AA) d - in which d is 4, P1or P2is a tetrapeptide, such as Gly-Gly-Gly-Gly, Gly-Gly-Leu-Gly, Gly-Phe-Leu-Gly, Gly-Val-Lys-Gly, Ala-Leu-Ala-Leu, Gly-Phe-Leu-Gly, Ala-Leu-Ala-Leu, Gly-Gly-Phe-Gly, Val-Lys-Gly-Gly. In a particular embodiment, the tetrapeptide is Gly-Phe-Leu-Gly. In another particular embodiment, the tetrapeptide is Gly-Gly-Phe-Gly.

[0540] In some embodiments, -(AA) d - in which d is 6 or 8, P1or P2is a hexapeptide or an octapeptide, such as Pro-Leu-Gly-Leu-Ala-Gly (PLGLAG), Gly-Pro-Leu-Gly-Ile-Ala-Gly-Gln (GPLGIAGQ), Gly-Pro-Val-Gly-Leu-Ile-Gly-Lys (GPVGLIGK).

[0541] Preferably, the above specifically exemplified peptides are linked at the N-terminus to the branching unit W and at the C-terminus to the self-immolative linker A1or A2of the linker unit.

[0542] In some embodiments, P1or P2is a peptide comprising a substituted lysine, such as a dipeptide, a tripeptide, a tetrapeptide, a hexapeptide or an octapeptide. In one embodiment, the substituted lysine is:

[0543] in which R 15 and R15 independently selected from H, C 1-6 alkyl, -CO-NH2, -CONH(C 1-6 alkyl) and -CONH(C 1-6 alkyl)2, wherein the alkyl groups are optionally substituted with a group selected from halogen, C 1-6 alkoxy, C 1-6 haloalkyl and C 3-6 cycloalkyl.

[0544] In preferred embodiments, P1or P2is selected from the following peptides:

[0545] wherein the carbonyl end is connected to the self-immolative linker A1or A2and the N-terminus is connected to the branching unit W.

[0546] A1or A2— self-immolative linker

[0547] The self-immolative linker A1or A2in the linker unit L of the ADCs of the present disclosure can be absent, i.e. the cleavable linker is directly covalently linked to the payload, or it can be a functional group that facilitates the linkage of the cleavable linker to the payload, or it is a functional group that provides an additional structural component to further facilitate the release of the payload from the rest of the ADC.

[0548] In some embodiments, the self-immolative linker A1and / or A2of the ADCs of the present disclosure is absent, i.e. the cleavable linker is directly covalently linked to the payload, e.g. the carboxyl end of the cleavable linker is linked to an amino group or OH present in the payload in an amide bond or an ester bond.

[0549] In some embodiments, the self-immolative linker A1and / or A2of the ADCs of the present disclosure is a functional group that facilitates the linkage of the cleavable linker to the payload, or it can provide an additional structural component to further facilitate the release of the payload from the ADC. Specifically, such A1or A2may be selected from:

[0550] wherein,

[0551] The site marked with an * is the point of linkage to the payload, the bond shown with a wavy line is the linkage to the cleavable linker;

[0552] each occurrence of Y1is independently selected from NH or O;

[0553] each occurrence of R 16 is independently selected from H and -C 1-6 alkyl, preferably H or C 1-3 alkyl, more preferably H or methyl;

[0554] each occurrence of R 17each independently selected from the group consisting of H, -NO2, -NH2, -CF3.

[0555] In some embodiments, R 16 is H. In other embodiments, R 16 is -C 1-6 alkyl, preferably C 1-3 alkyl, more preferably methyl. Preferably R 16 is H.

[0556] In some embodiments, R 17 is H.

[0557] In some embodiments, A1or A2is selected from

[0558] In some embodiments, A1is selected from and A2is selected from

[0559] In some embodiments, as A1or A2 Examples of include

[0560] In some embodiments, as A1or A2 Examples of include

[0561] In some embodiments, as A1or A2 is

[0562] In preferred embodiments, A1or A2is selected from

[0563] S1or S2— solubilizing unit

[0564] In the ADC of the present disclosure, the solubilizing unit S1or S2, when present, is linked to the self-immolative linker A1or A2. In the ADC of the present disclosure, the introduction of the solubilizing group in the linker unit helps to improve the hydrophilicity of the conjugate chain, increase the loading rate to the theoretical maximum value, while improving the solubility and purity of the conjugate, reducing the degree of aggregation, improving the drugability of the conjugate and ultimately improving the effect of inhibiting the proliferation of tumor cells.

[0565] In some embodiments, the ADC of the present disclosure does not contain S1and S2. In some embodiments, the ADC of the present disclosure contains S1and does not contain S2. In some embodiments, the ADC of the present disclosure contains only S2.

[0566] In embodiments of the ADC of the disclosure comprising S1and / or S2, it can be attached to A1and / or A2in the ADC of the disclosure and both A1and A2are selected from S1or S2may be attached to the phenyl ring in which it is located, i.e.

[0567] In particular embodiments, S1or S2has the structure of formula (S): (S), wherein

[0568] T’ is selected from -C(R a )2-, -O-, -NR a - or is absent;

[0569] M’ is selected from -CO-, -O-, -NR a - or is absent;

[0570] Z’ is selected from a glycosyl group or a derivative thereof, and a hydrophilic peptide comprising ;

[0571] R a is selected from H or C 1-6 alkyl;

[0572] subunit is selected from a natural amino acid residue and a non-natural amino acid residue;

[0573] n’ is an integer from 0 to 4, for example 0-2, 1-4, 1-2, 2-4;

[0574] m is an integer from 0 to 20, for example 0-8, 0-6, 0-4, 0-2, 1-20, 1-10, 2-10, 2-8, 2-6, 2-4, 4-14, 4-12, 4-10, 5-10, 6-10, 6-12, 8-10, 8-14.

[0575] In some embodiments of formula (S), m is an integer from 0 to 10, for example 0-8, 0-6, 0-4, 0-2, 2-10, 2-8, 2-6, 2-4. In other embodiments of formula (S), m is an integer from 1-20, 1-10, 2-10, 2-8, 2-6, 2-4, 4-14, 4-12, 4-10, 5-10, 6-10, 6-12, 8-10, 8-14, for example 4-14, 4-12, 6-12, 4-10 or 5-10.

[0576] In some embodiments of formula (S), T is -C(R a )2-, for example methylene.

[0577] In some embodiments of formula (S), T is -O-.

[0578] In some embodiments of formula (S), T is -NR a - such as -NH-.

[0579] In some embodiments of formula (S), T is absent.

[0580] In some embodiments of formula (S), M is -CO-.

[0581] In some embodiments of formula (S), M is -O-.

[0582] In some embodiments of formula (S), M is -NR a - such as -NH-.

[0583] In some embodiments of formula (S), M is absent.

[0584] In some embodiments of formula (S), R a is H, in other embodiments of formula (S), R a is C 1-6 alkyl, such as C 1-3 alkyl, preferably methyl.

[0585] In some embodiments of formula (S), S1and / or S2in the ADC of the present disclosure, when present, Z' is directly attached to the phenyl ring of A1or A2, i.e. both T' and M' are absent, and n' is 0, as shown in In particular such embodiments, Z' is, for example, a sugar group or derivative thereof as generally or specifically defined herein, attached to the phenyl ring via a glycosidic bond, a monosaccharide, a disaccharide or derivative thereof, more preferably a five- or six-carbon sugar or a uronic acid, amino sugar, acylated amino sugar, amino uronic acid or acylated amino uronic acid derivative thereof, and even more preferably glucose, mannose, galactose or a derivative thereof.

[0586] In some embodiments of formula (S), S1and / or S2in the ADC of the present disclosure, when present, Z' is attached to the phenyl ring of A1or A2via a moiety in formula (S) wherein both T' and M' are present, which moiety can be selected from or T' is present and M' is absent, which moiety can be selected from or T' is absent and M' is present, which moiety can be selected from wherein n' is as defined above, preferably 1-2, and R a is preferably H.

[0587] In some embodiments of formula (S), Z' is a sugar group or derivative thereof.

[0588] In some embodiments of formula (S), Z' is a glycosyl group or a derivative thereof and attached via a glycosidic bond, or Z is an amino sugar and attached via an amino group, then M' in the above shown may be absent, e.g. is For example For example or M is -CO-, e.g. is For example For example In this case Z' is an -O-sugar residue, -NH-sugar residue or a derivative thereof.

[0589] In some embodiments of formula (S), Z' is a uronic acid or a derivative thereof and attached via a carboxyl group to M, then M' in the above shown may be -O or -NR-, in which case Z' is a -CO-uronic acid residue or a derivative thereof.

[0590] In the ADCs of the present disclosure, the glycosyl group or derivative thereof in the antibody linker or solubilizing unit is selected from a monosaccharide, disaccharide, oligosaccharide or polysaccharide group or derivative thereof, preferably a monosaccharide or disaccharide group or derivative thereof, more preferably a five-carbon monosaccharide, a six-carbon monosaccharide or a disaccharide formed by linking thereof, or a derivative thereof.

[0591] In some embodiments, the glycosyl group in the ADCs of the present disclosure can be attached to the solubilizing unit via any of its free hydroxyl groups, or derivatized amino or carboxyl groups, e.g. via the OH at position 1 of the sugar unit, the carboxyl group of the uronic acid, the amino group of the amino sugar.

[0592] The above monosaccharides and derivatives thereof include the D-configuration, L-configuration, racemate (DL) and meso, preferably the D-configuration, and also any optically active forms ((+), (-), (±)). The monosaccharides and derivatives thereof described in the present disclosure include chain isomers, cyclic isomers or mixtures thereof, wherein the cyclic forms include the alpha anomer and beta anomer or mixtures thereof, and for example include pyranose forms or furanose forms.

[0593] In some embodiments, the glycosyl group in the ADCs of the present disclosure is attached to the solubilizing unit via a glycosidic bond, e.g. via a glycosidic bond at position 1 of the sugar unit, which can be in the alpha form, or in the beta form, or mixtures thereof.

[0594] In preferred embodiments, the monosaccharide groups in the ADCs of the present disclosure are selected from glucose, mannose, galactose, or their respective uronic acid, amino sugar, acylated amino sugar, amino sugar uronic acid, or acylated amino sugar uronic acid forms, such as glucose, galactose, mannose, glucosamine, galactosamine, mannosamine, galacturonic acid, glucuronic acid, manuronic acid, glucosaminuronic acid, galactosaminuronic acid, mannosaminuronic acid, acetylamino galactose, acetylamino glucose, acetylamino mannose, acetylamino galacturonic acid, acetylamino glucuronic acid, acetylamino manuronic acid; further preferred are D-glucose, D-galactose, D-mannose, D-glucosamine, D-galactosamine, D-mannosamine, D-galacturonic acid, D-glucuronic acid, D-mannuronic acid, D-glucosaminuronic acid, D-galactosaminuronic acid, D-mannosaminuronic acid, 2-acetylamino-2-deoxy-D-galactose, 2-acetylamino-2-deoxy-D-glucose, 2-acetylamino-2-deoxy-D-mannose, 2-acetylamino-2-deoxy-D-galacturonic acid, 2-acetylamino-2-deoxy-D-glucuronic acid, 2-acetylamino-2-deoxy-D-mannuronic acid, more preferred are the monosaccharides or their derivatives shown in Table 1 below:

[0595] Preferred disaccharide groups suitable for use in the ADCs of the present disclosure include lactose or derivatives thereof, maltose or derivatives thereof, sucrose or derivatives thereof, including alpha and beta anomeric forms thereof, wherein the derivative forms are, for example, forms in which either monosaccharide group of the disaccharide is a uronic acid, amino sugar, acylated amino sugar, amino sugar uronic acid, acylated amino sugar uronic acid, or combinations thereof, such as D-lactose, D-maltose, D-sucrose, or their respective acetylamino (e.g., 2-acetylamino) and / or 6-carboxy derivatives; specific examples include, but are not limited to, those shown in Table 2 below:

[0596] wherein the dashed line at the 1 -position of the sugar unit indicates that the configuration of the glycosidic linkage can be either alpha or beta, or a mixture thereof.

[0597] In some embodiments, the solubilizing saccharide groups in the ADCs of the present disclosure are selected from glucose, mannose, galactose, lactose, maltose, sucrose, or derivatives thereof, with the derivatives preferably being their respective uronic acid, amino sugar, acylated amino sugar, amino sugar uronic acid, and / or acylated amino sugar uronic acid forms; specific examples are shown in the tables above.

[0598] In some embodiments of Formula (S), Z' is wherein R a and m have the values defined above in the general or preferred embodiments.

[0599] In some of the above embodiments of formula (S), Z' is a hydrophilic peptide comprising as generally, specifically or preferably defined above for formula (G) in the section "G- antibody linkers". In preferred embodiments, the hydrophilic peptide of formula (S) is, for example, a polyarginine comprising 4 to 14 units or 4 to 10, 5 to 10 units, more preferably 4 to 12, 6 to 12 units or 4 to 10, 5 to 10 units, connected via the carboxy terminus or a polyarginine comprising 4 to 14 units or 4 to 10, 5 to 10 units, more preferably 4 to 12, 6 to 12 units or 4 to 10, 5 to 10 units, connected via the amino terminus (preferably ), wherein R is as defined above, including but not limited to the residues carried by the amino group of the various amino acids listed herein for hydrophilic peptides, for example R can be R a ; R a is selected from H or -C 1-6 alkyl, preferably -CH3; for example the fragment indicated in square brackets is a polyomithine, polyarginine, polyglycine comprising 4 to 14 units or 4 to 10, 5 to 10 units, more preferably 4 to 12, 6 to 12 units or 4 to 10, 5 to 10 units.

[0600] In some of the above embodiments of formula (S), Z' is a hydrophilic peptide comprising , selected from (preferably ), wherein R is as defined above, including but not limited to the residues carried by the amino group of the various amino acids listed herein for hydrophilic peptides, for example R can be R a ; R a is selected from H or -C 1-6 alkyl, preferably H or -CH3, more preferably -CH3; for example the fragment indicated in square brackets is a polyomithine, polyarginine, polyglycine comprising 4 to 14 units or 4 to 10, 5 to 10 units, more preferably 4 to 12, 6 to 12 units or 4 to 10, 5 to 10 units.

[0601] In some specific embodiments of formula (S), Z' is selected from a glycosyl group or derivative thereof and a hydrophilic peptide comprising ; wherein the glycosyl group or derivative thereof is preferably glucose, mannose, galactose, lactose, maltose, sucrose or a uronic acid, amino sugar, acylated amino sugar, amino uronic acid or acylated amino uronic acid derivative of each thereof, more preferably glucose, mannose, galactose or a uronic acid, amino sugar, acylated amino sugar, amino uronic acid or acylated amino uronic acid derivative of each thereof, and wherein the hydrophilic peptide is preferably (preferably ), wherein R is as defined above, including but not limited to the residues carried by the amino group of the various amino acids listed herein for hydrophilic peptides, for example R can be R a ; R a is selected from H or -C 1-6Alkyl group, preferably H or -CH3, more preferably -CH3; preferably, the segment indicated in square brackets is polysarcosine, polyarginine, or polyglycine containing 4-14 units or 4-10 or 5-10 units, preferably polysarcosine containing 4-12 or 6-12 units or 4-10 or 5-10 units.

[0602] In some specific implementations of formula (S), formula (S) In this context, T' is selected from -C(R) a )2-、-O-、-NR a -, preferably -O-, M is -CO-, for example Where R a H or -C 1-3 Alkyl group, and Z' is Where R is defined above, it includes, but is not limited to, the amino group residues of the various amino acids listed in this article for hydrophilic peptides. For example, R could be R a ;R a Selected from H or -C 1-6 Alkyl group, preferably -CH3, for example, Z is polysarcosine, polyarginine, or polyglycine containing 4-14 units or 4-10 or 5-10 units, more preferably polysarcosine containing 4-12 or 6-12 units or 4-10 or 5-10 units; or T' is selected from -C(R a )2-、-O-、-NR a -, preferably -O-, M does not exist, for example Z' is selected from glucose, mannose, galactose, lactose, maltose, sucrose, or their respective uronic acids, amino sugars, acylated amino sugars, aminouronic acids, or derivatives of acylated aminouronic acids, preferably glucose, mannose, galactose, or their respective derivatives; wherein R a H or -C 1-3 Alkyl group, n' is 1 to 2.

[0603] Self-decomposing linker fragments carrying solubilizing units

[0604] The connecting subunits of the ADC disclosed herein include structural segments that are connected as appropriate to any combination of the self-decomposing connecting units A1 or A2 as defined above in general or specific terms and the solubilizing units S1 or S2 as defined above in general or specific terms.

[0605] In some specific implementation plans,

[0606] A1 and A2 are both selected from Preferred

[0607] S1 or S2 is attached to the benzene ring of A1 or A2, and is wherein T' is selected from -C(R a )2-, -O-, -NR a - or is absent, M' is selected from -CO-, -O-, -NR a - or is absent, n' is an integer from 0 to 4, R a is H or C 1-6 alkyl;

[0608] Z' is a monosaccharide or disaccharide group or a derivative thereof, for example selected from glucose, mannose, galactose, lactose, maltose, sucrose or a uronic acid, amino sugar, acylated amino sugar, amino uronic acid or acylated amino uronic acid derivative form, preferably a monosaccharide glucose, mannose, galactose or a respective indicated derivative form thereof; as generally or specifically indicated above; or

[0609] Z' is a hydrophilic peptide comprising as generally or specifically defined above for formula (S), preferably

[0610] In further specific embodiments, S1or S2is for example and Z' is a monosaccharide or disaccharide and or a derivative thereof as generally or specifically defined herein linked by an alpha or beta glycosidic bond. Examples of self-immolative linkers A1or A2carrying a saccharide group or derivative thereof include, but are not limited to:

[0611] The alpha / beta indicated in the above specific examples for the bond at position 1 of the saccharide unit means that the configuration of this glycosidic bond can be either alpha or beta, or a mixture thereof.

[0612] In further specific embodiments, S1or S2is wherein T' is selected from -C(R a )2-, -O- or -NR a -; M' is selected from -CO-; n is 1 to 4, for example 1-2; R a is H or C 1-6 alkyl; Z is a hydrophilic peptide comprising as generally or specifically defined above for formula (S), preferably wherein R is as defined above, including but not limited to the residues carried by the various amino acids listed herein for the hydrophilic peptide, for example R can be R a , R a is selected from H or -C 1-6Alkyl group, preferably -CH3, for example, the fragment shown in square brackets is polysarcosine, polyarginine, or polyglycine containing 4-14 units or 4-10, 5-10 units, more preferably polysarcosine containing 4-12, 6-12 units or 4-10, 5-10 units. Examples of self-decomposing linkers A1 or A2 carrying hydrophilic peptides include, but are not limited to:

[0613] Implementation scheme of connector unit L

[0614] It should be noted that the connector unit L of the ADC of this disclosure includes any combination of the general or specific or preferred definition of any one of the components of the connector unit as described above and the general or specific or preferred definition of the other one or more components.

[0615] The connector unit L in the ADC of this disclosure has the structure of formula (III) and its various sub-formulas described above, and preferably has the following structure.

[0616] G, W, P1, P2, A1, A2, and S2 are each defined as generally, specifically, or preferably as described above for each part.

[0617] In some specific implementations, the connector units of the ADC disclosed herein are in formulas (III-2) and (III-3).

[0618] G is Preferred The asterisk-marked end connects to the antibody, and the wavy line end connects to the property regulation unit E or the branching unit W; the alkylene group is optionally replaced by the Bu substituent of formula (G) as generally, specifically, or preferably defined in the "G-antibody linker" section above, and preferably by... Replacement, where T0 is -C 1-3 alkylene, preferably methylene, Z is Where R, as defined above, includes, but is not limited to, the amino group residues of the various amino acids listed in this article for hydrophilic peptides. For example, R could be R a ;R a Selected from H or -C 1-6 Alkyl group, preferably -CH3, the segment shown in square brackets is polysarcosine, polyarginine, or polyglycine containing 4-14 units or 4-10 or 5-10 units, preferably polysarcosine containing 4-12 or 6-12 units or 4-10 or 5-10 units.

[0619] W is Connected to the antibody linker G via the N-terminus;

[0620] P1or P2is a cleavable peptide having the structure of formula (P) from N- to C-terminus: -(AA) d - wherein AA is selected from alanine, glycine, asparagine, isoleucine, leucine, valine, phenylalanine, citrulline, glutamic acid; preferably AA is selected from alanine, glycine, asparagine, valine, phenylalanine, citrulline, glutamic acid; d is an integer from 2 to 8, more preferably an integer from 2 to 4; wherein each AA is connected by a peptide bond; more preferably selected from more preferably

[0621] A1or A2is selected from wherein R 16 is H and R 17 is H, Y1is selected from NH or O; preferably wherein one end of the asterisk is connected to the payload and one end of the wavy line is connected to P1or P2;

[0622] S2is of formula (S) connected to the phenyl ring of A2, wherein T’ is selected from -C(R a )2-, -O-, -NR a - or is absent, preferably -O-, M’ is selected from -CO-, -O-, -NR a - or is absent, preferably -CO- or is absent, n is an integer from 0 to 4, preferably 1-2, R a is H or C 1-6 alkyl;

[0623] Z’ is a monosaccharide or disaccharide group or a derivative thereof; or

[0624] Z’ is a hydrophilic peptide comprising , preferably wherein R is as defined above, including but not limited to residues carried by the amino groups of the various amino acids listed herein for the hydrophilic peptide, for example R can be R a ; R a is selected from H or -C 1-6 alkyl, preferably -CH3; for example the fragment shown in square brackets is a polymuscin, polyarginine, polyglycine comprising 4-14 units or 4-10, 5-10 units, more preferably a polymuscin comprising 4-12, 6-12 units or 4-10, 5-10 units.

[0625] In some embodiments of formula (III-2) or (III-3), A1is for example A2is selected from for example

[0626] In some embodiments of formula (III-2), A2is For example S2carrying thereon a S2of formula (S) as generally, specifically or preferably defined herein, preferably comprising Z' being a monosaccharide or disaccharide or derivative thereof, or S2comprising Z' being a hydrophilic peptide as generally, specifically or preferably defined above.

[0627] In specific embodiments of formula (III-2) or (III-3), the monosaccharide or disaccharide or derivative thereof as Z' is as generally, specifically or preferably indicated above, preferably glucose, mannose, galactose, lactose, maltose, sucrose, more preferably glucose, mannose, galactose, or a uronic acid, amino sugar, acylated amino sugar, amino uronic acid and / or acylated amino uronic acid derivative form thereof.

[0628] Thus, the linker unit of formula (III-2) or (III-3) can have the general formula as indicated in Table 3 below:

[0629] wherein each variable or fragment has the general or specific or preferred definition as given above for the respective component, i.e. the present disclosure also encompasses linker units wherein each variable or fragment in the above formula has the general or specific or preferred definition as given above for the respective component; in particular, the fragments corresponding to formula (G) and formula (S) in the above general formula have the general, specific or preferred definition as given above for the respective component, wherein Z or Z' is preferably a glycosyl group or derivative thereof (preferably a preferred monosaccharide or derivative thereof as defined herein) or a hydrophilic peptide (preferably a hydrophilic peptide as defined above).

[0630] In specific embodiments, the linker unit L fragment of the ADCs of the present disclosure is selected from the structures as indicated in Table 4 below,

[0631] It is noted that the present disclosure encompasses not only the above generally, specifically or preferably defined linker units as components of the ADCs of the present disclosure, but also the above generally, specifically or preferably defined linker units per se, as well as all conjugates containing the structure of the linker unit.

[0632] i.e. in another aspect, the present disclosure relates to the above generally, specifically or preferably defined linker units, preferably those containing a hydrophilic peptide and / or a glycosyl group or derivative thereof.

[0633] In another aspect, the present disclosure relates to conjugates comprising a linker unit according to the above general, specific or preferred definitions, preferably those comprising a linker unit with a hydrophilic peptide and / or a glycosyl or derivative thereof.

[0634] Payload-linker unit fragment

[0635] The linker unit L of the ADCs of the present disclosure comprises a payload-linker unit fragment consisting of any combination of the general or specific or preferred definitions for the linker unit and the general or specific or preferred definitions for D1 or D2.

[0636] Based on the above, the present disclosure is a payload-linker unit fragment according to formula (X) or (X-1) having the formula

[0637] For example

[0638] wherein:

[0639] the wavy line indicates the linkage to a targeting ligand such as an antibody or antigen binding fragment thereof;

[0640] D1 is a compound of formula (II) and each of its respective subformulae as defined herein, linked via an amino group at any one of the -SH, B1 or B2 base or an -OH at the sugar ring to the linker unit, preferably more specifically a fragment of formula (II) subformulae linked via

[0641] furthermore

[0642] wherein the asterisk indicates the point of attachment to the linker unit, B1, B2, R1, R1', R2, R2' have the meaning as generally or specifically or preferably defined above for the moiety D1, and the D1 molecule has the meaning as generally, preferably or specifically defined above for D1;

[0643] D2 is a small molecule compound as generally, preferably or specifically defined above for D2;

[0644] The linker unit moiety has the structure of formula (III), (III-1), (III-2), (III-3), (III-4), (III-5), (III-6), (III-7), respectively, preferably the structure of formula (III-2) or (III-3) as defined in the “Embodiments of linker unit L” section herein, more preferably the structure of (III-2-1), (III-2-2), (III-3-1), (III-3-2), (III-3-3), or (III-3-4) as defined above, and even more preferably the exemplary structure of formula (III-2-1), (III-2-2), (III-3-3), or (III-3-4) as defined above.

[0645] In some embodiments of formula (IV) and the respective subformulae thereof,

[0646] B1is adenine optionally substituted with X wherein X is selected from H, Cl, F, or -NHC 1-6 alkyl; or guanine optionally substituted with R b wherein R b is selected from -C 1-6 alkyl;

[0647] B2is guanine

[0648] R1and R1are both H, or one is H and the other is F, or one is H and the other is OH;

[0649] R2and R2are both H, or one is H and the other is F, or one is H and the other is OH;

[0650] In some embodiments, in formula (IV), B1is, for example, preferably B2is guanine In a particular such embodiment, R1and R1are both H, or one is H and the other is F, or one is H and the other is OH. In a further particular such embodiment, one of R2and R2is H and the other is OH.

[0651] Exemplary payload-linker unit fragments of the present disclosure are, for example, but not limited to, PL-3 to PL-59 prepared and characterized in the Examples section, or a stereoisomer, tautomer, stable isotopic variant, pharmaceutically acceptable salt, or solvate thereof.

[0652] ​It is noted that the present disclosure encompasses not only the payload-linker unit fragments as defined generally, specifically or preferably above as components of the ADCs of the present disclosure, but also the payload-linker unit fragments as defined generally, specifically or preferably above per se, as well as all conjugates containing such payload-linker unit fragments.

[0653] That is, in another aspect, the present disclosure relates to a payload-linker unit fragment compound as defined generally, specifically or preferably above, represented as: Specifically For example

[0654] wherein each moiety and each variable within each moiety has the respective general, specific or preferred definition above, the present disclosure encompasses the payload-linker unit fragment compounds formed by any combination of the general, specific or preferred definition of said any moiety and variable therein with the general, specific or preferred definition of one or more other moieties and variables therein;

[0655] Preferred are those payload-linker unit fragment compounds containing a hydrophilic peptide and / or a glycosyl group or derivative thereof as defined generally, specifically or preferably herein.

[0656] In another aspect, the present disclosure relates to conjugates comprising a payload-linker unit fragment as defined generally, specifically or preferably above, preferably those containing a hydrophilic peptide and / or a glycosyl group or derivative thereof.

[0657] The ADCs of the present disclosure

[0658] The ADCs of the present disclosure include the technical solutions formed by any combination of the general or specific or preferred definition of any one component with the general or specific or preferred definition of one or more other components.

[0659] Based on the above, the ADCs of the present disclosure of formula (X-1) can be represented as:

[0660] Specifically

[0661] For example

[0662] or a pharmaceutically acceptable salt, ester, isomer, solvate, prodrug or isotopically-labeled form thereof;

[0663] wherein each component of the linker unit, the linker unit itself, D1, D2 are defined as above according to the respective general, specific or preferred definitions; q has the values defined above for formula (X) or (X-1), specifically represents an average DAR value of 1 to 10 or a range between any two of the values 1 to 10, preferably 1 to 8 or a range between any two of the values 1 to 8, for example about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1 to 2, 1 to 3, 1 to 4, 1 to 5, 1 to 6, 1 to 7, 1 to 8, 1 to 9, 1 to 10, 2 to 10, 2 to 8, 2 to 6, 2 to 4, 3 to 10, 3 to 8, 4 to 6, 4 to 8, 4 to 10, 6 to 8, or 6 to 10; Ab is an antibody or antigen binding fragment thereof that binds to a tumor-specific antigen or a tumor-associated antigen, as generally, specifically or preferably defined above for the Ab moiety.

[0664] In some preferred embodiments, q represents an average DAR of about 3. In some preferred embodiments, q represents an average DAR of about 6. In some preferred embodiments, q represents an average DAR of about 8.

[0665] In some preferred embodiments, the antigen bound by Ab in the ADC of the present disclosure is selected from the group consisting of HER2, KIT, FOLR1, CD276, PD-L1, NECTIN4, Mesothelin, MUC1, GCPII, BCMA, cMet, RPR1, CD22, CD19, TOP1, Claudin 18.2, EGFR, Trop-2; preferably from the group consisting of HER2, EGFR, Claudin 18.2 and Trop-2.

[0666] In a more preferred group of embodiments, Ab in the ADC of the present disclosure is an antibody or antigen binding fragment thereof that specifically binds to HER2.

[0667] In this more preferred group of embodiments, Ab in the ADC of the present disclosure comprises 3 heavy chain complementarity determining regions (HCDRs) and 3 light chain complementarity determining regions (LCDRs), wherein:

[0668] HCDR1 comprises or consists of the amino acid sequence of SEQ ID NO: 6,

[0669] HCDR2 comprises or consists of the amino acid sequence of SEQ ID NO: 7,

[0670] HCDR3 comprises or consists of the amino acid sequence of SEQ ID NO: 8,

[0671] LCDR1 comprises or consists of the amino acid sequence of SEQ ID NO: 3,

[0672] LCDR2 comprises or consists of the amino acid sequence of SEQ ID NO: 4, and

[0673] LCDR3 comprises or consists of the amino acid sequence of SEQ ID NO: 5.

[0674] In a more preferred embodiment of this group, the Ab in the ADC of the present disclosure comprises a heavy chain variable region and a light chain variable region, wherein the heavy chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 10, and wherein the light chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 9.

[0675] In a more preferred embodiment of this group, the Ab in the ADC of the present disclosure comprises:

[0676] (a) a heavy chain comprising the amino acid sequence of SEQ ID NO: 2, and

[0677] (b) a light chain comprising the amino acid sequence of SEQ ID NO: 1.

[0678] In a more preferred embodiment of this group, the Ab in the ADC of the present disclosure is Trastuzumab.

[0679] In another more preferred embodiment of this group, the Ab in the ADC of the present disclosure is an antibody or antigen binding fragment thereof that specifically binds to Trop-2.

[0680] In a more preferred embodiment of this group, the Ab in the ADC of the present disclosure comprises 3 heavy chain complementarity determining regions (HCDRs) and 3 light chain complementarity determining regions (LCDRs), wherein:

[0681] HCDR1 comprises or consists of the amino acid sequence of SEQ ID NO: 18,

[0682] HCDR2 comprises or consists of the amino acid sequence of SEQ ID NO: 19,

[0683] HCDR3 comprises or consists of the amino acid sequence of SEQ ID NO: 20,

[0684] LCDR1 comprises or consists of the amino acid sequence of SEQ ID NO: 15,

[0685] LCDR2 comprises or consists of the amino acid sequence of SEQ ID NO: 16, and

[0686] LCDR3 comprises or consists of the amino acid sequence of SEQ ID NO: 17.

[0687] In this group of more preferred embodiments, the Ab in the ADC of the present disclosure comprises a heavy chain variable region and a light chain variable region, wherein the heavy chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 22, and wherein the light chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 21.

[0688] In this group of more preferred embodiments, the Ab in the ADC of the present disclosure comprises:

[0689] (a) a heavy chain comprising the amino acid sequence of SEQ ID NO: 14, and

[0690] (b) a light chain comprising the amino acid sequence of SEQ ID NO: 13.

[0691] In this group of more preferred embodiments, the Ab in the ADC of the present disclosure is Sacituzumab.

[0692] In another group of more preferred embodiments, the Ab in the ADC of the present disclosure is an antibody or antigen-binding fragment thereof that specifically binds Claudin 18.2.

[0693] In this group of more preferred embodiments, the Ab in the ADC of the present disclosure comprises 3 heavy chain complementarity determining regions (HCDRs) and 3 light chain complementarity determining regions (LCDRs), wherein:

[0694] HCDR1 comprises or consists of the amino acid sequence of SEQ ID NO: 29,

[0695] HCDR2 comprises or consists of the amino acid sequence of SEQ ID NO: 30,

[0696] HCDR3 comprises or consists of the amino acid sequence of SEQ ID NO: 31,

[0697] LCDR1 comprises or consists of the amino acid sequence of SEQ ID NO: 26,

[0698] LCDR2 comprises or consists of the amino acid sequence of SEQ ID NO: 27, and

[0699] LCDR3 comprises or consists of the amino acid sequence of SEQ ID NO: 28.

[0700] In this group of more preferred embodiments, the Ab in the ADC of the present disclosure comprises a heavy chain variable region and a light chain variable region, wherein the heavy chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 33, and wherein the light chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 32.

[0701] In this group of more preferred embodiments, the Ab in the ADC of the present disclosure comprises:

[0702] (a) a heavy chain comprising the amino acid sequence of SEQ ID NO: 25, and

[0703] (b) a light chain comprising the amino acid sequence of SEQ ID NO: 24.

[0704] In this group of more preferred embodiments, the Ab in the ADC of the present disclosure is Zolbetuximab.

[0705] In another group of more preferred embodiments, the Ab in the ADC of the present disclosure is an antibody or antigen-binding fragment thereof that specifically binds to EGFR.

[0706] In this group of more preferred embodiments, the Ab in the ADC of the present disclosure comprises 3 heavy chain complementarity determining regions (HCDRs) and 3 light chain complementarity determining regions (LCDRs), wherein:

[0707] HCDR1 comprises or consists of the amino acid sequence of SEQ ID NO: 40,

[0708] HCDR2 comprises or consists of the amino acid sequence of SEQ ID NO: 41,

[0709] HCDR3 comprises or consists of the amino acid sequence of SEQ ID NO: 42,

[0710] LCDR1 comprises or consists of the amino acid sequence of SEQ ID NO: 37,

[0711] LCDR2 comprises or consists of the amino acid sequence of SEQ ID NO: 38, and

[0712] LCDR3 comprises or consists of the amino acid sequence of SEQ ID NO: 39.

[0713] In this group of more preferred embodiments, the Ab in the ADC of the present disclosure comprises a heavy chain variable region and a light chain variable region, wherein the heavy chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 44, and wherein the light chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 43.

[0714] In this group of more preferred embodiments, the Ab in the ADC of the present disclosure comprises:

[0715] (a) a heavy chain comprising the amino acid sequence of SEQ ID NO: 36, and

[0716] (b) a light chain comprising the amino acid sequence of SEQ ID NO: 35.

[0717] In this group of more preferred embodiments, the Ab in the ADC of the present disclosure is Cetuximab.

[0718] It is noted that the ADC of the present disclosure encompasses any combination of any embodiment of the present disclosure generally or specifically defined for the D1 or D2 unit, any embodiment of the present disclosure generally or specifically defined for the linker unit L, and any embodiment of the present disclosure generally or specifically defined for the antibody Ab.

[0719] In particularly preferred embodiments, specific examples of the ADC of the present disclosure include:

[0720] pharmaceutically acceptable salts, esters, isomers, prodrugs, solvates, or isotopic variants thereof,

[0721] wherein q represents an average DAR value of 1-20, preferably an average DAR value of 1 to 10, 1 to 8, for example about 2, 3, 4, 5, 6, 7, 8, 9, 10, about 1 to 2, 1 to 3, 1 to 4, 1 to 5, 1 to 6, 1 to 7, 1 to 8, 1 to 9, 1 to 10, 2 to 10, 2 to 8, 2 to 6, 2 to 4, 3 to 10, 3 to 8, 4 to 6, 4 to 8, 4 to 10, 6 to 8, or 6 to 10.

[0722] In some preferred embodiments, q represents an average DAR of about 3. In some preferred embodiments, q represents an average DAR of about 6. In some preferred embodiments, q represents an average DAR of about 8.

[0723] II: Benefits of the ADC of the present disclosure

[0724] The ADC according to the present disclosure has at least one or more of the following advantages:

[0725] Targeting tumor cells, activating the STING innate immune pathway in tumor cells, killing tumor cells, while the CDN decomposes to release pre-designed cytotoxic subunit units, further killing tumor cells, conferring high-efficiency tumor killing effect in animal body, and providing tumor marker fragments for the acquired immune system, conferring immune memory to the body, consolidating long-term immune effect;

[0726] Significantly promote the distribution of ADC to the tumor environment compared with the blood circulation distribution of CDN, effectively limit the premature release of CDN load in plasma, reduce off-target toxicity;

[0727] No obvious aggregation phenomenon, can realize high drug loading, DAR can be as high as 8;

[0728] The ADC-CDN conjugate can effectively protect CDN from being hydrolyzed by phosphatase in blood, thereby greatly improving the blood circulation stability of the drug CDN;

[0729] The ADC-CDN is endocytosed by cancer cells with high expression of corresponding antigens under the guidance of antibodies, and can provide rapid and effective release of CDN in tumor cells, and the CDN decomposes and releases cytotoxic molecules after playing the function of STING agonist;

[0730] The CDN gets phosphorylated fragment molecules after intracellular decomposition, which crosses the key activation step of traditional cytotoxic molecules, improving drug efficacy;

[0731] The phosphorylated fragment molecules obtained after intracellular decomposition of CDN are not easy to be pumped out of cancer cells, reducing drug resistance;

[0732] The use of ligation technology to introduce a second payload allows the fusion of payloads with different mechanisms of action into a single ADC, not only delivering antitumor drugs to target tissues, but also ensuring that different drugs can reach the same cell, thereby efficiently achieving drug synergy, reducing the effective dose of drugs, and reducing toxicity;

[0733] Adding a solubilizing unit in the linker unit can promote the conjugation reaction, increase the DAR value, and reduce ADC aggregation, thereby facilitating the increase of ADC activity;

[0734] The dual-payload ADC in animal models showed significantly improved antitumor activity compared with single-payload 1 ADC and single-payload 2 ADC, and showed superadditive effects beyond the two single-payload ADCs, i.e. synergistic effect was achieved;

[0735] Show a wide safety window in all (many) in vivo efficacy models;

[0736] Acceptable PK profile;

[0737] More traditional, well-established, and friendly administration modes (e.g., intravenous, subcutaneous, intramuscular, topical, etc.) can be used instead of intratumoral administration, to prolong the drug effect and reduce the side effects.

[0738] Specifically, the targeted inhibition of the ADC compound described in the present application can be that, compared with the addition of a negative control or a control drug, the proliferation ability of tumor cells with high expression of a specific target is reduced by more than 1%, more than 5%, more than 20%, more than 50%, or even more than 90% or 95% when the ADC compound is added to the culture medium of the tumor cells with high expression of the specific target. For example, the targeted inhibition can be that the IC50 value (nM) of the tumor cells with high expression of the specific target is 1000 or less, 500 or less, or 100 or less, for example, 1-500, 1-100; for example, the tumor cells can include but are not limited to solid tumor cells, such as breast adenocarcinoma cells, gastric cancer cells, lymphoma cells, ovarian adenocarcinoma cells, etc.; and the specific target includes but is not limited to HER2, TROP2, EGFR, and Claudin 18.2.

[0739] Specifically, the in vivo tumor inhibition effect of the ADC compound described in the present application can be that, compared with the addition of a negative control or a control drug, the volume of a tumor in an animal is reduced by more than 1%, more than 5%, more than 20%, more than 50%, or even more than 90% or 95% at 1, 3, 5, 7, 14, 21, or 30 days after administration to the animal. For example, compared with the administration of a negative control and a control drug, the volume of the tumor in the animal is reduced by more than 1.1 times, more than 1.5 times, more than 2 times, more than 5 times, more than 10 times, or even more than 100 times or 500 times at 1, 3, 5, 7, 14, 21, or 30 days. The animal includes but is not limited to a mammal. The administration includes but is not limited to oral administration, intravenous injection or infusion, intraperitoneal injection, or local administration.

[0740] Specifically, the distribution of the ADC compound described in the present application in a tumor tissue of an animal after administration can be increased by more than 1%, more than 5%, more than 20%, more than 50%, or even more than 90% or 95% compared with the distribution in other tissues and organs, or compared with the distribution of a CDN. For example, the distribution can be increased by more than 1.1 times, more than 1.5 times, more than 2 times, more than 5 times, more than 10 times, or even more than 100 times or 500 times. The animal includes but is not limited to a mammal, and the tissue or organ includes but is not limited to heart, liver, spleen, lung, kidney, brain, etc. The administration includes but is not limited to oral administration, intravenous injection or infusion, intraperitoneal injection, or local administration.

[0741] In particular, the ADC compounds described herein have good in vivo safety, in that the rate of release of free toxin in vivo after administration to an animal is no more than 50%, no more than 20%, no more than 10%, even no more than 1%, no more than 0.1%. For example, the in vivo safety is such that the compound can be administered at a concentration of 0.5 mg / kg or more, 5 mg / kg or more, 10 mg / kg or more, 50 mg / kg or more, 100 mg / kg or more, or even 500 mg / kg or more, without the animal exhibiting toxic effects. The animal includes, but is not limited to, a mammal. The administration includes, but is not limited to, oral, intravenous injection or infusion, intraperitoneal injection, or topical administration.

[0742] In particular, the ADC compounds described herein have good in vivo safety, in that the rate of release of free toxin in vivo after administration to an animal is no more than 50%, no more than 20%, no more than 10%, even no more than 1%, no more than 0.1%. For example, the in vivo safety is such that the compound can be administered at a concentration of 0.5 mg / kg or more, 5 mg / kg or more, 10 mg / kg or more, 50 mg / kg or more, 100 mg / kg or more, or even 500 mg / kg or more, without the animal exhibiting toxic effects. The animal includes, but is not limited to, a mammal. The administration includes, but is not limited to, oral, intravenous injection or infusion, intraperitoneal injection, or topical administration.

[0743] III. Pharmaceutical Compositions

[0744] Another aspect of the present disclosure provides pharmaceutical compositions comprising an ADC of the present disclosure and one or more pharmaceutically acceptable excipients, which can include components conventionally found in pharmaceutical preparations, such as diluents, carriers, pH adjusting agents, preservatives, solubilizers, stabilizers, wetting agents, emulsifiers, sweeteners, colorants, flavoring agents, salts to adjust osmotic pressure, buffers, masking agents, antioxidants, and other active agents. Suitable carriers and excipients are well known to those skilled in the art and are described in detail in, for example, Gennaro A.R. et al., Remington: The Science and Practice of Pharmacy (2000) Lippincott, Williams & Wilkins, Philadelphia.

[0745] The present disclosure also provides methods of using the ADCs of the present disclosure to prepare such compositions, which are typically prepared by mixing a compound of the present disclosure with a carrier or excipient, and can be formulated using a mode well known to those skilled in the art, consistent with good medical practice, such as described in, for example, Gennaro A.R. et al., Remington: The Science and Practice of Pharmacy (2000) Lippincott, Williams & Wilkins, Philadelphia or the Pharmacopeia of various countries.

[0746] The pharmaceutical compositions of the present disclosure can be in any suitable form, such as tablets, powders, capsules, sterile injectable preparations, solutions, dispersions, suspensions, syrups, sprays, suppositories, gels, emulsions, patches, and the like, and can be administered to a patient by a variety of routes, such as intravenously, intratumorally, subcutaneously, intramuscularly, orally, intranasally, intrathecally, transdermally, or topically. The route of administration in any given case can depend on the particular antibody and / or ADC, the subject, the nature and severity of the disease, and the physical condition of the subject. In certain embodiments, the pharmaceutical compositions will be administered intravenously, intratumorally, subcutaneously, or intramuscularly in the form of a liquid preparation.

[0747] In preferred embodiments, the ADCs described herein, as well as pharmaceutical compositions comprising them, are administered systemically, such as subcutaneously, intraperitoneally, intramuscularly, intravenously, particularly intravenously, especially in the form of a sterile injectable preparation, such as a sterile injectable solution or suspension in a non-toxic parenterally acceptable diluent or solvent, or in a form suitable for preparation of a lyophilized powder, for reconstitution with a suitable diluent or solvent prior to use; in acceptable vehicles or solvents, for example, water, 1,3-butanediol, Ringer's solution, or isotonic sodium chloride solution; and additionally, sterile, fixed oils can conventionally be employed as a solvent or suspending medium, for example, for long-term absorption, any bland fixed oil can be employed, including synthetic mono- or diglycerides, fatty acids and the like. In other embodiments, the ADCs described herein, as well as pharmaceutical compositions comprising them, are administered locally at the site of a tumor, such as intratumorally or in the tumor microenvironment.

[0748] The dosage of the compounds of the present disclosure can vary within wide limits and, of course, can be adjusted by the clinician according to the individual requirements in each particular case. For prophylactic or therapeutic purposes, a suitable dose (when used alone or in combination with one or more other therapeutic agents) of the ADCs of the present disclosure will depend on the type of disease to be treated, the type of antibody, the severity and course of the disease, whether the antibody is administered for preventive or therapeutic purposes, previous therapy, the patient's clinical history and response to the antibody, and the discretion of the attending physician.

[0749] The pharmaceutical compositions or formulations of the present disclosure can also contain more than one other active ingredient required for the particular indication being treated, preferably those with complementary activities that do not adversely affect each other. For example, it is desirable to provide other therapeutic agents, including chemotherapeutic agents, angiogenesis inhibitors, cytokines, cytotoxic agents, other antibodies, small molecule drugs, or immunomodulatory agents (e.g., immune checkpoint inhibitors or agonists), and the like. The active ingredients are present in amounts that are effective for the purpose intended.

[0750] IV: Pharmaceutical Combinations and Kits

[0751] In some embodiments, this disclosure also provides pharmaceutical combinations or pharmaceutical combination products comprising the ADC of this disclosure or a pharmaceutically acceptable salt, ester, isomer, prodrug, solvate, or isotopic variant thereof, and one or more other therapeutic agents for the prevention or treatment of diseases, such as those related to or mediated by STING, more specifically for the treatment or prevention of inflammation, allergic or autoimmune diseases, infectious or proliferative diseases, especially tumors or viral infections; thereby, this disclosure also provides methods for treating or preventing diseases, such as those related to or mediated by STING, more specifically for inflammation, allergic or autoimmune diseases, infectious or proliferative diseases, especially tumors or viral infections, in subjects, the method comprising administering the pharmaceutical combination of this disclosure to a human or animal.

[0752] Another object of this disclosure is to provide a kit containing the drug combination of this disclosure, preferably in the form of drug dosage units. This allows the dosage units to be provided according to a dosing regimen or drug administration interval.

[0753] In one embodiment, the kit of this disclosure comprises, within the same package:

[0754] - A first container containing a pharmaceutical composition comprising the ADC of the present disclosure or a pharmaceutically acceptable salt, ester, isomer, prodrug, solvate or isotopic variant thereof;

[0755] - A second container containing a pharmaceutical composition comprising other therapeutic agents.

[0756] Based on factors such as the disease to be treated and individual conditions, those skilled in the art can determine the administration method and order of administration of the components of the combined product. The combined product of this disclosure can be used in the treatment methods of this disclosure. In some embodiments, this disclosure provides a combined product in which the other therapeutic agents are, for example, antibodies that effectively stimulate an immune response to further enhance, stimulate, or upregulate the immune response of the subject. In some embodiments, the combined product is used to prevent or treat diseases, such as those related to or mediated by STING, particularly tumors.

[0757] V. Uses and Methods

[0758] Given that the first payload CDN compound of the ADC disclosed herein can activate STING, induce the expression of type I interferon and pro-inflammatory cytokines such as IL-6, TNF-α and IFN-γ, and has cytotoxic activity, and that the second payload can be selected from a variety of therapeutic agents with mechanisms compatible with STING agonists, this disclosure also provides therapeutic uses and methods of the ADC disclosed herein.

[0759] In certain embodiments, the present disclosure provides the ADCs disclosed herein for use in therapy.

[0760] The ADCs provided by the present disclosure can be used alone or in combination with each other and / or in combination with other therapeutic agents. As shown in the examples below, the ADCs are capable of promoting an immune response when administered to a subject. For example, the ADCs provided by the present disclosure are capable of inducing interferon B (IFNB) in a human subject, in part due to their ability to agonize STING. The binding of the CDN in the ADC to the antibody or antigen binding fragment that binds to a tumor-associated antigen or an immune cell antigen targets its delivery to tumor-associated immune cells or the tumor microenvironment to trigger activation of STING and generate an immune response that kills tumor cells and produces anti-inflammatory, anti-viral effects while prolonging or enhancing the immune response; in turn, the CDN released from the ADC is further broken down to release the cytotoxic moiety in the structure that further inhibits the survival of tumor cells.

[0761] Thus, the ADCs of the present disclosure are capable of promoting an immune response and tumor cell killing that is more potent than the effects of the un-conjugated CDN or the antibody contained in the ADC. In other words, the present disclosure achieves a synergistic effect by conjugating the CDN produced to a specific immunotherapeutic antibody, which is further enhanced by the cytotoxic moiety released from the further breakdown of the CDN, resulting in a triple synergistic effect. Further, the ADCs of the present disclosure are capable of achieving a synergistic effect in biological activity of the first payload by introducing a second payload.

[0762] Thus, in one aspect, the present disclosure accordingly provides a method of inducing, stimulating, or assisting an immune response in an individual, comprising administering to the individual an ADC of the present disclosure or a pharmaceutically acceptable salt, ester, isomer, prodrug, solvate, or isotopic variant thereof, or a pharmaceutical composition comprising the same. In one embodiment, the ADC of the present disclosure or a pharmaceutically acceptable salt, ester, isomer, prodrug, solvate, or isotopic variant thereof, or a pharmaceutical composition comprising the same is administered to the individual as an immunotherapy to induce the production of an excess of a variety of cytokines in the body that are therapeutically useful in humans or animals, including Type I interferons and pro-inflammatory cytokines such as IL-6, TNF-a, and IFN-g, to modulate the immune system of the human or animal to achieve certain therapeutic benefits.

[0763] In another aspect, the present disclosure accordingly provides a method of treating or preventing a disease associated with or mediated by an immune response, in particular a disease associated with or mediated by STING, including an inflammatory, allergic, or autoimmune disease, an infectious disease, or a cancer, comprising administering to a subject in need thereof a therapeutically effective amount of an ADC of the present disclosure or a pharmaceutically acceptable salt, ester, isomer, prodrug, solvate, or isotopic variant thereof, or a pharmaceutical composition comprising the same.

[0764] In another aspect, the present disclosure provides the use of the ADC of the present disclosure or a pharmaceutically acceptable salt, ester, isomer, prodrug, solvate or isotopic variant thereof, or a pharmaceutical composition comprising the same, in the prevention or treatment of a disease, for example a disease associated with or mediated by STING, more particularly in the treatment or prevention of an inflammatory, allergic or autoimmune disease, an infectious disease or a hyperproliferative disease, especially a tumor or a viral infection.

[0765] In another aspect, the present disclosure provides the ADC of the present disclosure or a pharmaceutically acceptable salt, ester, isomer, prodrug, solvate or isotopic variant thereof, or a pharmaceutical composition comprising the same, for use as a therapeutic agent for the treatment or prevention of a disease, for example a disease associated with or mediated by STING, more particularly for use as a therapeutic agent for the treatment or prevention of an inflammatory, allergic or autoimmune disease, an infectious disease or a hyperproliferative disease, especially as an anti-tumor or anti-viral therapeutic agent, or as a vaccine adjuvant; particularly as a cytotoxic agent for the treatment or prevention of a hyperproliferative disease, especially a tumor, or as a cytotoxic agent for the treatment or prevention of a viral infection.

[0766] In preferred embodiments, the ADC of the present disclosure or a pharmaceutically acceptable salt, ester, isomer, prodrug, solvate or isotopic variant thereof, or a pharmaceutical composition comprising the same, is used as a cytotoxic agent for the treatment or prevention of a hyperproliferative disease, especially a tumor. In further preferred embodiments, the ADC of the present disclosure or a pharmaceutically acceptable salt or solvate thereof, or a pharmaceutical composition comprising the same, is used for the treatment of a recurrent tumor, or for the prevention of tumor recurrence.

[0767] In another aspect, the present disclosure provides the ADC of the present disclosure or a pharmaceutically acceptable salt, ester, isomer, prodrug, solvate or isotopic variant thereof, or a pharmaceutical composition comprising the same, for use as a multifunctional active agent, which combines immunotherapeutic and cytotoxic therapeutic activities, including the ability to activate the immune system to exert anti-tumor and anti-viral replication functions by agonizing the STING signaling pathway, to cause tumor cell death or prevent viral replication by releasing a cytotoxic agent, to then sustain activation of STING by releasing tumor DNA to kill tumor cells, and to provide “immunological memory” or durable immunity to the tumor by releasing tumor neoantigens to generate an antibody-antigen response. In this regard, the present disclosure also provides the ADC of the present disclosure or a pharmaceutically acceptable salt or solvate thereof, or a pharmaceutical composition comprising the same, for use in achieving the above multifunctional activities, and the use thereof in achieving the above multifunctional activities.

[0768] In another aspect, the present disclosure provides a method of treating or preventing a disease, e.g., a disease associated with or mediated by STING, more specifically an inflammatory, allergic or autoimmune disease, an infectious disease or a hyperproliferative disease, especially a tumor or a viral infection, in a subject, the method comprising administering to the human or animal an ADC of the present disclosure or a pharmaceutically acceptable salt, ester, isomer, prodrug, solvate or isotopic variant thereof, or a pharmaceutical composition comprising the same; in particular, the present disclosure provides a method of treating or preventing a hyperproliferative disease, especially a tumor, or a method of treating or preventing a viral infection, in a subject, the method comprising administering to the human or animal an ADC of the present disclosure or a pharmaceutically acceptable salt, ester, isomer, prodrug, solvate or isotopic variant thereof, or a pharmaceutical composition comprising the same.

[0769] In another aspect, the present disclosure provides the use of an ADC of the present disclosure or a pharmaceutically acceptable salt, ester, isomer, prodrug, solvate or isotopic variant thereof, or a pharmaceutical composition comprising the same, in the manufacture of a medicament for preventing or treating a disease, e.g., a disease associated with or mediated by STING, more specifically an inflammatory, allergic or autoimmune disease, an infectious disease or a hyperproliferative disease, especially a tumor or a viral infection, or in the manufacture of a vaccine adjuvant; in particular, the present disclosure provides the use of an ADC of the present disclosure or a pharmaceutically acceptable salt or solvate thereof, or a pharmaceutical composition comprising the same, in the manufacture of a medicament for treating or preventing a hyperproliferative disease, especially a tumor, and the use of an ADC of the present disclosure or a pharmaceutically acceptable salt, ester, isomer, prodrug, solvate or isotopic variant thereof, or a pharmaceutical composition comprising the same, in the manufacture of a medicament for treating or preventing a viral infection.

[0770] The hyperproliferative disease for which the above uses and methods are directed is a physiological condition characterized by uncontrolled or deregulated cell growth or death in a subject, and in particular refers to a tumor or cancer, including solid tumors and blood-borne tumors, including but not limited to brain cancer, skin cancer, bladder cancer, ovarian cancer, breast cancer, stomach cancer, pancreatic cancer, prostate cancer, colon cancer, blood cancer, lung cancer (small cell lung cancer, non-small cell lung cancer), and bone cancer. Examples of the above cancer types include neuroblastoma, intestinal cancer such as rectal cancer, colon cancer, colorectal cancer, familial adenomatous polyposis cancer, and hereditary non-lymphomatous colorectal cancer, esophageal cancer, lip cancer, laryngeal cancer, nasopharyngeal cancer, pharyngeal squamous cancer, oral cavity cancer, head and neck cancer, salivary gland cancer, peritoneal cancer, soft tissue sarcoma, urothelial cancer, sweat gland carcinoma, gastric cancer, adenocarcinoma, medullary thyroid carcinoma, papillary thyroid carcinoma, renal cancer, renal parenchymal carcinoma, ovarian cancer, cervical cancer, uterine body cancer, endometrial cancer, pancreatic cancer, prostate cancer, testicular cancer, breast cancer (including HER2-negative breast cancer), urological cancer, melanoma, brain tumors such as glioblastoma, astrocytoma, meningioma, medulloblastoma, and peripheral neuroectodermal tumor, lymphoma such as Hodgkin's lymphoma, non-Hodgkin's lymphoma, Burkitt's lymphoma, acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL), chronic myelogenous leukemia (CLL), and lymphocytic cancer, acute myelogenous leukemia (AML), myelogenous leukemia (chronic myelogenous leukemia (CML), adult T-cell lymphoma, diffuse lymphoma (DLBCL), liver cancer, hepatocellular carcinoma, multiple myeloma, seminoma, osteosarcoma, chondrosarcoma, anal canal cancer, renal cell carcinoma, adrenal cortex cancer, chordoma, fallopian tube cancer, gastrointestinal stromal tumor, myeloproliferative disorder, mesothelioma, biliary tract cancer, Ewing's sarcoma, and other rare tumor types, and recurrent forms of the above tumors.

[0771] In preferred embodiments, the hyperproliferative disease for which the above uses and methods are directed is small cell lung cancer, non-small cell lung cancer, colorectal cancer, liver cancer, breast cancer, ovarian cancer, stomach cancer, prostate cancer, melanoma, renal cell carcinoma, head and neck cancer, pancreatic cancer, soft tissue sarcoma, Hodgkin's lymphoma, leukemia, or bladder cancer.

[0772] The viral infection against which the uses and methods described above are directed refers to the process by which a virus invades the body through various routes and proliferates in susceptible host cells, the viruses involved include but are not limited to double-stranded DNA viruses and single-stranded DNA viruses, single positive-strand RNA viruses, single negative-strand RNA viruses and double-stranded RNA viruses and retroviruses, examples are hepatitis B virus, TTV virus, adenovirus, papillomavirus, herpes zoster virus, smallpox virus and vaccinia virus, influenza virus, swine fever virus, hepatitis A virus, hepatitis C virus, hepatitis D virus, hepatitis E virus, hepatitis G virus, rabies virus, Ebola virus, enterovirus and human immunodeficiency virus, etc. The therapeutic uses and methods provided by the present disclosure can be used for the above viral infections and diseases caused thereby.

[0773] The uses of the ADCs of the present disclosure or pharmaceutically acceptable salts or solvates thereof or pharmaceutical compositions comprising the same as vaccine adjuvants and in the manufacture of vaccine adjuvants refer to the use of the ADCs of the present disclosure or pharmaceutically acceptable salts or solvates thereof or pharmaceutical compositions comprising the same as adjuvants in therapeutic or prophylactic strategies employing vaccines, i.e. the use of the ADCs of the present disclosure or pharmaceutically acceptable salts or solvates thereof or pharmaceutical compositions comprising the same together with one or more vaccines selected for stimulating an immune response to one or more predetermined antigens, the vaccines comprising inactivated or attenuated bacteria or viruses, for example inactivated tumor cells comprising expression and secretion of one or more of GM-CSF, CCL-20, CCL3, IL-12p70, FLT-3 ligand, cytokines.

[0774] Preparation of the ADCs of the present disclosure

[0775] 1. General synthetic methods

[0776] The compounds of the present disclosure, stereoisomers, tautomers, stable isotopic variants, pharmaceutically acceptable salts, or solvates thereof, can be prepared by a variety of methods well known in the art of organic synthesis, including the methods given below, the methods given in the examples, or methods analogous thereto, as appreciated by a skilled artisan.

[0777] The following illustrates general synthetic schemes for synthesizing the compounds of the disclosure. Appropriate reaction conditions for each of the reaction steps are known to those skilled in the art or can be routinely determined. In particular, the process steps for synthesizing the compounds of the disclosure can be carried out under reaction conditions known per se, including those specifically mentioned, in the absence or typically in the presence of a solvent or diluent, including, for example, solvents or diluents that are inert to the reagents used and that dissolve the reagents used, in the absence or in the presence of catalysts, condensing agents or neutralizing agents, for example ion exchangers, such as cation exchangers, for example in the H+form, at reduced, normal or elevated temperatures, for example from about -100°C to about 190°C, including, for example, from about -78°C to about 150°C, for example from about 0°C to about 125°C, room temperature, -20°C to 40°C or reflux temperature, under atmospheric pressure or in a closed vessel, if appropriate under pressure, and / or under an inert gas atmosphere, for example oxygen or nitrogen.

[0778] The starting materials and reagents used in preparing these compounds are generally available from commercial suppliers or can be prepared by methods analogous to those described herein, by methods described in the literature, or by methods known to those skilled in the art. If desired, the starting materials and intermediates in the synthetic reaction sequences can be isolated and purified by conventional techniques, including but not limited to filtration, distillation, crystallization, chromatography, and the like. The materials can be characterized using conventional methods, including physical constants and spectral data.

[0779] Unless otherwise indicated in the description of a process, solvents suitable for use in any particular reaction include: those specifically mentioned, or, for example, water; esters, such as lower alky! lower alkyl esters, for example, ethyl acetate; ethers, such as aliphatic ethers, for example diethyl ether, or cyclic ethers, for example tetrahydrofuran or dioxane; liquid aromatic hydrocarbons, such as benzene or toluene; alcohols, such as methanol, ethanol or 1- or 2-propanol, such as acetonitrile; halogenated hydrocarbons, such as dichloromethane or chloroform; amides, such as N,N-dimethylformamide or N,N-dimethylacetamide; bases, such as heterocyclic nitrogen bases, for example pyridine; carboxylic acid anhydrides, such as lower aliphatic carboxylic acid anhydrides, for example acetic anhydride; cyclic, linear or branched hydrocarbons, such as cyclohexane, hexane or isopentane; or mixtures of these solvents, for example aqueous solutions. Such solvent mixtures can also be used for work-up, for example by chromatography or partitioning.

[0780] One skilled in the art will recognize that stereocenters exist in the compounds of Formula I. At all stages of the reaction, mixtures of isomers formed can be separated into individual isomers, e.g., diastereomers or enantiomers, or into any desired mixture of isomers, e.g., racemates or mixtures of diastereomers, see, e.g., E. L. Eliel, S. H. Wilen, and L. N. Mander, "Stereochemistry of Organic Compounds" (Wiley-Interscience, 1994).

[0781] 2. First Payload - bifunctional cyclic dinucleotide CDN STING agonist fragment

[0782] The first payload in the dual payload antibody conjugate drug of the present disclosure is the bifunctional CDN STING agonist disclosed in patents WO2024153127 and WO2022083584, the synthesis and characterization of which are described in detail in the documents, and the documents are incorporated by reference in their entirety into the present disclosure.

[0783] In particular, the first payload in the dual payload antibody conjugate drug of the present disclosure is selected from the following compounds or their pharmaceutically acceptable salts or solvates, which are prepared and characterized according to the corresponding examples of patents WO2024153127 and WO2022083584, respectively:

[0784] 3. Second Payload

[0785] The second payload in the dual payload antibody conjugate drug of the present disclosure is a pharmaceutical compound generally or specifically described in the detailed description of the invention herein or its pharmaceutically acceptable salt or solvate. These compounds can be prepared based on the corresponding patent document (CN115990269) or are commercially available.

[0786] In particular embodiments, the second payload in the dual payload antibody conjugate drug of the present disclosure can be selected from the following commercially available drugs or their pharmaceutically acceptable salts or solvates.

[0787] 4. Synthesis of key intermediate PL

[0788] As described above, the dual payload (bifunctional cyclic dinucleotide payload 1 and payload 2) of the ADC of the present disclosure is associated with the antibody via the key intermediate PL, as shown in Figure 6.

[0789] The following Scheme 1 illustrates the general formula of the key intermediate PL that can be used to prepare the dual payload conjugate drug of the present disclosure, each variable has the same meaning as defined herein or in each specific embodiment of the compound or its respective, unless otherwise stated.

[0790] Scheme 1

[0791] The amino group in intermediate B is reacted with an active ester bearing a succinamide group to produce intermediate C,

[0792] The free carboxyl group in C is reacted with the free amino group in intermediate A in the presence of a condensing agent (such as DMTMM) to produce the key intermediate PL.

[0793] Scheme 2 illustrates a general method for the preparation of intermediate A.

[0794] Scheme 2

[0795] Commercially available intermediate D, where AA1, AA2, AA3and AA4represent amino acids as defined for the "cleavable linker" section of the detailed description of the invention, is converted to the benzyl halide, most preferably benzyl iodide E, using a halogenating reagent (such as dichlorosulfur dioxide, etc.).

[0796] The iodine in intermediate E reacts directly with one of the -SH groups in the CDN molecule in a suitable solvent (such as DMF) to produce intermediate F,

[0797] Intermediate F is deprotected from the Fmoc group in the presence of an organic base (such as diethylamine) to produce intermediate A. Other amino protecting groups (such as Cbz, etc.) can be used and the corresponding deprotection method is used at this step to produce the free amine intermediate A.

[0798] Scheme 3 illustrates a general method for the preparation of intermediate B.

[0799] Scheme 3

[0800] Commercially available intermediate D, where AA5, AA6, AA7and AA8represent amino acids as defined for the "cleavable linker" section of the detailed description of the invention, is treated with di-p-nitrocarbonate to produce the active carbonate G,

[0801] The free amine group or hydroxyl group in the payload 2 reacts with G to produce intermediate H,

[0802] The allyl ester in intermediate H can be hydrolyzed in the presence of triphenylphosphine palladium to produce the free acid intermediate I; if the starting material D is a methyl ester, I can be produced by hydrolysis using an inorganic base (such as LiOH).

[0803] Intermediate I is deprotected from the Fmoc group by the action of an organic base such as diethylamine to give Intermediate B. Other amino protecting groups such as Cbz and the like can also be used and the corresponding deprotection methods are used at this step to remove the free amine Intermediate B.

[0804] Intermediate H can also be prepared by the method of Scheme 4 with the details as described in Scheme 2 and not repeated.

[0805] Scheme 4

[0806] When the attachment point of the Payload 2 is O, Intermediate B can be prepared by Scheme 5 via Intermediates J and K similar to Scheme 2 with the details as described in Scheme 2 and Scheme 3 and not repeated.

[0807] Scheme 5

[0808] Active ester leaving groups in the schemes can also be pentafluorophenol and the like; some Payload fragments require functional group protection-deprotection manipulations compatible with the reaction conditions in the schemes; as embodied in the Examples, a variety of solubilizing groups can be introduced into the molecular structures of the schemes by common organic synthesis methods and following the procedures of the schemes.

[0809] 5. Selection and Synthesis of Antibodies

[0810] Antibodies used in the ADCs of the disclosure are derived from commercial sources, including but not limited to antibodies to the following targets: KIT, FOLR1, CD276, PD-L1, NECTIN4, Mesothelin, MUC1, GCPII, BCMA, cMet, RPR1, CD22, CD19, TOP1, Claudin 18.2, EGFR, Trop-2, HER2, and the like, and bispecific antibodies thereto.

[0811] 6. Synthesis of Dual Payload CDN-Linker-Antibody Conjugate ADCs

[0812] Generation of antibody-drug conjugates can be accomplished by any technique known to those skilled in the art. In some aspects, conjugation of the drug-linker to the antibody is accomplished by reaction with an amino acid residue of the antibody. In some embodiments, a linker L bearing a leaving group is used to conjugate a drug D to a cysteine residue of an antibody to make a conjugate of Formula A of the disclosure. In some embodiments, the interchain disulfide bonds of the antibody can be broken and free thiols exposed for conjugation to the linker-drug by controlling the conditions under which the antibody is treated with a reducing agent, such as tris(2-carboxyethyl)phosphine (TCEP). For IgGl type antibodies, up to four interchain disulfide bonds can be reduced, resulting in up to 8 reactive thiol groups for conjugation. Conjugates made by this method can have zero, one, two, three, four, five, six, seven, or eight drug molecules conjugated per antibody molecule.

[0813] In preparing a conjugate that is a composition of conjugates having different drug conjugation sites and / or numbers, the drug loading of the conjugate is represented by the average DAR, and the average DAR of the antibody-drug conjugate composition produced by the preparation can be characterized by conventional means such as mass spectrometry, ELISA assays, and HPLC, and the quantitative distribution of antibody-drug conjugates in terms of q can also be determined. The separation, purification, and characterization of homogenous antibody-drug conjugates having a certain value of q from antibody-drug conjugates having other drug loadings can be achieved by means such as reverse phase HPLC or electrophoresis.

[0814] Scheme 6 below illustrates a general synthetic route that can be used to prepare the dual payload CDN compounds described herein and each of their specific embodiments. Each variable of the general formula in the following scheme has the same meaning as defined for the compounds described herein or each of their specific embodiments, unless otherwise stated.

[0815] Scheme 6

[0816] The antibody molecule is first reduced, preferably the disulfide bonds of the antibody molecule are reduced. The heavy chain and light chain of the antibody molecule are connected to each other by 4 pairs of disulfide bonds. These disulfide bonds can be reduced to a maximum of 0-8 thiols with a reducing agent (such as tris(2-carboxyethyl)phosphine TCEP, mercaptoethanol, dithiothreitol, cysteine, reduced glutathione, etc.), each of which can react with succinamide to generate 0-8 bifunctional CDN-linker derivatized antibody conjugates ADC. The average drug loading DAR (drug / antibody ratio) of the compound can be determined experimentally.

[0817] Experimental materials and reagents used in the above synthetic methods and schemes, unless otherwise specified, are available from commercial sources, prepared according to methods known in the art, or prepared according to methods analogous to those disclosed herein. Synthetic conditions used in the above synthetic methods and schemes, unless otherwise specified, can be routinely determined by one skilled in the art.

[0818] The present disclosure also relates to methods of preparation in which a compound obtainable as an intermediate in any of the preparation methods and schemes described herein is used as a starting material and the remaining method steps are carried out, or in which the starting material is formed in situ under the conditions of the reaction or is used in the form of a derivative, for example in the form of a protected derivative or salt, or in which a compound obtainable according to the methods of the present disclosure is formed under the conditions of the method and is further processed in situ. 7. DETAILED DESCRIPTION

[0819] The present disclosure is further illustrated by the following examples. It is to be understood that the examples below do not limit the scope of the present disclosure.

[0820] Unless the context clearly indicates otherwise, the chemical names of any compound of the present disclosure are to be taken as being consistent with the structure given.

[0821] The experimental methods used in the following examples, unless otherwise indicated, were generally in accordance with conventional methods of such reactions, or as suggested by the manufacturer. Experimental materials and reagents used in the following examples, unless otherwise specified, are available from commercial sources, prepared according to methods known in the art, or prepared according to methods analogous to those disclosed herein.

[0822] Unless otherwise indicated, percentages and parts are percent by weight and parts by weight; ratios of liquids are by volume; and all temperatures are given in degrees Celsius, unless otherwise indicated.

[0823] In the following examples, 1 H NMR spectra 31P NMR spectra were recorded on a Bruker 400 MHz NMR and 500 MHz NMR spectrometer, chemical shifts are expressed in δ (ppm); mass spectra were recorded on an Agilent 1290 liquid chromatography + 6120B mass spectrometry LCMS; silica gel column purification was performed on a Biotage Selekt SEL-2SV or ISO-1SV; preparative liquid chromatography purification was performed on a Gilson 281 (column: waters Xbridge 19 mm x 250 mm x 5 μm or WELCH C18, 21.2 mm x 250 mm x 10 μm. Mobile phase: A: water (10 mM NH4HCO3 or 0.05% formic acid), B: acetonitrile (or containing 0.05% formic acid). Flow rate: 20-30 mL / min. Detection wavelength: 214 nm / 254 nm), or as otherwise indicated.

[0824] The following abbreviations are used in the synthetic examples below, each of which has the meaning commonly understood by one of skill in the art.

[0825] A (absorbance); AA (amino acid); ACN or CH3CN or MeCN (acetonitrile); ADC (antibody-drug conjugate); Boc (tert-butyloxycarbonyl); (Boc)20 (di-tert-butyl dicarbonate); BOP (benzotriazol-1- yloxytris(dimethylamino)phosphonium hexafluorophosphate); t-Bu (tert-butyl); t-BuOK (sodium tert-butoxide); CBr4 (carbon tetrabromide); Cbz (benzyloxycarbonyl); CDCl3 (deuterated chloroform); CDN (cyclic dinucleotide); CD3OD-d4 (tetra-deuterated methanol); cm (centimeter); cm 2 CsCO3 (cesium carbonate); DAR (drug-antibody ratio); DCM (dichloromethane); DIEA or DIPEA (N,N-diisopropylethylamine); DMF (N,N-dimethylformamide); DMSO (dimethyl sulfoxide); DMSO-d6 (hexadeuterodimethyl sulfoxide); DMTMM (4-(4,6-dimethoxytriazin-2-yl)-4-methylmorpholinium chloride); D2O (deuterium oxide); DTT (dithiothreitol); E (trans-alkene); EA (ethyl acetate); ED50 (50% effective dose); ELISA (enzyme-linked immunosorbent assay); eq (equivalents); Et2NH (diethylamine); 19 F (fluorine nucleus); FCC (flash column chromatography); Fmoc (9-fluorenylmethoxycarbonyl); g (gram); h (hour); 1H (proton); H2(hydrogen gas); HATU (tetramethyluronium hexafluorophosphate); HC1 (hydrogen chloride); HF (hydrogen fluoride); HFIP (hexafluoroisopropanol); HMDSLi (lithium bis(trimethylsilyl)amide); H2O (water); HOBt (1-hydroxybenzotriazole); HPLC (high performance liquid chromatography); Hz (hertz); I (optical path length); I2(iodine); IC50(50% inhibition concentration); IFNβ (interferon beta); in vitro (in vitro experiment); in vivo (in vivo experiment); IV or i.v. (intravenous administration); J (nuclear magnetic resonance coupling constant); KI (potassium iodide); L (liter); L (relative stereochemical configuration); LCMS (liquid chromatography-mass spectrometry); LC-MS / MS (liquid chromatography-mass spectrometry-mass spectrometry); LiOH (lithium hydroxide); M or MW (molecular weight); M (molar concentration); NaI (sodium iodide); MeOH (methanol); MeONa (sodium methoxide); mg (milligram); MHz (megahertz); min (minute); mL (milliliter); mm (millimeter); mm 3 (3 millimeter); mM (millimolar concentration); mmol (millimole); MS (mass spectrometry); MS-ESI (electrospray ionization mass spectrometry); MW (microwave); m / z (mass-to-charge ratio); N2(nitrogen gas); NaCl (sodium chloride, common salt); Na2CO3(sodium carbonate); NaOAc (sodium acetate); Na2SO4(sodium sulfate); NCS (chloro succinimide); NH3(ammonia); NH4Cl (ammonium chloride); NH4HCO3(ammonium bicarbonate); nm (nanometer); NMR (nuclear magnetic resonance); 31 P (phosphorus nucleus); PABC (p-aminobenzoic acid); Pb(OAc)4(tetraacetate lead); PBS (phosphate buffered saline); Pd / C (palladium on carbon); Pd(OAc) (palladium acetate); Pd(OH)2(palladium hydroxide); Pd(PPh3)4(tetrakis(triphenylphosphine)palladium); PE (petroleum ether); PPh3(triphenylphosphine); PO or P.O. or p.o. (peroral administration); psi (pound force / square inch); Py (pyridine); R (R configuration of a chiral molecule); RP-HPLC (reverse phase high performance liquid chromatography); r.t. (room temperature); R t(S chromatographic retention time); S (S configuration of a chiral molecule); s / d / t / q / m (single / double / triple / quadruple / multiple split peaks in NMR); SFC (supercritical fluid chromatography); Si02(silica gel); SO2Cl (sulfonyl chloride); TCEP (tris(2-carboxyethyl)phosphine); TEA or Et3N (triethylamine); TBSCl (dimethyl-tert-butylsilyl chloride); TFA (trifluoroacetic acid); TGI (tumor growth inhibition rate); THF (tetrahydrofuran); TLC (thin layer chromatography); TMSI (trimethylsilyl iodide); TsOH (p-toluenesulfonic acid); TsOH-H2O (p-toluenesulfonic acid monohydrate); v / v (volume ratio); w / w (weight ratio); Z (cis olefin); δ (chemical shift); μL (microliter); μm (micrometer); μM (micromolar concentration); μmol (micromole).

[0826] Preparation of payload-linker intermediate PL

[0827] 1) Preparation of linker intermediate Pep

[0828] Preparation of Pep-1

[0829] Step A: To a solution of Fmoc-L-citrulline (5.0 g, 12.58 mmol) in anhydrous DMF (200 mL) at 0 °C, HATU (5.7 g, 15.09 mmol) and 4-(hydroxymethyl)aniline (1.85 g, 15.09 mmol) were added successively, followed by dropwise addition of DIEA (2.4 g, 18.87 mmol), and the resulting mixture was stirred at 0 °C to room temperature for 2 hours. After the reaction was completed, the resulting mixture was poured into ice water (1000 mL), the mixture was stirred at room temperature for 10 minutes, filtered, the filter cake was collected and dried under vacuum to give compound Pep-1-2 (5.8 g, yield 92.1%) as a yellow solid. MS-ESI [M+H] + : 503.2.

[0830] Step B: To a solution of compound Pep-1-2 (2.5 g, 4.97 mmol) in tetrahydrofuran (20 mL) at 0 °C, diethylamine (20 mL) was added, and the mixture was stirred at room temperature for 2 hours. After the reaction was completed, the solvent was removed by concentration, and a mixture of methyl tert-butyl ether and tetrahydrofuran (300 mL:10 mL) was added, and the mixture was stirred for 10 minutes, filtered, the filter cake was collected and dried under vacuum to give compound Pep-1-3 (1.0 g, yield 71.9%) as a yellow solid. MS-ESI [M+H] + : 281.2.

[0831] Step C: To a solution of N-Fluorenylmethoxycarbonyl-L-glutamic acid 5-allyl ester (compound Pep-1-4, CAS No. 133464-46-7, purchased from Shanghai Biotech Pharmaceutical) (10 g, 24.42 mmol) in dry DMF (200 mL) at 0 °C, HATU (11.1 g, 29.3 mmol) and L-valine tert-butyl ester hydrochloride (5.1 g, 24.42 mmol) were added successively, followed by slow dropwise addition of DIEA (6.3 g, 48.84 mmol), the resulting mixture was stirred at 0 °C to room temperature for 1 hour. After the reaction was completed, the reaction liquid was poured into ice water (1000 mL), stirred at room temperature for 30 minutes, filtered, the filter cake was collected and dried under vacuum to obtain a solid, which was poured into methyl tert-butyl ether (500 mL), stirred at room temperature for 10 minutes, filtered, the filter cake was collected and dried under vacuum to obtain yellow solid compound Pep-1-5 (13.4 g, yield 97.2 %). MS-ESI [M+Na] + : 587.3.

[0832] Step D: Compound Pep-1-5 (13.4 g, 23.73 mmol) was added to 6M HCl / dioxane (250 mL) at 0 °C, the resulting mixture was stirred at room temperature for 4 hours. After the reaction was completed, ...

Claims

1. A dual payload antibody conjugate drug of formula (X-1), wherein Ab represents an antibody or antigen binding fragment; L represents a linker unit connecting D1 and D2 to Ab; D1 represents a first payload, which is a compound of formula (II): wherein B1 is adenine optionally substituted with X wherein X is selected from H, Cl, F or -NHC 1-6 alkyl; or optionally substituted by wherein R b selected from H or -C 1-6 alkyl, R1and R1are each independently selected from H, F or -OH, B2 is guanine wherein R b selected from H or -C 1-6 alkyl, represents a phosphodiester bond which is connectable to the 2' or 3' position of a pentose, the position not forming a ring with the phosphodiester with R2and R2substituted, and R2and R2are each independently selected from H, -OH or F, D2represents a second payload; q represents a bond to Ab the number of which is an integer or non-integer from about 1 to 20; wherein D1 is connected to L via an amino group on any one of the -SH, B1or B2bases or an -OH on the sugar ring, preferably via any one of the -SH; or a pharmaceutically acceptable salt, ester, isomer, solvate, prodrug or isotopically-labeled version thereof.

2. The dual load antibody conjugate drug according to claim 1, wherein B1 in formula (II) is adenine wherein X is selected from H, CI, F or -NHC 1-6 alkyl, or is guanine wherein R b is -C 1-6 alkyl, for example 3. The dual payload antibody conjugate drug of claim 1 or 2, wherein R1and R1in formula (II) are both H, or one is H and the other is F, or one is H and the other is OH.

4. The dual payload antibody conjugate drug of any one of claims 1 to 3, wherein B2 in formula (II) is guanine 5. The dual payload antibody conjugate drug of any one of claims 1 to 4, wherein R2and R2in formula (II) are one H and the other is OH.

6. The dual payload antibody conjugate drug of any one of claims 1 to 5, wherein formula (II) has the following formula: Specifically, the fragment of formula (II) is linked to L by:

7. The dual payload antibody conjugate drug of claim 6, wherein R1and R1are both H, or R1is H and R1is F, or R1is H and R1is OH.

8. The dual payload antibody conjugate drug of claim 6 or 7, wherein B1 is ###00010### and R1 is F and R1' is H; or B1 is ###00011### and R1 is OH and R1' is H; or B1 is ###00012### and R1 is F and R1' is H.

9. The dual payload antibody conjugate drug of any one of claims 6 to 8, wherein B2 is guanine 10. The dual payload antibody conjugate drug of any one of claims 6 to 9, wherein R2is H and R2is -OH.

11. The dual-loaded antibody-drug conjugate of claim 1, wherein the compound of formula II is selected from: or a pharmaceutically acceptable salt, ester, isomer, solvate, prodrug or isotopically-labeled version thereof.

12. The dual payload antibody conjugate drug according to any one of claims 1 to 11, wherein the second payload D2is any therapeutic agent compatible with the cGAS-STING pathway, preferably an antitumor agent, for example selected from a topoisomerase I inhibitor such as camptothecin or a derivative thereof, further preferably a cytotoxic agent, a PARP inhibitor, a nucleoside derivative, a folate antagonist, a microtubule inhibitor, a nuclear receptor modulator, an immunomodulator, an epigenetic modulator, a topoisomerase II inhibitor, a phosphatase inhibitor, a kinase inhibitor; or for example the second payload D2is selected from a topoisomerase I inhibitor such as camptothecin or a derivative thereof, a PARP inhibitor, a kinase inhibitor, a topoisomerase II inhibitor, a nucleoside derivative, a microtubule inhibitor, a nuclear receptor modulator; or For example the second payload D2 is selected from or a pharmaceutically acceptable salt, ester, isomer, solvate, prodrug or isotopically-labeled version thereof.

13. The dual payload antibody conjugate drug according to any one of claims 1 to 12, wherein formula (X-1) has the following formula: wherein Ab represents an antibody or antigen binding fragment; G represents an antibody linker connected to Ab; E represents an optional property modulating unit; W represents a branching linker; P1and P2are each independently a cleavable linker selected from a peptide residue of 2-8 amino acids, preferably a dipeptide, tripeptide or tetrapeptide; A1and A2are each independently an optional self-immolative linker; S1and S2are each independently an optional solubilizing unit; D1is as defined in any one of claims 1 to 11; D2is as defined in claim 12; q represents an integer or non-integer from 1 to 20; For example, Formula (I-1) when E is absent: For example, formula (I-2) when E and S1 are absent: For example, formula (I-3) when E, S1, S2 are all absent:

14. The dual payload antibody conjugate drug according to claim 13, wherein G has the following structure: -G1-G2-, wherein: G1is selected from: • 5-10 membered heterocyclyl, containing 1 or 2 heteroatoms selected from N, S and O, wherein the ring carbon atoms are optionally oxidized; and · wherein the left side * indicates the point of attachment to the antibody, and the right side represents the point of attachment to G2; G2is selected from -C 1-10 alkylene-C(=0)-, -C 1-10 alkylene-C(=0)-NH-C 1-10 alkylene-O-C 1-10 alkylene-C(=0)-, wherein G2is attached to the property adjustment unit E (when present) or branching unit W (when E is absent) through its -C(=0)-, the other end group being attached to G1, or G2is selected from -C 1-10 alkylene-NH-, wherein G2is attached via its -NH- to the property adjustment unit E (when present) or the branching unit W (when E is absent), the other end group being attached to G1; wherein -C in G2 is 1-10 alkylene - optionally substituted with a Bu group, said Bu group being of formula (G): wherein, T0is -C 1-6 alkylene-; T is selected from -C(R a )2- -O- -NR a - or is absent; M is selected from -CO-, -0-, -NR a - or is absent; Z is selected from a glycosyl group or a derivative thereof and comprises hydrophilic peptides, preferably selected from the group consisting of glucose, mannose, galactose or their respective uronic acids, amino sugars, acylated amino sugars, amino sugar uronic acids or acylated amino sugar uronic acid derivatives, and hydrophilic peptides R, R a each independently C 1-6 alkyl, preferably -CH3, the fragment indicated in square brackets is a polyarginine, polyalanine, polyglycine comprising 4-14 units or 4-10, 5-10 units, more preferably a polyalanine comprising 4-12, 6-12 units or 4-10, 5-10 units; R a selected from H or C 1-6 alkyl; subunit is selected from the group consisting of natural amino acid residues and non-natural amino acid residues; n is an integer from 0 to 4, such as 0-2, 1-2, 1-4, 2-4; m is an integer from 0 to 20, such as 1-20, 1-10, 2-10, 2-8, 2-6, 2-4, 4-14, 4-12, 4-10, 5-10, 6-10, 6-12, 8-10, 8-14, such as 4-14, 4-12, 6-12 or 4-10, 5-10.

15. The dual payload antibody conjugate drug according to claim 13 or 14, wherein G is selected from the group consisting of: for example, selected from the group consisting of 16. The dual-loaded antibody-drug conjugate according to any one of claims 13 to 15, wherein E, when present, is a polyethylene glycol chain composed of 2-12 ethylene oxide (CH2CH2O) subunits, via -NH-, -C(=O)-, -C 1-4 Alkylene, -C 1-4 Alkylene -C(=O)-, -NH-C(=O)-(CH2OCH2)-C(=O)-, -C 1-4 Alkylene -NH-C(=O)-(CH2) 1-4 -O-(CH2) 1-4 -C(=O)- or -C 1-4 Alkylene-NH-(CH2) 1-4 -O-(CH2) 1-4 -C(=O)- connects between G and W.

17. Dual payload antibody conjugate drug according to any one of claims 13 to 16, wherein W is an amino acid residue, preferably wherein the -NH terminal is attached to E or G and the -CO- terminal is attached to P1 and P2.

18. The dual-load antibody-drug conjugate according to any one of claims 13 to 17, wherein P1 or P2 is a cleavable peptide having the following structure from the N-terminus to the C-segment: -(AA) d - where each of AA is independently selected from alanine, glycine, asparagine, isoleucine, leucine, valine, phenylalanine, citrulline, and glutamic acid; preferably, AA is selected from alanine, glycine, asparagine, valine, phenylalanine, citrulline, and glutamic acid; d is an integer from 2 to 12, preferably an integer from 2 to 8, and more preferably an integer from 2 to 4. For example, P1or P2is selected from: wherein the bond indicated by the wavy line is attached to the branch unit W at the N-terminus.

19. The dual payload antibody conjugate drug according to any one of claims 13 to 18, wherein A1 or A2 is selected from wherein, the site marked with an * is the point of attachment to D1 or D2, and the bond indicated by the wavy line is attached to the cleavable linker P1 or P2; each occurrence of Y1is independently selected from NH or O; R is, at each occurrence, independently selected from the group consisting of H and -C(O)R 16 each R is independently selected from the group consisting of H and -C(O)R 1-6 alkyl, preferably H or C 1-3 alkyl, more preferably H or methyl; Each occurrence of R 17 Each is independently selected from H, -NO2, -NH2, and -CF3; For example, A1or A2is selected from For example, A1is selected from and A2is selected from For example, A1is selected from and A2is selected from 20. The dual payload antibody conjugate drug according to any one of claims 13 to 19, wherein the phenyl ring structure comprised in A1 and / or A2 is optionally substituted with a solubilizing unit S1 or S2 of formula (S): ###00012### (S) ​ wherein, T' is selected from -C(R a )2- -O-, -NR a - or is absent; M' is selected from -CO-, -0-, -NR a - or is absent; Z' is selected from the group consisting of a glycosyl group or a derivative thereof and comprises a hydrophilic peptide, wherein the glycosyl group or derivative thereof is preferably selected from glucose, mannose, galactose, lactose, maltose, sucrose or their respective uronic acid, amino sugar, acylated amino sugar, amino uronic acid or acylated amino uronic acid derivatives, more preferably glucose, mannose, galactose or their respective said derivatives, wherein the hydrophilic peptide is preferably more preferably wherein R can be R a ; preferably, wherein the moiety indicated by square brackets is a poly- sarcosine, a poly-arginine, a poly-glycine, preferably a poly-sarcosine; R a selected from H or C 1-6 alkyl, preferably H or -CH3, more preferably -CH3; subunit is selected from the group consisting of natural amino acid residues and non-natural amino acid residues; n’ is an integer from 0 to 4, such as 0-2, 1-4, 1-2, 2-4; m is an integer from 0 to 20, such as 1-20, 1-10, 2-10, 2-8, 2-6, 2-4, 4-14, 4-12, 4-10, 5-10, 6-10, 6-12, 8-10, 8-14, such as 4-14, 4-12, 6-12 or 4-10, 5-10.

21. The dual payload antibody conjugate drug according to any one of claims 13 to 20, wherein A1and A2are each independently selected from preferably S1or S2is attached to the phenyl ring of A1or A2and is wherein T' is selected from -C(R a )2-, -0-, -NR a - or is absent, M' is selected from -CO-, -0-, -NR a - or is absent, n is an integer from 0 to 4, R a is H or C 1-6 alkyl; Z’ is a monosaccharide or disaccharide group or a derivative thereof, such as selected from the group consisting of glucose, mannose, galactose, lactose, maltose, sucrose or their uronic acid, aminosugar, acylated aminosugar, aminosugar uronic acid or acylated aminosugar uronic acid derivatives, preferably a monosaccharide glucose, mannose, galactose or their respective indicated derivative; or Z' is wherein R is -C 1-6 alkyl, preferably -CH3, the moiety indicated in square brackets is in particular a polyarginine, polyglycine, polyornithine comprising 4 to 14 units or 4 to 10, 5 to 10 units, preferably a polyornithine comprising 4 to 12, 6 to 12 units or 4 to 10, 5 to 10 units.

22. The dual payload antibody conjugate drug according to any one of claims 1 to 21, wherein linker unit L is: wherein the bond indicated by the wavy line is attached to Ab and the asterisk indicates the point of attachment to D1 or D2.

23. The dual payload antibody conjugate drug of any one of claims 1 to 22, wherein Ab is an antibody or antigen-binding fragment thereof that binds to a tumor-specific antigen or a tumor-associated antigen, wherein the tumor-specific antigen or tumor-associated antigen is selected from the group consisting of: HER2, Her3, HER1 (ErbB1), HER4 (ErbB4), TROP2, Nectin4, Tissue Factor, PD-L1, PD-1, PD-L1 / PD-L2, MET, CLDN18.2, KIT, CTLA-4, RPR1, Epidermal Growth Factor A2 receptor (EphA2), Folate Receptor a (FRa), Mesothelin, Endothelin Receptor, GCPII, IL-13Ra, BCMA, GD2, CLL-1, CA-IX, MUC1, 5T4, AOC3, ALK, AXL, C242, CA-125, CCL11, CCR5, CD2, CD3, CD4, CDS, CD15, CA15-3, CD16, CD18, CD19, CD20, CD21, CD22, CD25, CD30, CD32, CD33, CD37, CD38, CD44, CD52, CD56, CD64, CD66e, CD70, CD72, CD74, CD79a, CD79b, CD123, CD138, CD142, CD174, CD276, CDH3, CDH6,CDH17, CCD79b, CLDN9 / CLDN6, CA19-9, DPEP3, AGS-16, IGF1R, IGF2R, VEGFR1, VEGFR2, VEGFR3, PDGFR-a, PDGFR-b, EGFR, EGFRvIII, ENPP3, FcRH5, FRa, KAAG1, LIV-1, Mesothelin, cMet, ROR1, SLTRK6, TF, BMPR1B, E16, TOP1, STEAP1, Steap2, 0772P, MUC16, Napi2b, Napi3b, Sema 5b, PSCA hlg, ETBR, RNF124, Prostate-cancer associated gene 1, TrpM4, Tumour derived growth factor 1, C3DR, FcRH2, NCA, MDP, IL20R-a, Brevican, EphB2R, ASLG659, Prostate stem cell antigen precursor, GEDA, BAFF-R, CXCR5, CCR2, CCR8, HLA-DOB, P2X5, LY64, FcRH1, IRTA2, TENB2, Integrin a5b6, Integrin a4b7, FGF2, FGFR1, FGFR2, FGFR3, FGFR4, PSMA, Somatostatin receptor, RANK, SLAMF7, ITGB6, CEACAM5, CA9, EGFRvlll, IL2RA, AXL receptor tyrosine kinase, TGF-bR, TNFRSF8, Cancer / testis associated antigen, CLEC14A, GRP78, Stem cell specific antigen, ASG-5, PRR4, GUCY2C, SLC39A6, TPBG, Mid-tumor associated antigen CA242, FOLR1, GPNMB, HAVCR1, Prostate tumor target Mindin, VTCN1, PTK7 protein tyrosine kinase 7, Macrophage stimulating 1 receptor, TACSTD2, CA6, DLL3, DLL4, EpCAM, FAP, Fibronectin-EDB, DKK-1, Endoglin, VCAM1, GPC3, DR5, ASCT2, B7H1, B7H3, B7H4; Preferably, the tumor specific antigen or tumor associated antigen is selected from the group consisting of AXL, B7H1, B7H3, B7H4, BCMA, CD16, CD19, CD22, CD25, CD30, CD32, CD33, CD44, CD64, CD70, CD74, CD79, CD138, CD142, CD276, CDH3, CEACAM5, Claudin 18.2, CLDN9 / CLDN6, DPEP3, EGFR, ENPP3, EphA, FcRH5, FOLR1, FRa, GCPII, HER2, HER3, KAAG1, KIT, LIV-1, Mesothelin, cMet, MUC1, NECTIN4, PD-L1, PD-L1 / PD-L2, PSMA, ROR1, RPR1, TF, TOP1, TROP2; More preferably, the tumor specific antigen or tumor associated antigen is selected from the group consisting of an antibody or antigen binding fragment thereof that specifically binds to HER2, Claudin 18.2, EGFR and / or TROP2.

24. The dual-load antibody-drug conjugate of any one of claims 1 to 23, wherein the Ab comprises three heavy chain complementarity-determining regions (HCDRs) and three light chain complementarity-determining regions (LCDRs), wherein: According to the Kabat definition, HCDR1 comprises or consists of the amino acid sequence of SEQ ID NO: 6, HCDR2 comprises or consists of the amino acid sequence of SEQ ID NO: 7, HCDR3 comprises or consists of the amino acid sequence of SEQ ID NO: 8, LCDR1 comprises or consists of the amino acid sequence of SEQ ID NO: 3, LCDR2 comprises or consists of the amino acid sequence of SEQ ID NO: 4, and LCDR3 comprises or consists of the amino acid sequence of SEQ ID NO: 5; or HCDR1 comprises or consists of the amino acid sequence of SEQ ID NO: 18, HCDR2 comprises or consists of the amino acid sequence of SEQ ID NO: 19, HCDR3 comprises or consists of the amino acid sequence of SEQ ID NO: 20, LCDR1 comprises or consists of the amino acid sequence of SEQ ID NO: 15, LCDR2 comprises or consists of the amino acid sequence of SEQ ID NO: 16, and LCDR3 comprises or consists of the amino acid sequence of SEQ ID NO: 17; or HCDR1 comprises or consists of the amino acid sequence of SEQ ID NO: 29, HCDR2 comprises or consists of the amino acid sequence of SEQ ID NO: 30, HCDR3 comprises or consists of the amino acid sequence of SEQ ID NO: 31, LCDR1 comprises or consists of the amino acid sequence of SEQ ID NO: 26, LCDR2 comprises or consists of the amino acid sequence of SEQ ID NO: 27, and LCDR3 comprises or consists of the amino acid sequence of SEQ ID NO: 28; or HCDR1 comprises or consists of the amino acid sequence of SEQ ID NO: 40, HCDR2 comprises or consists of the amino acid sequence of SEQ ID NO: 41, HCDR3 comprises or consists of the amino acid sequence of SEQ ID NO: 42, LCDR1 comprises or consists of the amino acid sequence of SEQ ID NO: 37, LCDR2 comprises or consists of the amino acid sequence of SEQ ID NO: 38, and LCDR3 comprises or consists of the amino acid sequence of SEQ ID NO:

39.

25. The dual payload antibody conjugate drug of any one of claims 1 to 23, wherein Ab comprises a heavy chain variable region and a light chain variable region, wherein the heavy chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 10, and wherein the light chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 9; or wherein the heavy chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 22, and wherein the light chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 21 ; or wherein the heavy chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 33, and wherein the light chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 32; or wherein the heavy chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 45, and wherein the light chain variable region comprises the amino acid sequence set forth in SEQ ID NO:

44. ​ ​ ​ ​ ​ wherein the heavy chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 44, and wherein the light chain variable region comprises the amino acid sequence set forth in SEQ ID NO:

43.

26. The dual payload antibody conjugate drug of any one of claims 1 to 23, wherein the Ab comprises: (a) a heavy chain comprising the amino acid sequence of SEQ ID NO: 2, and (b) a light chain comprising the amino acid sequence of SEQ ID NO: 1 ; or (a) a heavy chain comprising the amino acid sequence of SEQ ID NO: 14, and (b) a light chain comprising the amino acid sequence of SEQ ID NO: 13; or (a) a heavy chain comprising the amino acid sequence of SEQ ID NO: 25, and (b) a light chain comprising the amino acid sequence of SEQ ID NO: 24; or (a) a heavy chain comprising the amino acid sequence of SEQ ID NO: 36, and (b) a light chain comprising the amino acid sequence of SEQ ID NO:

35.

27. The dual payload antibody conjugate drug of any one of claims 1 to 23, wherein the Ab is selected from trastuzumab, pertuzumab, margetuximab or HT-19, or an antibody fragment thereof or other anti-human HER2 antibody that recognizes the same epitope or competes for binding to human HER2, preferably trastuzumab; or wherein the Ab is selected from sacituzumab, Datopotamab, or an antibody fragment thereof or other anti-human TROP2 antibody that recognizes the same epitope or competes for binding to human TROP2, preferably sacituzumab; or wherein the Ab is selected from zalutumumab, Osemitamab (TST001), CMG901, ASKB589, ZL-1211, or an antibody fragment thereof, or other anti-human Claudin 18.2 antibody that recognizes the same epitope or competes for binding to human Claudin 18.2, preferably zalutumumab; or wherein the Ab is selected from cetuximab, panitumumab, nimotuzumab, necitumuma, amivantamab, depatuxizumab, NECITUMUMAB, IZALONTAMAB, BAFISONTAMAB, Petosemtamab, PIMURUTAMAB, FUTUXIMAB and MODOTUXIMAB, or an antibody fragment thereof, or other anti-human EGFR antibody that recognizes the same epitope or competes for binding to human EGFR, preferably cetuximab.

28. The dual payload antibody conjugate drug of any one of claims 1 to 23, wherein the Ab is selected from trastuzumab, pertuzumab, margetuximab or HT-19, or an antibody fragment thereof or other anti-human HER2 antibody that recognizes the same epitope or competes for binding to human HER2, preferably trastuzumab; or wherein the Ab is selected from sacituzumab, Datopotamab, or an antibody fragment thereof or other anti-human TROP2 antibody that recognizes the same epitope or competes for binding to human TROP2, preferably sacituzumab; or wherein the Ab is selected from zalutumumab, Osemitamab (TST001), CMG901, ASKB589, ZL-1211, or an antibody fragment thereof, or other anti-human Claudin 18.2 antibody that recognizes the same epitope or competes for binding to human Claudin 18.2, preferably zalutumumab; or wherein the Ab is selected from cetuximab, panitumumab, nimotuzumab, necitumuma, amivantamab, depatuxizumab, NECITUMUMAB, IZALONTAMAB, BAFISONTAMAB, Petosemtamab, PIMURUTAMAB, FUTUXIMAB and MODOTUXIMAB, or an antibody fragment thereof, or other anti-human EGFR antibody that recognizes the same epitope or competes for binding to human EGFR, preferably cetuximab.

28. Dual payload antibody conjugate drug according to any one of claims 1 to 27, wherein q is an integer or non-integer number from 1 to 10 or a range between any two of the numbers 1 to 10, such as about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, about 1 to 2, 1 to 3, 1 to 4, 1 to 5, 1 to 6, 1 to 7, 1 to 8, 1 to 9, 1 to 10, 2 to 10, 2 to 8, 2 to 6, 2 to 4, 3 to 10, 3 to 8, 4 to 6, 4 to 8, 4-10, 6 to 8, or 6 to 10; preferably q is an average DAR value of about 1 to 8 or a range between any two of the numbers 1 to 8, such as about 1, 2, 3, 4, 5, 6, 7, 8, about 1 to 2, 1 to 3, 1 to 4, 1 to 5, 1 to 6, 1 to 7, 1 to 8, 2 to 8, 2 to 6, 2 to 4, 3 to 10, 3 to 8, 4 to 6, 4 to 8, 4 to 10, 6 to 8, or 6 to 10.

29. The dual payload antibody conjugate drug according to claim 1, selected from or a pharmaceutically acceptable salt, ester, isomer, solvate, prodrug or isotopically-labeled version thereof.

30. A linker unit-payload fragment compound of formula (IV), For example wherein: the wavy line indicates the bond to the targeting ligand; D1 is as defined in any one of claims 1 to 11, preferably Further to wherein the asterisks indicate the points of attachment to the linker unit, B1, B2, R1, R1', R2, R2' are as defined in any one of claims 1 to 10; preferably D1 is as defined in claim 11; D2 is as defined in claim 12; G, E, W, P1, P2, A1, A2, S1, S2 are each as defined in any one of claims 13 to 22, respectively; preferably the fragment compound of formula (IV) is a fragment compound of PL-3 to PL-41 and PL-45 to PL-59 as described in the specification.

31. A pharmaceutical composition comprising a dual payload antibody conjugate drug according to any one of claims 1 to 29 and one or more pharmaceutically acceptable excipients.

32. The pharmaceutical composition of claim 31, which is for intravenous, intratumoral, subcutaneous, intramuscular, oral, intranasal, intrathecal, transdermal or topical administration, preferably for intravenous, intraperitoneal, subcutaneous or intramuscular administration.

33. A method of treating or preventing a disease associated with or mediated by STING, including an inflammatory, allergic or autoimmune disease, an infectious disease such as a viral infection or a hyperproliferative disease, comprising administering to a subject in need thereof a therapeutically effective amount of a dual payload antibody conjugate drug according to any one of claims 1-29 or a pharmaceutically acceptable salt, ester, isomer, solvate, prodrug or isotopically-labeled version thereof or a pharmaceutical composition of claim 31 or 32.

34. Use of a dual payload antibody conjugate drug according to any one of claims 1-29 or a pharmaceutically acceptable salt, ester, isomer, solvate, prodrug or isotopically-labeled version thereof or a pharmaceutical composition of claim 31 or 32 for the prevention or treatment of a disease associated with or mediated by STING, more specifically for the treatment or prevention of an inflammatory, allergic or autoimmune disease, an infectious disease such as a viral infection or a hyperproliferative disease.

35. Use of the dual payload antibody conjugate drug of any one of claims 1 to 29 or a pharmaceutically acceptable salt, ester, isomer, solvate, prodrug or isotopically-labeled form thereof or the pharmaceutical composition of claim 31 or 32 for the preparation of a medicament for the prevention or treatment of a disease associated with or mediated by STING, more particularly an inflammatory, allergic or autoimmune disease, an infectious disease such as a viral infection or a hyperproliferative disease.

36. The use of claim 34 or 35, wherein the hyperproliferative disease is a tumor or cancer selected from the group consisting of brain cancer, skin cancer, bladder cancer, ovarian cancer, stomach cancer, pancreatic cancer, prostate cancer, colon cancer, colorectal cancer, blood cancer, lung cancer, bone cancer, neuroblastoma, intestinal cancer such as rectal cancer, colon cancer, colorectal cancer, familial adenomatous polyposis cancer and hereditary non-lymphomatous colorectal cancer, esophageal cancer, lip cancer, laryngeal cancer, nasopharyngeal cancer, pharyngeal squamous cancer, oral cavity cancer, head and neck cancer, salivary gland cancer, peritoneal cancer, soft tissue sarcoma, urothelial cancer, sweat gland carcinoma, gastric cancer, adenocarcinoma, medullary thyroid carcinoma, papillary thyroid carcinoma, kidney cancer, renal parenchymal carcinoma, cervical cancer, uterine body cancer, endometrial cancer, testicular cancer, breast cancer (including HER2-negative breast cancer), urological cancer, melanoma, brain tumors such as glioblastoma, astrocytoma, meningioma, medulloblastoma and peripheral neuroectodermal tumor, lymphoma such as Hodgkin's lymphoma, non-Hodgkin's lymphoma, Burkitt's lymphoma, acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL), chronic myelogenous leukemia (CLL) and lymphocytic cancer, acute myelogenous leukemia (AML), myelogenous leukemia (chronic myelogenous leukemia (CML), adult T-cell lymphoma, diffuse lymphoma (DLBCL), liver cancer, hepatocellular carcinoma, multiple myeloma, seminoma, osteosarcoma, chondrosarcoma, anal canal cancer, renal cell carcinoma, adrenal cortex cancer, chordoma, fallopian tube cancer, gastrointestinal stromal tumor, myeloproliferative disorder, mesothelioma, biliary tract cancer, Ewing's sarcoma and other rare tumor types, and recurrent forms of the above tumors; preferably selected from the group consisting of small cell lung cancer, non-small cell lung cancer, colorectal cancer, liver cancer, breast cancer, ovarian cancer, stomach cancer, prostate cancer, melanoma, renal cell carcinoma, head and neck cancer, soft tissue sarcoma, pancreatic cancer, Hodgkin's lymphoma, leukemia or bladder cancer.

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