Combination therapies using CDK4 inhibitors and Anti-her2 therapeutic agents for use in the treatment of cancer

Abstract

This disclosure relates to combination therapies comprising a cyclin dependent kinase 4 (CDK4) inhibitor of Formula (I) disclosed herein, and a monoclonal antibody or an antibody-drug conjugate, optionally in further combination with an endocrine therapy agent, and associated methods of treatment, pharmaceutical compositions, and uses thereof.

Description

[0001] COMBINATION THERAPY USING CDK4 INHIBITORS FOR CANCER TREATMENTS

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] [1] This application claims priority to US Provisional Application No. 63 / 720,348, filed November 14, 2024, and US Provisional Application No. 63 / 676,031, filed July 26, 2024, the contents of each of which are incorporated herein in their entirety.

[0004] REFERENCE TO THE SEQUENCE LISTING

[0005] [2] This application contains a Sequence Listing which has been submitted electronically in .XML format and is hereby incorporated by reference in its entirety. The .XML copy, created on July 16, 2025, is named “01218-0050-00PCT.xml” and is 46,283 bytes in size. The sequence listing contained in this .XML file is part of the specification and is hereby incorporated by reference herein in its entirety.

[0006] FIELD

[0007] [3] The present disclosure relates to combination therapies useful for treating cancer. In particular, the disclosure relates to combination therapies which comprise administering a CDK4 inhibitor in combination with an anti-HER2 monoclonal antibody or an anti-HER2 antibody drug-conjugate (‘ADC’), optionally in further combination with an additional an endocrine therapy agent. The disclosure also relates to associated methods of treatment, pharmaceutical compositions, and pharmaceutical uses.

[0008] BACKGROUND

[0009] [4] Cyclin-dependent kinases (CDKs) and related serine / threonine protein kinases are important cellular enzymes that perform essential functions in regulating cell division and proliferation. The CDK catalytic units are activated by regulatory subunits known as cyclins. At least sixteen mammalian cyclins have been identified (Johnson DG, Walker CL. Cyclins and Cell Cycle Checkpoints. Annu. Rev. Pharmacol. Toxicol. (1999) 39:295-312). Cyclin B / CDK1 , cyclin A / CDK2, cyclin E / CDK2, cyclin D / CDK4, cyclin D / CDK6, and likely other heterodynes are important regulators of cell cycle progression. Additional functions of cyclin / CDK heterodynes include regulation of transcription, DNA repair, differentiation and apoptosis (Morgan DO, Cyclin-dependent kinases: engines, clocks, and microprocessors. Annu. Rev. Cell. Dev. Biol. (1997) 13:261-291).

[0010] [5] CDK4 / 6 inhibitors, including palbociclib, ribociclib and abemaciclib, have been approved for treatment of hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative (HR+ / HER2-) advanced or metastatic breast cancer in combination with endocrine therapy, based on enhanced efficacy in prolonging PFS when compared to patients treated with endocrine therapy alone (Serra et al, Palbociclib in metastatic breast cancer: current evidence and real-life data, Drugs Context. (2019), 8:212579).

[0011] [6] CDK4 / 6 inhibitors have demonstrated substantial clinical effectiveness in treating HRpositive, HER2-negative advanced or metastatic breast cancer. However, similar to other kinase-targeting drugs, their efficacy may diminish over time due to the emergence of primary or acquired resistance. A notable limitation is that neutropenia, being a common adverse event, can interrupt treatment and require dose reductions. This highlights the need for therapies that can maintain efficacy while minimizing adverse effects.

[0012] [7] Currently, PF-07220060, a novel CDK4 selective inhibitor, is under clinical investigation. This compound offers a more selective inhibition profile, potentially translating into a reduced risk of neutropenia and other side effects associated with CDK6 inhibition.

[0013] [8] Despite the advancements in CDK4 inhibitor development, there remains a significant need for improved combination therapies for the treatment of cancers. The combinations, methods and uses of the present disclosure are believed to have one or more advantages, such as greater efficacy than treatment with either therapeutic agent alone; potential to reduce drug-drug interactions; potential to enable an improved dosing schedule; potential to reduce side effects; potential to overcome resistance mechanisms and the like.

[0014] SUMMARY

[0015] [9] This present disclosure relates to methods, combinations, uses, pharmaceutical compositions and kits for treating cancer, comprising a CDK4 inhibitor in combination with an anti-HER2 monoclonal antibody or an anti-HER2 antibody-drug conjugate, optionally in further combination with an additional anti-cancer agent.

[0016]

[0010] According to a first embodiment of the disclosure, there is provided a method of treating cancer in a subject in need thereof comprising administering to the subject a CDK4 inhibitor in combination with an anti-HER2 therapeutic agent comprising a monoclonal antibody or an antibody-drug conjugate (ADC); and optionally with an endocrine therapy agent; wherein the CDK4 inhibitor is a compound of Formula (I) or a pharmaceutically acceptable salt thereof:

[0017] wherein:

[0018] R1is H, F, or Cl;

[0019] R2is C1-C4 alkyl, where said C1-C4 alkyl is optionally substituted by R5;

[0020] R3is H or C1-C4 alkyl, where said C1-C4 alkyl is optionally substituted by R6;

[0021] R4is H or F; and each of R5and R6is independently OH, F, or C1-C2 alkoxy; wherein the monoclonal antibody is trastuzumab (Herceptin®), trastuzumab-qyyp (Trazimera®), pertuzumab (Perjeta®), margetuximab (Margenza®), zanidatamab, zenocutuzumab, or combinations thereof; wherein the ADC has the general formula Ab-(Linker-D)p, in which Ab represents the antibody or functional fragments thereof (e.g., Ab1 , Ab2 described herein), Linker represents a linker described herein, D represents a drug payload described herein, and p is 1 to 8 (e.g., 1 to 4).

[0011] In some embodiments, the ADC has the formula: wherein Ab1 is an antibody that binds to HER2 and comprises:

[0022] (1) a heavy chain variable region comprising a CDR-H1 , CDR-H2, and CDR-H3, wherein the CDR-H1 , CDR-H2, and CDR-H3 comprise the amino acid sequences of SEQ ID NOs: 2, 3, and 4, respectively; and

[0023] (2) a light chain variable region comprising a CDR-L1 , CDR-L2, and CDR-L3, wherein the CDR-L1 , CDR-L2, and CDR-L3 comprise the amino acid sequences of SEQ ID NOs: 8, 9, and 10, respectively; and wherein p is 1 to 4.

[0012] In some embodiments, the ADC comprises Ab2 which is conjugated with a drug payload (D2) via a linker (Linker2), wherein Ab2 is an antibody that binds to HER2 and comprises:

[0024] (1) a heavy chain variable region comprising a CDR-H1, CDR-H2, and CDR-H3, in which the CDR-H1 comprises the amino acid sequence of SEQ ID NO: 31, the CDR-H2 comprises the amino acid sequence of SEQ ID NO: 33, and the CDR-H3 comprises the amino acid sequence of SEQ ID NO: 34 or 35; and

[0025] (2) a light chain variable region comprising a CDR-L1, CDR-L2, and CDR-L3, in which the CDR-L1 , CDR-L2, and CDR-L3 comprise the amino acid sequences of SEQ ID NOs: 36, 37 and 38, respectively; wherein D2 is selected from MMAE and MMAF; and wherein Linker2 is linked with Ab2, optionally through thiol, and Linker2 is selected from mc-vc-pAB and me.

[0026]

[0013] According to another embodiment of the disclosure, provided herein is a method of treating cancer in a subject in need thereof comprising administering to the subject: an amount of a CDK4 inhibitor that is 1,5-anhydro-3-({5-chloro-4-[4-fluoro-2-(2- hydroxypropan-2-yl)-1-(propan-2-yl)-1 / 7-benzimidazol-6-yl]pyrimidin-2-yl}amino)-2,3-dideoxy-D- f / ireo-pentitol or a pharmaceutically acceptable salt thereof; and an amount of an anti-HER2 therapeutic agent that is an antibody-drug conjugate (ADC) that has the formula: wherein Ab1 is an antibody that binds to HER2 and comprises a heavy chain comprising the amino acid sequence of SEQ ID NO: 6 or 14, and comprises a light chain comprising the amino acid sequence of SEQ ID NO: 12, 16, 45, or 46, wherein p is 4, and optionally wherein the amounts together are effective in treating the cancer.

[0027]

[0014] According to still another embodiment of the disclosure, provided herein is a method of treating cancer in a subject in need thereof comprising administering to the subject: an amount of a CDK4 inhibitor that is 1,5-anhydro-3-({5-chloro-4-[4-fluoro-2-(2- hydroxypropan-2-yl)-1-(propan-2-yl)-1 / 7-benzimidazol-6-yl]pyrimidin-2-yl}amino)-2,3-dideoxy-D- f / ireo-pentitol or a pharmaceutically acceptable salt thereof; and an amount of an anti-HER2 therapeutic agent that is an antibody-drug conjugate (ADC) that comprises Ab2 which is conjugated with MMAE via mc-vc-pAB, wherein Ab2 is an antibody that binds to HER2 and comprises a heavy chain comprising the amino acid sequence of SEQ ID NO: 41 or 42, and comprises a light chain comprising the amino acid sequence of SEQ ID NO: 43, and optionally wherein the amounts together are effective in treating the cancer.

[0028] BRIEF DESCRIPTION OF THE DRAWINGS

[0029]

[0015] FIG. 1 illustrates the structure of the anti-HER2 immunoglobulin G1 ADC, T(kK183C+K290C)-vc0101 (PF-06804103), which comprises the anti-HER2 antibody T(kK183C+K290C) and 0101 payload connected via a vc linker. Each black circle represents a linker / payload that is conjugated to the monoclonal antibody. The underlined entity denotes the specific amino acid residue on the antibody to which conjugation occurs.

[0030]

[0016] FIG. 2 illustrates the structure of an ADC according to certain embodiments of the present description. As shown is RC48-vc-MMAE (disitamab vedotin (DV)) , an embodiment of ADC2.

[0031]

[0017] FIG. 3 illustrates the structure of an ADC according to certain embodiments of the present description. As shown is RC48-vc-MMAF, an embodiment of ADC2.

[0032]

[0018] FIG. 4 illustrates the structure of an ADC according to certain embodiments of the present description. As shown is RC48-mc-MMAF, an embodiment of ADC2.

[0033]

[0019] FIG. 5 shows dose-dependent growth inhibition by Trazimera, palbociclib, PF-07220060 as single agents, combination of palbociclib + Trazimera, and enhanced growth inhibition by combination of PF-07220060 + Trazimera, in HR+ HER2+ BT474 breast cancer spheroid in vitro growth as spheroid diameter (pm) versus time of treatment.

[0034]

[0020] FIG. 6 illustrates the effect of sequential treatment of the combination of a CDK inhibitor (PF-07220060 or palbociclib) and an antibody drug conjugate according to one embodiment of the present disclosure (anti-HER2-ADC PF-06804103), as compared to single agent treatments with palbociclib, PF-07220060, and PF-06804103, in HR+ HER2+ BT474 breast cancer spheroid in vitro growth as spheroid diameter (pm) versus time of treatment.

[0035]

[0021] FIG. 7 illustrates the schematic of an assay and sequential dosing procedure for a CDK inhibitor and an anti-HER2-ADC, disitamab vedotin (DV), according to certain embodiments of the present disclosure.

[0022] FIGs. 8A-8C show the dose response curves illustrating the single agent activity of PF- 07220060 (FIG.8A) and DV (FIG. 8B), along with the combined effect of DV + PF-07220060 (FIG. 8C).

[0036]

[0023] FIG. 9 shows an isobologram for CAMA1 cells treated with PF-07220060 and DV in vitro.

[0037] DETAILED DESCRIPTION

[0038]

[0024] The present disclosure may be understood more readily by reference to the following detailed description of the embodiments and preferred embodiments of the disclosure. It is to be understood that the terminology used herein is for the purpose of describing specific embodiments only and is not intended to be limiting. It is further to be understood that unless specifically defined herein, the terminology used herein is to be given its traditional meaning as known in the relevant art.

[0039]

[0025] E1. A method of treating cancer in a subject in need thereof comprising administering to the subject an amount of a CDK4 inhibitor in combination with an amount of an anti-HER2 therapeutic agent selected from the group consisting of (1) a monoclonal antibody or (2) an antibody-drug conjugate; and optionally with an endocrine therapy agent; wherein the CDK4 inhibitor is a compound of Formula (I): wherein:

[0040] R1is H, F, or Cl;

[0041] R2is C1-C4 alkyl, where said C1-C4 alkyl is optionally substituted by R5;

[0042] R3is H or C1-C4 alkyl, where said C1-C4 alkyl is optionally substituted by R6;

[0043] R4is H or F; and each of R5and R6is independently OH, F, or C1-C2 alkoxy; wherein the monoclonal antibody is trastuzumab (Herceptin®), trastuzumab-qyyp (Trazimera®), pertuzumab (Perjeta®), margetuximab (Margenza®), zanidatamab, zenocutuzumab, or combinations thereof. wherein the antibody-drug conjugate is selected from ADC1 or ADC2: wherein ADC1 has the formula: wherein Ab1 is an antibody that binds to HER2 and comprises:

[0044] (1) a heavy chain variable region comprising a CDR-H1, CDR-H2, and CDR-H3, wherein the CDR-H1 , CDR-H2, and CDR-H3 comprise the amino acid sequences of SEQ ID NOs: 2, 3, and 4, respectively; and

[0045] (2) a light chain variable region comprising a CDR-L1, CDR-L2, and CDR-L3, wherein the CDR-L1, CDR-L2, and CDR-L3 comprise the amino acid sequences of SEQ ID NOs: 8, 9, and 10, respectively; and wherein p is 1 to 4; wherein ADC2 comprises Ab2 which is conjugated with a drug payload (D2) via a linker (Linker2), wherein Ab2 is an antibody that binds to HER2 and comprises:

[0046] (1) a heavy chain variable region comprising a CDR-H1, CDR-H2, and CDR-H3, in which the CDR-H1 comprises the amino acid sequence of SEQ ID NO: 31, the CDR-H2 comprises the amino acid sequence of SEQ ID NO: 33, and the CDR-H3 comprises the amino acid sequence of SEQ ID NO: 34 or 35; and

[0047] (2) a light chain variable region comprising a CDR-L1 , CDR-L2, and CDR-L3, in which the CDR-L1 , CDR-L2, and CDR-L3 comprise the amino acid sequence of SEQ ID NOs: 36, 37, and 38, respectively; wherein D2 is selected from MMAE and MMAF; wherein Linker2 is linked with Ab2 through thiol and is selected from mc-vc-pAB and me; and wherein the amounts together are effective in treating cancer.

[0048]

[0026] E2. The method of embodiment E1 , wherein the compound of Formula (I) is 1 ,5- anhydro-3-({5-chloro-4-[4-fluoro-2-(2-hydroxypropan-2-yl)-1-(propan-2-yl)-1 / 7-benzimidazol-6- yl]pyrimidin-2-yl}amino)-2,3-dideoxy-D-f / 7reo-pentitol.

[0049]

[0027] E3. The method of any one of embodiments E1-E2, wherein the HER2 therapeutic agent is an antibody-drug conjugate which comprises Ab1 and p is 4.

[0050]

[0028] E4. The method of any one of embodiments E1-E2, wherein the HER2 therapeutic agent is an antibody-drug conjugate which comprises Ab2 which comprises:

[0051] (1) a heavy chain variable region comprising a CDR-H1, CDR-H2, and CDR-H3, in which the CDR-H1 comprises the amino acid sequence of SEQ ID NO: 31, the CDR-H2 comprises the amino acid sequence of SEQ ID NO: 33, and the CDR-H3 comprises the amino acid sequence of SEQ ID NO: 34 or 35; and

[0052] (2) a light chain variable region comprising a CDR-L1, CDR-L2, and CDR-L3, in which the CDR-L1 , CDR-L2, and CDR-L3 comprise the amino acid sequences of SEQ ID NOs: 36, 37, and 38, respectively;

[0053]

[0029] E5. The method of embodiment E4, wherein -Linker2-D2 is selected from the group consisting of vc-MMAE, vc-MMAF, and mc-MMAF.

[0054]

[0030] E6. The method of any one of embodiments E1-E2, wherein the anti-HER2 therapeutic agent is a monoclonal antibody selected from the group consisting of trastuzumab, trastuzumab-qyyp, pertuzumab, and margetuximab, zanidatamab, and zenocutuzumab.

[0055]

[0031] E7. The method of any one of embodiments E1-E3, wherein the anti-HER2 therapeutic agent is a monoclonal antibody which is trastuzumab-qyyp.

[0056]

[0032] E8. The method of embodiment E1 , wherein the compound of Formula (I) is 1 ,5- anhydro-3-({5-chloro-4-[4-fluoro-2-(2-hydroxypropan-2-yl)-1-(propan-2-yl)-1 / 7-benz-imidazol-6- yl]pyrimidin-2-yl}amino)-2,3-dideoxy-D-f / 7reo-pentitol, and wherein the anti-HER2 therapeutic agent is an antibody-drug conjugate which comprises Ab2 which comprises:

[0057] (1) a heavy chain variable region comprising a CDR-H1, CDR-H2, and CDR-H3, in which the CDR-H1 comprises the amino acid sequence of SEQ ID NO: 31, the CDR-H2 comprises the amino acid sequence of SEQ ID NO: 33, and the CDR-H3 comprises the amino acid sequence of SEQ ID NO: 34 or 35; and

[0058] (2) a light chain variable region comprising a CDR-L1, CDR-L2, and CDR-L3, in which the CDR-L1 , CDR-L2, and CDR-L3 comprise the amino acid sequences of SEQ ID NOs: 36, 37, and 38, respectively;

[0059]

[0033] E9. The method of embodiment E4, wherein -Linker2-D2 is selected from the group consisting of vc-MMAE, vc-MMAF, and mc-MMAF.

[0060]

[0034] E10. The method of any one of embodiments E1-E9, wherein the endocrine therapy agent is selected from the group consisting of letrozole, anastrozole, exemestane, fulvestrant, elacestrant, amcenestrant, giredestrant, RG6171, camizestrant, AZD9496, rintodestrant, ZN-c5, LSZ102, D-0502, LY3484356, SHR9549, tamoxifen, raloxifene, toremifene, lasofoxifene, bazedoxifene, and afimoxifene.

[0061]

[0035] E11. The method of claim any one of embodiments E1-E10, wherein the endocrine therapy agent is letrozole or fulvestrant.

[0062]

[0036] E12. The method of any one of embodiments E1-E11 , wherein the cancer is selected from the group consisting of prostate cancer, breast cancer, lung cancer, liver cancer, kidney cancer, bladder cancer, ovarian cancer, peritoneal cancer, fallopian tube cancer, cervical cancer, uterine cancer, pancreatic cancer, stomach cancer, colorectal cancer, esophageal cancer, head and neck cancer, testicular cancer, adrenal cancer, skin cancer, brain cancer, sarcoma, and lymphoma.

[0063]

[0037] E13. The method of any one of embodiments E1-E12, wherein the cancer is breast cancer selected from any one or more of: hormone receptor positive (HR+) breast cancer, hormone receptor negative (HR-) breast cancer, human epidermal growth factor receptor 2 negative (HER2-) breast cancer, human epidermal growth factor receptor 2 positive (HER2+) breast cancer, HR+ / HER2- breast cancer, estrogen receptor negative (ER-) / HR+ breast cancer, estrogen receptor positive (ER+) / HER2- breast cancer, and triple negative breast cancer (TNBC).

[0064]

[0038] E14. A combination for use in treating cancer comprising:

[0065] (i) a compound of Formula (I): or a pharmaceutically acceptable salt thereof, wherein:

[0066] R1is H, F, or Cl;

[0067] R2is C1-C4 alkyl, where said C1-C4 alkyl is optionally substituted by R5;

[0068] R3is H or C1-C4 alkyl, where said C1-C4 alkyl is optionally substituted by R6;

[0069] R4is H or F; and each R5and R6is independently OH, F or C1-C2 alkoxy; and

[0070] (ii) an antibody-drug conjugate having the formula: wherein Ab1 is an antibody that binds to HER2 and comprises:

[0071] (1) a heavy chain variable region comprising a CDR-H1 , CDR-H2, and CDR-H3, wherein the CDR-H1 , CDR-H2, and CDR-H3 comprise the amino acid sequences of SEQ ID NOs: 2, 3, and 4, respectively; and (2) a light chain variable region comprising a CDR-L1, CDR-L2, and CDR-L3, wherein the CDR-L1, CDR-L2, and CDR-L3 comprise the amino acid sequences of SEQ ID NOs: 8, 9, and 10, respectively; and wherein p is 1 to 4.

[0072]

[0039] E15. A combination for use in treating cancer comprising:

[0073] (i) a compound of Formula (I): or a pharmaceutically acceptable salt thereof, wherein:

[0074] R1is H, F, or Cl;

[0075] R2is C1-C4 alkyl, where said C1-C4 alkyl is optionally substituted by R5;

[0076] R3is H or C1-C4 alkyl, where said C1-C4 alkyl is optionally substituted by R6;

[0077] R4is H or F; and each R5and R6is independently OH, F or C1-C2 alkoxy; and

[0078] (ii) an antibody-drug conjugate comprising Ab2 which is conjugated with a drug payload (D2) via a linker (Linker2), wherein Ab2 is an antibody that binds to HER2 and comprises:

[0079] (1) a heavy chain variable region comprising a CDR-H1, CDR-H2, and CDR-H3, in which the CDR-H1 comprises the amino acid sequence of SEQ ID NO: 31, the CDR-H2 comprises the amino acid sequence of SEQ ID NO: 33, and the CDR-H3 comprises the amino acid sequence of SEQ ID NO: 34 or 35; and

[0080] (2) a light chain variable region comprising a CDR-L1, CDR-L2, and CDR-L3, in which the CDR-L1 , CDR-L2, and CDR-L3 comprise the amino acid sequences of SEQ ID NOs: 36, 37, and 38, respectively; wherein D2 is selected from MMAE and MMAF; and wherein Linker2 is linked with Ab2 through thiol and is selected from mc-vc-pAB and me.

[0081]

[0040] E16. The combination of any one of embodiments E14-E15, wherein the compound of Formula (I) is 1,5-anhydro-3-({5-chloro-4-[4-fluoro-2-(2-hydroxypropan-2-yl)-1-(propan-2-yl)-1 / 7- benz-imidazol-6-yl]pyrimidin-2-yl}amino)-2,3-dideoxy-D-f / 7reo-pentitol.

[0082]

[0041] E17. The combination of any one of embodiments E14-E16, wherein the cancer is selected from the group consisting of prostate cancer, breast cancer, lung cancer, liver cancer, kidney cancer, bladder cancer, ovarian cancer, peritoneal cancer, fallopian tube cancer, cervical cancer, uterine cancer, pancreatic cancer, stomach cancer, colorectal cancer, esophageal cancer, head and neck cancer, testicular cancer, adrenal cancer, skin cancer, brain cancer, sarcoma, and lymphoma.

[0083]

[0042] E18. The combination of any one of embodiments E14-E17, wherein the cancer is breast cancer selected from any one or more of: hormone receptor positive (HR+) breast cancer, hormone receptor negative (HR-) breast cancer, human epidermal growth factor receptor 2 negative (HER2-) breast cancer, human epidermal growth factor receptor 2 positive (HER2+) breast cancer, HR+ / HER2- breast cancer, estrogen receptor negative (ER-) / HR+ breast cancer, estrogen receptor positive (ER+) / HER2- breast cancer, and triple negative breast cancer (TNBC).

[0084]

[0043] Each of the embodiments of the present disclosure described herein may be combined with one or more other embodiments of the present disclosure described herein which is not inconsistent with the embodiment(s) with which it is combined. In addition, each of the embodiments below in the disclosure envisions within its scope the pharmaceutically acceptable salts of the compound disclosed.

[0085] Definitions

[0086]

[0044] Unless otherwise defined herein, scientific, and technical terms used in connection with the present disclosure have the meanings that are commonly understood by those of ordinary skill in the art.

[0087]

[0045] The invention described herein suitably may be practiced in the absence of any element(s) not specifically disclosed herein. Thus, for example, in each instance herein any of the terms "comprising", "consisting essentially of", and "consisting of" may be replaced with either of the other two terms.

[0088]

[0046] As used herein, the singular form "a", "an", and "the" include plural references unless indicated otherwise. For example, "a" substituent includes one or more substituents.

[0089]

[0047] As used herein, the term “about” when used to modify a numerically defined parameter means that the parameter may vary by as much as 10% below or above the stated numerical value for that parameter. For example, a dose of about 100 mg should be understood to mean that the dose may vary between 90 mg and 110 mg.

[0090]

[0048] As used herein, the terms “antibody-drug conjugate” or “ADC” refers to a molecule composed of an antibody linked to an anti-cancer drug. The antibody specifically binds to a certain tumor antigen, such as HER2. The antibodies used in an ADC may be full-length antibodies, antigen-binding fragments of a full-length antibody, or antibody derivatives. Typically, the anti-cancer drug is conjugated to the antibody via a linker. Thus, in one embodiment, the ADC provided by the present disclosure comprises an antibody, or antigenbinding fragment thereof, that binds to HER2, and a linker-drug moiety.

[0091]

[0049] As used herein, the term “HER2” refers to a transmembrane tyrosine kinase receptor that belongs to the EGFR family. HER2 is also known as ErbB2, p185 and CD340. This family of receptors includes four members (EGFR / HER1, HER2, HER3 and HER4) that function by stimulating growth factor signaling pathways such as the PI3K-AKT-mT0R pathway. Amplification and / or overexpression of HER2 is associated with multiple human malignancies. The wild type human HER2 protein is described, for example, in Semba et al., 1985, PNAS 82:6497-6501 and Yamamoto et al., 1986, Nature 319:230-4 and Genbank Accession Number X03363.

[0092]

[0050] The term “HER2” includes variants, isoforms, homologs, orthologs and paralogs. In some aspects of the disclosure, antibodies and antibody-drug conjugates cross-react with HER2 from species other than human, such as HER2 of mouse, rat, or primate, as well as different forms of HER2 (e.g., glycosylated HER2). In other aspects, the antibodies and antibody-drug conjugates may be completely specific for human HER2 and may not exhibit species or other types of cross-reactivity. As used herein the term HER2 refers to naturally occurring human HER2 unless contextually dictated otherwise. Therefore, a "HER2 antibody", “anti-HER2 antibody”, or other similar designation, means an antibody that associates, binds, or reacts with the HER2 type ligand or isoform, or fragment or derivative thereof. These terms are used interchangeably. Further, a "HER2 antibody-drug conjugate", “anti-HER2 antibody-drug conjugate” refers to an antibody-drug conjugate or ADC (as defined herein) that comprises an anti-HER2 antibody as defined herein. These terms are used interchangeably.

[0093]

[0051] Native or naturally occurring antibodies, and native immunoglobulins, are typically heterotetrameric glycoproteins of about 150,000 daltons, composed of two identical light (L) chains and two identical heavy (H) chains. Each light chain is linked to a heavy chain by one covalent disulfide bond, while the number of disulfide linkages varies among the heavy chains of different immunoglobulin isotypes. Each heavy and light chain also has regularly spaced intrachain disulfide bridges. Each heavy chain has at one end a variable domain (VH) followed by a number of constant domains. Each light chain has a variable domain at one end (VL) and a constant domain at its other end; the constant domain of the light chain is aligned with the first constant domain of the heavy chain, and the light chain variable domain is aligned with the variable domain of the heavy chain. The term “variable” refers to the fact that certain portions of the variable domains differ extensively in sequence among antibodies.

[0094]

[0052] As used herein, the term “Linker” describes the direct or indirect linkage of the antibody to the drug payload (D). Attachment of a linker to an antibody can be accomplished in a variety of ways, such as through surface lysines, reductive-coupling to oxidized carbohydrates, cysteine residues liberated by reducing interchain disulfide linkages, reactive cysteine residues engineered at specific sites, and acyl donor glutamine-containing tag or an endogenous glutamine made reactive by polypeptide engineering in the presence of transglutaminase and an amine. The present disclosure uses site specific methods to link the antibody to the drug payload. In one embodiment, conjugation occurs through cysteine residues that have been engineered into the antibody constant region. In another embodiment, conjugation occurs through acyl donor glutamine residues that have either been a) added to the antibody constant region via a peptide tag, b) engineered into the antibody constant region or c) made accessible / reactive by engineering surrounding residues. Linkers can be cleavable (i.e. , susceptible to cleavage under intracellular conditions) or non-cleavable. In some embodiments, the linker is a cleavable linker.

[0095]

[0053] As used herein, the term “drug” (D) refers to drug payload having a cytotoxic effect on tumors including the depletion, elimination and / or the killing of tumor cells. The terms drug, payload, and drug payload are used interchangeably. In some embodiments, the drug payload is a cytotoxic agent. Examples of drug payloads include but are not limited to monomethyl auristatin E (MMAE), monomethyl auristatin F (MMAF).

[0096]

[0054] As used herein, the term “linker-drug moiety” refers to the molecule resulting from a drug linked or conjugated to a linker.

[0097]

[0055] An “antibody” or “Ab” is an immunoglobulin molecule capable of recognizing and binding to a specific target or antigen, such as a carbohydrate, polynucleotide, lipid, polypeptide, etc., through at least one antigen recognition site, located in the variable region of the immunoglobulin molecule. As used herein, the term “antibody” encompasses any type of antibody, including but not limited to monoclonal antibodies, polyclonal antibodies, antigenbinding fragments (or portion), such as Fab, Fab’, F(ab’)2, Fd, Fv, Fc, etc., of intact antibodies that retain the ability to specifically bind to a given antigen (e.g. HER2), an isolated complementarity determining region (CDR), bispecific antibodies, heteroconjugate antibodies, mutants thereof, fusion proteins having an antibody, or antigen-binding fragment thereof, (e.g., a domain antibody), single chain (ScFv) and single domain antibodies (e.g., shark and camelid antibodies), maxibodies, minibodies, intrabodies, diabodies, triabodies, tetrabodies, v-NAR and bis-scFv (see, e.g., Holliger and Hudson, 2005, Nature Biotechnology 23(9): 1126-1136), humanized antibodies, chimeric antibodies and any other modified configuration of the immunoglobulin molecule that includes an antigen recognition site of the required specificity, including glycosylation variants of antibodies, amino acid sequence variants of antibodies, and covalently modified antibodies. The antibodies may be of murine, rat, human, or any other origin (including chimeric or humanized antibodies). In some aspects of the disclosure, the antibody, or antigen-binding fragment thereof, of the disclosed anti-HER2 antibody-drug conjugates is a chimeric, humanized, or a recombinant human antibody, or HER2-binding fragment thereof.

[0098]

[0056] 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. As known in the art, the variable regions of the heavy and light chain each consist of four framework regions (FR) connected by three complementarity determining regions (CDRs) also known as hypervariable regions. The CDRs in each chain are held together in close proximity by the FRs and, with the CDRs from the other chain, contribute to the formation of the antigen binding site of antibodies. There are at least two techniques for determining CDRs: (1) an approach based on cross-species sequence variability (i.e. , Kabat et al. Sequences of Proteins of Immunological Interest, (5th ed., 1991, National Institutes of Health, Bethesda MD)); and (2) an approach based on crystallographic studies of antigen-antibody complexes (Al-Lazikani et al., J. Molec. Biol. 273:927-948 (1997)). As used herein, a CDR may refer to CDRs defined by either approach or by a combination of both approaches.

[0099]

[0057] A CDR of a variable domain are comprised of amino acid residues within the variable region that are identified in accordance with the definitions of Kabat, Chothia, IMGT, the accumulation of both Kabat and Chothia, VBASE2, AbM, contact, and / or conformational definitions or any method of CDR determination well known in the art. Antibody CDRs may be identified as the hypervariable regions originally defined by Kabat et al. See, e.g., Kabat et al., 1992, Sequences of Proteins of Immunological Interest, 5th ed., Public Health Service, NIH, Washington D.C. The positions of the CDRs may also be identified as the structural loop structures originally described by Chothia and others. See, e.g., Chothia et al., Nature 342:877- 883, (1989). The CDR positions may also be derived from an analysis of the VBASE2 database. (See, e.g. Retter et al., Nucleic Acids Res. 33(Database Issue): D671-D674, 2005).

[0100]

[0058] Antibodies, antibody domains, and antigen-binding fragments thereof may be described as “polypeptides”, “oligopeptides”, “peptides” and “proteins”, i.e., chains of amino acids of any length, preferably, relatively short (e.g., 10-100 amino acids). The chain may be linear or branched, it may comprise modified amino acids, and / or may be interrupted by non-amino acids. The terms also encompass an amino acid chain that has been modified naturally or by intervention; for example, disulfide bond formation, glycosylation, lipidation, acetylation, phosphorylation, or any other manipulation or modification, such as conjugation with a labeling component. Also included within the definition are, for example, polypeptides containing one or more analogs of an amino acid (including, for example, unnatural amino acids, etc.), as well as other modifications known in the art. It is understood that the polypeptides can occur as single chains or associated chains. Amino acids may be referred to herein by either their commonly known three letter symbols or by the one-letter symbols recommended by the IUPAC-IUB Commission on Biochemical Nomenclature.

[0101]

[0059] As used herein, "humanized antibody" or “CDR grafted antibody” refers to forms of nonhuman (e.g. murine) antibodies that are chimeric immunoglobulins, immunoglobulin chains, or fragments thereof (such as Fv, Fab, Fab’, F(ab')2 or other antigen binding subsequences of antibodies) that contain minimal sequences derived from a non-human immunoglobulin. Preferably, humanized antibodies are human immunoglobulins (recipient antibody) in which residues from one or more complementarity determining regions (CDRs) of the recipient are replaced by residues from one or more CDRs of a non-human species (donor antibody) such as mouse, rat, or rabbit having the desired specificity, affinity, and capacity.

[0102]

[0060] As used herein, the term “angiogenesis” refers to blood vessel formation. Tumor angiogenesis is the growth of new blood vessels that tumors need to grow. This process is caused by the release of chemicals by the tumor and by host cells near the tumor.

[0103]

[0061] As used herein, the term “apoptosis” refers to the death of cells that occurs as a normal and controlled part of an organism's growth or development. Apoptosis is a type of cell death in which a series of molecular steps in a cell lead to its death. Apoptosis is one method the body uses to get rid of unneeded or abnormal cells. The process of apoptosis may be blocked in cancer cells.

[0104]

[0062] As used herein, the terms “cancer”, “cancerous”, or “malignant” refer to or describe the physiological condition in mammals that is typically characterized by unregulated cell growth. As used herein “cancer” refers to any malignant and / or invasive growth or tumor caused by abnormal cell growth. As used herein “cancer” refers to solid tumors named for the type of cells that form them, as well as cancer of blood, bone marrow, or the lymphatic system. Examples of solid tumors include but are not limited to sarcomas and carcinomas. Examples of cancers of the blood include but are not limited to leukemias, lymphomas and myeloma. The term “cancer” includes but is not limited to a primary cancer that originates at a specific site in the body, a metastatic cancer that has spread from the place in which it started to other parts of the body, a recurrence from the original primary cancer after remission, and a second primary cancer that is a new primary cancer in a person with a history of previous cancer of a different type from latter one.

[0105]

[0063] As used herein, the term “patient” or “subject” refers to any single subject for which therapy is desired or that is participating in a clinical trial, epidemiological study or used as a control, including humans and mammalian veterinary patients such as cattle, horses, dogs and cats. In some embodiments, the subject is a human.

[0106]

[0064] The terms “treat” or “treating” or “treatment” of a cancer as used herein means to administer a combination therapy according to the present disclosure to a subject having cancer, or diagnosed with cancer, to achieve at least one positive therapeutic effect, such as, for example, reduced number of cancer cells, reduced tumor size, reduced rate of cancer cell infiltration into peripheral organs, or reduced rate of tumor metastases or tumor growth, reversing, alleviating, inhibiting the progress of, or preventing the disorder or condition to which such term applies, or one or more symptoms of such disorder or condition. The term "treatment", as used herein, unless otherwise indicated, refers to the act of treating as "treating" is defined immediately above. The term “treating” also includes adjuvant and neo-adjuvant treatment of a subject.

[0107]

[0065] For the purposes of this disclosure, beneficial or desired clinical results include, but are not limited to, one or more of the following: reducing the proliferation of (or destroying) neoplastic or cancerous cell; inhibiting metastasis or neoplastic cells; shrinking or decreasing the size of a tumor; remission of the cancer; decreasing symptoms resulting from the cancer; increasing the quality of life of those suffering from the cancer; decreasing the dose of other medications required to treat the cancer; delaying the progression of the cancer; curing the cancer; overcoming one or more resistance mechanisms of the cancer; and / or prolonging survival of patients having the cancer. Positive therapeutic effects in cancer can be measured in a number of ways (see, for example, W. A. Weber, Assessing tumor response to therapy, J. Nucl. Med. 50 Suppl. 1:1S-10S (2009).

[0108]

[0066] In some embodiments, the treatment achieved by a combination therapy of the disclosure is any of the partial response (PR), complete response (CR), overall response (OR), objective response rate (ORR), progression free survival (PFS), radiographic PFS, metastasis fee survival (MFS), disease free survival (DFS) and overall survival (OS).

[0109]

[0067] As used herein, the term "sustained response" refers to the sustained effect on reducing tumor growth after cessation of a treatment. For example, the tumor size may be the same size or smaller as compared to the size at the beginning of the medicament administration phase. In some embodiments, the sustained response has a duration of at least the same as the treatment duration, at least 1.5x, 2x, 2.5x, or 3x length of the treatment duration, or longer.

[0110]

[0068] The anti-cancer effect of the method of treating cancer, including “objective response,” “complete response,” “partial response,” “progressive disease,” “stable disease,” “progression free survival,” “duration of response,” as used herein, may be defined and assessed by the investigators using RECIST v1.1 (Eisenhauer et al., New response evaluation criteria in solid tumours: Revised RECIST guideline (version 1.1), Eur J of Cancer, 2009; 45(2):228-47).

[0111]

[0069] In some embodiments of each of the methods, combinations and uses described herein, the therapeutic effect achieved by the compound of Formula (I), e.g., PF-07220060, in combination with a monoclonal antibody or an antibody-drug conjugate, and optionally in further combination with endocrine therapy agent is defined by reference to any of the following: complete response (CR), disease free survival (DFS), duration of response (DoR), overall response rate (ORR), overall survival (OS), partial response (PR), or progression free survival (PFS). In some embodiments, response to a combination therapy of the disclosure is any of PR, CR, PFS, DFS, OR OS that is assessed using Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 response criteria.

[0112]

[0070] In some embodiments of each of the methods, combinations and uses described herein, the disclosure relates to neoadjuvant therapy, adjuvant therapy, first-line therapy, second-line therapy, second-line or later lines of therapy, or third-line or later lines of therapy. In each case as further described herein, the cancer may be localized, advanced or metastatic, and the intervention may occur at point along the disease continuum (i.e. , at any stage of the cancer).

[0113]

[0071] In some embodiments of each of the methods, combinations and uses described herein, the treatment achieved by a combination therapy of the disclosure is measured by the time to PSA progression, the time to initiation of cytotoxic chemotherapy, or the proportion of patients with PSA response greater than or equal to 50%.

[0114]

[0072] The treatment regimen for a method, combination or use of the disclosure that is effective to treat cancer in a subject may vary according to factors such as the disease state, age, and weight of the subject, and the ability of the therapy to elicit an anti-cancer response in the subject. While an embodiment of any of the aspects of the disclosure may not be effective in achieving a positive therapeutic effect in every subject, it should do so in a statistically significant number of subjects as determined by any statistical test known in the art such as, but not limited to, the Cox log-rank test, the Cochran-Mantel-Haenszel log-rank test, the Student’s t- test, the chi2-test, the ll-test according to Mann and Whitney, the Kruskal-Wallis test (H-test), Jonckheere-Terpstrat-test and the Wilcon on-test.

[0115]

[0073] The terms “treatment regimen”, “dosing protocol” and “dosing regimen” may be used interchangeably to refer to the dose and timing of administration of each therapeutic agent in a combination therapy of the disclosure.

[0116]

[0074] As used herein, “ameliorate” or “ameliorating” refers to any reduction in the extent, severity, frequency, and / or likelihood of a symptom or clinical sign characteristic of a particular disease. “Ameliorating” also includes shortening or reduction in duration of a symptom. “Symptom” refers to any subjective evidence of disease or of a subject's condition.

[0117]

[0075] As used herein, an “amount” for use and for treating a subject refers to an amount that provides, in single or multiple doses, alone, or in combination with one or more other agents, a detectable response of any duration of time (transient, medium or long term), a desired outcome in or an objective or subjective benefit to a subject of any measurable or detectable degree or for any duration of time (e.g., for hours, days, months, years, in remission or cured). Such amounts typically are effective to ameliorate a disease, or one, multiple or all adverse effects I symptoms, consequences or complications of the disease, to a measurable extent, although reducing or inhibiting a progression or worsening of the disease, or providing stability (i.e., not worsening) state of the disease, is considered a satisfactory outcome. The term “therapeutically effective amount” also means an amount of an agent, alone, or in combination with one or more other agents, effective for producing a desired therapeutic effect upon administration to a subject, for example, to stem the growth, or result in the shrinkage, of a cancerous tumor. In reference to the treatment of cancer, a therapeutically effective amount refers to that amount which has the effect of (1) reducing the size of the tumor, (2) inhibiting (that is, slowing to some extent, preferably stopping) tumor metastasis emergence, (3) inhibiting to some extent (that is, slowing to some extent, preferably stopping) tumor growth or tumor invasiveness, and / or (4) relieving to some extent (or, preferably, eliminating) one or more signs or symptoms associated with the cancer. Therapeutic or pharmacological effectiveness of the doses and administration regimens may also be characterized as the ability to induce, enhance, maintain or prolong disease control and / or overall survival in patients with these specific tumors, which may be measured as prolongation of the time before disease progression.

[0118]

[0076] In reference to the treatment of cancer, beneficial or desired outcomes provided by the disclosure may include: (1) reducing the size of the tumor, (2) inhibiting (that is, slowing to some extent, preferably stopping) tumor metastasis, (3) inhibiting to some extent (that is, slowing to some extent, preferably stopping) tumor growth or tumor invasiveness, (4) reducing the incidence or ameliorating (that is, reducing to some extent, preferably, eliminating) one or more signs or symptoms associated with the cancer, (5) decreasing the dosage of another medication required to treat the cancer, (6) enhancing the efficacy or safety of another medication used to treat the cancer, and / or (7) delaying the time to progression of the cancer.

[0119]

[0077] An effective dosage can be administered in one or more administrations. Combination therapy involves administering each of the component drugs in the combination therapy in an amount sufficient to provide an observable improvement over the baseline clinically observable signs and symptoms of the disorder treated with the combination. The effective amount of a compound or pharmaceutical composition when used as part of a combination therapy may be less than the amount of the compound or pharmaceutical composition if used as a single agent to treat the same disorder.

[0120]

[0078] “Tumor” as it applies to a subject diagnosed with, or suspected of having, a cancer refers to a malignant or potentially malignant neoplasm or tissue mass of any size and includes primary tumors and secondary neoplasms. A solid tumor is an abnormal growth or mass of tissue that usually does not contain cysts or liquid areas. Examples of solid tumors are sarcomas, carcinomas, and lymphomas.

[0079] The term “tumor size” refers to the total size of the tumor which can be measured as the length and width of a tumor. Tumor size may be determined by a variety of methods known in the art, such as, e.g., by measuring the dimensions of tumor(s) upon removal from the subject, e.g., using callipers, or while in the body using imaging techniques, e.g., bone scan, ultrasound, CR or MRI scans.

[0121]

[0080] The term “additive” is used to mean that the result of the combination of two compounds, components or targeted agents is no greater than the sum of each compound, component or targeted agent individually.

[0122]

[0081] The term “synergy” or “synergistic” are used to mean that the result of the combination of two or more compounds, components or targeted agents is greater than the sum of each compound, component or targeted agent individually. This improvement in the disease, condition or disorder being treated is a “synergistic” effect and combinations providing a synergistic effect may be referred to as synergistic combinations. A “synergistic amount” is an amount of the combination of the two compounds, components or targeted agents that results in a synergistic effect, as “synergistic” is defined herein.

[0123]

[0082] Determining a synergistic interaction between one or two components, the optimum range for the effect and absolute dose ranges of each component for the effect may be definitively measured by administration of the components over different dose ranges, or dose ratios to patients in need of treatment. The observation of synergy in in vitro models or in vivo models can be predictive of the effect in humans and other species to measure a synergistic effect. The results of such studies can also be used to predict effective dose and plasma concentration ratio ranges and the absolute doses and plasma concentrations required in humans and other species such as by the application of pharmacokinetic or pharmacodynamics methods.

[0124]

[0083] A synergistic effect can be calculated, for example, using suitable methods such as the Sigmoid-Emax equation (Holford, N. H. G. and Scheiner, L. B., Clin. Pharmacokinet. 6: 429-453 (1981)), the equation of Loewe additivity (Loewe, S. and Muischnek, H., Arch. Exp. Pathol Pharmacol. 114: 313-326 (1926)) and the median-effect equation (Chou, T. C. and Talalay, P., Adv. Enzyme Regul. 22: 27-55 (1984)). Each equation referred to above can be applied to experimental data to generate a corresponding graph to aid in assessing the effects of the drug combination. The corresponding graphs associated with the equations referred to above are the concentration-effect curve, isobologram curve and combination index curve, respectively. Ma & Motsinger-Reif, Current Method for Quantifying Drug Synergism, Proteom. Bioinform (2019) 1(2):43-48; Tang et al., What is Synergy? The Saariselka Agreement Revisited, Front Pharmacol. (2015) Article 181, 6: 1-5.

[0084] As used herein, “endocrine therapy” or “hormone therapy” means an aromatase inhibitor, a selective estrogen receptor degrader (SERD), or a selective estrogen receptor modulator (SERM). In certain embodiments, endocrine therapy includes fulvestrant, tamoxifen, toremifene, anastrozole, exemestane, or letrozole.

[0125]

[0085] The term “antiestrogen” as used herein refers to a class of drugs that prevent estrogens like estradiol from mediating the biological effects in the body. Antiestrogens act by blocking the estrogen receptor (ER) and / or inhibiting or suppressing estrogen production. In an embodiment, an antiestrogen is an aromatase inhibitor, a selective estrogen receptor degrader (SERD) or a selective estrogen receptor modulator (SERM). Examples of an aromatase inhibitor include, but are not limited to, anastrozole. Examples of a SERD include, but are not limited to, fulvestrant. Additional SERDs include elacestrant (RAD-1901, Radius Health), SAR439859 (Sanofi), RG6171 (Roche), AZD9833 (AstraZeneca), AZD9496 (AstraZeneca), rintodestrant (G1 Therapeutics), ZN-c5 (Zentalis), LSZ102 (Novartis), D-0502 (Inventisbio), LY3484356 (Lilly), and SHR9549 (Jiansu Hengrui Medicine). Examples of a SERM include, but are not limited to, tamoxifen, clomifene and raloxifene. Additional SERMS include toremifene, lasofoxifene, bazedoxifene and afimoxifene.

[0126]

[0086] In an embodiment, the aromatase inhibitor includes letrozole, exemestane, and anastrozole. In an embodiment, the SERM includes tamoxifen, clomifene and raloxifene.

[0127]

[0087] In an embodiment, an antiestrogen of the present disclosure includes fulvestrant and letrozole. In an embodiment, an antiestrogen of the present disclosure includes fulvestrant. In an embodiment, an antiestrogen of the present disclosure includes letrozole.

[0128] CDK4 / 6 inhibitor

[0129]

[0088] Palbociclib, or 6-acetyl-8-cyclopentyl-5-methyl-2-(5-piperazin-1-yl-pyridin-2-ylamino)-8 / 7- pyrido[2,3-c(]pyrimidin-7-one (referred to herein as “palbo”) is a potent and selective inhibitor of CDK4 and CDK6, having the structure:

[0089] Palbociclib is described in WHO Drug Information, Vol. 27, No. 2, page 172 (2013).

[0130] Palbociclib and pharmaceutically acceptable salts thereof are disclosed in International

[0131] Publication No. WO 2003 / 062236 and U.S. Patent Nos. 6,936,612, 7,456,168 and RE47.739;

[0132] International Publication No. WO 2005 / 005426 and U.S. Patent Nos. 7,345,171 and 7,863,278;

[0133] International Publication No. WO 2008 / 032157 and U.S. Patent No. 7,781 ,583; and

[0134] International Publication No. WO 2014 / 128588. The contents of each of the foregoing references are incorporated herein by reference in their entirety.

[0135] CDK4 Inhibitors

[0136]

[0090] The disclosure relates to methods, combinations, and uses comprising a CDK4 inhibitor, wherein the CDK4 inhibitor is a compound of Formula (I), which includes hydrates (e.g., monohydrate), salts, and polymorphs thereof: wherein:

[0137] R1is H, F, or Cl;

[0138] R2is C1-C4 alkyl, where said C1-C4 alkyl is optionally substituted by R5;

[0139] R3is H or C1-C4 alkyl, where said C1-C4 alkyl is optionally substituted by R6;

[0140] R4is H or F; and each of R5and R6is independently OH, F, or C1-C2 alkoxy.

[0141]

[0091] In each instance recited herein, reference to “a compound of Formula (I)” may be replaced by “a CDK4 inhibitor of Formula (I).”

[0142]

[0092] In one embodiment, CDK4 selective inhibitors of the present disclosure include “PF- 07220060” which refers to 1,5-anhydro-3-({5-chloro-4-[4-fluoro-2-(2-hydroxypropan-2-yl)-1- (propan-2-yl)-1H-benzimidazol-6-yl]pyrimidin-2-yl}amino)-2,3-dideoxy-D-t / 7reo-pentitol or atirmociclib, which has the following chemical structure, including hydrates (e.g., monohydrate), salts and polymorphs thereof:

[0143]

[0144]

[0093] The preparation of compounds of Formula (I), including PF-07220060, are described in WO 2019 / 207463 and U.S. Patent No. 10,766,884, the contents of which are incorporated herein by reference in their entirety.

[0145]

[0094] PF-07220060 is disclosed in International Publication No. WO 2019 / 207463, U.S. Patent No. 10,766,884, and International Publication No. WO 2022 / 058871, the contents of which are incorporated herein by reference in their entirety. Unless indicated otherwise, all references herein to PF-07220060 include references to salts, solvates, hydrates, and complexes thereof, and to solvates, hydrates and complexes of salts thereof, including polymorphs, stereoisomers, and isotopically labelled versions thereof.

[0146]

[0095] PF-07220060 can be prepared as described in Example A94 of U.S. Publication No. 2019 / 0330196 and as described in WO 2022 / 058871 , the contents of which are incorporated herein by reference in their entirety. The anti-HER2 therapeutic agents of the disclosure include monoclonal antibodies and antibody-drug-conjugates which target the HER2 protein.

[0147] Monoclonal Antibodies

[0148]

[0096] The disclosure relates to methods, combinations, and uses comprising an anti-HER2 monoclonal antibody that targets the HER2 protein (also refers to as ‘HER2 antibody’). Examples of HER2 antibodies include, but are not limited to, trastuzumab (Herceptin®), trastuzumab-qyyp (Trazimera®), pertuzumab (Perjeta® disclosed in WO9123894), margetuximab (Margenza® as disclosed in WO01002244, zanidatamab as disclosed in WO1 8190924, zenocutuzumab as disclosed in WO18182422 and WO15130173), and combinations thereof, the contents of which are incorporated herein by reference in their entirety.

[0149] Antibody Drug Conjugates (ADCs)

[0150]

[0097] The disclosure relates to methods, combinations, and uses comprising an antibody drug conjugate (ADC).

[0098] ADCs include an antibody component conjugated to a drug payload (D) through the use of a linker (Linker). Generally, ADCs have a formula of Ab-(Linker-D)p, wherein (a) Ab is an antibody, or antigen-binding fragment thereof, that binds to HER2, (b) Linker-D is a linker-drug moiety, wherein Linker is a linker, and D is a drug and (c) p is the average number of linker / drug moieties that are attached to the antibody. In some embodiments, the Ab is Ab1 described herein. In some embodiments, the Ab is Ab2 described herein. In other words, p indicates the average number of units of the linker-drug conjugated per antibody molecule in the ADC.

[0151]

[0099] For site specific ADCs, p is a whole number due to the homogeneous nature of the ADC. In some embodiments, p is from about 1 to about 8. In one embodiment, p is 1. In one embodiment, p is 2. In one embodiment, p is 3. In one embodiment, p is 4. In other embodiments, p is greater than 4, such as 5, 6, 7, or 8. p can also be referred to as the drug-to- antibody ratio (DAR) or drug loading, which indicates the number of drug (D) molecules that are conjugated per antibody. The ADCs of the present disclosure use site specific conjugation such that there is essentially a homogeneous population of ADCs having one DAR in a composition of ADCs. In some embodiments, the DAR is 1. In some embodiments, the DAR is 2. In other embodiments, the DAR is 3. In other embodiments, the DAR is 4. In other embodiments, the DAR is greater than 4, such as 5, 6, 7, or 8.

[0152] I. HER2 antibodies in ADC:

[0153]

[0100] The antibody in the ADC used in the present disclosure specifically binds to HER2. In some embodiments, the antibody specifically binds to human HER2.

[0154]

[0101] The binding activity of the antibody against cancer cells can be confirmed using flow cytometry. The internalization of the antibody into cancer cells can be confirmed using (1) an assay of visualizing an antibody incorporated in cells under a fluorescence microscope using a secondary antibody (fluorescently labeled) binding to the therapeutic antibody (Cell Death and Differentiation (2008) 15, 751-761), (2) an assay of measuring a fluorescence intensity incorporated in cells using a secondary antibody (fluorescently labeled) binding to the therapeutic antibody (Molecular Biology of the Cell, Vol. 15, 5268-5282, December 2004), or (3) a Mab-ZAP assay using an immunotoxin binding to the therapeutic antibody wherein the toxin is released upon incorporation into cells to inhibit cell growth (Bio Techniques 28: 162-165, January 2000). As the immunotoxin, a recombinant complex protein of a diphtheria toxin catalytic domain and protein G may be used. i) Anti-HER2 antibody (Ab1)

[0155]

[0102] In some embodiments, the ADC is ADC1 which includes an antibody (e.g., Ab1) that comprises three complementarity-determining regions (CDRs) ( / .e., CDR-H1 , CDR-H2, and CDR-H3) from a heavy chain protein having the amino acid sequence shown in SEQ ID NO: 6 or 14 and three CDRs ( / .e., CDR-L1 , CDR-L2, and CDR-L3) from a light chain protein having the amino acid sequence shown in SEQ ID NO: 12, 16, 45, or 46.

[0156]

[0103] In some embodiments, the ADC1 includes an antibody (e.g., Ab1) that comprises a CDR-H1 having the amino acid sequence shown in SEQ ID NO: 2, a CDR-H2 having the amino acid sequence shown in SEQ ID NO: 3, and a CDR-H3 having the amino acid sequence shown in SEQ ID NO: 4, and / or a CDR-L1 having the amino acid sequence shown in SEQ ID NO: 8, a CDR-L2 having the amino acid sequence shown in SEQ ID NO: 9, and a CDR-L3 having the amino acid sequence shown in SEQ ID NO: 10.

[0157]

[0104] In some embodiments, the ADC1 includes an antibody (e.g., Ab1) that comprises the CDRs from a VH having the amino acid sequence shown in SEQ ID NO: 1 and the CDRs from a VL having the amino acid sequence shown in SEQ ID NO: 7 or 44.

[0158]

[0105] In some embodiments, the ADC1 includes an antibody (e.g., Ab1) that comprises the CDRs from a heavy chain protein comprising the amino acid sequence of SEQ ID NO: 6 or 14 and the CDRs from a light chain protein comprising the amino acid sequence of SEQ ID NO: 12, 16, 45, or 46.

[0159]

[0106] In some embodiments, the ADC1 includes an antibody (e.g., Ab1) comprising a heavy chain variable region that comprises an amino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO: 1, and comprising a light chain variable region that comprises an amino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO: 7 or 44. In some embodiments, the heavy chain variable region comprises an amino acid sequence that is at least 90% identical to SEQ ID NO: 1. In some embodiments, the heavy chain variable region comprises an amino acid sequence that is at least 91% identical to SEQ ID NO: 1. In some embodiments, the heavy chain variable region comprises an amino acid sequence that is at least 92% identical to SEQ ID NO: 1. In some embodiments, the heavy chain variable region comprises an amino acid sequence that is at least 93% identical to SEQ ID NO: 1. In some embodiments, the heavy chain variable region comprises an amino acid sequence that is at least 94% identical to SEQ ID NO: 1. In some embodiments, the heavy chain variable region comprises an amino acid sequence that is at least 95% identical to SEQ ID NO: 1. In some embodiments, the heavy chain variable region comprises an amino acid sequence that is at least 96% identical to SEQ ID NO: 1. In some embodiments, the heavy chain variable region comprises an amino acid sequence that is at least 97% identical to SEQ ID NO: 1. In some embodiments, the heavy chain variable region comprises an amino acid sequence that is at least 98% identical to SEQ ID NO: 1. In some embodiments, the heavy chain variable region comprises an amino acid sequence that is at least 99% identical to SEQ ID NO: 1. In some embodiments, the heavy chain variable region comprises the amino acid sequence of SEQ ID NO: 1. In some embodiments, the light chain variable region comprises an amino acid sequence that is at least 90% identical to SEQ ID NO: 7 or 44. In some embodiments, the light chain variable region comprises an amino acid sequence that is at least 91% identical to SEQ ID NO: 7 or 44. In some embodiments, the light chain variable region comprises an amino acid sequence that is at least 92% identical to SEQ ID NO: 7 or 44. In some embodiments, the light chain variable region comprises an amino acid sequence that is at least 93% identical to SEQ ID NO: 7 or 44. In some embodiments, the light chain variable region comprises an amino acid sequence that is at least 94% identical to SEQ ID NO: 7 or 44. In some embodiments, the light chain variable region comprises an amino acid sequence that is at least 95% identical to SEQ ID NO: 7 or 44. In some embodiments, the light chain variable region comprises an amino acid sequence that is at least 96% identical to SEQ ID NO: 7 or 44. In some embodiments, the light chain variable region comprises an amino acid sequence that is at least 97% identical to SEQ ID NO: 7 or 44. In some embodiments, the light chain variable region comprises an amino acid sequence that is at least 98% identical to SEQ ID NO: 7 or 44. In some embodiments, the light chain variable region comprises an amino acid sequence that is at least 99% identical to SEQ ID NO: 7 or 44. In some embodiments, the light chain variable region comprises the amino acid sequence of SEQ ID NO: 7 or 44. In some embodiments, the light chain variable region comprises the amino acid sequence of SEQ ID NO: 7. In some embodiments, the light chain variable region comprises the amino acid sequence of SEQ ID NO: 44. In some embodiments, the heavy chain variable region comprises the amino acid sequence of SEQ ID NO: 1 , and the light chain variable region comprises the amino acid sequence of SEQ ID NO: 7 or 44.

[0160]

[0107] In some embodiments, the ADC1 includes an antibody (e.g., Ab1) that comprises a heavy chain comprising a heavy chain variable region and a heavy chain constant region, and comprises a light chain comprising a light chain variable region and a light chain constant region. In some embodiments, the heavy chain comprises an amino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO: 6 or 14, and the light chain comprises an amino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO: 12, 16, 45, or 46. In some embodiments, the heavy chain comprises an amino acid sequence that is at least 90% identical to SEQ ID NO: 6 or 14. In some embodiments, the heavy chain comprises an amino acid sequence that is at least 91% identical to SEQ ID NO: 6 or 14. In some embodiments, the heavy chain comprises an amino acid sequence that is at least 92% identical to SEQ ID NO: 6 or 14. In some embodiments, the heavy chain comprises an amino acid sequence that is at least 93% identical to SEQ ID NO: 6 or 14. In some embodiments, the heavy chain comprises an amino acid sequence that is at least 94% identical to SEQ ID NO: 6 or 14. In some embodiments, the heavy chain comprises an amino acid sequence that is at least 95% identical to SEQ ID NO: 6 or 14. In some embodiments, the heavy chain comprises an amino acid sequence that is at least 96% identical to SEQ ID NO: 6 or 14. In some embodiments, the heavy chain comprises an amino acid sequence that is at least 97% identical to SEQ ID NO: 6 or 14. In some embodiments, the heavy chain comprises an amino acid sequence that is at least 98% identical to SEQ ID NO: 6 or 14. In some embodiments, the heavy chain comprises an amino acid sequence that is at least 99% identical to SEQ ID NO: 6 or 14. In some embodiments, the heavy chain comprises the amino acid sequence of SEQ ID NO: 6 or 14. In some embodiments, the heavy chain comprises the amino acid sequence of SEQ ID NO: 6. In some embodiments, the heavy chain comprises the amino acid sequence of SEQ ID NO: 14. In some embodiments, the light chain comprises an amino acid sequence that is at least 90% identical to SEQ ID NO: 12, 16, 45, or 46. In some embodiments, the light chain comprises an amino acid sequence that is at least 91% identical to SEQ ID NO: 12, 16, 45, or 46. In some embodiments, the light chain comprises an amino acid sequence that is at least 92% identical to SEQ ID NO: 12, 16, 45, or 46. In some embodiments, the light chain comprises an amino acid sequence that is at least 93% identical to SEQ ID NO: 12, 16, 45, or 46. In some embodiments, the light chain comprises an amino acid sequence that is at least 94% identical to SEQ ID NO: 12, 16, 45, or 46. In some embodiments, the light chain comprises an amino acid sequence that is at least 95% identical to SEQ ID NO: 12, 16, 45, or 46. In some embodiments, the light chain comprises an amino acid sequence that is at least 96% identical to SEQ ID NO: 12, 16, 45, or 46. In some embodiments, the light chain comprises an amino acid sequence that is at least 97% identical to SEQ ID NO: 12, 16, 45, or 46. In some embodiments, the light chain comprises an amino acid sequence that is at least 98% identical to SEQ ID NO: 12, 16, 45, or 46. In some embodiments, the light chain comprises an amino acid sequence that is at least 99% identical to SEQ ID NO: 12, 16, 45, or 46. In some embodiments, the light chain comprises the amino acid sequence of SEQ ID NO: 12, 16, 45, or 46. In some embodiments, the light chain comprises the amino acid sequence of SEQ ID NO: 12. In some embodiments, the light chain comprises the amino acid sequence of SEQ ID NO: 16. In some embodiments, the light chain comprises the amino acid sequence of SEQ ID NO: 45. In some embodiments, the light chain comprises the amino acid sequence of SEQ ID NO: 46. In some embodiments, the heavy chain comprises the amino acid sequence of SEQ ID NO: 6 or 14, and the light chain comprises the amino acid sequence of SEQ ID NO: 12, 16, 45, or 46.

[0108] In some embodiments, the ADC1 includes an antibody (e.g., Ab1) designated T(kK183C+K290C), which is described in US 2017 / 0151341 and WO 2017 / 093844, each of which is herein incorporated by reference in its entirety. The antibody T(kK183C+K290C) comprises a heavy chain comprising the amino acid sequence of SEQ ID NO: 14 and a light chain comprising the amino acid sequence of SEQ ID NO:16 or 46. In particular embodiments, the ADC includes an antibody that comprises a heavy chain protein having the amino acid sequence shown in SEQ ID NO: 14 and a light chain protein having the amino acid sequence shown in SEQ ID NO: 16 or 46.

[0161]

[0109] In some embodiments, the antibodies are conjugated to the Linker-D complexes via cysteine residues. In some embodiment, the site-specific conjugation occurs through one or more cysteine residues that have been engineered into an antibody constant region. Methods of preparing HER2 antibodies for site specific conjugation through cysteine residues can be performed as described in PCT Publication No. WQ2013 / 093809, which is incorporated by reference in its entirety.

[0162]

[0110] In a more specific embodiment, positions 290 on the heavy chain constant region and position 183 on the light chain constant region are altered to cysteine for conjugation.

[0163]

[0111] In some embodiments, the antibodies bind to the same epitope on HER2 as trastuzumab (Herceptin®). In a specific embodiment, the antibodies have the same variable region CDRs as trastuzumab (Herceptin®). In a more specific embodiment, the antibodies have the same variable regions (i.e. , VH and VL) as trastuzumab (Herceptin®). Trastuzumab (Herceptin®) is a recombinant humanized monoclonal antibody, selectively targeting on the extracellular domain of human epidermal growth factor receptor-2 (HER2).

[0164]

[0112] Trastuzumab-qyyp (Trazimera®) is a biosimilar to trastuzumab (Herceptin®).

[0165]

[0113] Tables 1 and 2 provide the amino acid (protein) sequences and associated nucleic acid (DNA) sequences of certain humanized HER2 antibodies that may be used in constructing the site-specific ADCs described herein. The CDRs shown are defined by Kabat numbering scheme.

[0166]

[0114] The antibody heavy chains and light chains shown in Table 1 contain the trastuzumab heavy chain variable region (VH) and light chain variable region (VL). The heavy chain constant region and light chain constant region shown in Table 1 are derivatized from trastuzumab and contain one or more modifications (relative to the respective sequences of trastuzumab) to allow for site specific conjugation when making the ADCs used in the disclosure. Modifications to the amino acid sequences in the antibody constant region to allow for site specific conjugation are underlined and bolded. The nomenclature for the antibodies derivatized from trastuzumab is T (for trastuzumab) and then in parenthesis the position of the amino acid of modification flanked by the single letter amino acid code for the wild type residue and the single letter amino acid code for the residue that is now in that position in the derivatized antibody. An exception to this nomenclature is “kK183C” which denotes that position 183 on the light (kappa) chain has been modified from a lysine to a cysteine. The positions of the amino acids of modifications, such as “K290C” and “kK183C,” are numbered according to the numbering of Ell index of Kabat.

[0167]

[0115] Table 1 : Sequences of Humanized HER2 Antibodies - Trastuzumab ii) Anti-HER2 antibody (Ab2)

[0168]

[0116] In some embodiments, the ADC is ADC2 which comprises Ab2 which is conjugated with a drug payload (D2) via a linker (Linker2), and Ab2 is an antibody that binds to HER2 and comprises:

[0169] (1) a heavy chain variable region comprising a CDR-H1, CDR-H2, and CDR-H3, in which the CDR-H1 comprises the amino acid sequence of SEQ ID NO: 31, the CDR-H2 comprises the amino acid sequence of SEQ ID NO: 33, and the CDR-H3 comprises the amino acid sequence of SEQ ID NO: 34 or 35; and

[0170] (2) a light chain variable region comprising a CDR-L1, CDR-L2, and CDR-L3, in which the CDR-L1 , CDR-L2, and CDR-L3 comprise the amino acid sequences of SEQ ID NOs: 36, 37, and 38, respectively; wherein D2 is selected from MMAE and MMAF; and wherein Linker2 is linked with Ab2, optionally through thiol, and is selected from mc-vc-pAB and me.

[0171]

[0117] In some embodiments, the ADC2 comprises Ab2 (e.g., RC48) which is an antibody that binds to HER2 and comprises:

[0172] (1) a heavy chain variable region comprising a CDR-H1, CDR-H2, and CDR-H3, in which the CDR-H1 comprises the amino acid sequence of SEQ ID NO: 31, the CDR-H2 comprises the amino acid sequence of SEQ ID NO: 33, and the CDR-H3 comprises the amino acid sequence of SEQ ID NO: 34 or 35; and

[0173] (2) a light chain variable region comprising a CDR-L1 , CDR-L2, and CDR-L3, in which the CDR-L1 , CDR-L2, and CDR-L3 comprise the amino acid sequence of SEQ ID NOs: 36, 37, and 38, respectively;

[0118] In some embodiments, the ADC2 comprises Ab2 comprising a heavy chain variable region that comprises an amino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO: 39, and comprising a light chain variable region that comprises an amino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO: 40. In some embodiments, the heavy chain variable region comprises an amino acid sequence that is at least 90% identical to SEQ ID NO: 39. In some embodiments, the heavy chain variable region comprises an amino acid sequence that is at least 91% identical to SEQ ID NO: 39. In some embodiments, the heavy chain variable region comprises an amino acid sequence that is at least 92% identical to SEQ ID NO: 39. In some embodiments, the heavy chain variable region comprises an amino acid sequence that is at least 93% identical to SEQ ID NO: 39. In some embodiments, the heavy chain variable region comprises an amino acid sequence that is at least 94% identical to SEQ ID NO: 39. In some embodiments, the heavy chain variable region comprises an amino acid sequence that is at least 95% identical to SEQ ID NO: 39. In some embodiments, the heavy chain variable region comprises an amino acid sequence that is at least 96% identical to SEQ ID NO: 39. In some embodiments, the heavy chain variable region comprises an amino acid sequence that is at least 97% identical to SEQ ID NO: 39. In some embodiments, the heavy chain variable region comprises an amino acid sequence that is at least 98% identical to SEQ ID NO: 39. In some embodiments, the heavy chain variable region comprises an amino acid sequence that is at least 99% identical to SEQ ID NO: 39. In some embodiments, the heavy chain variable region comprises the amino acid sequence of SEQ ID NO: 39. In some embodiments, the light chain variable region comprises an amino acid sequence that is at least 90% identical to SEQ ID NO: 40. In some embodiments, the light chain variable region comprises an amino acid sequence that is at least 91% identical to SEQ ID NO: 40. In some embodiments, the light chain variable region comprises an amino acid sequence that is at least 92% identical to SEQ ID NO: 40. In some embodiments, the light chain variable region comprises an amino acid sequence that is at least 93% identical to SEQ ID NO: 40. In some embodiments, the light chain variable region comprises an amino acid sequence that is at least 94% identical to SEQ ID NO: 40. In some embodiments, the light chain variable region comprises an amino acid sequence that is at least 95% identical to SEQ ID NO: 40. In some embodiments, the light chain variable region comprises an amino acid sequence that is at least 96% identical to SEQ ID NO: 40. In some embodiments, the light chain variable region comprises an amino acid sequence that is at least 97% identical to SEQ ID NO: 40. In some embodiments, the light chain variable region comprises an amino acid sequence that is at least 98% identical to SEQ ID NO: 40. In some embodiments, the light chain variable region comprises an amino acid sequence that is at least 99% identical to SEQ ID NO: 40. In some embodiments, the light chain variable region comprises the amino acid sequence of SEQ ID NO: 40. In some embodiments, the heavy chain variable region comprises the amino acid sequence of SEQ ID NO: 39, and the light chain variable region comprises the amino acid sequence of SEQ ID NO: 40.

[0174]

[0119] In some embodiments, the ADC2 comprises Ab2 that comprises a heavy chain comprising a heavy chain variable region and a heavy chain constant region, and comprises a light chain comprising a light chain variable region and a light chain constant region. In some embodiments, the heavy chain comprises an amino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO: 41 or 42, and the light chain comprises an amino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO: 43. In some embodiments, the heavy chain comprises an amino acid sequence that is at least 90% identical to SEQ ID NO: 41 or 42. In some embodiments, the heavy chain comprises an amino acid sequence that is at least 91% identical to SEQ ID NO: 41 or 42. In some embodiments, the heavy chain comprises an amino acid sequence that is at least 92% identical to SEQ ID NO: 41 or 42. In some embodiments, the heavy chain comprises an amino acid sequence that is at least 93% identical to SEQ ID NO: 41 or 42. In some embodiments, the heavy chain comprises an amino acid sequence that is at least 94% identical to SEQ ID NO: 41 or 42. In some embodiments, the heavy chain comprises an amino acid sequence that is at least 95% identical to SEQ ID NO: 41 or 42. In some embodiments, the heavy chain comprises an amino acid sequence that is at least 96% identical to SEQ ID NO: 41 or 42. In some embodiments, the heavy chain comprises an amino acid sequence that is at least 97% identical to SEQ ID NO: 41 or 42. In some embodiments, the heavy chain comprises an amino acid sequence that is at least 98% identical to SEQ ID NO: 41 or 42. In some embodiments, the heavy chain comprises an amino acid sequence that is at least 99% identical to SEQ ID NO: 41 or 42. In some embodiments, the heavy chain comprises the amino acid sequence of SEQ ID NO: 41 or 42. In some embodiments, the heavy chain comprises the amino acid sequence of SEQ ID NO: 41. In some embodiments, the heavy chain comprises the amino acid sequence of SEQ ID NO: 42s. In some embodiments, the light chain comprises an amino acid sequence that is at least 90% identical to SEQ ID NO: 43. In some embodiments, the light chain comprises an amino acid sequence that is at least 91% identical to SEQ ID NO: 43. In some embodiments, the light chain comprises an amino acid sequence that is at least 92% identical to SEQ ID NO: 43. In some embodiments, the light chain comprises an amino acid sequence that is at least 93% identical to SEQ ID NO: 43. In some embodiments, the light chain comprises an amino acid sequence that is at least 94% identical to SEQ ID NO: 43. In some embodiments, the light chain comprises an amino acid sequence that is at least 95% identical to SEQ ID NO: 43. In some embodiments, the light chain comprises an amino acid sequence that is at least 96% identical to SEQ ID NO: 43. In some embodiments, the light chain comprises an amino acid sequence that is at least 97% identical to SEQ ID NO: 43. In some embodiments, the light chain comprises an amino acid sequence that is at least 98% identical to SEQ ID NO: 43. In some embodiments, the light chain comprises an amino acid sequence that is at least 99% identical to SEQ ID NO: 43. In some embodiments, the light chain comprises the amino acid sequence of SEQ ID NO: 43. In some embodiments, the heavy chain comprises the amino acid sequence of SEQ ID NO: 41 or 42, and the light chain comprises the amino acid sequence of SEQ ID NO: 43.

[0175]

[0120] In some embodiments, Ab2 is humanized antibody RC48 (also known as disitamab) described in U.S. Patent No. 10,087,260, the content of which is herein incorporated by reference in its entirety. RC48 is a recombinant human HER2 antibody, which is able to bind to the extracellular domain of HER2 with high affinity.

[0176]

[0121] In some embodiments, the ADC2 is disitamab vedotin, as described in U.S. Patent No. 10,087,260.

[0177]

[0122] The antibody heavy chains and light chains shown in Table 2 contain the disitamab heavy chain variable region (VH) and disitamab light chain variable region (VL).

[0178]

[0123] Table 2: Sequences of Humanized HER2 Antibodies - Disitamab

[0179]

[0124] The disclosure and the methods of making Ab2 is described in U.S. Patent No. 10,087,260, the content of which is herein incorporated by reference in its entirety.

[0180]

[0125] Additional HER2 ADCs of the disclosure include but are not limited to ado-trastuzumab emtasine (Kadcyla®, as disclosed in WO15115091) and Fam-trastuzumab-deruxtecan (Enhertu®, as disclosed in WO0100245).

[0181] II. Drug Payloads

[0182]

[0126] In one embodiment, the drug component of the ADCs of the disclosure is an anti-mitotic drug, which is an auristatin drug, such as 2-methylalanyl-N-[(3R,4S,5S)-3-methoxy-1-{(2S)-2- [(1 R,2R)-1-methoxy-2-methyl-3-oxo-3-{[(1S)-2-phenyl-1-(1 ,3-thiazol-2- yl)ethyl]amino}propyl]pyrrolidin-1-yl}-5-methyl-1 -oxoheptan-4-yl]-N-methyl-L-valinamide (also known as “0101”), having the following structure:

[0183]

[0127] Auristatins inhibit cell proliferation by inhibiting the formation of microtubules during mitosis through inhibition of tubulin polymerization. PCT International Publication No. WO 2013 / 072813, which is incorporated by reference in its entirety, discloses auristatins that are useful in the manufacture of the ADCs of the disclosure and provides methods of producing those auristatins.

[0184]

[0128] In another embodiment, the drug component of the ADCs of the disclosure is monomethyl auristatin E (‘MMAE’).

[0185]

[0129] In another embodiment, the drug component of the ADCs of the disclosure is monomethyl auristatin F (‘MMAF’).

[0186]

[0130] The drug-to-antibody ratio (DAR) or drug loading indicates the number of drug (D) molecules that are conjugated per antibody. The ADCs of the present disclosure use site specific conjugation such that there is essentially a homogeneous population of ADCs having one DAR in a composition of ADCs. In some embodiments, the DAR is 1. In some embodiments, the DAR is 2. In other embodiments, the DAR is 3. In other embodiments, the DAR is 4. In other embodiments, the DAR is greater than 4.

[0187]

[0131] Using conventional conjugation (rather than site specific conjugation) results in a heterogeneous population of different species of ADCs, each of which has a different individual DAR. Compositions of ADCs prepared in this way include a plurality of antibodies, each antibody conjugated to a particular number of drug molecules. As such, the compositions have an average DAR.

[0188] III. Linkers

[0189]

[0132] A linker is a bifunctional compound which can be used to link a drug and an antibody to form an antibody-drug conjugate (ADC). Such conjugates allow the selective delivery of drugs to tumor cells. Suitable linkers include, for example, cleavable and non-cleavable linkers. A cleavable linker is typically susceptible to cleavage under intracellular conditions. Major mechanisms by which a conjugated drug is cleaved from an antibody include hydrolysis in the acidic pH of the lysosomes (hydrazones, acetals, and cis-aconitate-like amides), peptide cleavage by lysosomal enzymes (the cathepsins and other lysosomal enzymes), and reduction of disulfides. As a result of these varying mechanisms for cleavage, mechanisms of linking the drug to the antibody also vary widely and any suitable linker can be used.

[0190]

[0133] In specific embodiments, the linker is a cleavable linker such that the payload can induce a bystander effect once the linker is cleaved. The bystander effect is when a membrane permeable drug is released from the antibody (i.e. , by cleaving of a cleavable linker) and crosses the cellular membrane and, upon diffusion, induces killing of cells surrounding the cell that initially internalized the ADC.

[0191]

[0134] Suitable cleavable linkers include, but are not limited to, a peptide linker cleavable by an intracellular protease, such as lysosomal protease or an endosomal protease, such as maleimidocaproyl-valine-citrulline-p-aminobenzyloxycarbonyl (also known as “mc-vc-pAB” or simply “vc”), which is used in the ADCs shown in Figs. 2 and 3 and which has the following structure:

[0192]

[0135] Linkers are attached to the monoclonal antibody via the left side of the molecule and the drug via the right side of the molecule (see example of linker mc-vc-pAB as depicted above).

[0193]

[0136] In some embodiments, the linker is a cleavable linker is maleimidocaproyl valine citrulline-p-amino-benzyloxycarbonyl (‘mc-vc-pAB’).

[0194]

[0137] In some embodiments, the linker is an uncleavable, such as maleimidocaproyl (‘me’).

[0195]

[0138] More specific embodiments of ADCs are described below:

[0196]

[0139] In some embodiments, the ADC is ADC1 which is a site specific HER2 antibody drug conjugate as described in U.S. Patent Publication No. 2017 / 0151341 and International Publication No. WO2017 / 093844, the content of each of which is herein incorporated by reference in its entirety. These ADCs conjugate the drug payload to the antibody at particular engineered residues on the antibody heavy and / or light chain.

[0197]

[0140] In specific embodiments, the ADC is ADC1 having the following formula:

[0198]

[0141] wherein Ab1 is an HER2 antibody, or antigen-binding fragment thereof, that binds to HER2. In specific embodiments, Ab1 comprises (1) a heavy chain comprising SEQ ID NO: 6 or 14; and (2) a light chain comprising SEQ ID NO: 12, 16, 45, or 46. The partial structure consisting of a linker and a drug in ADC1 is referred to as “linker-drug” or “L-D.” In specific embodiments, the L-D is conjugated to the antibody via a thioether bond (i.e. , via the S atom of a cysteine residue).

[0199]

[0142] In one embodiment, the ADC1 is T(kK183C+K290C)-vc-0101 ADC, as shown in FIG. 1.

[0200]

[0143] In some embodiments, the ADC is ADC2 which comprises Ab2 that is conjugated with a therapeutic agent (D2) via a linker (L2), wherein Ab2 is an antibody that binds to HER2 and comprises:

[0201] (1) a heavy chain variable region comprising a CDR-H1, CDR-H2, and CDR-H3, in which the CDR-H1 comprises the amino acid sequence of SEQ ID NO: 31, the CDR- H2 comprises the amino acid sequence of SEQ ID NO: 33, and the CDR-H3 comprises the amino acid sequence of SEQ ID NO: 34 or 35; and

[0202] (2) a light chain variable region comprising a CDR-L1, CDR-L2, and CDR-L3, in which the CDR-L1 , CDR-L2, and CDR-L3 comprise the amino acid sequences of SEQ ID NOs: 36, 37, and 38, respectively.

[0203]

[0144] In some embodiments, the ADC is ADC2 which comprises Ab2 that is conjugated with a therapeutic agent (D2) via a linker (L2), wherein Ab2 is an antibody that binds to HER2 and comprises:

[0204] (1) a heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 39; and

[0205] (2) a light chain variable region comprising the amino acid sequence of SEQ ID NO: 40.

[0206]

[0145] In some embodiments, the ADC is ADC2 which comprises Ab2 that is conjugated with a therapeutic agent (D2) via a linker (L2), wherein Ab2 is an antibody that binds to HER2 and comprises:

[0207] (1) a heavy chain comprising the amino acid sequence of SEQ ID NO: 41 or 42; and

[0208] (2) a light chain comprising the amino acid sequence of SEQ ID NO: 43.

[0146] In one embodiment, the ADC2 is RC48-vc-MMAE, as shown in FIG. 2. In one embodiment, the ADC2 is RC48-vc-MMAF, as shown in FIG. 3. In one embodiment, the ADC2 is RC48-mc-MMAF, as shown in FIG. 4.

[0209]

[0147] The ADC2 disclosed herein is HER2 antibody drug conjugate as described in U.S. Patent No. 10,087,260, the content of each of which is herein incorporated by reference in its entirety.

[0210] Pharmaceutically acceptable salts

[0211]

[0148] As used herein, the term “pharmaceutically acceptable salt” refers to those salts which retain the biological effectiveness and properties of the parent compound. The phrase “pharmaceutically acceptable salt(s)”, as used herein, unless otherwise indicated, includes salts of acidic or basic groups which may be present in the compounds of the formulae disclosed herein. For example, the compounds of the disclosure that are basic in nature may be capable of forming a wide variety of salts with various inorganic and organic acids. The acids that may be used to prepare pharmaceutically acceptable acid addition salts of such basic compounds of those that form non-toxic acid addition salts, i.e. , salts containing pharmacologically acceptable anions. Examples of anions suitable for mono- and di- acid addition salts include, but are not limited to, acetate, asparatate, benzenesulfonate, benzoate, besylate, bicarbonate, bisulfate, bitartrate, bromide, calcium edetate, camsylate, carbonate, chloride, citrate, decanoate, edetate, edislyate, estolate, esylate, fumarate, gluceptate, gluconate, glutamate, glycollate, hexanoate, hexylresorcinate, hydrabamine, hydroxynaphthoate, iodide, isethionate, lactate, lactobionate, malate, maleate, mandelate, mesylate, methylsulfate, mucate, napsylate, nitrate, octanoate, oleate, pamoate (embonate), pantothenate, phosphate, polygalacturonate, propionate, salicylate, stearate, subacetate, succinate, sulfate, tannate, tartrate, teoclate, tosylate, triethiodode, and valerate salts. Alternatively, compounds that are acidic in nature may be capable of forming base salts with various pharmacologically acceptable cations which form non-toxic base salts. Such non-toxic base salts include, but are not limited to, those derived from such pharmacologically acceptable cations such as alkali metal cations (e.g., potassium and sodium) and alkaline earth metal cations (e.g., calcium and magnesium), ammonium or water-soluble amine addition salts such as N-methylglucamine-(meglumine), and the lower alkanolammonium and other base salts of pharmaceutically acceptable organic amines. Examples of cations suitable for such salts include alkali metal or alkaline-earth metal salts and other cations, including aluminium, arginine, benzathine, calcium, chloroprocaine, choline, diethanolamine, ethanolamine, ethylenediamine, lysine, magnesium, histidine, lithium, meglumine, potassium, procaine, sodium, triethyamine and zinc. Salts may be prepared by conventional techniques. Hemisalts of acids and bases may also be formed, for example, hemisulphate and hemicalcium salts. For a review on suitable salts, see Handbook of Pharmaceutical Salts: Properties, Selection, and Use by Stahl and Wermuth (Wiley-VCH, 2002). Methods for making pharmaceutically acceptable salts are known to those of skill in the art.

[0212]

[0149] Unless indicated otherwise, all references herein to CDK4 inhibitors, to compounds of Formula (I), and include references to pharmaceutically acceptable salts, solvates, hydrates and complexes thereof, and include amorphous and polymorphic forms, stereoisomers, and isotopically labeled versions thereof.

[0213] Therapeutic Methods, Combinations, Uses

[0214]

[0150] The present disclosure provides methods, combinations and uses for treating cancer. Some embodiments provided herein result in one or more of the following effects: (1) inhibiting cancer cell proliferation; (2) inhibiting cancer cell invasiveness; (3) inducing apoptosis of cancer cells; (4) inhibiting cancer cell metastasis; (5) inhibiting angiogenesis; or (6) overcoming one or more resistance mechanisms relating to a cancer treatment.

[0215]

[0151] In some embodiments of the methods, combinations and uses described herein, the cancer is selected from the group consisting of prostate cancer, breast cancer, lung cancer (including non-small cell lung cancer, NSCLC, and small cell lung cancer, SCLC), liver cancer (including hepatocellular carcinoma, HCC), kidney cancer (including renal cell carcinoma, RCC), bladder cancer (including urothelial carcinomas, such as upper urinary tract urothelial carcinoma, UUTUC), ovarian cancer (including epithelial ovarian cancer, EOC), peritoneal cancer (including primary peritoneal cancer, PPC), fallopian tube cancer, cervical cancer, uterine cancer (including endometrial cancer), pancreatic cancer, stomach cancer, colorectal cancer, esophageal cancer, head and neck cancer (including squamous cell carcinoma of the head and neck (SCCHN), thyroid cancer, and salivary gland cancer), testicular cancer, adrenal cancer, skin cancer (including basal cell carcinoma and melanoma), brain cancer (including astrocytoma, meningioma, and glioblastoma), sarcoma (including osteosarcoma and liposarcoma), and lymphoma (including mantle cell lymphoma, MCL).

[0216]

[0152] In some embodiments of each of the methods, combinations and uses described herein, the cancer is androgen-dependent.

[0217]

[0153] In some embodiments of each of the methods, combinations and uses described herein, the cancer expresses androgen receptors, which may sometimes be referred to as androgen receptor (AR)-positive or AR+ cancer.

[0218]

[0154] In some embodiments of the methods, combinations and uses described herein, the cancer is advanced or metastatic cancer. In some embodiments of the methods, combinations and uses described herein, the cancer is early stage or non-metastatic cancer.

[0155] In some embodiments of the methods, combinations and uses described herein, the cancer is characterized by deleterious germline mutations in breast cancer susceptibility gene 1 (BRCA1) or breast cancer susceptibility gene 2 (BRCA2) (i.e. , is germline BRCA1- or BRCA2- mutated). In some such embodiments, the BRCA1- or BRCA2-mutated cancer is prostate cancer, breast cancer, ovarian cancer, peritoneal cancer, fallopian tube cancer, or pancreatic cancer.

[0219]

[0156] In some embodiments of the methods, combinations and uses described herein, the cancer is characterized by amplification or overexpression of CDK4, CDK6 or cyclin D1 (CCND1). In some embodiments, the cancer is retinoblastoma protein (RB)-positive or RB- proficient.

[0220]

[0157] In some embodiments of each of the methods, combinations, uses described herein, the cancer is resistant to a therapeutic agent or class of agents, such as a standard of care agent or class for the particular cancer. In some embodiments of each of the methods, combinations, uses described herein, the cancer is characterized by innate or acquired resistance to a therapeutic agent or class of agents. In some such embodiments, the cancer is resistant to treatment with antiandrogens, taxanes, platinum agents, aromatase inhibitors, selective estrogen receptor degraders (SERDs), selective estrogen receptor modulators (SERMs), or CDK4 / 6 inhibitors.

[0221]

[0158] In some embodiments of each of the methods, combinations and uses described herein, the cancer is resistant to treatment with a taxane (i.e., the cancer is a taxane resistant cancer). In some embodiments of each of the methods, combinations and uses described herein, the cancer is resistant to treatment with a platinum agent (i.e., the cancer is a platinum resistant cancer).

[0222]

[0159] In some embodiments of each of the methods, combinations and uses described herein, the cancer is resistant to treatment with an aromatase inhibitor, a SERD, or a SERM.

[0223]

[0160] In some embodiments of each of the methods, combinations and uses described herein, the cancer is resistant to treatment with a CDK4 inhibitor or a CDK4 / 6 inhibitor. In some such embodiments, the cancer is resistant to treatment with a CDK4 / 6 inhibitor selected from the group consisting of palbociclib, ribociclib or abemaciclib, or a pharmaceutically acceptable salt thereof. In some such embodiments the cancer is resistant to treatment with palbociclib, or a pharmaceutically acceptable salt thereof.

[0224]

[0161] In some embodiments of each of the methods, combinations, and uses described herein, the cancer is refractory, i.e., the cancer does not respond at all to treatment with a therapeutic agent or class (including a standard of care agent or class for the particular cancer) or initially responds but starts to grow again in a very short period of time.

[0162] In some embodiments of each of the methods, combinations and uses described herein, the cancer is breast cancer. In some such embodiments, the breast cancer is androgendependent breast cancer. In some embodiments, the breast cancer is AR+ breast cancer.

[0225]

[0163] In some embodiments of the methods, combinations and uses described herein, the breast cancer is advanced or metastatic breast cancer. In some embodiments of the methods, combinations and uses described herein, the breast cancer is early stage or non-metastatic breast cancer.

[0226]

[0164] In some embodiments of the methods, combinations and uses described herein, the breast cancer is characterized by amplification or overexpression of CDK4, CDK6 or cyclin D1 (CCND1). In some embodiments, the breast cancer is characterized as RB-positive, RB- proficient, or RB wild type.

[0227]

[0165] In some embodiments of the methods, combinations and uses described herein, the breast cancer is BRCA1- or BRCA2-mutated breast cancer.

[0228]

[0166] In some embodiments of the methods, combinations and uses described herein, the breast cancer is P I K3CA- mutated cancer breast cancer.

[0229]

[0167] In some embodiments of the methods, combinations and uses described herein, the breast cancer is refractory or resistant to treatment with, or has progressed on, one or more standard of care agents. In some such embodiments, the breast cancer is refractory or resistant to treatment with, or has progressed on, an antiestrogen, such as an aromatase inhibitor, SERD, or a SERM. In some such embodiments, the breast cancer is refractory or resistant to treatment with, or has progressed on, a CDK4 / 6 inhibitor, such as palbociclib or a pharmaceutically acceptable salt thereof. In other embodiments, the breast cancer is refractory or resistant to treatment with, or has progressed on, treatment with antineoplastic chemotherapeutic agents such as taxanes, platinum agents, anthracyclines or anti-metabolites.

[0230]

[0168] In some embodiments of each of the methods, combinations and uses described herein, the breast cancer is hormone receptor (HR)-positive (HR+) breast cancer, i.e. , the breast cancer is estrogen receptor (ER)-positive (ER+) and / or progesterone receptor (PR)-positive (PR+).

[0231]

[0169] In some embodiments, the breast cancer is hormone receptor (HR)-negative (HR-), i.e., the breast cancer is estrogen receptor (ER)-negative (ER-) and progesterone receptor (PR)- negative (PR-).

[0232]

[0170] In some embodiments, the breast cancer is human epidermal growth factor receptor 2 (HER2)-positive (HER2+).

[0233]

[0171] In some embodiments, the breast cancer is human epidermal growth factor receptor 2 (HER2)-negative (HER2-). In some such embodiments, the breast cancer is is estrogen receptor alpha (ERa)-negative.

[0172] In some embodiments, the breast cancer is triple negative breast cancer (TNBC), i.e., the breast cancer is ER-, PR- and HER2-.

[0234]

[0173] In some embodiments, the breast cancer is selected from the group consisting of HR+ / HER2- breast cancer, HR+ / HER2+ breast cancer, HR- / HER2+ breast cancer, and triple negative breast cancer (TNBC). In some such embodiments, the breast cancer is androgendependent or AR+ breast cancer. In some such embodiments, the breast cancer is BRCA1- or BRCA2-mutated breast cancer.

[0235]

[0174] In some embodiments, the breast cancer is HR+ / HER2- breast cancer. In some such embodiments, the HR+ / HER2- breast cancer is advanced or metastatic HR+ / HER2- breast cancer. In some embodiments, the HR+ / HER2- breast cancer is early or non-metastatic HR+ / HER2- breast cancer.

[0236]

[0175] In some embodiments, the HR+ / HER2- breast cancer is characterized by amplification or overexpression of CDK4, CDK6 or cyclin D1 (CCND1). In some embodiments, the HR+ / HER2- breast cancer is characterized as RB-positive, RB-proficient, or RB wild type.

[0237]

[0176] In some embodiments, the HR+ / HER2- breast cancer is BRCA1- or BRCA2-mutated breast cancer.

[0238]

[0177] In some embodiments, the HR+ / HER2- breast cancer is PIK3CA-mutated cancer breast cancer.

[0239]

[0178] In some such embodiments, the HR+ / HER2- breast cancer is refractory or resistant to treatment with, or has progressed on, a standard of care agent, e.g., an antiestrogen such as an aromatase inhibitor, a SERD, or a SERM. In some such embodiments, the HR+ / HER2- breast cancer is refractory or resistant to treatment with, or has progressed on, a CDK4 / 6 inhibitor, such as palbociclib or a pharmaceutically acceptable salt thereof.

[0240]

[0179] In some such embodiments, the HR+ / HER2- breast cancer is refractory or resistant to treatment an antiestrogen such as an aromatase inhibitor, a SERD, or a SERM. In some such embodiments, the HR+ / HER2- breast cancer is refractory or resistant to treatment with a CDK4 / 6 inhibitor, such as palbociclib or a pharmaceutically acceptable salt thereof. In some such embodiments, the HR+ / HER2- breast cancer is refractory or resistant to treatment with a CDK4 / 6 inhibitor, such as palbociclib or a pharmaceutically acceptable salt thereof, in further combination with an antiestrogen, e.g., letrozole or fulvestrant.

[0241]

[0180] In some such embodiments, the HR+ / HER2- breast cancer is resistant to treatment an antiestrogen such as an aromatase inhibitor, a SERD, or a SERM. In some such embodiments, the HR+ / HER2- breast cancer is resistant to treatment with a CDK4 / 6 inhibitor, such as palbociclib or a pharmaceutically acceptable salt thereof. In some such embodiments, the HR+ / HER2- breast cancer is resistant to treatment with a CDK4 / 6 inhibitor, such as palbociclib or a pharmaceutically acceptable salt thereof, in further combination with an antiestrogen, e.g., letrozole or fulvestrant.

[0242]

[0181] In some embodiments, the breast cancer is HR+ / HER2+ breast cancer. In some embodiments, the breast cancer is HR- / HER2+ breast cancer.

[0243]

[0182] In some embodiments wherein the breast cancer is HR+, the methods, combinations and uses described herein further comprise an additional anti-cancer agent. In some such embodiments, the additional anti-cancer agent is an antiestrogen, such as an aromatase inhibitor, a SERD, or a SERM. In some such embodiments, the antiestrogen is letrozole or fulvestrant. In some such embodiments, the additional anti-cancer agent is a CDK4 / 6 inhibitor, such as palbociclib or a pharmaceutically acceptable salt thereof. In some such embodiments, the additional anti-cancer agent is a CDK4 / 6 inhibitor, such as palbociclib or a pharmaceutically acceptable salt thereof, in further combination with an antiestrogen, e.g., letrozole or fulvestrant. In some such embodiments, the additional anti-cancer agent is a PI3K inhibitor, e.g., alepelisib.

[0244]

[0183] In some embodiments wherein the breast cancer is HER2+, the methods, combinations and uses described herein further comprise an additional anti-cancer agent. In some such embodiments, the additional anti-cancer agent is a HER2-targeted agent, e.g., trastuzumab emtansine, fam-trastuzumab deruxtecan, pertuzumab, lapatinib, neratinib or tucatinib, or an agent targeting the PI3K / AKT / mTOR molecular pathway, e.g., ipatasertib.

[0245]

[0184] In some embodiments, the breast cancer is triple negative breast cancer (TNBC). In some embodiments, the TNBC is androgen-dependent or AR+ TNBC. In some such embodiments, the TNBC is RN+ or RB-proficient. In some such embodiments, the TNBC is AR+, RB+ or AR+, RB-proficient TNBC.

[0246]

[0185] In some such embodiments, the TNBC is locally recurrent / advanced or metastatic TNBC. In some such embodiments, the TNBC is advanced or metastatic TNBC. In some such embodiments, the TNBC is early or non-metastatic TNBC.

[0247]

[0186] In some embodiments, the TNBC is characterized by amplification or overexpression of CDK4, CDK6 or cyclin D1 (CCND1).

[0248]

[0187] In some embodiments, the TNBC is BRCA1- or BRCA2-mutated TNBC.

[0249]

[0188] In some embodiments, the TNBC is refractory or resistant to treatment with, or has progressed on, a standard of care agent, e.g., an antineoplastic chemotherapeutic agent such as a taxane, platinum agent, anthracycline or anti-metabolite.

[0250]

[0189] In some embodiments of each of the methods, combinations and uses described herein, the cancer is lung cancer. In some embodiments, the lung cancer is non-small_cell lung cancer (NSCLC). In some embodiments, the lung cancer is small cell lung cancer (SCLC). In some such embodiments, the lung cancer is advanced or metastatic lung cancer.

[0190] In some embodiments of each of the methods, combinations and uses described herein, the cancer is liver cancer. In some such embodiments the liver cancer is hepatocellular carcinoma (HCC). In some such embodiments, the liver cancer is advanced or metastatic liver cancer.

[0251]

[0191] In some embodiments of each of the methods, combinations and uses described herein, the cancer is kidney cancer. In some such embodiments the kidney cancer is renal cell carcinoma (RCC). In some such embodiments, the kidney cancer is advanced or metastatic kidney cancer.

[0252]

[0192] In some embodiments of each of the methods, combinations and uses described herein, the cancer is bladder cancer. In some such embodiments the bladder cancer is a urothelial carcinoma, including an upper urinary tract urothelial carcinoma (UUTIIC). In some such embodiments, the bladder cancer is advanced or metastatic bladder cancer.

[0253]

[0193] In some embodiments of each of the methods, combinations and uses described herein, the cancer is ovarian cancer, including epithelial ovarian cancer (EOC). In some such embodiments, the ovarian cancer is advanced or metastatic ovarian cancer.

[0254]

[0194] In some embodiments of each of the methods, combinations and uses described herein, the cancer is peritoneal cancer, including primary peritoneal cancer (PPC). In some such embodiments, the peritoneal cancer is advanced or metastatic peritoneal cancer.

[0255]

[0195] In some embodiments of each of the methods, combinations and uses described herein, the cancer is fallopian tube cancer. In some such embodiments, the fallopian tube cancer is advanced or metastatic fallopian tube cancer.

[0256]

[0196] In some embodiments of each of the methods, combinations and uses described herein, the cancer is cervical cancer. In some such embodiments, the cervical cancer is advanced or metastatic cervical cancer.

[0257]

[0197] In some embodiments of each of the methods, combinations and uses described herein, the cancer is uterine cancer, including endometrial cancer. In some such embodiments, the uterine cancer is advanced or metastatic uterine cancer.

[0258]

[0198] In some embodiments of each of the methods, combinations and uses described herein, the cancer is pancreatic cancer. In some such embodiments, the pancreatic cancer is advanced or metastatic pancreatic cancer. In some such embodimetns, the pancreatic cancer is resistant to antineoplastic chemotherapeutic agents such as taxanes, platinum agent, a nth racy clines or anti-metabolites. In some such embodiments, the pancreatic cancer is resistant to gemcitabine or nab-paclitaxel.

[0259]

[0199] In some embodiments of each of the methods, combinations and uses described herein, the cancer is stomach cancer (or gastric cancer). In some such embodiments, the stomach cancer is adenocarcinoma. In some such embodiments, the stomach cancer is advanced or metastatic stomach cancer.

[0260]

[0200] In some embodiments of each of the methods, combinations and uses described herein, the cancer is colorectal cancer. In some such embodiments, the colorectal cancer is advanced or metastatic colorectal cancer.

[0261]

[0201] In some embodiments of each of the methods, combinations and uses described herein, the cancer is esophageal cancer. In some such embodiments, the esophageal cancer is advanced or metastatic esophageal cancer.

[0262]

[0202] In some embodiments of each of the methods, combinations and uses described herein, the cancer is head and neck cancer. In some such embodiments, the head and neck cancer is advanced or metastatic head and neck cancer. In some such embodiments, the head and neck cancer is squamous cell carcinoma of the head and neck (SCCHN), thyroid cancer, or salivary gland cancer. In some such embodiments the head and neck cancer is salivary gland cancer.

[0263]

[0203] In some embodiments of each of the methods, combinations and uses described herein, the cancer is testicular cancer. In some such embodiments, the testicular cancer is advanced or metastatic testicular cancer.

[0264]

[0204] In some embodiments of each of the methods, combinations and uses described herein, the cancer is adrenal cancer. In some such embodiments, the adrenal cancer is advanced or metastatic adrenal cancer.

[0265]

[0205] In some embodiments of each of the methods, combinations and uses described herein, the cancer is skin cancer. In some such embodiments, the skin cancer is basal cell carcinoma or melanoma. In some such embodiments, the skin cancer is advanced or metastatic skin cancer.

[0266]

[0206] In some embodiments of each of the methods, combinations and uses described herein, the cancer is brain cancer. In some such embodiments, the brain cancer is astrocytoma, meningioma, or glioblastoma. In some such embodiments, the brain cancer is advanced or metastatic brain cancer.

[0267]

[0207] In some embodiments of each of the methods, combinations and uses described herein, the cancer is sarcoma. In some such embodiments, the sarcoma is osteosarcoma or liposarcoma

[0268]

[0208] In some embodiments of each of the methods, combinations and uses described herein, the cancer is lymphoma. In some such embodiments, the lymphoma is mantle cell lymphoma (MCL). Pharmaceutical Compositions, Medicaments and Kits

[0269]

[0209] In some embodiments, this disclosure relates to a pharmaceutical composition comprising a CDK4 inhibitor of Formula (I), and a monoclonal antibody or an antibody-drug conjugate, and a pharmaceutically acceptable carrier.

[0270]

[0210] The present disclosure further provides pharmaceutical compositions, medicaments and kits comprising a compound of Formula (I), having the structure:

[0271] R1is H, F, or Cl;

[0272] R2is C1-C4 alkyl, where said C1-C4 alkyl is optionally substituted by R5;

[0273] R3is H or C1-C4 alkyl, where said C1-C4 alkyl is optionally substituted by R6;

[0274] R4is H or F; and each of R5and R6is independently OH, F, or C1-C2 alkoxy.

[0275]

[0211] In some embodiments, the disclosure provides a pharmaceutical composition comprising a CDK4 inhibitor of Formula (I) or a pharmaceutically acceptable salt thereof, an antiandrogen or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier or excipient.

[0276]

[0212] In some embodiments, the disclosure provides a first pharmaceutical composition comprising a CDK4 inhibitor of Formula (I), and a pharmaceutically acceptable carrier or excipient, and a second pharmaceutical composition comprising a monoclonal antibody or an antibody-drug conjugate, and a pharmaceutically acceptable carrier or excipient, wherein the first and second pharmaceutical compositions are administered sequentially, simultaneously or concurrently.

[0277]

[0213] In some embodiments, the disclosure provides a combination comprising a CDK4 inhibitor of Formula (I), and a monoclonal antibody or an antibody-drug conjugate, for use in the manufacture of a medicament for treating cancer in a subject. In another aspect, the disclosure provides use of a combination comprising a CDK4 inhibitor of Formula (I), and a monoclonal antibody or an antibody-drug conjugate, in the manufacture of a medicament for treating cancer in a subject.

[0214] In some embodiments of the pharmaceutical compositions and medicaments described herein, the compound of Formula (I) is 1,5-anhydro-3-({5-chloro-4-[4-fluoro-2-(2-hydroxypropan- 2-yl)-1-(propan-2-yl)-1 / 7-benzimidazol-6-yl]pyrimidin-2-yl}amino)-2,3-dideoxy-D-f / 7reo-pentitol (PF-07220060).

[0278]

[0215] In some embodiments of each of pharmaceutical compositions and medicaments described herein, the CDK4 inhibitor of Formula (I) is 1,5-anhydro-3-({5-chloro-4-[4-fluoro-2-(2- hydroxypropan-2-yl)-1-(propan-2-yl)-1 / 7-benzimidazol-6-yl]pyrimidin-2-yl}amino)-2,3-dideoxy-D- f / ireo-pentitol (PF-07220060), and the antibody-drug conjugate has the general formula Ab-(L- D)p, in which Ab represents the antibody or functional fragments thereof (e.g., Ab1, Ab2 described herein), L represents a linker, D represents a therapeutic agent, and p is 1 to 8.

[0279]

[0216] In some embodiments of each of pharmaceutical compositions and medicaments described herein, the CDK4 inhibitor of Formula (I) is 1,5-anhydro-3-({5-chloro-4-[4-fluoro-2-(2- hydroxypropan-2-yl)-1-(propan-2-yl)-1 / 7-benzimidazol-6-yl]pyrimidin-2-yl}amino)-2,3-dideoxy-D- f / ireo-pentitol (PF-07220060), and the antibody-drug conjugate has the formula: wherein Ab1 is an antibody that binds to HER2 and comprises:

[0280] (1) a heavy chain variable region comprising a CDR-H1, CDR-H2, and CDR-H3, wherein the CDR-H1 , CDR-H2, and CDR-H3 comprise the amino acid sequences of SEQ ID NOs: 2, 3, and 4, respectively; and

[0281] (2) a light chain variable region comprising a CDR-L1, CDR-L2, and CDR-L3, wherein the CDR-L1, CDR-L2, and CDR-L3 comprise the amino acid sequences of SEQ ID NOs: 8, 9, and 10, respectively; and wherein p is 1 to 4.

[0282]

[0217] In some embodiments of each of pharmaceutical compositions and medicaments described herein, the CDK4 inhibitor of Formula (I) is 1,5-anhydro-3-({5-chloro-4-[4-fluoro-2-(2- hydroxypropan-2-yl)-1-(propan-2-yl)-1 / 7-benzimidazol-6-yl]pyrimidin-2-yl}amino)-2,3-dideoxy-D- f / ireo-pentitol (PF-07220060), and the antibody-drug conjugate comprises Ab2 which is conjugated with a therapeutic agent (D2) via a linker (Linker2), wherein Ab2 is an antibody that binds to HER2 and comprises:

[0283] (1) a heavy chain variable region comprising a CDR-H1, CDR-H2, and CDR-H3, in which the CDR-H1 comprises the amino acid sequence of SEQ ID NO: 31, the CDR-H2 comprises the amino acid sequence of SEQ ID NO: 33, and the CDR-H3 comprises the amino acid sequence of SEQ ID NO: 34 or 35; and

[0284] (2) a light chain variable region comprising a CDR-L1, CDR-L2, and CDR-L3, in which the CDR-L1 , CDR-L2, and CDR-L3 comprise the amino acid sequences of SEQ ID NOs: 36, 37, and 38, respectively; wherein D2 is selected from MMAE and MMAF; and wherein Linker2 is linked with Ab2, optionally through thiol, and is selected from mc-vc- pAB and me.

[0285]

[0218] In some embodiments, the disclosure provides a kit comprising a first container, a second container and a package insert, wherein the first container comprises at least one dose of a CDK4 inhibitor of Formula (I) as described herein; the second container comprises at least one dose of a monoclonal antibody or an antibody-drug conjugate as described herein; and the package insert comprises instructions for treating cancer in a subject using the medicaments.

[0286]

[0219] In some embodiments of the kits herein, the CDK4 inhibitor of Formula (I) is 1,5- anhydro-3-({5-chloro-4-[4-fluoro-2-(2-hydroxypropan-2-yl)-1-(propan-2-yl)-1 / 7-benzimidazol-6- yl]pyrimidin-2-yl}amino)-2,3-dideoxy-D-f / 7reo-pentitol (PF-07220060), and the antibody-drug conjugate has the formula: wherein Ab1 is an antibody that binds to HER2 and comprises:

[0287] (1) a heavy chain variable region comprising a CDR-H1, CDR-H2, and CDR-H3, wherein the CDR-H1 , CDR-H2, and CDR-H3 comprise the amino acid sequences of SEQ ID NOs: 2, 3, and 4, respectively; and

[0288] (2) a light chain variable region comprising a CDR-L1, CDR-L2, and CDR-L3, wherein the CDR-L1, CDR-L2, and CDR-L3 comprise the amino acid sequences of SEQ ID NOs: 8, 9, and 10, respectively; and wherein p is 1 to 4.

[0289]

[0220] In some embodiments of the kits herein, the CDK4 inhibitor of Formula (I) is 1 ,5- anhydro-3-({5-chloro-4-[4-fluoro-2-(2-hydroxypropan-2-yl)-1-(propan-2-yl)-1 / 7-benzimidazol-6- yl]pyrimidin-2-yl}amino)-2,3-dideoxy-D-f / 7reo-pentitol (PF-07220060), and the antibody-drug conjugate comprises Ab2 which is conjugated with a drug payload (D2) via a linker (Linker2), wherein Ab2 is an antibody that binds to HER2 and comprises: (1) a heavy chain variable region comprising a CDR-H1, CDR-H2, and CDR-H3, in which the CDR-H1 comprises the amino acid sequence of SEQ ID NO: 31, the CDR-H2 comprises the amino acid sequence of SEQ ID NO: 33, and the CDR-H3 comprises the amino acid sequence of SEQ ID NO: 34 or 35; and

[0290] (2) a light chain variable region comprising a CDR-L1, CDR-L2, and CDR-L3, in which the CDR-L1 , CDR-L2, and CDR-L3 comprise the amino acid sequences of SEQ ID NOs: 36, 37, and 38, respectively; wherein D2 is selected from MMAE and MMAF; and wherein Linker2 is linked with Ab2, optionally through thiol, and is selected from mc-vc- pAB and me.

[0291]

[0221] In some embodiments of the pharmaceutical compositions, medicaments, and kits comprising an additional anti-cancer agent, the additional anti-cancer agent is an endocrine therapeuticagent, such as an aromatase inhibitor, a SERD, or a SERM. In some such embodiments, the antiestrogen is letrozole or fulvestrant.

[0292]

[0222] The pharmaceutical compositions, medicaments and kits described herein may be useful for treating the cancers described above with respect to the methods, combinations and uses of the disclosure.

[0293] Dosage Forms and Regimens

[0294]

[0223] Each therapeutic agent of the methods and combination therapies of the present disclosure may be administered either alone, or in a medicament (also referred to herein as a pharmaceutical composition) which comprises the therapeutic agent and one or more pharmaceutically acceptable carriers, excipients, or diluents, according to pharmaceutical practice.

[0295]

[0224] As used herein, the terms “combination” or “combination therapy” refer to the administration of two or more therapeutic agents of the combination therapy of the disclosure, either alone or in the form of a pharmaceutical composition or medicament, either sequentially, concurrently or simultaneously.

[0296]

[0225] As used herein, the term “sequential” or “sequentially” refers to the administration of each therapeutic agent of the combination therapy of the disclosure, either alone or in a medicament, one after the other, or one or more doses of one therapeutic agent of the combination therapy after one or more doses of another therapeutic agent of the combination therapy, wherein each therapeutic agent can be administered in any order. Sequential administration may be particularly useful when the therapeutic agents in the combination therapy are in different dosage forms, for example, one agent is a tablet and another agent is a sterile liquid, and / or the agents are administered according to different dosing schedules, for example, one agent is administered daily, and the second agent is administered less frequently such as weekly.

[0297]

[0226] As used herein, the term “concurrent” or “concurrently” refers to the administration of each therapeutic agent in the combination therapy of the disclosure, either alone or in separate medicaments, wherein the second therapeutic agent is administered immediately after the first therapeutic agent, but that the therapeutic agents can be administered in any order. In an embodiment, the therapeutic agents are administered concurrently.

[0298]

[0227] As used herein, the term “simultaneous” or “simultaneously” refers to the administration of each therapeutic agent of the combination therapy of the disclosure in the same medicament, for example as a fixed dose combination comprising two or more drugs in a single dosage form.

[0299]

[0228] In one embodiment of the present disclosure, PF-07220060 is administered before administration of the monoclonal antibody or antibody-drug conjugate.

[0300]

[0229] In one embodiment of the present disclosure, the monoclonal antibody or antibody-drug conjugate is administered before administration of PF-07220060.

[0301]

[0230] In one embodiment of the present disclosure, PF-07220060 is administered concurrently with the monoclonal antibody or antibody-drug conjugate.

[0302]

[0231] In one embodiment of the present disclosure, PF-07220060 is administered simultaneously with the monoclonal antibody or antibody-drug conjugate.

[0303]

[0232] As will be understood by those skilled in the art, the combination therapy may be usefully administered to a subject during different stages of their treatment.

[0304]

[0233] In some embodiments of each of the methods, combinations and uses described herein, the combination therapy is administered to a subject who is previously untreated, i.e. the subject is treatment naive.

[0305]

[0234] In one embodiment of the present disclosure, the combination therapy is administered to a subject who has previously received a CDK4 or CDK4 / 6 inhibitor. In some such embodiments, the combination therapy is administered to a subject who has previously received a CDK4 or CDK4 / 6 inhibitor, but whose cancer has since progressed.

[0306]

[0235] Dosage regimens may be adjusted to provide the optimum desired response. For example, a therapeutic agent of the combination therapy of the present disclosure may be administered as a single bolus, as several divided doses administered over time, or the dose may be proportionally reduced or increased as indicated by the exigencies of the therapeutic situation. It may be particularly advantageous to formulate a therapeutic agent in a dosage unit form for ease of administration and uniformity of dosage. Dosage unit form, as used herein, refers to physically discrete units suited as unitary dosages for the mammalian subjects to be treated; each unit containing a predetermined quantity of active compound calculated to produce the desired therapeutic effect in association with the required pharmaceutical carrier. The specification for the dosage unit forms of the disclosure may be dictated by and directly dependent on (a) the unique characteristics of the chemotherapeutic agent and the particular therapeutic or prophylactic effect to be achieved, and (b) the limitations inherent in the art of compounding such an active compound for the treatment of sensitivity in individuals.

[0307]

[0236] Thus, the skilled artisan would appreciate, based upon the disclosure provided herein, that the dose and dosing regimen is adjusted in accordance with methods well-known in the therapeutic arts. That is, the maximum tolerable dose may be readily established, and the effective amount providing a detectable therapeutic benefit to a subject may also be determined, as can the temporal requirements for administering each agent to provide a detectable therapeutic benefit to the subject. Accordingly, while certain dose and administration regimens are exemplified herein, these examples in no way limit the dose and administration regimen that may be provided to a subject in practicing the present disclosure.

[0308]

[0237] It is to be noted that dosage values may vary with the type and severity of the condition to be alleviated and may include single or multiple doses. It is to be further understood that for any particular subject, specific dosage regimens should be adjusted over time according to the individual need and the professional judgment of the person administering or supervising the administration of the compounds or pharmaceutical compositions, taking into consideration factors such as the severity of the disorder or condition, the rate of administration, the disposition of the compound and the discretion of the prescribing physician. The dosage ranges set forth herein are exemplary only and are not intended to limit the scope or practice of the claimed compound or pharmaceutical composition. For example, doses may be adjusted based on pharmacokinetic or pharmacodynamic parameters, which may include clinical effects such as toxic effects and / or laboratory values. Thus, the present disclosure encompasses intrapatient dose-escalation as determined by the skilled artisan. Determining appropriate dosages and regimens for administration of the chemotherapeutic agent are well-known in the relevant art and would be understood to be encompassed by the skilled artisan once provided the teachings disclosed herein

[0309]

[0238] In some embodiments, at least one of the therapeutic agents in the combination therapy is administered using the same dosage regimen (dose, frequency and duration of treatment) that is typically employed when the agent is used as a monotherapy for treating the same cancer. In other embodiments, the subject received a lower total amount of at least one of the therapeutic agents in the combination therapy than when the same agent is used as a monotherapy, for example a lower dose of therapeutic agent, a reduced frequency of dosing and / or a shorter duration of dosing.

[0310]

[0239] In an embodiment, the CDK4 inhibitor 1,5-anhydro-3-({5-chloro-4-[4-fluoro-2-(2- hydroxypropan-2-yl)-1-(propan-2-yl)-1 / 7-benzimidazol-6-yl]pyrimidin-2-yl}amino)-2,3-dideoxy-D- f / ireo-pentitol, or a pharmaceutically acceptable salt thereof, is administered at a daily dosage of from about 1 mg to about 1000 mg per day. In another embodiment, the CDK4 inhibitor is administered at a daily dosage from about 10 mg to about 500 mg per day. In another embodiment, the CDK4 inhibitor is administered at a dosage of from about 25 mg to about 300 mg per day. In another embodiment the CDK4 inhibitor is administered at dosages of about: 1 , 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210, 215, 220, 225, 230, 235, 240, 245, 250, 260, 270, 275, 280, 290, 300, 325, 350, 375, 400, 425, 450, 475 or 500 mg on a single dose (QD), twice daily (BID), three times daily (TID) or four times daily (QID) schedule.

[0311]

[0240] Repetition of the administration or dosing regimens may be conducted as necessary to achieve the desired reduction or diminution of cancer cells. A “continuous dosing schedule”, as used herein, is an administration or dosing regimen without dose interruptions, e.g., without days off treatment. Repetition of 28-day treatment cycles without dose interruptions between the treatment cycles is an example of a continuous dosing schedule. In an embodiment, the compounds of the combination of the present disclosure may be administered in a continuous dosing schedule. In an embodiment, the compounds of the combination of the present disclosure may be administered concurrently in a continuous dosing schedule.

[0312]

[0241] In one embodiment of the present disclosure, PF-07220060 and the monoclonal antibody or the antibody-drug conjugate as described herein, are dosed in amounts which together are effective in treating the cancer.

[0313]

[0242] In one embodiment of the present disclosure, PF-07220060 the monoclonal antibody or the antibody-drug conjugate as described herein, are dosed in amounts which together are synergistic.

[0314]

[0243] In one embodiment of the present disclosure, PF-07220060 and the antibody-drug conjugate conjugate having the formula: wherein Ab1 is an antibody that binds to HER2 and comprises:

[0315] (1) a heavy chain variable region comprising a CDR-H1, CDR-H2, and CDR-H3, wherein the CDR-H1 , CDR-H2, and CDR-H3 comprise the amino acid sequence of SEQ ID NOs: 2, 3, and 4, respectively; and (2) a light chain variable region comprising a CDR-L1, CDR-L2, and CDR-L3, wherein the CDR-L1, CDR-L2, and CDR-L3 comprise the amino acid sequences of SEQ ID NOs: 8, 9, and 10, respectively; and wherein p is 1 to 4; are dosed in amounts which together are synergistic.

[0316]

[0244] In one embodiment of the present disclosure, PF-07220060 and the antibody-drug conjugate that comprises Ab2 which is conjugated with a therapeutic agent (D2) via a linker (Linker2), wherein Ab2 is an antibody that binds to HER2 and comprises:

[0317] (1) a heavy chain variable region comprising a CDR-H1, CDR-H2, and CDR-H3, in which the CDR-H1 comprises the amino acid sequence of SEQ ID NO: 31, the CDR-H2 comprises the amino acid sequence of SEQ ID NO: 33, and the CDR-H3 comprises the amino acid sequence of SEQ ID NO: 34 or 35; and

[0318] (2) a light chain variable region comprising a CDR-L1 , CDR-L2, and CDR-L3, in which the CDR-L1 , CDR-L2, and CDR-L3 comprise the amino acid sequences of SEQ ID NOs: 36, 37, and 38, respectively; wherein D2 is selected from MMAE and MMAF; and wherein Linker2 is linked with Ab2, optionally through thiol, and is selected from mc-vc- pAB and me; are dosed in amounts which together are synergistic.

[0319] Pharmaceutical Compositions and Routes of Administration

[0320]

[0245] A "pharmaceutical composition" refers to a mixture of one or more of the therapeutic agents described herein, or a pharmaceutically acceptable salt, solvate, hydrate or prodrug thereof as an active ingredient, and at least one pharmaceutically acceptable carrier or excipient. In some embodiments, the pharmaceutical composition comprises two or more pharmaceutically acceptable carriers and / or excipients.

[0321]

[0246] As used herein, a "pharmaceutically acceptable carrier" refers to a carrier or diluent that does not cause significant irritation to an organism and does not abrogate the biological activity and properties of the active compound or therapeutic agent.

[0322]

[0247] The pharmaceutical acceptable carrier may comprise any conventional pharmaceutical carrier or excipient. The choice of carrier and / or excipient will to a large extent depend on factors such as the particular mode of administration, the effect of the excipient on solubility and stability, and the nature of the dosage form.

[0323]

[0248] Suitable pharmaceutical carriers include inert diluents or fillers, water and various organic solvents (such as hydrates and solvates). The pharmaceutical compositions may, if desired, contain additional ingredients such as flavorings, binders, excipients and the like.

[0324] Thus, for oral administration, tablets containing various excipients, such as citric acid may be employed together with various disintegrants such as starch, alginic acid and certain complex silicates and with binding agents such as sucrose, gelatin and acacia. Examples, without limitation, of excipients include calcium carbonate, calcium phosphate, various sugars and types of starch, cellulose derivatives, gelatin, vegetable oils and polyethylene glycols. Additionally, lubricating agents such as magnesium stearate, sodium lauryl sulfate and talc are often useful for tableting purposes. Solid pharmaceutical compositions of a similar type may also be employed in soft and hard filled gelatin capsules. Non-limiting examples of materials, therefore, include lactose or milk sugar and high molecular weight polyethylene glycols. When aqueous suspensions or elixirs are desired for oral administration the active compound therein may be combined with various sweetening or flavoring agents, coloring matters or dyes and, if desired, emulsifying agents or suspending agents, together with diluents such as water, ethanol, propylene glycol, glycerin, or combinations thereof.

[0325]

[0249] The pharmaceutical composition may, for example, be in a form suitable for oral administration as a tablet, capsule, pill, powder, sustained release formulation, solution or suspension, for parenteral injection as a sterile solution, suspension or emulsion, for topical administration as an ointment or cream, or for rectal administration as a suppository.

[0326]

[0250] Exemplary parenteral administration forms include solutions or suspensions of an active compound in a sterile aqueous solution, for example, aqueous propylene glycol or dextrose solutions. Such dosage forms may be suitably buffered, if desired.

[0327]

[0251] The pharmaceutical composition may be in unit dosage forms suitable for single administration of precise amounts.

[0328]

[0252] Pharmaceutical compositions suitable for the delivery of the therapeutic agents of the combination therapies of the present disclosure, and methods for their preparation will be readily apparent to those skilled in the art. Such pharmaceutical compositions and methods for their preparation may be found, for example, in ‘Remington’s Pharmaceutical Sciences’, 19th Edition (Mack Publishing Company, 1995), the disclosure of which is incorporated herein by reference in its entirety.

[0329]

[0253] Therapeutic agents of the combination therapies of the disclosure may be administered orally. Oral administration may involve swallowing, so that the therapeutic agent enters the gastrointestinal tract, or buccal or sublingual administration may be employed by which the therapeutic agent enters the blood stream directly from the mouth.

[0330]

[0254] Formulations suitable for oral administration include solid formulations such as tablets, capsules containing particulates, liquids, or powders, lozenges (including liquid-filled), chews, multi- and nano-particulates, gels, solid solution, liposome, films (including muco-adhesive), ovules, sprays and liquid formulations.

[0331]

[0255] Liquid formulations include suspensions, solutions, syrups and elixirs. Such formulations may be used as fillers in soft or hard capsules and typically include a carrier, for example, water, ethanol, polyethylene glycol, propylene glycol, methylcellulose, or a suitable oil, and one or more emulsifying agents and / or suspending agents. Liquid formulations may also be prepared by the reconstitution of a solid, for example, from a sachet.

[0332]

[0256] Therapeutic agents of the combination therapies of the present disclosure may also be used in fast-dissolving, fast-disintegrating dosage forms such as those described in Expert Opinion in Therapeutic Patents, 11 (6), 981-986 by Liang and Chen (2001), the disclosure of which is incorporated herein by reference in its entirety.

[0333]

[0257] For tablet dosage forms, the therapeutic agent may make up from 1 wt% to 80 wt% of the dosage form, more typically from 5 wt% to 60 wt% of the dosage form. In addition to the active agent, tablets generally contain a disintegrant. Examples of disintegrants include sodium starch glycolate, sodium carboxymethyl cellulose, calcium carboxymethyl cellulose, croscarmellose sodium, crospovidone, polyvinylpyrrolidone, methyl cellulose, microcrystalline cellulose, lower alkyl-substituted hydroxypropyl cellulose, starch, pregelatinized starch and sodium alginate. Generally, the disintegrant may comprise from 1 wt% to 25 wt%, preferably from 5 wt% to 20 wt% of the dosage form.

[0334]

[0258] Binders are generally used to impart cohesive qualities to a tablet formulation. Suitable binders include microcrystalline cellulose, gelatin, sugars, polyethylene glycol, natural and synthetic gums, polyvinylpyrrolidone, pregelatinized starch, hydroxypropyl cellulose and hydroxypropyl methylcellulose. Tablets may also contain diluents, such as lactose (monohydrate, spray-dried monohydrate, anhydrous and the like), mannitol, xylitol, dextrose, sucrose, sorbitol, microcrystalline cellulose, starch and dibasic calcium phosphate dihydrate.

[0335]

[0259] Tablets may also optionally include surface active agents, such as sodium lauryl sulfate and polysorbate 80, and glidants such as silicon dioxide and talc. When present, surface active agents are typically in amounts of from 0.2 wt% to 5 wt% of the tablet, and glidants typically from 0.2 wt% to 1 wt% of the tablet.

[0336]

[0260] Tablets also generally contain lubricants such as magnesium stearate, calcium stearate, zinc stearate, sodium stearyl fumarate, and mixtures of magnesium stearate with sodium lauryl sulphate. Lubricants generally are present in amounts from 0.25 wt% to 10 wt%, preferably from 0.5 wt% to 3 wt% of the tablet.

[0337]

[0261] Other conventional ingredients include anti-oxidants, colorants, flavoring agents, preservatives and taste-masking agents.

[0338]

[0262] Exemplary tablets may contain from about 1 wt% to about 80 wt% active agent, from about 10 wt% to about 90 wt% binder, from about 0 wt% to about 85 wt% diluent, from about 2 wt% to about 10 wt% disintegrant, and from about 0.25 wt% to about 10 wt% lubricant.

[0339]

[0263] Tablet blends may be compressed directly or by roller to form tablets. Tablet blends or portions of blends may alternatively be wet-, dry-, or melt-granulated, melt congealed, or extruded before tableting. The final formulation may include one or more layers and may be coated or uncoated; or encapsulated.

[0340]

[0264] The formulation of tablets is discussed in detail in “Pharmaceutical Dosage Forms: Tablets, Vol. 1”, by H. Lieberman and L. Lachman, Marcel Dekker, N.Y., N.Y., 1980 (ISBN 0- 8247-6918-X), the disclosure of which is incorporated herein by reference in its entirety.

[0341]

[0265] Capsules (made, for example, from gelatin or HPMC), blisters and cartridges for use in an inhaler or insufflator may be formulated to contain a powder mix of the therapeutic agent, a suitable powder base such as lactose or starch and a performance modifier such as l-leucine, mannitol, or magnesium stearate. The lactose may be anhydrous or in the form of the monohydrate, preferably the latter. Other suitable excipients include dextran, glucose, maltose, sorbitol, xylitol, fructose, sucrose and trehalose.

[0342]

[0266] Solid formulations for oral administration may be formulated to be immediate and / or modified release. Modified release formulations include delayed-, sustained-, pulsed-, controlled-, targeted and programmed release.

[0343]

[0267] Suitable modified release formulations are described in U.S. Patent No. 6,106,864.

[0344] Details of other suitable release technologies such as high energy dispersions and osmotic and coated particles may be found in Verma et al, Current Status of Drug Delivery Technologies and Future Directions, Pharmaceutical Technology On-line, (2001) 25:1-14. The use of chewing gum to achieve controlled release is described in WO 00 / 35298. The disclosures of these references are incorporated herein by reference in their entireties.

[0345]

[0268] Therapeutic agents of the combination therapies of the disclosure may also be administered directly into the blood stream, into muscle, or into an internal organ. Suitable means for parenteral administration include intravenous, intraarterial, intraperitoneal, intrathecal, intraventricular, intraurethral, intrasternal, intracranial, intramuscular and subcutaneous. Suitable devices for parenteral administration include needle (including micro needle) injectors, needle-free injectors and infusion techniques.

[0346]

[0269] Parenteral formulations are typically aqueous solutions which may contain excipients such as salts, carbohydrates and buffering agents (preferably to a pH of from 3 to 9), but, for some applications, they may be more suitably formulated as a sterile non-aqueous solution or as a dried form to be used in conjunction with a suitable vehicle such as sterile, pyrogen-free water.

[0347]

[0270] The preparation of parenteral formulations under sterile conditions, for example, by lyophilization, may readily be accomplished using standard pharmaceutical techniques well known to those skilled in the art.

[0271] The solubility of therapeutic agents used in the preparation of parenteral solutions may potentially be increased by the use of appropriate formulation techniques, such as the incorporation of solubility-enhancing agents.

[0348]

[0272] Formulations for parenteral administration may be formulated to be immediate and / or modified release. Modified release formulations include delayed-, sustained-, pulsed-, controlled-, targeted and programmed release. Thus, therapeutic agents of the combination therapies of the disclosure may potentially be formulated as a solid, semi-solid, or thixotropic liquid for administration as an implanted depot providing modified release of the active compound. Examples of such formulations include drug-coated stents and PGLA microspheres.

[0349]

[0273] The therapeutic agents of the combination therapies of the present disclosure may conveniently be combined in the form of a kit suitable for coadministration of the pharmaceutical compositions. Such kits may comprise one or both of the active agents in the form of a pharmaceutical composition, which pharmaceutical composition comprises an active agent, or a pharmaceutically acceptable salt or solvate thereof, and a pharmaceutically acceptable carrier. The kit may contain means for separately retaining said pharmaceutical compositions, such as a container, divided bottle, or divided foil packet. An example of such a kit is the familiar blister pack used for the packaging of tablets, capsules and the like.

[0350]

[0274] The kits described herein may be particularly suitable for administering different dosage forms, for example, oral and parenteral, for administering the separate pharmaceutical compositions at different dosage intervals, or for titrating the separate pharmaceutical compositions against one another. To assist compliance, the kit typically includes directions for administration and may be provided with a memory aid. The kit may further comprise other materials that may be useful in administering the medicaments, such as diluents, filters, IV bags and lines, needles and syringes, and the like.

[0351]

[0275] Miscellaneous antineoplastic agents include: asparaginase (pegaspargase), bexarotene, eribulin, everolimus, hydroxyurea, ixabepilone, lenalidomide, mitotane, omacetaxine, pomalidomide, tagraxofusp, telotristat, temsirolimus, thalidomide, and venetoclax.

[0352] EXAMPLES

[0353] Materials and Methods:

[0354]

[0276] Spheroid assays were performed in 96 well ultralow attachment plates (ULA-96U) from Nexcelom & Thermo Fisher Scientific. ZR751 , T47D, BT474, LNCaP, C4-2 and C4-2B cells BT474 cells were dispensed in 200 pL of complete growth medium per well (n = 10 to 12 wells per treatment group) of each ultralow attachment plate to allow formation of one spheroid per well with a diameter between 200 and 250 pm before the start of treatment (cell seeding numbers were previously optimized so that formed spheroids possessed this desired dimension). To aid spheroid formation, dispensed cells were centrifuged at 220 x g for 6 minutes in the ultralow attachment plates and allowed to form compact spheroids for 4 days prior to the initiation of treatment. After spheroids were formed, 150 pL of medium was aspirated from each well without disturbing the spheroid, and fresh RPMI medium of the same volume was added containing single agent compounds (palbociclib, PF-07220060, fulvestrant, or Trazimera®), or selected combinations thereof. Final concentrations of each compound in the wells were: 30 nM for palbociclib; 300 nM for PF-07220060; 1 nM for fulvestrant; and 20 pg / ml for Trazimera®. DMSO (0.01 %) was used as the vehicle control. DMSO and all compounds were diluted in cell medium. Medium and compounds were replenished twice per week, with 3 and 4-day intervals. Replenishment was executed by aspirating 150 pL of medium per well without disturbing the spheroid and then adding the same volume of premixed medium / compound solution to spheroids. In some cases, an extended phase of treatment was followed by a ‘recovery’ phase where medium was replenished without addition of compounds. Spheroid diameter was quantified immediately following each medium change twice a week (on every 3rdor 4thday) throughout the duration of the assay.

[0355]

[0277] A sequential treatment schedule was implemented for experiments involving HER2 ADC (PF-06804103) treatment of BT474 spheroids. It was added at Day 0 and Day 24 and medium change was performed twice each week without re-addition of HER2-ADC. Palbociclib or PF- 07220060 was then added for 2 weeks (with each medium change every 2-3 days) one week after each dosing of HER2-ADC in all combination arms. The diameter of the spheroids during and after treatment was measured (Celigo 200-BFFL-S, Nexcelom) at each medium change.

[0356] Data Analysis:

[0357]

[0278] Average diameters of spheroids were plotted in GraphPad Prism 8 and the AUC calculated. AUC baseline was determined by the average tumor spheroid diameter at Day 0 in the vehicle (DMSO) controls. Spheroid growth inhibition, or SGI, was calculated as follows: SGI = (1-AUC treatment / AUC DMSO) x 100%. SGI for all treatment arms was derived at the timepoint when the vehicle (DMSO) treated spheroids reach their maximal diameter (usually close to 1 mm but this can differ among cell lines); this corresponds to the last time point taken for the vehicle (DMSO) treated spheroids. Standard error of measurement (SEM) was calculated based on n = 10 to 12 wells per test group.

[0358]

[0279] Spheroids growth was monitored over time to assess: (i) amplitude of response (spheroid growth inhibition, SGI) and (ii) duration of response to single agents and combination treatments while on treatment. Example 1 : CDK4 Inhibitor Synergized with HER2 Antibody against HR+ BT474 Spheroids Assay

[0359]

[0280] HR+ HER2+ BT474 breast cancer spheroids were treated with 1) vehicle (DMSO), 2) 20 pg / mL HER2 antibody Trazimera® (AB), 3) 30 nM palbociclib (Pa), 4) 300 nM PF-07220060 (60), 5) 30 nM palbociclib + 20 pg / mL Trazimera®, or 6) 300 nM PF-07220060 + 20 pg / mL Trazimera®. FIG. 5 shows the spheroid in vitro growth as spheroid diameter (pm) versus time of treatment. The percent of spheroid growth inhibition (SGI%) is indicated in Table 3 below. Results showed that the combination of 300 nM PF-07220060 and 20 pg / mL Trazimera® was the most effective, inhibiting spheroid growth by 96%, compared to 58% with Trazimera® alone and 65% with Trazimera® plus palbociclib. Error bars represent SEM. Complete spheroid growth inhibition (growth stasis) was obtained with the PF-07220060 and Trazimera® combination.

[0360] Example 2: CDK4 Inhibitor Synergized with HER2 Antibody-Drug Conjugate (ADC) against HR+ BT474 Spheroids Assay

[0361]

[0281] This study demonstrates the effectiveness of sequential treatment of PF-07220060 and an HER2 ADC (such as PF-06804103).

[0362]

[0282] HER2-ADC PF-06804103 comprised of a humanized anti-HER2 monoclonal antibody conjugated to the cytotoxic small molecule Auristatin 0101 via a valine-citrulline dipeptide linker (HER2-ADC), which blocks mitosis in cells expressing HER2. Since CDK4 inhibitors arrest the cell cycle in the G1 phase, and the treatment benefit of HER2-ADC depends on actively cycling cells to enter mitosis, a sequential treatment schedule was used where BT474 spheroids were treated with HER2-ADC and then with PF-07220060 (or palbociclib) in an alternating schedule, as illustrated in FIG. 6. Arrows indicate addition of HER2-ADC antibody to spheroids (on day 0 and 24); CDK inhibitors (PF-07220060 or palbociclib) were administered within two treatment phases only (2 weeks each, grey boxes). Error bars represent SEM.

[0363]

[0283] HR+ HER2+ BT474 breast cancer spheroids were treated with 1) vehicle (DMSO), 2) 10 ng / mL HER2-ADC , 3) 30 nM palbociclib, 4) 300 nM PF-07220060, 5) sequential administration of 30 nM palbociclib and HER2-ADC PF-06804103, or 6) sequential administration of 300 nM PF-07220060 and PF-06804103. FIG. 6 shows the spheroid in vitro growth displaying spheroid diameter (pm) measured over time of treatment. For sequential administration of the combinations, arrows indicate the addition of PF-06804103 to spheroids (on day 0 and 24), and CDK inhibitors were administered within two treatment phases only (2 weeks each, grey boxes). Table 3 shows the percent of spheroid growth inhibition (SGI%). The results indicated that the BT474 SGI increased from 70% HER2-ADC as a single agent to 84% when treated with an alternating treatment schedule that included PF-07220060.

[0284] Table 3. SGI% for single agent and combination treatments

[0364] SGI = (1-AUC treatment / AUC DMSO) x 100%.

[0365] SGIs derived from independent experiments.

[0366] Example 3: CDK4 Inhibitor Synergized with HER2 Antibody-Drug Conjugate (ADC) disitamab vedotin to inhibit proliferation of HR+ cells

[0367]

[0285] This study demonstrates the effectiveness of sequential treatment of CDK4i (PF- 07220060) and the HER2 ADC disitamab vedotin (DV).

[0368]

[0286] HER2-ADC disitamab vedotin is comprised of a humanized anti-HER2 monoclonal antibody conjugated to the cytotoxic small molecule monomethyl auristatin E via a valinecitrulline dipeptide linker (HER2-ADC), which blocks mitosis in cells expressing HER2, as well as neighbouring cells that may or may not express HER2 via bystander activity. Next generation HER2-directed ADCs have demonstrated enhanced activity in HER2 low expressing tumor populations including ER+ breast cancer patients.

[0369]

[0287] To evaluate the efficacy of the combination of DV and PF-07220060, isobologram assays were ran in the ER+ HER2 low breast cancer cell line, CAMA1. These assays allow for many different concentrations of the combination to be evaluated in a single experiment, while also providing single agent activity data. FIG.7 illustrates the schematic of the assay and sequential dosing procedure for PF-07220060 an DV. On Day 1, the cell lines were treated with a five-point dose titration of PF-07220060 at 31.25 nM, 125 nM, 500 nM, 2,000 nM, and 8,000 nM, with control wells being treated with a relevant volume of DMSO. On Day 4, the media was exchanged, the DMSO control and PF-07220060 were replenished, the positive control Brefeldin A was added to the positive control wells at a concentration of 0.5 pM, and DV was added at a nine-point dose dilution, starting at 6000 ng / ml, with sequential 1:3 titrations at 2000ng / ml, 667ng / ml, 222 ng / ml, 74.1 ng / ml, 24.7 ng / ml, 8.23 ng / ml, 2.74 ng / ml and 0.91 ng / ml. The assay was read out on Day 7 with viability being evaluated by a fluorescent marker of DNA content, CyQuant.

[0370]

[0288] FIGs. 8A-8C show the dose response curves illustrating the single agent activity of PF- 07220060 (FIG.8A) and DV (FIG. 8B), along with the combined effect of DV + PF-07220060 (FIG. 8C). Mean + / - SEM, n = 3.

[0371]

[0289] FIG. 9 shows an isobologram for CAMA1 cells treated with PF-07220060 and DV in vitro. The x-axis indicates the concentration of PF-07220060 in pM. The y-axis indicates the concentration of DV in ng / ml. When the experimental curve falls below the straight diagonal line, as is the case here, this represents a synergistic interaction. The synergy score was calculated using the Loewe excess method using Horizon’s proprietary Chalice Analyzer software. (For detailed methods see Kondo et al. 2002).

[0372]

[0290] Additional HR+ breast cancer cell lines (e.g., T47D, ZR751 and JIMT1) were used according to the same assay and sequential dosing procedure described above.

[0373]

[0291] Table 4 summarizes similar experiments conducted across a small panel of breast cancer lines.

[0374]

[0292] Table 4. Summary of combination experiments across a panel of HR+ breast cancer cell lines

[0375]

[0293] In conclusion, it was discovered that the CDK4 inhibitor disclosed herein (e.g., PF- 07220060) can increase the sensitivity of HR+ breast cancer cells to treatment with HER2 antibody and / or HER2-ADC.

[0376]

[0294] All publications and patent applications cited in the specification are herein incorporated by reference in their entirety. Although the foregoing disclosure has been described in some detail by way of illustration and example, it will be readily apparent to those of ordinary skill in the art in light of the teachings of this disclosure that certain changes and modifications may be made thereto without departing from the spirit or scope of the appended claims.

Claims

CLAIMS1. A method of treating cancer in a subject in need thereof comprising administering to the subject an amount of a CDK4 inhibitor in combination with an amount of an anti-HER2 therapeutic agent comprising a monoclonal antibody or an antibody-drug conjugate (ADC); and optionally with an endocrine therapy agent; wherein the CDK4 inhibitor is a compound of Formula (I) or a pharmaceutically acceptable salt thereof:wherein:R1is H, F, or Cl;R2is C1-C4 alkyl, where said C1-C4 alkyl is optionally substituted by R5;R3is H or C1-C4 alkyl, where said C1-C4 alkyl is optionally substituted by R6;R4is H or F; and each of R5and R6is independently OH, F, or C1-C2 alkoxy; wherein the monoclonal antibody is trastuzumab, trastuzumab-qyyp, pertuzumab, margetuximab, zanidatamab, zenocutuzumab, or combinations thereof; wherein the ADC is ADC1 or ADC2: wherein ADC1 has the formula:wherein Ab1 is an antibody that binds to HER2 and comprises:(1) a heavy chain variable region comprising a CDR-H1 , CDR-H2, and CDR-H3, wherein the CDR-H1 , CDR-H2, and CDR-H3 comprise the amino acid sequences of SEQ ID NOs: 2, 3, and 4, respectively; and(2) a light chain variable region comprising a CDR-L1, CDR-L2, and CDR-L3, wherein the CDR-L1, CDR-L2, and CDR-L3 comprise the amino acid sequences of SEQ ID NOs: 8, 9, and 10, respectively; and wherein p is 1 to 4; wherein ADC2 comprises Ab2 which is conjugated with a drug payload (D2) via a linker (Linker2), wherein Ab2 is an antibody that binds to HER2 and comprises:(1) a heavy chain variable region comprising a CDR-H1, CDR-H2, and CDR-H3, in which the CDR-H1 comprises the amino acid sequence of SEQ ID NO: 31, the CDR-H2 comprises the amino acid sequence of SEQ ID NO: 33, and the CDR-H3 comprises the amino acid sequence of SEQ ID NO: 34 or 35; and(2) a light chain variable region comprising a CDR-L1 , CDR-L2, and CDR-L3, in which the CDR-L1 , CDR-L2, and CDR-L3 comprise the amino acid sequences of SEQ ID NOs: 36, 37, and 38, respectively; wherein D2 is selected from MMAE and MMAF; wherein Linker2 is linked with Ab2, optionally through thiol, and Linker2 is selected from mc-vc-pAB and me; and optionally wherein the amounts together are effective in treating the cancer.

2. The method of claim 1, wherein the compound of Formula (I) is 1,5-anhydro-3- ({5-chloro-4-[4-fluoro-2-(2-hydroxypropan-2-yl)-1-(propan-2-yl)-1 / 7-benzimidazol-6-yl]pyrimidin- 2-yl}amino)-2,3-dideoxy-D-f / 7reo-pentitol.

3. The method of any one of claims 1-2, wherein the anti-HER2 therapeutic agent is a monoclonal antibody selected from the group consisting of trastuzumab, trastuzumab-qyyp, pertuzumab, and margetuximab, zanidatamab, and zenocutuzumab.

4. The method of any one of claims 1-3, wherein the anti-HER2 therapeutic agent is a monoclonal antibody which is trastuzumab-qyyp.

5. The method of any one of claims 1-2, wherein the anti-HER2 therapeutic agent is ADC1.

6. The method of any one of claims 1, 2, and 5, wherein the heavy chain variable region of Ab1 comprises an amino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO: 1, and the light chain variable region of Ab1 comprises anamino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO: 7 or 44.

7. The method of any one of claims 1, 2, 5, and 6, wherein the heavy chain variable region of Ab1 comprises the amino acid sequence of SEQ ID NO: 1 , and the light chain variable region of Ab1 comprises the amino acid sequence of SEQ ID NO: 7 or 44.

8. The method of any one of claims 1, 2, and 5-7, wherein Ab1 comprises a heavy chain comprising the heavy chain variable region and a heavy chain constant region, and Ab1 comprises a light chain comprising the light chain variable region and a light chain constant region.

9. The method of claim 8, wherein the heavy chain of Ab1 comprises an amino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO: 6 or 14, and the light chain of Ab1 comprises an amino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO: 12, 16, 45, or 46.

10. The method of any one of claims 8-9, wherein the heavy chain of Ab1 comprises the amino acid sequence of SEQ ID NO: 6 or 14, and the light chain of Ab1 comprises the amino acid sequence of SEQ ID NO: 12, 16, 45, or 46.

11. The method of any one of claims 1, 2, and 5-10 wherein p is 4.

12. A method of treating cancer in a subject in need thereof comprising administering to the subject: an amount of a CDK4 inhibitor that is 1,5-anhydro-3-({5-chloro-4-[4-fluoro-2-(2- hydroxypropan-2-yl)-1-(propan-2-yl)-1 / 7-benzimidazol-6-yl]pyrimidin-2-yl}amino)-2,3-dideoxy-D- f / ireo-pentitol or a pharmaceutically acceptable salt thereof; and an amount of an anti-HER2 therapeutic agent that is an antibody-drug conjugate (ADC) that has the formula:wherein Ab1 is an antibody that binds to HER2 and comprises a heavy chain comprising the amino acid sequence of SEQ ID NO: 6 or 14, and comprises a light chain comprising the amino acid sequence of SEQ ID NO: 12, 16, 45, or 46, wherein p is 4, and optionally wherein the amounts together are effective in treating the cancer.

13. The method of any one of claims 1-2, wherein the anti-HER2 therapeutic agent is ADC2.

14. The method of any one of claims 1, 2, and 13, wherein the heavy chain variable region of Ab2 comprises an amino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO: 39, and the light chain variable region of Ab2 comprises an amino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO: 40.

15. The method of any one of claims 1, 2, 13, and 14, wherein the heavy chain variable region of Ab2 comprises the amino acid sequence of SEQ ID NO: 39, and the light chain variable region of Ab2 comprises the amino acid sequence of SEQ ID NO: 40.

16. The method of any one of claims 1, 2, and 13-15, wherein Ab2 comprises a heavy chain comprising the heavy chain variable region and a heavy chain constant region, and Ab2 comprises a light chain comprising the light chain variable region and a light chain constant region.

17. The method of claim 16, wherein the heavy chain of Ab2 comprises an amino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO: 41 or 42, and the light chain of Ab2 comprises an amino acid sequence that is at least 90%, atleast 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO: 43.

18. The method of any one of claims 16-17, wherein the heavy chain of Ab2 comprises the amino acid sequence of SEQ ID NO: 41 or 42, and the light chain of Ab2 comprises the amino acid sequence of SEQ ID NO: 43.

19. The method of any one of claims 1, 2, and 13-18, wherein D2 is MMAE.

20. The method of any one of claims 1, 2, and 13-19, wherein Linker2 is mc-vc-pAB.

21. The method of any one of claims 1, 2, and 13-18, wherein -Linker2-D2 is selected from the group consisting of mc-vc-pAB-MMAE, mc-vc-pAB-MMAF, and mc-MMAF.

22. A method of treating cancer in a subject in need thereof comprising administering to the subject: an amount of a CDK4 inhibitor that is 1,5-anhydro-3-({5-chloro-4-[4-fluoro-2-(2- hydroxypropan-2-yl)-1-(propan-2-yl)-1 / 7-benzimidazol-6-yl]pyrimidin-2-yl}amino)-2,3-dideoxy-D- f / ireo-pentitol or a pharmaceutically acceptable salt thereof; and an amount of an anti-HER2 therapeutic agent that is an antibody-drug conjugate (ADC) that comprises Ab2 which is conjugated with MMAE via mc-vc-pAB, wherein Ab2 is an antibody that binds to HER2 and comprises a heavy chain comprising the amino acid sequence of SEQ ID NO: 41 or 42, and comprises a light chain comprising the amino acid sequence of SEQ ID NO: 43, and optionally wherein the amounts together are effective in treating the cancer.

23. The method of any one of claims 1-22, wherein the endocrine therapy agent is selected from the group consisting of letrozole, anastrozole, exemestane, fulvestrant, elacestrant, amcenestrant, giredestrant, RG6171, camizestrant, AZD9496, rintodestrant, ZN-c5, LSZ102, D-0502, LY3484356, SHR9549, tamoxifen, raloxifene, toremifene, lasofoxifene, bazedoxifene, and afimoxifene.

24. The method of claim any one of claims 1-23, wherein the endocrine therapy agent is letrozole or fulvestrant.

25. The method of any one of claims 1-24, wherein the cancer is selected from the group consisting of prostate cancer, breast cancer, lung cancer, liver cancer, kidney cancer, bladder cancer, ovarian cancer, peritoneal cancer, fallopian tube cancer, cervical cancer,uterine cancer, pancreatic cancer, stomach cancer, colorectal cancer, esophageal cancer, head and neck cancer, testicular cancer, adrenal cancer, skin cancer, brain cancer, sarcoma, and lymphoma.

26. The method of any one of claims 1-25, wherein the cancer is breast cancer selected from any one or more of: hormone receptor positive (HR+) breast cancer, hormone receptor negative (HR-) breast cancer, human epidermal growth factor receptor 2 negative (HER2-) breast cancer, human epidermal growth factor receptor 2 positive (HER2+) breast cancer, HR+ / HER2- breast cancer, estrogen receptor negative (ER-) / HR+ breast cancer, estrogen receptor positive (ER+) / HER2- breast cancer, and triple negative breast cancer (TNBC).

27. The CDK4 inhibitor and anti-HER2 therapeutic agent for use in the method of any one of claims 1-26.

28. Use of the CDK4 inhibitor and anti-HER2 therapeutic agent for the manufacture of a medicament for the method of any one of claims 1-26.

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