Claims for Patent: 10,239,951

Summary for Patent: 10,239,951

Title:	Bispecific HER2 and HER3 antigen binding constructs
Abstract:	Described herein are isolated bi-specific antigen binding constructs, e.g., antibodies. The bi-specific antigen binding constructs include two antigen binding polypeptide constructs, e.g., a Fab and an scFv. The first antigen-binding polypeptide construct monovalently and specifically binds to extracellular domain 4 (ECD4) of HER2 (human epidermal growth factor receptor 2); the second antigen-binding polypeptide construct monovalently and specifically binds to an extracellular domain (ECD) of HER3 (human epidermal growth factor receptor 3). One antigen binding polypeptide construct is a Fab format and the other antigen binding polypeptide construct is an scFv format. The bi-specific antigen binding constructs includes an Fc having two Fc polypeptides each having a CH3 domain for dimerization. Each Fc polypeptide is linked to the C-terminus of one of the antigen binding polypeptide constructs with or without a linker.
Inventor(s):	Ng; Gordon Yiu Kon (Vancouver, CA), Chan; Peter Wing Yiu (Richmond, CA), Wickman; Grant Raymond (Vancouver, CA)
Assignee:	Zymeworks Inc. (Vancouver, CA)
Application Number:	14/888,580
Patent Claims:	1. An isolated bi-specific antigen binding construct comprising: a first antigen-binding polypeptide construct which monovalently and specifically binds to an extracellular domain 4 (ECD4) of HER2 (human epidermal growth factor receptor 2), the first antigen-binding polypeptide construct comprising three variable heavy chain CDRs comprising the sequences set forth in SEQ ID NOs:49, 50, and 51, and three variable light chain CDRs comprising the sequences set forth in SEQ ID NOs:52, 53, and 54; a second antigen-binding polypeptide construct which monovalently and specifically binds to an extracellular domain (ECD) of HER3 (human epidermal growth factor receptor 3), the antigen-binding polypeptide construct comprising three variable heavy chain CDRs comprising the sequences set forth in SEQ ID NOs: 58, 59, and 60, and three variable light chain CDRs comprising the sequences DVS and as set forth in SEQ ID NOs:62 and 63; and an Fc comprising a first Fc polypeptide comprising a first CH3 domain and a second Fc polypeptide comprising a second CH3 domain, the first Fc polypeptide linked to the C-terminus of the first antigen-binding polypeptide construct with or without a linker and the second Fc polypeptide linked to the C-terminus of the second antigen-binding polypeptide construct with or without a linker; wherein the first antigen-binding polypeptide construct is a Fab format and the second antigen-binding polypeptide construct is an scFv format; and wherein the isolated bi-specific antigen binding construct has a geometry that allows the first antigen-binding polypeptide construct and the second antigen-binding polypeptide construct to each bind its respective extracellular domain and exhibit greater inhibition of heregulin-stimulated growth of BT-474 cells in vitro as compared to a control, wherein the control is v880 as described in FIG. 10. 2. The isolated bi-specific antigen binding construct of claim 1, wherein i. the first antigen-binding polypeptide construct is a Fab format comprising a first VH comprising the amino acid sequence set forth in SEQ ID NO:55 and a first VL comprising the amino acid sequence set forth in SEQ ID NO:56; and ii. the second antigen binding polypeptide construct in an scFv format comprising a second VH comprising the amino acid sequence set forth in SEQ ID NO:57 and a second VL comprising the amino acid sequence set forth in SEQ ID NO:61. 3. The isolated bi-specific antigen binding construct of claim 1, wherein the antigen-binding polypeptide construct in the scFv format is stabilized by addition of a disulphide bond between the VH and VL sequences, or by decreasing the surface hydrophobicity of the scFv. 4. The isolated bi-specific antigen binding construct of claim 1, wherein the Fc is derived from the Fc of an IgG1, IgG2, IgG3, IgG4, IgA or IgE antibody, or of an IgG subclass including IgG1, IgG2, IgG3, or IgG4, or a combination thereof. 5. The isolated bi-specific antigen binding construct of claim 1, wherein at least one CH3 domain comprises at least one amino acid modification that promotes the formation of a heterodimeric Fc with stability comparable to a wild-type homodimeric Fc. 6. The isolated bi-specific antigen binding construct of claim 5, wherein the dimerized CH3 domains of the heterodimeric Fc have a melting temperature (Tm) as measured by differential scanning calorimetry (DSC) of about 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 77.5, 78, 79, 80, 81, 82, 83, 84, or 85.degree. C. or higher, and/or wherein the heterodimeric Fc is formed with a purity greater than about 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99% when produced; or wherein the heterodimeric Fc is formed with a purity greater than about 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99% when expressed or when expressed via a single cell. 7. The isolated bi-specific antigen binding construct of claim 1, wherein the bi-specific antigen binding construct i. inhibits active HER2-HER3 heterodimer signaling by 50-100%; ii. inhibits EGFR-HER3 heterodimer signaling by at least 50%; iii. blocks heregulin-stimulated signaling of HER3 by up to 100%; iv. inhibits the growth of cancer cells in the presence or absence of growth factor; v. inhibits the growth of cancer cells in the presence of heregulin; vi. is internalized by cancer cells expressing HER2 and/or HER3; vii. exhibits increased internalization compared to the reference bivalent monospecific antibody in cancer cells co-expressing HER2 and HER3; viii. mediates increased ADCC towards HER2 and/or HER3 expressing cancer cells compared to the reference antibody; ix. mediates increased ADCC towards HER2 and/or HER3 expressing breast cancer cells, ovarian cancer cells, and gastric cancer cells; x. mediates increased ADCC towards HER2 and/or HER3 expressing breast cancer cells selected from high HER2 expressing cells, medium HER2 expressing cells, low HER2 expressing cells, triple negative breast cancer cells, estrogen receptor-positive breast cancer cells, and trastuzumab-resistant breast cancer cells; and/or xi. mediates increased ADCC towards HER2 and/or HER3 expressing cancer cells comprising a mutation known to cause cancer. 8. The isolated bi-specific antigen binding construct of claim 1, wherein the bi-specific antigen binding construct is afucosylated. 9. The isolated bi-specific antigen binding construct of claim 1, wherein the bi-specific antigen-binding construct is conjugated to a detectable label or a drug. 10. The isolated bi-specific antigen binding construct of claim 9, wherein the detectable label is a radioactive compound, a fluorescent compound, an enzyme, a substrate, an epitope tag, or a toxin. 11. The isolated bi-specific antigen binding construct of claim 9, wherein the drug is a toxin, a chemotherapeutic agent, an immune modulator, or a radioisotope. 12. The isolated bi-specific antigen binding construct of claim 9, wherein the drug is selected from a maytansine, auristatin, calicheamicin, or derivative thereof. 13. The isolated bi-specific antigen binding construct of claim 9, wherein the drug is a maytansine selected from DM1 and DM4. 14. The isolated bi-specific antigen binding construct of claim 13, wherein the drug is conjugated to the isolated bi-specific antigen binding construct with an SMCC linker (DM1), or an SPDB linker (DM4). 15. A pharmaceutical composition comprising the isolated bi-specific antigen binding construct of claim 1 and a pharmaceutical carrier. 16. The pharmaceutical composition of claim 15, wherein the carrier comprises a buffer, an antioxidant, a low molecular weight molecule, a drug, a protein, an amino acid, a carbohydrate, a lipid, a chelating agent, a stabilizer, or an excipient. 17. A method of inhibiting growth of a cancer cell expressing HER2 and HER3, or of inducing antibody-dependent cellular cytotoxicity (ADCC) in a cancer cell, or of inhibiting dimerization of HER2 and HER3 in a cancer cell, comprising contacting the cancer cell with an effective amount of the isolated bi-specific antigen binding construct of claim 1. 18. A method of inhibiting growth and/or proliferation of one or more tumor cells in a mammal, or a method of treating a tumor in a mammal, comprising administering an effective amount of the isolated bispecific antigen-binding construct of claim 1 to the mammal, wherein a) the one or more tumor cells express HER2 and HER3; b) the tumor is characterized by HER2 and/or HER3 overexpression; c) the tumor expresses low levels of HER2 and/or HER3; or d) the tumor co-expresses HER2 and HER3. 19. The isolated bi-specific antigen-binding construct of claim 1, comprising a polypeptide having the sequence set forth in SEQ ID NO:6, a polypeptide having the sequence set forth in SEQ ID NO:2, and a polypeptide having the sequence set forth in SEQ ID NO:16. 20. The isolated bi-specific antigen-binding construct of claim 19, conjugated to a detectable label or drug.

Details for Patent 10,239,951

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Genentech, Inc.	HERCEPTIN	trastuzumab	For Injection	103792	09/25/1998		2033-05-08
Genentech, Inc.	HERCEPTIN	trastuzumab	For Injection	103792	02/10/2017		2033-05-08
Genentech, Inc.	HERCEPTIN HYLECTA	trastuzumab and hyaluronidase-oysk	Injection	761106	02/28/2019		2033-05-08