Use of Anti-her2 antibody-drug conjugate for treating intestinal cancer

Abstract

An anti-HER2 antibody-drug conjugate for treating intestinal cancer in a subject. A use of the anti-HER2 antibody-drug conjugate in the preparation of a drug for treating intestinal cancer in a subject.

Description

Use of anti-HER2 antibody-drug conjugates in the treatment of colorectal cancer Technical Field

[0001] The present disclosure belongs to the field of biomedicine, and specifically relates to the use of anti-HER2 antibody-drug conjugates (ADCs) in the treatment of colorectal cancer. Background Art

[0002] Human epidermal growth factor receptor 2 (HER2) belongs to the human epidermal growth factor receptor family, which includes EGFR (ErbB-1), HER2 / c-neu (ErbB-2), HER3 (ErbB-3), and HER4 (ErbB-4). These receptors are located on the cell surface and share a similar structure. HER2 is a ubiquitously expressed receptor protein. Abnormal gene amplification leads to protein overexpression, which in turn causes abnormal activation of signaling pathways and is a major driver of solid tumor growth. HER2 can form homodimers and heterodimers with other HER family receptors, leading to phosphorylation of receptor tyrosine residues and activation of multiple signaling pathways, including MPK, PI3K, JAK, STAT3, and PKC, ultimately contributing to cell proliferation and tumorigenesis.

[0003] Anti-HER2 targeted therapy is an important approach to treating colorectal cancer. Therefore, there is an urgent need to explore drugs targeting HER2 to meet the huge clinical demand for colorectal cancer treatment. Summary of the Invention

[0004] Treatments for bowel cancer

[0005] The present disclosure provides a method for treating colorectal cancer in a subject, comprising administering to the subject an anti-HER2 antibody-drug conjugate of the present disclosure. The present disclosure also provides a method for treating colorectal cancer in a subject as a third-line treatment or later, comprising administering to the subject an anti-HER2 antibody-drug conjugate of the present disclosure. In some embodiments, in the method, the anti-HER2 antibody-drug conjugate is administered in a therapeutically effective amount.

[0006] The present disclosure also provides use of the anti-HER2 antibody-drug conjugate of the present disclosure in preparing a medicament for treating colorectal cancer in a subject. The present disclosure also provides use of the anti-HER2 antibody-drug conjugate of the present disclosure in preparing a medicament for third-line or later-line treatment of colorectal cancer in a subject. In some embodiments, the medicament comprises a therapeutically effective amount of the anti-HER2 antibody-drug conjugate.

[0007] The present disclosure also provides use of the anti-HER2 antibody-drug conjugate of the present disclosure for treating colorectal cancer in a subject.

[0008] The present disclosure also provides an anti-HER2 antibody drug conjugate of the present disclosure for use in treating colorectal cancer in a subject. The present disclosure also provides an anti-HER2 antibody drug conjugate of the present disclosure for use as a third-line treatment or later-line treatment for colorectal cancer in a subject. In some embodiments, the anti-HER2 antibody drug conjugate is administered to a subject in a therapeutically effective amount.

[0009] In some embodiments, in the method or use, the anti-HER2 antibody drug conjugate is administered once every 1 week (q1w), every 2 weeks (q2w), every 3 weeks (q3w), or every 4 weeks (q4w). In a specific embodiment, in the method or use, the anti-HER2 antibody drug conjugate is administered once every 3 weeks. In some embodiments, in the method or use, the anti-HER2 antibody drug conjugate is administered at a dose of 1.5-9 mg / kg, 4.5-7.5 mg / kg, or 6-7.5 mg / kg each time. In some embodiments, in the method or use, the anti-HER2 antibody drug conjugate is administered at a dose of 1.5 mg / kg, 3 mg / kg, 4.5 mg / kg, 5 mg / kg, 6 mg / kg, 7.5 mg / kg, 9 mg / kg, or a range formed by any of the above values. In some embodiments, in the method or use, the anti-HER2 antibody drug conjugate is administered at a dose of 6 mg / kg or 7.5 mg / kg each time. In some embodiments, in the methods or uses, the anti-HER2 antibody drug conjugate is administered at a dose of 6 mg / kg each time. In some embodiments, in the methods or uses, the anti-HER2 antibody drug conjugate is administered at a dose of 7.5 mg / kg each time. In some embodiments, in the methods or uses, the anti-HER2 antibody drug conjugate is administered once every 1 week, every 2 weeks, every 3 weeks, or every 4 weeks, each time at a dose of 1.5-9 mg / kg, 4.5-7.5 mg / kg, or 6-7.5 mg / kg anti-HER2 antibody drug conjugate. In some embodiments, in the methods or uses, the anti-HER2 antibody drug conjugate is administered once every 3 weeks, each time at a dose of 1.5 mg / kg, 3 mg / kg, 4.5 mg / kg, 5 mg / kg, 6 mg / kg, 7.5 mg / kg or 9 mg / kg anti-HER2 antibody drug conjugate. In some embodiments, in the methods or uses, the anti-HER2 antibody drug conjugate is administered once every 3 weeks at a dose of 6 mg / kg or 7.5 mg / kg of the anti-HER2 antibody drug conjugate. In some embodiments, in the methods or uses, the anti-HER2 antibody drug conjugate is administered once every 3 weeks at a dose of 6 mg / kg of the anti-HER2 antibody drug conjugate. In some embodiments, in the methods or uses, the anti-HER2 antibody drug conjugate is administered once every 3 weeks at a dose of 7.5 mg / kg of the anti-HER2 antibody drug conjugate.

[0010] In some embodiments, in the methods or uses, one treatment cycle is one week, ... In some embodiments, in the methods or uses, one treatment cycle is 3 weeks, and 6 mg / kg of anti-HER2 antibody drug conjugate is administered in each treatment cycle. In some embodiments, in the methods or uses, one treatment cycle is 3 weeks, and 6 mg / kg of anti-HER2 antibody drug conjugate is administered on day 1 of each treatment cycle. In some embodiments, in the methods or uses, one treatment cycle is 3 weeks, and 7.5 mg / kg of anti-HER2 antibody drug conjugate is administered in each treatment cycle. In some embodiments, in the methods or uses, one treatment cycle is 3 weeks, and 7.5 mg / kg of anti-HER2 antibody drug conjugate is administered on day 1 of each treatment cycle.

[0011] The anti-HER2 antibody drug conjugate can be formulated with one or more pharmaceutically acceptable excipients to form a suitable pharmaceutical composition (or preparation). The pharmaceutical composition can be a suitable dosage form. In some embodiments, the anti-HER2 antibody drug conjugate is formulated as a preparation for parenteral administration. In some specific embodiments, the anti-HER2 antibody drug conjugate is formulated as a preparation for intravenous or intramuscular administration. In some specific embodiments, the anti-HER2 antibody drug conjugate can be formulated as an injection. In some specific embodiments, the anti-HER2 antibody drug conjugate is formulated as a preparation for intravenous injection or infusion.

[0012] In some embodiments, in the method or use, the anti-HER2 antibody drug conjugate is administered by intravenous infusion.

[0013] In the method or use, the dosing regimen (e.g., dosing cycle, dosing time, dosage and dosage adjustment) of the anti-HER2 antibody drug conjugate can be adjusted according to the severity of the disease, the response of the disease, any treatment-related toxicity, the age and health status of the patient. For example, the anti-HER2 antibody drug conjugate can be delayed for 1-56 days, for example, for 1 week, 2 weeks, 3 weeks, 4 weeks, 5 weeks, 6 weeks, 7 weeks or 8 weeks. For another example, the dosage of the anti-HER2 antibody drug conjugate can be adjusted from 6 mg / kg to 4.5 mg / kg or 5 mg / kg, or from 7.5 mg / kg to 6 mg / kg.

[0014] In some embodiments, the intestinal cancer is unresectable, refractory, advanced, recurrent and / or metastatic intestinal cancer. In some embodiments, the intestinal cancer is unresectable intestinal cancer. In some embodiments, the intestinal cancer is refractory intestinal cancer. In some embodiments, the intestinal cancer is advanced intestinal cancer. In some embodiments, the intestinal cancer is locally advanced intestinal cancer. In some embodiments, the intestinal cancer is recurrent and / or metastatic intestinal cancer. In some embodiments, the intestinal cancer is recurrent intestinal cancer. In some embodiments, the intestinal cancer is metastatic intestinal cancer. In some embodiments, the intestinal cancer is unresectable locally advanced or distant metastatic intestinal cancer. In some embodiments, the intestinal cancer is unresectable locally advanced intestinal cancer. In some embodiments, the intestinal cancer is distant metastatic intestinal cancer.

[0015] In some embodiments, the colorectal cancer is a colorectal cancer expressing HER2. In some embodiments, the colorectal cancer is a HER2-positive colorectal cancer. In some embodiments, the HER2-positive colorectal cancer is a colorectal cancer whose HER2 expression is 3+ (i.e., IHC 3+) as determined by immunohistochemistry (IHC). In some embodiments, the HER2-positive colorectal cancer is a colorectal cancer whose HER2 expression is 2+ as determined by IHC and whose HER2 expression is positive by ISH (i.e., IHC 2+ and ISH+).

[0016] In some embodiments, the bowel cancer is HER2-positive, unresectable bowel cancer. In some embodiments, the bowel cancer is HER2-positive, advanced bowel cancer. In some embodiments, the bowel cancer is HER2-positive, locally advanced bowel cancer. In some embodiments, the bowel cancer is advanced bowel cancer with a HER2 expression of 3+ as determined by IHC. In some embodiments, the bowel cancer is locally advanced bowel cancer with a HER2 expression of 3+ as determined by IHC. In some embodiments, the bowel cancer is HER2-positive, metastatic bowel cancer. In some embodiments, the bowel cancer is metastatic bowel cancer with a HER2 expression of 3+ as determined by IHC. In some embodiments, the bowel cancer is HER2-positive, unresectable, locally advanced or distant metastatic bowel cancer. In some embodiments, the bowel cancer is unresectable, locally advanced or distant metastatic bowel cancer with a HER2 expression of 3+ as determined by IHC. In some embodiments, the bowel cancer is HER2-positive, unresectable, locally advanced bowel cancer. In some embodiments, the bowel cancer is unresectable, locally advanced bowel cancer with a HER2 expression of 3+ as determined by IHC. In some embodiments, the colorectal cancer is a HER2-positive distant metastatic colorectal cancer. In some embodiments, the colorectal cancer is a distant metastatic colorectal cancer with HER2 expression as 3+ as determined by IHC.

[0017] In some embodiments, the subject with intestinal cancer has been previously treated for intestinal cancer (e.g., treatment failure or intolerance). In some embodiments, the subject with intestinal cancer has previously received at least two lines of treatment for intestinal cancer (e.g., treatment failure or intolerance). In some embodiments, the subject with intestinal cancer has previously received at least three lines of treatment for intestinal cancer (e.g., treatment failure or intolerance).

[0018] In some embodiments, the subject is a subject with colorectal cancer who has previously failed treatment with a HER2-targeted drug. In some embodiments, the subject is a subject with colorectal cancer who has previously failed treatment with a VEGFR-targeted drug. In some embodiments, the subject is a subject with HER2-positive colorectal cancer who has previously failed treatment with a HER2-targeted drug. In some embodiments, the subject is a subject with HER2-positive colorectal cancer who has previously failed treatment with a VEGFR-targeted drug. In some embodiments, the subject is a subject with advanced HER2-positive colorectal cancer who has previously failed treatment with a HER2-targeted drug. In some embodiments, the subject is a subject with advanced HER2-positive colorectal cancer who has previously failed treatment with a VEGFR-targeted drug. In some embodiments, the subject is a subject with locally advanced HER2-positive colorectal cancer who has previously failed treatment with a HER2-targeted drug. In some embodiments, the subject is a subject with locally advanced HER2-positive colorectal cancer who has previously failed treatment with a HER2-targeted drug. In some embodiments, the subject is a subject with locally advanced HER2-positive colorectal cancer who has previously failed treatment with a HER2-targeted drug. In some embodiments, the subject is a subject with locally advanced HER2-positive colorectal cancer who has previously failed treatment with a VEGFR-targeted drug. In some embodiments, the subject is a subject with unresectable locally advanced HER2-positive colorectal cancer who has previously failed treatment with a HER2-targeted drug. In some embodiments, the subject is a subject with HER2-positive, unresectable, locally advanced colorectal cancer who has previously failed VEGFR-targeted drug therapy. In some embodiments, the subject is a subject with HER2-positive, distant metastatic colorectal cancer who has previously failed HER2-targeted drug therapy. In some embodiments, the subject is a subject with HER2-positive, distant metastatic colorectal cancer who has previously failed VEGFR-targeted drug therapy. In some embodiments, the subject is a subject with unresectable, locally advanced colorectal cancer whose HER2 expression is 3+ as determined by IHC and who has previously failed HER2-targeted drug therapy. In some embodiments, the subject is a subject with unresectable, locally advanced colorectal cancer whose HER2 expression is 3+ as determined by IHC and who has previously failed VEGFR-targeted drug therapy. In some embodiments, the subject is a subject with HER2 expression is 3+ as determined by IHC and who has previously failed HER2-targeted drug therapy. In some embodiments, the subject is a subject with distant metastatic colorectal cancer whose HER2 expression is 3+ as determined by IHC and who has previously failed HER2-targeted drug therapy. In some embodiments, the subject is a subject with distant metastatic colorectal cancer whose HER2 expression is 3+ as determined by IHC and who has previously failed VEGFR-targeted drug therapy. In some embodiments, the subject is a subject with unresectable locally advanced colorectal cancer whose HER2 expression is 3+ as determined by IHC and who has previously failed treatment with a HER2-targeted drug. In some embodiments, the subject is a subject with unresectable locally advanced colorectal cancer whose HER2 expression is 3+ as determined by IHC and who has previously failed treatment with a VEGFR-targeted drug. In some embodiments, the subject is a subject with distant metastatic colorectal cancer whose HER2 expression is 3+ as determined by IHC and who has previously failed treatment with a HER2-targeted drug.In some embodiments, the subject is a subject with distant metastatic colorectal cancer whose HER2 expression is 3+ as determined by IHC and who has failed previous VEGFR targeted drug treatment.

[0019] In some embodiments, the subject is a subject with colorectal cancer who has previously failed treatment with one or more of an anti-HER2 ADC (including any currently marketed anti-HER2 ADC), trastuzumab, pertuzumab, pyrotinib, lapatinib, regorafenib, fruquintinib, bevacizumab, or cetuximab. In some embodiments, the subject is a subject with HER2-positive colorectal cancer who has previously failed treatment with one or more of an anti-HER2 ADC, trastuzumab, pertuzumab, pyrotinib, lapatinib, regorafenib, fruquintinib, bevacizumab, or cetuximab. In some embodiments, the subject is a subject with advanced HER2-positive colorectal cancer who has previously failed treatment with one or more of an anti-HER2 ADC, trastuzumab, pertuzumab, pyrotinib, lapatinib, regorafenib, fruquintinib, bevacizumab, or cetuximab. In some embodiments, the subject is a subject with HER2-positive locally advanced colorectal cancer who has previously failed treatment with one or more of an anti-HER2 ADC, trastuzumab, pertuzumab, pyrotinib, lapatinib, regorafenib, fruquintinib, bevacizumab, or cetuximab. In some embodiments, the subject is a subject with HER2-positive unresectable locally advanced colorectal cancer who has previously failed treatment with one or more of an anti-HER2 ADC, trastuzumab, pertuzumab, pyrotinib, lapatinib, regorafenib, fruquintinib, bevacizumab, or cetuximab. In some embodiments, the subject is a subject with HER2-positive distant metastatic colorectal cancer who has previously failed treatment with one or more of an anti-HER2 ADC, trastuzumab, pertuzumab, pyrotinib, lapatinib, regorafenib, fruquintinib, bevacizumab, or cetuximab. In some embodiments, the subject is a subject with unresectable locally advanced colorectal cancer whose HER2 expression is 3+ as determined by IHC, who has previously failed treatment with one or more of an anti-HER2 ADC, trastuzumab, pertuzumab, pyrotinib, lapatinib, regorafenib, fruquintinib, bevacizumab, or cetuximab. In some embodiments, the subject is a subject with distant metastatic colorectal cancer whose HER2 expression is 3+ as determined by IHC, who has previously failed treatment with one or more of an anti-HER2 ADC, trastuzumab, pertuzumab, pyrotinib, lapatinib, regorafenib, fruquintinib, bevacizumab, or cetuximab. In some embodiments, the subject is a subject with unresectable locally advanced colorectal cancer whose HER2 expression is 3+ as determined by IHC, who has failed previous treatment with one or more of anti-HER2 ADC, trastuzumab, pertuzumab, pyrotinib, lapatinib, regorafenib, fruquintinib, bevacizumab, and cetuximab.In some embodiments, the subject is a subject with distant metastatic colorectal cancer whose HER2 expression is 3+ as determined by IHC, who has failed previous treatment with one or more of anti-HER2 ADC, trastuzumab, pertuzumab, pyrotinib, lapatinib, regorafenib, fruquintinib, bevacizumab, and cetuximab.

[0020] In some embodiments, the subject of the intestinal cancer has received standard treatment to treat intestinal cancer (for example, treatment failure or intolerance). In some embodiments, the subject of the intestinal cancer has received standard treatment to treat intestinal cancer in the past, and disease progression or intolerance occur during treatment or after the end of treatment. In some embodiments, the subject of the intestinal cancer has received standard treatment to treat intestinal cancer in the past, and disease progression or intolerance occur within 3 months (for example 1, 2 or 3 months) during treatment or after the end of treatment. In some embodiments, the subject of the intestinal cancer has received chemotherapy to treat intestinal cancer (for example, treatment failure or intolerance). In some embodiments, the subject of the intestinal cancer has received standard chemotherapy to treat intestinal cancer (for example, treatment failure or intolerance). In some embodiments, the standard treatment includes administering to the subject including but not limited to fluorouracil or its derivatives, oxaliplatin and / or irinotecan. In some embodiments, the standard chemotherapy includes administering to the subject including but not limited to fluorouracil or its derivatives, oxaliplatin and / or irinotecan. In some embodiments, the subject of intestinal cancer has previously received fluorouracil or its derivatives, oxaliplatin and / or irinotecan to treat intestinal cancer (e.g., treatment failure or intolerance). In some embodiments, the subject is a subject with intestinal cancer that has failed to be treated with 5-fluorouracil drugs, oxaliplatin and / or irinotecan. In some embodiments, the subject is a subject with HER2-positive intestinal cancer that has failed to be treated with 5-fluorouracil drugs, oxaliplatin and / or irinotecan. In some embodiments, the subject is a subject with intestinal cancer that has failed to be treated with 5-fluorouracil drugs, oxaliplatin and / or irinotecan and has an expression of HER2 of 3+ as determined by IHC. In some embodiments, the subject is a subject with advanced intestinal cancer that has failed to be treated with 5-fluorouracil drugs, oxaliplatin and / or irinotecan and has an expression of HER2 of 3+ as determined by IHC. In some embodiments, the subject is a subject with advanced colorectal cancer whose expression of HER2 that has failed to be treated with 5-fluorouracil drugs, oxaliplatin and / or irinotecan is 3+. In some embodiments, the subject of the intestinal cancer has received adjuvant therapy to treat intestinal cancer (for example, treatment failure or intolerance) in the past. In some embodiments, the subject of the intestinal cancer has received adjuvant therapy to treat intestinal cancer in the past, and disease progression occurs during or after the end of treatment. In some embodiments, the subject of the intestinal cancer has received adjuvant therapy to treat intestinal cancer (for example, treatment failure or intolerance) in the past, and the adjuvant therapy includes administering oxaliplatin to the subject. In some embodiments, the subject of the intestinal cancer has received adjuvant therapy to treat intestinal cancer in the past, and the adjuvant therapy includes administering oxaliplatin to the subject, and disease progression occurs within 6 months (for example 1, 2, 3, 4, 5 or 6 months) during or after the end of treatment.In some embodiments, the intolerance is hematological toxicity reaching Grade 4. Hematological toxicity includes but is not limited to neutropenia, decreased white blood cell count, anemia, decreased lymphocyte count, and decreased platelet count. In some embodiments, the intolerance is decreased platelet count reaching Grade 3 or above. In some embodiments, the intolerance is non-hematological toxicity reaching Grade 3 or above.

[0021] In some embodiments, the subject with intestinal cancer has previously received localized radiation therapy to treat intestinal cancer. In some embodiments, the subject with intestinal cancer has previously received localized radiation therapy to treat intestinal cancer, and the localized radiation therapy was more than 2 weeks from the first administration of the anti-HER2 antibody drug conjugate, and the lesion targeted by the anti-HER2 antibody drug conjugate is not within the localized radiation therapy area. In some embodiments, the subject with intestinal cancer has previously received localized radiation therapy to treat intestinal cancer, and the localized radiation therapy was more than 2 weeks from the first administration of the anti-HER2 antibody drug conjugate, and the disease has progressed. In some embodiments, the localized radiation therapy is palliative radiation therapy or brain radiation therapy.

[0022] In some embodiments, the intestinal cancer is sigmoid colon cancer, colon cancer, rectal cancer or colorectal cancer. In some embodiments, the intestinal cancer is bulge-type intestinal cancer, ulcerative intestinal cancer or invasive intestinal cancer.

[0023] In some embodiments, the colorectal cancer is stage I, stage II, stage III or stage IV colorectal cancer according to the TNM staging standard.

[0024] Anti-HER2 Antibody Drug Conjugates

[0025] The anti-HER2 antibody drug conjugate used in the present disclosure is formed by connecting a drug-linker having a structure shown in the following formula Ia to an antigen-binding construct targeting HER2:

[0026] in,

[0027] The 3-position of -(succinimide-3-yl-N)- in Formula Ia (i.e., The position of the connection) is connected to the antigen binding construct targeting HER2,

[0028] The HER2-targeting antigen-binding construct comprises a first antigen-binding fragment and a second antigen-binding fragment, wherein the first antigen-binding fragment comprises: a heavy chain CDR1 (HCDR1) comprising the amino acid sequence of SEQ ID NO: 1, a HCDR2 comprising the amino acid sequence of SEQ ID NO: 2, a HCDR3 comprising the amino acid sequence of SEQ ID NO: 3, a light chain CDR1 (LCDR1) comprising the amino acid sequence of SEQ ID NO: 4, a LCDR2 comprising the amino acid sequence of SEQ ID NO: 5, and a LCDR3 comprising the amino acid sequence of SEQ ID NO: 6, and the second antigen-binding fragment comprises: a HCDR1 comprising the amino acid sequence of SEQ ID NO: 9, a HCDR2 comprising the amino acid sequence of SEQ ID NO: 10, a HCDR3 comprising the amino acid sequence of SEQ ID NO: 11, a LCDR1 comprising the amino acid sequence of SEQ ID NO: 12, a LCDR2 comprising the amino acid sequence of SEQ ID NO: 13, and a LCDR3 comprising the amino acid sequence of SEQ ID NO: 14.

[0029] In some embodiments, the 3-position of the -(succinimidyl-3-yl-N)- is linked to the antigen-binding construct targeting HER2 through a thioether bond.

[0030] In some embodiments, the anti-HER2 antibody drug conjugate has an average number of drug-linker connections per antigen-binding construct targeting HER2 of 2 to 8. In some embodiments, the anti-HER2 antibody drug conjugate has an average number of drug-linker connections per antigen-binding construct targeting HER2 of 4 to 7. In some embodiments, the anti-HER2 antibody drug conjugate has an average number of drug-linker connections per antigen-binding construct targeting HER2 of 5 to 6. In some embodiments, the anti-HER2 antibody drug conjugate has an average number of drug-linker connections per antigen-binding construct targeting HER2 of 5.5 to 6. In some embodiments, the anti-HER2 antibody drug conjugate has an average number of drug-linker connections per antigen-binding construct targeting HER2 of 5.8 to 6.

[0031] Table 1. CDR sequences of exemplary antigen-binding constructs targeting HER2

[0032] It will be understood by those skilled in the art that, unless otherwise specified, the term "CDR" or "complementarity determining region" of a given antigen-binding fragment or region thereof (e.g., variable region) should be understood to encompass complementarity determining regions defined by any known scheme. Although the CDRs claimed in the present disclosure are based on the sequences shown in Table 1 (one definition), amino acid sequences corresponding to other CDR definition rules (e.g., one or more combinations of the AbM, CCG, Kabat, Chothia, IMGT, or Contact definitions known in the art) should also fall within the scope of protection of the present disclosure.

[0033] In some embodiments, the first antigen-binding fragment comprises a heavy chain variable region having an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:7, and a light chain variable region having an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:8. In some embodiments, the first antigen-binding fragment comprises a heavy chain variable region having the amino acid sequence of SEQ ID NO: 7, and a light chain variable region having the amino acid sequence of SEQ ID NO: 8. In some specific embodiments, the amino acid sequence of the heavy chain variable region of the first antigen-binding fragment is as shown in SEQ ID NO: 7, and the amino acid sequence of the light chain variable region is as shown in SEQ ID NO: 8.

[0034] In some embodiments, the first antigen-binding fragment comprises a heavy chain variable region and a light chain variable region, wherein the heavy chain variable region comprises a HCDR1 having the amino acid sequence of SEQ ID NO: 1, a HCDR2 having the amino acid sequence of SEQ ID NO: 2, and a HCDR3 having the amino acid sequence of SEQ ID NO: 3, the light chain variable region comprises a LCDR1 having the amino acid sequence of SEQ ID NO: 4, a LCDR2 having the amino acid sequence of SEQ ID NO: 5, and a LCDR3 having the amino acid sequence of SEQ ID NO: 6, and the heavy chain variable region comprises an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to SEQ ID NO: 7, and the light chain variable region comprises an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to SEQ ID NO: 8, NO:8 has an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical.

[0035] In some embodiments, the different amino acids in the amino acid sequence having at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identity to the amino acid sequence set forth in SEQ ID NO:7 or SEQ ID NO:8 are located in the FR regions.

[0036] In some embodiments, the second antigen-binding fragment comprises a heavy chain variable region having an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:15, and a light chain variable region having an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:16. In some embodiments, the second antigen-binding fragment comprises a heavy chain variable region having the amino acid sequence of SEQ ID NO: 15, and a light chain variable region having the amino acid sequence of SEQ ID NO: 16. In some specific embodiments, the amino acid sequence of the heavy chain variable region of the second antigen-binding fragment is as shown in SEQ ID NO: 15, and the amino acid sequence of the light chain variable region is as shown in SEQ ID NO: 16.

[0037] In some embodiments, the second antigen-binding fragment comprises a heavy chain variable region and a light chain variable region, wherein the heavy chain variable region comprises a HCDR1 having the amino acid sequence of SEQ ID NO:9, a HCDR2 having the amino acid sequence of SEQ ID NO:10, and a HCDR3 having the amino acid sequence of SEQ ID NO:11, the light chain variable region comprises a LCDR1 having the amino acid sequence of SEQ ID NO:12, a LCDR2 having the amino acid sequence of SEQ ID NO:13, and a LCDR3 having the amino acid sequence of SEQ ID NO:14, and the heavy chain variable region comprises an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to SEQ ID NO:15, and the light chain variable region comprises an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to SEQ ID NO:15, NO:16 has an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical.

[0038] In some embodiments, the different amino acids in the amino acid sequence having at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identity with the amino acid sequence set forth in SEQ ID NO: 15 or SEQ ID NO: 16 are located in the FR regions.

[0039] In some embodiments, the HER2-targeting antigen-binding construct may further comprise an immunoglobulin constant region, or a fragment, analog, variant, or derivative of the constant region. In some embodiments, the constant region comprises a heavy chain constant region and a light chain constant region. In some embodiments, the heavy chain constant region is derived from a human immunoglobulin heavy chain, such as IgG1, IgG2, IgG3, and IgG4 or other classes of immunoglobulin heavy chains, preferably IgG1 heavy chains. In some embodiments, the light chain constant region is derived from a human immunoglobulin light chain, such as a kappa light chain or a lambda light chain of a human immunoglobulin. In some embodiments, the constant region may comprise any modification described herein, such as insertion, deletion, substitution, or chemical modification of amino acids. In some embodiments, the C-terminal lysine of the heavy chain constant region may be present or absent, and deletion of the C-terminal lysine of the heavy chain constant region typically occurs during recombinant expression. In some embodiments, the constant region comprises a mutation that alters effector function. In some embodiments, any amino acid residue in the constant region may be substituted with an amino acid residue of any allotype.

[0040] In some embodiments, the antigen-binding construct targeting HER2 comprises a first polypeptide chain having an amino acid sequence at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 17, a second polypeptide chain having an amino acid sequence at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 18, and a second polypeptide chain having an amino acid sequence at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO: NO: 19 has at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identity to a third polypeptide chain. In some embodiments, the antigen-binding construct targeting HER2 comprises a first polypeptide chain having an amino acid sequence as set forth in SEQ ID NO: 17, a second polypeptide chain having an amino acid sequence as set forth in SEQ ID NO: 18, and a third polypeptide chain having an amino acid sequence as set forth in SEQ ID NO: 19. In some specific embodiments, the antigen-binding construct targeting HER2 consists of three polypeptide chains, wherein the amino acid sequence of the first polypeptide chain is as set forth in SEQ ID NO: 17, the amino acid sequence of the second polypeptide chain is as set forth in SEQ ID NO: 18, and the amino acid sequence of the third polypeptide chain is as set forth in SEQ ID NO: 19.

[0041] In some embodiments, the antigen-binding construct targeting HER2 comprises a first polypeptide chain, a second polypeptide chain, and a third polypeptide chain, wherein the first polypeptide chain comprises a HCDR1 having an amino acid sequence as shown in SEQ ID NO: 1, a HCDR2 having an amino acid sequence as shown in SEQ ID NO: 2, a HCDR3 having an amino acid sequence as shown in SEQ ID NO: 3, a LCDR1 having an amino acid sequence as shown in SEQ ID NO: 4, a LCDR2 having an amino acid sequence as shown in SEQ ID NO: 5, and a LCDR3 having an amino acid sequence as shown in SEQ ID NO: 6; the second polypeptide chain comprises a HCDR1 having an amino acid sequence as shown in SEQ ID NO: 9, a HCDR2 having an amino acid sequence as shown in SEQ ID NO: 10, and a HCDR3 having an amino acid sequence as shown in SEQ ID NO: 11; the third polypeptide chain comprises a LCDR1 having an amino acid sequence as shown in SEQ ID NO: 12, a LCDR2 having an amino acid sequence as shown in SEQ ID NO: 13, and a LCDR3 having an amino acid sequence as shown in SEQ ID NO: 14, and the first polypeptide chain comprises a HCDR1 having an amino acid sequence as shown in SEQ ID NO: 15, a LCDR2 having an amino acid sequence as shown in SEQ ID NO: 16, and a LCDR3 having an amino acid sequence as shown in SEQ ID NO: 17. NO:17, the first polypeptide chain comprises an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO:18, the second polypeptide chain comprises an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO:19, the third polypeptide chain comprises an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO:20 The amino acid sequence shown in NO:19 has an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical.

[0042] In some embodiments, the C-terminal lysine of the amino acid sequence set forth in SEQ ID NO: 17 is deleted, as shown in SEQ ID NO: 20. In some embodiments, the C-terminal lysine of the amino acid sequence set forth in SEQ ID NO: 18 is deleted, as shown in SEQ ID NO: 21. In some embodiments, the C-terminal lysine of the first and second polypeptide chains is deleted, the amino acid sequence of the first polypeptide chain is shown in SEQ ID NO: 20, and the amino acid sequence of the second polypeptide chain is shown in SEQ ID NO: 21.

[0043] In some embodiments, the different amino acids in the amino acid sequence having at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identity with the amino acid sequence set forth in SEQ ID NO: 17, 18 or 19 are located in the FR region or the constant region.

[0044] In other embodiments, the antigen-binding construct targeting HER2 is selected from Expi Her2-1, Expi Her2-3, Expi Her2-4, Expi Her2-5, 23C2 Her2-1, 23C2 Her2-3, 23C2 Her2-4 or 23C2 Her2-5 (see WO2021219046 or CN115279791A). In other embodiments, the antigen-binding construct targeting HER2 is selected from Zanidatamab (ZW25), KN026, MBS301, KM257 or BCD-147.

[0045] The anti-HER2 antibody drug conjugate used in the present disclosure can also be represented by the structure shown in the following formula II:

[0046] Wherein, the antigen-binding construct targeting HER2 is as described above. In some embodiments, the drug-linker is connected to the antigen-binding construct targeting HER2 via a thioether bond (position 3 of -(succinimide-3-yl-N)-). n has the same meaning as DAR and represents the average number of cytotoxic drug connections per antigen-binding construct targeting HER2. In some embodiments, n is 2 to 8. In some embodiments, n is 4 to 7. In some embodiments, n is 5 to 6. In some embodiments, n is 5.5 to 6. In some embodiments, n is 5.8 to 6.

[0047] The antibody drug conjugate preferably used in the present disclosure is formed by connecting a drug-linker having a structure shown in the following formula Ia to an antigen-binding construct targeting HER2:

[0048] in,

[0049] The 3-position of -(succinimide-3-yl-N)- in Formula Ia is linked to an antigen-binding construct targeting HER2,

[0050] The antigen-binding construct targeting HER2 is composed of three polypeptide chains, the amino acid sequence of the first polypeptide chain is as shown in SEQ ID NO: 17 or a variant thereof with a C-terminal lysine deleted, the amino acid sequence of the second polypeptide chain is as shown in SEQ ID NO: 18 or a variant thereof with a C-terminal lysine deleted, and the amino acid sequence of the third polypeptide chain is as shown in SEQ ID NO: 19 (for example, the amino acid sequence of the first polypeptide chain is as shown in SEQ ID NO: 17, the amino acid sequence of the second polypeptide chain is as shown in SEQ ID NO: 18, and the amino acid sequence of the third polypeptide chain is as shown in SEQ ID NO: 19; or the amino acid sequence of the first polypeptide chain is as shown in SEQ ID NO: 20, the amino acid sequence of the second polypeptide chain is as shown in SEQ ID NO: 21, and the amino acid sequence of the third polypeptide chain is as shown in SEQ ID NO: 19; or the amino acid sequence of the first polypeptide chain is as shown in SEQ ID NO: 20, the amino acid sequence of the second polypeptide chain is as shown in SEQ ID NO: 18, and the amino acid sequence of the third polypeptide chain is as shown in SEQ ID NO: 19; or the amino acid sequence of the first polypeptide chain is as shown in SEQ ID NO: 17, the amino acid sequence of the second polypeptide chain is as shown in SEQ ID NO: 18, and the amino acid sequence of the third polypeptide chain is as shown in SEQ ID NO: 19; NO:21, and the amino acid sequence of the third polypeptide chain is shown in SEQ ID NO:19), and

[0051] For one HER2-targeting antigen-binding construct, the average number of drug-linker connections was 5 to 6.

[0052] In some embodiments, the 3-position of -(succinimidyl-3-yl-N)- in Formula Ia is linked to the antigen-binding construct targeting HER2 through a thioether bond.

[0053] The antibody drug conjugates preferably used in the present disclosure can also be represented by the structure shown in the following formula II:

[0054] Where n is 5 to 6,

[0055] The HER2-targeting antigen-binding construct is composed of three polypeptide chains, the amino acid sequence of the first polypeptide chain is as shown in SEQ ID NO: 17 or a variant thereof with a C-terminal lysine deleted, the amino acid sequence of the second polypeptide chain is as shown in SEQ ID NO: 18 or a variant thereof with a C-terminal lysine deleted, and the amino acid sequence of the third polypeptide chain is as shown in SEQ ID NO: 19 (for example, the amino acid sequence of the first polypeptide chain is as shown in SEQ ID NO: 17, the amino acid sequence of the second polypeptide chain is as shown in SEQ ID NO: 18, and the amino acid sequence of the third polypeptide chain is as shown in SEQ ID NO: 19; or the amino acid sequence of the first polypeptide chain is as shown in SEQ ID NO: 20, the amino acid sequence of the second polypeptide chain is as shown in SEQ ID NO: 21, and the amino acid sequence of the third polypeptide chain is as shown in SEQ ID NO: 19; or the amino acid sequence of the first polypeptide chain is as shown in SEQ ID NO: 20, the amino acid sequence of the second polypeptide chain is as shown in SEQ ID NO: 18, and the amino acid sequence of the third polypeptide chain is as shown in SEQ ID NO: 19; or the amino acid sequence of the first polypeptide chain is as shown in SEQ ID NO: 17, the amino acid sequence of the second polypeptide chain is as shown in SEQ ID NO: 18, and the amino acid sequence of the third polypeptide chain is as shown in SEQ ID NO: 19; (See SEQ ID NO: 21, and the amino acid sequence of the third polypeptide chain is shown in SEQ ID NO: 19.) In some embodiments, the drug-linker is linked to the HER2-targeting antigen-binding construct via a thioether bond.

[0056] In other specific embodiments, the anti-HER2 antibody drug conjugates disclosed herein are selected from MRG002, ARX788, A166, SHR-A1811, BB-1701, SYD985, FS-1502, or BAT8001.

[0057] The anti-HER2 antibody-drug conjugates disclosed herein also include isomers, pharmaceutically acceptable salts, or solvates of the anti-HER2 antibody-drug conjugates, their isomers, or their pharmaceutically acceptable salts.

[0058] Technical Effects

[0059] Administration of the anti-HER2 antibody drug conjugates disclosed herein has one or more of the following effects:

[0060] (1) Producing benefits to subjects with colorectal cancer, preferably unresectable locally advanced colorectal cancer or metastatic colorectal cancer (e.g., distant metastatic colorectal cancer);

[0061] (2) Good safety;

[0062] (3) It is well tolerated in the subjects.

[0063] Definition and Description

[0064] Unless otherwise indicated, the following terms used in this disclosure have the following meanings. A particular term should not be construed as undefined or unclear unless specifically defined, but rather should be understood according to its ordinary meaning in the art. When a trade name appears in this disclosure, it is intended to refer to the corresponding commercial product or its active ingredient.

[0065] As used herein, the structure of "-(succinimidyl-3-yl-N)-" is as follows:

[0066] Unless otherwise specified, use a solid wedge key. and dotted wedge key Indicates the absolute configuration of a stereocenter.

[0067] Unless otherwise specified, when a group has a linkable site, the link between that site and other groups can be represented by a wavy line. express.

[0068] The term "antigen binding construct" refers to any agent capable of binding to an antigen, such as a polypeptide or polypeptide complex. In some aspects, an antigen binding construct is a polypeptide that specifically binds to a target antigen. An antigen binding construct can be a monomer, dimer, multimer, protein, peptide, protein or peptide complex, antibody, or antigen binding fragment thereof, etc. An antigen binding construct can be a monospecific, bispecific, or multispecific polypeptide construct. In some aspects, an antigen binding construct can include, for example, one or more antigen binding fragments (e.g., Fab or scFv) connected to one or more Fc.

[0069] The "antigen-binding fragment" of an antibody refers to one or more fragments of an antibody that retain the function of specifically binding to an antigen (e.g., HER2 protein). It has been demonstrated that the antigen-binding function of an antibody can be implemented by a fragment of a full-length antibody. Examples encompassed within the term "antigen-binding fragment" of an antibody include: (i) a Fab fragment: a monovalent fragment consisting of a VL, VH, CL, and CH1 domains; (ii) a F(ab')2 fragment, a bivalent fragment comprising two Fab fragments connected by a disulfide bridge at the hinge region; (iii) an Fd fragment consisting of a VH and CH1 domain; (iv) an Fv fragment consisting of the VL and VH domains of a single-arm antibody; (v) a dAb fragment consisting of a VH domain (see Ward et al., Nature. 341: 544-546 (1989)); and (vi) a nanobody, an antibody comprising a single variable domain and two constant domains. In addition, although the two domains VL and VH of the Fv fragment are encoded by different genes, VH and VL can be connected into a single protein chain by a recombinant method through a linker, wherein VL and VH are paired to form a monovalent molecule called single-chain Fv (scFv) (see Bird et al., Science. 242: 423-426 (1988); Huston et al., Proc. Natl. Acad. Sci. 85: 5879-5883 (1988)), and these single-chain antibodies are also encompassed by the term antigen-binding fragment. These antibody fragments can be obtained by conventional techniques known to those skilled in the art, and the fragments can be functionally screened by the same method as full-length antibodies.

[0070] The term "identity" is also known as consistency. The "percentage (%) identity" of an amino acid sequence refers to the percentage of amino acid residues in the sequence to be aligned that are identical to the amino acid residues in the specific amino acid sequence shown in this article, after comparing the sequence to be aligned and, if necessary, introducing gaps to achieve maximum sequence identity, and not considering any conservative substitutions as part of sequence identity. The alignment of amino acid sequences for identity can be performed in a variety of ways within the scope of the art, such as BLAST, BLAST-2, ALIGN or Megalign (DNASTAR) software. Those skilled in the art can determine the appropriate parameters for aligning sequences, including any algorithm needed to obtain maximum alignment over the full length of the comparison sequence.

[0071] The term "treating" means administering a compound of the present disclosure to prevent, ameliorate, or eliminate a disease or one or more symptoms associated with the disease, and includes but is not limited to:

[0072] (i) preventing a disease or disease state from occurring in a mammal, particularly where such mammal is susceptible to the disease state but has not yet been diagnosed as having the disease state;

[0073] (ii) inhibiting the disease or disease state, i.e., curbing its development;

[0074] (iii) alleviate the disease or condition, even if the disease or condition regresses;

[0075] (iv) reducing any direct or indirect pathological consequences of the disease or disease state.

[0076] The term "therapeutically effective amount" means an amount of a compound of the present disclosure that (i) treats or prevents a specific disease, condition, or disorder, (ii) alleviates, ameliorates, or eliminates one or more symptoms of a specific disease, condition, or disorder, or (iii) prevents or delays the onset of one or more symptoms of a specific disease, condition, or disorder described herein. The amount of a compound of the present disclosure that constitutes a "therapeutically effective amount" may vary depending on factors such as the compound and its ability to elicit a desired response in a subject, the disease state and its severity, the route of administration, and the age, sex, and weight of the mammal to be treated.

[0077] The terms "administering" or "administering" refer to the physical introduction of a therapeutic agent into a subject using any of a variety of methods and delivery systems known to those skilled in the art.

[0078] The route of administration of antibody drug conjugates (such as anti-HER2 antibody drug conjugates) includes intravenous, intramuscular, intraperitoneal, spinal column or other parenteral administration routes.Term used herein " parenteral administration " refers to, the mode of administration of the non-enteral administration carried out by injection usually, and includes but is not limited to, intravenous, intramuscular, intraarterial, intrathecal, intralymphatic, intralesional, intracapsular, intraorbital, intracardiac, intradermal, intraperitoneal, transtracheal, subcutaneous, subcutaneous, intraarticular, subcapsular, subarachnoid, spinal column, epidural and intrasternal injection and infusion and in vivo electroporation.Administration can also be performed, for example, once, repeatedly, and / or in one or more extended time periods.

[0079] The term "pharmaceutically acceptable" refers to those compounds, materials, compositions and / or dosage forms that are, within the scope of sound medical judgment, suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response or other problems or complications, commensurate with a reasonable benefit / risk ratio.

[0080] The term "pharmaceutically acceptable salt" refers to a salt of a compound (e.g., the antibody-drug conjugates of the present disclosure) that is safe and effective when used in mammals and has the desired biological activity. For example, the salt may be a metal salt, an ammonium salt, a salt formed with an organic base, a salt formed with an inorganic acid, a salt formed with an organic acid, a salt formed with a basic or acidic amino acid, etc.

[0081] The term "excipient" refers to any ingredient other than the active ingredient (e.g., the antibody drug conjugate of the present disclosure). The choice of excipient will largely depend on factors such as the specific mode of administration, the effect of the excipient on solubility and stability, and the nature of the dosage form.

[0082] The term "solvate" refers to an association of a compound with solvent molecules.

[0083] In the present disclosure, "HER2-positive" colorectal cancer is not particularly limited as long as it is a colorectal cancer recognized by those skilled in the art as overexpressing HER2. Preferably, for example, it is a colorectal cancer whose HER2 expression is determined to be 3+ by immunohistochemistry (IHC) (i.e., HER2 detection by IHC is determined to be IHC 3+), or / and a colorectal cancer whose HER2 expression is determined to be 2+ by IHC and whose HER2 expression is positive by in situ hybridization (ISH) (i.e., HER2 detection by IHC is determined to be IHC 2+ and HER2 detection by ISH is determined to be ISH+). It should be noted that the in situ hybridization method disclosed in the present disclosure includes, but is not limited to, fluorescence in situ hybridization (FISH) or dual-color in situ hybridization (DISH).

[0084] As used herein, the terms "subject," "patient," or "subject" are used interchangeably. "Subject," "patient," or "subject" includes any human or non-human animal. The term "non-human animal" includes, but is not limited to, vertebrates such as non-human primates, sheep, dogs, and rodents such as mice, rats, and guinea pigs. In some embodiments, the subject, patient, or subject is a mammal. In some embodiments, the subject, patient, or subject is a mouse. In some embodiments, the subject, patient, or subject is a human.

[0085] The term "pharmaceutical composition" refers to a mixture of one or more active ingredients (e.g., the anti-HER2 antibody drug conjugates of the present disclosure) and pharmaceutically acceptable excipients. The purpose of a pharmaceutical composition is to facilitate administration of the active ingredients to a subject. As used herein, the terms "pharmaceutical composition" and "preparation" have the same meaning and are used interchangeably.

[0086] The words “comprise,” “comprise,” or “comprises,” and variations thereof such as comprises or comprising, should be construed in an open, non-exclusive sense, ie, “including but not limited to.”

[0087] Herein, singular terms encompass plural referents and vice versa unless the context clearly dictates otherwise.

[0088] As used herein, "about" means within the acceptable error range for a particular value as determined by one of ordinary skill in the art, which depends in part on how the value is measured or determined, i.e., the limitations of the measurement system. For example, "about" can mean within 1 or more than 1 standard deviation as practiced in the art. Alternatively, "about" can mean a range of up to ±5%, such as fluctuations within ±2%, within ±1%, or within ±0.5% of the specific numerical range given. When a specific value is given in the present disclosure or claims, unless otherwise indicated, the meaning of "about" should be considered to be within the acceptable error range for that specific value. In this document, unless otherwise indicated, all values ​​for drug doses, times, step parameters, or conditions are modified by "about" by default.

[0089] For the purposes of description and disclosure, all patents, patent applications, and other identified publications are expressly incorporated herein by reference. These publications are provided solely because their disclosure predates the filing date of the present disclosure. All statements regarding the dates of these documents or representations of the contents of these documents are based on the information available to the applicant and do not constitute any admission as to the correctness of the dates of these documents or the contents of these documents. Furthermore, any citation of these publications herein does not constitute an admission that such publications are part of the common general knowledge in the art in any country.

[0090] The present disclosure also provides the following specific implementation schemes, but the protection scope of the present disclosure is not limited thereto:

[0091] Embodiment 1. A method for treating colorectal cancer in a subject, comprising administering to the subject an anti-HER2 antibody drug conjugate, wherein the anti-HER2 antibody drug conjugate is represented by the following formula Ia

[0092] The drug-linker of the structure shown is connected to the antigen-binding construct targeting HER2.

[0093] The 3-position of -(succinimide-3-yl-N)- in Formula Ia is linked to an antigen-binding construct targeting HER2,

[0094] The HER2-targeting antigen-binding construct comprises a first antigen-binding fragment and a second antigen-binding fragment, wherein the first antigen-binding fragment comprises: a HCDR1 comprising the amino acid sequence of SEQ ID NO: 1, a HCDR2 comprising the amino acid sequence of SEQ ID NO: 2, a HCDR3 comprising the amino acid sequence of SEQ ID NO: 3, a LCDR1 comprising the amino acid sequence of SEQ ID NO: 4, a LCDR2 comprising the amino acid sequence of SEQ ID NO: 5, and a LCDR3 comprising the amino acid sequence of SEQ ID NO: 6, and the second antigen-binding fragment comprises: a HCDR1 comprising the amino acid sequence of SEQ ID NO: 9, a HCDR2 comprising the amino acid sequence of SEQ ID NO: 10, a HCDR3 comprising the amino acid sequence of SEQ ID NO: 11, a LCDR1 comprising the amino acid sequence of SEQ ID NO: 12, a LCDR2 comprising the amino acid sequence of SEQ ID NO: 13, and a LCDR3 comprising the amino acid sequence of SEQ ID NO: 14.

[0095] Embodiment 2. The method according to embodiment 1, wherein the average number of drug-linker connections per HER2-targeting antigen-binding construct is 4 to 7.

[0096] Embodiment 3. The method according to embodiment 2, wherein the average number of drug-linker connections per HER2-targeting antigen-binding construct is 5 to 6.

[0097] Embodiment 4. The method according to embodiment 3, wherein the average number of drug-linker connections per HER2-targeting antigen-binding construct is 5.5 to 6.

[0098] Embodiment 5. The method according to any one of embodiments 1-4, wherein

[0099] (i) the first antigen-binding fragment comprises a heavy chain variable region whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO:7;

[0100] (ii) the first antigen-binding fragment comprises a light chain variable region whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO:8;

[0101] (iii) the first antigen-binding fragment comprises a heavy chain variable region whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:7, and a light chain variable region whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:8;

[0102] (iv) the second antigen-binding fragment comprises a heavy chain variable region whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 15;

[0103] (v) the second antigen-binding fragment comprises a light chain variable region whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 16;

[0104] (vi) the second antigen-binding fragment comprises a heavy chain variable region that has an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:15, and a light chain variable region that has an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:16; or

[0105] (vii) the first antigen-binding fragment comprises a heavy chain variable region whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:7, and a light chain variable region whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:8; and the second antigen-binding fragment comprises an amino acid sequence identical to SEQ ID NO: NO:15 has a heavy chain variable region that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO:15, and a light chain variable region that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO:16.

[0106] Embodiment 6. The method according to any one of embodiments 1-5, wherein

[0107] (i) the antigen-binding construct targeting HER2 comprises a first polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 17 or 20;

[0108] (ii) the antigen-binding construct targeting HER2 comprises a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 18 or 21;

[0109] (iii) the antigen-binding construct targeting HER2 comprises a third polypeptide chain having an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 19;

[0110] (iv) the antigen-binding construct targeting HER2 comprises a first polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 17 or 20, a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 18 or 21, and a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: a third polypeptide chain having at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identity to the amino acid sequence of NO:19;

[0111] (v) the antigen-binding construct targeting HER2 comprises a first polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 17, a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 18, and a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: a third polypeptide chain having at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identity to the amino acid sequence of NO:19;

[0112] (vi) the antigen-binding construct targeting HER2 comprises a first polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 20, a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 21, and a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: a third polypeptide chain having at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identity to the amino acid sequence of NO:19;

[0113] (vii) the antigen-binding construct targeting HER2 comprises a first polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 17, a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 21, and a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: a third polypeptide chain that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of NO:19; or

[0114] (viii) the antigen-binding construct targeting HER2 comprises a first polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 20, a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 18, and a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: The invention also provides a method for preparing a polypeptide chain having at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identity with the amino acid sequence shown in NO:19.

[0115] Embodiment 7. The method of any one of Embodiments 1-6, wherein the anti-HER2 antibody drug conjugate is administered in a therapeutically effective amount.

[0116] Embodiment 8. The method according to any one of embodiments 1-6, wherein the anti-HER2 antibody drug conjugate is administered at a dose of 1.5-9 mg / kg, 4.5-7.5 mg / kg, or 6-7.5 mg / kg each time; preferably, the anti-HER2 antibody drug conjugate is administered at a dose of 6-7.5 mg / kg each time.

[0117] Embodiment 9. The method according to embodiment 8, wherein the anti-HER2 antibody drug conjugate is administered at a dose of 1.5 mg / kg, 3 mg / kg, 4.5 mg / kg, 5 mg / kg, 6 mg / kg, 7.5 mg / kg or 9 mg / kg each time; preferably, the anti-HER2 antibody drug conjugate is administered at a dose of 6 mg / kg or 7.5 mg / kg each time.

[0118] Embodiment 10. The method according to any one of embodiments 1-9, wherein the anti-HER2 antibody drug conjugate is administered once every 1 week, every 2 weeks, every 3 weeks, or every 4 weeks; preferably, the anti-HER2 antibody drug conjugate is administered once every 3 weeks.

[0119] Embodiment 11. The method according to any one of embodiments 1-10, wherein the anti-HER2 antibody drug conjugate is formulated as a preparation for intravenous injection or infusion.

[0120] Embodiment 12. The method of any one of Embodiments 1-11, wherein the anti-HER2 antibody drug conjugate is administered by intravenous infusion.

[0121] Embodiment 13. The method according to any one of embodiments 1-12, wherein the intestinal cancer is locally advanced intestinal cancer.

[0122] Embodiment 14. The method according to any one of Embodiments 1-12, wherein the intestinal cancer is intestinal cancer with distant metastasis.

[0123] Embodiment 15. The method according to any one of embodiments 1-14, wherein the intestinal cancer is unresectable intestinal cancer.

[0124] Embodiment 16. The method according to any one of embodiments 1-15, wherein the colorectal cancer is HER2-expressing colorectal cancer.

[0125] Embodiment 17. The method according to any one of Embodiments 1-16, wherein the colorectal cancer is HER2-positive colorectal cancer.

[0126] Embodiment 18. The method according to Embodiment 17, wherein the HER2-positive colorectal cancer is a colorectal cancer whose HER2 expression is determined to be 3+ by IHC.

[0127] Embodiment 19. The method according to Embodiment 17, wherein the HER2-positive colorectal cancer is a colorectal cancer in which the expression of HER2 is determined to be 2+ by IHC and the expression of HER2 is determined to be positive by ISH.

[0128] Embodiment 20. The method according to any one of embodiments 1-19, wherein the subject with colorectal cancer has previously received at least two lines of treatment for colorectal cancer.

[0129] Embodiment 21. The method according to any one of embodiments 1-20, wherein the subject with bowel cancer has previously received chemotherapy to treat bowel cancer.

[0130] Embodiment 22. A method according to any one of embodiments 1-21, wherein the subject with colorectal cancer has previously received standard treatment for colorectal cancer.

[0131] Embodiment 23. The method of embodiment 22, wherein the standard of care comprises administering fluorouracil or a derivative thereof, oxaliplatin, and / or irinotecan to the subject.

[0132] Embodiment 24. The method according to any one of embodiments 1-23, wherein the subject with colorectal cancer has previously received adjuvant therapy for colorectal cancer.

[0133] Embodiment 25. The method of embodiment 24, wherein the adjunctive therapy comprises administering oxaliplatin to the subject.

[0134] Embodiment 26. The method according to any one of embodiments 1-25, wherein the subject with intestinal cancer has previously received local radiotherapy to treat intestinal cancer.

[0135] Embodiment 27. The method according to any one of embodiments 1-26, wherein the intestinal cancer is colon cancer, rectal cancer or colorectal cancer.

[0136] Embodiment 28. Use of an anti-HER2 antibody drug conjugate in the preparation of a medicament for treating colorectal cancer in a subject, wherein the anti-HER2 antibody drug conjugate is represented by the following formula Ia

[0137] The drug-linker of the structure shown is connected to the antigen-binding construct targeting HER2.

[0138] The 3-position of -(succinimide-3-yl-N)- in Formula Ia is linked to an antigen-binding construct targeting HER2,

[0139] The HER2-targeting antigen-binding construct comprises a first antigen-binding fragment and a second antigen-binding fragment, wherein the first antigen-binding fragment comprises: a HCDR1 comprising the amino acid sequence of SEQ ID NO: 1, a HCDR2 comprising the amino acid sequence of SEQ ID NO: 2, a HCDR3 comprising the amino acid sequence of SEQ ID NO: 3, a LCDR1 comprising the amino acid sequence of SEQ ID NO: 4, a LCDR2 comprising the amino acid sequence of SEQ ID NO: 5, and a LCDR3 comprising the amino acid sequence of SEQ ID NO: 6, and the second antigen-binding fragment comprises: a HCDR1 comprising the amino acid sequence of SEQ ID NO: 9, a HCDR2 comprising the amino acid sequence of SEQ ID NO: 10, a HCDR3 comprising the amino acid sequence of SEQ ID NO: 11, a LCDR1 comprising the amino acid sequence of SEQ ID NO: 12, a LCDR2 comprising the amino acid sequence of SEQ ID NO: 13, and a LCDR3 comprising the amino acid sequence of SEQ ID NO: 14.

[0140] Embodiment 29. The use according to embodiment 28, wherein the average number of drug-linker connections per HER2-targeting antigen-binding construct is 4 to 7.

[0141] Embodiment 30. The use according to embodiment 29, wherein the average number of drug-linker connections per HER2-targeting antigen-binding construct is 5 to 6.

[0142] Embodiment 31. The use according to embodiment 30, wherein the average number of drug-linker connections per HER2-targeting antigen-binding construct is 5.5 to 6.

[0143] Embodiment 32. The use according to any one of embodiments 28-31, wherein

[0144] (i) the first antigen-binding fragment comprises a heavy chain variable region whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO:7;

[0145] (ii) the first antigen-binding fragment comprises a light chain variable region whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO:8;

[0146] (iii) the first antigen-binding fragment comprises a heavy chain variable region whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:7, and a light chain variable region whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:8;

[0147] (iv) the second antigen-binding fragment comprises a heavy chain variable region whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 15;

[0148] (v) the second antigen-binding fragment comprises a light chain variable region whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 16;

[0149] (vi) the second antigen-binding fragment comprises a heavy chain variable region that has an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:15, and a light chain variable region that has an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:16; or

[0150] (vii) the first antigen-binding fragment comprises a heavy chain variable region whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:7, and a light chain variable region whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:8; and the second antigen-binding fragment comprises an amino acid sequence identical to SEQ ID NO: NO:15 has a heavy chain variable region that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO:15, and a light chain variable region that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO:16.

[0151] Embodiment 33. The use according to any one of embodiments 28-32, wherein

[0152] (i) the antigen-binding construct targeting HER2 comprises a first polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 17 or 20;

[0153] (ii) the antigen-binding construct targeting HER2 comprises a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 18 or 21;

[0154] (iii) the antigen-binding construct targeting HER2 comprises a third polypeptide chain having an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 19;

[0155] (iv) the antigen-binding construct targeting HER2 comprises a first polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 17 or 20, a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 18 or 21, and a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: a third polypeptide chain having at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identity to the amino acid sequence of NO:19;

[0156] (v) the antigen-binding construct targeting HER2 comprises a first polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 17, a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 18, and a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: a third polypeptide chain having at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identity to the amino acid sequence of NO:19;

[0157] (vi) the antigen-binding construct targeting HER2 comprises a first polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 20, a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 21, and a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: a third polypeptide chain having at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identity to the amino acid sequence of NO:19;

[0158] (vii) the antigen-binding construct targeting HER2 comprises a first polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 17, a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 21, and a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: a third polypeptide chain that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of NO:19; or

[0159] (viii) the antigen-binding construct targeting HER2 comprises a first polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 20, a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 18, and a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: The invention also provides a method for preparing a polypeptide chain having at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identity with the amino acid sequence shown in NO:19.

[0160] Embodiment 34. The use according to any one of Embodiments 28-33, wherein the medicament comprises a therapeutically effective amount of the anti-HER2 antibody drug conjugate.

[0161] Embodiment 35. The use according to any one of embodiments 28-33, wherein the anti-HER2 antibody drug conjugate is administered at a dose of 1.5-9 mg / kg, 4.5-7.5 mg / kg, or 6-7.5 mg / kg each time; preferably, the anti-HER2 antibody drug conjugate is administered at a dose of 6-7.5 mg / kg each time.

[0162] Embodiment 36. The use according to embodiment 35, wherein the anti-HER2 antibody drug conjugate is administered at a dose of 1.5 mg / kg, 3 mg / kg, 4.5 mg / kg, 5 mg / kg, 6 mg / kg, 7.5 mg / kg or 9 mg / kg each time; preferably, the anti-HER2 antibody drug conjugate is administered at a dose of 6 mg / kg or 7.5 mg / kg each time.

[0163] Embodiment 37. The use according to any one of embodiments 28-36, wherein the anti-HER2 antibody drug conjugate is administered once every 1 week, every 2 weeks, every 3 weeks, or every 4 weeks; preferably, the anti-HER2 antibody drug conjugate is administered once every 3 weeks.

[0164] Embodiment 38. The use according to any one of Embodiments 28-37, wherein the anti-HER2 antibody drug conjugate is formulated as a preparation for intravenous injection or infusion.

[0165] Embodiment 39. The use according to any one of embodiments 28-38, wherein the anti-HER2 antibody drug conjugate is administered by intravenous infusion.

[0166] Embodiment 40. The use according to any one of embodiments 28-39, wherein the intestinal cancer is locally advanced intestinal cancer.

[0167] Embodiment 41. The use according to any one of Embodiments 28-39, wherein the intestinal cancer is intestinal cancer with distant metastasis.

[0168] Embodiment 42. The use according to any one of embodiments 28-41, wherein the intestinal cancer is unresectable intestinal cancer.

[0169] Embodiment 43. The use according to any one of Embodiments 28-42, wherein the intestinal cancer is HER2-expressing intestinal cancer.

[0170] Embodiment 44. The use according to any one of Embodiments 28-43, wherein the colorectal cancer is HER2-positive colorectal cancer.

[0171] Embodiment 45. The use according to Embodiment 44, wherein the HER2-positive colorectal cancer is a colorectal cancer whose HER2 expression is determined to be 3+ by IHC.

[0172] Embodiment 46. The use according to embodiment 44, wherein the HER2-positive colorectal cancer is a colorectal cancer in which the expression of HER2 is determined to be 2+ by IHC and the expression of HER2 is determined to be positive by ISH.

[0173] Embodiment 47. The use according to any one of Embodiments 28-46, wherein the subject with intestinal cancer has previously received at least two lines of treatment for intestinal cancer.

[0174] Embodiment 48. The use according to any one of embodiments 28-47, wherein the subject with bowel cancer has previously received chemotherapy to treat bowel cancer.

[0175] Embodiment 49. The use according to any one of embodiments 28-48, wherein the subject with intestinal cancer has previously received standard treatment for intestinal cancer.

[0176] Embodiment 50. The use according to embodiment 49, wherein the standard treatment comprises administering fluorouracil or a derivative thereof, oxaliplatin and / or irinotecan to the subject.

[0177] Embodiment 51. The use according to any one of embodiments 28-50, wherein the subject with intestinal cancer has previously received adjuvant therapy for the treatment of intestinal cancer.

[0178] Embodiment 52. The use according to embodiment 51, wherein the adjunctive therapy comprises administering oxaliplatin to the subject.

[0179] Embodiment 53. The use according to any one of embodiments 28-52, wherein the subject with intestinal cancer has previously received local radiotherapy to treat intestinal cancer.

[0180] Embodiment 54. The use according to any one of embodiments 28-53, wherein the intestinal cancer is colon cancer, rectal cancer or colorectal cancer. BRIEF DESCRIPTION OF THE DRAWINGS

[0181] Figure 1 is a growth curve of tumor volume in tumor-bearing mice in the vehicle control group, ADC1 (3 mg / kg) administration group, ADC1 (10 mg / kg) administration group, and DS-8201a (10 mg / kg) administration group in the COLO-205 tumor model. Example

[0182] For the purpose of clarity, the present disclosure is further illustrated with examples, but the examples do not limit the scope of the present disclosure.

[0183] The entire contents of WO2022033578 or CN115702008A patent application documents are incorporated herein by reference. The anti-HER2 antibody drug conjugates in the following examples are prepared with reference to the preparation method described in WO2022033578 and are represented by the following formula (hereinafter referred to as ADC1):

[0184] The drug-linker is connected to the HER2-targeting antigen-binding construct via a thioether bond, and n is 5 to 6. Briefly, the nucleic acid sequences encoding the three polypeptide chains of the HER2-targeting antigen-binding construct (amino acid sequences are shown in SEQ ID NOs: 17, 18, and 19, respectively) are cloned into the pcDNA3.1 expression vector, co-transfected into FUT8-knockout CHO-S cells for expression, and purified by protein A to prepare the HER2-targeting antigen-binding construct. The HER2-targeting antigen-binding construct is treated with tris(2-carboxyethyl)phosphine hydrochloride and then reacted with a linker-payload selected from the structure shown in the following formula to ultimately obtain ADC1:

[0185] Example 1: Anti-tumor effect of anti-HER2 antibody drug conjugate in COLO-205 mouse tumor model

[0186] BALB / c Nude mice (from Jicui Yaokang) were subcutaneously inoculated with COLO-205 (source: Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences) human colon cancer cells on the right back. The cell inoculation volume was 5×10 6 When the average tumor volume in vivo grows to 100mm 3 Around 24 hours after the start of treatment, mice were randomly divided into four groups of six mice each. The day of grouping was defined as Day 0. Starting from Day 0, the drug was administered intravenously according to the schedule in Table 2. DS-8201a (trastuzumab) from Daiichi Sankyo was used as a positive control, and 5% glucose solution was used as a vehicle control. After the start of treatment, the body weight and tumor size of the mice were measured twice a week, and the tumor growth inhibition rate (TGI) was calculated.

[0187] Tumor volume (mm 3 ) = 0.5 × (long diameter of tumor × short diameter of tumor 2 );

[0188] TGI (%) = (1-T / C) × 100%;

[0189] T / C=T RTV / CRTV × 100%, where T RTV is the average relative tumor volume (RTV) of the treatment group, C RTV is the average RTV of the vehicle control group; RTV = V t / V0, V0 is the tumor volume of the animal when grouped, V t is the tumor volume of the animal after drug administration.

[0190] Table 2. Dosage regimen

[0191] The results are shown in Table 3 and Figure 1 , where ADC1 has better anti-tumor activity than DS-8201a. This shows that the anti-HER2 antibody drug conjugate disclosed in the present invention has good anti-tumor activity in animals with colon cancer.

[0192] Table 3. Anti-tumor effects of anti-HER2 antibody drug conjugates in the COLO-205 mouse tumor model

[0193] Example 2: Phase I clinical trial of HER2-expressing malignant tumors

[0194] 1. Research objectives:

[0195] 1.1 Main Purpose:

[0196] To evaluate the tolerability of ADC1 in subjects with advanced malignancies.

[0197] 1.2 Secondary Purpose:

[0198] To evaluate the pharmacokinetic (PK), immunogenicity, safety, and preliminary efficacy of ADC1 in subjects with advanced malignancies;

[0199] To evaluate potential biomarkers related to the mechanism of action of ADC1 in subjects with advanced malignancies.

[0200] 2. Selection Criteria

[0201] Only those who meet all of the following inclusion criteria can be enrolled in this trial:

[0202] (1) The subjects voluntarily participated in this study and signed the informed consent form;

[0203] (2) Age: 18-75 years old (at the time of signing the informed consent); ECOG score: ≤1; expected survival time: more than 3 months;

[0204] (3) Dose escalation phase: subjects with advanced malignancies (including HER2-positive colorectal cancer) confirmed by cytology / histopathology, with priority given to subjects with HER2 expression, amplification, or mutation;

[0205] Extension study phase: patients with unresectable locally advanced or distant metastatic colorectal cancer who are required to be HER2-positive by pathological examination (HER2 3+ by immunohistochemistry, or HER2 2+ and ISH-positive);

[0206] (4) Subjects with malignant tumors who have failed standard treatment or lack effective treatment (including failure of 1st-line treatment, 2nd-line treatment, 3rd-line treatment and more lines of treatment, such as failure of previous anti-HER2 ADC, trastuzumab, pertuzumab, pyrotinib, lapatinib, regorafenib, fruquintinib, bevacizumab, and cetuximab treatment); the specific requirements of the expansion cohort are as follows:

[0207] Colorectal cancer requires patients to have received ≥2 lines of standard chemotherapy in the past, and to have experienced disease progression or intolerance during standard treatment or within 3 months of the last treatment. Standard treatment regimens must include fluorouracil or its derivatives, oxaliplatin, irinotecan, etc.; patients who use oxaliplatin in adjuvant treatment should have disease progression during adjuvant treatment or within 6 months after the completion of adjuvant treatment; intolerance refers to hematological toxicity reaching grade IV (thrombocytopenia grade III or above) and non-hematological toxicity reaching grade III or above;

[0208] (5) In the dose escalation phase, at least one evaluable lesion must be confirmed according to the RECIST 1.1 standard (measurable is not required, as long as the disease status can be assessed); in the cohort expansion phase, at least one measurable lesion must be confirmed according to the RECIST 1.1 standard;

[0209] (6) The main organs are functioning well and meet the standards of blood routine examination, biochemical examination, coagulation function examination, and cardiac ultrasound assessment:

[0210] (7) Female subjects of childbearing age should agree to use contraceptive measures (such as intrauterine devices, birth control pills or condoms) during the study and within 6 months after the end of the study; the serum pregnancy test should be negative within 7 days before enrollment in the study, and the subjects must be non-breastfeeding; male subjects should agree to use contraceptive measures during the study and within 6 months after the end of the study.

[0211] 3. Trial Drugs

[0212] ADC1 for injection (specification: 100 mg / bottle) is developed and provided by Nanjing Shunxin Pharmaceutical Co., Ltd. of Zhengda Tianqing Pharmaceutical Group.

[0213] 4. Treatment options

[0214] 4.1 Dose escalation phase:

[0215] Six dose groups were used for dose escalation, with the dose group levels being: 1.5 mg / kg, 3 mg / kg, 4.5 mg / kg, 6 mg / kg, 7.5 mg / kg and 9 mg / kg; one treatment cycle was every 3 weeks (21 days), and ADC1 was administered once in each treatment cycle until the disease progressed or the researcher determined that it was not suitable for continued medication.

[0216] 4.2 Extended research phase:

[0217] In the dose-escalation phase, 1-2 appropriate dose groups (including 6 mg / kg and 7.5 mg / kg) were selected, with one treatment cycle consisting of 3 weeks (21 days), and ADC1 was administered once per treatment cycle until the disease progressed or the researcher determined that the drug was not suitable for continued use.

[0218] Adjustments may be made based on disease severity, disease response, any treatment-related toxicities, and the patient's age and health status.

[0219] 5. Evaluation Criteria

[0220] Effectiveness evaluation: RECIST 1.1 criteria were used to determine the disease status.

[0221] Safety evaluation: The NCI-CTC AE 5.0 standard was used to judge the severity of adverse events.

[0222] 6. Endpoint indicators

[0223] 6.1 Primary Endpoint:

[0224] Dose-limiting toxicity (DLT), maximum tolerated dose (MTD), and recommended phase 2 dose (RP2D);

[0225] the incidence and severity of adverse events (AEs);

[0226] 6.2 Secondary End Points:

[0227] immunogenicity (e.g., ADA incidence);

[0228] Pharmacokinetic parameters;

[0229] Objective response rate (ORR), disease control rate (DCR), duration of response (DOR), progression-free survival (PFS), and overall survival (OS).

[0230] 7. Results

[0231] As of the clinical data collection date, a total of 24 patients with stage IV colorectal cancer (including those with primary lesions in the rectum, sigmoid colon, and colon) enrolled in the 7.5 mg / kg dose group were evaluable, with an ORR of approximately 29% (7 / 24) and a DCR of 87.5% (21 / 24). In particular, better effects were observed in HER2-positive patients with IHC 3+ (20 patients in total) (ORR reaching 35%). In the above-mentioned dose group, the median time to response for ADC1 treatment reached 2.66 months, the median progression-free survival (mPFS) reached 6.7 months (95% CI), and the incidence of interstitial lung disease was 0. Among these 24 evaluable patients, 66.6% (16 / 24) had previously received anti-HER2 treatment, including 5 patients who had previously received anti-HER2 ADCs.

[0232] The anti-HER2 antibody-drug conjugate disclosed herein can show good therapeutic efficacy and safety in patients with HER2-positive intestinal cancer, especially colorectal cancer.

[0233] Example 3: Phase III clinical trial of HER2 IHC 3+ advanced colorectal cancer

[0234] 1. Research objectives:

[0235] 1.1 Main Purpose:

[0236] Methods: ADC1 was compared with standard of care (trifluridine tipiracil tablets) in patients with HER2 IHC 3+ advanced colorectal cancer who had previously been treated with oxaliplatin, 5-fluorouracil, and irinotecan, as measured by progression-free survival (PFS) assessed by an independent review committee (IRC).

[0237] 1.2 Key secondary objectives:

[0238] The efficacy of ADC1 was compared with standard treatment (trifluridine tipiracil tablets) by overall survival (OS).

[0239] 1.3 Secondary Purpose

[0240] The efficacy of ADC1 was compared with standard treatment (trifluridine tipiracil tablets) by investigator-assessed PFS, ORR, DCR, DOR, and time to response (TTR);

[0241] To evaluate the safety and tolerability of ADC1 compared with standard of care (trifluridine tipiracil tablets).

[0242] 2. Selection Criteria

[0243] Only those who meet all of the following inclusion criteria can be enrolled in this trial:

[0244] (1) The subjects voluntarily participated in this study, signed the informed consent form, and had good compliance;

[0245] (2) Age: 18 years old ≤ ≤ 75 years old (calculated based on the date of signing the informed consent form);

[0246] (3) subjects with advanced colorectal cancer confirmed by histology or cytology;

[0247] (4) The subject had confirmed HER2 IHC 3+ in tumor tissue;

[0248] (5) The subject must be able to provide sufficient qualified tumor specimens (fresh or archived samples of primary or metastatic lesions collected within 3 years) for HER2 status testing in the central laboratory;

[0249] (6) Failure of at least 2 lines of standard treatment (defined as disease progression or toxicity during the last standard treatment or within 3 months after the last treatment)

[0250] Advanced colorectal cancer with sexual intolerance:

[0251] ● Previous failure of oxaliplatin, irinotecan, or 5-fluorouracil (patients with known dMMR / MSI-H also need to have failed anti-PD-1 / PD-L1 antibody therapy);

[0252] ●If the subject received oxaliplatin, irinotecan, or 5-fluorouracil as initial systemic treatment, it was counted as second-line systemic treatment;

[0253] If the subject relapses within 6 months of the last adjuvant therapy, adjuvant therapy will be counted as first-line systemic therapy.

[0254] ● Subjects are eligible for trifluridine tipiracil tablets as standard treatment after randomization, and previous treatment with small molecule inhibitors targeting VEGFR, such as regorafenib or fruquintinib, is permitted;

[0255] ● Previous treatment toxicity intolerance is defined as the occurrence of grade 3 or higher AEs that, despite symptomatic supportive care, led to treatment discontinuation or the subject's voluntary request to discontinue treatment due to intolerance;

[0256] (7) ECOG score 0–1;

[0257] (8) expected survival greater than 12 weeks;

[0258] (9) Confirmed to have at least one measurable lesion according to RECIST 1.1 criteria;

[0259] (10) Meet the standards of blood routine test, biochemical test, urine routine test, coagulation function test, thyroid stimulating hormone test, and be in the electrolyte

[0260] equilibrium state;

[0261] (11) Women of childbearing age should agree to use effective contraceptive measures during the study and within 6 months after the end of the study, and have a negative serum or urine pregnancy test within 7 days before study enrollment; men should agree to use effective contraceptive measures during the study and within 6 months after the end of the study.

[0262] 3. Trial Drugs

[0263] ADC1 for injection (specification: 100 mg / bottle) is developed and provided by Nanjing Shunxin Pharmaceutical Co., Ltd. of Zhengda Tianqing Pharmaceutical Group.

[0264] ADC1 placebo for injection was provided by Nanjing Shunxin Pharmaceutical Co., Ltd. of Zhengda Tianqing Pharmaceutical Group.

[0265] Trifluridine tipiracil tablets (specifications: 15 mg / tablet or 20 mg / tablet) are provided by Nanjing Shunxin Pharmaceutical Co., Ltd. of Zhengda Tianqing Pharmaceutical Group.

[0266] Trifluridine-tipivirine placebo was provided by Nanjing Shunxin Pharmaceutical Co., Ltd. of Zhengda Tianqing Pharmaceutical Group.

[0267] 4. Trial Design and Treatment Plan

[0268] Subjects who met the inclusion criteria were randomly assigned to the experimental group or the control group in a 1:1 ratio.

[0269] 4.1 Grouping

[0270] Experimental group: ADC1, 7.5 mg / kg, intravenous drip, administered on the first day of each treatment cycle, with one treatment cycle consisting of three weeks; trifluridine tipiracil placebo, administered orally twice a day on days 1-5 and days 8-12, with one treatment cycle consisting of four weeks.

[0271] Control group: trifluridine tipiracil tablets, 35 mg / m 2 / time (maximum single dose is 80 mg), orally administered twice daily on days 1-5 and days 8-12, with one treatment cycle of 4 weeks; ADC1 placebo, intravenous drip, administered on the first day of each treatment cycle, with one treatment cycle of 3 weeks.

[0272] Adjustments may be made based on disease severity, disease response, any treatment-related toxicities, and the patient's age and health status.

[0273] 5. Evaluation Criteria

[0274] Effectiveness evaluation: RECIST 1.1 criteria were used to determine the disease status.

[0275] Safety evaluation: Safety assessment variables include physical examination, vital signs, 12-lead electrocardiogram, laboratory tests, specialist examinations and all AEs (including SAEs).

[0276] 6. Endpoint indicators

[0277] 6.1 Primary Endpoint:

[0278] IRC-assessed PFS;

[0279] 6.2 Key Secondary Endpoints:

[0280] OS;

[0281] 6.3 Other secondary endpoints:

[0282] Investigator-assessed PFS, ORR, DOR, DCR, TTR, and safety.

[0283] After administration of the anti-HER2 antibody drug conjugates of the present disclosure, colorectal cancer patients can expect to obtain clinical benefits, including expected efficacy and safety.

Claims

1. An anti-HER2 antibody drug conjugate for treating colorectal cancer in a subject, wherein: The anti-HER2 antibody drug conjugate is represented by the following formula Ia The drug-linker of the structure shown is connected to the antigen-binding construct targeting HER2. The 3-position of -(succinimide-3-yl-N)- in Formula Ia is linked to an antigen-binding construct targeting HER2, The HER2-targeting antigen-binding construct comprises a first antigen-binding fragment and a second antigen-binding fragment, wherein the first antigen-binding fragment comprises: a HCDR1 comprising the amino acid sequence of SEQ ID NO: 1, a HCDR2 comprising the amino acid sequence of SEQ ID NO: 2, a HCDR3 comprising the amino acid sequence of SEQ ID NO: 3, a LCDR1 comprising the amino acid sequence of SEQ ID NO: 4, a LCDR2 comprising the amino acid sequence of SEQ ID NO: 5, and a LCDR3 comprising the amino acid sequence of SEQ ID NO: 6, and the second antigen-binding fragment comprises: a HCDR1 comprising the amino acid sequence of SEQ ID NO: 9, a HCDR2 comprising the amino acid sequence of SEQ ID NO: 10, a HCDR3 comprising the amino acid sequence of SEQ ID NO: 11, a LCDR1 comprising the amino acid sequence of SEQ ID NO: 12, a LCDR2 comprising the amino acid sequence of SEQ ID NO: 13, and a LCDR3 comprising the amino acid sequence of SEQ ID NO:

14.

2. The anti-HER2 antibody drug conjugate for treating colorectal cancer in a subject according to claim 1, wherein The average number of drug-linker connections per HER2-targeting antigen-binding construct is 4 to 7, 5 to 6, or 5.5 to 6.

3. The anti-HER2 antibody drug conjugate for treating colorectal cancer in a subject according to claim 1 or 2, wherein: (i) the first antigen-binding fragment comprises a heavy chain variable region whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO:7; (ii) the first antigen-binding fragment comprises a light chain variable region whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO:8; (iii) the first antigen-binding fragment comprises a heavy chain variable region whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:7, and a light chain variable region whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:8; (iv) the second antigen-binding fragment comprises a heavy chain variable region whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 15; (v) the second antigen-binding fragment comprises a light chain variable region whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 16; (vi) the second antigen-binding fragment comprises a heavy chain variable region that has an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:15, and a light chain variable region that has an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:16; or (vii) the first antigen-binding fragment comprises a heavy chain variable region whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:7, and a light chain variable region whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence of SEQ ID NO:8; and the second antigen-binding fragment comprises an amino acid sequence identical to SEQ ID NO: NO:15 has a heavy chain variable region that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO:15, and a light chain variable region that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO:

16.

4. The anti-HER2 antibody drug conjugate for treating colorectal cancer in a subject according to any one of claims 1 to 3, wherein: (i) the antigen-binding construct targeting HER2 comprises a first polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 17 or 20; (ii) the antigen-binding construct targeting HER2 comprises a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 18 or 21; (iii) the antigen-binding construct targeting HER2 comprises a third polypeptide chain having an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 19; (iv) the antigen-binding construct targeting HER2 comprises a first polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 17 or 20, a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 18 or 21, and a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: a third polypeptide chain having at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identity to the amino acid sequence of NO:19; (v) the antigen-binding construct targeting HER2 comprises a first polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 17, a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 18, and a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: a third polypeptide chain having at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identity to the amino acid sequence of NO:19; (vi) the antigen-binding construct targeting HER2 comprises a first polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 20, a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 21, and a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: a third polypeptide chain having at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identity to the amino acid sequence of NO:19; (vii) the antigen-binding construct targeting HER2 comprises a first polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 17, a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 21, and a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: a third polypeptide chain that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of NO:19; or (viii) the antigen-binding construct targeting HER2 comprises a first polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 20, a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 18, and a second polypeptide chain whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: The invention also provides a method for preparing a polypeptide chain having at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identity with the amino acid sequence shown in NO:

19.

5. The anti-HER2 antibody drug conjugate for treating colorectal cancer in a subject according to any one of claims 1 to 4, wherein: The anti-HER2 antibody drug conjugate is administered at a dose of 1.5-9 mg / kg, 4.5-7.5 mg / kg, or 6-7.5 mg / kg each time; preferably, the anti-HER2 antibody drug conjugate is administered at a dose of 6-7.5 mg / kg each time, or the anti-HER2 antibody drug conjugate is administered at a dose of 1.5 mg / kg, 3 mg / kg, 4.5 mg / kg, 5 mg / kg, 6 mg / kg, 7.5 mg / kg or 9 mg / kg each time.

6. The anti-HER2 antibody drug conjugate for treating colorectal cancer in a subject according to any one of claims 1 to 5, wherein: The anti-HER2 antibody drug conjugate is administered once every 1 week, every 2 weeks, every 3 weeks, or every 4 weeks; preferably, the anti-HER2 antibody drug conjugate is administered once every 3 weeks.

7. The anti-HER2 antibody drug conjugate for treating colorectal cancer in a subject according to any one of claims 1 to 6, wherein: The anti-HER2 antibody drug conjugate is formulated as a preparation for intravenous injection or infusion; preferably, the anti-HER2 antibody drug conjugate is administered by intravenous infusion.

8. The anti-HER2 antibody drug conjugate for treating colorectal cancer in a subject according to any one of claims 1 to 7, wherein: The intestinal cancer is locally advanced intestinal cancer or distant metastatic intestinal cancer.

9. The anti-HER2 antibody drug conjugate for treating colorectal cancer in a subject according to any one of claims 1 to 8, wherein: The intestinal cancer is unresectable intestinal cancer; The intestinal cancer is HER2-expressing intestinal cancer; and / or The colorectal cancer is HER2-positive colorectal cancer.

10. The anti-HER2 antibody drug conjugate for treating colorectal cancer in a subject according to claim 9, wherein The HER2-positive colorectal cancer is a colorectal cancer whose HER2 expression is 3+ as determined by IHC; or The HER2-positive colorectal cancer is a colorectal cancer in which the expression of HER2 is determined to be 2+ by IHC and the expression of HER2 is determined to be positive by ISH.

11. The anti-HER2 antibody drug conjugate for treating colorectal cancer in a subject according to any one of claims 1 to 10, wherein: The subject with colorectal cancer has previously received at least two lines of treatment for colorectal cancer: The subject with bowel cancer has previously received chemotherapy to treat bowel cancer: The subject with intestinal cancer has previously received standard treatment for intestinal cancer; The subject with colorectal cancer has previously received adjuvant therapy for colorectal cancer; and / or The subject with intestinal cancer has previously received local radiotherapy to treat intestinal cancer.

12. The anti-HER2 antibody drug conjugate for treating colorectal cancer in a subject according to claim 11, wherein The standard treatment comprises administering to the subject fluorouracil or its derivatives, oxaliplatin and / or irinotecan; or The adjuvant therapy comprises administering oxaliplatin to the subject.

13. The anti-HER2 antibody drug conjugate for treating colorectal cancer in a subject according to any one of claims 1 to 12, wherein: The subject is a colorectal cancer subject who has previously failed HER2 targeted drug treatment or VEGFR targeted drug treatment; preferably, the subject is a colorectal cancer subject who has previously failed one or more of anti-HER2 ADC, trastuzumab, pertuzumab, pyrotinib, lapatinib, regorafenib, fruquintinib, bevacizumab, and cetuximab.

14. The anti-HER2 antibody drug conjugate for treating colorectal cancer in a subject according to any one of claims 1 to 13, wherein: The intestinal cancer is sigmoid colon cancer, colon cancer, rectal cancer or colorectal cancer.

15. The anti-HER2 antibody drug conjugate for treating colorectal cancer in a subject according to any one of claims 1 to 14, wherein: The intestinal cancer is stage I, stage II, stage III or stage IV intestinal cancer according to the TNM staging standard.

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