WO2009070753A2

WO2009070753A2 - Bivalent single chain fv antibody compositions that specifically bind to integrin receptor on a metastatic cell in a mammalian subject

Info

Publication number: WO2009070753A2
Application number: PCT/US2008/085008
Authority: WO
Inventors: Kim D. Janda; Gunnar Kaufmann
Original assignee: The Scripps Research Institute
Priority date: 2007-11-28
Filing date: 2008-11-26
Publication date: 2009-06-04
Also published as: WO2009070753A3

Abstract

Isolated bivalent single chain Fv antibody compositions and pharmaceutical compositions thereof are provided having affinity for a tumor cell target wherein the tumor cell has a metastatic phenotype. The antibody compositions are provided that specifically bind to an αvβ3 integrin receptor on the metastatic cell.

Description

BIVALENT SINGLE CHAIN FV ANTIBODY COMPOSITIONS THAT SPECIFICALLY

BIND TO INTEGRIN RECEPTOR ON A METASTATIC CELL

IN A MAMMALIAN SUBJECT

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 61/000,325, filed on November 28, 2007; which is herein incorporated by reference, in its entirety, for all purposes.

FIELD

[0002] The invention generally relates to isolated bivalent single chain Fv antibody and pharmaceutical compositions having affinity for an αvβ3 integrin receptor on a tumor cell wherein the tumor cell has a metastatic phenotype. The invention further relates to antibody compositions that specifically bind to a activated αvβ3 integrin receptor on the metastatic cell.

BACKGROUND

[0003] Antibody fragments are recognized as promising vehicles for delivery of imaging and therapeutic agents to tumor sites in vivo. The serum persistence of IgGl and fragments with intact Fc region is controlled by the protective neonatal Fc receptor (FcRn) receptor. To modulate the half-life of engineered antibodies, the Fc-FcRn binding site of chimeric antibodies have been mutated to produce a single-chain Fv-Fc format.

[0004] An example of a domain-deleted recombinant antibody fragment is the single- chain Fv-Fc (scFv-Fc), where the scFv (VH-linker-VL) fragment was joined to the intact Fc region (C _H2 and C_H3 domains) of human IgGl via a hinge region. The anti-carcinoembryonic antigen (CEA) scFv-Fc is one example. This antibody fragment behaves similarly to intact antibodies specifically regarding serum persistence and tumor uptake. The scFv-Fc antibody fragment includes an intact Fc region, which is crucial for prolonging the half-life of antibodies and antibody fragments. Specific interactions between antibody Fc domain amino acid residues and the protective neonatal Fc receptor (FcRn; Brambell receptor) essentially divert IgGs from the lysosomal degradative pathway compared with other serum proteins. Kenanova et al., Cancer Res. 65: 622-631, 2005.

[0005] To determine whether cancer patients have ever made antibodies with disease- fighting potential, studies have screened combinatorial antibody libraries from cancer patients for immunoglobulins that can identify metastatic tumor cells. The strategy has yielded human antibodies specific for the activated conformation of the adhesion receptor integrin αvβ3 that is associated with a metastatic phenotype. Two of these antibodies were shown to contain the Arg- GIy- Asp (RGD) integrin recognition motif of the natural ligand within the third complementarity-determining region of the heavy chain. These antibodies interfered with lung colonization by human breast cancer cells in a mouse model and inhibited existing metastatic disease. The data imply that, at least at some time, these antibodies were part of a patient's surveillance system against metastatic cells, targeting the activated conformer of integrin αvβ3 and disrupting its functions. The possible ligand-mimetic nature of these antibodies, combined with specificity for a single receptor, provides the potential for a therapeutic reagent for treatment of metastatic cancer. Felding-Habermann, et al., Proc Natl Acad Sci USA, 101: 17210-17215, 2004; U.S. Patent No. 7,271,245.

[0006] No therapy is known today that prevents cancer from becoming systemic, and there is little understanding of even how to design and test such drugs. Metastases ultimately are responsible for much of the suffering and mortality from metastatic cancer, for example, breast cancer. A need exists to identify and target molecular and functional markers that identify metastatic cancer cells and to generate reagents for specific inhibition of metastatic cancer cells and improved therapeutic compositions useful in treatment of metastatic disease.

SUMMARY

[0007] The invention generally relates to isolated bivalent single chain Fv antibody and pharmaceutical compositions having affinity for an αvβ3 integrin receptor on a tumor cell wherein the tumor cell has a metastatic phenotype. The invention further relates to bivalent single chain Fv antibody compositions that specifically bind to a activated αvβ3 integrin receptor on the metastatic cell. [0008] An isolated scFv-Fc fusion antibody is provided which specifically binds to an activated αvβ3 integrin receptor which is differentially produced on a cell in a metastatic state compared to a similar, non-metastatic cell, the antibody comprising an amino acid sequence of SEQ ID NO: 1 and an Fc constant region covalently bound to the carboxy terminus of SEQ ID NO: 1. In one aspect, the Fc constant region is an IgGl , IgG2, IgG3, or IgG4 constant region. The metastatic cell can target to a tissue selected from breast, brain, lung, liver, or bone. In a detailed aspect, the antibody is a ligand mimetic. In a further aspect, the scFv-Fc fusion antibody comprises an amino acid sequence of SEQ ID NO: 4.

[0009] A pharmaceutical composition is provided which comprises an isolated scFv-Fc fusion antibody which specifically binds to an activated αvβ3 integrin receptor which is differentially produced on a cell in a metastatic state compared to a similar, non-metastatic cell, the antibody comprising an amino acid sequence of SEQ ID NO:1 and an Fc constant region covalently bound to the carboxy terminus of SEQ ID NO: 1. In a further aspect, the scFv-Fc fusion antibody comprises an amino acid sequence of SEQ ID NO: 4.

[0010] An isolated polynucleotide encoding an scFv-Fc fusion antibody is provided wherein the polynucleotide comprising a nucleotide sequence that has at least 90% identity to SEQ ID NO: 3. An isolated polypeptide is provided which comprises an amino acid sequence that has at least 90% sequence identity to SEQ ID NO: 4, wherein the polypeptide specifically binds to an activated αvβ3 integrin receptor which is differentially produced on a cell in a metastatic state compared to a similar, non-metastatic cell. A vector is provided which comprises the polynucleotide as above. An expression vector is provided which comprises the polynucleotide as above in which the nucleotide sequence of the polynucleotide is operatively linked with a regulatory sequence that controls expression of the polynucleotide in a host cell. A host cell is provided which comprises the expression vector, or progeny of the cell.

[0011] An isolated scFv-Fc fusion antibody is provided which specifically binds to an activated αvβ3 integrin receptor which is differentially produced on a cell in a metastatic state compared to a similar, non-metastatic cell, the antibody comprising an amino acid sequence of SEQ ID NO:2 and an Fc constant region covalently bound to the carboxy terminus of SEQ ID NO:2. In one aspect, the Fc constant region is an IgGl, IgG2, IgG3, or IgG4 constant region. The metastatic cell can target to a tissue selected from breast, brain, lung, liver, or bone. In a detailed aspect, the antibody is a ligand mimetic. In a further aspect, the scFv-Fc fusion antibody comprises an amino acid sequence of SEQ ID NO:6.

[0012] A pharmaceutical composition is provided which comprises an isolated scFv-Fc fusion antibody which specifically binds to an activated αvβ3 integrin receptor which is differentially produced on a cell in a metastatic state compared to a similar, non-metastatic cell, the antibody comprising an amino acid sequence of SEQ ID NO:2 and an Fc constant region covalently bound to the carboxy terminus of SEQ ID NO:2. In a further aspect, the scFv-Fc fusion antibody comprises an amino acid sequence of SEQ ID NO:6.

[0013] An isolated polynucleotide encoding an scFv-Fc fusion antibody is provided wherein the polynucleotide comprising a nucleotide sequence that has at least 90% identity to SEQ ID NO:5. An isolated polypeptide is provided which comprises an amino acid sequence that has at least 90% sequence identity to SEQ ID NO: 6, wherein the polypeptide specifically binds to an activated αvβ3 integrin receptor which is differentially produced on a cell in a metastatic state compared to a similar, non-metastatic cell. A vector is provided which comprises the polynucleotide as above. An expression vector is provided which comprises the polynucleotide as above in which the nucleotide sequence of the polynucleotide is operatively linked with a regulatory sequence that controls expression of the polynucleotide in a host cell. A host cell is provided which comprises the expression vector, or progeny of the cell.

[0014] A method for treating cancer in a mammal is provided which comprises administering to the mammal an isolated scFv-Fc fusion antibody which specifically binds to an activated αvβ3 integrin receptor which is differentially produced on a cell in a metastatic state as compared to a non-metastatic cell, the antibody comprising an amino acid sequence of SEQ ID NO: 1 and an Fc constant region covalently bound to the carboxy terminus of SEQ ID NO: 1. In one aspect, the scFv-Fc fusion antibody comprises an amino acid sequence of SEQ ID NO: 4.

[0015] A method for treating cancer in a mammal is provided which comprises administering to the mammal an isolated scFv-Fc fusion antibody which specifically binds to an activated αvβ3 integrin receptor which is differentially produced on a cell in a metastatic state as compared to a non-metastatic cell, the antibody comprising an amino acid sequence of SEQ ID NO:2 and an Fc constant region covalently bound to the carboxy terminus of SEQ ID NO:2. In one aspect, the scFv-Fc fusion antibody comprises an amino acid sequence of SEQ ID NO:6.

[0016] The cancer can include, but is not limited to, solid tumor, hematological malignancy, leukemia, colorectal cancer, benign or malignant breast cancer, uterine cancer, uterine leiomyomas, ovarian cancer, endometrial cancer, polycystic ovary syndrome, endometrial polyps, prostate cancer, prostatic hypertrophy, pituitary cancer, adenomyosis, adenocarcinomas, meningioma, melanoma, bone cancer, multiple myeloma, CNS cancer, glioma, or astroblastoma. In a detailed aspect, the cancer is breast cancer metastasis in the mammal. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figures IA, IB, and 1C show construction of pSecFc-Ab5 expression vector. (A) original pSecTag2a, (B) pSecTag2a with second Sβl site and Fc domain (=pSecFc), (C) pSecFc containing scFv5 (⁼pSecFc-Ab5).

[0018] Figure 2 shows whole cell ELISA analyzing the binding of scFv5- and Fab5- phage to M21 cells.

[0019] Figure 3 shows flow cytometric analysis of scFv5 and Fab5 to M21 cancer cells in the presence or absence of bivalent metal cations.

[0020] Figure 4 shows whole cell ELISA analyzing the binding of scFv5 and IgG5 (Ab5) to M21 cells.

[0021] Figure 5 shows Western blot analysis of scFv5-Fc expression.

[0022] Figure 6 shows SDS-PAGE analysis of purified scFv5-Fc protein under reducing conditions

[0023] Figure 7 shows comparison of the binding of scFv5 and scFv5-Fc to SJSA-I cancer cell using flow cytometric analysis.

[0024] Figure 8 shows flow cytometric analysis of the metal-dependent binding of scFv5-Fc to SJSA-I cancer cells.

[0025] Figure 9 shows an analysis of the abilities of scFv5, Mut5, IgG5, and control IgG to bind to BCM2 cancer cells.

[0026] Figure 10 shows an analysis of the ability of scFv5-Fc to bind to BCM2 and SJSA-I cancer cells.

[0027] Figure 11 shows the scFv5 amino acid sequence (SEQ ID NO:1) and the scFvl amino acid sequence (SEQ ID NO:2).

[0028] Figure 12 shows the scFv5-Fc nucleic acid sequence (SEQ ID NO:3) and the scFv5-Fc amino acid sequence (SEQ ID NO:4).

[0029] Figure 13 shows the scFvl-Fc nucleic acid sequence (SEQ ID NO:5) and the scFvl-Fc amino acid sequence (SEQ ID NO: 6).

[0030] Figures 14A, 14B, 14C, 14D, and 14E show the scFv5-Fc/ variant IgGl having nucleic acid sequence (SEQ ID NO:7, 9, 11, 13, 15) and the scFv5-Fc/ variant IgGl amino acid sequence (SEQ ID NO:8, 10, 12, 14, 16).

[0031] Figures 15A, 15B, 15C, 15D, and 15E show the scFvl-Fc/ variant IgGl having nucleic acid sequence (SEQ ID NO:17, 19, 21, 23, 25) and the scFvl-Fc/ variant IgGl amino acid sequence (SEQ ID NO: 18, 20, 22, 24, 26). [0032] Figures 16A, 16B, 16C, and 16D show the scFv5-Fc/IgGl-4 variants having nucleic acid sequence (SEQ ID NO:27, 29, 31, 33) and the scFv5-Fc/IgGl-4 variant amino acid sequence (SEQ ID NO: 28, 30, 32, 34).

[0033] Figures 17A, 17B, 17C, and 17D show the scFvl-Fc/IgGl-4 variants having nucleic acid sequence (SEQ ID NO:35, 37, 39, 41) and the scFvl-Fc/IgGl-4 variant amino acid sequence (SEQ ID NO:36, 38, 40, 42).

[0034] Figures 18A and 18B show the scFvl-Fc/ variant IgGl having nucleic acid sequence (SEQ ID NO: 43, 45) and the scFvl-Fc/IgGl amino acid sequence (SEQ ID NO: 44, 46).

[0035] Figures 19A and 19B shows the scFv5-Fc/ variant IgGl having nucleic acid sequence (SEQ ID NO: 47, 49) and the scFv5-Fc/ variant IgGl amino acid sequence (SEQ ID NO: 48, 50).

DETAILED DESCRIPTION

[0036] The invention is generally related to bivalent single chain Fv antibody compositions and pharmaceutical compositions having affinity for a tumor cell target which is a tumor cell expressing a metastatic phenotype. The tumor cell expressing the metastatic phenotype can be a cell line expressing an activated cell surface receptor, for example, an activated integrin receptor or an activated αvβ3 integrin receptor. The invention further relates to antibody compositions and pharmaceutical compositions thereof that specifically binds to a cell surface receptor on a metastatic cell. The antibody composition specifically binds to a activated cell surface receptor on a metastatic cell, for example, an activated integrin receptor or an activated αvβ3 integrin receptor. The invention further relates to methods for treating cancer in a mammal by treatment with a cancer therapeutic comprising the step of administering to the mammal a therapeutic amount of said pharmaceutical composition of the antibody composition.

[0037] The preparation and use of bivalent single chain Fv-Fc antibody provide improved pharmacokinetic properties which utilize single chain Fv antibodies covalently bound to an Fc constant region. In one aspect, the bivalent Fv antibody is a scFv5-Fc protein, which is a fusion protein consisting of anti-αvβ3 integrin receptor single-chain antibody, scFv5 (BcI 5; Felding-Habermann, et al, Proc Natl Acad Sci USA, 101: 17210-17215, 2004), and a human antibody constant region, i.e., C_H2-C_H3. In a detailed aspect, an isolated scFv-Fc fusion antibody is provided which specifically binds to an activated αvβ3 integrin receptor which is differentially produced on a cell in a metastatic state compared to a similar, non-metastatic cell, said antibody comprising an amino acid sequence of SEQ ID NO: 1 and an Fc constant region covalently bound to the carboxy terminus of SEQ ID NO: 1. In a detailed aspect, the scFv-Fc fusion antibody comprises an amino acid sequence of SEQ ID NO: 4.

[0038] The bivalent scFv-Fc antibody provides improved pharmacokinetic properties. The isolated bivalent scFv-Fc antibody, for example, scFv5-Fc, resulted in a fully functional binding antibody. By contrast, conversion of the scFv5 antibody to a Fab antibody, Fab5, or an IgG antibody, IgG5, resulted in a total loss of binding ability and rendered these particular Fab or IgG antibodies biologically inactive.

[0039] In a further aspect, the bivalent Fv antibody is a scFvl-Fc protein, which is a fusion protein consisting of anti-αvβ3 integrin receptor single-chain antibody, scFvl (Bcl2; Felding-Habermann, et al, Proc Natl Acad Sci USA, 101: 17210-17215, 2004), and a human antibody constant region. In a detailed aspect, an isolated scFv-Fc fusion antibody is provided which specifically binds to an activated αvβ3 integrin receptor which is differentially produced on a cell in a metastatic state compared to a similar, non-metastatic cell, said antibody comprising an amino acid sequence of SEQ ID NO: 2 and an Fc constant region covalently bound to the carboxy terminus of SEQ ID NO:2. In a detailed aspect, the scFv-Fc fusion antibody comprises an amino acid sequence of SEQ ID NO: 6.

[0040] Due to the presence of the antibody constant region, the expressed scFv5-Fc protein or the scFvl-Fc protein will dimerize via formation of intermolecular disulfide bonds between the two monomers, thus, resulting in a bivalent recombinant antibody molecule with a molecular weight of 100 kD (monomer: 50 kD).

[0041] scFv antibodies generally do not possess significant in vivo half- life due to their size (approx. 25 kD) and absence of an antibody constant region which also causes a lack of any biological effector function, such as complement fixation, complement-dependent cytotoxicity (CDC), and antibody-dependent cellular cytotoxicity (ADCC). To address these problems, most scFv antibodies are converted into Fab antibody fragments or whole IgG antibodies using antibody engineering methodology. However, upon conversion of scFv5 into Fab5 (V_H derived from scFv5 fused to human CHI and VL derived from scFv5 fused to human Cka_PPa) or IgG5 (VH derived from scFv5 fused to human C_H1-C_H2-C_H3 and V_L derived from scFv5 fused to human Ckappa), subsequent expression and analysis a total loss of binding ability was detected, rendering these particular constructs biologically inactive.

[0042] Notably, the fusion of human antibody constant C_H2-C_H3 to scFv5 resulted in a fully functional binding antibody. In addition, the bivalent binding nature of the new antibody construct and potential avidity effects led to improved binding. scFv5-Fc fusion antibody and pharmaceutical compositions thereof can be useful as a therapeutic and diagnostic tool in similar manner to the scFv5 (Bc- 15) antibody. The scFv5-Fc fusion antibody provides superior pharmacokinetic and pharmacodynamic parameters as well as improved binding ability as compared to its parental scFv5.

[0043] Due to the presence of the human antibody constant region and the resulting dimerization, the scFv5-Fc fusion protein now has a molecular weight of 100 kD which dramatically improves its pharmacokinetic and pharmacodynamic parameters as it is no longer subject to renal clearance as well as it will undergo all physiological antibody recycling mechanism. Secondly, the presence of the constant region bestows new biological activities upon the scFv5-Fc fusion protein, such as complement-dependent cytotoxicity (CDC) and antibody- dependent cell-mediated cytotoxicity (ADCC). Furthermore, the bivalent format has led to an improvement of the binding ability of scFv-Fc compared to its parental scFv5 antibody as determined by flow cytometric analysis. Via the protein engineering of the Fc constant region, one will be able to tune the biological activities listed above, e.g., the biological half- life can be increased or decreased through point mutations in the Fc part as these will modify the affinity of the scFv5-Fc protein for certain Fc receptors that play an important role in physiological antibody recycling. Similar modulation of Fc receptor affinity will increase or decrease the biological effector functions of scFv5-Fc resulting in more or less potent activation of CDC or ADCC.

[0044] The present invention provides a method for treating cancer in a mammalian subject by administering to the mammal an isolated scFv-Fc fusion antibody which specifically binds to an activated αvβ3 integrin receptor which is differentially produced on a cell in a metastatic state as compared to a non-metastatic cell. Inhibition of metastatic cell proliferation can be accomplished by exposing tumor cells to an isolated scFv-Fc fusion antibody that binds to an activated αvβ3 integrin receptor on the tumor cell surface. In one aspect, the isolated scFv-Fc fusion antibody is scFv5-Fc fusion antibody or an scFvl-Fc fusion antibody. Inhibition of metastatic cell proliferation by binding of the scFv-Fc fusion antibody to the activated αvβ3 integrin receptor can lead to a decrease in cell growth and can also render the metastatic tumor cells more susceptible to therapeutic agents. Alternatively, the scFv-Fc fusion antibody binding to the activated αvβ3 integrin receptor, can inhibit the activation of the receptor and can lead to apoptosis of metastatic tumor cells.

[0045] Therefore, the invention provides a method of treatment of mammalian subjects suffering from metastatic cancer by administering to the mammal an anti-αvβ3 integrin receptor scFv-Fc antibody to inhibit tumor cell metastasis. Preferably the invention provides for a treatment of mammals suffering from metastatic cancer, for example, breast cancer. In addition, the treatment comprises administering to the mammal an anti-αvβ3 integrin receptor scFv-Fc recombinant antibody in combination with one or more therapeutic agents, such as tamoxifen which are effective in reducing the growth of metastatic tumors.

[0046] In one aspect, the anti-αvβ3 integrin receptor scFv-Fc antibody is a single chain recombinant antibody covalently bound to an Fc region, e.g., C_H2-C_H3 region, such as an scFv5- Fc antibody or an scFvl-Fc antibody. The single-chain antibodies, scFv-Fc, are advantageous because of the relative ease in their expression, purification and manipulation. The expression of such antibodies in expression systems makes them more susceptible to large scale production and purification. In addition, manipulation of such single chain antibodies may consist of altering such antibodies to covalently attach other therapeutic agents. Such agents can, for example, include toxins, enzymes, or radionucleotides. The recombinant single chain antibody conjugated with such agents can block activated αvβ3 integrin receptor induced tumor cell metastasis and target such agents to the tumor cells which have been made more susceptible to apoptosis by the inhibition of activated αvβ3 integrin receptor.

[0047] The single chain antibody, scFv-Fc, comprises at least an Fv domain capable of blocking activated αvβ3 integrin receptor interaction with integrin. The anti-αvβ3 integrin receptor scFv5 or scFvl comprises both the antigen binding region of a light chain variable domain, V_L, and the antigen binding region of a heavy chain variable domain, V_H, coupled by a short linker peptide. In one embodiment, the V_L domain and the V_H domain are derived from the scFv5 or scFvl antibody which binds to an activated αvβ3 integrin receptor. The scFv5-Fc or scFvl-Fc can be purified using a Protein A or Protein G affinity column, without an artificial affinity tag. Alternatively, the scFv5-Fc or scFvl-Fc may be tagged with a short peptide such as the FLAG epitope to facilitate purification of the soluble scFv5-Fc or scFvl-Fc antibody from the medium of the expression system. The DNA coding for the V_L and V_H domains are obtainable by sequencing the domains from a parental antibody, in one aspect, the parental antibody being scFv5 or scFvl . A recombinant DNA then can be constructed comprising, in order, coding sequences for the N-terminal signal peptide, the antigen binding region of the V_L domain, a linker peptide, the antigen binding region of the V_H domain and a C-terminal tag peptide for purification and identification. The genetically engineered antibody can be expressed in myeloma or bacterial cell expression systems. The monovalent recombinant single chain antibody anti-αvβ3 integrin receptor scFv antibody or an scFv antibody, scFv5-Fc or scFvl-Fc, can be purified from the medium of the expression system by conventional protein purification methods, such as, for example, affinity chromatography. [0048] The linker peptide which covalently binds the scFv to the Fc polypeptides is chosen based upon known structural and conformational information of peptide segments and is selected so that it will not interfere with the tertiary structure of the single chain antibody and its uses. Typically, a linker of between about 6 and 50 amino acids is preferred for ease and economics of preparation.

[0049] In one aspect, the soluble anti-αvβ3 integrin receptor scFv5 or scFvl is a chimeric antibody which further comprise an Fc domain. In this embodiment, the recombinant DNA will comprise the coding sequence of scFv5 or scFvl minus the C-terminal tag peptide, coupled to a coding sequence for an Fc domain. Desirably, the Fc domain comprises the C_R2 and C_H3 regions of an antibody heavy chain constant domain. The recombinant DNA can be expressed in a mammalian, e.g. , Chinese hamster ovary (CHO) cells, or bacterial expression system in accordance with conventional techniques and the single-chain antibody scFv5-Fc or scFvl-Fc can be purified using conventional protein purification methods. The scFv5-Fc or scFvl-Fc exists preferably in its divalent form. The scFv5-Fc or scFvl-Fc comprise a fully human sequence of the anti-αvβ3 integrin receptor scFv by using a coding sequence of a human Fc domain when constructing the recombinant DNA. The single-chain antibodies, e.g., scFv5-Fc or scFvl-Fc subsequently can be modified, if desired, and attached to other therapeutic agents.

[0050] To treat mammals suffering from metastatic cancer, for example, metastatic breast cancer, the recombinant single-chain antibodies or bivalent antibodies, e.g., scFv5-Fc or scFvl-Fc, can be administered in a pharmaceutically acceptable composition as the sole therapeutic or in combination with one or more other therapeutic agents, such as tamoxifen, which are effective in reducing metastatic tumor cell growth. The tamoxifen or other therapeutic agent can be administered in accordance with conventional therapeutic methods, such as parenteral or subcutaneous administration. Administration of the recombinant single chain antibodies can be used as a method of inhibiting tumor cell growth in vivo or to induce susceptibility of the tumor cells to therapeutic agents

[0051] It is to be understood that this invention is not limited to particular methods, reagents, compounds compositions or biological systems, which can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to be limiting. As used in this specification and the appended claims, the singular forms "a", "an" and "the" include plural referents unless the content clearly dictates otherwise. Thus, for example, reference to "a cell" includes a combination of two or more cells, and the like. [0052] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although any methods and materials similar or equivalent to those described herein can be used in the practice for testing of the present invention, the preferred materials and methods are described herein. In describing and claiming the present invention, the following terminology will be used.

[0053] An intact "antibody" comprises at least two heavy (H) chains and two light (L) chains inter-connected by disulfide bonds. Each heavy chain is comprised of a heavy chain variable region (abbreviated herein as HCVR or V_H) and a heavy chain constant region. The heavy chain constant region is comprised of three domains, C_HI , C_H2 and C_H3. Each light chain is comprised of a light chain variable region (abbreviated herein as LCVR or V_L) and a light chain constant region. The light chain constant region is comprised of one domain, C_L. The V_H and V_L regions can be further subdivided into regions of hypervariability, termed complementarity determining regions (CDR), interspersed with regions that are more conserved, termed framework regions (FR). Each V_H and V_L is composed of three CDRs and four FRs, arranged from amino-terminus to carboxyl-terminus in the following order: FRl, CDRl, FR2, CDR2, FR3, CDR3, FR4. The variable regions of the heavy and light chains contain a binding domain that interacts with an antigen. The constant regions of the antibodies can mediate the binding of the immunoglobulin to host tissues or factors, including various cells of the immune system (e.g., effector cells) and the first component (CIq) of the classical complement system. The term antibody includes antigen-binding portions of an intact antibody that retain capacity to bind activated integrin receptor. Examples of binding include (i) a Fab fragment, a monovalent fragment consisting of the V_L, V_H, C_L and C_HI domains; (ii) a F(ab')₂ fragment, a bivalent fragment comprising two Fab fragments linked by a disulfide bridge at the hinge region; (iii) a Fd fragment consisting of the V_H and C_HI domains; (iv) a Fv fragment consisting of the V_L and V_H domains of a single arm of an antibody, (v) a dAb fragment (Ward et al, Nature 341: 544- 546, 1989), which consists of a V_H domain; and (vi) an isolated complementarity determining region (CDR).

[0054] "Single chain antibodies" or "single chain Fv (scFv)" refers to an antibody fusion molecule of the two domains of the Fv fragment, V_L and V_H- Although the two domains of the Fv fragment, V_L and V_H, are coded for by separate genes, they can be joined, using recombinant methods, by a synthetic linker that enables them to be made as a single protein chain in which the V_L and V_H regions pair to form monovalent molecules (known as single chain Fv (scFv); see, e.g., Bird et al, Science 242: 423-426, 1988; and Huston et al, Proc. Natl Acad. Sci. USA, 85: 5879-5883, 1988). Such single chain antibodies are included by reference to the term "antibody" fragments can be prepared by recombinant techniques or enzymatic or chemical cleavage of intact antibodies.

[0055] "Fc polypeptide" or "Fc domain" refers to native and mutein forms of polypeptides derived from the Fc region of an antibody. Truncated forms of such polypeptides containing the hinge region that promotes dimerization are also included.

[0056] One suitable Fc polypeptide, described in PCT application WO 93/10151 , is a single chain polypeptide extending from the N-terminal hinge region to the native C-terminus of the Fc region of a human IgGl antibody. Another useful Fc polypeptide is the Fc mutein described in U.S. Pat. No. 5,457,035 and by Baum et al, EMBOJ. 13:3992, 1994. The amino acid sequence of this mutein is identical to that of the native Fc sequence presented in WO 93/10151, except that amino acid 19 has been changed from Leu to Ala, amino acid 20 has been changed from Leu to GIu, and amino acid 22 has been changed from GIy to Ala. The mutein exhibits reduced affinity for Fc receptors. Fusion polypeptides comprising Fc moieties, and multimers formed therefrom, offer an advantage of facile purification by affinity chromatography over Protein A or Protein G columns, and Fc fusion polypeptides may provide a longer in vivo half life, which is useful in therapeutic applications, than unmodified polypeptides.

[0057] The procedure for purifying expressed soluble scFv5-Fc or scFvl-Fc polypeptides will vary according to the host system employed, and whether or not the recombinant polypeptide is secreted. Soluble scFv5-Fc or scFvl-Fc polypeptides may be purified using methods known in the art, including one or more concentration, salting-out, ion exchange, hydrophobic interaction, affinity purification, HPLC, or size exclusion chromatography steps. Fusion polypeptides comprising Fc moieties (and multimers formed therefrom) offer the advantage of facile purification by affinity chromatography over Protein A or Protein G columns.

[0058] "Effector functions of an Fc region" refer to those biological activities attributable to the Fc region (a native sequence Fc region or amino acid sequence variant Fc region) of an antibody. Examples of antibody effector functions include, but are not limited to, CIq binding; complement dependent cytotoxicity; Fc receptor binding; antibody-dependent cell- mediated cytotoxicity (ADCC); phagocytosis; down regulation of cell surface receptors (e.g., B cell receptor; BCR).

[0059] For example, the scFv5 or scFvl antibodies may be fused or conjugated to an antibody Fc region, or portion thereof. The Fc region fused to a single chain Fv antibody of the present invention may comprise the constant region, hinge region, C_HI domain, C_H2 domain, and C_H3 domain or any combination of whole domains or portions thereof. The single chain Fv antibodies may also be fused or conjugated to the Fc regions to form multimers. For example, Fc regions fused to the scFv5 or scFvl can form dimers through disulfide bonding between the Fc portions. Higher multimeric forms can be made by fusing the polypeptides to portions of IgA and IgM. Methods for fusing or conjugating the single chain Fv antibodies of the present invention to antibody portions are known in the art. See, e.g., U.S. Pat. Nos. 5,336,603; 5,622,929; 5,359,046; 5,349,053; 5,447,851; 5,112,946; EP 307,434; EP 367,166; PCT publications WO 96/04388; WO 91/06570; Ashkenazi et al, Proc. Natl. Acad. Sci. USA 88: 10535-10539 (1991); Zheng et al., J. Immunol. 154: 5590-5600, 1995; and ViI et al., Proc. Natl. Acad. Sci. USA 89: 11337-11341, 1992, references incorporated by reference in their entireties.

[0060] Moreover, scFv-Fc antibody compositions toαvβ3 integrin receptors, including fragments, and specifically epitopes, can be combined with parts of the constant domain of immunoglobulins (IgG), resulting in chimeric polypeptides. These fusion proteins facilitate purification and show an increased half-life in vivo. One reported example describes chimeric proteins consisting of the first two domains of the human CD4-polypeptide and various domains of the constant regions of the heavy or light chains of mammalian immunoglobulins. EPA 394,827; Traunecker et al, Nature, 331: 84-86, 1988. Fusion proteins having disulfide-linked dimeric structures (due to the IgG) can also be more efficient in binding and neutralizing other molecules, than the monomeric secreted protein or protein fragment alone. Fountoulakis et al, J. Biochem. 270: 3958-3964, 1995.

[0061] Similarly, EP-A-O 464 533 discloses fusion proteins comprising various portions of constant region of immunoglobulin molecules together with another human protein or part thereof. In many cases, the Fc part in a fusion protein is beneficial in therapy and diagnosis, and thus can result in, for example, improved pharmacokinetic properties. (EP-A 0232 262.) Alternatively, deleting the Fc part after the fusion protein has been expressed, detected, and purified, would be desired. For example, the Fc portion may hinder therapy and diagnosis if the fusion protein is used as an antigen for immunizations. In drug discovery, for example, human proteins, such as hIL-5, have been fused with Fc portions for the purpose of high-throughput screening assays to identify antagonists of hIL-5. Bennett et al, J. Molecular Recognition 8: 52- 58, 1995; K. Johanson et al, J. Biol. Chem., 270: 9459-9471 1995.

[0062] Moreover, the polypeptides can be fused to marker sequences, such as a peptide which facilitates purification of the fused polypeptide. In preferred embodiments, the marker amino acid sequence is a hexa-histidine peptide, such as the tag provided in a pQE vector (QIAGEN, Inc., 9259 Eton Avenue, Chatsworth, Calif., 91311), among others, many of which are commercially available. As described in Gentz et al., Proc. Natl. Acad. Sci. USA 86: 821- 824, 1989, for instance, hexa-histidine provides for convenient purification of the fusion protein. Another peptide tag useful for purification, the "HA" tag, corresponds to an epitope derived from the influenza hemagglutinin protein. Wilson et al, Cell 37: 767, 1984.

[0063] Thus, any of these above fusions can be engineered using the polynucleotides or the polypeptides of the present invention.

[0064] "Human sequence antibody" includes antibodies having variable and constant regions (if present) derived from human germline immunoglobulin sequences. The human sequence antibodies of the invention can include amino acid residues not encoded by human germline immunoglobulin sequences {e.g., mutations introduced by random or site-specific mutagenesis in vitro or by somatic mutation in vivo). Such antibodies can be generated in non- human transgenic animals, e.g., as described in PCT Publication Nos. WO 01/14424 and WO 00/37504. However, the term "human sequence antibody", as used herein, is not intended to include antibodies in which CDR sequences derived from the germline of another mammalian species, such as a mouse, have been grafted onto human framework sequences {e.g. , humanized antibodies).

[0065] Also, recombinant immunoglobulins may be produced. See, Cabilly, U.S. Pat. No. 4,816,567, incorporated herein by reference in its entirety and for all purposes; and Queen et al., Proc. Na? I Acad. Sci. USA 86: 10029-10033, 1989.

[0066] "Monoclonal antibody" refer to a preparation of antibody molecules of single molecular composition. A monoclonal antibody composition displays a single binding specificity and affinity for a particular epitope. Accordingly, the term "human monoclonal antibody" refers to antibodies displaying a single binding specificity which have variable and constant regions (if present) derived from human germline immunoglobulin sequences. In one embodiment, the human monoclonal antibodies are produced by a hybridoma which includes a B cell obtained from a transgenic non-human animal, e.g. , a transgenic mouse, having a genome comprising a human heavy chain transgene and a light chain transgene fused to an immortalized cell.

[0067] "Polyclonal antibody" refers to a preparation of more than 1 (two or more) different antibodies to a cell surface receptor, e.g., human activated integrin receptor. Such a preparation includes antibodies binding to a range of different epitopes. Antibodies to activated integrin receptor can bind to an epitope on human activated integrin receptor so as to inhibit activated integrin receptor from interacting with a counterreceptor or co-receptor. These and other antibodies suitable for use in the present invention can be prepared according to methods that are well known in the art and/or are described in the references cited here. In preferred embodiments, anti-activated integrin receptor antibodies used in the invention are "human antibodies"— e.g.,. antibodies isolated from a human—or they are "human sequence antibodies" (defined supra).

[0068] "Immune cell response" refers to the response of immune system cells to external or internal stimuli (e.g., antigen, cell surface receptors, activated integrin receptors, cytokines, chemokines, and other cells) producing biochemical changes in the immune cells that result in immune cell migration, killing of target cells, phagocytosis, production of antibodies, other soluble effectors of the immune response, and the like.

[0069] "Immune response" refers to the concerted action of lymphocytes, antigen presenting cells, phagocytic cells, granulocytes, and soluble macromolecules produced by the above cells or the liver (including antibodies, cytokines, and complement) that results in selective damage to, destruction of, or elimination from the human body of cancerous cells, metastatic tumor cells, metastatic breast cancer cells, invading pathogens, cells or tissues infected with pathogens, or, in cases of autoimmunity or pathological inflammation, normal human cells or tissues.

[0070] "T lymphocyte response" and "T lymphocyte activity" are used here interchangeably to refer to the component of immune response dependent on T lymphocytes (e.g. , the proliferation and/or differentiation of T lymphocytes into helper, cytotoxic killer, or suppressor T lymphocytes, the provision of signals by helper T lymphocytes to B lymphocytes that cause or prevent antibody production, the killing of specific target cells by cytotoxic T lymphocytes, and the release of soluble factors such as cytokines that modulate the function of other immune cells).

[0071] Components of an immune response can be detected in vitro by various methods that are well known to those of ordinary skill in the art. For example, (1) cytotoxic T lymphocytes can be incubated with radioactive Iy labeled target cells and the lysis of these target cells detected by the release of radioactivity; (2) helper T lymphocytes can be incubated with antigens and antigen presenting cells and the synthesis and secretion of cytokines measured by standard methods (Windhagen et ah, Immunity, 2: 373-80, 1995); (3) antigen presenting cells can be incubated with whole protein antigen and the presentation of that antigen on MHC detected by either T lymphocyte activation assays or biophysical methods (Harding et al. , Proc. Natl. Acad. Sci., 86: 4230-4, 1989); (4) mast cells can be incubated with reagents that cross-link their Fc-epsilon receptors and histamine release measured by enzyme immunoassay (Siraganian et al, TIPS, 4: 432-437, 1983). [0072] Similarly, products of an immune response in either a model organism (e.g. , mouse) or a human patient can also be detected by various methods that are well known to those of ordinary skill in the art. For example, (1) the production of antibodies in response to vaccination can be readily detected by standard methods currently used in clinical laboratories, e.g., an ELISA; (2) the migration of immune cells to sites of inflammation can be detected by scratching the surface of skin and placing a sterile container to capture the migrating cells over scratch site (Peters et ah, Blood, 72: 1310-5, 1988); (3) the proliferation of peripheral blood mononuclear cells in response to mitogens or mixed lymphocyte reaction can be measured using H-thymidine; (4) the phagocytic capacity of granulocytes, macrophages, and other phagocytes in PBMCs can be measured by placing PMBCs in wells together with labeled particles (Peters et al, Blood, 72: 1310-5, 1988); and (5) the differentiation of immune system cells can be measured by labeling PBMCs with antibodies to CD molecules such as CD4 and CD8 and measuring the fraction of the PBMCs expressing these markers.

[0073] For convenience, immune responses are often described in the present invention as being either "primary" or "secondary" immune responses. A primary immune response, which is also described as a "protective" immune response, refers to an immune response produced in an individual as a result of some initial exposure (e.g. the initial "immunization") to a particular antigen, e.g., cell surface receptor, or activated integrin receptor. Such an immunization can occur, for example, as the result of some natural exposure to the antigen (for example, from initial infection by some pathogen that exhibits or presents the antigen) or from antigen presented by cancer cells of some tumor in the individual (for example, a metastatic breast cancer cell). Alternatively,, the immunization can occur as a result of vaccinating the individual with a vaccine containing the antigen. For example, the vaccine can be a cancer vaccine comprising one or more antigens from a cancer cell e.g., a metastatic breast cancer cell.

[0074] A primary immune response can become weakened or attenuated over time and can even disappear or at least become so attenuated that it cannot be detected. Accordingly, the present invention also relates to a "secondary" immune response, which is also described here as a "memory immune response." The term secondary immune response refers to an immune response elicited in an individual after a primary immune response has already been produced. Thus, a secondary or immune response can be elicited, e.g., to enhance an existing immune response that has become weakened or attenuated, or to recreate a previous immune response that has either disappeared or can no longer be detected. An agent that can be administrated to elicit a secondary immune response is after referred to as a "booster" since the agent can be said to "boost" the primary immune response. [0075] As an example, and not by way of limitation, a secondary immune response can be elicited by re-introducing to the individual an antigen that elicited the primary immune response (for example, by re-administrating a vaccine). However, a secondary immune response to an antigen can also be elicited by administrating other agents that cannot contain the actual antigen. For example, the present invention provides methods for potentiating a secondary immune response by administrating an antibody to activated integrin receptor to an individual. In such methods the actual antigen need not necessarily be administered with the antibody to activated integrin receptor and the composition containing the antibody need not necessarily contain the antigen. The secondary or memory immune response can be either a humoral (antibody) response or a cellular response. A secondary or memory humoral response occurs upon stimulation of memory B cells that were generated at the first presentation of the antigen. Delayed type hypersensitivity (DTH) reactions are a type of cellular secondary or memory immune response that are mediated by CD4⁺ cells. A first exposure to an antigen primes the immune system and additional exposure(s) results in a DTH.

[0076] "Immunologically cross-reactive" or "immunologically reactive" refers to an antigen which is specifically reactive with an antibody which was generated using the same ("immunologically reactive") or different ("immunologically cross-reactive") antigen. Generally, the antigen is activated integrin receptor, or more typically an αvβ3 integrin receptor or subsequence thereof.

[0077] "Immunologically reactive conditions" refers to conditions which allow an antibody, generated to a particular epitope of an antigen, to bind to that epitope to a detectably greater degree than the antibody binds to substantially all other epitopes, generally at least two times above background binding, preferably at least five times above background. Immunologically reactive conditions are dependent upon the format of the antibody binding reaction and typically are those utilized in immunoassay protocols. See, Harlow and Lane, Antibodies, A Laboratory Manual, Cold Spring Harbor Publications, New York, 1988 for a description of immunoassay formats and conditions.

[0078] "Cell surface receptor" refers to molecules and complexes of molecules capable of receiving a signal and the transmission of such a signal across the plasma membrane of a cell. An example of a "cell surface receptor" of the present invention is an activated integrin receptor, for example, an activated αvβ3 integrin receptor on a metastatic cell.

[0079] "Nonspecific T cell activation" refers to the stimulation of T cells independent of their antigenic specificity. [0080] "Effector cell" refers to an immune cell which is involved in the effector phase of an immune response, as opposed to the cognitive and activation phases of an immune response. Exemplary immune cells include a cell of a myeloid or lymphoid origin, e.g., lymphocytes (e.g., B cells and T cells including cytolytic T cells (CTLs)), killer cells, natural killer cells, macrophages, monocytes, eosinophils, neutrophils, polymorphonuclear cells, granulocytes, mast cells, and basophils. Effector cells express specific Fe receptors and carry out specific immune functions. An effector cell can induce antibody-dependent cell-mediated cytotoxicity (ADCC), e.g., a neutrophil capable of inducing ADCC. For example, monocytes, macrophages, neutrophils, eosinophils, and lymphocytes which express FcαR are involved in specific killing of target cells and presenting antigens to other components of the immune system, or binding to cells that present antigens. An effector cell can also phagocytose a target antigen, target cell, metastatic cancer cell, or microorganism.

[0081] "Target cell" refers to any undesirable cell in a subject (e.g., a human or animal) that can be targeted by the Ab or Ab composition of the invention. The target cell can be a cell expressing or overexpressing human activated integrin receptor. Cells expressing human activated integrin receptor can include metastatic tumor cells, e.g. breast cancer cells or metastatic breast cancer cells.

[0082] Targets of interest for antibody compositions on metastatic cancer cells, e.g., metastatic breast cancer cells, include, but are not limited to, cell surface receptors, growth factor receptors, antibodies, including anti-idiotypic antibodies and autoantibodies present in cancer, such as metastatic cancer and metastatic breast cancer. Other targets are adhesion proteins such as integrins, selectins, and immunoglobulin superfamily members. Springer, Nature, 346: 425- 433, 1990; Osborn, Cell, 62: 3, 1990; Hynes, Cell, 69: 11, 1992.

[0083] "Patient", "subject" or "mammal" are used interchangeably and refer to mammals such as human patients and non-human primates, as well as experimental animals such as rabbits, rats, and mice, and other animals. Animals include all vertebrates, e.g., mammals and non-mammals, such as sheep, dogs, cows, chickens, amphibians, and reptiles.

[0084] "Treating" or "treatment" includes the administration of the antibody compositions, compounds or agents of the present invention to prevent or delay the onset of the symptoms, complications, or biochemical indicia of a disease, alleviating the symptoms or arresting or inhibiting further development of the disease, condition, or disorder (e.g., cancer, metastatic cancer, or metastatic breast cancer). Treatment can be prophylactic (to prevent or delay the onset of the disease, or to prevent the manifestation of clinical or subclinical symptoms thereof) or therapeutic suppression or alleviation of symptoms after the manifestation of the disease.

[0085] "Cancer" or "malignancy" are used as synonymous terms and refer to any of a number of diseases that are characterized by uncontrolled, abnormal proliferation of cells, the ability of affected cells to spread locally or through the bloodstream and lymphatic system to other parts of the body (i.e., metastasize) as well as any of a number of characteristic structural and/or molecular features. A "cancerous" or "malignant cell" is understood as a cell having specific structural properties, lacking differentiation and being capable of invasion and metastasis. Examples of cancers are, breast, lung, brain, bone, liver, kidney, colon, and prostate cancer, (see DeVita et al, Eds., Cancer Principles and Practice of Oncology, 6th. Ed., Lippincott Williams & Wilkins, Philadelphia, PA, 2001; this reference is herein incorporated by reference in its entirety for all purposes).

[0086] "Cancer-associated" refers to the relationship of a nucleic acid and its expression, or lack thereof, or a protein and its level or activity, or lack thereof, to the onset of malignancy in a subject cell. For example, cancer can be associated with expression of a particular gene that is not expressed, or is expressed at a lower level, in a normal healthy cell. Conversely, a cancer-associated gene can be one that is not expressed in a malignant cell (or in a cell undergoing transformation), or is expressed at a lower level in the malignant cell than it is expressed in a normal healthy cell.

[0087] In the context of the cancer, the term "transformation" refers to the change that a normal cell undergoes as it becomes malignant. In eukaryotes, the term "transformation" can be used to describe the conversion of normal cells to malignant cells in cell culture.

[0088] "Proliferating cells" are those which are actively undergoing cell division and growing exponentially. "Loss of cell proliferation control" refers to the property of cells that have lost the cell cycle controls that normally ensure appropriate restriction of cell division. Cells that have lost such controls proliferate at a faster than normal rate, without stimulatory signals, and do not respond to inhibitory signals.

[0089] "Advanced cancer" means cancer that is no longer localized to the primary tumor site, or a cancer that is Stage III or IV according to the American Joint Committee on Cancer (AJCC).

[0090] "Well tolerated" refers to the absence of adverse changes in health status that occur as a result of the treatment and would affect treatment decisions. [0091] "Metastatic" refers to tumor cells, e.g., human breast cancer cells, that are able to establish secondary tumor lesions in the lungs, liver, bone or brain of immune deficient mice upon injection into the mammary fat pad and/or the circulation of the immune deficient mouse.

[0092] "Non-metastatic" refers to tumor cells, e.g., human breast cancer cells, that are unable to establish secondary tumor lesions in the lungs, liver, bone or brain or other target organs of breast cancer metastasis in immune deficient mice upon injection into the mammary fat pad and/or the circulation. The human tumor cells used herein and addressed herein as non- metastatic are able to establish primary tumors upon injection into the mammary fat pad of the immune deficient mouse, but they are unable to disseminate from those primary tumors.

[0093] "Lymphocyte" as used herein has the normal meaning in the art, and refers to any of the mononuclear, non-phagocytic leukocytes, found in the blood, lymph, and lymphoid tissues, e.g., B and T lymphocytes.

[0094] "Epitope" refers to a protein determinant capable of specific binding to an antibody. Epitopes usually consist of chemically active surface groupings of molecules such as amino acids or sugar side chains and usually have specific three dimensional structural characteristics, as well as specific charge characteristics. Conformational and non- conformational epitopes are distinguished in that the binding to the former but not the latter is lost in the presence of denaturing solvents.

scFv PHAGE LIBRARIES

[0095] One approach for a phage display library to identify an antibody composition that specifically binds to a cell surface receptor on a metastatic cell, for example, an activated integrin receptor, has been the use of scFv phage-libraries (see, e.g., Huston et ah, Proc. Natl. Acad. Sci U.S.A., 85: 5879-5883, 1988; Chaudhary et al, Proc. Natl. Acad. Sci U.S.A., 87: 1066- 1070, 1990. Various embodiments of scFv libraries displayed on bacteriophage coat proteins have been described. Refinements of phage display approaches are also known, for example as described in WO96/06213 and WO92/01047 (Medical Research Council et al.) and WO97/08320 (Morphosys), which are incorporated herein by reference. The display of Fab libraries is also known, for instance as described in WO92/01047 (CAT/MRC) and WO91/17271 (Affymax).

[0096] Hybrid antibodies or hybrid antibody fragments that are cloned into a display vector can be selected against the appropriate antigen associated with a metastatic cell, e.g. , a cell surface receptor or an activated cell surface receptor on a metastatic tumor cell, in order to identify variants that maintained good binding activity because the antibody or antibody fragment will be present on the surface of the phage or phagemid particle. See for example Barbas III et al. , Phage Display, A Laboratory Manual, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., 2001, the contents of which are incorporated herein by reference. For example, in the case of Fab fragments, the light chain and heavy chain Fd products are under the control of a lac promoter, and each chain has a leader signal fused to it in order to be directed to the periplasmic space of the bacterial host. It is in this space that the antibody fragments will be able to properly assemble. The heavy chain fragments are expressed as a fusion with a phage coat protein domain, which allows the assembled antibody fragment to be incorporated into the coat of a newly made phage or phagemid particle. Generation of new phagemid particles requires the addition of helper phage, which contain all the necessary phage genes. Once a library of antibody fragments is presented on the phage or phagemid surface, a process termed panning follows. This is a method whereby) the antibodies displayed on the surface of phage or phagemid particles are bound to the desired antigen, ii) non-binders are washed away, iii) bound particles are eluted from the antigen, and iv) eluted particles are exposed to fresh bacterial hosts in order to amplify the enriched pool for an additional round of selection. Typically three or four rounds of panning are performed prior to screening antibody clones for specific binding. In this way phage/phagemid particles allow the linkage of binding phenotype (antibody) with the genotype (DNA) making the use of antibody display technology very successful. However, other vector formats could be used for this humanization process, such as cloning the antibody fragment library into a lytic phage vector (modified T7 or Lambda Zap systems) for selection and/or screening.

[0097] After selection of desired hybrid antibodies and/or hybrid antibody fragments, it is contemplated that they can be produced in large volume by any technique known to those skilled in the art, e.g., prokaryotic or eukaryotic cell expression and the like. For example, hybrid antibodies or fragments may be produced by using conventional techniques to construct an expression vector that encodes an antibody heavy chain in which the CDRs and, if necessary, a minimal portion of the variable region framework, that are required to retain original species antibody binding specificity (as engineered according to the techniques described herein) are derived from the originating species antibody and the remainder of the antibody is derived from a target species immunoglobulin which may be manipulated as described herein, thereby producing a vector for the expression of a hybrid antibody heavy chain.

[0098] In a detailed embodiment, a single-chain Fv (scFv) antibody library can be prepared from the peripheral blood lymphocytes of 5, 10, 15, or 20 or more patients with various cancer diseases. Completely human high-affinity scFv antibodies can then be selected by using synthetic sialyl Lewis^x and Lewis^x BSA conjugates. In one study, these human scFv antibodies were specific for sialyl Lewis^x and Lewis^x, as demonstrated by ELISA, BIAcore, and flow cytometry binding to the cell surface of pancreatic adenocarcinoma cells. Nucleotide sequencing revealed that at least four unique scFv genes were obtained. The IQ values ranged from 1.1 to 6.2 x 10^"7 M that were comparable to the affinities of mAbs derived from the secondary immune response. These antibodies could be valuable reagents for probing the structure and function of carbohydrate antigens and in the treatment of human tumor diseases. Mao et ah, Proc. Natl. Acad. Sci. U.S.A. 96: 6953-6958, 1999.

[0099] In a further detailed embodiment, phage displayed combinatorial antibody libraries can be used to generate and select a wide variety of antibodies to an appropriate antigen associated with a metastatic cell, e.g. , a cell surface receptor or an activated cell surface receptor on a metastatic tumor cell. The phage coat proteins pVII and pIX can be used to display the heterodimeric structure of the antibody Fv region. Aspects of this technology have been extended to construct a large, human single-chain Fv (scFv) library of 4.5 x 10⁹ members displayed on pIX of filamentous bacteriophage. Furthermore, the diversity, quality, and utility of the library were demonstrated by the selection of scFv clones against six different protein antigens. Notably, more than 90% of the selected clones showed positive binding for their respective antigens after as few as three rounds of panning. Analyzed scFvs were also found to be of high affinity. For example, kinetic analysis (BIAcore) revealed that scFvs against staphylococcal enterotoxin B and cholera toxin B subunit had a nanomolar and subnanomolar dissociation constant, respectively, affording affinities comparable to, or exceeding that, of mAbs obtained from immunization. High specificity was also attained, not only between very distinct proteins, but also in the case of more closely related proteins, e.g., Ricinus communis ("ricin") agglutinins (RCA₆₀ and RCA₁₂₀), despite >80% sequence homology between the two. The results suggested that the performance of pIX-display libraries can potentially exceed that of the pill-display format and make it ideally suited for panning a wide variety of target antigens. Gao et al, Proc. Natl. Acad. Sci. U.S.A. 99: 12612-12616, 2001.

[0100] Specific binding between an antibody or other binding agent and an antigen means a binding affinity of at least 10^"6 M. Preferred binding agents bind with affinities of at least about 10^"7 M, and preferably 10^"8 M to 10^"9 M, 10^"10 M, 10^"11 M, or 10^"12 M. The term epitope means an antigenic determinant capable of specific binding to an antibody. Epitopes usually consist of chemically active surface groupings of molecules such as amino acids or sugar side chains and usually have specific three dimensional structural characteristics, as well as specific charge characteristics. Conformational and non-conformational epitopes are distinguished in that the binding to the former but not the latter is lost in the presence of denaturing solvents.

CANCER TREATMENT

[0101] Blockade of an activated αvβ3 integrin receptor by scFv-Fc antibody compositions can enhance the memory or secondary immune response to cancerous cells in the patient. Antibodies to activated αvβ3 integrin receptor can be combined with an immunogenic agent, such as cancerous cells, purified tumor antigens (including recombinant proteins, peptides, and carbohydrate molecules), cells, and cells transfected with genes encoding immune stimulating cytokines and cell surface antigens, or used alone, to stimulate immunity.

[0102] ScFv-Fc antibodies to activated αvβ3 integrin receptor are effective when following a vaccination protocol. Many experimental strategies for vaccination against tumors have been devised (see Rosenberg, ASCO Educational Book Spring: 60-62, 2000; Logothetis, ASCO Educational Book Spring: 300-302, 2000; Khayat, ASCO Educational Book Spring: 414- 428, 2000; Foon, ASCO Educational Book Spring: 730-738, 2000; see also Restifo et ah, Cancer: Principles and Practice of Oncology, 61: 3023-3043, 1997. In one of these strategies, a vaccine is prepared using autologous or allogeneic tumor cells. These cellular vaccines have been shown to be most effective when the tumor cells are transduced to express GM-CSF. GM- CSF has been shown to be a potent activator of antigen presentation for tumor vaccination. Dranoff et al, Proc. Natl. Acad. Sci U.S.A., 90: 3539-43, 1993.

[0103] ScFv-Fc antibodies to activated αvβ3 integrin receptor can boost GM-CSF- modified tumor cell vaccines improves efficacy of vaccines in a number of experimental tumor models such as mammary carcinoma, primary prostate cancer (Hurwitz et ah, Cancer Research, 60: 2444-8, 2000) and melanoma (van Elsas et ah, J. Exp. Med., 190: 355-66, 1999). In these instances, non-immunogenic tumors, such as the B 16 melanoma, have been rendered susceptible to destruction by the immune system. The tumor cell vaccine can also be modified to express other immune activators such as IL2, and costimulatory molecules, among others.

[0104] The study of gene expression and large scale gene expression patterns in various tumors has led to the definition of so called "tumor specific antigens" (Rosenberg, Immunity, 10: 281-7, 1999). In many cases, these tumor specific antigens are differentiation antigens expressed in the tumors and in the cell from which the tumor arose, for example melanocyte antigens gplOO, MAGE antigens, Trp-2. More importantly, many of these antigens can be shown to be the targets of tumor specific T cells found in the host. Antibodies to activated integrin receptor can be used as a boosting agent in conjunction with vaccines based on recombinant versions of proteins and/or peptides found to be expressed in a tumor in order to potentiate a secondary or memory immune response to these proteins. These proteins are normally viewed by the immune system as self antigens and are therefore tolerant to them. The tumor antigen can also include the protein telomerase, which is required for the synthesis of telomeres of chromosomes and which is expressed in more than 85% of human cancers and in only a limited number of somatic tissues (Kim et al, Science, 266: 2011-2013, 1994). These somatic tissues can be protected from immune attack by various means. Tumor antigen can also be "neo-antigens" expressed in cancer cells because of somatic mutations that alter protein sequence or create fusion proteins between two unrelated sequences {e.g. bcr-abl in the Philadelphia chromosome), or idiotype from B cell tumors. Other tumor vaccines can include the proteins from viruses implicated in human cancers such a Human Papilloma Viruses (HPV), Hepatitis Viruses (HBV and HCV) and Kaposi's Herpes Sarcoma Virus (KHSV). Another form of tumor specific antigen which can be used in conjunction with antibodies to activated integrin receptor is purified heat shock proteins (HSP) isolated from the tumor tissue itself. These heat shock proteins contain fragments of proteins from the tumor cells and these HSPs are highly efficient at delivery to antigen presenting cells for eliciting tumor immunity (Suot et al, Science, 269: 1585-1588, 1995; Tamura et al, Science, 278: 117-120, 1997.

[0105] Dendritic cells (DC) are potent antigen presenting cells that can be used to prime antigen- specific responses to activated αvβ3 integrin receptors on metastatic tumor cells. DCs can be produced ex vivo and loaded with various protein and peptide antigens as well as tumor cell extracts (Nestle et al, Nature Medicine, 4: 328-332, 1998). DCs can also be transduced by genetic means to express these tumor antigens as well. DCs have also been fused directly to tumor cells for the purposes of immunization (Kugler et al, Nature Medicine, 6: 332- 336, 2000). As a method of vaccination, DC immunization can be effectively boosted with antibodies to activated integrin receptor to activate more potent anti-tumor responses.

[0106] Another type of melanoma vaccine that can be combined with antibodies to activated αvβ3 integrin receptor is a vaccine prepared from a melanoma cell line lysate, in conjunction with an immunological adjuvant, such as the MELACINE™ vaccine, a mixture of lysates from two human melanoma cell lines plus DETOX™ immunological adjuvant. Vaccine treatment can be boosted with anti-activated integrin receptor, with or without additional chemotherapeutic treatment.

[0107] Antibodies to activated αvβ3 integrin receptor can also be used to boost immunity induced through standard cancer treatments. In these instances, it can be possible to reduce the dose of chemotherapeutic reagent administered (Mokyr et al, Cancer Research, 58: 5301-5304, 1998). The scientific rationale behind the combined use of antibodies to activated integrin receptor and chemotherapy is that cell death, that is a consequence of the cytotoxic action of most chemotherapeutic compounds, should result in increased levels of tumor antigen in the antigen presentation pathway. Thus, antibodies to activated integrin receptor can boost an immune response primed to chemotherapy release of tumor cells. Examples of chemotherapeutic agents combined with treatment with antibodies to activated integrin receptor can include, but are not limited to, aldesleukin, altretamine, amifostine, asparaginase, bleomycin, capecitabine, carboplatin, carmustine, cladribine, cisapride, cisplatin, cyclophosphamide, cytarabine, dacarbazine (DTIC), dactinomycin, docetaxel, doxorubicin, dronabinol, duocarmycin, epoetin alpha, etoposide, filgrastim, fludarabine, fluorouracil, gemcitabine, granisetron, hydroxyurea, idarubicin, ifosfamide, interferon alpha, irinotecan, lansoprazole, levamisole, leucovorin, megestrol, mesna, methotrexate, metoclopramide, mitomycin, mitotane, mitoxantrone, omeprazole, ondansetron, paclitaxel (Taxol™), pilocarpine, prochloroperazine, rituximab, saproin, tamoxifen, taxol, topotecan hydrochloride, trastuzumab, vinblastine, vincristine and vinorelbine tartrate. For prostate cancer treatment, a preferred chemotherapeutic agent with which anti-activated integrin receptor can be combined is paclitaxel (Taxol™). For melanoma cancer treatment, a preferred chemotherapeutic agent with which anti-activated integrin receptor can be combined is dacarbazine (DTIC).

[0108] Other combination therapies that can result in immune system priming through cell death are radiation, surgery, and hormone deprivation (Kwon et al. , Proc. Natl. Acad. Sci U.S.A., 96: 15074-9, 1999. Each of these protocols creates a source of tumor antigen in the host. For example, any manipulation of the tumor at the time of surgery can greatly increase the number of cancer cells in the blood (Schwartz et al, Principles of Surgery. 4^th ed., p.338, 1984). Angiogenesis inhibitors can also be combined with antibodies to activated integrin receptor. Inhibition of angiogenesis leads to tumor cell death which can feed tumor antigen into host antigen presentation pathways. All of these cause tumor release and possible immune system priming that antibodies to activated integrin receptor can boost.

THERAPEUTIC APPLICATIONS

[0109] The scFv5-Fc or scFvl-Fc polypeptide, or mimetic, analog or derivative thereof, identified by the methods as described herein can be used in a variety of methods of treatment of metastatic disease, e.g., metastatic breast cancer. Thus, the present invention provides compositions and methods for treating metastatic cancer. The composition includes a scFv5-Fc or scFvl-Fc polypeptide, or mimetic, analog or derivative thereof, and a pharmaceutically acceptable carrier. The scFv5 or scFvl composition can be administered alone or in combination with other compositions.

[0110] A scFv5 or scFvl polypeptide, or mimetic, analog or derivative thereof, as described herein, can be used in methods for preventing or treating metastatic disease, e.g. , metastatic breast cancer in a mammalian subject.

[0111] Preferably, treatment using scFv5-Fc or scFvl-Fc polypeptide, or mimetic, analog or derivative thereof, in an aspect of the present invention could either be by administering an effective amount of the scFv5-Fc or scFvl-Fc polypeptide to the patient. Moreover, the polypeptide or peptidomimetic as provided herein can be used to reduce or eliminate metastatic cancer.

[0112] "Antineoplastic agent" is used herein to refer to agents that have the functional property of inhibiting a development or progression of a neoplasm in a human, particularly a malignant (cancerous) lesion, such as a carcinoma, sarcoma, lymphoma, or leukemia. Inhibition of metastasis is frequently a property of antineoplastic agents.

[0113] A "solid tumor" includes, but is not limited to, sarcoma, melanoma, carcinoma, or other solid tumor cancer.

[0114] "Sarcoma" refers to a tumor which is made up of a substance like the embryonic connective tissue and is generally composed of closely packed cells embedded in a fibrillar or homogeneous substance. Sarcomas include, but are not limited to, chondrosarcoma, fibrosarcoma, lymphosarcoma, melanosarcoma, myxosarcoma, osteosarcoma, Abemethy's sarcoma, adipose sarcoma, liposarcoma, alveolar soft part sarcoma, ameloblastic sarcoma, botryoid sarcoma, chloroma sarcoma, chorio carcinoma, embryonal sarcoma, Wilms' tumor sarcoma, endometrial sarcoma, stromal sarcoma, Ewing's sarcoma, fascial sarcoma, fibroblastic sarcoma, giant cell sarcoma, granulocytic sarcoma, Hodgkin's sarcoma, idiopathic multiple pigmented hemorrhagic sarcoma, immunoblastic sarcoma of B cells, lymphoma, immunoblastic sarcoma of T-cells, Jensen's sarcoma, Kaposi's sarcoma, Kupffer cell sarcoma, angiosarcoma, leukosarcoma, malignant mesenchymoma sarcoma, parosteal sarcoma, reticulocytic sarcoma, Rous sarcoma, serocystic sarcoma, synovial sarcoma, and telangiectatic sarcoma.

[0115] "Melanoma" refers to a tumor arising from the melanocytic system of the skin and other organs. Melanomas include, for example, acral-lentiginous melanoma, amelanotic melanoma, benign juvenile melanoma, Cloudman's melanoma, S91 melanoma, Harding-Passey melanoma, juvenile melanoma, lentigo maligna melanoma, malignant melanoma, nodular melanoma, subungal melanoma, and superficial spreading melanoma. [0116] "Carcinoma" refers to a malignant new growth made up of epithelial cells tending to infiltrate the surrounding tissues and give rise to metastases. Exemplary carcinomas include, for example, acinar carcinoma, acinous carcinoma, adenocystic carcinoma, adenoid cystic carcinoma, carcinoma adenomatosum, carcinoma of adrenal cortex, alveolar carcinoma, alveolar cell carcinoma, basal cell carcinoma, carcinoma basocellulare, basaloid carcinoma, basosquamous cell carcinoma, bronchioalveolar carcinoma, bronchiolar carcinoma, bronchogenic carcinoma, cerebriform carcinoma, cholangiocellular carcinoma, chorionic carcinoma, colloid carcinoma, comedo carcinoma, corpus carcinoma, cribriform carcinoma, carcinoma en cuirasse, carcinoma cutaneum, cylindrical carcinoma, cylindrical cell carcinoma, duct carcinoma, carcinoma durum, embryonal carcinoma, encephaloid carcinoma, epiermoid carcinoma, carcinoma epitheliale adenoides, exophytic carcinoma, carcinoma ex ulcere, carcinoma fϊbrosum, gelatiniform carcinoma, gelatinous carcinoma, giant cell carcinoma, carcinoma gigantocellulare, glandular carcinoma, granulosa cell carcinoma, hair-matrix carcinoma, hematoid carcinoma, hepatocellular carcinoma, Hurthle cell carcinoma, hyaline carcinoma, hypemephroid carcinoma, infantile embryonal carcinoma, carcinoma in situ, intraepidermal carcinoma, intraepithelial carcinoma, Krompecher's carcinoma, Kulchitzky-cell carcinoma, large-cell carcinoma, lenticular carcinoma, carcinoma lenticulare, lipomatous carcinoma, lymphoepithelial carcinoma, carcinoma medullare, medullary carcinoma, melanotic carcinoma, carcinoma molle, mucinous carcinoma, carcinoma muciparum, carcinoma mucocellulare, mucoepidernoid carcinoma, carcinoma mucosum, mucous carcinoma, carcinoma myxomatodes, naspharyngeal carcinoma, oat cell carcinoma, carcinoma ossificans, osteoid carcinoma, papillary carcinoma, periportal carcinoma, preinvasive carcinoma, prickle cell carcinoma, pultaceous carcinoma, renal cell carcinoma of kidney, reserve cell carcinoma, carcinoma sarcomatodes, schneiderian carcinoma, scirrhous carcinoma, carcinoma scroti, signet- ring cell carcinoma, carcinoma simplex, small-cell carcinoma, solanoid carcinoma, spheroidal cell carcinoma, spindle cell carcinoma, carcinoma spongiosum, squamous carcinoma, squamous cell carcinoma, string carcinoma, carcinoma telangiectaticum, carcinoma telangiectodes, transitional cell carcinoma, carcinoma tuberosum, tuberous carcinoma, verrucous carcinoma, and carcinoma viflosum.

[0117] "Leukemia" refers to progressive, malignant diseases of the blood-forming organs and is generally characterized by a distorted proliferation and development of leukocytes and their precursors in the blood and bone marrow. Leukemia is generally clinically classified on the basis of (1) the duration and character of the disease—acute or chronic; (2) the type of cell involved; myeloid (myelogenous), lymphoid (lymphogenous), or monocytic; and (3) the increase or non-increase in the number of abnormal cells in the blood—leukemic or aleukemic (subleukemic). Leukemia includes, for example, acute nonlymphocytic leukemia, chronic lymphocytic leukemia, acute granulocytic leukemia, chronic granulocytic leukemia, acute promyelocytic leukemia, adult T-cell leukemia, aleukemic leukemia, a leukocythemic leukemia, basophylic leukemia, blast cell leukemia, bovine leukemia, chronic myelocytic leukemia, leukemia cutis, embryonal leukemia, eosinophilic leukemia, Gross' leukemia, hairy-cell leukemia, hemoblastic leukemia, hemocytoblastic leukemia, histiocytic leukemia, stem cell leukemia, acute monocytic leukemia, leukopenic leukemia, lymphatic leukemia, lymphoblastic leukemia, lymphocytic leukemia, lymphogenous leukemia, lymphoid leukemia, lymphosarcoma cell leukemia, mast cell leukemia, megakaryocytic leukemia, micromyeloblastic leukemia, monocytic leukemia, myeloblasts leukemia, myelocytic leukemia, myeloid granulocytic leukemia, myelomonocytic leukemia, Naegeli leukemia, plasma cell leukemia, plasmacytic leukemia, promyelocytic leukemia, Rieder cell leukemia, Schilling's leukemia, stem cell leukemia, subleukemic leukemia, and undifferentiated cell leukemia.

[0118] Additional cancers include, for example, Hodgkin's Disease, Non-Hodgkin's Lymphoma, multiple myeloma, neuroblastoma, breast cancer, ovarian cancer, lung cancer, rhabdomyosarcoma, primary thrombocytosis, primary macroglobulinemia, small-cell lung tumors, primary brain tumors, stomach cancer, colon cancer, malignant pancreatic insulanoma, malignant carcinoid, urinary bladder cancer, premalignant skin lesions, testicular cancer, lymphomas, thyroid cancer, neuroblastoma, esophageal cancer, genitourinary tract cancer, malignant hypercalcemia, cervical cancer, endometrial cancer, adrenal cortical cancer, and prostate cancer.

PHARMACEUTICAL COMPOSITIONS

[0119] Antibodies scFv5-Fc or scFvl-Fc, or mimetic, analog or derivative thereof, useful in the present compositions and methods can be administered to a human patient per se, in the form of a stereoisomer, prodrug, pharmaceutically acceptable salt, hydrate, solvate, acid salt hydrate, N-oxide or isomorphic crystalline form thereof, or in the form of a pharmaceutical composition where the compound is mixed with suitable carriers or excipient(s) in a therapeutically effective amount, for example, to treat metastatic disease, e.g., metastatic breast cancer.

[0120] "Therapeutically effective amount" refers to that amount of the therapeutic agent, scFv5-Fc or scFvl-Fc antibody, or mimetic, analog or derivative thereof, sufficient to result in the amelioration of one or more symptoms of a disorder, or prevent advancement of a disorder, cause regression of the disorder, or to enhance or improve the therapeutic effect(s) of another therapeutic agent. With respect to the treatment of metastatic cancer, a therapeutically effective amount refers to the amount of a therapeutic agent sufficient to reduce or eliminate metastatic cancer. Preferably, a therapeutically effective amount of a therapeutic agent reduces or eliminates metastatic cancer, by at least 5%, preferably at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or at least 100%. With respect to the treatment of metastatic cancer, a therapeutically effective amount refers to the amount of a therapeutic agent that reduces the disease by at least 5%, preferably at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or at least 100%. "Therapeutic protocol" refers to a regimen for dosing and timing the administration of one or more therapeutic agents, such as scFv5-Fc or scFvl-Fc antibody, or mimetic, analog or derivative thereof.

[0121] Pharmaceutically acceptable carriers are determined in part by the particular composition being administered, as well as by the particular method used to administer the composition. Accordingly, there is a wide variety of suitable formulations of pharmaceutical compositions for administering the antibody compositions (see, e.g., latest edition of Remington's Pharmaceutical Sciences, Mack Publishing Co., Easton, PA, incorporated herein by reference). The pharmaceutical compositions generally comprise a differentially expressed protein, scFv5-Fc or scFvl-Fc antibody, or mimetic, analog or derivative thereof, in a form suitable for administration to a patient. The pharmaceutical compositions are generally formulated as sterile, substantially isotonic and in full compliance with all Good Manufacturing Practice (GMP) regulations of the U.S. Food and Drug Administration.

TREATMENT REGIMES

[0122] Aspects of the invention provide pharmaceutical compositions comprising one or a combination of scFv5-Fc or scFvl-Fc antibodies, or mimetic, analog or derivative thereof, formulated together with a pharmaceutically acceptable carrier. Some compositions include a combination of multiple {e.g., two or more) scFv5-Fc or scFvl-Fc antibodies, or mimetic, analog or derivative thereof.

[0123] In prophylactic applications, pharmaceutical compositions or medicaments are administered to a patient susceptible to, or otherwise at risk of a disease or condition (i.e., metastatic cancer) in an amount sufficient to eliminate or reduce the risk, lessen the severity, or delay the outset of the disease, including biochemical, histologic and/or behavioral symptoms of the disease, its complications and intermediate pathological phenotypes presenting during development of the disease. In therapeutic applications, compositions or medicaments are administered to a patient suspected of, or already suffering from such a disease in an amount sufficient to cure, or at least partially arrest, the symptoms of the disease (biochemical, histologic and/or behavioral), including its complications and intermediate pathological phenotypes in development of the disease. An amount adequate to accomplish therapeutic or prophylactic treatment is defined as a therapeutically- or prophalactically-effective dose. In both prophylactic and therapeutic regimes, agents are usually administered in several dosages until a sufficient immune response has been achieved. Typically, the immune response is monitored and repeated dosages are given if the immune response starts to wane.

EFFECTIVE DOSAGES

[0124] Effective doses of scFv5-Fc or scFvl-Fc antibody, or mimetic, analog or derivative thereof, for the treatment of metastatic disease, e.g., metastatic breast cancer, as described herein vary depending upon many different factors, including means of administration, target site, physiological state of the patient, whether the patient is human or an animal, other medications administered, and whether treatment is prophylactic or therapeutic. Usually, the patient is a human but nonhuman mammals including transgenic mammals can also be treated. Treatment dosages need to be titrated to optimize safety and efficacy.

[0125] For administration with scFv5-Fc or scFvl-Fc antibody, or mimetic, analog or derivative thereof, the dosage ranges from about 0.0001 to 100 mg/kg, and more usually 0.01 to 5 mg/kg, of the host body weight. For example dosages can be 1 mg/kg body weight or 10 mg/kg body weight or within the range of 1-10 mg/kg. An exemplary treatment regime entails administration once per every two weeks or once a month or once every 3 to 6 months. In some methods, two or more scFv5-Fc or scFvl-Fc antibodies, or mimetic, analog or derivative thereof, with different binding specificities are administered simultaneously, in which case the dosage of each scFv5-Fc or scFvl-Fc antibody is usually administered on multiple occasions. Intervals between single dosages can be weekly, monthly or yearly. Intervals can also be irregular as indicated by measuring blood levels of scFv5-Fc or scFvl-Fc antibody in the patient. In some methods, dosage is adjusted to achieve an concentration of 1-1000 μg/ml scFv5-Fc or scFvl-Fc antibody and in some methods 25-300 μg/ml. Alternatively, scFv5-Fc or scFvl-Fc antibody, or mimetic, analog or derivative thereof can be administered as a sustained release formulation, in which case less frequent administration is required. Dosage and frequency vary depending on the half- life of the compound in the patient. The dosage and frequency of administration can vary depending on whether the treatment is prophylactic or therapeutic. In prophylactic applications, a relatively low dosage is administered at relatively infrequent intervals over a long period of time. Some patients continue to receive treatment for the rest of their lives. In therapeutic applications, a relatively high dosage at relatively short intervals is sometimes required until progression of the disease is reduced or terminated, and preferably until the patient shows partial or complete amelioration of symptoms of metastatic cancer. Thereafter, the patent can be administered a prophylactic regime.

[0126] Doses for a nucleic acid vector encoding scFv5-Fc or scFvl-Fc antibody, or mimetic, analog or derivative thereof, range from about 10 ng to 1 g, 100 ng to 100 mg, 1 μg to 10 mg, or 30-300 μg DNA per patient. Doses for infectious viral vectors vary from 10-100, or more, virions per dose.

PRODRUGS

[0127] The present invention is also related to prodrugs of the agents obtained by the methods disclosed herein. Prodrugs are agents which are converted in vivo to active forms (see, e.g., R.B. Silverman, 1992, The Organic Chemistry of Drug Design and Drug Action, Academic Press, Ch. 8). Prodrugs can be used to alter the biodistribution {e.g., to allow agents which would not typically enter the reactive site of the protease) or the pharmacokinetics for a particular agent. For example, a carboxylic acid group, can be esterified, e.g., with a methyl group or an ethyl group to yield an ester. When the ester is administered to a subject, the ester is cleaved, enzymatically or non-enzymatically, reductively, oxidatively, or hydrolytically, to reveal the anionic group. An anionic group can be esterified with moieties {e.g., acyloxymethyl esters) which are cleaved to reveal an intermediate agent which subsequently decomposes to yield the active agent. The prodrug moieties may be metabolized in vivo by esterases or by other mechanisms to carboxylic acids.

[0128] Examples of prodrugs and their uses are well known in the art (see, e.g., Berge et al., "Pharmaceutical Salts", J. Pharm. Sci. 66: 1-19, 1977). The prodrugs can be prepared in situ during the final isolation and purification of the agents, or by separately reacting the purified agent in its free acid form with a suitable derivatizing agent. Carboxylic acids can be converted into esters via treatment with an alcohol in the presence of a catalyst.

[0129] Examples of cleavable carboxylic acid prodrug moieties include substituted and unsubstituted, branched or unbranched lower alkyl ester moieties, {e.g., ethyl esters, propyl esters, butyl esters, pentyl esters, cyclopentyl esters, hexyl esters, cyclohexyl esters), lower alkenyl esters, dilower alkyl-amino lower-alkyl esters {e.g., dimethylaminoethyl ester), acylamino lower alkyl esters, acyloxy lower alkyl esters {e.g., pivaloyloxymethyl ester), aryl esters (phenyl ester), aryl-lower alkyl esters {e.g., benzyl ester), substituted {e.g., with methyl, halo, or methoxy substituents) aryl and aryl-lower alkyl esters, amides, lower-alkyl amides, dilower alkyl amides, and hydroxy amides.

ROUTES OF ADMINISTRATION

[0130] Antibodies scFv5-Fc or scFvl-Fc, or mimetic, analog or derivative thereof, for treatment or amelioration of metastatic disease, e.g., metastatic breast cancer can be administered by parenteral, topical, intravenous, oral, subcutaneous, intraarterial, intracranial, intraperitoneal, intranasal or intramuscular means for prophylactic as inhalants for scFv5-Fc or scFvl-Fc antibody, or mimetic, analog or derivative thereof, preparations targeting metastatic cancer in tissues of the mammalian subject. The most typical route of administration of an antibody agent is subcutaneous although other routes can be equally effective. The next most common route is intramuscular injection. This type of injection is most typically performed in the arm or leg muscles. In some methods, agents are injected directly into a particular tissue where a tumor is found, for example intracranial injection or convection enhanced delivery. Intramuscular injection or intravenous infusion are preferred for administration of antibody. In some methods, particular therapeutic antibodies are delivered directly into the cranium. In some methods, antibodies are administered as a sustained release composition or device, such as a Medipad™ device.

[0131] Isolated scFv-Fc antibodies of the invention can optionally be administered in combination with other agents that are at least partly effective in treating metastatic cancer. In the case of disease in the brain, agents of the invention can also be administered in conjunction with other agents that increase passage of the agents of the invention across the blood-brain barrier (BBB) to treat metastatic cancer.

FORMULATION

[0132] Antibodies scFv5-Fc or scFvl-Fc, or mimetic, analog or derivative thereof, for the treatment of metastatic disease, e.g., metastatic breast cancer, are often administered as pharmaceutical compositions comprising an active therapeutic agent, i.e., and a variety of other pharmaceutically acceptable components. See latest edition of Remington's Pharmaceutical Science (Mack Publishing Company, Easton, Pa.). The preferred form depends on the intended mode of administration and therapeutic application. The compositions can also include, depending on the formulation desired, pharmaceutically-acceptable, non-toxic carriers or diluents, which are defined as vehicles commonly used to formulate pharmaceutical compositions for animal or human administration. The diluent is selected so as not to affect the biological activity of the combination. Examples of such diluents are distilled water, physiological phosphate-buffered saline, Ringer's solutions, dextrose solution, and Hank's solution. In addition, the pharmaceutical composition or formulation may also include other carriers, adjuvants, or nontoxic, nontherapeutic, nonimmunogenic stabilizers and the like.

[0133] Pharmaceutical compositions can also include large, slowly metabolized macromolecules such as proteins, polysaccharides such as chitosan, polylactic acids, polyglycolic acids and copolymers (such as latex functionalized Sepharose™, agarose, cellulose, and the like), polymeric amino acids, amino acid copolymers, and lipid aggregates (such as oil droplets or liposomes). Additionally, these carriers can function as immunostimulating agents (i.e., adjuvants).

[0134] For parenteral administration, compositions of aspects of the invention can be administered as injectable dosages of a solution or suspension of the substance in a physiologically acceptable diluent with a pharmaceutical carrier that can be a sterile liquid such as water oils, saline, glycerol, or ethanol. Additionally, auxiliary substances, such as wetting or emulsifying agents, surfactants, pH buffering substances and the like can be present in compositions. Other components of pharmaceutical compositions are those of petroleum, animal, vegetable, or synthetic origin, for example, peanut oil, soybean oil, and mineral oil. In general, glycols such as propylene glycol or polyethylene glycol are preferred liquid carriers, particularly for injectable solutions. Antibodies can be administered in the form of a depot injection or implant preparation which can be formulated in such a manner as to permit a sustained release of the active ingredient. An exemplary composition comprises scFv-Fc antibody at 5 mg/mL, formulated in aqueous buffer consisting of 50 mM L-histidine, 150 mM NaCl, adjusted to pH 6.0 with HCl.

[0135] Typically, compositions are prepared as injectables, either as liquid solutions or suspensions; solid forms suitable for solution in, or suspension in, liquid vehicles prior to injection can also be prepared. The preparation also can be emulsified or encapsulated in liposomes or micro particles such as polylactide, polyglycolide, or copolymer for enhanced adjuvant effect, as discussed above. Langer, Science 249: 1527, 1990 and Hanes, Advanced Drug Delivery Reviews 28: 97-119, 1997. The agents of this invention can be administered in the form of a depot injection or implant preparation which can be formulated in such a manner as to permit a sustained or pulsatile release of the active ingredient.

[0136] Additional formulations suitable for other modes of administration include oral, intranasal, and pulmonary formulations, suppositories, and transdermal applications.

[0137] For suppositories, binders and carriers include, for example, polyalkylene glycols or triglycerides; such suppositories can be formed from mixtures containing the active ingredient in the range of 0.5% to 10%, preferably l%-2%. Oral formulations include excipients, such as pharmaceutical grades of mannitol, lactose, starch, magnesium stearate, sodium saccharine, cellulose, and magnesium carbonate. These compositions take the form of solutions, suspensions, tablets, pills, capsules, sustained release formulations or powders and contain 10%- 95% of active ingredient, preferably 25%-70%.

[0138] Topical application can result in transdermal or intradermal delivery. Topical administration can be facilitated by co-administration of the agent with cholera toxin or detoxified derivatives or subunits thereof or other similar bacterial toxins. Glenn et al., Nature 391: 851, 1998. Co-administration can be achieved by using the components as a mixture or as linked molecules obtained by chemical crosslinking or expression as a fusion protein.

[0139] Alternatively, transdermal delivery can be achieved using a skin patch or using transferosomes. Paul et al., Eur. J. Immunol. 25: 3521-24, 1995; Cevc et al., Biochem. Biophys. Acta 1368: 201-15, 1998.

[0140] The pharmaceutical compositions are generally formulated as sterile, substantially isotonic and in full compliance with all Good Manufacturing Practice (GMP) regulations of the U.S. Food and Drug Administration.

TOXICITY

[0141] Preferably, a therapeutically effective dose of scFv5-Fc or scFvl-Fc antibody, or mimetic, analog or derivative thereof, described herein will provide therapeutic benefit without causing substantial toxicity.

[0142] Toxicity of the proteins described herein can be determined by standard pharmaceutical procedures in cell cultures or experimental animals, e.g., by determining the LD50 (the dose lethal to 50% of the population) or the LD100 (the dose lethal to 100% of the population). The dose ratio between toxic and therapeutic effect is the therapeutic index. The data obtained from these cell culture assays and animal studies can be used in formulating a dosage range that is not toxic for use in human. The dosage of the proteins described herein lies preferably within a range of circulating concentrations that include the effective dose with little or no toxicity. The dosage can vary within this range depending upon the dosage form employed and the route of administration utilized. The exact formulation, route of administration and dosage can be chosen by the individual physician in view of the patient's condition. (See, e.g., Fingl et al., 1975, In: The Pharmacological Basis of Therapeutics, Ch. 1, KITS

[0143] Also within the scope of the invention are kits comprising scFv5-Fc or scFvl-Fc antibody, or mimetic, analog or derivative thereof, of aspects of the invention and instructions for use. The kit can further contain a least one additional reagent, or one or more additional human antibodies of aspects of the invention (e.g., a human antibody having a complementary activity which binds to an epitope in the antigen distinct from the first human antibody). Kits typically include a label indicating the intended use of the contents of the kit. The term label includes any writing, or recorded material supplied on or with the kit, or which otherwise accompanies the kit.

[0144] The invention will be further described with reference to the following examples; however, it is to be understood that the invention is not limited to such examples.

[0145] The following examples of specific aspects for carrying out the present invention are offered for illustrative purposes only, and are not intended to limit the scope of the present invention in any way.

EXEMPLARY EMBODIMENTS

EXAMPLE 1

Construction and Expression of scFv5-Fc Antibody

[0146] An expression construct has been generated and scFv5-Fc protein has successfully been expressed in mammalian cells. The fusion protein scFv5-Fc has been purified and analyzed for its binding ability to cancer cells using flow cytometric methodologies. The scFv antibodies: scFv5 and scFvl are equivalent to antibodies scFv Bcl5 and scFv Bc 12, respectively. ; U.S. Patent No. 7,271,245-Habermann, et al, Proc Natl Acad Sci USA, 101: 17210-17215, 2004.

[0147] Construction of the Fab5 gene. The generation of human Fab fragment required a series of PCR steps. Steiniger, et al., MoI Immunol. 44: 2749-2755, 2007. In the first PCR, the individual VH, VL, C_HI , and C_K genes were amplified separately and combined in a second overlap PCR to generate the heavy-chain fragment (V_H/C_RI) and the light chain fragment (V_L/C_K). The third PCR step served to amplify a full-length product through overlap extension that contains both chains with one behind the other. Specific oligonucleotides primers were used to amplify V_H and V_L gene segments from purified DNA for the primary PCR. The following primers were used: VH3: 5' GGCC CAG CCG GCC ATG GCA SAG GTC CAG CTG GTA CAG TCT GG, and BJCH3: 5' TGGT GGA GGC TGA GGA GAC GGT GAC CRK GGT BCC; Vkl2: 5' TACC GTG GCC CAG GCA GCT GAA ATT GTG CTG ACT CAG TCT CC and JK3: 5' AGA TGG TGC AGC CAC AGT TCG TTT GAT HTC AAG CTT GGT CCC. The genes for the human constant regions CHl and CK were amplified from a template Fab gene² using the following primers: BCH5: 5' GGT CAC CGT CTC CTC AGC CTC CAC and VLOM3: 5' AGC TGC CTG GGC CAC GGT AGC G; CK5: 5' CGA ACT GTG GCT GCA CCA TCT and CKsfi: 5' CTCGTC GAC TGG AAT TCG GCC CCC GAG GCC AC. Larsen, et al, JMo/ Biol. 311: 9-15, 2001. The secondary PCR served as an assembly for the V_H/C_H1 fragment and the Vi/C_κ fragment. The assembled product was amplified in a third PCR with the primers VHsfi and CKsfi - VHsfi: 5' TTG TTA TTA CTC GCG GCC CAG CCG GCC ATG GCA and CKsfi: 5' CTC GCT GAC TGG AAT TCG GCC CCC GAG GCC AC. The resulting 1500 bp PCR product had Sfil restriction endonuclease sites on the 5' and 3' ends that were used for cloning into the phagemid vectors. After collection and purification the PCR product was digested with Sfil and subcloned into pET-FLAG and purified.

[0148] Fab expression and purification. PCR fragments encoding Fab genes were generated by overlap extension PCR, cloned into pET-FLAG vector and transformed into E. coli BL21 (DE3). Expression was induced with 1 mM isopropyl β-d-thiogalactoside. Fab protein was purified from the concentrated supernatants of induced cultures and from the periplasmic space. FLAG-tagged Fab fragments were purified by anti-FLAG affinity chromatography. The purified Fabs were dialyzed against PBS and protein concentration was determined from the absorbance at 280 nm. The quality of the preparations was assessed by reducing and non-reducing SDS- PAGE followed by Coomassie staining.

[0149] Generation ofscFv5- and Fab 5 -displaying phage particles. Escherichia coli TGl cells (Stratagene) were transformed with the phagemid encoding containing the scFv5 gene or Fab5 gene. E. coli TGl cultures were grown in 2 x 0.5 liters of 2YT broth in the presence of the antibiotic carbenicillin (100 μg/ml). Upon an optical density at a wavelength at 600 nm (OD₆₀₀) of 0.8, the cells were infected with 0.5 ml of VCS M13 helper phage (Stratagene) (10¹² plaque-forming units/ml). After 30 min incubation at room temperature, the culture was grown for 2 h at 37°C. Kanamycin/isopropyl β-D-thiogalactoside were then added to a final concentration of 70 μg/ml, and the culture was grown overnight at 30⁰C. After growth overnight, the bacterial cells were removed by centrifugation, and phage particles were harvested from the supernatant by precipitation with NaCl (3% wt/vol) and polyethylene glycol (PEG) 8000 (4% wt/vol). The phage pellet was resuspended in sterile endotoxin-free PBS (Invitrogen) and precipitated again. Upon resuspension of the pellet in 4 ml of PBS, the phage solution was filtered through a pyrogen-free 0.45-μm cellulose-acetate filter to remove any remaining bacterial cells. The phage preparation was titered, i.e., the number of colony forming units was determined according to standard protocols.

EXAMPLE 2

Construction and Expression of IgG5

[0150] Construction of IgG Expression Plasmid. The V_H and V_L-C_L sequences of Fab 5 in pET plasmid were amplified by PCR and combined with the leader sequences of Ig heavy and light chains, respectively, by recombinant PCR using proper primers. The PCR-amplified DNA fragments of V_R and V_L-C_K with leader sequences were sequentially subcloned into the EcoRI- Apal and Hindlll-Xbal sites, respectively, of the antibody expression plasmid pdCMV-dhfrC containing the human γl constant regions.

[0151] Cell Culture. Dihydro folate reductase (DHFR)-deficient Chinese hamster ovary (CHO) cell line, DG44 was used for the expression of the antibody whole IgG molecule. The DG44 cells were grown at 5% CO₂, 37⁰C in DMEM/F12 (Invitrogen) supplemented with HT supplement (Invitrogen) and 10% fetal bovine serum (FBS, Invitrogen). For the selection of the dhfr+/neo+ transformants, the transfected DG44 cells were grown in nucleoside-minus MEM-α (Invitrogen) supplemented with 10% dialyzed heat-inactivated FBS (Invitrogen) and G418 (550 μg/mL, Invitrogen).

[0152] Transfection, selection and amplification. 10 μg of IgG expression plasmid for IgG5 antibody (pdCMV-dhfrC-IgG5) was introduced into DG44 using 20 μL of lipofectamin (Invitrogen) according to the protocol suggested by the supplier. Subsequently, dhfr⁺/neo^r clones were selected in α-MEM containing 10% dialyzed FBS and G418. The culture supernatant of survived cell clones was screened for the assembled IgG expression by an indirect ELISA. Several high producer clones were subjected to stepwise dhfr-mediated gene amplification in the presence of increasing level (0.02, 0.1, 0.5 μM) of methotrexate (MTX, Sigma). The productivity of the selected cells was determined by sandwich ELISA using polyclonal anti-human IgG at each MTX level.

[0153] ELISA. The secreted IgG5 antibody in the supernatant was quantified using an ELISA. Goat anti-human IgG (Sigma) was used to coat the microtiter plate wells. Purified human antibody was used as a standard. Peroxidase-labeled goat anti-human IgG (F_c specific, Pierce) was used as an enzyme antibody conjugate. Color was developed with Peroxidase Substrate (TMB, Pierce), and the absorbance of developed color was measured at 450 nm using a microtiter plate reader (Emax, Molecular Devices). [0154] Purification ofIgG5. For purification of IgG, a MTX-selected high producer cell line was plated in a TripleFlask (Nalgen Nunc) at the density of 5^χ10⁴ cells/cm². After 3 days, the culture medium was replaced with a serum-free medium, CHO-SFM II (Invitrogen). The cells were refed with fresh serum-free medium every 3 days. The collected culture supernatant was subjected to affinity chromatography on Protein G-Sepharose column (Amersham Pharmacia Biotech) pre-equilibrated with 0.2 M sodium phosphate buffer (pH 7.0). The bound antibody was eluted with 50 mM Triethyleneamine. The eluate was immediately neutralized with 1 M phosphate buffer (pH 7.0) and dialyzed against PBS (pH 7.0). For the quantification of the purified antibody, the optical density of 1.43 at 280 nm was taken for the protein concentration of 1 mg/ml.

EXAMPLE 3

Construction and Expression of scFv5-Fc

[0155] Construction of the scFv5-Fc gene. The construction strategy is outlined in Figure 1. The DNA sequences encoding the C_H2-C_H3 domains was amplified from the IgG expression vector using the primers Hind-Sfi-Fc for: 5' CCC AAG CTT GGG GGC CTC GGGGGC CTG TGC CCA CCG TGC CCA GCA CCT G and Xho-stop-Fcrev: 5' CCG CTC GAG CGGTTAGTCACT CAT TAT TTA CCC GGG GAC AGG GAG AGG. The obtained PCR product was gel purified, digested with the restriction enzymes Hindlϊl and Xhol and again purified using PCR purification kit (Qiagen). The mammalian expression vector pSecTag2a was digested with Hindlll and Xhol and the resulting digested vector DNA gel purified. Subsequently, the digested Fc fragment was ligated into the digested pSecTag2a and the ligation product (now called pSecFc) was transformed into XLl -Blue E. coli. On the next day colonies were picked from Luria-Bertain broth agar plates containing carbenicillin (100 μg/mL) and grown in LB broth containing carbenicillin (100 μg/mL) overnight. The cultures were mini- prepped on the next day and the isolated plasmid DNA was analyzed by Hindlϊl/Xhol digest. All 10 clones were shown to contain the Fc fragment by agarose gel analysis. pSecFc was digested with Sfil and gel purified. S/zI-digested scFv5 DNA was ligated into the digested pSecFc and the ligation product (now called pSecFc-Ab5) was transformed into XLl -Blue E. coli. On the next day colonies were picked from Luria-Bertain broth agar plates containing carbenicillin (100 μg/mL) and grown in LB broth containing carbenicillin (100 μg/mL) overnight. The cultures were mini-prepped on the next day and the isolated plasmid DNA was analyzed by Sfil digest. Clones 3,4,6,9, and 10 were shown to contain the scFv5 band by agarose gel analysis. The sequence of the scFv5-Fc polynucleotide and amino acid sequences containing the Sfi site between the scFv and Fc regions can be found in Figure 19B, SEQ ID NO:49 and SEQ ID NO:50, respectively.

[0156] Transfection, selection and amplification. 1 μg of pSecFc-Ab5 was introduced into CHO-Kl cells using FuGeneβ transfection reagent (Roche) according to the protocol suggested by the supplier. Subsequently, zeocin¹ clones were selected in Ham's F12K containing 10% dialyzed FBS and zeocin. The culture supernatant of selected cell clones was screened for the assembled scFv5-Fc expression by Western blot.

[0157] Western blot analysis. The secreted scFv5-Fc antibody in the supernatant was detected using Western blot analysis. The supernatant samples were denatured either in the presence or absence of the reducing agent TCEPΗC1 (Tris[2-carboxyethyl]phosphine hydrochloride) at 100 ⁰C for 10 minutes, cooled on ice, and spun down for 10 minutes at 13000 rpm. The samples were separated using SDS-PAGE and transferred onto nitrocellulose membranes. The membranes were blocked using 2% skim milk in Tris-buffered saline (TBS) and 0.01% Tween 20 for 15 minutes and thoroughly washed with TBS/Tween20 3 times for 5 minutes each. Anti-human IgG (recognizing the Fc portion)-horseradish peroxidase (HRP) conjugates in blocking was used to detect scFv5-Fc protein on the membrane. The Western blot was developed using SuperSignal WestFemto substrate (Pierce). The chemiluminescence was detected using FluoroChem 8900.

[0158] Large scale expression and purification ofscFv5-Fc. pSecFc-Ab5 was introduced into CHO-Kl cells and several parental cell clones producing high level of functional Ab5 antibody were selected using zeocin (0.8 mg/mL). Selected high producer clones had scFv5- Fc production (qAb) as high as 1 mg / 2 x 10⁷ cells/week. The selected clones were initially amplified in 10% FBS supplemented RPMI 1640 in 150 cm² cell culture flasks (Corning, USA). The clones were further amplified in 15% Ultra low IgG FBS(Invitrogen, USA) and 4 mM GlutaMax(Invitrogen, USA) supplemented RPMI 1640 and transferred into a AD- 1000 bioreactor flask (Integra Biosciences, UK) at a cell density of 1.0 x 10⁶/mL and incubated at 37 ⁰C in 5% CO₂ incubator. The cells were harvested after 7-10 days following the ADlOOO Integra Biosciences protocol provided by the manufacturer. The scFv5-Fc protein was purified from the culture supernatant by affinity chromatography on a Protein A column. The purity and integrity of the purified antibodies were confirmed by SDS-PAGE analysis, which showed more than 95% purity of scFv5-Fc. About 1 mg of purified scFv5-Fc antibody was obtained from 20 mL of culture supernatant. EXAMPLE 4

Evaluation of Binding of scFv5-Fc to Metastatic Cancer Cells Expressing Integrin α_vβ₃

[0159] Whole cell ELISA. Integrin α_vβ₃-expressing cancer cells, e.g. Mel21, were seeded in a 96-well plate in serum-free RPMI medium at 90% confluency and allowed to adhere at 37 ⁰C for 6 h. Then, the cells were washed with binding buffer (Tris-buffered saline with 1 mM Ca²⁺, 1 mM Mg²⁺, and 0.2 mM Mn²⁺) once, incubated in blocking buffer (Tris-buffered saline with 1 mM Ca²⁺, 1 mM Mg²⁺, 0.2 mM Mn²⁺ and 5% skim milk) at 37 ⁰C for 1 h. and again washed with binding buffer. The antibodies (in blocking buffer) were added to the wells in appropriate amounts in 100 μl volume. The plate was incubated at 37 ⁰C for 1 h with gentle agitation. Afterwards, the wells were washed 10 times with binding buffer. 100 μl of the appropriate secondary antibody (anti-FLAG-HRP conjugate or anti-human Fc-HRP conjugate) in blocking buffer was added to each well and incubated at room temperature for 1 h. The plate was washed again 10 times with washing buffer and 100 μl of HRP substrate were added to each well. To stop the reaction lOOμl 2M H₂SO₄ were added into each well and the absorbance at a wavelength of 450 nm was read using microtiter plate reader (Emax, Molecular Devices).

[0160] Flow Cytometry. The antibodies were analyzed by flow cytometry for binding to integrin α_vβ₃ on human tumor cells and their ability to distinguish between the activated and non-activated form of the receptor. The clones were tested on cells that express α_vβ3 or lack this receptor but express α_v or β₃ in combination with other integrin subunits: M21 melanoma cells (α_vβ3, no other β₃ integrin), M21-L (no α_v integrins), M21-LIIb (αllbβ3, no α_v integrins), and UCLA-P3 lung adenocarcinoma (α_v integrins but no α_vβ3). All of these cells express a variety of other integrins, including βi integrins. For our study, 2 x 10⁵ tumor cells were blocked with goat serum and incubated either with scFv phage (2-5 x 10¹⁰), followed by mouse anti-M13 mAb and goat FITC-anti-mouse or with purified scFv (15 μg/ml), followed by mouse anti-FLAG mAb M2 and goat FITC-anti-mouse antibodies. For the detection of scFv5-Fc protein, an anti-human Fc antibody-FITC conjugate was used. Binding/washing buffer was Tris-buffered saline with or without 1 mM Ca²⁺, 1 mM Mg²⁺, or 0.2 mM Mn²⁺.

EXAMPLE 5

Flow Cytometric Analysis of Binding to Integrin α_vβ₃

[0161] Analysis of binding ofFab5-phage to M21 cancer cells. Fab5 phage were purified and evaluated for their ability to bind to Integrin α_vβ₃-expressing M21 cancer cells using whole cell ELISA. This analysis revealed that Fab5 -phage possessed poor antigen binding compared to scFv5 -phage (Figure 2).

[0162] Flow cytometric analysis of binding of purified Fab5 to M21 cancer cells. Fab5 and scFv5 proteins were purified and evaluated for their ability to bind to Integrin α_vβ3- expressing M21 cancer cells using flow cytometry. This analysis revealed that Fab5 possessed poor antigen binding compared to scFv5 (Figure 3).

[0163] Expression and purification ofIgG5. After pdCMV-dhfrC-IgG5 was introduced into DG44, several parental cell clones producing high level of functional Ab5 antibody were selected and subjected to successive rounds of MTX selection. Antibody productivity of each cell clone usually increased as MTX level went up. Finally, the stepwise gene amplification procedure generated several high producer cell clones with specific antibody productivity (^Ab) as high as 8 μg/10⁶ cells/day.

[0164] One of the high producer clones was cultivated in a serum- free medium. IgG5 antibody was purified from the culture supernatant by affinity chromatography on a Protein G column. The purity and integrity of the purified antibodies were confirmed by SDS-PAGE analysis, which showed more than 95% purity of IgG. About 8 mg of purified IgG5 antibody could be obtained from 900 ml of culture supernatant.

[0165] Analysis of binding of purified IgG 5 to M21 cancer cells. IgG5 protein and scFv5 proteins were purified and evaluated for their ability to bind to Integrin α_vβ3-expressing M21 cancer cells using whole cell ELISA. This analysis revealed that IgG5 a slightly worse antigen binding compared to scFv5 (Figure 4).

[0166] Expression and purification ofscFv5-Fc. After pSecFc-Ab5 was introduced into CHO-Kl cells, several parental cell clones producing high level of functional Ab5 antibody were selected and subjected to successive rounds of zeocin selection. Finally, the stepwise gene amplification procedure generated several high producer cell clones with specific antibody productivity (^_Ab) as high as 8 μg/10⁶ cells/day. Western blot analysis revealed that the produced scFv5-Fc had the expected size of 100 kD in its dimerized form and 50 kD under reducing conditions as a monomer (Figure 5).

[0167] One of the high producer clones was cultivated in a serum- free medium. The scFv5-Fc protein was purified from the culture supernatant by affinity chromatography on a Protein A column. The purity and integrity of the purified antibodies were confirmed by SDS- PAGE analysis, which showed more than 95% purity of scFv5-Fc. About 1 mg of purified scFv5-Fc antibody was be obtained from 30 ml of culture supernatant. SDS-PAGE analysis under reducing conditions showed the expected presence of a 50 kD protein band (Figure 6). [0168] Binding ofscFv5-Fc to SJSA-I cancer cells. The purified scFv5-Fc protein was tested for its ability to bind SJSA-I cells under flow cytometirc conditions. Purified scFv5 was used as positive control, its inactive mutant Mut5 (RGD->RGE) was used as negative control in these experiments. The data show that scFv5-Fc possesses excellent binding ability to SJSA-I cells whereas scFv5 shows only moderate binding and Mut5 exhibit only extremely weak binding to the cells (Figure 7).

[0169] Flow cytometric analysis of the metal ion-dependent binding ofscFv5-Fc to SJSA-I cancer cells. The purified scFv5-Fc protein was tested for its ability to bind SJSA-I cells under flow cytometirc conditions in a metal ion-dependent fashion. One of the hallmarks of scFv5 is its dependence on bivalent metal cations as a prerequisite for the binding to α_vβ3 integrins. Felding-Habermann, et al, Proc Natl Acad Sci U SA, 101: 17210-17215, 2004. Here we investigate and confirm that scFv5-Fc still possesses this metal ion-dependent binding phenomenon (Figure 8).

[0170] Results of experiments demonstrated that scFv5-IgG5 does not bind to integrin- positive cells, whereas scFv5-Fc does bind to integrin-positive cells. Figure 9 shows an analysis of the abilities of scFv5, Mut5, scFv5-IgG5, and control IgG to bind to BCM2 cancer cells. These data show that IgG5 is not able to bind to integrin αvβ3-expressing BCM2 cells, while scFv5 recognizes these cells. The absolute values of mean fluorescence intensities of scFv5 and IgG5 cannot be compared as different secondary antibodies for the detection of scFv5 and IgG5 were used. Rather scFv5 and Mut5 as well as IgG5 and IgG CP48 should be compared. Figure 10 shows an analysis of the ability of scFv5-Fc to bind to BCM2 and SJSA-I cancer cells. These data show that scFv5-Fc is able to bind to integrin αvβ3 -expressing cancer cells in a bivalent metal-dependent manner.

[0171] Additional experiments were conducted to directly compare the ability of scFv5- Fc and scFv5-IgG5 to bind to SJSA-I cells and the dependency of binding on bivalent cations. SJSA-I cells were grown in supplemented RPMI 1640 medium, harvested with Versene (Gibco), washed thoroughly with Calcium- and Magnesium-depleted PBS (Gibco), and counted. For incubation with antibodies, cells were resuspended in TBS, TBS containing Ca²⁺ (2 mM) and TBS containing Mn²⁺ (0.1 mM) at a concentration of 106 cells/ml in 500 μl volume. Cells were then incubated with primary antibodies (1 :200) for one hour on ice, followed by a washing step and incubation with secondary antibody (1 : 100). Secondary antibody was Immunopure Rabbit Anti human Fc FITC conjugated Ab (Thermo Scientific). Prior to analysis, PI (Molecular Probes) was added to all samples for exclusion of dead cells. All measurements were carried out on a LSR-II, Becton Dickinson at the TSRI Flow core. Data was analyzed using the Flow Jo™ flow cytometric analysis software (Treestar).

[0172] The data (Table 1) demonstrate that the fully human scFv5 (IgG5) has lost its ability to recognize and bind to the integrin αvβ3-positive SJSA-I osteosarcoma cells. In contrast, scFv5-Fc displayed bivalent Mn²⁺ cation-dependent binding to SJSA-I cells. In the presence Of Mn²⁺ cations, which induce the "activated" conformation of integrin αvβ3, scFv5-Fc displayed strong binding, indicating that it recognizes the activated form of the integrin (conformational epitope). The addition of Ca²⁺ cation did not facilitate or induce binding of either antibody construct, indicating that only the activated form of integrin αvβ3 is recognized by scFv5-Fc.

Table 1 - Binding of scFv5-Fc and IgG5 to αvβ3-positive osteosarcoma cells in the presence and absence of bivalent cations.

Sample Geo.Mean

Standard TBS

1. SJSA-I TBS 12

2. SJSA-I TBS with 2nd antibody 35.9

3. SJSA-I TBS with IgG5 54.3

4. SJSA-I TBS with scFv5-Fc 57

Manganese

5. SJSA-I TBS + Manganese 16.1

6. SJSA- 1 TB S + Manganese with 2nd antibody 61.6

7. SJSA-I TBS + Manganese with IgG5 52.7

8. SJSA-I TBS + Manganese with scFv5-Fc 140

Calcium

9. SJSA-I TBS + Calcium 15.1

10. SJSA- 1 TBS + Calcium with 2nd antibody 47

11. SJSA-I TBS +Calcium with IgG5 52.6

12. SJSA-I TBS + Calcium with scFv5-Fc 59

[0173] Thus, addition of the Fc region to the scFv provides improved pharmacokinetic properties, for example, improved serum half life, improved complement fixation, and increased ability to mediate cytotoxicity. Fc region variants of IgGl, IgG2, IgG3, or IgG4 are provided herein with further improved pharmacokinetic properties. [0174] Figure 11 shows the scFv5 amino acid sequence (SEQ ID NO:1) and the scFvl amino acid sequence (SEQ ID N0:2).

[0175] Figure 12 shows the scFv5-Fc nucleic acid sequence (SEQ ID NO:3) and the scFv5-Fc amino acid sequence (SEQ ID N0:4) which have improved pharmacokinetic activity.

[0176] Figure 13 shows the scFvl-Fc nucleic acid sequence (SEQ ID NO:5) and the scFvl-Fc amino acid sequence (SEQ ID NO: 6).

[0177] Figures 14A, 14B, 14C, 14D, and 14E show the scFv5-Fc/ variant IgGl nucleic acid sequence and the scFv5-Fc/ variant IgGl amino acid sequence (SEQ ID NO:7 to 16). The Fc region variants are derived from the Fc region of IgGl as marked in bold underline.

[0178] Figures 15A, 15B, 15C, 15D, and 15E show the scFvl-Fc/ variant IgGl nucleic acid sequence and the scFvl-Fc/ variant IgGl amino acid sequence (SEQ ID NO: 17 to 26). The Fc region variants are derived from the Fc region of IgGl as marked in bold underline.

[0179] Figures 16A, 16B, 16C, and 16D show the scFv5 -Fc/ variant IgGl nucleic acid sequence and the scFv5-Fc/ variant IgGl amino acid sequence (SEQ ID NO:27 to 34). The Fc region variants are derived from the Fc regions of IgGl, IgG2, IgG3, or IgG4.

[0180] Figures 17A, 17B, 17C, and 17D show the scFvl -Fc/ variant IgGl nucleic acid sequence and the scFvl-Fc/ variant IgGl amino acid sequence (SEQ ID NO:35-42). The Fc region variants are derived from the Fc regions of IgGl, IgG2, IgG3, or IgG4.

[0181] Figures 18A and 18B show the scFvl-Fc/ variant IgGl nucleic acid sequence and the scFvl-Fc/IgGl amino acid sequence (SEQ ID NO:43 to 46). The Fc region variants are derived from the Fc region of IgGl. Hinton PR, et al, J. Immunol. 176: 346-356, 2006

[0182] Figures 19A and 19B shows the scFv5-Fc/ variant IgGl nucleic acid sequence and the scFv5-Fc/ variant IgGl amino acid sequence (SEQ ID NO:47 to 50). The Fc region variants are derived from the Fc region of IgGl.

[0183] All publications and patent applications cited in this specification are herein incorporated by reference in their entirety for all purposes as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference for all purposes.

[0184] Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it will be readily apparent to one of ordinary skill in the art in light of the teachings of this invention that certain changes and modifications may be made thereto without departing from the spirit or scope of the appended claims.

Claims

What is Claimed:

1. An isolated scFv-Fc fusion antibody which specifically binds to an activated αvβ3 integrin receptor which is differentially produced on a cell in a metastatic state compared to a similar, non-metastatic cell, said antibody comprising an amino acid sequence of SEQ ID NO: 1 and an Fc constant region covalently bound to the carboxy terminus of SEQ ID NO: 1.

2. The isolated antibody of claim 1 wherein the Fc constant region is an IgGl, IgG2, IgG3, or IgG4 constant region.

3. The isolated antibody of claim 1 wherein the Fc constant region is an IgGl constant region.

4. The antibody of claim 1, wherein said metastatic cell targets to a tissue selected from breast, brain, lung, liver, or bone.

5. The antibody of claim 1 , wherein the antibody is a ligand mimetic.

6. The antibody of claim 1, wherein the scFv-Fc fusion antibody comprises an amino acid sequence of SEQ ID NO: 4.

7. The antibody of claim 1, wherein the scFv-Fc fusion antibody comprises an amino acid sequence of SEQ ID NO: 50.

8. A pharmaceutical composition comprising an isolated scFv-Fc fusion antibody which specifically binds to an activated αvβ3 integrin receptor which is differentially produced on a cell in a metastatic state compared to a similar, non-metastatic cell, said antibody comprising an amino acid sequence of SEQ ID NO: 1 and an Fc constant region covalently bound to the carboxy terminus of SEQ ID NO: 1.

9. The pharmaceutical composition of claim 8, wherein the scFv-Fc fusion antibody comprises an amino acid sequence of SEQ ID NO: 4.

10. An isolated polynucleotide encoding an scFv-Fc fusion antibody, said polynucleotide comprising a nucleotide sequence that has at least 90% identity to SEQ ID NO: 3.

11. An isolated polypeptide comprising an amino acid sequence that has at least 90% sequence identity to SEQ ID NO: 4, wherein the polypeptide specifically binds to an activated αvβ3 integrin receptor which is differentially produced on a cell in a metastatic state compared to a similar, non-metastatic cell.

12. A vector comprising the polynucleotide of claim 10.

13. An expression vector comprising the polynucleotide of claim 10 in which the nucleotide sequence of the polynucleotide is operatively linked with a regulatory sequence that controls expression of the polynucleotide in a host cell.

14. A host cell comprising the expression vector of claim 13, or progeny of the cell.

15. An isolated scFv-Fc fusion antibody which specifically binds to an activated αvβ3 integrin receptor which is differentially produced on a cell in a metastatic state compared to a similar, non-metastatic cell, said antibody comprising an amino acid sequence of SEQ ID NO: 2 and an Fc constant region covalently bound to the carboxy terminus of SEQ ID NO:2.

16. The isolated antibody of claim 15 wherein the Fc constant region is an IgGl, IgG2, IgG3, or IgG4 constant region.

17. The isolated antibody of claim 15 wherein the Fc constant region is an IgGl constant region.

18. The isolated antibody of claim 15, wherein said metastatic cell targets to a tissue selected from breast, brain, lung, liver, or bone.

19. The isolated antibody of claim 15, wherein the antibody is a ligand mimetic.

20. The isolated antibody of claim 15, wherein the scFv-Fc fusion antibody comprises an amino acid sequence of SEQ ID NO: 6.

21. The isolated antibody of claim 15, wherein the scFv-Fc fusion antibody comprises an amino acid sequence of SEQ ID NO: 48.

22. A pharmaceutical composition comprising an isolated scFv-Fc fusion antibody which specifically binds to an activated αvβ3 integrin receptor which is differentially produced on a cell in a metastatic state compared to a similar, non-metastatic cell, said antibody comprising an amino acid sequence of SEQ ID NO:2 and an Fc constant region covalently bound to the carboxy terminus of SEQ ID NO:2.

23. The pharmaceutical composition of claim 22, wherein the scFv-Fc fusion antibody comprises an amino acid sequence of SEQ ID NO: 6.

24. An isolated polynucleotide encoding an scFv-Fc fusion antibody, said polynucleotide comprising a nucleotide sequence that has at least 90% identity to SEQ ID NO: 5.

25. An isolated scFv-Fc antibody comprising an amino acid sequence that has at least 90% sequence identity to SEQ ID NO: 6, which specifically binds to an activated αvβ3 integrin receptor which is differentially produced on a cell in a metastatic state compared to a similar, non-metastatic cell.

26. A vector comprising the polynucleotide of claim 24.

27. An expression vector comprising the polynucleotide of claim 24 in which the nucleotide sequence of the polynucleotide is operatively linked with a regulatory sequence that controls expression of the polynucleotide in a host cell.

28. A host cell comprising the expression vector of claim 27, or progeny of the cell.

29. A method for treating cancer in a mammal comprising administering to the mammal an isolated scFv-Fc fusion antibody which specifically binds to an activated αvβ3 integrin receptor which is differentially produced on a cell in a metastatic state as compared to a non-metastatic cell, said antibody comprising an amino acid sequence of SEQ ID NO: 1 and an Fc constant region covalently bound to the carboxy terminus of SEQ ID NO: 1.

30. The method of claim 29, wherein the scFv-Fc fusion antibody comprises an amino acid sequence of SEQ ID NO: 4.

31. The method of claim 29, wherein the cancer is solid tumor, hematological malignancy, leukemia, colorectal cancer, benign or malignant breast cancer, uterine cancer, uterine leiomyomas, ovarian cancer, endometrial cancer, polycystic ovary syndrome, endometrial polyps, prostate cancer, prostatic hypertrophy, pituitary cancer, adenomyosis, adenocarcinomas, meningioma, melanoma, bone cancer, multiple myeloma, CNS cancer, glioma, or astroblastoma.

32. The method of claim 31 , wherein the cancer is breast cancer metastasis in said mammal.

33. A method for treating cancer in a mammal comprising administering to the mammal an isolated scFv-Fc fusion antibody which specifically binds to an activated αvβ3 integrin receptor which is differentially produced on a cell in a metastatic state as compared to a non-metastatic cell, said antibody comprising an amino acid sequence of SEQ ID NO: 2 and an Fc constant region covalently bound to the carboxy terminus of SEQ ID NO:2.

34. The method of claim 33, wherein the scFv-Fc fusion antibody comprises an amino acid sequence of SEQ ID NO: 6.

35. The method of claim 33, wherein the cancer is solid tumor, hematological malignancy, leukemia, colorectal cancer, benign or malignant breast cancer, uterine cancer, uterine leiomyomas, ovarian cancer, endometrial cancer, polycystic ovary syndrome, endometrial polyps, prostate cancer, prostatic hypertrophy, pituitary cancer, adenomyosis, adenocarcinomas, meningioma, melanoma, bone cancer, multiple myeloma, CNS cancer, glioma, or astroblastoma.

36. The method of claim 35, wherein the cancer is breast cancer metastasis in said mammal.