Antibody-drug conjugate

Abstract

The present invention relates to an antibody-drug conjugate of formula (I) as defined herein, that comprises the antibody trastuzumab, for use in a method of treating endometrial cancer. The present invention also relates to the antibody-drug conjugate for use in a method of treating cancer, wherein the method comprises administering the antibody-drug conjugate or pharmaceutically acceptable salt thereof to a patient at a dose in the range of 2.2 mg / kg to 12.0 mg / kg. The present invention also relates to the antibody-drug conjugate for use in a method of treating breast cancer in patients previously treated with an anti-HER2 antibody and / or a taxane. The present invention also relates to compositions comprising the antibodydrug conjugate.

Description

[0001] ANTIBODY-DRUG CONJUGATE

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to an antibody-drug conjugate that comprises the antibody trastuzumab for use in a method of treating endometrial cancer. The present invention also relates to the antibody-drug conjugate for use in a method of treating cancer, wherein the method comprises administering the antibody-drug conjugate or pharmaceutically acceptable salt thereof to a patient at a dose in the range of 2.2 mg / kg to 12.0 mg / kg. The present invention also relates to the antibody-drug conjugate for use in a method of treating breast cancer in patients previously treated with an anti-HER2 antibody and / or a taxane. The present invention also relates to compositions comprising the antibody-drug conjugate.

[0004] BACKGROUND TO THE INVENTION

[0005] Epidermal growth factor receptor 2 (EGFR2 or HER2) has shown gene amplification / over- expression in more than 30% of all human cancers, including breast cancer, gastric, colon, salivary gland, bladder, and uterine serous carcinoma and its overexpression in tumours is associated with poor prognosis.

[0006] The clinical application of HER2-targeted therapy has improved the outcome of HER2- amplified / overexpressing patients.

[0007] Not all patients with HER2-positive tumour respond well to current therapies. Resistance towards HER2-targeting therapies is common in patients, occurring as either intrinsic or acquired resistance.

[0008] There is a need to develop cancer therapies with better therapeutic effect and / or safety.

[0009] SUMMARY OF THE INVENTION

[0010] The present invention is based, at least in part, on the inventors’ development of antibodydrug conjugates which have particularly advantageous and surprising properties.

[0011] In particular, the antibody-drug conjugate according to the invention may be particularly effective at treating cancers, such as HER2-associated cancers.

[0012] Thus, in a first aspect, the present invention provides an antibody-drug conjugate having a structure shown as formula (I):

[0013] or a pharmaceutically acceptable salt thereof, wherein:

[0014] Ab is trastuzumab; a connection number Nais an integer from 1 to 10;

[0015] I— iS "I— a"l— b"l—c",

[0016] -Lc- is -CH2-;

[0017] X1is saturated C, and X1is substituted with Rn;

[0018] Ring A is selected from the group consisting of: 3-10 membered saturated or partially unsaturated heterocyclyl and 3-10 membered saturated or partially unsaturated carbocyclyl, wherein ring A is substituted with 0 or at least 1 substituent R1a; when ring A is 3-10 membered saturated or partially unsaturated carbocyclyl, ring A is substituted with p L2, and L2is not Rn; or, when ring A is 3-10 membered saturated or partially unsaturated heterocyclyl, ring A is substituted with p L2;

[0019] L2is -R2-L3-, and R2is used for direct or indirect linking of a ligand;

[0020] L3is -(C(R3a)(R3b))m-, wherein when L3comprises a methylene unit, 0 or at least 1 methylene unit of L3is independently replaced by -N(R4)C(O)-, -C(O)N(R4)-, -C(O)-, -OC(O)-, -C(O)O-, - NR4-, -O-, -S-, -SO-, -SO2-, -P(R4)-, -P(=O)(R4)-, -N(R4)SO2-, -SO2N(R4)-, -C(=S)-, -C(=NR4)- , -N=N-, -C=N-, -N=C- or -C(=N2)-;

[0021] R2is selected from the group consisting of: -O-, -(R2a)N-, -S- and -P(=O)(R2a)-; L1is -(C(R5a)(R5b))n-, wherein when L1comprises a methylene unit, 0 or at least 1 methylene unit of L1is independently replaced by -N(R6)C(O)-, -C(O)N(R6)-, -C(O)-, -OC(O)-, -C(O)O-, - NR6-, -O-, -S-, -SO-, -SO2-, -P(R6)-, -P(=O)(R6)-, -N(R6)SO2-, -SO2N(R6)-, -C(=S)-, -C(=NR6)- , -N=N-, -C=N-, -N=C- or -C(=N2)-; wherein each R1a, each R2a, each R3a, each R3b, each R4, each R5a, each R5b, each R6and each Rnare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -CN, - OR, -SR, -N(Ra)(Rb), -C(O)R, -CO2R, -C(O)C(O)R, -C(O)CH2C(O)R, -S(O)R, -S(O)2R, - C(O)N(Ra)(Rb), -SO2N(Ra)(Rb), -OC(O)R, -N(R)SO2R, or a Ci-6aliphatic group optionally substituted with R; wherein each R, each Raand each Rbare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -CN, -OH, -SH, -NH2, -C(O)H, -CO2H, -C(O)C(O)H, - C(O)CH2C(O)H, -S(O)H, -S(O)2H, -C(O)NH2, -SO2NH2, -OC(O)H, -N(H)SO2H or a C1-6 aliphatic group; m and n are each independently selected from the group consisting of integers > 0, and p is an integer > 1 ; for use in a method of treating endometrial cancer.

[0022] Within the first aspect, the present invention provides an antibody-drug conjugate having a or a pharmaceutically acceptable salt thereof, wherein:

[0023] Ab is trastuzumab; a connection number Nais an integer from 1 to 10;

[0024] I— iS " I— a- L b- l—c- ,

[0025] -Lc- is -CH2-;

[0026] X1is saturated C, and X1is substituted with Rn; ring A is selected from the group consisting of: 3-10 membered saturated or partially unsaturated heterocyclyl and 3-10 membered saturated or partially unsaturated carbocyclyl, wherein ring A is substituted with 0 or at least 1 substituent R1a; when ring A is 3-10 membered saturated or partially unsaturated carbocyclyl, ring A is substituted with p L2, and L2is not Rn; or, when ring A is 3-10 membered saturated or partially unsaturated heterocyclyl, ring A is substituted with p L2;

[0027] L2is -R2-L3-, and R2is used for direct or indirect linking of a ligand;

[0028] L3is -(C(R3a)(R3b))m-, wherein when L3comprises a methylene unit, 0 or at least 1 methylene unit of L3is independently replaced by -N(R4)C(O)-, -C(O)N(R4)-, -C(O)-, -OC(O)-, -C(O)O-, - NR4-, -O-, -S-, -SO-, -SO2-, -P(R4)-, -P(=O)(R4)-, -N(R4)SO2-, -SO2N(R4)-, -C(=S)-, -C(=NR4)- , -N=N-, -C=N-, -N=C- or -C(=N2)-;

[0029] R2is selected from the group consisting of: -O-, -(R2a)N-, -S- and -P(=O)(R2a)-;

[0030] L1is -(C(R5a)(R5b))n-, wherein when L1comprises a methylene unit, 0 or at least 1 methylene unit of L1is independently replaced by -N(R6)C(O)-, -C(O)N(R6)-, -C(O)-, -OC(O)-, -C(O)O-, - NR6-, -O-, -S-, -SO-, -SO2-, -P(R6)-, -P(=O)(R6)-, -N(R6)SO2-, -SO2N(R6)-, -C(=S)-, -C(=NR6)- , -N=N-, -C=N-, -N=C- or -C(=N2)-; wherein each R1a, each R2a, each R3a, each R3b, each R4, each R5a, each R5b, each R6and each Rnare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, - OR, -SR, -N(Ra)(Rb), -C(O)R, -CO2R, -C(O)C(O)R, -C(O)CH2C(O)R, -S(O)R, -S(O)2R, - C(O)N(Ra)(Rb), -SO2N(Ra)(Rb), -OC(O)R, -N(R)SO2R, or a Ci-6aliphatic group optionally substituted with R; wherein each R, each Raand each Rbare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, -OH, -SH, -NH2, -C(O)H, -CO2H, -C(O)C(O)H, - C(O)CH2C(O)H, -S(O)H, -S(O)2H, -C(O)NH2, -SO2NH2, -OC(O)H, -N(H)SO2H or a C1-6 aliphatic group; m and n are each independently selected from the group consisting of integers > 0, and p is an integer > 1 ; for use in a method of treating endometrial cancer.

[0031] Within the first aspect, the present invention provides a composition comprising an antibodydrug conjugate having a structure shown as formula (I): or a pharmaceutically acceptable salt thereof, wherein:

[0032] Ab is trastuzumab; an average connection number Nais an integer or a decimal from 1 to 10;

[0033] I— iS " I— a- L b- l—c- ,

[0034] -Lc- is -CH2-;

[0035] X1is saturated C, and X1is substituted with Rn; ring A is selected from the group consisting of: 3-10 membered saturated or partially unsaturated heterocyclyl and 3-10 membered saturated or partially unsaturated carbocyclyl, wherein ring A is substituted with 0 or at least 1 substituent R1a; when ring A is 3-10 membered saturated or partially unsaturated carbocyclyl, ring A is substituted with p L2, and L2is not Rn; or, when ring A is 3-10 membered saturated or partially unsaturated heterocyclyl, ring A is substituted with p L2;

[0036] L2is -R2-L3-, and R2is used for direct or indirect linking of a ligand; L3is -(C(R3a)(R3b))m-, wherein when L3comprises a methylene unit, 0 or at least 1 methylene unit of L3is independently replaced by -N(R4)C(O)-, -C(O)N(R4)-, -C(O)-, -OC(O)-, -C(O)O-, - NR4-, -O-, -S-, -SO-, -SO2-, -P(R4)-, -P(=O)(R4)-, -N(R4)SO2-, -SO2N(R4)-, -C(=S)-, -C(=NR4)- , -N=N-, -C=N-, -N=C- or -C(=N2)-;

[0037] R2is selected from the group consisting of: -O-, -(R2a)N-, -S- and -P(=O)(R2a)-;

[0038] L1is -(C(R5a)(R5b))n-, wherein when L1comprises a methylene unit, 0 or at least 1 methylene unit of L1is independently replaced by -N(R6)C(O)-, -C(O)N(R6)-, -C(O)-, -OC(O)-, -C(O)O-, - NR6-, -O-, -S-, -SO-, -SO2-, -P(R6)-, -P(=O)(R6)-, -N(R6)SO2-, -SO2N(R6)-, -C(=S)-, -C(=NR6)- , -N=N-, -C=N-, -N=C- or -C(=N2)-; wherein each R1a, each R2a, each R3a, each R3b, each R4, each R5a, each R5b, each R6and each Rnare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, - OR, -SR, -N(Ra)(Rb), -C(O)R, -CO2R, -C(O)C(O)R, -C(O)CH2C(O)R, -S(O)R, -S(O)2R, - C(O)N(Ra)(Rb), -SO2N(Ra)(Rb), -OC(O)R, -N(R)SO2R, or a Ci-6aliphatic group optionally substituted with R; wherein each R, each Raand each Rbare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, -OH, -SH, -NH2, -C(O)H, -CO2H, -C(O)C(O)H, - C(O)CH2C(O)H, -S(O)H, -S(O)2H, -C(O)NH2, -SO2NH2, -OC(O)H, -N(H)SO2H or a C1-6 aliphatic group; m and n are each independently selected from the group consisting of integers > 0, and p is an integer > 1 ; for use in a method of treating endometrial cancer.

[0039] In a second aspect, the present invention provides an antibody-drug conjugate having a or a pharmaceutically acceptable salt thereof, wherein: Ab is trastuzumab; a connection number Nais an integer from 1 to 10;

[0040] L is -La_Lb_Lc",

[0041] -Lc- is -CH2-;

[0042] X1is saturated C, and X1is substituted with Rn; ring A is selected from the group consisting of: 3-10 membered saturated or partially unsaturated heterocyclyl and 3-10 membered saturated or partially unsaturated carbocyclyl, wherein ring A is substituted with 0 or at least 1 substituent R1a; when ring A is 3-10 membered saturated or partially unsaturated carbocyclyl, ring A is substituted with p L2, and L2is not Rn; or, when ring A is 3-10 membered saturated or partially unsaturated heterocyclyl, ring A is substituted with p L2;

[0043] L2is -R2-L3-, and R2is used for direct or indirect linking of a ligand;

[0044] L3is -(C(R3a)(R3b))m-, wherein when L3comprises a methylene unit, 0 or at least 1 methylene unit of L3is independently replaced by -N(R4)C(O)-, -C(O)N(R4)-, -C(O)-, -OC(O)-, -C(O)O-, - NR4-, -O-, -S-, -SO-, -SO2-, -P(R4)-, -P(=O)(R4)-, -N(R4)SO2-, -SO2N(R4)-, -C(=S)-, -C(=NR4)- , -N=N-, -C=N-, -N=C- or -C(=N2)-;

[0045] R2is selected from the group consisting of: -O-, -(R2a)N-, -S- and -P(=O)(R2a)-;

[0046] L1is -(C(R5a)(R5b))n-, wherein when L1comprises a methylene unit, 0 or at least 1 methylene unit of L1is independently replaced by -N(R6)C(O)-, -C(O)N(R6)-, -C(O)-, -OC(O)-, -C(O)O-, - NR6-, -O-, -S-, -SO-, -SO2-, -P(R6)-, -P(=O)(R6)-, -N(R6)SO2-, -SO2N(R6)-, -C(=S)-, -C(=NR6)- , -N=N-, -C=N-, -N=C- or -C(=N2)-; wherein each R1a, each R2a, each R3a, each R3b, each R4, each R5a, each R5b, each R6and each Rnare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, - OR, -SR, -N(Ra)(Rb), -C(O)R, -CO2R, -C(O)C(O)R, -C(O)CH2C(O)R, -S(O)R, -S(O)2R, - C(O)N(Ra)(Rb), -SO2N(Ra)(Rb), -OC(O)R, -N(R)SO2R, or a Ci-6aliphatic group optionally substituted with R; wherein each R, each Raand each Rbare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, -OH, -SH, -NH2, -C(O)H, -CO2H, -C(O)C(O)H, - C(O)CH2C(O)H, -S(O)H, -S(O)2H, -C(O)NH2, -SO2NH2, -OC(O)H, -N(H)SO2H or a C1-6 aliphatic group; m and n are each independently selected from the group consisting of integers > 0, and p is an integer > 1 ; or a pharmaceutically acceptable salt thereof, for use in a method of treating cancer, wherein the method comprises administering the antibody-drug conjugate or pharmaceutically acceptable salt thereof to a patient at a dose in the range of 2.2 mg / kg to 12.0 mg / kg.

[0047] In some embodiments of the second aspect of the invention, the dose may be in the range of 6.0 mg / kg to 10.0 mg / kg.

[0048] Within the second aspect, the present invention provides an antibody-drug conjugate having a structure shown as formula (I): or a pharmaceutically acceptable salt thereof, wherein:

[0049] Ab is trastuzumab; a connection number Nais an integer from 1 to 10;

[0050] I— iS " I— a- L b- l—c- ,

[0051] -Lc- is -CH2-;

[0052] X1is saturated C, and X1is substituted with Rn; ring A is selected from the group consisting of: 3-10 membered saturated or partially unsaturated heterocyclyl and 3-10 membered saturated or partially unsaturated carbocyclyl, wherein ring A is substituted with 0 or at least 1 substituent R1a; when ring A is 3-10 membered saturated or partially unsaturated carbocyclyl, ring A is substituted with p L2, and L2is not Rn; or, when ring A is 3-10 membered saturated or partially unsaturated heterocyclyl, ring A is substituted with p L2;

[0053] L2is -R2-L3-, and R2is used for direct or indirect linking of a ligand;

[0054] L3is -(C(R3a)(R3b))m-, wherein when L3comprises a methylene unit, 0 or at least 1 methylene unit of L3is independently replaced by -N(R4)C(O)-, -C(O)N(R4)-, -C(O)-, -OC(O)-, -C(O)O-, - NR4-, -O-, -S-, -SO-, -SO2-, -P(R4)-, -P(=O)(R4)-, -N(R4)SO2-, -SO2N(R4)-, -C(=S)-, -C(=NR4)- , -N=N-, -C=N-, -N=C- or -C(=N2)-;

[0055] R2is selected from the group consisting of: -O-, -(R2a)N-, -S- and -P(=O)(R2a)-;

[0056] L1is -(C(R5a)(R5b))n-, wherein when L1comprises a methylene unit, 0 or at least 1 methylene unit of L1is independently replaced by -N(R6)C(O)-, -C(O)N(R6)-, -C(O)-, -OC(O)-, -C(O)O-, - NR6-, -O-, -S-, -SO-, -SO2-, -P(R6)-, -P(=O)(R6)-, -N(R6)SO2-, -SO2N(R6)-, -C(=S)-, -C(=NR6)- , -N=N-, -C=N-, -N=C- or -C(=N2)-; wherein each R1a, each R2a, each R3a, each R3b, each R4, each R5a, each R5b, each R6and each Rnare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, - OR, -SR, -N(Ra)(Rb), -C(O)R, -CO2R, -C(O)C(O)R, -C(O)CH2C(O)R, -S(O)R, -S(O)2R, - C(O)N(Ra)(Rb), -SO2N(Ra)(Rb), -OC(O)R, -N(R)SO2R, or a Ci-6aliphatic group optionally substituted with R; wherein each R, each Raand each Rbare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, -OH, -SH, -NH2, -C(O)H, -CO2H, -C(O)C(O)H, - C(O)CH2C(O)H, -S(O)H, -S(O)2H, -C(O)NH2, -SO2NH2, -OC(O)H, -N(H)SO2H or a C1-6 aliphatic group; m and n are each independently selected from the group consisting of integers > 0, and p is an integer > 1 ; or a pharmaceutically acceptable salt thereof, for use in a method of treating cancer, wherein the method comprises administering the antibody-drug conjugate or pharmaceutically acceptable salt thereof to a patient at a dose in the range of 2.2 mg / kg to 12.0 mg / kg.

[0057] In some embodiments of the second aspect of the invention, the dose may be in the range of 6.0 mg / kg to 10.0 mg / kg.

[0058] Within the second aspect, the present invention provides a composition comprising an antibody-drug conjugate having a structure shown as formula (I): or a pharmaceutically acceptable salt thereof, wherein:

[0059] Ab is trastuzumab; an average connection number Nais an integer or a decimal from 1 to 10;

[0060] I— is -La-Lb-Lc-,

[0061] -Lc- is -CH2-;

[0062] X1is saturated C, and X1is substituted with Rn; ring A is selected from the group consisting of: 3-10 membered saturated or partially unsaturated heterocyclyl and 3-10 membered saturated or partially unsaturated carbocyclyl, wherein ring A is substituted with 0 or at least 1 substituent R1a; when ring A is 3-10 membered saturated or partially unsaturated carbocyclyl, ring A is substituted with p L2, and L2is not Rn; or, when ring A is 3-10 membered saturated or partially unsaturated heterocyclyl, ring A is substituted with p L2;

[0063] L2is -R2-L3-, and R2is used for direct or indirect linking of a ligand;

[0064] L3is -(C(R3a)(R3b))m-, wherein when L3comprises a methylene unit, 0 or at least 1 methylene unit of L3is independently replaced by -N(R4)C(O)-, -C(O)N(R4)-, -C(O)-, -OC(O)-, -C(O)O-, - NR4-, -O-, -S-, -SO-, -SO2-, -P(R4)-, -P(=O)(R4)-, -N(R4)SO2-, -SO2N(R4)-, -C(=S)-, -C(=NR4)- , -N=N-, -C=N-, -N=C- or -C(=N2)-; R2is selected from the group consisting of: -O-, -(R2a)N-, -S- and -P(=O)(R2a)-;

[0065] L1is -(C(R5a)(R5b))n-, wherein when L1comprises a methylene unit, 0 or at least 1 methylene unit of L1is independently replaced by -N(R6)C(O)-, -C(O)N(R6)-, -C(O)-, -OC(O)-, -C(O)O-, - NR6-, -O-, -S-, -SO-, -SO2-, -P(R6)-, -P(=O)(R6)-, -N(R6)SO2-, -SO2N(R6)-, -C(=S)-, -C(=NR6)- , -N=N-, -C=N-, -N=C- or -C(=N2)-; wherein each R1a, each R2a, each R3a, each R3b, each R4, each R5a, each R5b, each R6and each Rnare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -CN, - OR, -SR, -N(Ra)(Rb), -C(O)R, -CO2R, -C(O)C(O)R, -C(O)CH2C(O)R, -S(O)R, -S(O)2R, - C(O)N(Ra)(Rb), -SO2N(Ra)(Rb), -OC(O)R, -N(R)SO2R, or a Ci-6aliphatic group optionally substituted with R; wherein each R, each Raand each Rbare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -CN, -OH, -SH, -NH2, -C(O)H, -CO2H, -C(O)C(O)H, - C(O)CH2C(O)H, -S(O)H, -S(O)2H, -C(O)NH2, -SO2NH2, -OC(O)H, -N(H)SO2H or a C1-6 aliphatic group; m and n are each independently selected from the group consisting of integers > 0, and p is an integer > 1 ; or a pharmaceutically acceptable salt thereof, for use in a method of treating cancer, wherein the method comprises administering the antibody-drug conjugate or pharmaceutically acceptable salt thereof to a patient at a dose in the range of 2.2 mg / kg to 12.0 mg / kg.

[0066] In some embodiments of the second aspect of the invention, the dose may be in the range of 6.0 mg / kg to 10.0 mg / kg.

[0067] In a third aspect of the invention, there is provided an antibody-drug conjugate having a or a pharmaceutically acceptable salt thereof, wherein: Ab is trastuzumab; a connection number Nais an integer from 1 to 10;

[0068] L is -La_Lb_Lc",

[0069] -Lc- is -CH2-;

[0070] X1is saturated C, and X1is substituted with Rn; ring A is selected from the group consisting of: 3-10 membered saturated or partially unsaturated heterocyclyl and 3-10 membered saturated or partially unsaturated carbocyclyl, wherein ring A is substituted with 0 or at least 1 substituent R1a; when ring A is 3-10 membered saturated or partially unsaturated carbocyclyl, ring A is substituted with p L2, and L2is not Rn; or, when ring A is 3-10 membered saturated or partially unsaturated heterocyclyl, ring A is substituted with p L2;

[0071] L2is -R2-L3-, and R2is used for direct or indirect linking of a ligand;

[0072] L3is -(C(R3a)(R3b))m-, wherein when L3comprises a methylene unit, 0 or at least 1 methylene unit of L3is independently replaced by -N(R4)C(O)-, -C(O)N(R4)-, -C(O)-, -OC(O)-, -C(O)O-, - NR4-, -O-, -S-, -SO-, -SO2-, -P(R4)-, -P(=O)(R4)-, -N(R4)SO2-, -SO2N(R4)-, -C(=S)-, -C(=NR4)- , -N=N-, -C=N-, -N=C- or -C(=N2)-;

[0073] R2is selected from the group consisting of: -O-, -(R2a)N-, -S- and -P(=O)(R2a)-;

[0074] L1is -(C(R5a)(R5b))n-, wherein when L1comprises a methylene unit, 0 or at least 1 methylene unit of L1is independently replaced by -N(R6)C(O)-, -C(O)N(R6)-, -C(O)-, -OC(O)-, -C(O)O-, - NR6-, -O-, -S-, -SO-, -SO2-, -P(R6)-, -P(=O)(R6)-, -N(R6)SO2-, -SO2N(R6)-, -C(=S)-, -C(=NR6)- , -N=N-, -C=N-, -N=C- or -C(=N2)-; wherein each R1a, each R2a, each R3a, each R3b, each R4, each R5a, each R5b, each R6and each Rnare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, - OR, -SR, -N(Ra)(Rb), -C(O)R, -CO2R, -C(O)C(O)R, -C(O)CH2C(O)R, -S(O)R, -S(O)2R, - C(O)N(Ra)(Rb), -SO2N(Ra)(Rb), -OC(O)R, -N(R)SO2R, or a Ci-6aliphatic group optionally substituted with R; wherein each R, each Raand each Rbare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, -OH, -SH, -NH2, -C(O)H, -CO2H, -C(O)C(O)H, - C(O)CH2C(O)H, -S(O)H, -S(O)2H, -C(O)NH2, -SO2NH2, -OC(O)H, -N(H)SO2H or a CI.6 aliphatic group; m and n are each independently selected from the group consisting of integers > 0, and p is an integer > 1; for use in a method of treating breast cancer in a patient previously treated with an anti- HER2 antibody and / or a taxane.

[0075] Within the third aspect, the present invention provides an antibody-drug conjugate having a or a pharmaceutically acceptable salt thereof, wherein:

[0076] Ab is trastuzumab; a connection number Nais an integer from 1 to 10;

[0077] I— iS " I— a- L b- l—c- ,

[0078] -Lc- is -CH2-;

[0079] X1is saturated C, and X1is substituted with Rn; ring A is selected from the group consisting of: 3-10 membered saturated or partially unsaturated heterocyclyl and 3-10 membered saturated or partially unsaturated carbocyclyl, wherein ring A is substituted with 0 or at least 1 substituent R1a; when ring A is 3-10 membered saturated or partially unsaturated carbocyclyl, ring A is substituted with p L2, and L2is not Rn; or, when ring A is 3-10 membered saturated or partially unsaturated heterocyclyl, ring A is substituted with p L2;

[0080] L2is -R2-L3-, and R2is used for direct or indirect linking of a ligand;

[0081] L3is -(C(R3a)(R3b))m-, wherein when L3comprises a methylene unit, 0 or at least 1 methylene unit of L3is independently replaced by -N(R4)C(O)-, -C(O)N(R4)-, -C(O)-, -OC(O)-, -C(O)O-, - NR4-, -O-, -S-, -SO-, -SO2-, -P(R4)-, -P(=O)(R4)-, -N(R4)SO2-, -SO2N(R4)-, -C(=S)-, -C(=NR4)- , -N=N-, -C=N-, -N=C- or -C(=N2)-;

[0082] R2is selected from the group consisting of: -O-, -(R2a)N-, -S- and -P(=O)(R2a)-;

[0083] L1is -(C(R5a)(R5b))n-, wherein when L1comprises a methylene unit, 0 or at least 1 methylene unit of L1is independently replaced by -N(R6)C(O)-, -C(O)N(R6)-, -C(O)-, -OC(O)-, -C(O)O-, - NR6-, -O-, -S-, -SO-, -SO2-, -P(R6)-, -P(=O)(R6)-, -N(R6)SO2-, -SO2N(R6)-, -C(=S)-, -C(=NR6)- , -N=N-, -C=N-, -N=C- or -C(=N2)-; wherein each R1a, each R2a, each R3a, each R3b, each R4, each R5a, each R5b, each R6and each Rnare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, - OR, -SR, -N(Ra)(Rb), -C(O)R, -CO2R, -C(O)C(O)R, -C(O)CH2C(O)R, -S(O)R, -S(O)2R, - C(O)N(Ra)(Rb), -SO2N(Ra)(Rb), -OC(O)R, -N(R)SO2R, or a Ci-6aliphatic group optionally substituted with R; wherein each R, each Raand each Rbare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, -OH, -SH, -NH2, -C(O)H, -CO2H, -C(O)C(O)H, - C(O)CH2C(O)H, -S(O)H, -S(O)2H, -C(O)NH2, -SO2NH2, -OC(O)H, -N(H)SO2H or a C1-6 aliphatic group; m and n are each independently selected from the group consisting of integers > 0, and p is an integer > 1 ; for use in a method of treating breast cancer in a patient previously treated with an anti- HER2 antibody and / or a taxane.

[0084] Within the third aspect, the present invention provides a composition comprising an antibody-drug conjugate having a structure shown as formula (I):

[0085] or a pharmaceutically acceptable salt thereof, wherein:

[0086] Ab is trastuzumab; an average connection number Nais an integer or a decimal from 1 to 10;

[0087] I— iS "I— a"l— b"l—c",

[0088] -Lc- is -CH2-;

[0089] X1is saturated C, and X1is substituted with Rn; ring A is selected from the group consisting of: 3-10 membered saturated or partially unsaturated heterocyclyl and 3-10 membered saturated or partially unsaturated carbocyclyl, wherein ring A is substituted with 0 or at least 1 substituent R1a; when ring A is 3-10 membered saturated or partially unsaturated carbocyclyl, ring A is substituted with p L2, and L2is not Rn; or, when ring A is 3-10 membered saturated or partially unsaturated heterocyclyl, ring A is substituted with p L2;

[0090] L2is -R2-L3-, and R2is used for direct or indirect linking of a ligand;

[0091] L3is -(C(R3a)(R3b))m-, wherein when L3comprises a methylene unit, 0 or at least 1 methylene unit of L3is independently replaced by -N(R4)C(O)-, -C(O)N(R4)-, -C(O)-, -OC(O)-, -C(O)O-, - NR4-, -O-, -S-, -SO-, -SO2-, -P(R4)-, -P(=O)(R4)-, -N(R4)SO2-, -SO2N(R4)-, -C(=S)-, -C(=NR4)- , -N=N-, -C=N-, -N=C- or -C(=N2)-;

[0092] R2is selected from the group consisting of: -O-, -(R2a)N-, -S- and -P(=O)(R2a)-; L1is -(C(R5a)(R5b))n-, wherein when L1comprises a methylene unit, 0 or at least 1 methylene unit of L1is independently replaced by -N(R6)C(O)-, -C(O)N(R6)-, -C(O)-, -OC(O)-, -C(O)O-, - NR6-, -O-, -S-, -SO-, -SO2-, -P(R6)-, -P(=O)(R6)-, -N(R6)SO2-, -SO2N(R6)-, -C(=S)-, -C(=NR6)- , -N=N-, -C=N-, -N=C- or -C(=N2)-; wherein each R1a, each R2a, each R3a, each R3b, each R4, each R5a, each R5b, each R6and each Rnare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -CN, - OR, -SR, -N(Ra)(Rb), -C(O)R, -CO2R, -C(O)C(O)R, -C(O)CH2C(O)R, -S(O)R, -S(O)2R, - C(O)N(Ra)(Rb), -SO2N(Ra)(Rb), -OC(O)R, -N(R)SO2R, or a Ci-6aliphatic group optionally substituted with R; wherein each R, each Raand each Rbare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -CN, -OH, -SH, -NH2, -C(O)H, -CO2H, -C(O)C(O)H, - C(O)CH2C(O)H, -S(O)H, -S(O)2H, -C(O)NH2, -SO2NH2, -OC(O)H, -N(H)SO2H or a C1-6 aliphatic group; m and n are each independently selected from the group consisting of integers > 0, and p is an integer > 1 ; for use in a method of treating breast cancer in a patient previously treated with an anti- HER2 antibody and / or a taxane.

[0093] In some embodiments of the second aspect of the invention, the patient may have been determined to have a cancer which is a HER2 positive or HER2 overexpressive cancer.

[0094] In some embodiments of the second aspect of the invention, the patient may have been determined to have a cancer which is a HER2 low or HER2 negative cancer.

[0095] In some embodiments of the second aspect of the invention, the cancer may be selected from the group consisting of lung cancer, kidney cancer, urinary tract carcinoma, colorectal cancer, prostatic cancer, glioblastoma multiforme, ovarian cancer, pancreatic cancer, breast cancer, melanoma, liver cancer, bladder cancer, stomach cancer, esophageal cancer and endometrial cancer.

[0096] In some embodiments of the second aspect of the invention, the cancer may be selected from the group consisting of breast cancer, colorectal cancer, endometrial cancer, esophageal carcinoma, ovarian cancer, and vaginal cancer.

[0097] In some embodiments of the second aspect of the invention, the cancer may be breast cancer. In some embodiments of the second aspect of the invention, the cancer may be a HER2 positive breast cancer.

[0098] In some embodiments of the second aspect of the invention, the cancer may be a HER2 low or HER2 negative breast cancer.

[0099] In some embodiments of the second aspect of the invention, the cancer may be endometrial cancer.

[0100] In some embodiments of the second aspect of the invention, the cancer may be a HER2 positive endometrial cancer.

[0101] In some embodiments of the second aspect of the invention, the cancer may be a HER2 low or HER2 negative endometrial cancer.

[0102] In one aspect, there is provided an antibody-drug conjugate of formula (I), as defined herein, for use in the treatment of HER2-positive unresectable / metastatic breast cancer in patients who have been treated with trastuzumab and a taxane.

[0103] In some embodiments, ring A may be 4 membered saturated carbocyclyl.

[0104] In some embodiments, ring A may be substituted with 1 L2.

[0105] In some embodiments, m may be 0, and L3may be a covalent bond.

[0106] In some embodiments, n may be 1 , and L1may be -C(R5a)(R5b)- wherein 1 methylene unit of L1may be replaced by -C(O)-.

[0107] In some embodiments, the drug moiety may have the following structure l-A: wherein R2is as defined in the first or second aspect of the invention.

[0108] In some embodiments, the antibody-drug conjugate may be Compound 1 having the structure below:

[0109] Compound 1 , wherein Narepresents an average connection number, and Nais selected from the group consisting of integers or decimals from 7 to 8.

[0110] In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose in the range of 2.2 mg / kg to 12.0 mg / kg.

[0111] In some embodiments, the dose may be in the range of 6.0 mg / kg to 10.0 mg / kg.

[0112] In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 8.0 mg / kg.

[0113] In some embodiments, the antibody-drug conjugate, or pharmaceutically acceptable salt thereof may be administered once every three weeks.

[0114] In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be formulated as a composition.

[0115] In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be formulated as a composition comprising: about 20mg / ml antibody-drug conjugate or pharmaceutically acceptable salt thereof; about 25 mM histidine or a pharmaceutically acceptable salt thereof; about 9% (w / v) sucrose; and about 0.03% (w / v) polysorbate 80, and wherein the pH of the composition is about 5.5.

[0116] In one embodiment of a fourth aspect, the present invention provides a composition, typically an aqueous composition, comprising: about 20mg / ml of an antibody-drug conjugate having a structure shown as formula (I): or a pharmaceutically acceptable salt thereof, wherein:

[0117] Ab is trastuzumab; a connection number Nais an integer from 1 to 10;

[0118] I— iS " I— a- L b- l—c- ,

[0119] -Lc- is -CH2-;

[0120] X1is saturated C, and X1is substituted with Rn; ring A is selected from the group consisting of: 3-10 membered saturated or partially unsaturated heterocyclyl and 3-10 membered saturated or partially unsaturated carbocyclyl, wherein ring A is substituted with 0 or at least 1 substituent R1a; when ring A is 3-10 membered saturated or partially unsaturated carbocyclyl, ring A is substituted with p L2, and L2is not Rn; or, when ring A is 3-10 membered saturated or partially unsaturated heterocyclyl, ring A is substituted with p L2;

[0121] L2is -R2-L3-, and R2is used for direct or indirect linking of a ligand; L3is -(C(R3a)(R3b))m-, wherein when L3comprises a methylene unit, 0 or at least 1 methylene unit of L3is independently replaced by -N(R4)C(O)-, -C(O)N(R4)-, -C(O)-, -OC(O)-, -C(O)O-, - NR4-, -O-, -S-, -SO-, -SO2-, -P(R4)-, -P(=O)(R4)-, -N(R4)SO2-, -SO2N(R4)-, -C(=S)-, -C(=NR4)- , -N=N-, -C=N-, -N=C- or -C(=N2)-;

[0122] R2is selected from the group consisting of: -O-, -(R2a)N-, -S- and -P(=O)(R2a)-;

[0123] L1is -(C(R5a)(R5b))n-, wherein when L1comprises a methylene unit, 0 or at least 1 methylene unit of L1is independently replaced by -N(R6)C(O)-, -C(O)N(R6)-, -C(O)-, -OC(O)-, -C(O)O-, - NR6-, -O-, -S-, -SO-, -SO2-, -P(R6)-, -P(=O)(R6)-, -N(R6)SO2-, -SO2N(R6)-, -C(=S)-, -C(=NR6)- , -N=N-, -C=N-, -N=C- or -C(=N2)-; wherein each R1a, each R2a, each R3a, each R3b, each R4, each R5a, each R5b, each R6and each Rnare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, - OR, -SR, -N(Ra)(Rb), -C(O)R, -CO2R, -C(O)C(O)R, -C(O)CH2C(O)R, -S(O)R, -S(O)2R, - C(O)N(Ra)(Rb), -SO2N(Ra)(Rb), -OC(O)R, -N(R)SO2R, or a Ci-6aliphatic group optionally substituted with R; wherein each R, each Raand each Rbare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, -OH, -SH, -NH2, -C(O)H, -CO2H, -C(O)C(O)H, - C(O)CH2C(O)H, -S(O)H, -S(O)2H, -C(O)NH2, -SO2NH2, -OC(O)H, -N(H)SO2H or a C1-6 aliphatic group; m and n are each independently selected from the group consisting of integers > 0, and p is an integer > 1 ; about 25 mM histidine or a pharmaceutically acceptable salt thereof; about 9% (w / v) sucrose; and about 0.03% (w / v) polysorbate 80, wherein the pH of the composition is about 5.5.

[0124] In another embodiment of a fourth aspect, there is provided a composition, typically an aqueous composition, comprising: about 20mg / ml of an antibody-drug conjugate having a structure shown as formula (I):

[0125] or a pharmaceutically acceptable salt thereof, wherein:

[0126] Ab is trastuzumab; a connection number Nais an integer from 1 to 10;.

[0127] I— iS "I— a"l— b"l—c",

[0128] -Lc- is -CH2-;

[0129] X1is saturated C, and X1is substituted with Rn; ring A is selected from the group consisting of: 3-10 membered saturated or partially unsaturated heterocyclyl and 3-10 membered saturated or partially unsaturated carbocyclyl, wherein ring A is substituted with 0 or at least 1 substituent R1a; when ring A is 3-10 membered saturated or partially unsaturated carbocyclyl, ring A is substituted with p L2, and L2is not Rn; or, when ring A is 3-10 membered saturated or partially unsaturated heterocyclyl, ring A is substituted with p L2;

[0130] L2is -R2-L3-, and R2is used for direct or indirect linking of a ligand;

[0131] L3is -(C(R3a)(R3b))m-, wherein when L3comprises a methylene unit, 0 or at least 1 methylene unit of L3is independently replaced by -N(R4)C(O)-, -C(O)N(R4)-, -C(O)-, -OC(O)-, -C(O)O-, - NR4-, -O-, -S-, -SO-, -SO2-, -P(R4)-, -P(=O)(R4)-, -N(R4)SO2-, -SO2N(R4)-, -C(=S)-, -C(=NR4)- , -N=N-, -C=N-, -N=C- or -C(=N2)-;

[0132] R2is selected from the group consisting of: -O-, -(R2a)N-, -S- and -P(=O)(R2a)-; L1is -(C(R5a)(R5b))n-, wherein when L1comprises a methylene unit, 0 or at least 1 methylene unit of L1is independently replaced by -N(R6)C(O)-, -C(O)N(R6)-, -C(O)-, -OC(O)-, -C(O)O-, - NR6-, -O-, -S-, -SO-, -SO2-, -P(R6)-, -P(=O)(R6)-, -N(R6)SO2-, -SO2N(R6)-, -C(=S)-, -C(=NR6)- , -N=N-, -C=N-, -N=C- or -C(=N2)-; wherein each R1a, each R2a, each R3a, each R3b, each R4, each R5a, each R5b, each R6and each Rnare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -CN, - OR, -SR, -N(Ra)(Rb), -C(O)R, -CO2R, -C(O)C(O)R, -C(O)CH2C(O)R, -S(O)R, -S(O)2R, - C(O)N(Ra)(Rb), -SO2N(Ra)(Rb), -OC(O)R, -N(R)SO2R, or a Ci-6aliphatic group optionally substituted with R; wherein each R, each Raand each Rbare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -CN, -OH, -SH, -NH2, -C(O)H, -CO2H, -C(O)C(O)H, - C(O)CH2C(O)H, -S(O)H, -S(O)2H, -C(O)NH2, -SO2NH2, -OC(O)H, -N(H)SO2H or a C1-6 aliphatic group; m and n are each independently selected from the group consisting of integers > 0, and p is an integer > 1 ; about 0.82 mg / ml L-histidine; about 4.14 mg / ml L-histidine hydrochloride monohydrate; about 90 mg / ml sucrose; and about 0.3 mg / ml polysorbate 80.

[0133] In one embodiment of a fifth aspect, the present invention also provides a lyophilized composition comprising:

[0134] (a) about 100mg of an antibody-drug conjugate having a structure shown as formula (I): or a pharmaceutically acceptable salt thereof, wherein:

[0135] Ab is trastuzumab; a connection number Nais an integer from 1 to 10; I— is -La-Lb-Lc-,

[0136] -Lc- is -CH2-;

[0137] X1is saturated C, and X1is substituted with Rn; ring A is selected from the group consisting of: 3-10 membered saturated or partially unsaturated heterocyclyl and 3-10 membered saturated or partially unsaturated carbocyclyl, wherein ring A is substituted with 0 or at least 1 substituent R1a; when ring A is 3-10 membered saturated or partially unsaturated carbocyclyl, ring A is substituted with p L2, and L2is not Rn; or, when ring A is 3-10 membered saturated or partially unsaturated heterocyclyl, ring A is substituted with p L2;

[0138] L2is -R2-L3-, and R2is used for direct or indirect linking of a ligand;

[0139] L3is -(C(R3a)(R3b))m-, wherein when L3comprises a methylene unit, 0 or at least 1 methylene unit of L3is independently replaced by -N(R4)C(O)-, -C(O)N(R4)-, -C(O)-, -OC(O)-, -C(O)O-, - NR4-, -O-, -S-, -SO-, -SO2-, -P(R4)-, -P(=O)(R4)-, -N(R4)SO2-, -SO2N(R4)-, -C(=S)-, -C(=NR4)- , -N=N-, -C=N-, -N=C- or -C(=N2)-;

[0140] R2is selected from the group consisting of: -O-, -(R2a)N-, -S- and -P(=O)(R2a)-;

[0141] L1is -(C(R5a)(R5b))n-, wherein when L1comprises a methylene unit, 0 or at least 1 methylene unit of L1is independently replaced by -N(R6)C(O)-, -C(O)N(R6)-, -C(O)-, -OC(O)-, -C(O)O-, - NR6-, -O-, -S-, -SO-, -SO2-, -P(R6)-, -P(=O)(R6)-, -N(R6)SO2-, -SO2N(R6)-, -C(=S)-, -C(=NR6)- , -N=N-, -C=N-, -N=C- or -C(=N2)-; wherein each R1a, each R2a, each R3a, each R3b, each R4, each R5a, each R5b, each R6and each Rnare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, - OR, -SR, -N(Ra)(Rb), -C(O)R, -CO2R, -C(O)C(O)R, -C(O)CH2C(O)R, -S(O)R, -S(O)2R, - C(O)N(Ra)(Rb), -SO2N(Ra)(Rb), -OC(O)R, -N(R)SO2R, or a Ci-6aliphatic group optionally substituted with R; wherein each R, each Raand each Rbare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, -OH, -SH, -NH2, -C(O)H, -CO2H, -C(O)C(O)H, - C(O)CH2C(O)H, -S(O)H, -S(O)2H, -C(O)NH2, -SO2NH2, -OC(O)H, -N(H)SO2H or a C1-6 aliphatic group; m and n are each independently selected from the group consisting of integers > 0, and p is an integer > 1;

[0142] (b) about 4.1 mg L-histidine;

[0143] (c) about 20.7 mg L-histidine hydrochloride monohydrate;

[0144] (d) about 450 mg sucrose; and

[0145] (e) about 1.5 mg polysorbate 80.

[0146] In another embodiment of the fifth aspect, the present invention also provides a lyophilized composition comprising:

[0147] (a) an antibody-drug conjugate having a structure shown as formula (I): or a pharmaceutically acceptable salt thereof, wherein:

[0148] Ab is trastuzumab; a connection number Nais an integer from 1 to 10;

[0149] I— iS " I— a- L b- l—c- ,

[0150] -Lc- is -CH2-;

[0151] X1is saturated C, and X1is substituted with Rn; ring A is selected from the group consisting of: 3-10 membered saturated or partially unsaturated heterocyclyl and 3-10 membered saturated or partially unsaturated carbocyclyl, wherein ring A is substituted with 0 or at least 1 substituent R1a; when ring A is 3-10 membered saturated or partially unsaturated carbocyclyl, ring A is substituted with p L2, and L2is not Rn; or, when ring A is 3-10 membered saturated or partially unsaturated heterocyclyl, ring A is substituted with p L2;

[0152] L2is -R2-L3-, and R2is used for direct or indirect linking of a ligand;

[0153] L3is -(C(R3a)(R3b))m-, wherein when L3comprises a methylene unit, 0 or at least 1 methylene unit of L3is independently replaced by -N(R4)C(O)-, -C(O)N(R4)-, -C(O)-, -OC(O)-, -C(O)O-, - NR4-, -O-, -S-, -SO-, -SO2-, -P(R4)-, -P(=O)(R4)-, -N(R4)SO2-, -SO2N(R4)-, -C(=S)-, -C(=NR4)- , -N=N-, -C=N-, -N=C- or -C(=N2)-;

[0154] R2is selected from the group consisting of: -O-, -(R2a)N-, -S- and -P(=O)(R2a)-;

[0155] L1is -(C(R5a)(R5b))n-, wherein when L1comprises a methylene unit, 0 or at least 1 methylene unit of L1is independently replaced by -N(R6)C(O)-, -C(O)N(R6)-, -C(O)-, -OC(O)-, -C(O)O-, - NR6-, -O-, -S-, -SO-, -SO2-, -P(R6)-, -P(=O)(R6)-, -N(R6)SO2-, -SO2N(R6)-, -C(=S)-, -C(=NR6)- , -N=N-, -C=N-, -N=C- or -C(=N2)-; wherein each R1a, each R2a, each R3a, each R3b, each R4, each R5a, each R5b, each R6and each Rnare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, - OR, -SR, -N(Ra)(Rb), -C(O)R, -CO2R, -C(O)C(O)R, -C(O)CH2C(O)R, -S(O)R, -S(O)2R, - C(O)N(Ra)(Rb), -SO2N(Ra)(Rb), -OC(O)R, -N(R)SO2R, or a Ci-6aliphatic group optionally substituted with R; wherein each R, each Raand each Rbare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, -OH, -SH, -NH2, -C(O)H, -CO2H, -C(O)C(O)H, - C(O)CH2C(O)H, -S(O)H, -S(O)2H, -C(O)NH2, -SO2NH2, -OC(O)H, -N(H)SO2H or a C1-6 aliphatic group; m and n are each independently selected from the group consisting of integers > 0, and p is an integer > 1 ; in an amount of about 100 parts by weight;

[0156] (b) L-histidine, in an amount of about 4.1 parts by weight, relative to 100 parts by weight (a);

[0157] (c) L-histidine hydrochloride monohydrate; in an amount of about 20.7 parts by weight, relative to 100 parts by weight (a);

[0158] (d) sucrose, in an amount of about 450 parts by weight, relative to 100 parts by weight (a); and

[0159] (e) polysorbate 80, in an amount of about 1.5 parts by weight, relative to 100 parts by weight (a).

[0160] In a sixth aspect, the present invention provides a method of preparing the composition of the fourth aspect, the method comprising reconstituting the lyophilized composition of the fifth aspect with a diluent. In one embodiment, the diluent is water, typically purified water as defined herein. In one embodiment, the water is Water For Injection (WFI).

[0161] In a seventh aspect, the present invention provides a method of preparing the lyophilized composition of the fifth aspect, the method comprising lyophilizing the composition of the fourth aspect.

[0162] In an eighth aspect, the present invention provides a lyophilized composition obtainable by the method of the seventh aspect.

[0163] BRIEF DESCRIPTION OF THE FIGURES

[0164] Figure 1 shows the best overall tumour change from baseline according to the data available as of May 8, 2023;

[0165] Figure 2 shows the depth and duration of response according to the data available as of May 8, 2023;

[0166] Figure 3 shows the best overall tumour change from baseline in efficacy-evaluable subjects according to the data available as of July 26, 2023;

[0167] Figure 4 shows the best overall tumour change from baseline in efficacy-evaluable subjects, according to the data available as of December 14, 2023; and

[0168] Figure 5 shows the depth and duration of response in efficacy-evaluable subjects according to the data available as of December 14, 2023.

[0169] DETAILED DESCRIPTION OF THE INVENTION

[0170] ANTIBODY-DRUG CONJUGATE AND COMPOSITION INCLUDING IT

[0171] The present invention generally relates to antibody-drug conjugates (ADCs) and compositions including them.

[0172] ADCs are a class of targeted therapeutics that improves both the selectivity and the cytotoxic activity of drugs, such as cancer drugs, by targeting the drugs to specific targets such as cancer cells.

[0173] In general, ADCs comprise three main components: (i) an antibody (such as a monoclonal antibody) conjugated to (ii) a linker, which in turn is also conjugated to (iii) a cargo or payload (such as a cytotoxic or chemotherapeutic drug). The cytotoxic or chemotherapeutic drug refers to a drug that reduces or eliminates the viability of a cell. Suitable cytotoxic or chemotherapeutic drugs will be known in the art. It will be understood by the person skilled in the art that all references in this specification to the term “antibody-drug conjugate” will also include compositions comprising mixtures of antibody-drug conjugates, each which may have different drug-antibody ratios (DARs). These are described in more detail below with reference to compositions. The drug-antibody ratio (DAR) of the antibody-drug conjugates as described herein may vary. Consequently, the composition may comprise a mixture of antibody-drug conjugates having a number of different DARs, and may therefore have an average DAR which is non-integral. In this specification, the terms “DAR” and “connection number” are synonymous, and the terms “average DAR” and “average connection number” are synonymous.

[0174] It will be understood that the term “DAR” or “connection number” when referring to a specific antibody-drug conjugate refers to the number of drug molecules connected (e.g. conjugated) to the antibody, optionally via linkers, in any single antibody-drug conjugate. Thus, the connection number (referred to herein as “n”) can be considered as the specific number of linker-payload structures conjugated to the antibody in a given antibody-drug conjugate. It will also be understood that the connection number n can affect the safety and therapeutic effectiveness of the antibody-drug conjugate. The number of drug molecules per antibody molecule, also referred to herein as the drug-antibody ratio (DAR), can be characterized by conventional methods such as UV / visible spectroscopy, mass spectrometry, ELISA assays and HPLC.

[0175] The present inventors have surprisingly found that the antibody-drug conjugates according to the invention are particularly effective at treating cancers, such as HER2-associated cancers.

[0176] In a first aspect according to the present invention, there is provided an antibody-drug conjugate having a structure shown as formula (I): or a pharmaceutically acceptable salt thereof, wherein:

[0177] Ab is trastuzumab; a connection number Nais an integer from 1 to 10;

[0178] I— iS "I— a"l— b"l—c",

[0179] -Lc- is -CH2-;

[0180] X1is saturated C, and X1is substituted with Rn; ring A is selected from the group consisting of: 3-10 membered saturated or partially unsaturated heterocyclyl and 3-10 membered saturated or partially unsaturated carbocyclyl, wherein ring A is substituted with 0 or at least 1 substituent R1a; when ring A is 3-10 membered saturated or partially unsaturated carbocyclyl, ring A is substituted with p L2, and L2is not Rn; or, when ring A is 3-10 membered saturated or partially unsaturated heterocyclyl, ring A is substituted with p L2;

[0181] L2is -R2-L3-, and R2is used for direct or indirect linking of a ligand;

[0182] L3is -(C(R3a)(R3b))m-, wherein when L3comprises a methylene unit, 0 or at least 1 methylene unit of L3is independently replaced by -N(R4)C(O)-, -C(O)N(R4)-, -C(O)-, -OC(O)-, -C(O)O-, - NR4-, -O-, -S-, -SO-, -SO2-, -P(R4)-, -P(=O)(R4)-, -N(R4)SO2-, -SO2N(R4)-, -C(=S)-, -C(=NR4)-, -N=N-, -C=N-, -N=C- or -C(=N2)-;

[0183] R2is selected from the group consisting of: -O-, -(R2a)N-, -S- and -P(=O)(R2a)-;

[0184] L1is -(C(R5a)(R5b))n-, wherein when L1comprises a methylene unit, 0 or at least 1 methylene unit of L1is independently replaced by -N(R6)C(O)-, -C(O)N(R6)-, -C(O)-, -OC(O)-, -C(O)O-, - NR6-, -O-, -S-, -SO-, -SO2-, -P(R6)-, -P(=O)(R6)-, -N(R6)SO2-, -SO2N(R6)-, -C(=S)-, -C(=NR6)-, -N=N-, -C=N-, -N=C- or -C(=N2)-; wherein each R1a, each R2a, each R3a, each R3b, each R4, each R5a, each R5b, each R6and each Rnare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, - OR, -SR, -N(Ra)(Rb), -C(O)R, -CO2R, -C(O)C(O)R, -C(O)CH2C(O)R, -S(O)R, -S(O)2R, - C(O)N(Ra)(Rb), -SO2N(Ra)(Rb), -OC(O)R, -N(R)SO2R, or a Ci-6aliphatic group optionally substituted with R; wherein each R, each Raand each Rbare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -CN, -OH, -SH, -NH2, -C(O)H, -CO2H, -C(O)C(O)H, -C(O)CH2C(O)H, - S(O)H, -S(O)2H, -C(O)NH2, -SO2NH2, -OC(O)H, -N(H)SO2H or a Ci-6aliphatic group; m and n are each independently selected from the group consisting of integers > 0, and p is an integer > 1 ; for use in a method of treating endometrial cancer.

[0185] Within the first aspect, the present invention provides an antibody-drug conjugate having a or a pharmaceutically acceptable salt thereof, wherein:

[0186] Ab is trastuzumab; a connection number Nais an integer from 1 to 10;

[0187] I— iS " I— a- L b- l—c- ,

[0188] -Lc- is -CH2-;

[0189] X1is saturated C, and X1is substituted with Rn; ring A is selected from the group consisting of: 3-10 membered saturated or partially unsaturated heterocyclyl and 3-10 membered saturated or partially unsaturated carbocyclyl, wherein ring A is substituted with 0 or at least 1 substituent R1a; when ring A is 3-10 membered saturated or partially unsaturated carbocyclyl, ring A is substituted with p L2, and L2is not Rn; or, when ring A is 3-10 membered saturated or partially unsaturated heterocyclyl, ring A is substituted with p L2;

[0190] L2is -R2-L3-, and R2is used for direct or indirect linking of a ligand;

[0191] L3is -(C(R3a)(R3b))m-, wherein when L3comprises a methylene unit, 0 or at least 1 methylene unit of L3is independently replaced by -N(R4)C(O)-, -C(O)N(R4)-, -C(O)-, -OC(O)-, -C(O)O-, - NR4-, -O-, -S-, -SO-, -SO2-, -P(R4)-, -P(=O)(R4)-, -N(R4)SO2-, -SO2N(R4)-, -C(=S)-, -C(=NR4)-, -N=N-, -C=N-, -N=C- or -C(=N2)-;

[0192] R2is selected from the group consisting of: -O-, -(R2a)N-, -S- and -P(=O)(R2a)-;

[0193] L1is -(C(R5a)(R5b))n-, wherein when L1comprises a methylene unit, 0 or at least 1 methylene unit of L1is independently replaced by -N(R6)C(O)-, -C(O)N(R6)-, -C(O)-, -OC(O)-, -C(O)O-, - NR6-, -O-, -S-, -SO-, -SO2-, -P(R6)-, -P(=O)(R6)-, -N(R6)SO2-, -SO2N(R6)-, -C(=S)-, -C(=NR6)-, -N=N-, -C=N-, -N=C- or -C(=N2)-; wherein each R1a, each R2a, each R3a, each R3b, each R4, each R5a, each R5b, each R6and each Rnare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, - OR, -SR, -N(Ra)(Rb), -C(O)R, -CO2R, -C(O)C(O)R, -C(O)CH2C(O)R, -S(O)R, -S(O)2R, - C(O)N(Ra)(Rb), -SO2N(Ra)(Rb), -OC(O)R, -N(R)SO2R, or a Ci-6aliphatic group optionally substituted with R; wherein each R, each Raand each Rbare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, -OH, -SH, -NH2, -C(O)H, -CO2H, -C(O)C(O)H, -C(O)CH2C(O)H, - S(O)H, -S(O)2H, -C(O)NH2, -SO2NH2, -OC(O)H, -N(H)SO2H or a Ci-6aliphatic group; m and n are each independently selected from the group consisting of integers > 0, and p is an integer > 1 ; for use in a method of treating endometrial cancer.

[0194] Within the first aspect, the present invention provides a composition comprising an antibodydrug conjugate having a structure shown as formula (I):

[0195] or a pharmaceutically acceptable salt thereof, wherein:

[0196] Ab is trastuzumab; an average connection number Nais an integer or a decimal from 1 to 10;

[0197] I— is -La-Lb-Lc-,

[0198] La- is

[0199] -Lc- is -CH2-;

[0200] X1is saturated C, and X1is substituted with Rn; ring A is selected from the group consisting of: 3-10 membered saturated or partially unsaturated heterocyclyl and 3-10 membered saturated or partially unsaturated carbocyclyl, wherein ring A is substituted with 0 or at least 1 substituent R1a; when ring A is 3-10 membered saturated or partially unsaturated carbocyclyl, ring A is substituted with p L2, and L2is not Rn; or, when ring A is 3-10 membered saturated or partially unsaturated heterocyclyl, ring A is substituted with p L2;

[0201] L2is -R2-L3-, and R2is used for direct or indirect linking of a ligand;

[0202] L3is -(C(R3a)(R3b))m-, wherein when L3comprises a methylene unit, 0 or at least 1 methylene unit of L3is independently replaced by -N(R4)C(O)-, -C(O)N(R4)-, -C(O)-, -OC(O)-, -C(O)O-, - NR4-, -0-, -S-, -SO-, -SO2-, -P(R4)-, -P(=O)(R4)-, -N(R4)SO2-, -SO2N(R4)-, -C(=S)-, -C(=NR4)-, -N=N-, -C=N-, -N=C- or -C(=N2)-;

[0203] R2is selected from the group consisting of: -O-, -(R2a)N-, -S- and -P(=O)(R2a)-;

[0204] L1is -(C(R5a)(R5b))n-, wherein when L1comprises a methylene unit, 0 or at least 1 methylene unit of L1is independently replaced by -N(R6)C(O)-, -C(O)N(R6)-, -C(O)-, -OC(O)-, -C(O)O-, - NR6-, -O-, -S-, -SO-, -SO2-, -P(R6)-, -P(=O)(R6)-, -N(R6)SO2-, -SO2N(R6)-, -C(=S)-, -C(=NR6)-, -N=N-, -C=N-, -N=C- or -C(=N2)-; wherein each R1a, each R2a, each R3a, each R3b, each R4, each R5a, each R5b, each R6and each Rnare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, - OR, -SR, -N(Ra)(Rb), -C(O)R, -CO2R, -C(O)C(O)R, -C(O)CH2C(O)R, -S(O)R, -S(O)2R, - C(O)N(Ra)(Rb), -SO2N(Ra)(Rb), -OC(O)R, -N(R)SO2R, or a Ci-6aliphatic group optionally substituted with R; wherein each R, each Raand each Rbare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, -OH, -SH, -NH2, -C(O)H, -CO2H, -C(O)C(O)H, -C(O)CH2C(O)H, - S(O)H, -S(O)2H, -C(O)NH2, -SO2NH2, -OC(O)H, -N(H)SO2H or a Ci-6aliphatic group; m and n are each independently selected from the group consisting of integers > 0, and p is an integer > 1 ; for use in a method of treating endometrial cancer.

[0205] In a second aspect according to the present invention, there is provided an antibody-drug conjugate having a structure shown as formula (I) as defined above, either in its broadest aspect or a preferred aspect, or a pharmaceutically acceptable salt thereof, for use in a method of treating cancer, wherein the method comprises administering the antibody-drug conjugate or pharmaceutically acceptable salt thereof to a patient at a dose in the range of 6.0 mg / kg to 10.0 mg / kg.

[0206] The compounds of formula (I) and general and specific methods for their synthesis are disclosed as compounds of formula (ll-Dx) in WO2022 / 068878 and published national applications derived therefrom.

[0207] The present invention also relates to compositions containing antibody-drug conjugates (ADCs) as defined herein, and mixtures thereof, for uses as defined herein. It will be understood by the person skilled in the art that the composition may comprise multiple antibody-drug conjugates, and that the drug-antibody ratio (as defined herein) of each antibody-drug conjugate may be the same or different. In contrast to the term “connection number” when used alone, it will be understood that the term “average connection number Na” in the context of a composition containing antibodydrug conjugates refers to the average number of drug molecules connected (e.g. conjugated) to the antibody in all of the ADCs present in the composition. Thus, the “average connection number Na” can be considered as the average number of linked payload (e.g. cytotoxic drugs) per antibody in a given composition. As the skilled person will readily understand, the average connection number may therefore be an integer or be non-integral. It will also be understood that the average connection number Nacan affect the safety and therapeutic effectiveness of the antibody-drug conjugate. The number of drug molecules per antibody molecule can be characterized by conventional methods such as UV / visible spectroscopy, mass spectrometry, ELISA assays and HPLC.

[0208] Herein it will be understood that the average connection number Nais relevant (and may be non-integral) when the ADC is included within a composition whilst a single ADC will have a connection number which is an integer from 1 to 10.

[0209] As used herein, the average connection number Nais an integer or a decimal from 1 to 10.

[0210] As used herein, the connection number Nais an integer from 1 to 10.

[0211] In some embodiments, the average connection number Namay be an integer or a decimal selected from the list of ranges selected from: 1 to 10, 1 to 9, 1 to 8, 1 to 7, 1 to 6, 1 to 5, 1 to 4, 1 to 3, or 1 to 2.

[0212] In some embodiments, the connection number Namay be an integer selected from the list of ranges selected from: 1 to 10, 1 to 9, 1 to 8, 1 to 7, 1 to 6, 1 to 5, 1 to 4, 1 to 3, or 1 to 2.

[0213] In some embodiments, the average connection number Namay be an integer or a decimal selected from the list of ranges selected from: 1 to 10, 2 to 10, 3 to 10, 4 to 10, 5 to 10, 6 to 10, 7 to 10, 8 to 10, or 9 to 10.

[0214] In some embodiments, the connection number Namay be an integer selected from the list of ranges selected from: 1 to 10, 2 to 10, 3 to 10, 4 to 10, 5 to 10, 6 to 10, 7 to 10, 8 to 10, or 9 to 10. In some embodiments, the average connection number Namay be an integer or a decimal selected from the list of ranges selected from: 1 to 2, 2 to 3, 3 to 4, 4 to 5, 5 to 6, 6 to 7, 7 to 8, 8 to 9, or 9 to 10.

[0215] In some embodiments, the connection number Namay be an integer selected from the list of ranges selected from: 1 to 2, 2 to 3, 3 to 4, 4 to 5, 5 to 6, 6 to 7, 7 to 8, 8 to 9, or 9 to 10.

[0216] In some embodiments, the average connection number Namay be an integer or a decimal selected from the list of ranges selected from: 1 to 8, 2 to 8, 3 to 8, 4 to 8, 5 to 8, 6 to 8, or 7 to 8.

[0217] In some embodiments, the connection number Namay be an integer selected from the list of ranges selected from: 1 to 8, 2 to 8, 3 to 8, 4 to 8, 5 to 8, 6 to 8, or 7 to 8.

[0218] In some embodiments, the average connection number Namay be selected from the group of integers of: 1 , 2, 3, 4, 5, 6, 7, 8, 9, or 10.

[0219] In some embodiments, the connection number Namay be selected from the group of integers of: 1 , 2, 3, 4, 5, 6, 7, 8, 9, or 10.

[0220] In some embodiments, the average connection number Namay be selected from the group of integers or decimals of about: 1.0, 1.1 , 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1 , 2.2, 2.3,

[0221] 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1 , 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1 , 4.2, 4.3, 4.4,

[0222] 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1 , 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1 , 6.2, 6.3, 6.4, 6.5,

[0223] 6.6, 6.7, 6.8, 6.9, 7.0, 7.1 , 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1 , 8.2, 8.3, 8.4, 8.5, 8.6,

[0224] 8.7, 8.8, 8.9, 9.0, 9.1 , 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, or 10.0.

[0225] In some embodiments, the average connection number Namay be an integer or a decimal selected from the range of about 7 to about 8. In some embodiments, the average connection number Namay be an integer or a decimal selected from the range of about 7.5 to about 8. In some embodiments, the average connection number Namay be an integer or a decimal selected from the range of about 7.6 to about 8. In some embodiments, the average connection number Namay be selected from the group of integers or decimals of about: 7.0, 7.1 , 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0.

[0226] In some embodiments, the antibody-drug conjugate or a pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.5 to about 8. In some embodiments, the antibody-drug conjugate or a pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.6 to about 8. In some embodiments, the antibody-drug conjugate or a pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be selected from the group of integers or decimals of about: 7.0, 7.1 , 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0.

[0227] It will be understood that the term “pharmaceutically acceptable salt” has the generally known meaning of an ionic assembly of anions and cations, where one of the ions is the compound used in the present invention and the other ion is a non-toxic counter-ion.

[0228] In some embodiments the pharmaceutically acceptable salt may be a sodium salt or a potassium salt. In some embodiments the pharmaceutically acceptable salt may be a sodium salt. In some embodiments the pharmaceutically acceptable salt may be a potassium salt.

[0229] In one embodiment of the antibody-drug conjugate for use according to the present invention, the antibody component, the drug component, and / or if present, the linker component, may take the structures shown herein. In another embodiment, the antibody component, the drug component, and / or if present, the linker component of the antibody-drug conjugate for use in the present invention may take the form of a tautomer, a mesomer, a racemate, an enantiomer or a diastereoisomer of any of the structures shown, or a mixture thereof.

[0230] In some embodiments, the antibody-drug conjugate may be Compound 1 , having the structure below: wherein Narepresents an average connection number, and Nais selected from the group consisting of integers or decimals from 7 to 8.

[0231] Compound 1 is disclosed as compound ADC-ll-9 and general and specific methods for its synthesis are disclosed in WO2022 / 068878 and published national applications derived therefrom. Compound 1 has received the LISAN trastuzumab pamirtecan.

[0232] In some embodiments of any of the aspects of the invention, the antibody-drug conjugate is trastuzumab pamirtecan or a pharmaceutically acceptable salt thereof.

[0233] The antibody component and the drug component of the antibody-drug conjugate of the invention are linked (i.e. conjugated) to each other via the linker as defined in the claims.

[0234] Such linkers typically have chemically reactive groups at each end. These linkers can form a covalent attachment between two molecules, e.g. the antibody and the drug. Thus, the antibody and the drug may be covalently linked to a linker. Suitably, one region of the linker may bind to the antibody and another region of the linker may bind to the drug.

[0235] In some embodiments, the linker may be a cleavable linker. In some embodiments, the linker may be a maleimide tetrapeptide-based cleavable linker.

[0236] Without wishing to be bound by theory, the antibody-drug conjugate according to the invention may have (but is not limited to) one or more of the following features:

[0237] • High potency of payload;

[0238] • High drug-to-antibody ratio;

[0239] • Stable linker-payload;

[0240] • Tumour-selective cleavable linker;

[0241] • Selectively endocytosed into the lysosome of HER2-positive cell; and / or

[0242] • ADCC activity and bystander antitumour effect.

[0243] Without wishing to be bound by theory, as described herein and in WO2022 / 068878 and published national applications derived therefrom, Compound 1 also exhibits the following improved properties compared with the marketed ADC trastuzumab deruxtecan (Enhertu®, referred to therein as Reference ADC-1);

[0244] • improved in vitro anti-proliferative activity, compared with trastuzumab deruxtecan, against tumour cell lines NCI-N87 (gastric cancer) and JIMT-1 (breast cancer);

[0245] • improved plasma stability, compared with trastuzumab deruxtecan; • reduction in tumour volume, and improved in vivo tumour inhibition effect, compared with trastuzumab deruxtecan in xenograft mice bearing the cell line NCI-N87 (gastric cancer);

[0246] • reduction in tumour volume, and improved in vivo tumour inhibition effect, compared with trastuzumab deruxtecan in xenograft mice bearing the cell line JIMT-1 (breast cancer); and

[0247] • an improved safety profile, including but not limited to the improved safety and adverse events detailed in Example 5 herein, such as gastrointestinal events and alopecia, compared with trastuzumab deruxtecan.

[0248] ANTIBODY

[0249] The antibody-drug conjugate comprises an anti-HER2 antibody or fragment thereof. The anti-HER2 antibody or fragment thereof may specifically bind HER2. The anti-HER2 antibody may be a monoclonal antibody. In some embodiments, the anti-HER2 antibody or fragment thereof is a humanized antibody. In some embodiments, the anti-HER2 antibody or fragment thereof is a monoclonal humanized antibody. The fragment thereof may be any antigen-binding fragment thereof, for example a Fab, a Fab', a F(ab')2, a Fv, a scFv, a Fab'- SH, an sdAb, or a VHH. In some embodiments, the anti- HER2 antibody or fragment thereof is a full-length anti-HER2 antibody.

[0250] The anti-HER2 antibody or fragment thereof may comprise a variable region that specifically binds HER2. In some embodiments, the anti- HER2 antibody or fragment thereof comprises a heavy chain variable region and / or a light chain variable domain. In some embodiments, the anti-HER2 antibody or fragment thereof comprises a heavy chain variable region and a light chain variable domain. In some embodiments, the anti-HER2 antibody or fragment thereof comprises a constant region, preferably derived from a human antibody, preferably the constant region is selected from the constant region of human lgG1, lgG2, lgG3 or lgG4. In some embodiments, the anti-HER2 antibody or fragment thereof comprises a heavy chain and / or a light chain. In some embodiments, the anti- HER2 antibody or fragment thereof comprises a heavy chain and a light chain. In some embodiments, the anti- HER2 antibody or fragment thereof comprises or consists of two heavy chains and two light chains.

[0251] It will be understood that the terms “binding to”, “binds”, “targeting” and “targets” are interchangeable.

[0252] Antibodies described herein include polyclonal and monoclonal antibodies and include IgA such as lgA1 or lgA2, IgG such as lgG1 , lgG2, lgG3, or lgG4, IgE, IgM, and IgD antibodies. In various embodiments, the antibody is an lgG1 antibody, more particularly an lgG1 , kappa or lgG1 , lambda isotype (i.e. lgG1, K, A), an lgG2a antibody (e.g. lgG2a, K, A), an lgG2b antibody (e.g. lgG2b, K, A), an lgG3 antibody (e.g. I gG3, K, A) or an lgG4 antibody (e.g. I gG4, K, A). In preferred embodiments the antibody is an lgG1, preferably lgG1 , lambda.

[0253] The antibody may be of any species (for example human, monkey, camel, llama, goat, sheep, rabbit, mouse, rat, hamster or chicken) or it may be a hybrid derived from more than one species. It may be naturally occurring or it may be non-naturally occurring (i.e. an isolated antibody). The antibody may be created by genetic engineering (for example a chimeric antibody, humanised antibody, camelised antibody, intrabody, bispecific antibody).

[0254] “Antibodies” are glycoproteins belonging to the immunoglobulin superfamily. The term "full- length antibody" may refer to an immunoglobulin molecule that binds to a target molecule and contains four peptide chains: two heavy chains and two light chains which are connected to each other through disulfide bonds. Antibodies may comprise several “regions” or “domains” and the terms may be used interchangeably herein. An antibody may recognise an antigen via the fragment antigen-binding (Fab) variable region. The fragment crystallizable region (Fc region) is the tail region of an antibody that may allow antibodies to activate the immune system. The hinge region is a stretch of heavy chains linking the Fab and Fc regions. The heavy chain and light chain may each comprise a variable domain and one or more constant domains. For example, in IgG antibodies, a heavy chain comprises a variable domain (VH) and three constant domains (CH1 , CH2, and CH3) and a light chain comprises a variable domain (VL) and one constant domain (CL). Example antibodies include a human antibody, a humanized antibody, a chimeric antibody, a multispecific antibody, a monoclonal antibody, and a polyclonal antibody.

[0255] The term “antibody fragment” may refer to a fragment of an antibody, or a genetically engineered product of one of more fragments of an antibody, which fragment is involved in binding with the target molecule. Examples of antibody fragments include an antigen-binding fragment (Fab), a Fab', a Fab'-SH, a fragment antibody (F(ab’)2), a variable region (Fv), a single chain variable fragment (scFv), a single-domain antibody (sdAb), a nanobody, a VHH, and a camelid antibody. The term “Antigen-binding fragment” or “Fab” refers to a region of an antibody that binds to antigens and is composed of one constant and one variable region of each of the heavy and the light chain. The term “fragment antibody” or “F(ab’)2” refers to a region of an antibody that remains following digestion of the Fc region while leaving intact some of the hinge region. The term “Fab”’ refers to a fragment formed by the reduction of a F(ab')2 fragment. The term “Fab’-SH” refers to a Fab’ fragment with a free sulfhydryl group. The term “Single chain variable fragment” or “scFv” refers to an engineered antibody consisting of a light chain variable region and a heavy chain variable region which are connected to each other.

[0256] “Variable regions” as used herein means a segment of an antibody which contains three CDRs, designated CDR1 , CDR2 and CDR3. A “variable region” of an antibody refers to the variable region of the antibody light chain or the variable region of the antibody heavy chain, either alone or in combination. The variable region of the heavy chain may be referred to as “VH.” The variable region of the light chain may be referred to as “VL.” Typically, the variable regions of both the heavy and light chains comprise three hypervariable regions, the CDRs, which are located within relatively conserved framework regions (FR). The CDRs are usually aligned by the framework regions, enabling binding to a specific epitope. In general, from N- terminal to C-terminal, both light and heavy chains variable domains comprise FR1, CDR1, FR2, CDR2, FR3, CDR3, and FR4.

[0257] The term “heavy chain” refers to a large protein subunit of an immunoglobulin. Heavy chains can be of any immunoglobulin isotype (for example IgG, IgE, IgM, IgD, IgA or IgY), subtype (for example lgG1, lgG2, lgG2a, lgG2b, lgG2c, lgG3, lgG-4, lgA1 or lgA2) or allotype.

[0258] The term “light chain” refers to a small protein subunit of an immunoglobulin. Light chains can be of any type (for example kappa or lambda), subtype or allotype.

[0259] “CDR” or “CDRs” means complementarity determining region(s) in an immunoglobulin variable region. The variable regions of the heavy and light chains each contain three CDRs, designated CDR1 , CDR2 and CDR3. The precise boundaries of these CDRs can be defined according to various numbering systems known in the art (see e.g. Dondelinger, M., et al., 2018. Frontiers in immunology, 9, p.2278), such as the Kabat numbering system (Kabat et al., Sequences of Proteins of Immunological Interest, 5th Ed. Public Health Service, National Institutes of Health, Bethesda, Md., 1991 ; Kabat et al., 1992, Sequences of Proteins of Immunological Interest, DIANE Publishing: 2719), the Chothia numbering system (Chothia & Lesk (1987) J. Mol. Biol. 196:901-917; Chothia et al. (1989) Nature 342:878-883) or the IMGT numbering system (Lefranc et al., Dev. Comparat.lmmunol.27:55-77, 2003;

[0260] Ehrenmann F, Kaas Q, Lefranc M P. IMGT / 3Dstructure-DB and IMGT / DomainGapAlign: a database and a tool for immunoglobulins or antibodies, T cell receptors, MHC, IgSF and MhcSF[J], Nucleic acids research, 2009;38(suppl_1):D301-D307). For a given antibody, those skilled in the art will readily identify the CDRs defined by each numbering system. Also, the correspondence between different numbering systems is well known to those skilled in the art (for example, see Lefranc et al., Dev. Comparat. Immunol. 27:55-77, 2003). “Kabat,” as used herein, means an immunoglobulin alignment and numbering system pioneered by Elvin a. Kabat ((1991) Sequences of Proteins of Immunological Interest’ 5th Ed. Public Health Service, National Institutes of Health, Bethesda, Md.). It may be possible to introduce one or more mutations (substitutions, additions or deletions) into each CDR without negatively affecting binding activity. Each CDR may, for example, have one, two or three amino acid mutations.

[0261] “Chimeric antibody” refers to an antibody in which a portion of the heavy and / or light chain is identical with or homologous to corresponding sequences in an antibody derived from a particular species (e.g., human) or belonging to a particular antibody class or subclass, while the remainder of the chain(s) is identical with or homologous to corresponding sequences in an antibody derived from another species (e.g., mouse) or belonging to another antibody class or subclass, as well as fragments of such antibodies, so long as they exhibit the desired biological activity.

[0262] “Human antibody” refers to an antibody that comprises human immunoglobulin protein sequences only. A human antibody may contain murine carbohydrate chains if produced in a mouse, in a mouse cell, or in a hybridoma derived from a mouse cell. Similarly, “mouse antibody” or “rat antibody” refer to an antibody that comprises only mouse or rat immunoglobulin sequences, respectively.

[0263] “Humanized antibody” refers to forms of antibodies that contain sequences from non-human (e.g., murine) antibodies as well as human antibodies. Such antibodies contain minimal sequence derived from non-human immunoglobulin. In general, the humanized antibody will comprise substantially all of at least one, and typically two, variable domains, in which all or substantially all of the hypervariable loops correspond to those of a non-human immunoglobulin and all or substantially all of the framework or FR regions are those of a human immunoglobulin sequence.

[0264] The term "monoclonal antibody" refers to an antibody obtained from a substantially homogeneous population of antibodies. The individual antibodies composing the population may be identical except for possible naturally occurring mutations, which may be present in minor amounts. Monoclonal antibodies are highly specific and target a single antigenic epitope. In contrast, polyclonal antibody preparations typically include a large number of antibodies which are specific for different epitopes. The term “multispecific antibody” refers to antibodies which recognise two or more epitopes located on the same or distinct targets. Formats of multispecific antibodies can be divided into two broad categories: IgG-like antibody formats, with an Fc domain, and non-IgG-like antibody formats, without an Fc domain (see e.g. Elshiaty, M., et al., International Journal of Molecular Sciences, 2021 , 22(11), 5632). Examples of multispecific antibodies include bispecific and trispecific antibodies.

[0265] A “single domain antibody” (sdAb) is an antibody composed of a single variable domain (e.g., heavy chain variable region) composed of antibody fragments. Typically, a single domain antibody, domain antibody or nanobody consists of 4 framework regions and 3 complementarity determining regions, the 4 framework regions are respectively FR1-FR4, and the 3 complementarity determining regions are respectively CDR1 -CDR3. In certain embodiments, the single domain antibody of the present application may have a structure of FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4. These antibodies do not require light chain variable regions to bind antigens with high affinity and specificity. Examples of single-domain antibodies include, but are not limited to, VHH fragments, and VNAR fragments. Compared with antibodies composed of heavy chain and light chain, single domain antibodies have high solubility, high stability to heat, pH, protease and other deforming agents, and only need single-chain expression to facilitate large-scale production. As used herein, the term “framework region” or “FR” residues refers to those amino acid residues in an antibody variable region other than the CDR residues as defined above.

[0266] The antibody-drug conjugate according to the invention comprises an antibody which is trastuzumab.

[0267] Techniques for preparing and using various antibody-based constructs and fragments are well known in the art.

[0268] In some embodiments, the antibody may comprise a heavy chain variable (VH) region and a light chain variable (VL) region. In some embodiments, the antibody may comprise a heavy chain variable (VH) region. In some embodiments, the antibody may comprise a light chain variable (VL) region.

[0269] It will be understood that a VH region may be termed as a VH domain. It will also be understood that a VL region may be termed as a VL domain. “Heavy chain variable region” or “VH” refers to the fragment of the heavy chain of an antigenbinding domain or antibody that contains three CDRs interposed between flanking stretches known as framework regions, which are more highly conserved than the CDRs and form a scaffold to support the CDRs. “Light chain variable region” or “VL” refers to the fragment of the light chain of an antigen-binding domain or antibody that contains three CDRs interposed between framework regions.

[0270] The term "chimeric antibody" generally refers to an antibody obtained by fusing a variable region of a murine antibody and a constant region of a human antibody, which can reduce an immune response induced by the murine antibody. For establishment of a chimeric antibody, a hybridoma secreting murine specific monoclonal antibody can be established, and a variable region gene is cloned from the mouse hybridoma cells; then a constant region gene of human antibody can be cloned as required, and the mouse variable region gene and the human constant region gene are connected to form a chimeric gene; then the chimeric gene is inserted into an expression vector, wherein chimeric antibody molecules can be expressed in a eukaryotic system or a prokaryotic system.

[0271] The term "humanized antibody", also referred to as CDR-grafted antibody, generally refers to an antibody produced by grafting mouse CDR sequences into a human antibody variable region framework, i.e., an antibody produced in a different type of human germline antibody framework sequence. Therefore, the heterogeneous reaction induced by the presence of a large number of mouse protein components in the chimeric antibody can be overcome. Such framework sequences can be obtained from public DNA databases or disclosed references that include germline antibody gene sequences. For example, germline DNA sequences of human heavy and light chain variable region genes can be obtained from the "VBase" human germline sequence database.

[0272] The term "fully humanized antibody", "fully human antibody" or "completely human antibody", which may also be known as "fully humanized monoclonal antibody", may have both humanized variable region and constant region so as to eliminate immunogenicity and toxic side effects. The development of monoclonal antibodies has four stages, namely murine monoclonal antibodies, chimeric monoclonal antibodies, humanized monoclonal antibodies and fully humanized monoclonal antibodies. The antibodies or ligands described herein can be fully humanized monoclonal antibodies. Relevant technologies for the preparation of fully human antibodies may be: human hybridoma technology, EBV-transformed B-lymphocyte technology, phage display technology, transgenic mouse antibody preparation technology, single B-cell antibody preparation technology, and the like. In some embodiments, the sequence of the antibody may be defined using Kabat numbering (Kabat E.A. et al., (1991)).

[0273] Antibodies may be obtained by techniques comprising immunizing an animal with a target antigen and isolating the antibody from serum. Monoclonal antibodies may be made by the hybridoma method first described by Kohler et al., Nature 256:495 (1975), or may be made by recombinant DNA methods (see, e.g., U.S. Pat. No. 4,816,567). The monoclonal antibodies may also be isolated from phage antibody libraries using the techniques described in Clackson et al., Nature 352:624-628 (1991) and Marks et al., J. Mol. Biol. 222:581-597 (1991), for example. The antibody may be a chimeric or humanized antibody.

[0274] The antibody according to the invention may have any binding affinity value. Binding affinity is typically described as the strength of the binding interaction between two molecules, (e.g. between a receptor and its ligand or an antibody and its cognate antigen). Binding affinity may be defined by determining the equilibrium dissociation constant (KD), which is used to measure the strengths of molecular interactions. A lower KD value indicates a higher binding affinity, and vice versa a higher KD value indicates a lower binding affinity.

[0275] Binding affinity (e.g. a KD value) may be quantitatively determined or measured using methods know in the art, such as by surface plasmon resonance (SPR), for example by using the Biacore® system (e.g. Biacore T200). In addition to the equilibrium dissociation constant (KD), the association rate constant (Ka (1 / Ms)), and the dissociation rate constant (Kd (1 / s)) may also be determined.

[0276] Methods for determining binding specificity of an antibody to a particular antigen are known in the art include, but are not limited to, ELISA, western blot, immunohistochemistry, flow cytometry, Forster resonance energy transfer (FRET), phage display libraries, yeast two- hybrid screens, co-immunoprecipitation, bimolecular fluorescence complementation and tandem affinity purification. Binding affinity can also be determined using methods such as fluorescence quenching, isothermal titration calorimetry.

[0277] HER2 ANTIBODY - TRASTUZUMAB

[0278] Human epidermal growth factor receptor 2 (HER2), also known as Receptor tyrosine-protein kinase erbB-2 (ERBB2) or CD340, is known to have a key role in the development and progression of certain types of cancers, such as breast cancer and endometrial cancer. According to the first aspect of the invention, the antibody of the antibody-drug conjugate is trastuzumab. The antibody specifically binds to HER2.

[0279] According to the second aspect according to the invention, the antibody of the antibody-drug conjugate is trastuzumab. The antibody specifically binds to HER2.

[0280] It will be understood that trastuzumab is sold under the brand name Herceptin®. However, within the context of the invention it will be understood that any version of the antibody known as trastuzumab, or a variant thereof, may be used.

[0281] In some embodiments, the antibody may comprise a trastuzumab heavy chain amino acid sequence according to SEQ ID NO: 1 or an amino acid sequence with 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% sequence identity thereto.

[0282] In some embodiments, the antibody may comprise a trastuzumab light chain amino acid sequence according to SEQ ID NO: 2 or an amino acid sequence with 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% sequence identity thereto.

[0283] In some embodiments, the antibody may comprise (i) a trastuzumab heavy chain amino acid sequence according to SEQ ID NO: 1 or an amino acid sequence with 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% sequence identity thereto; and (ii) a trastuzumab light chain amino acid sequence according to SEQ ID NO: 2 or an amino acid sequence with 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% sequence identity thereto.

[0284] In some embodiments, the antibody may comprise a trastuzumab heavy chain amino acid sequence according to SEQ ID NO: 1 and a trastuzumab light chain amino acid sequence according to SEQ ID NO: 2.

[0285] SEQ ID NO: 1 - amino acid sequence of the heavy chain of trastuzumab

[0286] EVQLVESGGGLVQPGGSLRLSCAASGFNIKDTYIHWVRQAPGKGLEWVARIYPTNGYTRY

[0287] ADS VKGRFT I SADT S KNTAYLQMNS LRAEDTAVYYCS RWGGDGFYAMDYWGQGTLVTVS S ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSS GLYSLSSWTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGG PSVFLFPPKPKDTLMI SRTPEVTCVWDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYN STYRWSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTI SKAKGQPREPQVYTLPPSREE MTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRW QQGNVFSCSVMHEALHNHYTQKSLSLSPGK SEQ ID NO: 2 - amino acid sequence of the light chain of trastuzumab

[0288] DIQMTQSPSSLSASVGDRVTITCRASQDVNTAVAWYQQKPGKAPKLLIYSASFLYSGVPS RFSGSRSGTDFTLTISSLQPEDFATYYCQQHYTTPPTFGQGTKVEIKRTVAAPSVFIFPP SDEQLKSGTASWCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLT LSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC

[0289] In some embodiments, the antibody may comprise a trastuzumab heavy chain variable region amino acid sequence according to SEQ ID NO: 3 or an amino acid sequence with 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% sequence identity thereto.

[0290] In some embodiments, the antibody may comprise a trastuzumab light chain variable region amino acid sequence according to SEQ ID NO: 4 or an amino acid sequence with 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% sequence identity thereto.

[0291] In some embodiments, the antibody may comprise (i) a trastuzumab heavy chain variable region amino acid sequence according to SEQ ID NO: 3 or an amino acid sequence with 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% sequence identity thereto; and (ii) a trastuzumab light chain variable region amino acid sequence according to SEQ ID NO: 4 or an amino acid sequence with 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% sequence identity thereto.

[0292] In some embodiments, the antibody may comprise a trastuzumab heavy chain variable region amino acid sequence according to SEQ ID NO: 3 and a trastuzumab light chain amino acid variable region sequence according to SEQ ID NO: 4.

[0293] SEQ ID NO: 3 - amino acid sequence of the heavy chain variable region of trastuzumab

[0294] EVQLVESGGGLVQPGGSLRLSCAASGFNIKDTYIHWVRQAPGKGLEWVARIYPTNGYTRYADSVKGRF TISADTSKNTAYLQMNSLRAEDTAVYYCSRWGGDGFYAMDYWGQGTLVTVSS

[0295] SEQ ID NO: 4 - amino acid sequence of the light chain variable region of trastuzumab

[0296] DIQMTQSPSSLSASVGDRVTITCRASQDVNTAVAWYQQKPGKAPKLLIYSASFLYSGVPSRFSGSRSG TDFTLTISSLQPEDFATYYCQQHYTTPPTFGQGTKVEIK

[0297] In some embodiments, the antibody may comprise the same HCDRs 1-3 as trastuzumab, wherein the HCDR1 may comprise an amino acid sequence set forth in SEQ ID NO: 5, the HCDR2 may comprise an amino acid sequence set forth in SEQ ID NO: 6, and the HCDR3 may comprise an amino acid sequence set forth in SEQ ID NO: 7. The CDRs may be defined according to Kabat. In some embodiments, the antibody may comprise the same LCDRs 1-3 as trastuzumab, wherein the LCDR1 may comprise an amino acid sequence set forth in SEQ ID NO: 8, the LCDR2 may comprise an amino acid sequence set forth in SEQ ID NO: 9, and the LCDR3 may comprise an amino acid sequence set forth in SEQ ID NO: 10. The CDRs may be defined according to Kabat.

[0298] In some embodiments, the antibody may comprise the same LCDRs 1-3 and HCDRs as trastuzumab, wherein the LCDR1 may comprise an amino acid sequence set forth in SEQ ID NO: 5, the LCDR2 may comprise an amino acid sequence set forth in SEQ ID NO: 6, the LCDR3 may comprise an amino acid sequence set forth in SEQ ID NO: 7, the HCDR1 may comprise an amino acid sequence set forth in SEQ ID NO: 8, the HCDR2 may comprise an amino acid sequence set forth in SEQ ID NO: 9, and the HCDR3 may comprise an amino acid sequence set forth in SEQ ID NO: 10. The CDRs may be defined according to Kabat.

[0299] SEQ ID NO: 5 - amino acid sequence of HCDR1 of trastuzumab

[0300] DTYIH

[0301] SEQ ID NO: 6 - amino acid sequence of HCDR2 of trastuzumab

[0302] RIYPTNGYTRYADSVK

[0303] SEQ ID NO: 7 - amino acid sequence of HCDR3 of trastuzumab

[0304] SRWGGDGFYAMDY

[0305] SEQ ID NO: 8 - amino acid sequence of LCDR1 of trastuzumab

[0306] RASQDVNTAVA

[0307] SEQ ID NO: 9 - amino acid sequence of LCDR2 of trastuzumab

[0308] SAS FLYS

[0309] SEQ ID NO: 10 - amino acid sequence of LCDR3 of trastuzumab

[0310] QQHYTTPPT

[0311] LINKER

[0312] The moiety of the antibody-drug conjugate of formula (I) above comprises a linker L, which is a chemical structural fragment, which is linked to the antibody trastuzumab at one end and linked to a cytotoxic drug at the other end, or linked to other linkers and then linked to the cytotoxic drug. The direct or indirect linking of a ligand may mean that the group is directly linked to the ligand via a covalent bond, and may also be linked to the ligand via a linker structure.

[0313] The linker structure is a structure shown as -La-Lb-Lc- as defined herein.

[0314] DRUG / PAYLOAD

[0315] The moiety of the antibody-drug conjugate of formula (I) above contains a drug linked to the antibody trastuzumab Ab via linker L. The remaining moieties of the antibody-drug conjugate, i.e. all those structures including L2and all structures to the right of it in formula (I), are termed “the drug moiety” or “the payload moiety”. In use, the bond between L and L2is cleaved, and L2and all structures to the right of it are released in vivo.

[0316] In some embodiments, X1is saturated C.

[0317] In some embodiments, ring A is 3-10 membered saturated carbocyclyl.

[0318] In some embodiments, ring A is 3-6 membered saturated carbocyclyl.

[0319] In some embodiments, ring A is a 4 membered saturated carbocyclyl.

[0320] In some embodiments, ring A is c / s-1 ,3-cyclobutyl.

[0321] In some embodiments, ring A is substituted with 0 substituent R1a.

[0322] In some embodiments, n is 1 , and L1is -C(R5a)(R5b)-.

[0323] In some embodiments, 1 methylene unit of L1is replaced by -N(R6)C(O)-, -C(O)N(R6)-, -C(O)- , -OC(O)-, -C(O)O-, -NR6-, -O-, -S-, -SO-, -SO2-, -P(R6)-, -P(=O)(R6)-, -N(R6)SO2-, -SO2N(R6)- , -C(=S)-, -C(=NR6)-, -N=N-, -C=N-, -N=C- or -C(=N2)-.

[0324] In some embodiments, 1 methylene unit of L1is replaced by -C(O)-.

[0325] In some embodiments, n is 1 , and 1 methylene unit of L1is replaced by -C(O)-.

[0326] In some embodiments, R2is selected from the group consisting of: -O-, -(R2a)N- and -S-. In some embodiments, R2is -O-.

[0327] In some embodiments, p is 1.

[0328] In some embodiments, R1ais H.

[0329] In some embodiments, R1bis H.

[0330] In some embodiments, R2ais H.

[0331] In some embodiments, R3aand R3bare each independently H.

[0332] In some embodiments, R4is H.

[0333] In some embodiments, R5aand R5bare each independently H.

[0334] In some embodiments, R6is H.

[0335] In some embodiments, Rnis H.

[0336] In some embodiments, R is H.

[0337] In some embodiments, Rais H.

[0338] In some embodiments, Rbis H.

[0339] In some embodiments, ring A is substituted with 1 L2.

[0340] In some embodiments, m is 0, and L3is a covalent bond.

[0341] In some embodiments, n is 1 , and L1is -C(R5a)(R5b)- wherein 1 methylene unit of L1may be replaced by -C(O)-.

[0342] In some embodiments, the drug moiety may have the following partial structure l-A: wherein R2is as defined above, either in its broadest aspect or a preferred aspect.

[0343] In some embodiments, the drug moiety is Compound 2, having the following structure:

[0344] Compound 2 is disclosed as compound P-ll-3 and general and specific methods for its synthesis are disclosed in WO2022 / 068878 and published national applications derived therefrom.

[0345] DOSE

[0346] In the first aspect of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at any dose.

[0347] In some embodiments of the first aspect of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose in the range of 2.2 mg / kg to 12.0 mg / kg. In these embodiments or any embodiments herein, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is preferably Compound 1 or a pharmaceutically acceptable salt thereof. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.5 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.6 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be selected from the group of integers or decimals of about: 7.0, 7.1 , 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0.

[0348] In some embodiments of the first aspect of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose in the range of 6.0 mg / kg to 10.0 mg / kg. In these embodiments or any embodiments herein, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is preferably Compound 1 or a pharmaceutically acceptable salt thereof. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.5 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.6 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be selected from the group of integers or decimals of about: 7.0, 7.1 , 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0.

[0349] In the second aspect of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is administered to a patient at a dose in the range of 2.2 mg / kg to 12.0 mg / kg. In these embodiments, the antibody-drug conjugate is preferably Compound 1 or a pharmaceutically acceptable salt thereof. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.5 to about 8. In some embodiments, the antibody-drug conjugate is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.6 to about 8. In some embodiments, the antibody-drug conjugate is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be selected from the group of integers or decimals of about: 7.0, 7.1 , 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0.

[0350] In some embodiments of the second aspect of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 6.0 mg / kg to 10.0 mg / kg. In these embodiments or any embodiments herein, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is preferably Compound 1 or a pharmaceutically acceptable salt thereof. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.5 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.6 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be selected from the group of integers or decimals of about: 7.0, 7.1 , 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0.

[0351] In some embodiments of the third aspect of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 6.0 mg / kg to 10.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 6.5 mg / kg to 9.5 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 7.0 mg / kg to 9.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 7.5 mg / kg to 8.5 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 7.8 mg / kg to 8.2 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose of about 8.0 mg / kg. In these embodiments or any embodiments herein, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is preferably Compound 1 or a pharmaceutically acceptable salt thereof. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.5 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.6 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be selected from the group of integers or decimals of about: 7.0, 7.1 , 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0.

[0352] In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 2.0 mg / kg to 12.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 2.5 mg / kg to 11.5 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 3.0 mg / kg to 11.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 3.5 mg / kg to 10.5 mg / kg. In each of these embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is preferably Compound 1 or a pharmaceutically acceptable salt thereof. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.5 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.6 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be selected from the group of integers or decimals of about: 7.0, 7.1 , 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0.

[0353] In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 4.0 mg / kg to 10.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 4.5 mg / kg to 9.5 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 5.0 mg / kg to 9.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 5.5 mg / kg to 8.5 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 6.0 mg / kg to 8.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 6.5 mg / kg to 7.5 mg / kg. In each of these embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is preferably Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.5 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.6 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or pharmaceutically acceptable salt thereof, and the average connection number Namay be selected from the group of integers or decimals of about: 7.0, 7.1 , 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0.

[0354] In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 2.0 mg / kg to 3.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 3.0 mg / kg to 4.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 4.0 mg / kg to 5.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 5.0 mg / kg to 6.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 6.0 mg / kg to 7.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 7.0 mg / kg to 8.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 8.0 mg / kg to 9.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 9.0 mg / kg to 10.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 10.0 mg / kg to 11.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 11.0 mg / kg to 12.0 mg / kg. In each of these embodiments, the antibody-drug conjugate or a pharmaceutically acceptable salt thereof is preferably Compound 1 or a pharmaceutically acceptable salt thereof. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.5 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.6 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be selected from the group of integers or decimals of about: 7.0, 7.1 , 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 2.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 2.1 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 2.2 mg / kg. In some embodiments, the antibodydrug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of

[0355] 2.3 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 2.4 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 2.5 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 2.6 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 2.7 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 2.8 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 2.9 mg / kg. In each of these embodiments, the antibodydrug conjugate or pharmaceutically acceptable salt thereof is preferably Compound 1 or a pharmaceutically acceptable salt thereof. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.5 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.6 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be selected from the group of integers or decimals of about: 7.0, 7.1 , 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0.

[0356] In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 3.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 3.5 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 4.0 mg / kg. In some embodiments, the antibodydrug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of

[0357] 4.4 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 4.5 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 5.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 5.5 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 6.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 6.5 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 7.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 7.5 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 8.0 mg / kg. In some embodiments, the antibodydrug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 8.5 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 9.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 9.5 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 10.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 10.5 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 11 .0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 11 .5 mg / kg. In some embodiments, the antibodydrug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 12.0 mg / kg. In each of these embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is preferably Compound 1 or a pharmaceutically acceptable salt thereof. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.5 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.6 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be selected from the group of integers or decimals of about: 7.0, 7.1 , 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0.

[0358] In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 6.5 mg / kg to 9.5 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 7.0 mg / kg to 9.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 7.5 mg / kg to 8.5 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 7.0 mg / kg to 8.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a patient at a dose in the range of 8.0 mg / kg to 9.0 mg / kg. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a dose of 8.0 mg / kg. In each of these embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is preferably Compound 1 or a pharmaceutically acceptable salt thereof. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.5 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.6 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be selected from the group of integers or decimals of about: 7.0, 7.1 , 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0.

[0359] Preferably, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is administered to a patient at a dose in the range of 6.0 mg / kg to 8.0 mg / kg, more preferably about 6, about 7 or about 8 mg / kg.

[0360] In some embodiments of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered over a number of treatment cycles (as defined herein). In each treatment cycle, the period over which the antibody-drug conjugate or pharmaceutically acceptable salt thereof is administered is preferably 30 minutes to 3 hours, more preferably 40 minutes to 2 hours, more preferably 60 to 90 minutes, and the rest period is preferably 7 to 35 days, more preferably 14 to 28 days, even more preferably 18 to 23 days, most preferably 21 days.

[0361] In some embodiments of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered in at least 1 treatment cycle. In some embodiments of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered in at least 2 treatment cycles. In some embodiments of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered in at least 3 treatment cycles. In some embodiments of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered in at least 4 treatment cycles. In some embodiments of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered in at least 5 treatment cycles. In some embodiments of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered in at least 6 treatment cycles. In some embodiments of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered in at least 7 treatment cycles. In some embodiments of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered in at least 8 treatment cycles. In some embodiments of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered in at least 9 treatment cycles. In some embodiments of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered in at least 10 treatment cycles. In some embodiments of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered in at least 11 treatment cycles. In some embodiments of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered in at least 12 treatment cycles. In some embodiments of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered in at least 13 treatment cycles. In some embodiments of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered in at least 14 treatment cycles. In these embodiments, the antibody-drug conjugate is preferably administered once every 3 weeks. In these embodiments, the antibody-drug conjugate is preferably Compound 1 or a pharmaceutically acceptable salt thereof. In some embodiments, the antibody-drug conjugate is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.5 to about 8. In some embodiments, the antibody-drug conjugate is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.6 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be selected from the group of integers or decimals of about: 7.0, 7.1 , 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0.

[0362] In some embodiments of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered in from 2 to 14 treatment cycles. In some embodiments of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered in from 3 to 13 treatment cycles. In some embodiments of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered in from 4 to 12 treatment cycles. In some embodiments of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered in from 5 to 11 treatment cycles. In some embodiments of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered in from 6 to 10 treatment cycles. In some embodiments of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered in from 7 to 9 treatment cycles. In some embodiments of the invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered in 8 treatment cycles. In these embodiments, the antibody-drug conjugate is preferably administered once every 3 weeks. In these embodiments, the antibody-drug conjugate is preferably Compound 1 or a pharmaceutically acceptable salt thereof. In some embodiments, the antibody-drug conjugate is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.5 to about 8. In some embodiments, the antibody-drug conjugate is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.6 to about 8. In some embodiments, the antibody-drug conjugate is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be selected from the group of integers or decimals of about: 7.0, 7.1 , 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0.

[0363] It will be understood that the dose should be selected based on considerations of age, body weight, disease symptoms, disease progression and / or severity, sex, and / or any other factors which may interfere with the therapeutic effects the antibody-drug conjugate or pharmaceutically acceptable salt thereof according to the invention.

[0364] ADMINISTRATION

[0365] In some embodiments, the form of administration of the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be, for example, in a form suitable for oral, parenteral, intraperitoneal, systemic, intravenous (such as intravenous infusion or intravenous drip), intramuscular, subcutaneous, topical, inhalative, rectal, sublingual, transdermal, or vaginal administration.

[0366] In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered intravenously (e.g. by being injected into a subject). In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a subject once (i.e. as a one-off treatment). For example, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a subject once over a continuous period of hours or days.

[0367] In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a subject on multiple, separate occasions (e.g. as part of an on-going treatment). For example, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered to a subject on multiple, separate occasions over a total period of hours, days, weeks, months or years.

[0368] In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered once every day. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered more than once every day.

[0369] In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered once every week. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered more than once every week.

[0370] In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered once every two weeks. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered more than once every two weeks.

[0371] In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered once every three weeks. In some embodiments, the antibodydrug conjugate or pharmaceutically acceptable salt thereof may be administered more than once every three weeks.

[0372] In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered once every four weeks. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered more than once every four weeks. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered once every five weeks. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered more than once every five weeks.

[0373] In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered once every six weeks. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered more than once every six weeks.

[0374] In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered once every month. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered more than once every month.

[0375] In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered once every year. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered more than once every year.

[0376] PHARMACEUTICAL COMPOSITION

[0377] The present invention provides a pharmaceutical composition comprising the antibody-drug conjugate or pharmaceutically acceptable salt thereof according to the invention. In this specification the terms “pharmaceutical composition” and “formulation” are synonymous.

[0378] In some embodiments, the pharmaceutical composition may further comprise a pharmaceutically acceptable carrier, diluent, excipient or adjuvant, salt, and optionally one or more further pharmaceutically active polypeptides and / or compounds.

[0379] In some embodiments, the pharmaceutical composition according to the invention may comprise one or more compounds, components and / or active agents, in addition to the antibody-drug conjugate or pharmaceutically acceptable salt thereof according to the invention.

[0380] Depending on the method of administration, in some embodiments the composition may contain 0.1 wt.% to 99% wt.% of the active compound (i.e. the antibody-drug conjugate or pharmaceutically acceptable salt thereof according to the invention). In some embodiments, the composition may contain 0.1 , 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 , 12, 13, 14, 15, 16, 17, 18, 19, 20, 21 , 22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34,

[0381] 35, 36, 37, 38, 39, 40, 41 , 42, 43, 44, 45, 46, 47, 48, 49, 50, 51 , 52, 53, 54, 55, 56, 57, 58, 59,

[0382] 60, 61 , 62, 63, 64, 65, 66, 67, 68, 69, 70, 71 , 72, 73, 74, 75, 76, 77, 78, 79, 80, 81 , 82, 83, 84,

[0383] 85, 86, 87, 88, 89, 90, 91 , 92, 93, 94, 95, 96, 97, 98, or 99 wt.% of the antibody-drug conjugate or pharmaceutically acceptable salt thereof according to the invention.

[0384] Pharmaceutical compositions typically should be sterile and stable under the conditions of manufacture and storage. The pharmaceutical composition according to the invention may be produced using current good manufacturing practices (CGMP).

[0385] The term “pharmaceutical composition” as used herein refers to a substance and / or a combination of substances that can be used for the identification, prevention or treatment of a tissue status or disease. The pharmaceutical composition may be formulated to be suitable for administration to a patient in order to prevent and / or treat disease. Further a pharmaceutical composition may refer to the combination of an active agent with a carrier, inert or active, making the composition suitable for therapeutic use. Pharmaceutical compositions can be formulated for oral, parenteral, topical, inhalative, rectal, sublingual, transdermal, subcutaneous or vaginal application routes according to their chemical and physical properties.

[0386] Pharmaceutical compositions may comprise solid, semisolid, liquid, transdermal therapeutic systems (TTS). Solid compositions are selected from the group consisting of tablets, coated tablets, powder, granulate, pellets, capsules, effervescent tablets or transdermal therapeutic systems. Also comprised are liquid compositions, selected from the group consisting of solutions, syrups, infusions, extracts, solutions for intravenous application, solutions for infusion or solutions of the carrier systems of the present invention. Semisolid compositions that can be used in the context of the invention comprise emulsion, suspension, creams, lotions, gels, globules, buccal tablets and suppositories.

[0387] The term “carrier”, as used herein, refers to a diluent, adjuvant, excipient, or vehicle with which the therapeutic agent is administered. Such pharmaceutical carriers can be sterile liquids, such as saline solutions in water and oils, including those of petroleum, animal, vegetable or synthetic origin, such as peanut oil, soybean oil, mineral oil, sesame oil and the like.

[0388] A sterile saline solution is a preferred carrier when the pharmaceutical composition is administered intravenously. Saline solutions and aqueous dextrose and glycerol solutions can also be employed as liquid carriers, particularly for injectable solutions. Suitable pharmaceutical excipients include starch, glucose, lactose, sucrose, gelatin, malt, rice, flour, chalk, silica gel, sodium stearate, glycerol monostearate, talc, sodium chloride, dried skim milk, glycerol, propylene, glycol, water, ethanol and the like.

[0389] The composition, if desired, can also contain minor amounts of wetting or emulsifying agents, or pH buffering agents. These compositions can take the form of solutions, suspensions, emulsions, tablets, pills, capsules, powders, sustained-release compositions and the like. The composition can be formulated as a suppository, with traditional binders and carriers such as triglycerides. The compounds of the invention can be formulated as neutral or salt forms. Pharmaceutically acceptable salts include those formed with free amino groups such as those derived from hydrochloric, phosphoric, acetic, oxalic, tartaric acids, etc., and those formed with free carboxyl groups such as those derived from sodium, potassium, ammonium, calcium, ferric hydroxides, isopropylamine, triethylamine, 2-ethylaminoethanol, histidine, procaine, etc. Examples of suitable pharmaceutical carriers are described in "Remington's Pharmaceutical Sciences" by E. W. Martin. Such compositions will contain a therapeutically effective amount of the compound, preferably in purified form, together with a suitable amount of carrier so as to provide the form for proper administration to the patient. The composition should suit the mode of administration.

[0390] In some embodiments, the salt may comprise a metal cation, such as a sodium salt or a potassium salt.

[0391] In some embodiments, the pharmaceutical composition may comprise an aqueous diluent or solvent. In some embodiments, the aqueous diluent or solvent may be a phosphate buffered saline solution, such as a sterile phosphate buffered saline solution.

[0392] In some embodiments, the pharmaceutical composition may be in a form suitable for intravenous infusion. In some embodiments, the pharmaceutical composition may be administered intravenously.

[0393] In some embodiments, the antibody-drug conjugate according to the invention may be formulated as a composition, such as a pharmaceutical composition as described herein. In some embodiments, the composition may comprise the antibody-drug conjugate according to the invention at a concentration of 1 to 100 mg / ml. In some embodiments, the composition may comprise the antibody-drug conjugate according to the invention at a concentration of 10- 50 mg / ml. In some embodiments, the composition may comprise the antibody-drug conjugate according to the invention at a concentration of 10-30 mg / ml. In some embodiments, the composition may comprise the antibody-drug conjugate according to the invention at a concentration of 30-50 mg / ml. In some embodiments, the composition may comprise the antibody-drug conjugate according to the invention at a concentration of 15-25 mg / ml. In some embodiments, the composition may comprise the antibody-drug conjugate according to the invention at a concentration of 17.5-22.5 mg / ml. In some embodiments, the composition may comprise the antibody-drug conjugate according to the invention at a concentration of about 20 mg / ml.

[0394] In some embodiments, the composition also contains histidine, a pharmaceutically acceptable salt thereof, or a pharmaceutically acceptable solvate of either thereof. In one embodiment, the histidine is L-histidine, a pharmaceutically acceptable salt thereof, or a pharmaceutically acceptable solvate of either thereof. In one embodiment, the histidine is free base. In one embodiment, the histidine is L-histidine free base. In one embodiment, the histidine is histidine hydrochloride monohydrate. In one embodiment, the histidine is L-histidine hydrochloride monohydrate.

[0395] In some embodiments, the composition also contains a histidine buffer. In this specification the term “histidine buffer” takes its normal meaning in the art of a solution containing histidine and a pharmaceutically acceptable acid addition salt thereof containing its conjugate acid, the precise amounts of each depending on the pH. In one embodiment, the histidine is L-histidine.

[0396] The counter-ion in the pharmaceutically acceptable salt of histidine may be formed from any pharmaceutically acceptable acid, examples of which include inorganic acids such as hydrohalic (hydrofluoric, hydrochloric, hydrobromic, hydriodic), nitric, sulphuric or phosphoric acids, and organic acids such as acetic, citric, succinic or tartaric acid. Preferably the pharmaceutically acceptable salt is a hydrohalide salt, more preferably the hydrochloride. The pharmaceutically acceptable salt may be provided to the composition in the form of a solvate thereof, such as a hydrate, preferably a monohydrate.

[0397] In some embodiments, the composition may comprise about 1 to about 8 mg / mL total histidine. In some embodiments, the composition may comprise about 2 to about 5 mg / mL histidine. In some embodiments, the composition may comprise about 3.5 to about 4.5 mg / mL total histidine. In some embodiments, the composition may comprise about 3.88 mg / mL total histidine. In these embodiments, the amount of histidine is expressed as the total amount of histidine in the composition including the free base and the histidine component of any pharmaceutically acceptable salt thereof present in the composition.

[0398] In some embodiments, the composition may comprise histidine free base. In some embodiments, the composition may comprise about 0.1 to about 4 mg / ml histidine free base. In some embodiments the composition may comprise about 0.2 to about 2 mg / ml free base. In some embodiments, the composition may comprise about 0.4 to about 1.6 mg / ml histidine free base. In some embodiments, the composition may comprise about 0.6 to about 1 mg / ml histidine free base. In some embodiments, the composition may comprise about 0.82 mg / ml histidine free base.

[0399] In some embodiments, the composition may comprise histidine hydrochloride monohydrate. In some embodiments, the composition may comprise about 0.5 to about 20 mg / ml histidine hydrochloride monohydrate. In some embodiments, the composition may comprise about 1 to about 10 mg / ml histidine hydrochloride monohydrate. In some embodiments, the composition may comprise about 2 to about 8 mg / ml histidine hydrochloride monohydrate. In some embodiments, the composition may comprise about 3 to about 5 mg / ml histidine hydrochloride monohydrate. In some embodiments, the composition may comprise about 4.14 mg / mL histidine hydrochloride monohydrate.

[0400] In some embodiments, the composition may comprise 1 to 100 mM histidine or a pharmaceutically acceptable salt thereof. In some embodiments, the composition may comprise 10-50 mM histidine or a pharmaceutically acceptable salt thereof. In some embodiments, the composition may comprise 10-20 mM histidine or a pharmaceutically acceptable salt thereof. In some embodiments, the composition may comprise 20-30 mg / ml histidine ora pharmaceutically acceptable salt thereof. In some embodiments, the composition may comprise 30-50 mM histidine or a pharmaceutically acceptable salt thereof. In some embodiments, the composition may comprise about 10 mM histidine or a pharmaceutically acceptable salt thereof. In some embodiments, the composition may comprise about 20 mM histidine ora pharmaceutically acceptable salt thereof. In some embodiments, the composition may comprise about 25 mM histidine or a pharmaceutically acceptable salt thereof. In some embodiments, the composition may comprise about 30 mM histidine or a pharmaceutically acceptable salt thereof. In these embodiments, the concentration of histidine is expressed as the total concentration of histidine in the composition including the free base and the histidine component of any pharmaceutically acceptable salt thereof present in the composition. In some embodiments, the composition also contains sucrose. In some embodiments, the composition may comprise about 20 to about 160 mg / ml sucrose. In some embodiments, the composition may comprise about 40 to about 140 mg / ml sucrose. In some embodiments, the composition may comprise about 60 to about 120 mg / ml sucrose. In some embodiments, the composition may comprise about 80 to about 100 mg / ml sucrose. In some embodiments, the composition may comprise about 90 mg / ml sucrose.

[0401] In some embodiments, the composition may comprise 1 to 20% (w / v) sucrose. In some embodiments, the composition may comprise 5-10 % (w / v) sucrose. In some embodiments, the composition may comprise 8-10 % (w / v) sucrose. In some embodiments, the composition may comprise about 5% (w / v) sucrose. In some embodiments, the composition may comprise about 6% (w / v) sucrose. In some embodiments, the composition may comprise about 7% (w / v) sucrose. In some embodiments, the composition may comprise about 8% (w / v) sucrose. In some embodiments, the composition may comprise about 9% (w / v) sucrose. In some embodiments, the composition may comprise about 10 % (w / v) sucrose.

[0402] In some embodiments, the composition also contains polysorbate 80. In some embodiments, the composition may comprise about 0.1 to about 0.5 mg / ml polysorbate 80. In some embodiments, the composition may comprise about 0.2 to about 0.4 mg / ml polysorbate 80. In some embodiments, the composition may comprise about 0.25 to about 0.35 mg / ml polysorbate 80. In some embodiments, the composition may comprise about 0.3 mg / l polysorbate 80.

[0403] In some embodiments, the composition may comprise 0.01 to 0.5 % (w / v) polysorbate 80. In some embodiments, the composition may comprise 0.05-0.1 % (w / v) polysorbate 80. In some embodiments, the composition may comprise 0.01-0.05% (w / v) polysorbate 80. In some embodiments, the composition may comprise 0.015-0.045% (w / v) polysorbate 80. In some embodiments, the composition may comprise about 0.02% (w / v) polysorbate 80. In some embodiments, the composition may comprise about 0.03% (w / v) polysorbate 80.

[0404] In some embodiments, the pH of the composition may be 5 to 8. In some embodiments, the pH of the composition may be 5 to 7. In some embodiments, the pH of the composition may be 5 to 6. In some embodiments, the pH of the composition may be 5.3 to 5.7. In some embodiments, the pH of the composition may be about 5.5. In some embodiments, the antibody-drug conjugate according to the invention may be formulated as a composition comprising: about 20mg / ml antibody-drug conjugate according to the invention; about 25 mM histidine or a pharmaceutically acceptable salt thereof; about 9% (w / v) sucrose; and about 0.03% (w / v) polysorbate 80, and the pH of the composition may be about 5.5.

[0405] This composition is referred to below as “Composition 1”.

[0406] The present invention also provides a composition, typically an aqueous composition, comprising: about 20mg / ml of an antibody-drug conjugate according to the first or second aspect of the invention; about 25 mM histidine or a pharmaceutically acceptable salt thereof; about 9% (w / v) sucrose; and about 0.03% (w / v) polysorbate 80, wherein the pH of the composition is about 5.5.

[0407] The present invention also provides a composition, typically an aqueous composition, comprising: about 20mg / ml of an antibody-drug conjugate according to the first or second aspect of the invention; about 0.82 mg / ml L-histidine; about 4.14 mg / ml L-histidine hydrochloride monohydrate; about 90 mg / ml sucrose; and about 0.3 mg / ml polysorbate 80.

[0408] In some embodiments, the antibody-drug conjugate according to the invention may be formulated as a lyophilized composition, such as a lyophilized powder composition.

[0409] In some embodiments, the lyophilized composition may comprise the antibody-drug conjugate according to the invention in an amount of about 5 to about 500 mg. In some embodiments, the lyophilized composition may comprise the antibody-drug conjugate according to the invention in an amount of about 50 to about 250 mg. In some embodiments, the lyophilized composition may comprise the antibody-drug conjugate according to the invention in an amount of about 50 to about 150 mg. In some embodiments, the lyophilized composition may comprise the antibody-drug conjugate according to the invention in an amount of about 75 to about 125 mg. In some embodiments, the lyophilized composition may comprise the antibodydrug conjugate according to the invention in an amount of about 90 to about 110 mg. In some embodiments, the lyophilized composition may comprise the antibody-drug conjugate according to the invention in an amount of about 100 mg.

[0410] In some embodiments, the lyophilized composition may comprise histidine. In some embodiments, the lyophilized composition may comprise about 5 to about 40 mg total histidine. In some embodiments, the composition may comprise about 10 to about 30 mg histidine. In some embodiments, the lyophilized composition may comprise about 15 to about 25 mg total histidine. In some embodiments, the lyophilized composition may comprise about 18 to about 22 mg total histidine. In some embodiments, the lyophilized composition may comprise about 19.42 mg total histidine. In these embodiments, the amount of histidine is expressed as the total amount of histidine in the composition including the free base and the histidine component of any pharmaceutically acceptable salt thereof present in the composition.

[0411] In some embodiments, the lyophilized composition may comprise histidine free base. In some embodiments, the lyophilized composition may comprise about 0.5 to about 20 mg histidine free base. In some embodiments, the lyophilized composition may comprise about 1 to about 10 mg histidine free base. In some embodiments, the lyophilized composition may comprise about 2 to about 8 mg histidine free base. In some embodiments, the lyophilized composition may comprise about 3 to about 5 mg histidine free base. In some embodiments, the lyophilized composition may comprise about 4.1 mg histidine free base.

[0412] In some embodiments, the lyophilized composition may comprise about 0.5 to about 20 parts by weight histidine free base, relative to 100 parts by weight of the antibody-drug conjugate. In some embodiments, the lyophilized composition may comprise about 1 to about 10 parts by weight histidine free base, relative to 100 parts by weight of the antibody-drug conjugate. In some embodiments, the lyophilized composition may comprise about 2 to about 8 parts by weight histidine free base, relative to 100 parts by weight of the antibody-drug conjugate. In some embodiments, the lyophilized composition may comprise about 3 to about 5 parts by weight histidine free base, relative to 100 parts by weight of the antibody-drug conjugate. In some embodiments, the lyophilized composition may comprise about 4.1 mg parts by weight histidine free base, relative to 100 parts by weight of the antibody-drug conjugate.

[0413] In some embodiments, the lyophilized composition may comprise histidine hydrochloride monohydrate. In some embodiments, the lyophilized composition may comprise about 2.5 to about 100 mg histidine hydrochloride monohydrate. In some embodiments, the lyophilized composition may comprise about 5 to about 50 mg histidine hydrochloride monohydrate. In some embodiments, the lyophilized composition may comprise about 10 to about 40 mg histidine hydrochloride monohydrate. In some embodiments, the lyophilized composition may comprise about 15 to about 25 mg histidine hydrochloride monohydrate. In some embodiments, the lyophilized composition may comprise about 20.7 mg histidine hydrochloride monohydrate.

[0414] In some embodiments, the lyophilized composition may comprise about 2.5 to about 100 parts by weight histidine hydrochloride monohydrate relative to 100 parts by weight of the antibodydrug conjugate. In some embodiments, the lyophilized composition may comprise about 5 to about 50 parts by weight histidine hydrochloride monohydrate relative to 100 parts by weight of the antibody-drug conjugate. In some embodiments, the lyophilized composition may comprise about 10 to about 40 parts by weight histidine hydrochloride monohydrate relative to 100 parts by weight of the antibody-drug conjugate. In some embodiments, the lyophilized composition may comprise about 15 to about 25 parts by weight histidine hydrochloride monohydrate relative to 100 parts by weight of the antibody-drug conjugate. In some embodiments, the lyophilized composition may comprise about 20.7 parts by weight histidine hydrochloride monohydrate relative to 100 parts by weight of the antibody-drug conjugate.

[0415] In some embodiments, the lyophilized composition may comprise sucrose. In some embodiments, the lyophilized composition may comprise about 100 to about 800 mg sucrose. In some embodiments, the lyophilized composition may comprise about 200 to about 700 mg sucrose. In some embodiments, the lyophilized composition may comprise about 300 to about 600 mg sucrose. In some embodiments, the lyophilized composition may comprise about 400 to about 500 mg sucrose. In some embodiments, the composition may comprise about 450 mg sucrose.

[0416] In some embodiments, the lyophilized composition may comprise about 100 to about 800 parts by weight sucrose relative to 100 parts by weight of the antibody-drug conjugate. In some embodiments, the lyophilized composition may comprise about 200 to about 700 parts by weight sucrose relative to 100 parts by weight of the antibody-drug conjugate. In some embodiments, the lyophilized composition may comprise about 300 to about 600 parts by weight sucrose relative to 100 parts by weight of the antibody-drug conjugate. In some embodiments, the lyophilized composition may comprise about 400 to about 500 parts by weight sucrose relative to 100 parts by weight of the antibody-drug conjugate. In some embodiments, the composition may comprise about 450 parts by weight sucrose relative to 100 parts by weight of the antibody-drug conjugate.

[0417] In some embodiments, the lyophilized composition may comprise polysorbate 80. In some embodiments, the lyophilized composition may comprise about 0.5 to about 2.5 mg polysorbate 80. In some embodiments, the lyophilized composition may comprise about 1 to about 2 mg polysorbate 80. In some embodiments, the lyophilized composition may comprise about 1 .3 to about 1 .7 mg polysorbate 80. In some embodiments, the lyophilized composition may comprise about 1 .5 mg polysorbate 80.

[0418] In some embodiments, the lyophilized composition may comprise about 0.5 to about 2.5 parts by weight polysorbate 80 relative to 100 parts by weight of the antibody-drug conjugate. In some embodiments, the lyophilized composition may comprise about 1 to about 2 parts by weight polysorbate 80 relative to 100 parts by weight of the antibody-drug conjugate. In some embodiments, the lyophilized composition may comprise about 1.3 to about 1.7 parts by weight polysorbate 80 relative to 100 parts by weight of the antibody-drug conjugate. In some embodiments, the lyophilized composition may comprise about 1.5 parts by weight polysorbate 80 relative to 100 parts by weight of the antibody-drug conjugate.

[0419] In one embodiment, there is provided a lyophilized composition, typically a lyophilized powder composition, comprising:

[0420] (a) about 100mg of an antibody-drug conjugate as defined herein;

[0421] (b) about 4.1 mg L-histidine;

[0422] (c) about 20.7 mg L-histidine hydrochloride monohydrate;

[0423] (d) about 450 mg sucrose; and

[0424] (e) about 1 .5 mg polysorbate 80.

[0425] In one embodiment, there is provided a lyophilized composition, typically a lyophilized powder composition, comprising:

[0426] (a) an antibody-drug conjugate as defined herein, in an amount of about 100 parts by weight;

[0427] (b) L-histidine, in an amount of about 4.1 parts by weight, relative to 100 parts by weight (a);

[0428] (c) L-histidine hydrochloride monohydrate; in an amount of about 20.7 parts by weight, relative to 100 parts by weight (a);

[0429] (d) sucrose, in an amount of about 450 parts by weight, relative to 100 parts by weight (a); and

[0430] (e) polysorbate 80, in an amount of about 1.5 parts by weight, relative to 100 parts by weight (a).

[0431] There is also provided a method of preparing the composition as defined herein, the method comprising reconstituting the lyophilized composition as defined herein with a diluent. In one embodiment the diluent is water. In one embodiment, the water is substantially free of impurities.

[0432] In one embodiment, the water comprises purified water. As is known to the person skilled in the art, purified water is water that has been mechanically filtered or processed to remove impurities. Typical processes used to purify water include distillation, deionization, vapour compression, reverse osmosis, carbon filtering, microfiltration, ultrafiltration, ultraviolet oxidation, or electrodeionization. Combinations of a number of these processes can be used to produce ultrapure water, as defined generally herein.

[0433] Typical impurities that may need to be removed in order to purify water include inorganic ions (typically monitored as electrical conductivity or resistivity or specific tests), organic compounds (typically monitored as TOC or by specific tests), bacteria (typically monitored by total viable counts or epifluorescence), endotoxins and nucleases (typically monitored by LAL or specific enzyme tests), particulates (typically controlled by filtration) and gases (typically managed by degassing when required).

[0434] In one embodiment, the water comprises Water for Injection (WFI). In one embodiment, the water consists essentially of Water for Injection (WFI). In one embodiment, the water consists of Water for Injection (WFI). As is known to the person skilled in the art, Water for Injection (WFI) is sterile, hypotonic, non-pyrogenic, and contains no bacteriostatic or antimicrobial agents. Water for injection is described in the European Pharmacopoeia (Ph. Eur.) 11.4, monograph no. 0169 and in US Pharmacopoeia (USP) monograph no. 1231 “Water for Pharmaceutical Purposes”, incorporated herein by reference.

[0435] In one embodiment, the water comprises water having an equivalent or higher level of purity as, or complying with the standard of, Water for Injection (WFI), as defined in the European Pharmacopoeia (Ph. Eur.) 11.4, monograph no. 0169 and / or in US Pharmacopoeia (USP) monograph no. 1231. In one embodiment, the water consists essentially of water having an equivalent or higher level of purity as, or complying with the standard of, Water for Injection (WFI), as defined in the European Pharmacopoeia (Ph. Eur.) 11.4, monograph no. 0169, and / or in US Pharmacopoeia (USP) monograph no. 1231. In one embodiment, the water consists of water having an equivalent or higher level of purity as, or complying with the standard of, Water for Injection (WFI), as defined in the European Pharmacopoeia (Ph. Eur.)

[0436] 11.4, monograph no. 0169, and / or in US Pharmacopoeia (USP) monograph no. 1231.

[0437] In these embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is preferably Compound 1 or a pharmaceutically acceptable salt thereof. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.5 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.6 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be selected from the group of integers or decimals of about: 7.0, 7.1 , 7.2, 7.3,

[0438] 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0.

[0439] MEDICAL USE

[0440] In the first aspect of the present invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is for use as a medicament in the treatment of endometrial cancer. In other words, in the first aspect of the present invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is for use in a method of treating endometrial cancer.

[0441] In the second aspect of the present invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is for use as a medicament in the treatment of cancer. In other words, in the second aspect of the present invention, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is for use in a method of treating cancer.

[0442] The present invention also provides a method for treating and / or preventing endometrial cancer, comprising administering an antibody-drug conjugate, or pharmaceutically acceptable salt thereof according to the first aspect of the invention to a subject in need thereof.

[0443] The present invention also provides a method for treating and / or preventing cancer, comprising administering an antibody-drug conjugate, or pharmaceutically acceptable salt thereof according to the second aspect of the invention to a subject in need thereof. The present invention also provides a use of an antibody-drug conjugate, or pharmaceutically acceptable salt thereof according to the first aspect of the invention in the manufacture of a medicament for the treatment and / or prevention of endometrial cancer, in a subject.

[0444] The present invention also provides a use of an antibody-drug conjugate, or pharmaceutically acceptable salt thereof according to the second aspect of the invention in the manufacture of a medicament for the treatment and / or prevention of a cancer in a subject.

[0445] In some embodiments of the second aspect of the present invention, the patient may have been determined to have a cancer which is a HER2 positive cancer. In some embodiments of the second aspect of the present invention, the patient may have been determined to have a cancer which is a HER2 overexpressive cancer. It will be understood that a “HER2 positive cancer” or “HER2 overexpressive cancer” is a cancer that is associated with increased expression of HER2, wherein the levels of expression of HER2 are considered to be increased compared to the expression of HER2 in, for example, a non-cancerous cell or tissue, which may not express HER2, or may express HER2 at baseline levels.

[0446] In some embodiments of the second aspect of the present invention, the patient may have been determined to have a cancer which is a HER2 low cancer. In some embodiments of the second aspect of the present invention, the patient may have been determined to have a cancer which is a HER2 negative cancer. It will be understood that a “HER2 low cancer” or “HER2 negative cancer” is a cancer that is not associated with expression of HER2 or is associated with low levels of expression of HER2, wherein the low levels of expression of HER2 are considered to be reduced compared to the expression of HER2 in, for example, a non-cancerous cell or tissue.

[0447] In some embodiments of the second aspect of the present invention, the cancer is HER2- overexpressing cancer (also described herein as HER2 positive cancer).

[0448] In some embodiments, the HER2-overexpressing cancer is cancer given a score of 3+ for the expression of HER2 in an immunohistochemical method.

[0449] In some embodiments, the HER2-overexpressing cancer is cancer given a score of 2+ for the expression of HER2 in an immunohistochemical method and determined as positive for the expression of HER2 in an in situ hybridization method. The in situ hybridization method of the present invention includes a fluorescence in situ hybridization method (FISH) and a dual color in situ hybridization method (DISH). In some embodiments, the cancer is HER2 low-expressing cancer (also described herein as HER2 low cancer).

[0450] In some embodiments, the HER2 low-expressing cancer is cancer given a score of 2+ for the expression of HER2 in an immunohistochemical method and determined as negative for the expression of HER2 in an in situ hybridization method.

[0451] In some embodiments, the HER2 low-expressing cancer is cancer given a score of 1+ for the expression of HER2 in an immunohistochemical method.

[0452] In some embodiments, the HER2 low-expressing cancer is cancer given a score of >0 and <1+ for the expression of HER2 in an immunohistochemical method.

[0453] The method for scoring the degree of HER2 expression by the immunohistochemical method, or the method for determining positivity or negativity to HER2 expression by the in situ hybridization method is not particularly limited as long as it is recognized by those skilled in the art. Examples of the method can include a method described in ASCO 2018 for Breast and Endometrial Cancer. In particular, algorithms for evaluation of HER2 protein expression by immunohistochemistry (I HC) assay of the invasive component of a breast cancer specimen, by in situ hybridization (ISH) assay of the invasive component of a breast cancer specimen using a single-signal (HER2 gene) assay (single-probe ISH), and by in situ hybridization (ISH) assay of the invasive component of a breast cancer specimen using a dual-signal (HER2 gene) assay (dual-probe ISH), were published by ASCO in 2018. These algorithms were derived from recommendations in Human Epidermal Growth Factor Receptor 2 Testing in Breast Cancer: American Society of Clinical Oncology / College of American Pathologists Clinical Practice Guideline Focused Update.

[0454] In some embodiments of the second aspect of the present invention, the cancer may be selected from the group consisting of lung cancer, kidney cancer, urinary tract carcinoma, colorectal cancer, prostatic cancer, glioblastoma multiforme, ovarian cancer, pancreatic cancer, breast cancer, melanoma, liver cancer, bladder cancer, stomach cancer, esophageal cancer, uterine cancer, and endometrial cancer.

[0455] In some embodiments, the cancer may be a carcinoma. In some embodiments, the cancer may be an adenocarcinoma. In some embodiments, the endometrial and / or uterine cancer may be uterine serous endometrial carcinoma.

[0456] In some embodiments of the second aspect of the present invention, the cancer may be breast cancer.

[0457] In some embodiments of the second aspect of the present invention, the cancer may be a HER2 positive breast cancer.

[0458] In some embodiments of the second aspect of the present invention, the cancer may be a HER2-overexpressing breast cancer.

[0459] In some embodiments of the second aspect of the present invention, the cancer may be a HER2 low or HER2 negative breast cancer. In some embodiments of the second aspect of the present invention, the cancer may be a HER2 low breast cancer. In some embodiments of the second aspect of the present invention, the cancer may be a HER2 negative breast cancer.

[0460] In some embodiments of the second aspect of the present invention, the cancer may be endometrial cancer.

[0461] In some embodiments of the second aspect of the present invention, the cancer may be a HER2 positive endometrial cancer.

[0462] In some embodiments of the second aspect of the present invention, the cancer may be a HER2-overexpressing endometrial cancer.

[0463] In some embodiments of the second aspect of the present invention, the cancer may be a HER2 low or HER2 negative endometrial cancer. In some embodiments of the second aspect of the present invention, the cancer may be a HER2 low endometrial cancer. In some embodiments of the second aspect of the present invention, the cancer may be a HER2 negative endometrial cancer.

[0464] In some embodiments, the cancer may be advanced endometrial cancer. In some embodiments, the cancer may be metastatic endometrial cancer.

[0465] In some embodiments, the cancer may be a solid tumour. In some embodiments, the cancer may be HER2-expressing recurrent or metastatic endometrial cancer.

[0466] In some embodiments, the cancer may be HER2-low, hormone receptor positive (HR+) metastatic breast cancer.

[0467] In some embodiments, the cancer may be metastatic breast cancer in HER2-low, hormone receptor positive (HR+) patients. In some embodiments, the patients may be patients whose disease has progressed on endocrine therapy (ET).

[0468] In some embodiments, the cancer may be breast cancer in HER2-low (IHC 2+ / ISH- and IHC 1+), HR+ patients. In some embodiments, the patients may be patients whose disease has progressed on at least 2 lines of prior ET. In some embodiments, the patients may be patients whose disease has progressed within 6 months of first line ET + CDK4 / 6i in the metastatic setting.

[0469] In some embodiments of the third aspect of the present invention, the cancer is a HER2 positive breast cancer.

[0470] In some embodiments of the third aspect of the present invention, the cancer is a HER2- overexpressing breast cancer.

[0471] Preferred examples of the HER2-overexpressing breast cancer or HER2 positive breast cancer include breast cancer given a score of 3+ for the expression of HER2 in an immunohistochemical method, and a score of 2+ for the expression of HER2 in an immunohistochemical method and determined as positive for the expression of HER2 in an in situ hybridization method.

[0472] In some embodiments of the third aspect of the present invention, the cancer is unresectable breast cancer.

[0473] In some embodiments of the third aspect of the present invention, the cancer is metastatic breast cancer.

[0474] In some embodiments of the third aspect of the present invention, the cancer is a HER2 positive unresectable or metastatic breast cancer. In each of these embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is preferably Compound 1 or a pharmaceutically acceptable salt thereof. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.5 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be an integer or a decimal selected from the range of about 7.6 to about 8. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof is Compound 1 or a pharmaceutically acceptable salt thereof, and the average connection number Namay be selected from the group of integers or decimals of about: 7.0, 7.1 , 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0.

[0475] Cancer is a well known term that refer to a disease or group of diseases involving abnormal cell growth. The term “cancer” may be used interchangeably with “tumour” or “cancerous disease”.

[0476] The term "disease" and "disorder" may be used interchangeably herein, referring to an abnormal condition especially an abnormal medical condition such as an illness or injury, wherein a cell, a tissue, an organ, or an individual is not able to efficiently fulfil its function anymore. Typically, but not necessarily, a disease is associated with specific symptoms or signs indicating the presence of such disease. The presence of such symptoms or signs may thus, be indicative for a cell, a tissue, an organ, or an individual suffering from a disease. An alteration of these symptoms or signs may be indicative for the progression of such a disease. A progression of a disease is typically characterised by an increase or decrease of such symptoms or signs which may indicate a "worsening" or "bettering" of the disease. The "worsening" of a disease is characterised by a decreasing ability of a cell, tissue, organ or individual / patient to fulfil its function efficiently, whereas the "bettering" of a disease is typically characterised by an increase in the ability of a cell, tissue, an organ or an individual / patient to fulfil its function efficiently.

[0477] The terms “treat”, “treatment” and “treating” refers to lessening, reducing or improving at least one symptom associated with an existing disease or condition and / or to slow down, reduce or block the progression of the disease or condition and / or to delay or prevent the onset of symptoms (such as further symptoms) of the disease or condition. The terms “prevent”, “prevention” and “preventing” refers to preventing the onset of symptoms of a disease or condition, and as such encompasses prophylactic treatment.

[0478] In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof according to the invention may result in a lowered incidence of disease or symptoms, delayed onset of disease or symptoms, and / or reduced severity of disease or symptoms, compared to other therapies that are known in the art.

[0479] The medical uses and methods of treatment described herein may be used in combination with additional treatments and / or medicaments. For example, the medical uses and methods of treatment described herein may be combined with known chemotherapeutic, immunomodulatory and / or radiotherapy treatments in the form of a combination therapy or treatment.

[0480] In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof according to the invention may be used for the purpose of diagnostics, i.e. to diagnose HER2 cancers and / or test for HER2 expression in tissue samples such as a tissue biopsy. The antibody-drug conjugate or pharmaceutically acceptable salt thereof according to the invention may be used in any diagnostic assay, including (but not limited to) diagnostic assays involving ELISA, flow cytometry, immunohistochemistry and histology.

[0481] In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be used to provide a prognosis on disease progression. In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be used to determine suitability for further anti-cancer therapy.

[0482] In some embodiments, the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be used in a method of diagnosis on a biopsy. In some embodiments, the biopsy may be a breast biopsy. In some embodiments, the biopsy may be a uterine and / or an endometrial biopsy.

[0483] The antibody-drug conjugate or pharmaceutically acceptable salt thereof according to the invention may have inhibitory activity against in vitro proliferation of tumour cells. The inhibitory activity may be that: compared with in a culture medium of tumour cells to which a negative control or a control drug is added, the proliferation capacity of the tumour cells is reduced by no less than 1%, no less than 2%, no less than 4%, no less than 5%, no less than 8%, no less than 10%, no less than 15%, no less than 18%, no less than 20%, no less than 25%, no less than 40%, no less than 50%, no less than 60%, no less than 70%, no less than 80%, no less than 90% or no less than 95% in a culture medium to which the antibody-drug conjugate or pharmaceutically acceptable salt thereof is added. For example, the inhibitory activity may be an IC50 value (nM) for tumour cells of no more than 10000, no more than 5000, no more than 4000, no more than 3000, no more than 2000, no more than 1000, no more than 500, no more than 400, no more than 300, no more than 200, no more than 150, no more than 120, no more than 110, no more than 100, no more than 99, no more than 98, no more than 97, no more than 95, no more than 90, no more than 80, no more than 75, no more than 70, no more than 65, no more than 62, no more than 60, no more than 50, no more than 40, no more than 30, no more than 25, no more than 23, no more than 22, no more than 20, no more than 19, no more than 18, no more than 18.5, no more than 17, no more than 15, no more than 12, no more than 10, no more than 9, no more than 8.5, no more than 7, no more than 6.7, no more than 6, no more than 5.9, no more than 5.5, no more than 5.0, no more than 4.8, no more than 4.5, no more than 4.4, no more than 4, no more than 3.5, no more than 3, no more than 2.5, no more than 2, no more than 1.5, no more than 1.0, no more than 0.5, no more than 0.3, no more than 0.29, no more than 0.25, no more than 0.21 , no more than 0.20, no more than 0.18, no more than 0.17, no more than 0.15, no more than 0.12, no more than 0.10, no more than 0.09, no more than 0.08, no more than 0.07, no more than 0.06, no more than 0.05, no more than 0.04, no more than 0.03, no more than 0.02 or no more than 0.01.

[0484] The antibody-drug conjugate or pharmaceutically acceptable salt thereof according to the invention may have targeting inhibition. The targeting inhibition may be that: compared with in a culture medium of tumour cells with high expression of a specific target point to which a negative control or a control drug is added, the proliferation capacity of the tumour cells with high expression of a specific target point is reduced by no less than 1%, no less than 2%, no less than 4%, no less than 5%, no less than 8%, no less than 10%, no less than 15%, no less than 18%, no less than 20%, no less than 25%, no less than 40%, no less than 50%, no less than 60%, no less than 70%, no less than 80%, no less than 90% or no less than 95% in a culture medium to which the compound disclosed herein is added. For example, the targeting inhibition may be an IC50 value (nM), for tumour cells with high expression of a specific target point, of no more than 10000, no more than 5000, no more than 4000, no more than 3000, no more than 2000, no more than 1000, no more than 500, no more than 400, no more than 300, no more than 200, no more than 185, no more than 150, no more than 120, no more than 110, no more than 100, no more than 99, no more than 98, no more than 97, no more than 95, no more than 91 , no more than 80, no more than 74, no more than 70, no more than 65, no more than 62, no more than 60, no more than 50, no more than 40, no more than 30, no more than 25, no more than 23, no more than 22, no more than 20, no more than 19, no more than 18, no more than 18.5, no more than 17, no more than 15, no more than 12, no more than 10, no more than 9, no more than 8.5, no more than 7, no more than 6.7, no more than 6, no more than 5.9, no more than 5.5, no more than 5.0, no more than 4.8, no more than 4.5, no more than 4.4, no more than 4, no more than 3.5, no more than 3, no more than 2.5, no more than 2, no more than 1.5, no more than 1.0, no more than 0.5, no more than 0.3, no more than 0.29, no more than 0.25, no more than 0.21 , no more than 0.20, no more than 0.18, no more than 0.17, no more than 0.15, no more than 0.12, no more than 0.10, no more than 0.09, no more than 0.08, no more than 0.07, no more than 0.06, no more than 0.05, no more than 0.04, no more than 0.03, no more than 0.02 or no more than 0.01.

[0485] The antibody-drug conjugate or pharmaceutically acceptable salt thereof according to the invention may have plasma stability. The plasma stability may be that: the antibody-drug conjugate or pharmaceutically acceptable salt thereof releases no more than 50%, no more than 40%, no more than 30%, no more than 20%, no more than 10%, no more than 7%, no more than 5%, no more than 4%, no more than 3%, no more than 2%, no more than 1.9%, no more than 1.8%, no more than 1.7%, no more than 1.6%, no more than 1.5%, no more than 1.4%, no more than 1.3%, no more than 1.2%, no more than 1.1 %, no more than 1.0%, no more than 0.9%, no more than 0.8%, no more than 0.7%, no more than 0.6%, no more than 0.5%, no more than 0.4%, no more than 0.3%, no more than 0.2% or no more than 0.1 % of the cytotoxic drug 1 day, 3 days, 5 days, 7 days, 14 days, 20 days or 30 days after the compound is added to plasma.

[0486] The antibody-drug conjugate or pharmaceutically acceptable salt thereof according to the invention may have in vivo tumour-inhibiting effect. The tumour-inhibiting effect may be that: compared with the case where a negative control or a control drug is administered to a subject, the tumour of the subject is reduced in volume by no less than 1 %, no less than 2%, no less than 4%, no less than 5%, no less than 8%, no less than 10%, no less than 15%, no less than 18%, no less than 20%, no less than 25%, no less than 40%, no less than 50%, no less than 55%, no less than 60%, no less than 70%, no less than 73%, no less than 75%, no less than 80%, no less than 90% or no less than 95% 1 day, 3 days, 5 days, 7 days, 14 days, 20 days, 21 days or 30 days after the antibody-drug conjugate or pharmaceutically acceptable salt thereof is administered, or the tumour of the subject is reduced in volume by no less than 1 .1 fold, no less than 1.3 fold, no less than 1.5 fold, no less than 2 fold, no less than 3 fold, no less than 5 fold, no less than 10 fold, no less than 20 fold, no less than 22 fold, no less than 30 fold, no less than 50 fold, no less than 100 fold, no less than 500 fold, no less than 1000 fold or no less than 1500 fold 1 day, 3 days, 5 days, 7 days, 14 days, 20 days, 21 days or 30 days after the antibody-drug conjugate or pharmaceutically acceptable salt thereof is administered. The antibody-drug conjugate or pharmaceutically acceptable salt thereof according to the invention may have good in vivo safety. The in vivo safety may be that: after the antibody-drug conjugate or pharmaceutically acceptable salt thereof is administered to a subject, the release rate of in vivo free toxin in the subject is no more than 50%, no more than 40%, no more than 30%, no more than 20%, no more than 10%, no more than 7%, no more than 5%, no more than 4%, no more than 3%, no more than 2%, no more than 1.9%, no more than 1.8%, no more than 1.7%, no more than 1.6%, no more than 1.5%, no more than 1.4%, no more than 1.3%, no more than 1.2%, no more than 1.1 %, no more than 1.0%, no more than 0.9%, no more than 0.8%, no more than 0.7%, no more than 0.6%, no more than 0.5%, no more than 0.4%, no more than 0.3%, no more than 0.2% or no more than 0.1%. For example, the in vivo safety may be that: the antibody-drug conjugate or pharmaceutically acceptable salt thereof may be administered at a concentration of no less than 0.5 mg / kg, no less than 1 mg / kg, no less than 2 mg / kg, no less than 3 mg / kg, no less than 4 mg / kg, no less than 5 mg / kg, no less than 10 mg / kg, no less than 20 mg / kg, no less than 30 mg / kg, no less than 50 mg / kg, no less than 70 mg / kg, no less than 100 mg / kg, no less than 200 mg / kg, no less than 500 mg / kg or no less than 1000 mg / kg without causing toxic manifestation in the subject.

[0487] SUBJECT

[0488] In some embodiments, the subject of the medical uses and methods of treatment according to the present invention may be a mammal.

[0489] In some embodiments, the subject may be a human.

[0490] In some embodiments, the subject may alternatively be a non-human mammal, including for example, a primate, a monkey, a dog, a cat, a horse, a cow, a sheep, a pig, a rabbit, a rat, or a mouse.

[0491] In some embodiments, the subject may be a patient, such as a human patient.

[0492] In some embodiments, the subject may suffer from and / or have been diagnosed with one or more cancer(s).

[0493] PREVIOUSLY TREATED SUBJECTS

[0494] In some embodiments, the compound of formula (I), especially Compound 1 , is used in a method of treating metastatic breast cancer in HER2-low, hormone receptor positive (HR+) patients whose disease has progressed on endocrine therapy (ET). In some embodiments, the compound of formula (I), especially Compound 1 , is used in a method of treating breast cancer, especially in HER2-low (IHC 2+ / ISH- and IHC 1+), HR+ patients whose disease has progressed on at least 2 lines of prior ET or within 6 months of first line ET + CDK4 / 6i in the metastatic setting.

[0495] In the third aspect of the invention, the compound of formula (I), especially Compound 1 , is used in a method of treating breast cancer in a patient previously treated with an anti-HER2 antibody and / or a taxane.

[0496] In some embodiments of the third aspect of the invention, the anti-HER2 antibody previously used to treat the patient is selected from the group consisting of trastuzumab, pertuzumab and margetuximab, or a biosimilar of any thereof.

[0497] It will be understood a biosimilar of any of the recited antibodies encompasses any version of the antibody, or a variant thereof.

[0498] In some embodiments of the third aspect of the invention, the anti-HER2 antibody is trastuzumab or a biosimilar thereof.

[0499] It will be understood that trastuzumab is sold under the brand name Herceptin®.

[0500] In the third aspect of the invention, the compound of formula (I) is used in a method of treating breast cancer in a patient previously treated with trastuzumab and a taxane.

[0501] In one aspect, the compound of formula (I) is used in the treatment of HER2-positive unresectable / metastatic breast cancer in patients who have been treated with trastuzumab and a taxane.

[0502] In some embodiments of the third aspect of the invention, the taxane is selected from the group consisting of paclitaxel, docetaxel, cabazitaxel, and nab-paclitaxel.

[0503] GENERAL TERMS AND DEFINITIONS

[0504] The term “treatment cycle” takes its normal meaning in the field of oncology to mean a period of time over which an anti-cancer drug is administered, followed by a rest period during which the drug is not administered. In the context of the present disclosure, the term "about" denotes an interval of accuracy that the person of ordinary skill will understand to still ensure the technical effect of the feature in question. The term typically indicates deviation from the indicated numerical value by ±10%, such as ±9%, ±8%, ±7%, ±6%, ±5%, ±4%, ±3%, ±2%, ±1 %, ±0.9%, ±0.8%, ±0.7%, ±0.6%, ±0.5%, ±0.4%, ±0.3%, ±0.2%, ±0.1%, ±0.05%, and for example ±0.01 %. As will be appreciated by the person of ordinary skill, the specific such deviation for a numerical value for a given technical effect will depend on the nature of the technical effect. For example, a natural or biological technical effect may generally have a larger such deviation than one for a man-made or engineering technical effect. The term “about” allows to account for technical measurement uncertainty and variations when referring for example to a particular quantity or concentration.

[0505] The term “polypeptide” is used in the conventional sense to mean a series of amino acids, typically L-amino acids, connected one to the other, typically by peptide bonds between the a- amino and carboxyl groups of adjacent amino acids. The term “polypeptide” is used interchangeably with the terms “amino acid sequence”, “peptide” and / or “protein”. The term “residues” is used to refer to amino acids in an amino acid sequence.

[0506] The term "variant" refers to a polypeptide that has an equivalent function to the amino acid sequences described herein, but which includes one or more amino acid substitutions, insertions or deletions.

[0507] The sequence may have one or more deletions, insertions or substitutions of amino acid residues which produce a silent change and result in a functionally equivalent molecule. These sequences are encompassed by the present invention. Deliberate amino acid substitutions may be made on the basis of similarity in polarity, charge, solubility, hydrophobicity, hydrophilicity, and / or the amphipathic nature of the residues as long as the activity is retained.

[0508] For example, negatively charged amino acids include aspartic acid and glutamic acid; positively charged amino acids include lysine and arginine; and amino acids with uncharged polar head groups having similar hydrophilicity values include leucine, isoleucine, valine, glycine, alanine, asparagine, glutamine, serine, threonine, phenylalanine, and tyrosine.

[0509] As used herein, “variant” is synonymous with “mutant” and refers to a polynucleotide or amino acid sequence which differs in comparison to the corresponding wild-type sequence. The term “wild-type” is used to mean a gene or protein having a polynucleotide or amino acid sequence respectively, which is identical with the native gene or protein respectively. The nucleic acid sequence may be an RNA or DNA sequence or a variant thereof. The term "polynucleotide" includes an RNA or DNA sequence. It may be single or double stranded. It may, for example, be genomic, recombinant, mRNA or cDNA.

[0510] The terms “selectively binds / selectively binding” and “specifically binds / specifically binding” may be used interchangeably herein.

[0511] This disclosure is not limited by the exemplary methods and materials disclosed herein, and any methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of this disclosure. Numeric ranges are inclusive of the numbers defining the range. Unless otherwise indicated, any nucleic acid sequences are written left to right in 5' to 3' orientation; amino acid sequences are written left to right in amino to carboxy orientation, respectively.

[0512] Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limits of that range is also specifically disclosed. Each smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in that stated range is encompassed within this disclosure. The upper and lower limits of these smaller ranges may independently be included or excluded in the range, and each range where either, neither or both limits are included in the smaller ranges is also encompassed within this disclosure, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in this disclosure.

[0513] It must be noted that as used herein and in the appended claims, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise.

[0514] The terms "comprising", "comprises" and "comprised of as used herein are synonymous with "including", "includes" or "containing", "contains", and are inclusive or open-ended and do not exclude additional, non-recited members, elements or method steps. The terms "comprising", "comprises" and "comprised of' also include the term "consisting of'.

[0515] The terms “identity” and “% sequence identity” as used herein, may refer to the proportion of nucleotides or amino acids (expressed in percent) of a contiguous nucleotide sequence or contiguous amino acid sequence respectively which across the sequence, are identical to a reference sequence. The identity is calculated by counting the number of aligned nucleobases or amino acids that are identical (a Match) between the sequence of interest and a reference sequence, and dividing that number by the total number of nucleotides amino acids respectively and multiplying by 100. Therefore, Percentage of Identity = (Matches x 100) / Length of aligned region. Insertions and deletions are not allowed in the calculation the percentage of identity. Chemical modifications of nucleotides may be disregarded provided that the functional capacity to form Watson Crick base pairing is retained.

[0516] Identity comparisons can be conducted by eye, or more usually, with the aid of readily available sequence comparison programs. These commercially available computer programs can calculate % identity between two or more sequences. A suitable computer program for carrying out such an alignment is the GCG Wisconsin Bestfit package (University of Wisconsin, U.S.A.; Devereux et al., 1984, Nucleotide sequences Research 12:387). Examples of other software than can perform sequence comparisons include, but are not limited to, the BLAST package (see Ausubel et al., 1999 ibid - Chapter 18), FASTA (Atschul et al., 1990, J. Mol. Biol., 403-410) and the GENEWORKS suite of comparison tools. Both BLAST and FASTA are available for offline and online searching. For example, the percentage identity between two polypeptide sequences may be readily determined by BLAST which is freely available at http: / / blast.ncbi.nlm.nih.gov.

[0517] Once the software has produced an optimal alignment, it is possible to calculate % identity. The software typically does this as part of the sequence comparison and generates a numerical result.

[0518] The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that such publications constitute prior art to the claims appended hereto.

[0519] This disclosure is not limited by the exemplary methods and materials disclosed herein, and any methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of this disclosure. Numeric ranges are inclusive of the numbers defining the range. Unless otherwise indicated, any nucleic acid sequences are written left to right in 5' to 3' orientation; amino acid sequences are written left to right in amino to carboxy orientation, respectively. The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that such publications constitute prior art to the claims appended hereto.

[0520] The invention will now be further described by way of Examples, which are meant to serve to assist one of ordinary skill in the art in carrying out the invention and are not intended in any way to limit the scope of the invention.

[0521] EXAMPLES

[0522] Example 1 - Synthesis of Compound 1

[0523] Synthesis of Intermediate 1 - (1 S,3R)- / V-((1 S,9S)-9-ethyl-5-fluoro-9-hydroxy-4-methyl-10,13- dioxo-2,3,9, 10, 13, 15-hexahydro-1 H, 12 / 7-benzo[de]pyrano[3',4':6,7]indolizino[1 , 2-£>]qu i nol i n- 1-yl)-3-hydroxycyclobutane-1-carboxamide

[0524] Step 1 :

[0525] DIEA (500 mg, 3.87 mmol) was added to a solution of Intermediate 1z (900 mg, 1.69 mmol), HATU (691 mg, 1.88 mmol) and Intermediate 1a (320 mg, 2.00 mmol) in DMF (18 mL) at 0 °C under nitrogen atmosphere, and the mixture was stirred at 25 °C for 3 h. After the starting material was consumed completely as detected by TLC (EA), the reaction solution was added dropwise to deionized water (320 mL) and filtered to give a grey solid (850 mg, yield: 87%).

[0526] Step 2.

[0527] NaHCOs (42 mg, 0.50 mmol) as a solid was added to a solution of Intermediate 1 b (100 mg, 0.174 mmol) in MeOH / DCM (1 / 1 , 3 mL), and the mixture was stirred at 25 °C for 3 h. After the reaction was completed as detected by TLC (EA), the reaction solution was filtered, dried by rotary evaporation at low temperature, slurried with aq. HCI (0.5 M, 10 mL), filtered and purified by prep-HPLC (0.1% TFA), and then lyophilized to give a grey solid (15 mg, yield: 16%).

[0528] MS m / z (ESI): 534 [M+1]

[0529] H-NMR (400 MHz, DMSO-D): 8.45(d, 1 H), 7.81 (d, 1 H), 7.32 (s, 1 H), 6.52 (m, 1 H), 5.58-5.56 (m, 1 H), 5.44 (s, 2H), 5.14 (dd, 2 H), 3.96 (m, 1 H), 3.48 (m, 1 H), 3.19 (m, 2H), 2.53-2.28 (m, 3H), 2.48 (s, 3H), 2.20-2.00(m, 4H), 1.95-1.80 (m, 2H), 0.89 (t, 3H)

[0530] Synthesis of Intermediate 2. (1R,3R)-4-(((S)-7-benzyl-19-(2,5-dioxo-2,5-dihydro-1 / 7-pyrrol-1- yl)-3,6,9,12,15-pentaoxo-2,5,8,11 ,14-pentaazanonadecyl)oxy)- / V-((1 S,9S)-9-ethyl-5-fluoro-9- hydroxy-4-methyl-10, 13-dioxo-2,3,9, 10, 13, 15-hexahydro-1 / 7,12 / 7-benzo[de]pyrano- [3',4':6,7]indolizino[1 ,2-b]quinolin-1-yl)cyclobutane-1-carboxamide

[0531]

[0532] Step 1.

[0533] Benzyl bromide (11.0 g, 64.6 mmol) was added dropwise to a solution of Intermediate 2a (5.00 g, 43.0 mmol) and NaHCOs (10.9 g, 129 mmol) in DMF (50 mL) under nitrogen atmosphere, and the mixture was reacted at 25 °C for 17 h. After the reaction was completed as detected by TLC (PE / EA = 2 / 1), the reaction solution was added to water (500 mL), extracted with EA (250 mL) twice, separated and washed with saturated aqueous sodium chloride solution (500 mL). The organic phase was dried over anhydrous Na2SC>4, concentrated and purified by column chromatography (PE:EA = 3:2) to give a colourless liquid (5.1 g, yield: 57.1%). Step 2.

[0534] A solution of Intermediate 2b (4.50 g, 21.8 mmol) in THF (10 mL) was added dropwise to a solution of Intermediate 2z (4.00 g, 10.9 mmol) and TsOH (800 mg, 4.65 mmol) in THF (30 mL) at 0 °C under nitrogen atmosphere, and the mixture was reacted at 25 °C for 2 h. After the reaction was completed as detected by TLC (PE / EA = 1 / 2), the reaction solution was added to water (200 mL), extracted with EA (200 mL) twice and separated. The organic phase was dried over anhydrous Na2SO4, concentrated and purified by column chromatography (PE / EA = 3 / 2) to give a white solid (1.56g, yield: 26%).

[0535] Step 3.

[0536] Pd / C (80 mg) was added to a mixed solution of Intermediate 2c (800 mg, 1.55 mmol) in EtOH (8 mL) and EA (8 mL) at 0 °C under hydrogen atmosphere, and the mixture was stirred at 0 °C for 2.5 h. After the reaction was completed as detected by LCMS, the reaction solution was filtered through Celite®, and the filter cake was washed with EA (200 mL). The filtrate was concentrated, dissolved with THF (20 mL) and dried by rotary evaporation to give a white solid (600 mg, yield: 91%).

[0537] Step 4.

[0538] DIEA (152 mg, 1.18 mmol) was added to a solution of Intermediate 2d (220 mg, 0.515 mmol), Intermediate 1z (250 mg, 0.47 mmol) and HATU (214 mg, 0.56 mmol) in DMF (6 mL) at 0 °C under nitrogen atmosphere, and the mixture was reacted at 0 °C for 2 h. After the reaction was completed as detected by LCMS, the reaction solution was added to an aqueous citric acid solution (pH = 4) (150 mL), and filtered. The filter cake was washed with water (175 mL), dried under filtration, and dried with an oil pump to give a brown solid (260 mg, yield: 66%).

[0539] Step 5.

[0540] Diethylamine (8 mL) was added dropwise to a solution of Intermediate 2e (260 mg, 0.309 mmol) in DCM (30 mL) at 0 °C under nitrogen atmosphere, and the mixture was reacted at 0 °C for 3 h. After the reaction was completed as detected by LCMS, the reaction solution was added to a petroleum ether solution (600 mL) at 0 °C, and a solid was precipitated. The resulting mixture was left to stand until the solid was adsorbed on the bottom of the flask, and the solution was poured out and dried with an oil pump to give a brown solid (90 mg, yield: 47.1%). Step 6.

[0541] HATLI (74 mg, 0.19 mmol) was added to a solution of Intermediate 2f (90 mg, 0.13 mmol), Intermediate 2y (92 mg, 0.19 mmol) and DIEA (50 mg, 0.39 mmol) in DMF (2.5 mL) at 0 °C under nitrogen atmosphere, and the mixture was reacted at 0 °C for 2 h. After the reaction was completed as detected by LCMS, the reaction mixture was added to an aqueous citric acid solution (30 mL) at pH 4 at 0 °C, and a flocculent solid was precipitated. The resulting mixture was filtered, and purified by PTLC (DCM / MeOH = 10 / 1) to give a pale yellow solid (9.2 mg, yield: 6%).

[0542] MS m / z (ESI): 1074 [M+1]

[0543] H-NMR (400 MHz, MeOD): 7.65 (d, 1 H), 7.62 (s, 1 H), 7.30-7.21 (m, 5H), 6.79 (s, 2H), 5.69- 5.65 (m, 1 H), 5.57 (d, 1 H), 5.43-5.10 (m, 3H), 4.70 (d, 2H), 4.48-4.39 (m, 2H), 4.10-4.05 (m, 1 H), 4.01-3.75 (m, 5H),3.46 (t, 2H), 3.22-3.15 (m, 2H), 3.07-3.00 (m, 1 H), 2.75 (m, 1 H), 2.62 (m, 1 H), 2.45 (s, 3H), 2.37-2.20 (m, 6H), 2.10-2.02 (m, 2H), 2.00-1.92 (m, 2H) 1.68-1.57 (m, 6H), 1.01 (t, 3H)

[0544] Synthesis of Compound 1

[0545] The antibody trastuzumab is thawed at room temperature. EDTA solution (20 mM) and a reduction buffer (20 mM PB, 150 mM NaCI, pH 6.9 ± 0.1) are added to the antibody solution. Then 0.5 M Na2HPO4 or 0.3 M Na^PCL buffer is used to adjust the pH to 7.0. Tris (2- carboxyethyl) phosphine (TECP) hydrochloride powder is weighed and dissolved in water for injection (WFI) to prepare a TCEP solution. Then the solution is added to the antibody solution (TCEP to antibody molar ratio is 8-10). The reduction reaction lasts 2.0 - 4.0 hours at room temperature. The linker-payload Intermediate 2 powder is weighed and dissolved in dimethylsulfoxide (DMSO). Then the linker-payload DMSO solution is added to the mixing bag reactor. After addition of Intermediate 2 DMSO solution, the organic phase concentration is 10% (v / v) and Intermediate 2 / mAb molar ratio is 13. The conjugation reaction is allowed to proceed for 2.0 -6.0 hours at room temperature. After conjugation, the ADC solution is purified by LIF / DF, with the dialysis buffer of 25 mM Histidine buffer, pH 5.5. The ADC concentration is 20.2 mg / mL and the drug to antibody ratio (DAR) value is determined as 7.8 by RP-HPLC method.

[0546] RP-HPLC method

[0547] The drug to antibody ratio (DAR) distribution is detected by reducing ADC molecules to separated heavy chain and light chain, then further separating and quantifying each LC and HC species of different linker payload numbers with reversed phase high performance liquid chromatography (RP-HPLC). The details of the RP-HPLC method is provided in Table 1 below.

[0548] Table 1

[0549] Example 2 - Phase 1 / 2a study of Compound 1 in endometrial cancer

[0550] Methods

[0551] The Phase 1 / 2a, multicentre, open-label, first in human study is ongoing to assess the safety, tolerability, pharmacokinetics, and preliminary anti-tumour activity of the Compound 1 in subjects with advanced / metastatic solid tumours. The study consists of two parts: Part 1 (Phase 1, dose-escalation) adopts an accelerated titration at first dose followed by classic “3+3” design to identify the maximum tolerated dose (MTD) / recom mended phase 2 dose (RP2D) with seven doses ranging from 2.2 to 12 mg / kg; Part 2 (Phase 2a, dose-expansion) is initiated to assess safety / tolerability and efficacy in subjects with selected HER2- expressing or HER2-mutant malignant solid tumours. The study includes subjects with HER2-expressing (immunohistochemistry [IHC] 1 / 2 / 3+ or in situ hybridization [ISH] +) advanced / unresectable, recurrent, or metastatic endometrial cancer who are refractory to or intolerable to standard treatment, or for which no standard treatment is available. Compound 1, formulated as Composition 1 , is administered intravenously once every 3 weeks until disease progression, withdrawal of consent, or unacceptable toxicity. Adverse events (AEs) are coded using Medical Dictionary for Regulatory Activities (MedDRA) and graded according to the National Cancer Institute’s Common Terminology Criteria for Adverse Events (NCI-CTCAE, version 5.0). Tumour responses are assessed according to the Response Evaluation Criteria in Solid Tumours (RECIST, version 1.1).

[0552] Results

[0553] As of May 8, 2023, 32 subjects with endometrial cancer had received 7 or 8 mg / kg doses of Compound 1. The most common histological sub-type was uterine serous papillary carcinoma (LISPC, 34.4%), adenocarcinoma (25.0%), and uterine carcinosarcoma (UCS, 18.8%). The median treatment duration was 2.6 (range, 0.7-10.4) months with 29 subjects (90.6%) remaining on treatment. Median number of prior regimens for metastatic disease was 2 (range, 1-10). Nineteen subjects (59.4%) had prior immunotherapy therapy. A total of 17 subjects were evaluable for response. Ten subjects (58.8%) had objective partial tumour response (4 confirmed, and 6 requiring further confirmation) per RECIST 1.1 : 7 LISPC (87.5%, 7 / 8), 1 UCS (50.0%, 1 / 2), 1 mixed adenocarcinoma (50.0%, 1 / 2), and 1 adenocarcinoma (33.3%, 1 / 3). The objective response rates (ORRs) for subjects at 7 and 8 mg / kg dose were 50.0% (2 / 4) and 61.5% (8 / 13), respectively. The overall disease control rate (DCR) was 94.1%. The best overall tumour change from baseline in efficacy-evaluable subjects is shown in Figure 1, and the depth and duration of response in efficacy-evaluable subjects is shown in Figure 2. Treatment-emergent adverse events (TEAEs) of any grade occurred in 30 subjects (93.8%), and the most common (>20%) were nausea (50.0%), fatigue (31.2%), and vomiting (28.1%); of >grade 3 occurred in 10 subjects (31.2%), and the most common (>5%) were hypokalaemia (12.5%), anaemia (6.2%), and syncope (6.2%). No TEAEs led to drug discontinuation or death. No interstitial lung disease occurred.

[0554] As of Dec 14, 2023, 118 subjects with endometrial cancer had received 7 or 8 mg / kg doses of Compound 1. The most common histological sub-types were adenocarcinoma (30.5%), uterine serous papillary carcinoma (LISPC, 25.4%), and uterine carcinosarcoma (UCS, 11.9%). The median treatment duration was 3.0 (range, 0.7-11.9) months with 71 subjects (60.2%) remaining on treatment. Median number of prior regimens for metastatic disease was 2 (range, 1-8). Eighty subjects (67.8%) had prior immunotherapy therapy. A total of 91 subjects were evaluable for response. One subject had a complete response (CR) and thirtyseven subjects had a partial response (PR). The confirmed objective response rates (ORR) was 41.8% (38 / 91). The ORRs for subjects with HER2-expressing at 7 and 8 mg / kg dose were 50.0% (2 / 4) and 42.9% (36 / 84), respectively. The overall disease control rate (DCR) was 89.0%. The best overall tumour change from baseline in efficacy-evaluable subjects is shown in Figure 4, and the depth and duration of response in efficacy-evaluable subjects is shown in Figure 5. Treatment-emergent adverse events (TEAEs) of any grade occurred in 107 subjects (90.7%), and the most common (>20%) were nausea (65.3%), anaemia (41.5%), vomiting (37.3%), fatigue (34.7%), platelet count decreased (29.7%), decreased appetite (28.8%), hypokalaemia (24.6%), and aspartate aminotransferase increased (21.2%); of >grade 3 occurred in 54 subjects (45.8%), and the most common (>5%) were anaemia (16.1%), platelet count decreased (12.7%), hypokalaemia (6.8%), and neutrophil count decreased (6.8%). TEAEs led to drug discontinuation occurred in 17 subjects (14.4%). TEAEs led to death occurred in 4 subjects (3.4%). Interstitial lung disease / pneumonitis occurred in 17 subjects (14.4%).

[0555] Conclusion

[0556] The Compound 1 demonstrated a manageable safety profile and promising anti-tumour activity, with high disease control in subjects with advanced / metastatic endometrial cancer.

[0557] Example 3 - Phase 1 / 2a study of Compound 1 in HER2-positive breast cancer

[0558] Methods

[0559] The Phase 1 / 2a, multicentre, open-label, first in human study is ongoing to assess the safety, tolerability, pharmacokinetics, and preliminary anti-tumour activity of the Compound 1 in subjects with advanced / metastatic solid tumours. The study consists of two parts: Part 1 (Phase 1, dose-escalation) adopts an accelerated titration at first dose followed by classic “3+3” design to identify the MTD / RP2D with seven doses ranging from 2.2 to 12 mg / kg; Part 2 (Phase 2a, dose-expansion) is initiated to assess safety / tolerability and efficacy in subjects with selected HER2-expressing or HER2-mutant malignant solid tumours. The study includes subjects with HER2-positive (IHC 3+, or IHC 2+ and ISH+) advanced / unresectable, recurrent, or metastatic breast cancer who are refractory to or intolerable to standard treatment, or for which no standard treatment is available. Compound 1, formulated as Composition 1 , is administered intravenously once every 3 weeks until disease progression, withdrawal of consent, or unacceptable toxicity. AEs are coded using MedDRA and graded according to the NCI-CTCAE version 5.0. Tumour responses are assessed according to the RECIST version 1.1.

[0560] Results

[0561] As of Jul 26, 2023, 93 subjects (2.2 mg / kg, n=1 ; 4.4 mg / kg, n=5; 6.0 mg / kg, n=15; 7.0 mg / kg, n=29; 8.0 mg / kg, n=31 ; and 10.0 mg / kg, n=12) with multiple tumour types in doseescalation and 40 subjects (8.0 mg / kg) with HER2-positive breast cancer in dose-expansion were enrolled and received >1 dose of Compound 1. The median follow-up was 7.8 (range, 0.7-16.2) months for subjects in dose-escalation and 4.6 (range, 0.7-6.4) months for subjects with HER2-positive breast cancer in dose-expansion, median treatment duration was 4.5 (range, 0.7-13.3) months and 4.2 (range, 0.7-5.9) months, and median number of prior regimens was 7.0 (range, 1-27) and 4.0 (range, 1-9), respectively. Of 89 efficacy-evaluable subjects in the dose-escalation, the ORR per RECIST v1.1 was 52.8% (47 / 89; 35 confirmed and 3 pending confirmation), DCR was 89.9% (80 / 89), 73 (82.0%) subjects exhibited a tumour size reduction from baseline (Figure 3A), median time to response (TTR) was 1.6 (range, 1.2-4.0) months, median duration of response (DoR) was 9.7 (95%CI, 5.6-not evaluable) months, and median progression free survival (PFS) was 8.4 (95%CI, 5.5-10.9) months. Of 39 efficacy-evaluable subjects with HER2-positive breast cancer in the doseexpansion, the ORR per RECIST v1.1 was 66.7% (26 / 39, 17 confirmed and 9 pending confirmation), DCR was 97.4% (38 / 39), 38 (97.4%) subjects exhibited a tumour size reduction from baseline (Figure 3B), median TTR was 1.4 (range, 1.1-2.7) months, and the 3-months PFS rate was 97.1% (95%CI, 81.4-99.6). Subgroup analyses of ORR in subjects with HER2-positive breast cancer in dose-expansion are shown in Table 1. All subjects (n=133) experienced TEAEs of which 39.1% were > Grade (G) 3; the 5 most common TEAEs were nausea (64.7%, 3.0% > G3), platelet count decreased (57.9%, 16.5% > G3), anaemia (53.4%, 6.0% > G3), vomiting (50.4%, 1.5% > G3), and increased aspartate aminotransferase (46.6%, 0.0% > G3). Of note, few subjects experienced > G3 decreased neutrophil count (3.8%, G3; 0.0%, G4) and alopecia (9.8%, G1 ; 0.8%, G2). TEAEs leading to drug discontinuation (2 subjects [1.5%], 1 drug-related per investigator assessment), TEAEs leading to death (1 [0.8%] , 7 mg / kg group, pneumonia, not drug-related per investigator assessment), and interstitial lung disease (ILD, 6 [4.5%], 4 G1 and 2 G2; 5 drug-related and 1 not drug-related per investigator assessment) were reported only during dose-escalation. No Ss G3 ILD was reported during the study. No dose-limiting toxicity occurred and the MTD has not yet been achieved in the study.

[0562] Table 2 Subgroup analyses of ORR in efficacy-evaluable subjects with HER2-positive breast cancer in dose-expansion aThe data of prior treatment lines was unknown in 4 patients.

[0563] As of Dec 14, 2023, 93 subjects (2.2 mg / kg, n=1; 4.4 mg / kg, n=5; 6.0 mg / kg, n=15; 7.0 mg / kg, n=29; 8.0 mg / kg, n=31 ; and 10.0 mg / kg, n=12) with multiple tumour types in doseescalation and 40 subjects (8.0 mg / kg) with HER2-positive breast cancer in dose-expansion were enrolled and received >1 dose of Compound 1. The median follow-up was 13.4 (range, 6.3-22.4) months for subjects in dose-escalation and 9.2 (range, 6.9-11.0) months for subjects with HER2-positive breast cancer in dose-expansion, median treatment duration was 5.6 (range, 0.7-17.7) months and 8.0 (range, 0.7-10.7) months, and median number of prior regimens was 5.0 (range, 1-24) and 3.0 (range, 1-8), respectively. Of 93 efficacy- evaluable subjects in the dose-escalation, the confirmed ORR per RECIST v1.1 was 40.9% (38 / 93), DCR was 87.1% (81 / 93), median time to response (TTR) was 1.5 (range, 1.2-4.0) months, median duration of response (DoR) was 8.97 (95%CI, 5.78-not evaluable) months, and median progression free survival (PFS) was 8.31 (95%CI, 5.45-8.54) months. Of 40 efficacy-evaluable subjects with HER2-positive breast cancer in the dose-expansion, the confirmed ORR per RECIST v1.1 was 67.5% (27 / 40), DCR was 95.0% (38 / 40), median TTR was 1.5 (range, 1.1-5.3) months, and the median PFS was 8.97 (95%CI, 8.18-not evaluable) months. Of 93 subjects in the dose-escalation, all subjects experienced TEAEs of which 57.0% were > Grade (G) 3; the 5 most common TEAEs were nausea (69.9%, 3.2% > G3), anaemia (57.0%, 12.9% > G3), platelet count decreased (53.8%, 15.1% > G3), vomiting (52.7%, 2.2% > G3), and increased aspartate aminotransferase (44.1%, 1.1% > G3). Of note, few subjects experienced > G3 decreased neutrophil count (11.8%, G3; 0.0%, G4) and alopecia (12.9%, G1 ; 1.1%, G2). TEAEs leading to drug discontinuation (9 subjects [9.7%], 7 drug-related per investigator assessment), TEAEs leading to death (1 [1.1 %], 7 mg / kg group, pneumonia, not drug-related per investigator assessment), and interstitial lung disease (ILD, 7 [7.5%], 4 G1 , 3 G2, and 1 G3; 6 drug-related and 1 not drug-related per investigator assessment) were reported during dose-escalation. Of 40 subjects (8.0 mg / kg) with HER2- positive breast cancer in dose-expansion, all subjects experienced TEAEs of which 55.0% were > Grade (G) 3; the 5 most common TEAEs were platelet count decreased (85.0%, 27.5% > G3), increased aspartate aminotransferase (67.5%, 0.0% > G3), nausea (62.5%, 2.5% > G3), vomiting (62.5%, 2.5% > G3), and anaemia (60.0%, 7.5% > G3). Of note, few subjects experienced > G3 decreased neutrophil count (12.5%, G3; 0.0%, G4) and alopecia (5.0%, G1). No TEAEs leading to death occurred. TEAEs leading to drug discontinuation (5 subjects [12.5%], all were drug-related per investigator assessment) and ILD (6 [15.0%], 3 G1 and 3 G2; 4 drug-related and 2 not drug-related per investigator assessment) were reported in subjects (8.0 mg / kg) with HER2-positive breast cancer in dose-expansion. No dose-limiting toxicity occurred and the MTD has not yet been achieved in the study.

[0564] Conclusion

[0565] The Compound 1 demonstrated a manageable safety profile and promising antitumour activity in subjects with advanced / metastatic solid tumours, especially in HER2-positive breast cancer.

[0566] Example 4 - Dose-range finding studies

[0567] Rationale

[0568] The 6 to 8 mg / kg once every 3 weeks (Q3W) doses, especially 8 mg / kg for the Compound 1 were determined based on the totality of evidence generated from efficacy and safety summary. It is supported by clinical data (data cutoff on May 29, 2023) collected from 217 subjects in the ongoing Compound 1 clinical study which comprised data from the Phase 1 (dose-escalation, 2.2 to 10 mg / kg Q3W in solid tumour), as well as data from Phase 2a (dose-expansion, 8 mg / kg Q3W in subjects with endometrial cancer, H ER-low breast cancer, and HER2-positive breast cancer. A summary of the dose justification based on the clinical efficacy and safety data are provided below.

[0569] Methods

[0570] The Phase 1 / 2a, multicentre, open-label, first in human study is ongoing to assess the safety, tolerability, pharmacokinetics, and preliminary anti-tumour activity of the Compound 1 in subjects with advanced / metastatic solid tumours. The study consists of two parts: Part 1 (Phase 1, dose-escalation) adopts an accelerated titration at first dose followed by classic “3+3” design to identify the MTD / RP2D with seven doses ranging from 2.2 to 12 mg / kg; Part 2 (Phase 2a, dose-expansion) is initiated to assess safety / tolerability and efficacy in subjects with selected HER2-expressing or HER2-mutant malignant solid tumours. The study includes subjects with HER2-expressing (IHC 1 / 2 / 3+ or ISH+) or -mutant advanced / unresectable, recurrent, or metastatic solid tumours (including endometrial cancer, HER2- low [IHC2+ and ISH-negative, or IHC1+] breast cancer, HER2-positive [IHC 3+, or IHC 2+ and ISH+] breast cancer, etc.) who are refractory to or intolerable to standard treatment, or for which no standard treatment is available. Compound 1 , formulated as Composition 1, is administered intravenously once every 3 weeks until disease progression, withdrawal of consent, or unacceptable toxicity. AEs are coded using MedDRA and graded according to the NCI-CTCAE version 5.0. Tumour responses are assessed according to the RECIST version 1.1.

[0571] Results

[0572] Overall clinical efficacy of solid tumours (As of May 29, 2023)

[0573] • As of May 29, 2023, a total of 217 subjects received at least one dose of the Compound 1 across all tumour types and doses, and 186 subjects were included in the efficacy analysis set. among these 186 subjects, 1 subject (0.5%) had a complete response (CR), 88 subjects (47.3%) achieved a partial response (PR), the unconfirmed ORR was 47.8% (95% Cl: 40.49, 55.28); of these, 31 subjects had a PR too early to be confirmed, the confirmed ORR was 28.0% (95% Cl: 21.64, 34.99), with a median DoR of 5.78 months (95% Cl: 4.27, NE). Eighty-one (81) subjects have stable disease, giving a total DCR of 91.4% (95% Cl: 86.41, 95.00). The median TTR was 1.38 months (95% Cl: 1.12, 4.04), corresponding to the first scheduled tumour assessment. The median PFS was 8.11 months (95% Cl: 5.42, NE), and the OS was limited by the immature duration of follow-up of 3.81 months (see Table 3).

[0574] • A total of 14 subjects were treated with the Compound 1 at 6 mg / kg. Of these, 9 subjects had a PR, with an unconfirmed ORR of 64.3% (95% Cl: 35.14, 87.24) and a confirmed ORR of 50.0% (95% Cl: 23.04, 76.96). Four subjects had stable disease, giving a total DCR of 92.9% (95% Cl: 66.13, 99.82). The median DoR was 5.78 (95% Cl: 5.55, NE) months, median TTR was 2.60 (95% Cl: 1.22, 2.83) months, and median PFS was 5.45 (95% Cl: 3.94, NE) months (see Table 3).

[0575] • A total of 28 subjects were treated with the Compound 1 at 7 mg / kg. Of these, 17 subjects had a PR, with an unconfirmed ORR of 60.7% (95% Cl: 40.58, 78.50), two subjects had a PR too early to be confirmed, resulting in a confirmed ORR of 46.4% (95% Cl: 27.51 , 66.13). Ten subjects had stable disease, giving a total DCR of 96.4% (95% Cl: 81.65, 99.91). The median DoR was not reached. The median TTR was 1.38 (95% Cl: 1.18, 2.69) months and median PFS was 8.38 (95% Cl: 4.27, NE) months (see Table 3).

[0576] • A total of 136 subjects were treated with the Compound 1 at 8 mg / kg. Of these, 59 subjects had a PR, with an unconfirmed ORR of 44.1% (95% Cl: 35.62, 52.88), twentyeight subjects had a PR too early to be confirmed, resulting in a confirmed ORR of 22.1% (95% Cl: 15.41, 29.97). Sixty-six subjects had stable disease, giving a total DCR of 92.6% (95% Cl: 86.89, 96.42). The median TTR was 1.35 (95% Cl: 1.12, 4.04) months. The median DoR and median PFS were not reached (see Table 3).

[0577] Overall clinical efficacy of solid tumours (As of Dec 14, 2023)

[0578] • As of Dec 14, 2023, a total of 310 subjects received at least one dose of the Compound 1 across all tumour types and doses, and 270 subjects were included in the efficacy analysis set. among these 270 subjects, 3 subject (1.1%) had a complete response (CR), 138 subjects (51.1%) achieved a partial response (PR), the unconfirmed ORR was 52.2% (95% Cl: 46.08, 58.31); of these, 9 subjects had a PR too early to be confirmed, the confirmed ORR was 42.6% (95% Cl: 36.62, 48.73), with a median DoR of 8.71 months (95% Cl: 6.74, NE). Ninety-seven (97) subjects have stable disease, giving a total DCR of 88.1% (95% Cl: 83.68, 91.75). The median TTR was 1.45 months (95% Cl: 1.12, 5.42), corresponding to the first scheduled tumour assessment. The median PFS was 8.18 months (95% Cl: 6.77, 8.41), and the OS was limited by the immature duration of follow-up of 9.49 months.

[0579] • A total of 15 subjects were treated with the Compound 1 at 6 mg / kg. Of these, 9 subjects had a PR, with an unconfirmed ORR of 60.0% (95% Cl: 32.29, 83.66) and a confirmed ORR of 46.7% (95% Cl: 21.27, 73.41). Four subjects had stable disease, giving a total DCR of 86.7% (95% Cl: 59.54, 98.34). The median DoR was 9.72 (95% Cl: 5.55, NE) months, median TTR was 2.60 (95% Cl: 1.22, 2.83) months, and median PFS was 5.45 (95% Cl: 2.43, 10.91) months.

[0580] • A total of 29 subjects were treated with the Compound 1 at 7 mg / kg. Of these, 1 subject had a CR and 16 subjects had a PR, with an unconfirmed ORR of 58.6% (95% Cl: 38.94, 76.48) and a confirmed ORR of 48.3% (95% Cl: 29.45, 67.47). Ten subjects had stable disease, giving a total DCR of 93.1% (95% Cl: 77.23, 99.15). The median DoR was 6.90 (95% Cl: 3.19, NE) months. The median TTR was 1.41 (95% Cl: 1.18, 2.99) months and median PFS was 5.59 (95% Cl: 3.02, 8.41) months.

[0581] • A total of 202 subjects were treated with the Compound 1 at 8 mg / kg. Of these, 103 subjects had a PR, with an unconfirmed ORR of 52.0% (95% Cl: 44.86, 59.04), six subjects had a PR too early to be confirmed, resulting in a confirmed ORR of 44.1% (95% Cl: 37.10, 51.20). Seventy-six subjects had stable disease, giving a total DCR of 89.6% (95% Cl: 84.55, 93.45). The median DoR was 8.71 (95% Cl: 6.74, NE) months. The median TTR was 1.48 (95% Cl: 1.12, 5.42) months and median PFS was 8.18 (95% Cl: 7.06, 8.64) months.

[0582] The above evidence suggests that Compound 1 when administered at a dose range of 6 to 8 mg / kg conferred clinical benefits in subjects with solid tumours.

[0583] Clinical efficacy of endometrial cancer (As of May 29, 2023)

[0584] • As of May 29, 2023, eight subjects were included in the efficacy evaluation in the doseescalation. Four received the Compound 1 at 7 mg / kg, while the others received 8 mg / kg. The median follow-up time was 6.92 months and 5.29 months, respectively. At the time of the DCO, two subjects in the 7 mg / kg group had achieved PR with an unconfirmed ORR of 50.0% (confirmed ORR: 50%, 2 / 4). All 8 mg / kg group subjects achieved objective responses with an unconfirmed ORR of 100.0% (confirmed ORR: 100.0%, 4 / 4), including one CR and three PRs. Median DoR and PFS were not reached (see Table 4).

[0585] • A total of 28 subjects with endometrial cancer were treated with the Compound 1 at 8 mg / kg. Of these, one subject had a CR, while 16 had a PR, with an unconfirmed ORR of 60.7% (95% Cl: 40.58, 78.50), eight subjects had a PR too early to be confirmed, resulting in a confirmed ORR of 28.6% (95% Cl: 13.22, 48.67). Nine subjects had stable disease, giving a total DCR of 92.9% (95% Cl: 76.50, 99.12). Median DoR, PFS and OS have not been reached yet (see Table 4).

[0586] • A total of 10 HER2-expressing endometrial cancer subjects who received the Compound 1 at 8 mg / kg have been followed up for >13 weeks from the first dosing, with a confirmed ORR of 70.0% (1 CR, 6 PRs) and DCR of 100.0%, median DoR was not reached; 4 subjects have been followed up for >19 weeks from the first dosing, with a confirmed ORR of 100.0% (1 CR, 3 PRs) and DCR of 100.0%, median DoR was not reached.

[0587] • In the dose-escalation, 2 (50.0%, 2 / 4) subjects in the 7 mg / kg group had discontinued study drug, and all (100.0%, 4 / 4) subjects in the 8 mg / kg group were still on study treatment, the median follow-up time of the 7 mg / kg group was slightly longer than that of the 8 mg / kg group (6.92 months vs. 5.29 months). Clinical efficacy of endometrial cancer (As of Dec 14, 2023)

[0588] • As of Dec 14, 2023, eight subjects were included in the efficacy evaluation in the doseescalation. Four received the Compound 1 at 7 mg / kg, while the others received 8 mg / kg. The median follow-up time was 13.45 months and 11.83 months, respectively. At the time of the DCO, two subjects in the 7 mg / kg group had achieved PR with an unconfirmed ORR of 50.0% (confirmed ORR: 50%, 2 / 4). All 8 mg / kg group subjects achieved objective responses with an unconfirmed ORR of 100.0% (confirmed ORR: 100.0%, 4 / 4), including four PRs. Median DoR and PFS were not reached.

[0589] • A total of 84 subjects with endometrial cancer were treated with the Compound 1 at 8 mg / kg. Of these, two subjects had a CR, while 41 had a PR, with an unconfirmed ORR of 51.2% (95% Cl: 40.04, 62.26), five subjects had a PR too early to be confirmed, resulting in a confirmed ORR of 42.9% (95% Cl: 32.11, 54.12). Thirty-one subjects had stable disease, giving a total DCR of 88.1% (95% Cl: 79.19, 94.14). The median PFS was 6.70 (95% Cl: 5.45, 8.31) months. Median DoR and OS have not been reached yet.

[0590] • A total of 76 HER2-expressing endometrial cancer subjects who received the Compound 1 at 8 mg / kg have been followed up for >13 weeks from the first dosing, with a confirmed ORR of 47.4% (1 CR, 35 PRs) and DCR of 89.5%, median DoR was not reached; 66 subjects have been followed up for >19 weeks from the first dosing, with a confirmed ORR of 53.0% (1 CR, 34 PRs) and DCR of 89.4%, median DoR was not reached.

[0591] The above evidence suggests that Compound 1 when administered at a dose of 8 mg / kg conferred clinical benefits in subjects with endometrial cancer.

[0592] Clinical efficacy of HER2-low breast cancer (As of May 29, 2023)

[0593] • As of May 29, 2023, in the dose-escalation of Compound 1 clinical study, the majority of subjects with HER2-low breast cancer were dosed with the Compound 1 at 7 mg / kg (7 subjects) and 8 mg / kg (10 subjects), with a median follow-up time of 6.90 months and 5.65 months. At the time of the DCO, one subject in the 7 mg / kg group and four in the 8 mg / kg group had achieved confirmed PR with respective confirmed ORRs of 14.3% and 40.0% (Table 5). Median DoR was not reached. The median PFS for subjects in the 7 mg / kg group was 4.27 months, while it was not reached for 8 mg / kg group (Table 5).

[0594] • To further confirm the benefit of 8 mg / kg Q3W, the ORR data for all subjects with HER2- low breast cancer during dose-escalation and dose-expansion of Compound 1 clinical study with two different follow-up durations are summarized: 33 HER2-low breast cancer subjects who have been followed up for >13 weeks from the first dosing, had an unconfirmed ORR of 45.5% (30.3% confirmed response, and 9.1% pending confirmation of response). At the same time, 10 subjects that have been followed up for >19 weeks from the first dosing, had an unconfirmed ORR of 50.0% (40.0% confirmed response).

[0595] • Additionally, among subjects with HER2-low breast cancer in the dose-escalation, those receiving 8 mg / kg Q3W remained on treatment longer than those receiving 7 mg / kg Q3W, with 40.0% (8 mg / kg Q3W) and 0% (7 mg / kg Q3W) still receiving treatment beyond 8 cycles, respectively.

[0596] Clinical efficacy of HER2-low breast cancer (As of Dec 14, 2023)

[0597] • As of Dec 14, 2023, in the dose-escalation of Compound 1 clinical study, the majority of subjects with HER2-low breast cancer were dosed with the Compound 1 at 7 mg / kg (7 subjects), 8 mg / kg (10 subjects), and 10 mg / kg (9 subjects), with a median follow-up time of 13.44 months, 12.19 months, and 6.74 months. At the time of the DCO, two subjects in the 7 mg / kg group, four in the 8 mg / kg group, and 3 subjects in the 10 mg / kg group had achieved confirmed PR with respective confirmed ORRs of 28.6%, 40.0%, and 33.3%. Median DoR was not reached. The median PFS for subjects in the 7 mg / kg group was 4.24 months and in the 8 mg / kg group was 11.14 months, while it was not reached for 10 mg / kg group.

[0598] The above evidence suggests that Compound 1 when administered at a dose of 8 mg / kg conferred clinical benefits in subjects with HER2-low breast cancer.

[0599] Clinical safety

[0600] • During the dose-escalation of Compound 1 clinical study, the Compound 1 was well tolerated at all doses ranging from 2.2 mg / kg to 10 mg / kg, the MTD of the Compound 1 was not reached at doses up to 10 mg / kg and no DLT was observed during the DLT evaluation period (Cycle 1 Days 1 to 21).

[0601] The incidence of TEAEs, TEAEs > Grade 3, SAEs, TEAEs leading to dose reduction, TEAEs leading to dose interruption, TEAEs leading to permanent drug discontinuation, and adverse events of special interest (AESIs) was similar between the subjects who received the Compound 1 at 8 mg / kg (N=159) during dose-escalation and dose-expansion, 7 mg / kg (N=29) and 6 mg / kg (N=15) during dose-escalation (Table 6). Among subjects treated with 6 to 8 mg / kg Q3W to date, the safety profile of the Compound 1 is acceptable. Table 3 Overall clinical efficacy in Compound 1 clinical study (Efficacy Analysis Set)

[0602]

[0603] ORR was calculated based on the Clopper-Pearson method. DoR, PFS and OS were calculated based on the Kaplan-Meier method. TTR was calculated using subjects with confirmed response.

[0604] Cl = confidence interval, DCR = disease control rate, DoR = duration of response, NE = not evaluable, NR = not reached, OS = overall survival, PFS =progression of disease.

[0605] Table 4 Overall clinical efficacy in subjects with endometrial cancer in Compound 1 clinical study (Efficacy Analysis Set)

[0606]

[0607] ORR was calculated based on the Clopper-Pearson method. DoR, PFS and OS were calculated based on the Kaplan-Meier method. TTR was calculated using subjects with confirmed response.

[0608] Cl = confidence interval, DCR = disease control rate, DoR = duration of response, NE = not evaluable, NR = not reached, OS = overall survival, PFS =progression of disease.

[0609] Table 5 Overall clinical efficacy in subjects with HER2-low breast cancer in Compound 1 clinical study (Efficacy Analysis Set)

[0610]

[0611] ORR was calculated based on the Clopper-Pearson method. DoR, PFS and OS were calculated based on the Kaplan-Meier method. TTR was calculated using subjects with confirmed response.

[0612] Cl = confidence interval, DCR = disease control rate, DoR = duration of response, NE = not evaluable, NR = not reached, OS = overall survival, PFS =progression of disease.

[0613] Table 6 Overview of treatment-emergent adverse events in Compound 1 clinical study (Safety Analysis Set)

[0614]

[0615]

[0616] DLT= dose-limiting toxicity, TEAE = treatment-emergent adverse event, TRAE = treatment-related adverse event.

[0617] Additional considerations

[0618] Exposure-response (E-R) analysis indicated a positive relationship between best overall response (BOR) and Cycle 1 Compound 1 exposure levels in HER2-low breast cancer patients (not shown). Therefore, doses > 7 mg / kg were considered to maximize efficacy of Compound 1 treatment based on increased exposure levels. Furthermore, the clinically observed DoR was longer in patients who received 8 mg / kg Q3W Compound 1 compared to those who received 7 mg / kg Q3W Compound 1 ; suggesting that > 8 mg / kg Q3W is the more favourable dosing regimen.

[0619] While dose-dependent increases in Compound 1 peak observed concentration (Cmax) and area under the concentration-time curve were observed, increased clearance (i.e., shorter half-life) was observed in a subset of patients in the 6 mg / kg cohort, likely due to target- mediated drug disposition, which was not seen in dose levels > 7 mg / kg. Thus, at lower dose levels < 7 mg / kg, there may be patients with suboptimal PK due to increased clearance.

[0620] Conclusions

[0621] The totality of evidence generated based on efficacy and safety data supports 6 to 8 mg / kg Q3W being optimal dose regimens for Compound 1. The doses of 6 to 8 mg / kg Q3W were well tolerated. Of note, the dose of 8 mg / kg Q3W has demonstrated a more favourable efficacy profiles in subjects with endometrial cancer and HER2-low breast cancer over lower dose levels tested in the Compound 1 clinical study and thus, provides the optimal treatment outcome in these populations.

[0622] Example 5 - Safety profile from phase 1 / 2a study of Compound 1, and comparisons with trastuzumab deruxtecan (Enhertu®)

[0623] Methods

[0624] The Phase 1 / 2a, multicentre, open-label, first in human study is ongoing to assess the safety, tolerability, pharmacokinetics, and preliminary anti-tumour activity of the Compound 1 in subjects with advanced / metastatic solid tumours. The study consists of two parts: Part 1 (Phase 1, dose-escalation) adopts an accelerated titration at first dose followed by classic “3+3” design to identify the MTD / RP2D with seven doses ranging from 2.2 to 12 mg / kg; Part 2 (Phase 2a, dose-expansion) is initiated to assess safety / tolerability and efficacy in subjects with selected HER2-expressing or HER2-mutant malignant solid tumours. The study includes subjects with HER2-positive (IHC 3+, or IHC 2+ and ISH+) advanced / unresectable, recurrent, or metastatic breast cancer who are refractory to or intolerable to standard treatment, or for which no standard treatment is available. Compound 1, formulated as Composition 1 , is administered intravenously once every 3 weeks until disease progression, withdrawal of consent, or unacceptable toxicity. AEs are coded using MedDRA and graded according to the NCI-CTCAE version 5.0. Tumour responses are assessed according to the RECIST version 1.1.

[0625] Safety Findings

[0626] As of Dec 14, 2023, a total of 310 subjects received at least one dose of the Compound 1 across all tumour types and doses, including 93 subjects in the Dose Escalation Part and 217 subjects in the Dose Expansion Part. The median treatment duration across all doses was 4.6 months (range: 0.7 to 17.7 months). Treatment duration was >3 months in 192 subjects (62.0%); 136 subjects (43.9%) were still receiving treatment at the time of the DCO.

[0627] For an overview of TEAEs for pooled 8 mg and Total refer to Table 7. When examining safety data presented for all subjects, the Compound 1 was generally well tolerated. Overall, the majority of subjects experienced at least one TEAE (295 / 310 subjects, 95.2%). There were 81 / 310 subjects (26.1%) who experienced treatment-emergent serious AEs (TESAEs), 51 / 310 subjects (16.5%) who experienced treatment-related TESAEs, and 129 / 310 subjects (41.6%) who experienced treatment-related TEAEs of Grade >3. There were 38 / 310 subjects (12.3%) with TEAEs leading to treatment discontinuation and 73 / 310 subjects (23.5%) with TEAEs leading to dose reductions.

[0628] The Compound 1 was well tolerated at all tested doses ranging from 2.2 mg / kg to 10 mg / kg (data not shown). There were some differences observed in the overall safety profile observed in subjects treated with the Compound 1 at doses of 6 mg / kg, 8 mg / kg, and 10 mg / kg. The proportion of Grade >3 TEAEs increased with dose level with 31.3% (5 / 16 subjects), 49.4% (116 / 235 subjects), and 54.2% (13 / 24 subjects), experiencing Grade >3 TEAEs in the 6 mg / kg, 8 mg / kg, and 10 mg / kg dose groups, respectively. A similar trend was observed for related Grade >3 TEAEs and TEAEs of special interest. However, for the proportion of TESAEs there was no clear difference across the treatment groups with 25.0% (4 / 16 subjects), 26.8% (63 / 235 subjects), and 8.3% (2 / 24 subjects), experiencing TESAEs in the 6 mg / kg, 8 mg / kg, and 10 mg / kg dose groups, respectively.

[0629] The MTD of the Compound 1 was not reached at doses up to 10 mg / kg and no dose-limiting toxicities (DLT) were observed during the DLT evaluation period (Cycle 1 Days 1 to 21) in the Dose Escalation Part. A total of 295 / 310 subjects (95.2%) experienced at least one TEAE, with most of the common TEAEs being gastrointestinal or haematological in nature (i.e. , nausea, platelet count decreased, vomiting, decreased appetite).

[0630] Table 7 Overview of treatment-emergent adverse events (TEAEs) in Compound 1 clinical study (Safety Analysis Set) - Pooled 8mg / kg and Total. interrupted( )( ) ( . ) ( . ) ( . ) ( . ) discontinuationt0 d°Se9 (9.7) 29 (13.4) 1 (6.3) 33 (14.0) 2 (8.3) 38 (12.3)

[0631] Related TEAEs leading to dose7 (7 5)24 (11.1) 0 28 (11.9) 2 (8.3) 31 (10.0) discontinuationv v v v v’

[0632] TEAEs leading to death 1 (1.1) 9 (4.1) 0 9 (3.8) 0 10 (3.2)

[0633] Related TEAEs leading to0 5 (2 3) 05 (2.1)05 (1.6) deathv v v'

[0634] TEAEs of special interest 15 (16.1) 34 (15.7) 1 (6.3) 39 (16.6) 4 (16.7) 49 (15.8) interestTEAES of special13 (14.0) 32 (14.7) 1 (6.3) 38 (16.2) 3 (12.5) 45 (14.5)

[0635] N = total number; n = subset of the total number; TEAE = treatment-emergent adverse effect; TESAE = treatment-emergent serious adverse event.

[0636] A comparative analysis was performed on the TEAE with data from trastuzumab deruxtecan (Enhertu®) - the results are shown in Table 8.

[0637] The TEAEs for Compound 1 for both pooled 8 mg / kg as well as Total were compared with those of a 5.4 mg / kg dose of the approved drug trastuzumab deruxtecan (Enhertu®) - the results are shown in Table 8. The data from trastuzumab deruxtecan (Enhertu®) were taken from Destiny- Breast03 study (Hurvitz SA et al., Lancet, 2023 Jan 14;401 (10371):105-117). The TEAEs for Compound 1 (any as well as JsGrade 3) were less than trastuzumab deruxtecan (Enhertu®). Table 8 Overview of treatment-emergent adverse events in Compound 1 clinical study (Safety Analysis Set) compared with trastuzumab deruxtecan (Enhertu®)

[0638] A similar trend was observed on comparison of TRAE (Treatment-emergent Related Adverse Events) as shown in Table 9 for alopecia and Gl events, wherein TRAE were reported comparatively less for Compound 1. Data for trastuzumab deruxtecan (Enhertu®), TRAE was taken from the last revised IISPI (April 2024) for trastuzumab deruxtecan (Enhertu®), specifically the table on common Adverse Reactions (>10% All Grades or >2% Grades 3-4) in Patients Treated with trastuzumab deruxtecan (Enhertu®), in the DESTINY- Breast03 trial.

[0639] Table 9 Overview of treatment-emergent related adverse events in Compound 1 clinical study (Safety Analysis Set) compared with trastuzumab deruxtecan (Enhertu®)

[0640] - includes the PTs Abdominal pain, abdominal discomfort, lower abdominal pain, and upper abdominal pain

[0641] # - includes the PTs Stomatitis, aphthous ulcer, mouth ulceration, oral mucosa erosion, and oral mucosal eruption.

[0642] Conclusion

[0643] As of Data Cut Off of 14-Dec-2013, Compound 1 demonstrated a well-tolerated and manageable safety profile in subjects with advanced / metastatic solid tumours. For certain adverse events such as gastrointestinal events and alopecia (and possibly others), Compound 1 appears to show better safety than trastuzumab deruxtecan (Enhertu®). From the latest preliminary data, a similar trend in safety for these adverse events is anticipated for specific indications such as endometrial and / or breast cancer. Example 6 - A Phase III, randomized, multi-centre, open-label trial of Compound 1 versus investigator’s choice chemotherapy in previously treated patients with HER2-expressing recurrent or metastatic endometrial cancer

[0644] HER2, which has received widespread attention in the medical field in recent years, is a member of cell-surface transmembrane receptors with tyrosine kinase activities. The HER2 gene is known to be overexpressed in more than 30% of all human cancers, including breast cancer, gastric, colon, salivary gland, bladder, and uterine serous carcinoma (Grabsch et al. 2010; Buza et al. 2013; Cocco et al. 2019), and its overexpression in tumours is associated with poor prognoses. The clinical application of HER2-targeted therapy has improved the outcome of patients with HER2 amplified / overexpressing cancers (Oh et al. 2020). However, not all patients with HER2-positive tumours respond well to current therapies. Resistance towards HER2-targeting therapies is common, occurring as either intrinsic or acquired resistance (Ogitani et al. 2016). For HER2-positive cancers beyond breast cancer and gastric cancer including heavily treated patients, there is no HER2-targeting drug approved and still lacks effective treatment.

[0645] In this Phase III trial, the safety and efficacy of Compound 1 will be compared with investigator’s choice single agent chemotherapy in patients with recurrent or metastatic endometrial cancer (including HER2 1+, 2+ or 3+ score on immunohistochemistry analysis) whose disease has progressed on at least one line of platinum-based therapy and exposure to immunotherapy.

[0646] The primary objective of this trial is to assess the efficacy of Compound 1 compared with investigator’s choice chemotherapy in terms of progression-free survival (PFS) by Blinded Independent Central Review (BICR) in the endometrial cancer population. Subsequent to the earliest priority date of the present application, the Applicants have received FDA “Breakthrough Therapy” designation for Compound 1 in endometrial cancer.

[0647] This is an open-label, randomized, multi-centre, Phase III, interventional trial designed to determine the efficacy and safety of Compound 1 compared with investigator’s choice single agent chemotherapy in previously treated patients with recurrent or metastatic endometrial cancer.

[0648] Approximately 390 patients will be randomized 2:1 to receive either Compound 1 or investigator’s choice single agent chemotherapy (doxorubicin or paclitaxel) until disease progression (PD) (per RECIST 1.1) unless there is unacceptable toxicity, withdrawal of consent, or another criterion for discontinuation is met. Randomization will be stratified by human epidermal growth factor receptor 2 (HER2) expression (IHC score 1+ vs 2+ vs 3+) and number of prior lines of therapy (1 vs 2+).

[0649] The trial consists of a screening period, a treatment period, a safety follow-up period, and a long-term survival follow-up. The screening period is up to 28 days.

[0650] Unless specific treatment discontinuation criteria are met or the patient withdraws consent, all patients will continue receiving treatment until RECIST 1.1 defined PD. After discontinuation of trial treatment, all patients will have a post-end of treatment (EOT) visit (scheduled within 7 days of end of treatment) and a safety follow-up visit (scheduled at 35 days +7 days after their last dose of trial treatment). If end of treatment occurs >35 days after the last dose of trial treatment, EOT assessments can function as safety follow-up.

[0651] Patients who have discontinued treatment for reasons other than PD will also be followed up with tumour assessments until radiological progression (or death). All patients randomized should be followed up for survival unless trial consent was withdrawn. Long-term / survival follow-up visits will be performed every 3 months (±14 days) from the date of the safety follow-up visit until death, withdrawal of consent, or trial closure, whichever occurs first.

[0652] Compound 1 will be formulated as Composition 1 and administered at a dose of 6 or 8mg / kg intravenously every 21 days (i.e. , Q3W) until PD, unacceptable adverse event, or withdrawal of patient’s consent.

[0653] Doxorubicin will be administered at a dose of 60 mg / m2as an intravenous bolus Q3W until PD, unacceptable adverse event, or withdrawal of patient’s consent.

[0654] Paclitaxel will be administered at a dose of 80 mg / m2as an intravenous infusion on Days 1 , 8, and 15 in 28-day cycles until PD, unacceptable adverse event, or withdrawal of patient’s consent.

[0655] Example 7 - A Phase III, Randomized, Multi-centre, Open-label Study of Compound 1 Versus Investigator’s Choice Chemotherapy in Human Epidermal Growth Factor Receptor 2 (HER2)- low, Hormone Receptor Positive (HR+) Metastatic Breast Cancer Patients whose Disease has progressed on Endocrine Therapy (ET)

[0656] Within breast cancers traditionally classified as HER2-negative, there exists a spectrum of HER2 expression. In addition to tumours with no detectable HER2 staining (classified by an IHC score of 0 in clinical guidelines), the category encompasses IHC 2+1 ISH negative and IHC 1+ cancers (defined in this study collectively as HER2-low).

[0657] Currently, patients with HR+, HER2-low advanced or metastatic breast cancer follow the same treatment paradigm as HR+, HER2-negative breast cancer patients. In general, ET is considered the preferred option for HR+, HER2-negative breast cancer. The optimal treatment sequence is considered to be the use of ET + CDK4 / 6 inhibitors first line, followed by subsequent ET with targeted therapies (e.g., mTOR or PI3-K inhibitors [for PI3-K mutant tumours]) (Cardoso et al 2020). In patients whose disease has progressed after multiple lines of ET with or without targeted therapies, chemotherapy may be appropriate (Cardoso et al 2018). In addition, for patients who have primary endocrine resistance (i.e. , progressive disease within the first 6 months of first-line ET for advanced breast cancer), chemotherapy may also be appropriate as continued treatment with endocrine therapies following progression on ET + CDK4 / 6 inhibitors has been shown to provide less benefit (Rossi et al 2019, Sledge et al 2020, Turner et al 2018). In the DESTI NY-BreastO4 trial, trastuzumab deruxtecan (T-DXd, Enhertu®) showed superior activity over standard chemotherapy options in patients with HER2-low advanced breast cancer, which highlights the clinical relevance of the HER2-low patient population and supports a need to redefine subgroups within HER2-negative breast cancers (Modi S et al 2022). Before this trial, few clinical trials were conducted specifically in patients with HER2-low metastatic breast cancer as defined here. Despite the approval of T-DXd for the treatment of HER2+ and HR+ / HER2-low metastatic breast cancer, disease progression occurs in most patients, compelling the use of additional therapeutic options to overcome drug resistance. The best way is to investigate much safer and more efficacious new drugs, to further optimize the treatment and outcomes of this patient population.

[0658] In the Phase 1 clinical trial described in Example 3 above, Compound 1 demonstrated promising anti-tumour activity with an unconfirmed ORR of 40.3% (95% Cl: 28.49%-53.00%) in HER2-low breast cancer as of 29 May 2023, with the majority of patients experiencing tumour shrinkage with durable responses. Data from this study suggests that the anti-tumour activity of Compound 1 has the potential to provide meaningful clinical benefit to patients with HER2-low, warranting further evaluation.

[0659] Therefore, in this Phase 3 study, Compound 1 will be compared against investigator’s choice single agent chemotherapy to determine if Compound 1 can improve outcomes in HER2-low (IHC 2+ / ISH- and IHC 1+), HR+ breast cancer patients whose disease has progressed on at least 2 lines of prior ET or within 6 months of first line ET + CDK4 / 6i in the metastatic setting (N=466).

[0660] In order to identify subjects who are likely to benefit from HER2 targeted therapies, validated companion diagnostic devices are needed in order to characterize HER2 expression I amplification in this setting. The prevalence of HER2-low in breast cancer has been characterized in the scientific literature.

[0661] Enrolling subjects for this trial of Compound 1 based on HER2-low tumour status is expected to maximize the likelihood of clinical benefit from the study treatment based on the mode of action of HER2 targeted therapies and clinical experience to date using targeted therapies in the breast oncology setting.

[0662] The study is an open-label, multi-centre, randomized study in HER2-low, HR+ breast cancer patients with disease progression on at least 2 lines of prior ET or within 6 months of first line ET + CDK4 / 6 inhibitor in the metastatic setting. The primary purpose of the study is to determine the efficacy and safety of Compound 1 compared with investigator’s choice single agent chemotherapy in the target population. Approximately 466 subjects will be randomized 1:1 across approximately 180 centres globally to receive either 6 or 8 mg / kg Compound 1 Q3W or investigator’s choice single agent chemotherapy (paclitaxel, nab-paclitaxel or capecitabine) until RECIST 1.1 defined progressive disease (PD), unless there is unacceptable toxicity, withdrawal of consent, or another criterion for discontinuation is met.

[0663] The study will compare PFS, OS and other measures of efficacy between the study treatment groups and further characterize the safety and tolerability profile of Compound 1. The randomization will be stratified as follows:

[0664] • prior CDK4 / 6 inhibitor use (Yes vs No)

[0665] • HER2 IHC expression (IHC 2+ / ISH- vs IHC 1+)

[0666] • prior taxane use in the non-metastatic setting (Yes vs No)

[0667] Stratification factor status must be known at the time of subject’s randomization to the study. CDK4 / 6 inhibitors are being increasingly utilized as part of standard of care for patients with HR+ breast cancer. To ensure that majority of subjects have received prior CDK4 / 6 inhibitor therapy in the HER2-low population, no more than 228 subjects (49% of 466 subjects) who have not received prior therapy with CDK 4 / 6 inhibitors (e.g., palbociclib, abemaciclib, or ribociclib) will be randomized. Based on all available information, a Compound 1 dose of 8 mg / kg Q3W has been chosen for this study. For each chemotherapy active, the following doses were selected:

[0668] Paclitaxel: Paclitaxel will be administered at a standard of care dose of 80 mg / m2every week.

[0669] Nab-paclitaxel: Subjects will receive 100 mg / m2nab-paclitaxel on Days 1 , 8, and 15 of each 28-day cycle.

[0670] Capecitabine: Subjects will have the option to receive either the 1250 mg / m2capecitabine dose as indicated in the label or the 1000 mg / m2capecitabine dose.

[0671] Example 8 - Composition Studies

[0672] This Example summarizes the results of a lyophilized composition confirmation study and reconstitution stability study of Compound 1. The purpose of the Compound 1 lyophilized composition confirmation study was to confirm the stability of Compound 1 in the selected composition. The purpose of Compound 1 reconstitution stability study was to investigate the stability of reconstituted Compound 1 composition in liquid state.

[0673] The composition of 20.0 mg / mL Compound 1 , 25 mM histidine, 9% (w / v) sucrose, 0.03% (w / v) polysorbate 80, pH 5.5 (Composition 1) was selected based on a preceding composition development study. The stability of the lyophilized composition was evaluated under three different temperatures, i.e. 2~8°C, 25°C and 40°C, which stand for the long-term storage condition, accelerated condition and stress condition, respectively.

[0674] Table 10. The composition of Compound 1

[0675] Example 8a - Lyophilized composition confirmation study

[0676] Sample information: Compound 1 was formulated with 20.0 mg / mL Compound 1 , 25 mM histidine, 9% (w / v) sucrose, 0.03% (w / v) polysorbate 80, pH 5.5.

[0677] Sample preparation: Drug substance solution was aseptically filtered, filled into glass vials, semi-stoppered and freeze-dried in a lyophilizer. All procedures were carried out in a biosafety hood.

[0678] Study Plan: Sampling and testing plan for the lyophilized composition confirmation study is shown in Table 8. For long-term, accelerated and stress conditions storage, samples were incubated at 2~8 °C, 25 °C and 40 °C, respectively. Samples at TO without any stress treatment were set as control. Testing items including appearance (before and after reconstitution), pH, protein concentration, SEC-HPLC, clEF, and sub-visible particles (HIAC) were performed in this study. At each sampling point, samples were retrieved and analyzed timely.

[0679] Table 11 : Sampling and testing plan of lyophilized composition confirmation study

[0680] X=Appearance (before and after reconstitution), pH, protein concentration, SEC HPLC, clEF, DAR

[0681] Y=Sub-visible particles

[0682] Z=potency, moisture content

[0683] Results and Discussion

[0684] Appearance, pH and protein concentration:

[0685] Appearance of all samples, including clarity, colour and visible particles, was observed visually against black and white background by using a YB-2 clarity detector, with the light intensity of 1000-1500 Lux.

[0686] Sample pH was measured by a pH meter with a glass electrode. The pH meter was calibrated by standard solutions of pH 4.01 , 7.00 and 9.21. Each sample was determined twice (100 pL sample each) and the average value was adopted in the report.

[0687] Protein concentration was determined by the absorbance of 280 nm and 370 nm using SoloVPE spectrophotometer. The extinction coefficient of Compound 1 mAb protein is 1.52 (mg / mL)-1crrr1.

[0688] SoloVPE system is dependent on the variable path length Spectroscopy Technology. According to Beer’s law equation: A=E*L*C, where A=Absorbance, E=Extinction Coefficient, L=Path Length, C=Concentration, Slope m= A / L can be obtained by measuring the absorbance at 10 different path lengths. Through the curve of path length and absorbance, the slope m can be calculated. As C=m / e, with E and m known, the concentration can be calculated.

[0689] The results are shown in Table 9. For the appearance of the lyophilized cake, no substantial change was observed in all the stressed samples compared to TO. After reconstitution, the appearance of the composition was colourless, slight opalescence, and free of visible particles. In addition, there was no significant variation in pH or protein concentration.

[0690] Table 12: Data summary of appearance, pH and protein concentration in lyophilized composition confirmation study

[0691] WLC=White lyophilized cake; CL=Colourless; SOSlight Opalescence; FP=Free of visible particles

[0692] SEC-HPLC: The sample was diluted to 10.0 mg / mL with mobile phase, and 100 pg of sample was then injected into a TSKgel G3000SWXL column (7.8x300 mm, 5 pm Steel / TOSOH). The analysis was performed on the Agilent 1260 HPLC system with a MWD detector (detection wavelength: 280 nm and 370 nm). The chromatographic program was a 20 min isocratic gradient with mobile phase (50 mM Phosphate Buffer, 300 mM NaCI, pH 6.8 ± 0.1) : AON = 9:1 (v / v)) at a flow rate of 1.0 mL / min.

[0693] The results are shown in Table 13. The SEC-HPLC results showed that there was no substantial change in the stability study. Table 13: Results of SEC-HPLC in lyophilized composition confirmation study

[0694] CIEF: Compound 1 samples were mixed with master mixture to generate loading mixture, which contains 2.0 pL Pharmalyte 8-10.5, 2.0 pL Pharmalyte 3-10, 35 pL 1% MC, 0.5 pL pl marker 7.05, 0.5 pL pl marker 9.46, 37.5 pL 8M Urea solution, 0.15 pL Glacial Acetic Acid, 2.35 pL ultrapure water at a final protein concentration of 0.4 mg / mL. Place loading mixture in a 2~8 °C refrigerator or a 5°C heat block for more than 48 h. The test need to be completed within 96 h after the samples being mixed with the master mix, otherwise the samples should be re-prepared. The loading mixture was loaded into a FC-Coated capillary, and analyzed with iCE3 Capillary Isoelectric Focusing Analyzer equipped with whole-column detection camera. After the analysis, the raw data were processed with Empower 3.

[0695] The CIEF results are shown in Table 14. The CIEF results indicated that no substantial change was observed in the stability study.

[0696] Table 14: Results of CIEF in lyophilized composition confirmation study visible particle size and counts under a laminar flow cabinet. To avoid introducing air bubbles and interference during examination, all samples were held in the cabinet for at least 0.5 hour before testing. Each sample was tested for four consecutive runs, 0.45 mL each. The results were presented as average number of particles of >10 pm and >25 pm per mL (method conforms to USP <788> Particulate matter in injections).

[0697] Sub-visible particles data measured by HIAC in lyophilized composition confirmation study are summarized in Table 15. Compared to TO, no substantial change of sub-visible particles was observed after storage at 2~8 °C / 25 °C / 40 °C.

[0698] Table 15: Results of sub-visible particles measured by HIAC in lyophilized composition confirmation study

[0699] The following additional studies were performed at the indicated time points:

[0700] Moisture content and reconstitution time study: no significant increase of moisture content or reconstitution times were observed after storage.

[0701] DAR and free drug stability study: no substantial changes were observed in the stability study.

[0702] Potency assay after storage and reconstitution: no substantial changes in biological activity were observed in the stability study.

[0703] Summary: In this study, Compound 1 protein was lyophilized with the final lyophilization process, and its stability was investigated after 4 weeks of storage at 40°C, or 12 weeks of storage at 25°C / 2-8°C. The above results showed that Compound 1 was stable in the selected lyophilized composition. Reconstitution stability study

[0704] Material: Compound 1 used in reconstitution stability study was prepared in lyophilized composition confirmation study, and were kept at 5°C.

[0705] Study design: The study plan is shown in Table 16.

[0706] Table 16: Reconstitution stability study plan

[0707] X= Appearance (visible particle), pH, protein concentration, SEC-HPLC, clEF, DAR, HIAC Note: The TO data of lyophilized composition confirmation study was used as TO in this study.

[0708] Sample preparation: the Drug Product from 5°C was taken out and reconstituted with ultrapure water, the reconstituted Drug Product placed under corresponding conditions listed in Table 17 to investigate their stability.

[0709] Methods: The same methods were used in this study as for the equivalent methods in the lyophilization confirmation study above.

[0710] Appearance, pH and protein concentration:

[0711] As shown in this study, for the reconstituted Compound 1 Drug Product, after 6 hours of storage at room temperature or 24 hours of storage at 2-8°C, no substantial change of appearance, pH and protein concentration was observed compared to TO.

[0712] Table 17: Data summary of appearance, pH and protein concentration in reconstitution stability study SEC-HPLC: The SEC-HPLC results are shown in Table 18. For the reconstituted Compound 1 DP, after 6 hours of storage at room temperature or 24 hours of storage at 2-8°C, no substantial change of SEC-HPLC was observed compared with TO.

[0713] Table 18: Results of SEC-HPLC in reconstitution stability study clEF: The clEF results are shown in Table 19. For the reconstituted Compound 1 DP, after 6 hours of storage at room temperature or 24 hours of storage at 2-8°C, no substantial change of clEF was observed compared to TO.

[0714] Table 19: Results of clEF in reconstitution stability study

[0715] HI AC: The results are shown in Table 20. For the reconstituted Compound 1 Drug Product, after 6 hours of storage at room temperature or 24 hours of storage at 2-8°C, no substantial increase of sub-visible particles was observed compared with TO.

[0716] Table 20: Results of HIAC in reconstitution stability study

[0717] Drug-Antibody Ratio (DAR): The DAR results are shown in Table 21. For the reconstituted Compound 1 Drug Product, after 6 hours of storage at room temperature or 24 hours of storage at 2-8°C, no substantial change of DAR was observed compared with TO. Table 21: Results of DAR in reconstitution stability study

[0718] The following additional studies were performed at the indicated time points:

[0719] Free drug stability study: no substantial changes in free drug were observed in the reconstituted Compound 1 Drug Product after the specified time periods.

[0720] Potency assay after storage and reconstitution: no substantial changes in biological activity were observed in the reconstitution stability study after the specified time periods.

[0721] Example 8b - Lyophilized composition Stability Study

[0722] Sample information: Compound 1 was formulated with 20.0 mg / mL Compound 1, 25 mM histidine, 9% (w / v) sucrose, 0.03% (w / v) polysorbate 80, pH 5.5.

[0723] Sample preparation: Drug substance solution was aseptically filtered, filled into glass vials, semi-stoppered and freeze-dried in a lyophilizer. All procedures were carried out in a biosafety hood.

[0724] Study Plan: Sampling and testing plan for the lyophilized composition confirmation study is shown in Table 22. For long-term, accelerated and stress conditions storage, samples were incubated at 2~8 °C, 25 °C and 40 °C, respectively. Samples at TO without any stress treatment were set as control. Testing items including appearance (before and after reconstitution), pH, protein concentration, SEC-HPLC, clEF, and sub-visible particles (HIAC) were performed in this study. At each sampling point, samples were retrieved and analyzed timely.

[0725] Table 22: Sampling and testing plan of lyophilized composition confirmation study

[0726] X=Appearance (before and after reconstitution), pH, protein concentration, SEC HPLC, clEF, DAR; Y=Sub-visible particles. Results and Discussion

[0727] Appearance, pH and protein concentration:

[0728] Appearance of all samples, including clarity, colour and visible particles, was observed visually against black and white background by using a YB-2 clarity detector, with the light intensity of 1000-1500 Lux.

[0729] Sample pH was measured by a pH meter with a glass electrode. The pH meter was calibrated by standard solutions of pH 4.01 , 7.00 and 9.21. Each sample was determined twice (100 pL sample each) and the average value was adopted in the report.

[0730] Protein concentration was determined by the absorbance of 280 nm and 370 nm using SoloVPE spectrophotometer. The extinction coefficient of Compound 1 mAb protein is 1.52 (mg / mL)-1cm1.

[0731] SoloVPE system is dependent on the variable path length Spectroscopy Technology. According to Beer’s law equation: A=E*L*C, where A=Absorbance, e=Extinction Coefficient, L=Path Length, C=Concentration, Slope m= A / L can be obtained by measuring the absorbance at 10 different path lengths. Through the curve of path length and absorbance, the slope m can be calculated. As C=m / e, with E and m known, the concentration can be calculated.

[0732] SEC-HPLC: The sample was diluted to 10.0 mg / mL with mobile phase, and 100 pg of sample was then injected into a TSKgel G3000SWXL column (7.8x300 mm, 5 pm Steel / TOSOH). The analysis was performed on the Agilent 1260 HPLC system with a MWD detector (detection wavelength: 280 nm and 370 nm). The chromatographic program was a 20 min isocratic gradient with mobile phase (50 mM Phosphate Buffer, 300 mM NaCI, pH 6.8 ± 0.1) : acetonitrile (can) = 9:1 (v / v)) at a flow rate of 1.0 mL / min.

[0733] CIEF: Compound 1 samples were mixed with master mixture to generate loading mixture, which contains 2.0 pL Pharmalyte 8-10.5, 2.0 pL Pharmalyte 3-10, 35 pL 1% MC, 0.5 pL pl marker 7.05, 0.5 pL pl marker 9.46, 37.5 pL 8M Urea solution, 0.15 pL Glacial Acetic Acid, 2.35 pL ultrapure water at a final protein concentration of 0.4 mg / mL. Place loading mixture in a 2~8 °C refrigerator or a 5°C heat block for more than 48 h. The test needs to be completed within 96 h after the samples being mixed with the master mix, otherwise the samples should be re-prepared. The loading mixture was loaded into a FC-Coated capillary, and analyzed with iCE3 Capillary Isoelectric Focusing Analyzer equipped with whole-column detection camera.

[0734] After the analysis, the raw data were processed with Empower 3.

[0735] Sub-visible particulate matter (HIAC): A HACH Particulate Analyzer was utilized to measure the sub-visible particle size and counts under a laminar flow cabinet. To avoid introducing air bubbles and interference during examination, all samples were held in the cabinet for at least 0.5 hour before testing. Each sample was tested for four consecutive runs, 0.45 mL each. The results were presented as average number of particles of >10 pm and >25 pm per mL (method conforms to USP <788> Particulate matter in injections).

[0736] The results are shown in Table 23 to Table25. For the appearance of the lyophilized cake, no substantial change of the appearance, pH, visible particle, subvisible particle, charge variants, SEC, DAR or protein concentration, was observed at any conditions, including 2-8 °C, 25 °C and 40 °C.

[0737] Table 23 Stability Data at 2-8 °C

[0738] Table 24 Stability Data at 25 °C

[0739] Table 25 Stability Data at 40 °C

[0740] Summary: In this study, Compound 1 protein was lyophilized with the final lyophilization process, and its stability was investigated after 24 months of storage at 2-8°C, or 6 months of storage at 25°C, or 1 months of storage at 40°C. The above results showed that Compound 1 was stable in the selected lyophilized composition.

[0741] Summary

[0742] In this study, the stability of reconstituted Compound 1 Drug Product was investigated. After Compound 1 Drug Product was reconstituted and stored at 25°C for 6 hours or 2-8°C for 24 hours. No substantial change of the testing items was observed compared with TO.

[0743] According to the above results, reconstituted Compound 1 Drug Product was stable for 6 hours at room temperature and 24 hours at 2-8°C.

[0744] All samples were colourless, slightly opalescence and free of visible particles. No substantial change in protein concentration, pH and sub-visible particles was observed for all the tested samples during the lyophilization composition confirmation study.

[0745] For all critical quality attributes, no substantial change was observed after 12 weeks of incubation at 2~8 °C / 25 °C or 4 weeks incubation at 40 °C.

[0746] No substantial quality change was observed after reconstitution for the Compound 1 Drug Product over the times tested.

[0747] Taken together, the stability of Compound 1 in the selected composition has been confirmed.

[0748] Example 9a - A Phase III, Multicentre, Open-label, Randomized Study to Compare Compound 1 Versus Trastuzumab Emtasine (T-DM1 , Kadcyla®) in Patients With HER2- positive Unresectable / Metastatic Breast Cancer Who Have Been Treated With Trastuzumab and a Taxane

[0749] This is a randomized controlled, 2-arm, open-label, multicentre phase III study to assess the efficacy and safety of Compound 1 versus trastuzumab emtasine (T-DM1) in patients with HER2-positive unresectable / metastatic breast cancer who have been treated with trastuzumab and taxanes. Approximately 224 subjects with unresectable or metastatic HER2-positive breast cancer will be randomized 1 :1 to receive Compound 1 or trastuzumab emtasine, respectively. Table 26: Arms and Interventions

[0750] Outcome Measures

[0751] Primary Outcome Measure:

[0752] 1. Progression Free Survival (PFS) by Blinded Independent Central Review (BICR) assessment per Response Evaluation Criteria in Solid Tumours Version 1.1 (RECIST 1.1) - defined as the time from randomization to the first documented disease progression per RECIST 1.1 as assessed by BICR or death due to any cause, whichever occurs first [Time Frame: Up to approximately 24 months.]

[0753] Secondary Outcome Measures:

[0754] 2. Overall Survival (OS) - Defined as the time from randomization to death due to any cause. [Time Frame: Up to approximately 24 months.]

[0755] 3. Progression Free Survival (PFS) by Investigator assessment per RECIST 1.1 - defined as the time from randomization to the first documented disease progression per RECIST 1.1 as assessed by investigator or death due to any cause, whichever occurs first. [Time Frame: Up to approximately 24 months.]

[0756] 4. Objective response rate (ORR) by BICR and investigator assessment per RECIST 1.1 - Defined as the percentage of patients who have a complete response (CR) or partial response (PR) per RECIST 1.1 as assessed by BICR and investigator assessment. [Time Frame: Up to approximately 24 months.]

[0757] 5. Duration of response (DoR) by BICR and investigator assessment per RECIST 1.1- defined as the time from first response (CR or PR) to subsequent disease progression per RECIST 1.1 as assessed by BICR and investigator assessment, or death from any cause, whichever occurs first. [Time Frame: Up to approximately 24 months.]

[0758] 6. PK parameters: maximum observed concentration (Cmax) - Maximum observed concentration (Cmax) of Compound 1 and free Compound 2, etc. after Compound 1 administration [Time Frame: Up to approximately 24 months.]

[0759] 7. PK parameters: time to maximum concentration (Tmax) Time to maximum concentration (Tmax) of Compound 1 and free Compound 2, etc. after Compound 1 administration [Time Frame: Up to approximately 24 months.] 8. Adverse events (AEs) - Number and percentage of patients who report serious adverse events (SAEs), treatment-emergent adverse events (TEAEs), TEAEs leading to study drug discontinuation, adverse events of special interest (AESIs) (graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0[NCI-CTCAE v5.0]) [Time Frame: Up to approximately 24 months.]

[0760] 9. Patient reported outcomes (PROs): European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (QLQ) - C30 - Change from baseline in the functioning / symptom / global QoL subscales of EORTC QLQ-C30. Scale scores range from 0- 100. For functioning and global QoL scales, higher scores indicate better functioning or global health status. For symptom scales, higher scores indicate greater symptom burden. [Time Frame: Up to approximately 24 months.]

[0761] 10. Patient reported outcomes (PROs): EORTC QLQ-BR45 Change from baseline in the functioning / symptom subscales of EORTC QLQ-BR45. Scale scores range from 0-100. For functioning scales, higher scores indicate better functioning. For symptom scales, higher scores indicate greater symptom burden. [Time Frame: Up to approximately 24 months.]

[0762] 11. Patient reported outcomes (PROs): European Quality of Life Five Dimension Five Level Scale (EQ-5D-5L) - Change from baseline in EQ-5D-5L health state utility index score and Visual Analogue Scale ( AS) score. VAS score range from 0-100, higher scores indicate better health status. [Time Frame: Up to approximately 24 months.]

[0763] 12. European Quality of Life Five Dimension Five Level Scale (EQ-5D-5L) EQ-5D-5L health state utility index score and Visual Analogue Scale (VAS) score. The change from baseline value will be reported. [Time Frame: Up to approximately 24 months.]

[0764] 13. Anti-drug antibodies (ADA) - Number and percentage of patients who develop anti-drug antibody (ADA) for Compound 1. [Time Frame: Up to approximately 24 months.]

[0765] Eligibility

[0766] • Minimum Age: 18 Years

[0767] • Maximum Age: None

[0768] • Sex: All

[0769] • Gender Based: All

[0770] • Accepts Healthy Volunteers: No

[0771] Inclusion Criteria

[0772] • Male or female adults > 18 years at the time of voluntary signing of informed consent.

[0773] • Pathologically confirmed unresectable or metastatic HER2 positive breast cancer previously treated with trastuzumab and taxane • Eastern Cooperative Oncology Group (ECOG) performance status score is 0 or 1.

[0774] • Presence of at least one measurable lesion according to RECIST v1 .1

[0775] • Expected survival time > 12 weeks.

[0776] • Subjects must give informed consent to this study and voluntarily sign written informed consent form prior to the study.

[0777] Exclusion Criteria

[0778] • Prior anti-HER2 ADC therapy.

[0779] • Previous history of ILD / non-infectious pneumonitis / radiation pneumonitis requiring steroid therapy.

[0780] • Known serious hypersensitivity to the active ingredients of the study drug, inactive ingredients in the composition, or other antibody drugs.

[0781] • Multiple primary malignancies within 3 years, except for adequately resected nonmelanoma skin cancer, curatively treated in situ tumour, or contralateral breast cancer.

[0782] • Uncontrolled infection requiring intravenous antibiotics, antiviral or antifungal agents, autoimmune disease requiring treatment, uncontrolled diabetes, hypertension, or other systemic disease that makes compliance with study procedures difficult

[0783] • Unrecovered toxicity from prior anticancer therapy, defined as toxicity (except for alopecia) not recovered to <Grade 1 (NCI-CTCAE v5.0) or baseline.

[0784] Other protocol defined inclusion / exclusion criteria may apply.

[0785] Example 9b - Further Information - A Phase III, Multicentre, Open-label, Randomized Controlled Study to Evaluate Compound 1 Versus Trastuzumab Emtasine (T-DM1) in Patients With HER2- Positive Unresectable / Metastatic Breast Cancer Previously Treated with Trastuzumab and Taxanes

[0786] 1 . The purpose of the test

[0787] Primary objective: To compare the PFS benefits of Compound 1 with trastuzumab emtasine (T-DM1) in patients with HER2-positive unresectable / metastatic breast cancer who have received prior trastuzumab and taxane therapy. Secondary objectives: To compare the efficacy and safety of Compound 1 with T-DM1 , to analyze the PK of Compound 1 , to evaluate the improvement of disease symptoms and quality of life compared to trastuzumab emtasine (T-DM1), and to evaluate the immunogenicity of Compound 1. 2. Experimental design

[0788] Classification of effectiveness Staging of Stage Type of Parallel trials the trial III design grouping randomization randomization Blinding opening Scope of Domestic the test trials

[0789] 3. Subject information

[0790] Age: 18 years old (minimum age), no upper limit (Maximum age)

[0791] Gender: Male + Female

[0792] Healthy subjects: Not

[0793] Table 27: Inclusion criteria Table 28: Exclusion Criteria

[0794] 4. Test grouping

[0795] Investigational drug: Compound 1

[0796] Dosage form: lyophilized powder for injection

[0797] Specification: 100mg / bottle

[0798] Dosage: Intravenous infusion, 8 mg / kg

[0799] Dosage course: Subjects will continue to receive Compound 1 treatment according to the dosing regimen of Q3W (1 cycle) until unacceptable toxicity, death, PD, withdrawal of consent, or other discontinuation criteria are met

[0800] Comparator: Trastuzumab emtasine

[0801] Dosage form: lyophilized powder for injection Specification: 100mg / bottle

[0802] Dosage: Intravenous infusion, 3.6 mg / kg

[0803] Medication schedule: Subjects will continue to receive T-DM1 treatment according to the dosing regimen of Q3W (1 cycle), until unacceptable toxicity, death, PD, withdrawal of consent, or other discontinuation criteria are met

[0804] 5. Endpoint indicators

[0805] Table 29: The main endpoint indicators and evaluation time

[0806] Table 30: Secondary endpoint measures and evaluation time

[0807] All publications mentioned in the above specification are herein incorporated by reference. Various modifications and variations of the described methods and system of the invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention which are obvious to those skilled in molecular biology or related fields are intended to be within the scope of the following claims.

Claims

CLAIMS1. An antibody-drug conjugate having a structure shown as formula (I):or a pharmaceutically acceptable salt thereof, wherein:Ab is trastuzumab; a connection number Nais an integer from 1 to 10;I— iS " I— a- L b- l—c- ,-Lc- is -CH2-;X1is saturated C, and X1is substituted with Rn; ring A is selected from the group consisting of: 3-10 membered saturated or partially unsaturated heterocyclyl and 3-10 membered saturated or partially unsaturated carbocyclyl, wherein ring A is substituted with 0 or at least 1 substituent R1a; when ring A is 3-10 membered saturated or partially unsaturated carbocyclyl, ring A is substituted with p L2, and L2is not Rn; or, when ring A is 3-10 membered saturated or partially unsaturated heterocyclyl, ring A is substituted with p L2;L2is -R2-L3-, and R2is used for direct or indirect linking of a ligand;L3is -(C(R3a)(R3b))m-, wherein when L3comprises a methylene unit, 0 or at least 1 methylene unit of L3is independently replaced by -N(R4)C(O)-, -C(O)N(R4)-, -C(O)-, -OC(O)-, -C(O)O-, -NR4-, -0-, -S-, -SO-, -SO2-, -P(R4)-, -P(=O)(R4)-, -N(R4)SO2-, -SO2N(R4)-, -C(=S)-, -C(=NR4)- , -N=N-, -C=N-, -N=C- or -C(=N2)-;R2is selected from the group consisting of: -O-, -(R2a)N-, -S- and -P(=O)(R2a)-;L1is -(C(R5a)(R5b))n-, wherein when L1comprises a methylene unit, 0 or at least 1 methylene unit of L1is independently replaced by -N(R6)C(O)-, -C(O)N(R6)-, -C(O)-, -OC(O)-, -C(O)O-, - NR6-, -O-, -S-, -SO-, -SO2-, -P(R6)-, -P(=O)(R6)-, -N(R6)SO2-, -SO2N(R6)-, -C(=S)-, -C(=NR6)- , -N=N-, -C=N-, -N=C- or -C(=N2)-; wherein each R1a, each R2a, each R3a, each R3b, each R4, each R5a, each R5b, each R6and each Rnare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, - OR, -SR, -N(Ra)(Rb), -C(O)R, -CO2R, -C(O)C(O)R, -C(O)CH2C(O)R, -S(O)R, -S(O)2R, - C(O)N(Ra)(Rb), -SO2N(Ra)(Rb), -OC(O)R, -N(R)SO2R, or a Ci-6aliphatic group optionally substituted with R; wherein each R, each Raand each Rbare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, -OH, -SH, -NH2, -C(O)H, -CO2H, -C(O)C(O)H, - C(O)CH2C(O)H, -S(O)H, -S(O)2H, -C(O)NH2, -SO2NH2, -OC(O)H, -N(H)SO2H or a C1-6 aliphatic group; m and n are each independently selected from the group consisting of integers > 0, and p is an integer > 1 ; for use in a method of treating endometrial cancer.

2. An antibody-drug conjugate having a structure shown as formula (I):or a pharmaceutically acceptable salt thereof, wherein:Ab is trastuzumab; a connection number Nais an integer from 1 to 10;I— iS " I— a- L b- Lc- ,-Lc- is -CH2-;X1is saturated C, and X1is substituted with Rn; ring A is selected from the group consisting of: 3-10 membered saturated or partially unsaturated heterocyclyl and 3-10 membered saturated or partially unsaturated carbocyclyl, wherein ring A is substituted with 0 or at least 1 substituent R1a; when ring A is 3-10 membered saturated or partially unsaturated carbocyclyl, ring A is substituted with p L2, and L2is not Rn; or, when ring A is 3-10 membered saturated or partially unsaturated heterocyclyl, ring A is substituted with p L2;L2is -R2-L3-, and R2is used for direct or indirect linking of a ligand;L3is -(C(R3a)(R3b))m-, wherein when L3comprises a methylene unit, 0 or at least 1 methylene unit of L3is independently replaced by -N(R4)C(O)-, -C(O)N(R4)-, -C(O)-, -OC(O)-, -C(O)O-, - NR4-, -O-, -S-, -SO-, -SO2-, -P(R4)-, -P(=O)(R4)-, -N(R4)SO2-, -SO2N(R4)-, -C(=S)-, -C(=NR4)- , -N=N-, -C=N-, -N=C- or -C(=N2)-;R2is selected from the group consisting of: -O-, -(R2a)N-, -S- and -P(=O)(R2a)-;L1is -(C(R5a)(R5b))n-, wherein when L1comprises a methylene unit, 0 or at least 1 methylene unit of L1is independently replaced by -N(R6)C(O)-, -C(O)N(R6)-, -C(O)-, -OC(O)-, -C(O)O-, - NR6-, -O-, -S-, -SO-, -SO2-, -P(R6)-, -P(=O)(R6)-, -N(R6)SO2-, -SO2N(R6)-, -C(=S)-, -C(=NR6)- , -N=N-, -C=N-, -N=C- or -C(=N2)-; wherein each R1a, each R2a, each R3a, each R3b, each R4, each R5a, each R5b, each R6and each Rnare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, - OR, -SR, -N(Ra)(Rb), -C(O)R, -CO2R, -C(O)C(O)R, -C(O)CH2C(O)R, -S(O)R, -S(O)2R, - C(O)N(Ra)(Rb), -SO2N(Ra)(Rb), -OC(O)R, -N(R)SO2R, or a Ci-6aliphatic group optionally substituted with R; wherein each R, each Raand each Rbare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, -OH, -SH, -NH2, -C(O)H, -CO2H, -C(O)C(O)H, - C(O)CH2C(O)H, -S(O)H, -S(O)2H, -C(O)NH2, -SO2NH2, -OC(O)H, -N(H)SO2H or a C1-6 aliphatic group; m and n are each independently selected from the group consisting of integers > 0, and p is an integer > 1 ;or a pharmaceutically acceptable salt thereof, for use in a method of treating cancer, wherein the method comprises administering the antibody-drug conjugate or pharmaceutically acceptable salt thereof to a patient at a dose in the range of 2.2 mg / kg to 12.0 mg / kg.

3. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to claim 2, wherein the dose is in the range of 6.0 mg / kg to 10.0 mg / kg.

4. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to claim 2 or claim 3, wherein the patient has been determined to have a cancer which is a HER2 positive or HER2 overexpressive cancer.

5. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to claim 2 or claim 3, wherein the patient has been determined to have a cancer which is a HER2 low or HER2 negative cancer.

6. The antibody-drug conjugate or pharmaceutically acceptable salt thereof for use according to any one of claims 2-5, wherein the cancer is selected from the group consisting of lung cancer, kidney cancer, urinary tract carcinoma, colorectal cancer, prostatic cancer, glioblastoma multiforme, ovarian cancer, pancreatic cancer, breast cancer, melanoma, liver cancer, bladder cancer, stomach cancer, esophageal cancer and endometrial cancer.

7. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to claim 6, wherein the cancer is breast cancer.

8. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to claim 7, wherein the cancer is a HER2 positive breast cancer.

9. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to claim 7, wherein the cancer is a HER2 low or HER2 negative breast cancer.

10. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to claim 6, wherein the cancer is endometrial cancer.

11. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to claim 10, wherein the cancer is a HER2 positive endometrial cancer.

12. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to claim 10, wherein the cancer is a HER2 low or HER2 negative endometrial cancer.

13. An antibody-drug conjugate having a structure shown as formula (I):or a pharmaceutically acceptable salt thereof, wherein:Ab is trastuzumab; a connection number Nais an integer from 1 to 10;I— iS " I— a- L b- l—c- ,-Lc- is -CH2-;X1is saturated C, and X1is substituted with Rn; ring A is selected from the group consisting of: 3-10 membered saturated or partially unsaturated heterocyclyl and 3-10 membered saturated or partially unsaturated carbocyclyl, wherein ring A is substituted with 0 or at least 1 substituent R1a; when ring A is 3-10 membered saturated or partially unsaturated carbocyclyl, ring A is substituted with p L2, and L2is not Rn; or, when ring A is 3-10 membered saturated or partially unsaturated heterocyclyl, ring A is substituted with p L2;L2is -R2-L3-, and R2is used for direct or indirect linking of a ligand;L3is -(C(R3a)(R3b))m-, wherein when L3comprises a methylene unit, 0 or at least 1 methylene unit of L3is independently replaced by -N(R4)C(O)-, -C(O)N(R4)-, -C(O)-, -OC(O)-, -C(O)O-, - NR4-, -O-, -S-, -SO-, -SO2-, -P(R4)-, -P(=O)(R4)-, -N(R4)SO2-, -SO2N(R4)-, -C(=S)-, -C(=NR4)- , -N=N-, -C=N-, -N=C- or -C(=N2)-;R2is selected from the group consisting of: -O-, -(R2a)N-, -S- and -P(=O)(R2a)-;L1is -(C(R5a)(R5b))n-, wherein when L1comprises a methylene unit, 0 or at least 1 methylene unit of L1is independently replaced by -N(R6)C(O)-, -C(O)N(R6)-, -C(O)-, -OC(O)-, -C(O)O-, - NR6-, -O-, -S-, -SO-, -SO2-, -P(R6)-, -P(=O)(R6)-, -N(R6)SO2-, -SO2N(R6)-, -C(=S)-, -C(=NR6)- , -N=N-, -C=N-, -N=C- or -C(=N2)-; wherein each R1a, each R2a, each R3a, each R3b, each R4, each R5a, each R5b, each R6and each Rnare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, - OR, -SR, -N(Ra)(Rb), -C(O)R, -CO2R, -C(O)C(O)R, -C(O)CH2C(O)R, -S(O)R, -S(O)2R, - C(O)N(Ra)(Rb), -SO2N(Ra)(Rb), -OC(O)R, -N(R)SO2R, or a Ci-6aliphatic group optionally substituted with R; wherein each R, each Raand each Rbare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, -OH, -SH, -NH2, -C(O)H, -CO2H, -C(O)C(O)H, - C(O)CH2C(O)H, -S(O)H, -S(O)2H, -C(O)NH2, -SO2NH2, -OC(O)H, -N(H)SO2H or a C1-6 aliphatic group; m and n are each independently selected from the group consisting of integers > 0, and p is an integer > 1 ; for use in a method of treating breast cancer in a patient previously treated with an anti- HER2 antibody and / or a taxane.

14. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to claim 13, wherein the anti-HER2 antibody is selected from the group consisting of trastuzumab, pertuzumab and margetuximab, or a biosimilar of any thereof.

15. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to claim 14, wherein the anti-HER2 antibody is trastuzumab, or a biosimilar thereof.

16. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to any one of claims 13-15, wherein the taxane is selected from the group consisting of paclitaxel, docetaxel, cabazitaxel, and nab-paclitaxel.

17. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to any one of claims 13-16, wherein the cancer is a HER2 positive breast cancer.

18. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to any one of claims 13-17, wherein the cancer is unresectable breast cancer.

19. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to any one of claims 13-18, wherein the cancer is metastatic breast cancer.

20. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to any one of claims 13-16, wherein the cancer is a HER2 positive unresectable or metastatic breast cancer.

21. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to any one of claims 1-20, wherein ring A is 4 membered saturated carbocyclyl.

22. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to any one of claims 1-21 , wherein ring A is substituted with 1 L2.

23. The antibody-drug conjugate, or the pharmaceutically acceptable salt thereof, for use according to any one of claims 1-22, wherein m is 0, and L3is a covalent bond.

24. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to any one of claims 1-23, wherein n is 1, and L1is -C(R5a)(R5b)- wherein 1 methylene unit of L1is replaced by -C(O)-.

25. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to any one of claims 1-24, wherein the drug moiety has the following structure l-A:wherein R2is as defined in claim 1.

26. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to any one of claims 1-25, wherein the antibody-drug conjugate is Compound 1 having the structure below:Compound 1 , or pharmaceutically acceptable salt thereof, wherein Narepresents a connection number, and Nais selected from the group consisting of integers from 7 to 8.

27. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to claim 1 , wherein the antibody-drug conjugate or pharmaceutically acceptable salt thereof is administered at a dose in the range of 2.2 mg / kg to 12.0 mg / kg.

28. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to claim 27, wherein the wherein the dose is in the range of 6.0 mg / kg to 10.0 mg / kg.

29. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to any one of claims 1-28, wherein the antibody-drug conjugate or pharmaceutically acceptable salt thereof is administered at a dose of 8.0 mg / kg.

30. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to any one of claims 1-29, wherein the antibody-drug conjugate, or pharmaceutically acceptable salt thereof is administered once every three weeks.

31. The antibody-drug conjugate, or pharmaceutically acceptable salt thereof, for use according to any one of claims 1-30, wherein the antibody-drug conjugate or pharmaceutically acceptable salt thereof is formulated as a composition comprising: about 20mg / ml antibody-drug conjugate or pharmaceutically acceptable salt thereof; about 25 mM histidine or a pharmaceutically acceptable salt thereof; about 9% (w / v) sucrose; andabout 0.03% (w / v) polysorbate 80, and wherein the pH of the composition is about 5.5.

32. A composition comprising: about 20mg / ml of an antibody-drug conjugate having a structure shown as formula (I):or a pharmaceutically acceptable salt thereof, wherein:Ab is trastuzumab; a connection number Nais an integer from 1 to 10;.I— is - La- Lb- Lc- ,-Lc- is -CH2-;X1is saturated C, and X1is substituted with Rn; ring A is selected from the group consisting of: 3-10 membered saturated or partially unsaturated heterocyclyl and 3-10 membered saturated or partially unsaturated carbocyclyl, wherein ring A is substituted with 0 or at least 1 substituent R1a; when ring A is 3-10 membered saturated or partially unsaturated carbocyclyl, ring A is substituted with p L2, and L2is not Rn; or, when ring A is 3-10 membered saturated or partially unsaturated heterocyclyl, ring A is substituted with p L2;L2is -R2-L3-, and R2is used for direct or indirect linking of a ligand;L3is -(C(R3a)(R3b))m-, wherein when L3comprises a methylene unit, 0 or at least 1 methylene unit of L3is independently replaced by -N(R4)C(O)-, -C(O)N(R4)-, -C(O)-, -OC(O)-, -C(O)O-, - NR4-, -O-, -S-, -SO-, -SO2-, -P(R4)-, -P(=O)(R4)-, -N(R4)SO2-, -SO2N(R4)-, -C(=S)-, -C(=NR4)- , -N=N-, -C=N-, -N=C- or -C(=N2)-;R2is selected from the group consisting of: -O-, -(R2a)N-, -S- and -P(=O)(R2a)-;L1is -(C(R5a)(R5b))n-, wherein when L1comprises a methylene unit, 0 or at least 1 methylene unit of L1is independently replaced by -N(R6)C(O)-, -C(O)N(R6)-, -C(O)-, -OC(O)-, -C(O)O-, - NR6-, -O-, -S-, -SO-, -SO2-, -P(R6)-, -P(=O)(R6)-, -N(R6)SO2-, -SO2N(R6)-, -C(=S)-, -C(=NR6)- , -N=N-, -C=N-, -N=C- or -C(=N2)-; wherein each R1a, each R2a, each R3a, each R3b, each R4, each R5a, each R5b, each R6and each Rnare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, - OR, -SR, -N(Ra)(Rb), -C(O)R, -CO2R, -C(O)C(O)R, -C(O)CH2C(O)R, -S(O)R, -S(O)2R, - C(O)N(Ra)(Rb), -SO2N(Ra)(Rb), -OC(O)R, -N(R)SO2R, or a Ci-6aliphatic group optionally substituted with R; wherein each R, each Raand each Rbare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, -OH, -SH, -NH2, -C(O)H, -CO2H, -C(O)C(O)H, - C(O)CH2C(O)H, -S(O)H, -S(O)2H, -C(O)NH2, -SO2NH2, -OC(O)H, -N(H)SO2H or a C1-6 aliphatic group; m and n are each independently selected from the group consisting of integers > 0, and p is an integer > 1 ; about 25 mM histidine or a pharmaceutically acceptable salt thereof; about 9% (w / v) sucrose; and about 0.03% (w / v) polysorbate 80, wherein the pH of the composition is about 5.5.

33. A composition comprising: about 20mg / ml of an antibody-drug conjugate having a structure shown as formula (I):or a pharmaceutically acceptable salt thereof, wherein:Ab is trastuzumab; a connection number Nais an integer from 1 to 10;.I— iS "I— a"l— b"l—c",-Lc- is -CH2-;X1is saturated C, and X1is substituted with Rn; ring A is selected from the group consisting of: 3-10 membered saturated or partially unsaturated heterocyclyl and 3-10 membered saturated or partially unsaturated carbocyclyl, wherein ring A is substituted with 0 or at least 1 substituent R1a; when ring A is 3-10 membered saturated or partially unsaturated carbocyclyl, ring A is substituted with p L2, and L2is not Rn; or, when ring A is 3-10 membered saturated or partially unsaturated heterocyclyl, ring A is substituted with p L2;L2is -R2-L3-, and R2is used for direct or indirect linking of a ligand;L3is -(C(R3a)(R3b))m-, wherein when L3comprises a methylene unit, 0 or at least 1 methylene unit of L3is independently replaced by -N(R4)C(O)-, -C(O)N(R4)-, -C(O)-, -OC(O)-, -C(O)O-, - NR4-, -O-, -S-, -SO-, -SO2-, -P(R4)-, -P(=O)(R4)-, -N(R4)SO2-, -SO2N(R4)-, -C(=S)-, -C(=NR4)- , -N=N-, -C=N-, -N=C- or -C(=N2)-;R2is selected from the group consisting of: -O-, -(R2a)N-, -S- and -P(=O)(R2a)-;L1is -(C(R5a)(R5b))n-, wherein when L1comprises a methylene unit, 0 or at least 1 methylene unit of L1is independently replaced by -N(R6)C(O)-, -C(O)N(R6)-, -C(O)-, -OC(O)-, -C(O)O-, - NR6-, -O-, -S-, -SO-, -SO2-, -P(R6)-, -P(=O)(R6)-, -N(R6)SO2-, -SO2N(R6)-, -C(=S)-, -C(=NR6)- , -N=N-, -C=N-, -N=C- or -C(=N2)-; wherein each R1a, each R2a, each R3a, each R3b, each R4, each R5a, each R5b, each R6and each Rnare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -CN, - OR, -SR, -N(Ra)(Rb), -C(O)R, -CO2R, -C(O)C(O)R, -C(O)CH2C(O)R, -S(O)R, -S(O)2R, - C(O)N(Ra)(Rb), -SO2N(Ra)(Rb), -OC(O)R, -N(R)SO2R, or a Ci-6aliphatic group optionally substituted with R; wherein each R, each Raand each Rbare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -CN, -OH, -SH, -NH2, -C(O)H, -CO2H, -C(O)C(O)H, - C(O)CH2C(O)H, -S(O)H, -S(O)2H, -C(O)NH2, -SO2NH2, -OC(O)H, -N(H)SO2H or a C1-6 aliphatic group; m and n are each independently selected from the group consisting of integers > 0, and p is an integer > 1 ; about 0.82 mg / ml L-histidine; about 4.14 mg / ml L-histidine hydrochloride monohydrate; about 90 mg / ml sucrose; and about 0.3 mg / ml polysorbate 80.

34. A lyophilized composition comprising:(a) about 100mg of an antibody-drug conjugate having a structure shown as formula (I):or a pharmaceutically acceptable salt thereof, wherein:Ab is trastuzumab; a connection number Nais an integer from 1 to 10;.L is -La-Lb-Lc-,-Lc- is -CH2-;X1is saturated C, and X1is substituted with Rn; ring A is selected from the group consisting of: 3-10 membered saturated or partially unsaturated heterocyclyl and 3-10 membered saturated or partially unsaturated carbocyclyl, wherein ring A is substituted with 0 or at least 1 substituent R1a; when ring A is 3-10 membered saturated or partially unsaturated carbocyclyl, ring A is substituted with p L2, and L2is not Rn; or, when ring A is 3-10 membered saturated or partially unsaturated heterocyclyl, ring A is substituted with p L2;L2is -R2-L3-, and R2is used for direct or indirect linking of a ligand;L3is -(C(R3a)(R3b))m-, wherein when L3comprises a methylene unit, 0 or at least 1 methylene unit of L3is independently replaced by -N(R4)C(O)-, -C(O)N(R4)-, -C(O)-, -OC(O)-, -C(O)O-, - NR4-, -O-, -S-, -SO-, -SO2-, -P(R4)-, -P(=O)(R4)-, -N(R4)SO2-, -SO2N(R4)-, -C(=S)-, -C(=NR4)- , -N=N-, -C=N-, -N=C- or -C(=N2)-;R2is selected from the group consisting of: -O-, -(R2a)N-, -S- and -P(=O)(R2a)-;L1is -(C(R5a)(R5b))n-, wherein when L1comprises a methylene unit, 0 or at least 1 methylene unit of L1is independently replaced by -N(R6)C(O)-, -C(O)N(R6)-, -C(O)-, -OC(O)-, -C(O)O-, - NR6-, -O-, -S-, -SO-, -SO2-, -P(R6)-, -P(=O)(R6)-, -N(R6)SO2-, -SO2N(R6)-, -C(=S)-, -C(=NR6)- , -N=N-, -C=N-, -N=C- or -C(=N2)-; wherein each R1a, each R2a, each R3a, each R3b, each R4, each R5a, each R5b, each R6and each Rnare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, - OR, -SR, -N(Ra)(Rb), -C(O)R, -CO2R, -C(O)C(O)R, -C(O)CH2C(O)R, -S(O)R, -S(O)2R, - C(O)N(Ra)(Rb), -SO2N(Ra)(Rb), -OC(O)R, -N(R)SO2R, or a Ci-6aliphatic group optionally substituted with R; wherein each R, each Raand each Rbare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, -OH, -SH, -NH2, -C(O)H, -CO2H, -C(O)C(O)H, - C(O)CH2C(O)H, -S(O)H, -S(O)2H, -C(O)NH2, -SO2NH2, -OC(O)H, -N(H)SO2H or a C1-6 aliphatic group; m and n are each independently selected from the group consisting of integers > 0, and p is an integer > 1 ;(b) about 4.1 mg L-histidine;(c) about 20.7 mg L-histidine hydrochloride monohydrate;(d) about 450 mg sucrose; and(e) about 1.5 mg polysorbate 80.

35. A lyophilized composition comprising:(a) an antibody-drug conjugate having a structure shown as formula (I):or a pharmaceutically acceptable salt thereof, wherein:Ab is trastuzumab; a connection number Nais an integer from 1 to 10;L is -La-Lb-Lc-,-Lc- is -CH2-;X1is saturated C, and X1is substituted with Rn; ring A is selected from the group consisting of: 3-10 membered saturated or partially unsaturated heterocyclyl and 3-10 membered saturated or partially unsaturated carbocyclyl, wherein ring A is substituted with 0 or at least 1 substituent R1a; when ring A is 3-10 membered saturated or partially unsaturated carbocyclyl, ring A is substituted with p L2, and L2is not Rn;or, when ring A is 3-10 membered saturated or partially unsaturated heterocyclyl, ring A is substituted with p L2;L2is -R2-L3-, and R2is used for direct or indirect linking of a ligand;L3is -(C(R3a)(R3b))m-, wherein when L3comprises a methylene unit, 0 or at least 1 methylene unit of L3is independently replaced by -N(R4)C(O)-, -C(O)N(R4)-, -C(O)-, -OC(O)-, -C(O)O-, - NR4-, -O-, -S-, -SO-, -SO2-, -P(R4)-, -P(=O)(R4)-, -N(R4)SO2-, -SO2N(R4)-, -C(=S)-, -C(=NR4)- , -N=N-, -C=N-, -N=C- or -C(=N2)-;R2is selected from the group consisting of: -O-, -(R2a)N-, -S- and -P(=O)(R2a)-;L1is -(C(R5a)(R5b))n-, wherein when L1comprises a methylene unit, 0 or at least 1 methylene unit of L1is independently replaced by -N(R6)C(O)-, -C(O)N(R6)-, -C(O)-, -OC(O)-, -C(O)O-, - NR6-, -O-, -S-, -SO-, -SO2-, -P(R6)-, -P(=O)(R6)-, -N(R6)SO2-, -SO2N(R6)-, -C(=S)-, -C(=NR6)- , -N=N-, -C=N-, -N=C- or -C(=N2)-; wherein each R1a, each R2a, each R3a, each R3b, each R4, each R5a, each R5b, each R6and each Rnare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, - OR, -SR, -N(Ra)(Rb), -C(O)R, -CO2R, -C(O)C(O)R, -C(O)CH2C(O)R, -S(O)R, -S(O)2R, - C(O)N(Ra)(Rb), -SO2N(Ra)(Rb), -OC(O)R, -N(R)SO2R, or a Ci-6aliphatic group optionally substituted with R; wherein each R, each Raand each Rbare each independently hydrogen, protium, deuterium, tritium, halogen, -NO2, -ON, -OH, -SH, -NH2, -C(O)H, -CO2H, -C(O)C(O)H, - C(O)CH2C(O)H, -S(O)H, -S(O)2H, -C(O)NH2, -SO2NH2, -OC(O)H, -N(H)SO2H or a C1-6 aliphatic group; m and n are each independently selected from the group consisting of integers > 0, and p is an integer > 1 ; in an amount of about 100 parts by weight;(b) L-histidine, in an amount of about 4.1 parts by weight, relative to 100 parts by weight (a);(c) L-histidine hydrochloride monohydrate; in an amount of about 20.7 parts by weight, relative to 100 parts by weight (a);(d) sucrose, in an amount of about 450 parts by weight, relative to 100 parts by weight (a); and(e) polysorbate 80, in an amount of about 1.5 parts by weight, relative to 100 parts by weight (a).

36. A method of preparing the composition of claim 31 , 32 or 33, the method comprising reconstituting the lyophilized composition of claim 34 or 35 with a diluent.

37. The method of claim 36, where the diluent is water.

38. The method of claim 37, where the water is Water For Injection (WFI).

39. A method of preparing the lyophilized composition of claim 34 or 35, the method comprising lyophilizing the composition of claim 31 , 32 or 33.

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