Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K16/00—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies
  • C07K16/18—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies against material from animals or humans
  • C07K16/28—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies against material from animals or humans against receptors, cell surface antigens or cell surface determinants
  • C07K16/2863—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies against material from animals or humans against receptors, cell surface antigens or cell surface determinants against receptors for growth factors, growth regulators
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P35/00—Antineoplastic agents
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P43/00—Drugs for specific purposes, not provided for in groups A61P1/00-A61P41/00
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K39/00—Medicinal preparations containing antigens or antibodies
  • A61K2039/505—Medicinal preparations containing antigens or antibodies comprising antibodies
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K2317/00—Immunoglobulins specific features
  • C07K2317/30—Immunoglobulins specific features characterized by aspects of specificity or valency
  • C07K2317/31—Immunoglobulins specific features characterized by aspects of specificity or valency multispecific
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K2317/00—Immunoglobulins specific features
  • C07K2317/60—Immunoglobulins specific features characterized by non-natural combinations of immunoglobulin fragments
  • C07K2317/62—Immunoglobulins specific features characterized by non-natural combinations of immunoglobulin fragments comprising only variable region components
  • C07K2317/622—Single chain antibody (scFv)
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K2317/00—Immunoglobulins specific features
  • C07K2317/60—Immunoglobulins specific features characterized by non-natural combinations of immunoglobulin fragments
  • C07K2317/62—Immunoglobulins specific features characterized by non-natural combinations of immunoglobulin fragments comprising only variable region components
  • C07K2317/626—Diabody or triabody
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K2317/00—Immunoglobulins specific features
  • C07K2317/70—Immunoglobulins specific features characterized by effect upon binding to a cell or to an antigen
  • C07K2317/73—Inducing cell death, e.g. apoptosis, necrosis or inhibition of cell proliferation
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K2317/00—Immunoglobulins specific features
  • C07K2317/70—Immunoglobulins specific features characterized by effect upon binding to a cell or to an antigen
  • C07K2317/73—Inducing cell death, e.g. apoptosis, necrosis or inhibition of cell proliferation
  • C07K2317/732—Antibody-dependent cellular cytotoxicity [ADCC]
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K2317/00—Immunoglobulins specific features
  • C07K2317/70—Immunoglobulins specific features characterized by effect upon binding to a cell or to an antigen
  • C07K2317/77—Internalization into the cell
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K2317/00—Immunoglobulins specific features
  • C07K2317/90—Immunoglobulins specific features characterized by (pharmaco)kinetic aspects or by stability of the immunoglobulin
  • C07K2317/92—Affinity (KD), association rate (Ka), dissociation rate (Kd) or EC50 value

Definitions

• the present invention is directed to novel tetravalent antibodies, which are preferably bi-specific.
• the tetravalent bispecific antibodies can be efficiently expressed in prokaryotic and eukaryotic cells, and are useful in therapeutic and diagnostic methods.
• the invention further relates to combination therapies using the antibodies with anti-angiogenic or anti-neoplastic drugs.
• Bispecific antibodies are immunoglobulin (Ig)-based molecules that bind to two different epitopes on either the same or distinct antigens. Both laboratory and early clinical studies have demonstrated that BsAb may have significant applications in cancer therapy by either targeting tumor cells with cytotoxic agents such as effector cells, radionuclides, drugs and toxins (Weiner et al. (1997) Cancer Immunol. Immunother. 45:190- 2.; van Spriel et al. (2000) Immuol. Today 21:391-7; Segal et al. (2000) J. Immunol.
• a diabody is a form of scFv dimer which is constructed with a short linker (5- 10 amino acid residues) between the variable heavy (VH) and the variable light (VL) domains.
• the short linker prevents intrachain pairing of VH and the VL domains, but allows interchain pairing of VH and the VL domains, such that a bivalent antibody fragment with a molecular size of approximately 55 to 60 kDa is formed.
• a bispecific diabody can be produced by coexpression of two "cross-over" scFv fragments in which the VH and the VL domains for
• NYOl 924757 vl each of the two binding sites are present on different polypeptide chains (Holliger et al. (1993); Zhu et al. (1996)). Interchain pairing of the two "cross-over" polypeptide chains results in the formation of a scFv dimer, or bispecific diabody, which is a divalent antibody molecule that is monovalent for each of its target antigens.
• the invention provides a novel tetravalent bispecific antibody (BsAb) molecule.
• the BsAb comprises two identical diabodies (DAB), each having two antibody binding sites, preferably non-identical.
• DAB diabodies
• One of the diabody chains includes an immunoglobulin hinge region and at least one heavy chain constant domain that is capable of self-association to form a dimer (e.g., a C H 2 and/or a C R 3 domain).
• Di-diabodies offer several advantages as compared to previously described (BsAbs). Di-diabodies can be produced that are bispecific and bivalent. Di-diabodies have no constraints regarding selection of antigen-binding sites, and Fc constant domains and associated functions can be retained. The proteins are substantially homogeneous and can be produced bacterial, mammalian, or other cells without further processing.
• bispecific di-diabodies for each of two different antigens are comparable to those of natural antibodies (i.e., full, monospecific divalent IgG molecules naturally produced by a host) for each antigen
• a single pharmaceutical di-diabody preparation can be used in place of a combination of two monospecific antibodies.
• the di-diabodies can also be monospecific (i.e., four identical antibody binding sites).
• the di-diabodies of the invention are efficiently produced in mammalian cells, and can be purified by conventional protein A chromatography in a single step.
• Di-diabodies of the invention comprise at least one IgG constant domain that is capable of self association, such as, for example, C H 2 or CH3 of IgG, IgA, or IgD, or C H 2, CH3, or CR4 of IgE or IgM. Accordingly, di-diabodies possess the immunological functions associated with such domains that are present, such as Fc receptor binding, complement mediated cytotoxicity (CMC), or antibody dependent cell-mediated cytoxicity (ADCC).
• CMC complement mediated cytotoxicity
• ADCC antibody dependent cell-mediated cytoxicity
• di-diabodies of the invention bind to and block activation of a growth factor receptor such as, but not limited to, VEGFR-I, VEGFR-2,
• the di-diabodies bind to and block activation of two such receptors, hi other embodiments, di-diabodies are capable of simultaneous binding to a growth factor receptor on a target cell, and to a cell surface antigen of an immune system effector cell.
• Di-diabodies of the invention are used to neutralize growth factor receptors, and to reduce tumor growth and/or inhibit angiogenesis associated with activation of such receptors. Further, the di-diabodies can be administered with anti-neoplastic agents such as chemotherapeutic agents or radiation.
• Figure 1 is a schematic diagram depicting expression constructs for various antibody fragments, hi the di-diabody, the first of two scFv polypeptide chains was fused to an IgG hinge region and C H 3 domain.
• a diabody results from association of the first and second scFv chains.
• a tetrameric structure is formed by two diabodies associated by the hinge and C H 3 domains.
• G 4 S a 5 amino-acid linker "GGGGS”.
• E the 13 amino-acid E-tag.
• Figure 2 shows SDS-PAGE analysis of the purified antibody fragments.
• Panel A non-reducing conditions
• Panel B reducing conditions
• lane 1 diabody (DAB) pi CIl
• lane 2 DAB 612
• lane 3 DAB plCl 1/612
• lane 4 Di-diabody (B); lane 5, di-diabody (M).
• molecular weight standards run under non-reducing conditions (from top to bottom: 176.5, 113.7, 80.9, 63.8, 49.5, 37.4, 28.0, and 19.6 kDa, respectively).
• Figure 3 shows bispecific and dose-dependent binding of a di-diabody specific for KDR and FIt-I .
• Top panel cross-linking assay using FIt-I -coated support and soluble KDR-AP.
• Middle and bottom panels various concentrations of antibody fragments were bound to a KDR or FIt-I coated support, then incubated with a secondary HRP conjugated reagent. Following incubation with a peroxidase, OD450nm was read. Data shown represent the mean ⁇ SD of triplicate samples.
• Figure 4 shows inhibition of binding of KDR and FIt-I to immobilized VEGF by the bispecific antibody fragments.
• Various concentrations of antibody fragments were incubated with a fixed amount of KDR-AP or FIt-I -AP fusion proteins.
• Bound KDR-AP or Flt-l-AP was quantified by incubation with a peroxidase substrate and OD405nm measurement. Data shown represent the mean ⁇ SD of triplicate samples.
• Figure 5 shows inhibition of VEGF-induced migration of human leukemia cells by the bispecific antibody fragments.
• HEL or U937 cells on supports were incubated with various concentrations of antibodies, then placed into wells containing VEGF. Migrated cells were collected and counted. Data shown are the mean ⁇ SD of triplicate determinations.
• Figure 6 shows the stability of di-diabody preparations incubated in PBS or mouse serum.
• the di-diabodies were incubated with PBS or serum at 37 0 C for up to 72 hours.
• Data are expressed as percentage of antigen binding activity of each antibody preparation retained after 37°C incubation in comparison to that of samples incubated at 4 0 C in PBS.
• Data shown represent the mean ⁇ SD of triplicate samples.
• Figure 7 depicts construction and production of a di-diabody having binding sites specific for EGFR and IGFR.
• Panels (A) and (B) are schematic diagrams showing the expression constructs.
• L Linker (Arg-Thr-Val-Ala-Ala); H: IgGl hinge region.
• Purified di- diabody preparations were analyzed by SDS-PAGE under non-reducing (C) or reducing (D) conditions.
• Lane 1 IMC-11F8 IgG
• lane 2 the di-diabody.
• Also shown on the left side are molecular weight standards.
• Figure 8 shows bispecific and dose-dependent binding of the EGFR x IGFR di-diabody.
• A Receptor cross-linking assay. Antibody preparations were first incubated with a biotin-labeled IGFR in solution and then transferred to a microtiter plate coated with EGFR, followed by incubation with streptoavidin-HRP to measure the plate-bound biotin activity.
• B and
• C Dose-dependent binding of the di-diabody to immobilized EGFR and IGFR.
• Figure 9 shows antiproliferative activity of the EGFR x IGFR di-diabody.
• Various amounts of the antibodies were incubated with DiFi cells in culture for 4 days followed by incubation with MTT for 4 h. The plates were washed and incubated with HCl/isopropanol at RT for 10 min, followed by optical density reading at 570nm. Data shown represent the mean ⁇ SD of triplicate samples.
• Figure 10 shows inhibition of EGF and IGF-stimulated activation of receptors and downstream signaling molecules, Akt and MAPK p44/p42. MCF-7 cells were incubated
• FIG 11 shows IGFR internalization and degradation in tumor cells.
• Tumor cells were plated and incubated overnight in serum-free medium.
• IGF-I, EGF (50 nM), IGF plus EGF (I + E) or various antibodies was then added and incubated at 37°C for up to 4 h.
• Cells were washed in ice-cold PBS, lysed, and electrophoresed using 4-12% Tris-Glycine gels. Proteins were transferred to nitrocellulose membranes and were detected by Western blotting using antibody C-20 (rabbit anti-IGFR) and IMC-11F8 (human anti-EGFR), followed by an anti-rabbit or anti-human antibody-HRP conjugate. The signals were visualized with the ECL reagent.
• A The di-diabody induced IGFR degradation in a dose- dependent manner in MCF-7 cells.
• B The di-diabody (100 nM) induced IGFR degradation as efficiently as EVIC-A12 and the combination of IMC-A12 and IMC-11F8 after 4 h incubation at 37°C.
• C The Di-diabody (100 nM) induced IGFR degradation in BxPC3 cells in a time-dependent manner when incubated at 37 0 C.
• DAb the Di-diabody; A + F, IMC-A12 plus IMC-11F8; 1121, the control antibody, MC-1121.
• FIG 12 shows di-diabody mediated ADCC in the presence of human PBMC.
• Tumor cells were incubated in the wells of 96-well plates with IMC-11F8, IMC- A12, the Di-diabody, or a normal human IgG at 37°C for 30 min, followed by addition of PBMC at an effector/tumor cell ratios of 100/1 and incubation at 37°C for an additional 4 h. After centrifugation at 1500 rpm for 10 min, 100 ⁇ l of supernatant was transferred to 96 well flat bottom plates, followed by the addition of 100 ⁇ l/well LDH assay reagent and reading of the absorbance at 490nm. The percentages of specific cell lysis were calculated as described in the Materials and Methods. Data represent the means of triplicate determinations.
• Figure 13 shows inhibition of growth of human tumor xenografts in nude mice by the di-diabody.
• Female athymic nu/nu mice were injected subcutaneously on the lateral dorsal surface with BxPC3 (2 x 10 6 /mouse) or HT-29 (5 x 10 6 /mouse) tumor cells.
• NYOl 924757 vl tumors reached approximately 200-300 mm 3 mice were randomized by tumor size and divided into treatment groups. The mice were treated by IMC-11F8 (or the equivalent IMC- C225), IMC-A12, IMC-11F8 (or IMC-C225) plus IMC-A12, the di-diabody, or the control articles (saline or normal human IgG). Each antibody was administered by intraperitoneal injections at 40 mg/kg twice a week. Tumor volume and body weight of each animal was measured twice a week. Data represent the mean ⁇ SE of tumor sizes from 10 to 12 animals in each group.
• the invention provides an antigen-binding protein which is a tetravalent BsAb molecule, comprising two identical diabodies.
• Each diabody is a heterodimer of two polypeptide chains and is preferably bispecific.
• one of the polypeptides of the diabody is fused, via a hinge region, to the N-terminus of an immunoglobulin constant domain that is capable of stable self association (e.g., C H 2 and/or C R 3 if IgGl).
• di-diabody Coexpression of the two polypeptide chains in a single host results in the formation of bispecific diabody-constant domain fusion, which in turn dimerizes via both the hinge and the constant domain to form a bispecific tetravalent protein (a "di-diabody").
• the di-diabody can be efficiently expressed in E.coli and mammalian cells, and is more efficient in binding to its targets and in blocking target-associated biological activities than the corresponding diabody.
• Antibody specificity refers to selective recognition of the antibody for a particular epitope of an antigen. Natural antibodies, for example, are monospecific. Bispecific antibodies (BsAbs) are antibodies which have two different antigen-binding specificities or sites. Where an antigen-binding protein has more than one specificity, the recognized epitopes may be associated with a single antigen or with more than one antigen.
• a natural antibody molecule is composed of two identical heavy chains and two identical light chains. Each light chain is covalently linked to a heavy chain by an interchain disulfide bond. The two heavy chains are further linked to one another by multiple disulfide bonds at the hinge region. The individual chains fold into domains having similar sizes (about 110-125 amino acids) and structures, but different functions.
• the light chain comprises one variable domain (V L ) and one constant domain (C L ).
• V L variable domain
• C L constant domain
• NYOl 9247 5 7 vl comprises one variable domain (V H ) and, depending on the class or isotype of antibody, three or four constant domains (C H I, C H 2, C H 3 and C H 4).
• V H variable domain
• C H I constant domains
• the isotypes are IgA, IgD, IgE, IgG, and IgM, with IgA and IgG further subdivided into subclasses or subtypes.
• the portion of an antibody consisting of V L and V H domains is designated "Fv" and constitutes the antigen-binding site.
• a single chain Fv is an engineered protein containing a VL domain and a V H domain on one polypeptide chain, wherein the N terminus of one domain and the C terminus of the other domain are joined by a flexible linker.
• Fab refers to the portion of the antibody consisting of V L , V H , C L and C H I domains.
• variable domains show considerable amino acid sequence variablity from one antibody to the next, particularly at the location of the antigen binding site.
• Three regions, called “hypervariable” or “complementarity-determining regions” (CDRs) are found in each of V L and V H -
• Fc is the designation for the portion of an antibody which comprises paired heavy chain constant domains, hi an IgG antibody, for example, the Fc comprises C R 2 and CH3 domains.
• the Fc of an IgA or an IgM antibody further comprises a C H 4 domain.
• the Fc is associated with Fc receptor binding, activation of complement-mediated cytotoxicity and antibody-dependent cellular-cytotoxicity.
• complex formation requires Fc constant domains.
• the "hinge” region separates the Fab and Fc portions of the antibody, providing for mobility of Fabs relative to each other and relative to Fc, as well as including multiple disulfide bonds for covalent linkage of the two heavy chains.
• Diabodies contain two polypeptide chains which when associated, form two antibody binding sites.
• Each polypeptide chain contains an immunoglobulin heavy chain variable (V H ) domain and an immunoglobulin light chain variable (V L ) domain, joined by short peptide linker (5-10 amino acids).
• V H immunoglobulin heavy chain variable
• V L immunoglobulin light chain variable
• short peptide linker 5-10 amino acids
• the order of the V H and V L domains of one polypeptide chain is reversed with respect to the other (i.e., V ⁇ -linker-V L and V L -linker-V ⁇ )
• V ⁇ -linker-V L and V L -linker-V ⁇ formation of heterodimers of the two non-identical chains is promoted by the combination of short peptide linkers, which inhibit intrachain V H -VL association, and the order of the variable domains of the two polypeptides. Accordingly, in the heterodimer, VH of the first polypeptide is paired with V
• V H domains are identical and the VL domains are identical
• two heterodimer contains two identical binding sites.
• two different V H domains and two different corresponding VL domains may be employed such that the heterodimer contains two different binding sites and is bispecific (i.e., VB 1 - linker-Vu and V L1 -linker- VH 2 ; see Fig. 1).
• the bispecific di-diabody that results from linking two such bispecific diabodies, is thus bivalent for each of the two different binding sites.
• Di-diabodies of the invention which are bispecific have a combination of desirable features.
• they are essentially homogeneous.
• mispairing of antibody heavy and light chains is greatly reduced or eliminated.
• a typical bispecific antibody requires the use of two different heavy chains to provide two specificities.
• Four combinations are possible when the heavy chains are arranged into an IgG type molecule. Two of those consist of mispaired heavy chains such that the product is monospecific.
• mispairing is substantially eliminated. Pairing of two diabody polypeptides by heterodimerization is favored, and dimerization of the bispecific diabodies is by a different interaction. Accordingly, the products are bispecific.
• a second advantage of the di-diabodies is that they are bivalent for each binding specificity.
• a feature of a natural antibody which is missing from a dimeric BsAb is that the natural antibody is bivalent for the antibody binding site that it comprises.
• a dimeric BsAb is monovalent for each of the two binding sites that it comprises. This is significant for antibody function because bivalency allows for cooperativity of binding and a significant increase in binding avidity with resepect to a molecule comprising a single antigen-binding site.
• a third advantage of the di-diabodies is that heavy chain constant domains which constitute the Fc region (e.g., CH2 and/or C H 3 for an IgGl molecule) of a natural antibody and which provide other antibody functions can be present. Furthermore, the multiple binding domains are separated from the constant domains such that functions provided by the constant domains are not impaired. Constant domain functions include binding to certain accessory molecules (e.g., binding to cell surface and soluble Fc receptors, J chain association for IgA and IgM, S protein for IgA), activation of the complement
• NYOl 924757 vl pathway (complement mediated cytoxicity, CMC), recognition of antibody bound to target cells by several different leukocyte populations (antibody-dependent cell-mediated cytoxicity, ADCC) and opsonization (enhancement of phagocytosis).
• CMC complement mediated cytoxicity
• ADCC antibody-dependent cell-mediated cytoxicity
• opsonization enhancement of phagocytosis
• the Fc heavy chain constant domain(s) can confer increased serum half-life.
• a fourth advantage of proteins of the invention is that there is no requirement for processing in vitro to obtain the complete product. Though rearranged in an artificial manner, each of the domains has a natural character which allows expression in a biological system. For example, di-diabodies can be expressed in prokaryotic and eukaryotic expression systems. The proteins that are produced are substantially bispecific. Although multimeric forms of the bispecific di-diabody may be expressed to some degree (see Examples), these are easily removed from preparations by chromatography if necessary.
• the present invention is also applicable to production of monospecific tetravalent antigen-binding proteins.
• all four binding sites of the di-diabody have the same specificity.
• An antigen binding site for use in a di-diabody can be obtained by a variety of methods.
• the amino acid sequences of the V H and VL portions of a selected binding domain correspond to a naturally-occurring antibody or are chosen or modified to obtained desired immunogenic or binding characteristics.
• V H and V L domains can be obtained directly from a monoclonal antibody which has the desired binding characteristics.
• V H and V L domains can be from libraries of V gene sequences from a mammal of choice. Elements of such libraries express random combinations of V H and V L domains and are screened with any desired antigen to identify those elements which have desired binding characteristics. Particularly preferred is a human V gene library. Methods for such screening are known in the art.
• V H and V L domains from a selected non-human source may be incorporated into chimeric di-diabodies.
• a di-diabody with one or more functional human constant domains wherein the V H and V L domains have been selected from a non-human source.
• human constant domains are preferred.
• a di-diabody can be made that is "humanized.”
• Humanized variable domains are constructed in which amino acid sequences which comprise one or more
• NYOl 9247S7 vl complementarity determining regions (CDRs) of non-human origin are grafted to human framework regions (FRs).
• CDRs complementarity determining regions
• FRs human framework regions
• a humanized construct is particularly valuable for elimination of adverse immunogenic characteristics, for example, where an antigen binding domain from a non-human source is desired to be used for treatment in a human.
• Variable domains have a high degree of structural homology, allowing easy identification of amino acid residues within variable domains which corresponding to CDRs and FRs.
• CDRs are most easily grafted onto different FRs by first amplifying individual FR sequences using overlapping primers which include desired CDR sequences, and joining the resulting gene segments in subsequent amplification reactions. Grafting of a CDR onto a different variable domain can further involve the substitution of amino acid residues which are adjacent to the CDR in the amino acid sequence or packed against the CDR in the folded variable domain structure which affect the conformation of the CDR.
• Humanized variable domains of the invention therefore include human domains which comprise one or more non-human CDRs as well as such domains in which additional substitutions or replacements have been made to preserve or enhance binding characteristics.
• Di-diabodies of the invention may also employ variable domains which have been made less immunogenic by replacing surface-exposed residues to make the di-diabody appear as self to the immune system (Padlan, E.A. (1991) MoI. Immunol. 28, 489-498). Antibodies have been modified by this process with no loss of affinity (Roguska et al. (1994) Proc. Natl. Acad. Sci. USA 91, 969-973). Because the internal packing of amino acid residues in the vicinity of the antigen binding site remains unchanged, affinity is preserved.
• the invention contemplates binding domains which are essentially human.
• Human binding domains are obtained from phage display libraries wherein combinations of human heavy and light chain variable domains are displayed on the surface of filamentous phage (See, e.g., McCafferty et al. (1990) Nature 348, 552-554; Aujame et al. (1997) Human Antibodies 8, 155-168).
• Combinations of variable domains are typically displayed on filamentous phage in the form of Fabs or scFvs.
• the library is screened for phage bearing combinations of variable domains having desired antigen binding characteristics.
• Preferred variable domain combinations display high affinity for a selected antigen and little cross- reactivity to other related antigens.
• human binding domains can be obtained from transgenic animals into which unrearranged human Ig gene segments have been introduced and in which the endogenous mouse Ig genes have been inactivated (reviewed in Bruggemann and Taussig (1997) Curr. Opin. Biotechnol. 8, 455-458).
• Preferred transgenic animals contain very large contiguous Ig gene fragments that are over 1 Mb in size (Mendez et al. (1997) Nature Genet. 15, 146-156) but human Mabs of moderate affinity can be raised from transgenic animals containing smaller gene loci (See, e.g., Wagner et al. (1994) Eur. J. Immunol. 42, 2672-2681; Green et al. (1994) Nature Genet. 7, 13-21).
• binding domains of the invention include those for which binding characteristics have been improved by direct mutation or by methods of affinity maturation. Affinity and specificity may be modified or improved by mutating CDRs and screening for antigen binding sites having the desired characteristics (See, e.g., Yang et al. (1995) J. MoI.
• CDRs are mutated in a variety of ways. One way is to randomize individual residues or combinations of residues so that in a population of otherwise identical antigen binding sites, all twenty amino acids, or a subset thereof, are found at particular positions. Alternatively, mutations are induced over a range of CDR residues by error prone PCR methods (See, e.g., Hawkins et al. (1992) J. MoI. Bio. 226, 889-896). Phage display vectors containing heavy and light chain variable region genes are propagated in mutator strains of E. coli (See, e.g., Low et al. (1996) J. MoI. Bio. 250, 359-368). These methods of mutagenesis are illustrative of the many methods known to one of skill in the art.
• Each variable domain of the antibodies of the present invention may be a complete immunoglobulin heavy or light chain variable domain, or it may be a functional equivalent or a mutant or derivative of a naturally occurring domain, or a synthetic domain constructed, for example, in vitro using a technique such as one described in WO 93/11236 (Medical Research Council / Griffiths et al.). For instance, it is possible to incorporate domains corresponding to antibody variable domains which are missing one or more amino acids.
• the important characterizing feature is the ability of each variable domain to associate with a complementary variable domain to form an antigen binding site.
• Antigen-binding proteins of the invention have binding sites for any epitope, antigenic site or protein.
• di-diabodies that are useful for treatment of disease.
• Preferred di-diabodies neutralize receptor proteins, such as receptors which are involved in angiogenesis and/or oncogenesis.
• Neutralizing a receptor means inactivating the intrinsic kinase activity of the receptor to transduce a signal.
• a reliable assay for receptor neutralization is the inhibition of receptor phosphorylation.
• the present invention is not limited by any particular mechanism of receptor neutralization. Some possible mechanisms include preventing binding of the ligand to the extracellular binding domain of the receptor, and preventing dimerization or oligomerization of receptor. Other mechanisms cannot, however, be ruled out.
• Neutralization of activation of a receptor in a sample of endothelial or non- endothelial cells, such as tumor cells may be performed in vitro or in vivo.
• Neutralizing activation of a receptor in a sample of receptor expressing cells comprises contacting the cells with an antibody of the invention.
• the cells are contacted with the antibody before, simultaneously with, or after, adding VEGF to the cell sample.
• NYOl 9247 5 7 vl invention is contacted with a receptor by administration to a mammal.
• Methods of administration to a mammal include, for example, oral, intravenous, intraperitoneal, subcutaneous, or intramuscular administration.
• VEGF receptors include, but are not limited to VEGF receptors (e.g., VEGFR-2/KDR/Flk-l, VEGFR2/F1M, VEGFR3/Flt-4), epidermal growth factor receptor (EGFR), insulin-like growth factor receptor (IGFR) and the like.
• VEGF receptors e.g., VEGFR-2/KDR/Flk-l, VEGFR2/F1M, VEGFR3/Flt-4
• EGFR epidermal growth factor receptor
• IGFR insulin-like growth factor receptor
• Additional non- limiting examples of receptor tyrosine kinases include Flt-4, HER2/neu, Tek and Tie2.
• FGF fibroblast growth factor
• PDGF platelet derived growth factor
• NGF nerve growth factor
• FGF-R fibroblast growth factor
• PDGF-R platelet derived growth factor receptor
• NGFR nerve growth factor receptor
• MSP-R macrophage-stimulating protein receptor
• Receptors of interest include human proteins and homologues from other mammals.
• Di-diabodies can incorporate immunoglobulin binding domains from any source.
• antibodies are known for the above listed receptors and are sources of V H and V L domains for use in di-diabodies of the present invention.
• binding domains specific for KDR include IMC-ICl 1 (nucleotide and amino acids sequences of V H : SEQ ID NOS:1 and 2; nucleotide and amino acid sequences of V L : SEQ ID NOS:3 and 4) (see, WO 00/44777), EVIC-2C6 (nucleotide and amino acids sequences of V H : SEQ ID NOS: 5 and 6; nucleotide and amino acid sequences of V L : SEQ ID NOS:7 and 8) (see, WO 03/075840), and IMC-1121 (nucleotide and amino acids sequences of V H : SEQ ID NOS: 5 and 6; nucleotide and amino acid sequences of V L :
• binding domains specific for FIt-I include 6.12 (nucleotide and amino acids sequences of V H : SEQ ID NOS: 11 and 12; nucleotide and amino acid sequences of V L : SEQ ID NOS:13 and 14) and BVIC-18F1 (nucleotide and amino acids sequences of V H : SEQ ID NOS :27 and 28; nucleotide and amino acid sequences of V L : SEQ ID NOS :29 and 30).
• Binding domains specific for EGFR include, for example, ERBITUX ® (Cetuximab; IMC-C225) (nucleotide and amino acids sequences of V H : SEQ ID NOS: 15 and 16; nucleotide and amino acid sequences of V L : SEQ ID NOS: 17 and 18) as disclosed in WO
• NYOl 924757 vl 96/40210 and IMCl 1F8 (nucleotide and amino acids sequences of V H : SEQ ID NOS: 19 and 20; nucleotide and amino acid sequences of V L : SEQ ID NOS:21 and 22).
• An example of a binding domain specific for IGFR is IMC-A12 (nucleotide and amino acids sequences of V H : SEQ ID NOS: 23 and 24; nucleotide and amino acid sequences of V L : SEQ ID NOS: 25 and 26).
• Antibodies that bind to FGF receptors include, for example, FR1-H7, FRl-Al, and FRl -4H (WO 2005/037235).
• Antibodies that bind to PDGFR ⁇ include, for example, 3G3 and 7Gl 1 (Loizos et al., 2005, MoI. Cancer Ther. 4:369).
• MSP-R include IMC-41 AlO and IMC-41 A12 (Pereira, International application , filed 13- May-2005).
• binding domains such as the CDR regions
• portions of the above listed binding domains may be incorporated into binding domains used to make the binding proteins described herein.
• Certain preferred diabodies bind to two of the above listed receptors.
• such a bispecific antigen-binding protein binds to KDR and FLT-I.
• An example of such an antigen binding protein has two polypeptide chains as provided in the examples (nucleotide and amino acid sequences: first polypeptide - SEQ ID NOS:51 and 52; second polypeptide - SEQ ID NOS :53 and 54).
• the linkers between the heavy and light chain variable domains are Gly-Gly-Gly-Gly-Ser, but a linker of 0 to 10 amino acids having any amino acid sequence can be used.
• the antigen-binding protein incorporates a C H 3 domain but not a C H 2 domain.
• a linker (Gly-Gly-Gly-Gly-Ser) 2 is incorporated between the hinge region and the IgGl C JJ 3 domain, but a linker of 0 to 30 amino acids having any amino acid sequence can be used.
• an antigen-binding protein of the invention binds to HER2 and EGFR.
• a di-diabody of the invention binds to EGFR and IGFR.
• An example of an antigen binding protein that binds to EGFR and IGFR is provided in the examples (nucleotide and amino acid sequences: first polypeptide - SEQ ID NOS:55 and 56; second polypeptide - SEQ ID NOS:57 and 58).
• the linkers between the heavy and light chain variable domains are Arg-Thr-Val- AIa- Ala.
• the antigen-binding protein incorporates C H 2 and CH3 constant domains, and no linker was used between the hinge region and the constant domains.
• an antigen-binding protein of the invention binds to EGFR and a VEGFR.
• the VEGFR is VEGFR2.
• Such an antibody is useful for blocking stimulation of vascular epithelial cells, by blocking signal transduction through both EGFR and VEGFR. This is particularly useful where angiogenesis occurs in response to EGFR ligands, particularly TGR ⁇ , secreted by tumor cells.
• Di-diabodies of the invention can be used to cross-link antigens on target cells with antigens on immune system effector cells. This can be useful, for example, for promoting immune responses directed against cells which have a particular antigens of interest on the cell surface.
• immune system effector cells include antigen specific cells such as T cells which activate cellular immune responses and nonspecific cells such as macrophages, neutrophils and natural killer (NK) cells which mediate cellular immune responses.
• Di-diabodies of the invention can have a binding site for any cell surface antigen of an immune system effector cell.
• cell surface antigens include, for example, cytokine and lymphokine receptors, Fc receptors, CD3, CD 16, CD28, CD32 and CD64.
• antigen binding sites are provided by scFvs which are derived from antibodies to the aforementioned antigens and which are well known in the art.
• Antigen-binding sites of the invention which are specific for cytokine and lymphokine receptors can also be sequences of amino acids which correspond to all or part of the natural ligand for the receptor.
• an antigen-binding protein of the invention can have an antigen-binding site which comprises a sequence of amino acids corresponding or IL-2.
• Other cytokines and lymphokines include, for example, interleukins such as interleukin-4 (IL-4) and interleukin-5 (IL-5), and colony-stimulating factors (CSFs) such as granulocyte-macrophage CSF (GM-CSF), and granulocyte CSF (G-CSF).
• Di-diabodies of the invention are made by expressing two diabody chains, one of which is linked to at least one heavy chain constant domain that is capable of dimerization (e.g., CH2 and/or CH3).
• Di-diabodies are conveniently produced in E. coli using DNA constructs which comprise bacterial secretion signal sequences at the start of each polypeptide chain.
• a variety of bacterial signal sequences are known in the art.
• a perferred signal sequence is from the pelB gene of Erwinia carotovora.
• the DNA fragments coding for the diabodies can be cloned, e.g., into vectors employing human cytomegalovirus
• NYOl 924757 vl (HCMV) promoters and enhancers for high level expression in mammalian cells such as, for example, CHO, NSO, COS-7, and PER.C6 cells, and cell lines of lymphoid origin such as lymphoma, myeloma, or hybridoma cells.
• mammalian cells such as, for example, CHO, NSO, COS-7, and PER.C6 cells
• cell lines of lymphoid origin such as lymphoma, myeloma, or hybridoma cells.
• a selectable marker is a gene which encodes a protein necessary for the survival or growth of transformed host cells grown in a selective culture medium.
• Typical selectable markers encode proteins that (a) confer resistance to antibiotics or other toxins, e.g. ampicillin, neomycin, methotrexate, or tetracycline, (b) complement auxotrophic deficiencies, or (c) supply critical nutrients not available from complex media, e.g. the gene encoding D-alanine racemase for Bacilli.
• a particularly useful selectable marker confers resistance to methotrexate.
• cells transformed with the DHFR selection gene are first identified by culturing all of the transformants in a culture medium that contains methotrexate (Mtx), a competitive antagonist of DHFR.
• Mtx methotrexate
• An appropriate host cell when wild-type DHFR is employed is the Chinese hamster ovary (CHO) cell line deficient in DHFR activity, prepared and propagated as described by Urlaub and Chasin (1980) Proc. Natl. Acad. ScL USA 11, 4216.
• the transformed cells are then exposed to increased levels of methotrexate. This leads to the synthesis of multiple copies of the DHFR gene, and, concomitantly, multiple copies of other DNA comprising the expression vectors, such as the DNA encoding the antibody or antibody fragment.
• an example of a suitable selection gene for use in yeast is the trpl gene present in the yeast plasmid YRp7. Stinchcomb et al. (1979) Nature, 282, 39; Kingsman et al. (1979) Gene 1, 141.
• the trpl gene provides a selection marker for a mutant strain of yeast lacking the ability to grow in tryptophan, for example, ATCC No. 44076 or PEP4-1. Jones (1977) Genetics 85, 12.
• the presence of the trpl lesion in the yeast host cell genome then provides an effective environment for detecting transformation by growth in the absence of tryptophan.
• Leu2-deficient yeast strains (ATCC 20,622 or 38,626) are complemented by known plasmids bearing the Leu2 gene.
• Transformed host cells are cultured by methods known in the art in a liquid medium containing assimilable sources of carbon, e.g. carbohydrates such as glucose or lactose, nitrogen, e.g. amino acids, peptides, proteins or their degradation products such as
• the medium furthermore contains, for example, growth-promoting substances, such as trace elements, for example iron, zinc, manganese and the like.
• Di-diabodies that bind to growth factor receptors are preferably capable of blocking activation of receptor tyrosine kinase (RTK) activity.
• Tyrosine kinase inhibition can be determined using well-known methods, for example, by measuring the autophosphorylation level of recombinant kinase receptor, and/or phosphorylation of natural or synthetic substrates.
• phosphorylation assays are useful in determining RTK antagonists of the present invention. Phosphorylation can be detected, for example, using an antibody specific for phosphotyrosine in an ELISA assay or on a western blot.
• methods for detection of protein expression can be utilized to determine RTK antagonists, wherein expression of the proteins being measured is mediated by the RTK.
• RTK immunohistochemistry
• FISH fluorescence in situ hybridization
• competitive radioligand binding assays solid matrix blotting techniques, such as Northern and Southern blots, reverse transcriptase polymerase chain reaction (RT-PCR) and ELISA.
• RT-PCR reverse transcriptase polymerase chain reaction
• ELISA e.g., Grandis et al., Cancer, (1996) 78:1284-92; Shimizu et al., Japan J. Cancer Res., (1994) 85:567-71; Sauter et al. Am. J.
• the ability of a di-diabody to block ligand binding can be measured, for example, by an in vitro competitive assay.
• a ligand or the RTK e.g., EGF for EGFR
• a binding assay is carried out to determine the effectiveness of the di-diabody to competitively inhibit binding of the RTK to the immobilized ligand.
• In vivo assays can also be utilized to determine RTK antagonists.
• receptor tyrosine kinase inhibition can be observed by mitogenic assays using cell lines stimulated with receptor ligand in the presence and absence of inhibitor.
• NYOl 924757 vl A431 cells (American Type Culture Collection (ATCC), Rockville, MD) stimulated with EGF can be used to assay EGFR inhibition.
• Another method involves testing for inhibition of growth of EGFR-expressing tumor cells, using for example, human tumor cells injected into a mouse. See U.S. Patent No. 6,365,157 (Rockwell et al.).
• Preferred di-diabodies of the instant invention have dual specificity and are capable of binding to two different antigens simultaneously.
• the different antigens can be located on different cells or on the same cell.
• Cross linking of antigen can be shown in vitro, for example by providing a solid surface to which a first antigen has been bound, adding a bispecific antibodies specific for the first antigen and a second antigen for which the binding protein is also specific and detecting the presence of bound second antigen.
• Preferred bispecific di-diabodies of the invention are capable of blocking the interaction between two receptors and their respective ligands.
• a di-diabodies specific for KDR and FIt-I inhibits VEGF induced cell migration as well as PlGF induced cell migration.
• Combination of two receptor binding specificities in a bispecific di-diabodies can be more efficacious in inhibiting cell migration than the individual parent antibodies (see, e.g., WO 2004/003211; Zhu).
• bispecific di-diabodies can be more potent inhibitors of cellular function.
• VEGF-stimulated cellular functions such as, for example, proliferation of endothelial cells and VEGF- and PlGF-induced migration of human leukemia cells can be more efficiently inhibited by bispecific di- diabodies, even where affinity for one or both of the two target antigens is reduced.
• a diabody specific (monovalent) for both KDR and FIt-I is more effective to inhibit VEGF or PlGF induced cell migration than a monospecific scFv directed at either of the target antigens (WO 2004/003211).
• a di-diabody having dual specificity for both EGFR and IGFR that is capable of binding to both receptors and blocking interaction with their specific ligands is use to neutralizing both EFG and IGF-stimulated receptor activation and downstream signal transduction.
• Stimulation of either EGFR or IGFR results in phosphorylation of common downstream signal transduction molecules, including Akt and p44/42, although to different extents, hi certain tumor cells, inhibition of EGFR function can be compensated by upregulation of other growth factor receptor signaling pathways, and
• NYOl 924757 vl particularly by IGFR stimulation In contrast to treatment with an antibody binds to one receptor, and does not completely block phosphorylation of either Akt or p44/42, incubation of tumor cells with an antibody that binds to both EGFR and IGFR blocks phosphorylation of both Akt and p44/42. Accordingly, inhibition of IGFR signaling results in inhibition of tumor growth and increased sensitivity of tumor cells to certain therapeutic agents.
• the antigen-binding proteins are generally useful for treating neoplastic diseases characterized by cell growth or transformation resulting from activation of multiple signal transduction pathways.
• the antigen-binding proteins of the invention are useful for treatment of a variety of proliferative disorders.
• the present invention provides for treatment of tumors that express and are stimulated through more than one receptor tyrosine kinase. Stimulation through more that one receptor can result in uncontrolled growth that is insensitive to blockage of each receptor alone.
• stimulation of a second receptor can add to the activation observed in response to stimulation through a first receptor.
• the contributions from the individual receptors can be multiplicative. In each of the above instances, significantly improved inhibition of tumor growth is observed in the presence of an antigen-binding protein that blocks both of the receptors.
• the antigen-binding proteins of the invention are useful for treating diseases in which receptor stimulation is through an EGFR paracrine and/or autocrine loop.
• EGFR expressing tumors are characteristically sensitive to EGF present in their environment, and can further be stimulated by tumor produced EGF or TGF- ⁇ .
• the diseases and conditions that may be treated or prevented by the present methods include, for example, those in which tumor growth is stimulated. The method is therefore effective for treating a solid tumor that is not vascularized, or is not yet substantially vascularized.
• antigen-binding proteins of the invention are useful for inhibiting angiogenesis associated with a hyperproliferative disease. For example, by blocking tumor associated angiogenesis, tumor growth may be inhibited.
• the antigen- binding protein binds to a tumor associated RTK and inhibits production of angiogenic
• NYOl 924757 vl ligands i.e., VEGF
• VEGF vl ligands
• the antigen- binding protein binds to multiple VEGF receptors, such that VEGF or other ligand of VEGFR (e.g., PlGF) ligand is blocked from binding to more than one type of VEGF receptor.
• VEGFR e.g., PlGF
• Tumors that may be treated include primary tumors and metastatic tumors, as well as refractory tumors.
• Refractory tumors include tumors that fail to respond or are resistant to treatment with chemotherapeutic agents alone, antibodies alone, radiation alone or combinations thereof.
• Refractory tumors also encompass tumors that appear to be inhibited by treatment with such agents, but recur up to five years, sometimes up to ten years or longer after treatment is discontinued.
• the tumors may express EGFR or other RTK at normal levels or they may overexpress the RTK at levels, for example, that are at least 10, 100, or 1000 times normal levels.
• tumors that express EGFR and are stimulated by a ligand of EGFR include carcinomas, gliomas, sarcomas, adenocarcinomas, adenosarcomas, and adenomas.
• Such tumors can occur in virtually all parts of the body, including, for example, breast, heart, lung, small intestine, colon, spleen, kidney, bladder, head and neck, ovary, prostate, brain, pancreas, skin, bone, bone marrow, blood, thymus, uterus, testicles, cervix or liver.
• tumors observed to overexpress EGFR include, but are not limited to, colorectal and head and neck tumors, especially squamous cell carcinoma of the head and neck, brain tumors such as glioblastomas, and tumors of the lung, breast, pancreas, esophagus, bladder, kidney, ovary, cervix, and prostate.
• tumors observed to have constitutively active (i.e., unregulated) receptor tyrosine kinase activity include gliomas, non-small-cell lung carcinomas, ovarian carcinomas and prostate carcinomas.
• tumors include Kaposi's sarcoma, CNS neoplasms, neuroblastomas, capillary hemangioblastomas, meningiomas and cerebral metastases, melanoma, gastrointestinal and renal carcinomas and sarcomas, rhabdomyosarcoma, glioblastoma, preferably glioblastoma multiforme, and leiomyosarcoma.
• RTKs Overexpression of other RTKs can produce similar growth defects. For example, most metastatic bone cancers arise from primary tumors of prostate, breast, or lung. Prostate tumors initially may be hormone dependent, but loss of such dependence coincides with IGFR mediated stimulation of cells that migrate to bone.
• hyperproliferative disease is defined as a condition caused by excessive growth of non-cancer cells that express a member of the EGFR family or other tyrosine kinase receptors. The excess cells generated by a hyperproliferative disease express the RTK at normal levels or they may overexpress the RTK.
• hyperproliferative disease examples include psoriasis, actinic keratoses, and seborrheic keratoses, warts, keloid scars, and eczema. Also included are hyperproliferative diseases caused by virus infections, such as papilloma virus infection. For example, psoriasis comes in many different variations and degrees of severity.
• psoriasis display characteristics such as pus-like blisters (pustular psoriasis), severe sloughing of the skin (erythrodeimic psoriasis), drop-like dots (guttae psoriasis) and smooth inflamed lesions (inverse psoriasis).
• the treatment of all types of psoriasis e. g., psoriasis vulgaris, psoriasis pustulosa, psoriasis erythrodermica, psoriasis arthropathica, parapsoriasis, palmoplanar pustulosis
• psoriasis vulgaris e.g., psoriasis vulgaris, psoriasis pustulosa, psoriasis erythrodermica, psoriasis arthropathica, parapsoriasis, palmoplanar
• di-diabodies can be chemically or biosynthetically conjugated to other agents such as antineoplastic or anti-angiogenic agents for treatment of disease.
• Anti-tumor agents linked to an antibody include any agents which destroy or damage a tumor to which the antibody has bound or in the environment of the cell to which the antibody has bound.
• an anti-tumor agent is a toxic agent such as a chemotherapeutic agent or a radioisotope.
• the chemotherapeutic agents are conjugated to the di-diabody using conventional methods ⁇ See, e.g., Hermentin and Seiler (1988) Behring Inst. Mitt. 82, 197-215), including by peptide and non-peptide linkers.
• Di-diabodies can also be linked to detectable signal-producing agents useful in vivo and in vitro for diagnostic purposes.
• the signal producing agent produces a measurable signal which is detectible by external means, usually the measurement of electromagnetic radiation.
• the signal producing agent is an enzyme or chromophore, or emits light by fluorescence, phosphorescence or chemiluminescence.
• Chromophores include dyes which absorb light in the ultraviolet or visible region, and can be substrates or degradation products of enzyme catalyzed reactions.
• the invention further contemplates the use of di-diabodies with treatment or diagnostic agents incorporated into secondary reagents.
• one member of a binding pair is linked to the di-diabody of the invention.
• Anti-neoplastic agents are conjugated to second members of such pairs and are thereby directed to the site where the di-diabody is bound, hi a preferred embodiment, biotin is conjugated to a di-diabody, and thereby provides a target for an anti-neoplastic agent or other moiety which is conjugated to avidin or streptavidin.
• biotin or another such moiety is linked to a di-diabody of the invention and used as a reporter, for example in a diagnostic system where a detectable signal-producing agent is conjugated to avidin or streptavidin.
• Di-diabodies can be administered in combination with one or more suitable adjuvants, such as, for example, cytokines (IL-10 and IL- 13, for example) or other immune stimulators, such as, but not limited to, chemokine, tumor-associated antigens, and peptides. It should be appreciated, however, that administration of only a diabody is sufficient to prevent, inhibit, or reduce the progression of the tumor in a therapeutically effective manner.
• suitable adjuvants such as, for example, cytokines (IL-10 and IL- 13, for example) or other immune stimulators, such as, but not limited to, chemokine, tumor-associated antigens, and peptides.
• an antigen-binding protein of the invention that binds to an RTK and blocks ligand binding in combination with another antigen-binding protein that binds to ligand.
• Ligand binding antibodies are well known in the art, and include, e.g., anti-VEGF (Avastin ® ; bevacizumab).
• the di-diabodies of the invention are also to be used in combined treatment methods by administration with an anti-neoplastic agent such as a chemotherapeutic agent or a radioisotope.
• chemotherapeutic agents include irinotecan (CPT-Il), anthracyclines (e.g. daunomycin and doxorubicin), methotrexate, vindesine, neocarzinostatin, cisplatin, chlorambucil, cytosine arabinoside, 5-fluorouridine, melphalan, ricin and calicheamicin.
• a di-diabody and an anti-angiogenic or anti-neoplastic agent are admininstered to a patient in amounts effective to inhibit angiogenesis and/or reduce tumor growth.
• the di-diabodies are also to be administered in combination with other treatment regimes, for examplej with treatments such as radiation therapy.
• combination therapies see, e.g., U.S. Patent No. 6,217,866 (Schlessinger et al.) (Anti-EGFR antibodies in combination with anti-neoplastic agents); WO 99/60023 (Waksal et al.) (Anti-EGFR antibodies in combination with radiation).
• any suitable anti-neoplastic agent can be used, such as a chemotherapeutic agent, radiation or combinations thereof.
• the anti-neoplastic agents known in the art or being evaluated can be grouped in to classes based on their target or mode of action.
• alkylating agents include, but are not limited to, cisplatin, cyclophosphamide, melphalan, and dacarbazine.
• anti-metabolites include, but not limited to, doxorubicin, daunorubicin, and paclitaxel, gemcitabine, and topoisomerase inhibitors irinotecan (CPT-Il), aminocamptothecin, camptothecin, DX-8951f, and topotecan (topoisomerase I) and etoposide (VP-16) and teniposide (VM-26) (topoisomerase II).
• the source can be either external (external beam radiation therapy — EBRT) or internal (brachytherapy - BT) to the patient being treated.
• EBRT internal beam radiation therapy
• brachytherapy - BT teniposide
• Such classifications can be useful for choosing an antineoplastic agent to use. For example, it has been observed that antibodies that bind IGFR may be particularly effective when administered with a topoisomerase inhibitor.
• the dose of anti-neoplastic agent administered depends on numerous factors, including, for example, the type of agent, the type and severity tumor being treated and the route of administration of the agent. It should be emphasized, however, that the present invention is not limited to any particular dose.
• the di-diabody is administered before, during, or after commencing therapy with another agent, as well as any combination thereof, i.e., before and during, before and after, during and after, or before, during and after commencing the anti-neoplastic agent therapy.
• the diabody can be administered between 1 and 30 days, preferably 3 and 20 days, more preferably between 5 and 12 days before commencing radiation therapy.
• chemotherapy is administered concurrently with, prior to, or subsequent to antibody therapy.
• any suitable method or route can be used to administer di-diabodies of the invention, and optionally, to co-administer anti-neoplastic agents, receptor antagonists, or other pharmaceutical composition.
• anti ⁇ neoplastic agent regimens utilized according to the invention include any regimen believed to be optimally suitable for the treatment of a patient's neoplastic condition. Different malignancies can require use of specific anti-tumor diabodies and specific anti-neoplastic agents, which will be determined on a patient to patient basis. Routes of administration
• NYOl 9247 5 7 vl include, for example, oral, intravenous, intraperitoneal, subcutaneous, or intramuscular administration.
• the dose of anti-neoplastic agent administered depends on numerous factors, including, for example, the type of neoplastic agent, the type and severity tumor being treated and the route of administration of the antineoplastic agent. It should be emphasized, however, that the present invention is not limited to any particular method or route of administration.
• di-diabodies of the invention where used in a mammal for the purpose of prophylaxis or treatment, will be administered in the form of a composition additionally comprising a pharmaceutically acceptable carrier.
• suitable pharmaceutically acceptable carriers include, for example, one or more of water, saline, phosphate buffered saline, dextrose, glycerol, ethanol and the like, as well as combinations thereof.
• Pharmaceutically acceptable carriers can further comprise minor amounts of auxiliary substances such as wetting or emulsifying agents, preservatives or buffers, which enhance the shelf life or effectiveness of the binding proteins.
• the compositions of the injection can, as is well known in the art, be formulated so as to provide quick, sustained or delayed release of the active ingredient after administration to the mammal.
• kits for inhibiting tumor growth and/or angiogenesis, or treating other disesase comprising a therapeutically effective amount of a human di-diabody.
• the kits can further contain any suitable antagonist of, for example, another growth factor receptor involved in tumorigenesis or angiogenesis (e.g., EGFR, VEGFR-l/Flt-1, VEGFR-2/Flk-l/KDR, IGFR, PDGFR, NGFR, FGFR, etc, as described above).
• the kits of the present invention can further comprise an anti-neoplastic agent. Examples of suitable anti-neoplastic agents in the context of the present invention have been described herein.
• the kits of the present invention can further comprise an adjuvant; examples have also been described above.
• kits which contain di-diabodies of the present invention.
• the present receptor binding di-diabodies thus can be used in vivo and in vitro for investigative, diagnostic, prophylactic, or treatment methods, which are
• soluble receptor fusion proteins the extracellular domain of kinase inserting domain-containing receptor (KDR)-alkaline phosphatase (AP), and the extracellular domain of fins-like tyrosine kinase receptor (FIt-I)-AP, were expressed in stably transfected NIH 3T3 cells and purified from cell culture supernatant by affinity chromatography using immobilized monoclonal antibody to AP as described (Lu et al. (2000) J. Biol. Chem. 275:14321-30).
• VEGF165 Vascular endothelial growth factor
• the single chain antibody directed against KDR, scFv pi Cl 1 was isolated from a phage display library constructed from the splenocytes of a mouse immunized with KDR-AP fusion protein (Zhu et al. (1998) Cancer Res. 58:3209-14).
• Hybridoma cell line producing the anti-Flt-1 antibody, FBK612 (IgGl, K) was established at ImClone Systems Incorporated (New York, NY) from mice immunized with FIt-I -AP fusion protein.
• the single chain version of FBK612, scFv The single chain version of FBK612, scFv
• NYOl 924757 vl 612 was constructed from the antibody variable genes isolated from the hybridoma cells as previously reported (Lu et al. (2001)).
• the diabodies were secreted from E. coli strain HB2151 containing the expression plasmid grown at 30°C in a shaker flask following the procedure previously described (Lu et al., 2000; Zhu et al., 1998).
• a periplasmic extract of the cells was prepared by resuspending the cell pellet in 25 mM Tris (pH 7.5) containing 20% (w/v) sucrose, 200 mM NaCl, 1 mM EDTA and 0.1 mM PMSF 5 followed by incubation at 4°C with gentle shaking for 1 h.
• the diabodies were purified from the supernatant by an anti-E tag affinity chromatography using the RPAS Purification Module (Amersham Pharmacia Biotech). To examine the purity of the diabody preparations, the purified proteins were electrophoresed in a 4-20% gradient polyacrylamide gel (Novex, San Diego, CA) and visualized by staining with Colloidal Blue Stain kit (No vex).
• the di-diabody was also expressed in mammalian COS cells. Nucleic acids encoding both of the polypeptides, each fused with an identical immunoglobulin leader
• NYOl 924757 vl peptide sequence on its N-terminus were cloned into a single expression vector (the glutamine synthetase expression system from Lonza Biologies Inc.).
• Sub- confluent COS cells were transfected with the expression vector using Lipofectamine following the instructions of the manufacturer (Invitrogen). The cells were cultured in serum-free medium, and supernatant was collected at 48 to 72 h after the transfection. After centrifugation to remove the cell debris, the di-diabody was purified from the supernatant using the RPAS Purification Module as described above.
• the yield of the purified di-diabody ranged from 150 to 250 ⁇ g per liter of overnight bacteria culture in shaker flask, and approximately 800 to 1250 ⁇ g per liter of supernatant 48 to 72 h after transfection of the mammalian culture.
• the composition and purity of the purified di-diabody preparations, both from E. coli expression [di-diabody (B)] and from mammalian expression [di-diabody (M)] was analyzed using SDS-PAGE (Fig. 2).
• the components of the "cross-over" scFv in a bispecific diabody were also resolved by electrophoresis.
• the divalent bispecific diabody, DAB pi Cl 1/612 yielded two bands (Fig. 2 A, lane 3), representing each one of the two "cross ⁇ over" scFv polypeptide chains (theoretical m.w., 26693.8 and 25179.6 daltons for the upper and the lower band, respectively).
• the di-diabody preparation also gave two major bands (Fig.
• the lower band representing the "cross-over” scFv chain (the same band as in DAB plCl 1/612), whereas the upper band represents the "cross-over” scFv-hinge-C H 3 fusion in dimer form (theoretical m.w., 79175.3 daltons).
• the di-diabody yielded two major bands: the lower band represents the original "cross ⁇ over” scFv chain, and the top band corresponds to the reduced scFv-hinge-CH3 fusion in monomer form.
• DAB 612 yielded one major band under both reducing and non-reducing conditions (lane 2, theoretical m.w. 26916.9 daltons).
• DAB plCl 1 gave two bands (lane 1): the upper band corresponds to the single polypeptide, VL-G4S-VH, with intact E-tag (theoretical m.w. 26542.4 daltons); the lower band represents the same polypeptide with E-tag degradation.
• the di-diabody yielded three distinct peaks on SEC.
• ASTRA-computed Zimm analysis indicated a monodispersed peak (75% of the population) with a M w value of 132 kD, a monodispersed peak (20% of the population) with a M w value of 270 kD and a polydispersed peak (5% of the population) with a M w value of 470 kD.
• the 132 kD peak represents the correctly folded monomelic di-diabody
• the 270 kD peak represents the dimeric form of the di-diabody
• the polydispersed 470 kD peak is a heterogeneous population with respect to oligomeric state.
• an intact IgG antibody with a theoretical m.w. of 150 kD yielded a single peak with a estimated M w value of 150 kD
• a diabody with a theoretical m.w. of 60 kD yielded a single peak with a estimated M w value of 62 kD, under identical conditions.
• Two ELISA assays were carried out to determine the dual antigen binding capability of the bispecific di-diabody.
• a cross-linking assay was used to investigate whether the di-diabody is capable of binding both of its target antigens simultaneously.
• the monospecific diabodies, the bispecific diabody and di-diabody were first incubated in the presence of 1 mM of dithiothreitol (DTT) in a 96-well Maxi-sorp microtiter plate (Nunc, Roskilde, Denmark) precoated with FIt-I-Fc fusion protein (1 ⁇ g/ml x 100 ⁇ l per well overnight at 4°C) at RT for 1 h.
• DTT dithiothreitol
• the plate was washed three times with PBS containing 0.1 % Tween (PBST), followed by incubation with KDR-AP fusion protein (100 ng/well) at RT for additional 1 h.
• KDR-AP fusion protein 100 ng/well
• the plate-bound KDR-AP was then quantified by the addition of AP
• the di-diabody was reduced into two half molecules, each consisting of a single diabody-C ⁇ 3 fusion (Fig. 1). Both the reduced divalent bispecific diabody and di-diabody, but not the monospecific diabody (DAB pi Cl 1 and DAB 612), were able to cross-link the two target antigens (Fig. 3, top panel). This observation indicates that the di-diabody, a dimer of two diabody-C ⁇ 3 fusions, possesses four antigen-binding sites (two on each C H 3 arm).
• the direct binding assay various amounts of the diabodies were added to KDR or FIt-I -coated 96-well plates and incubated at RT for 1 h, after which the plates were washed 3 times with PBS. The plates were then incubated at RT for 1 h with 100 ⁇ l of an anti-E tag antibody-HRP conjugate (Amersham Pharmacia Biotech). The plates were washed, peroxidase substrate added, and the absorbance at 450nm read following the procedure described previously (Lu et al., 1999; 2000).
• coli-de ⁇ ved di- diabody (B) demonstrated kinetic constants that are very similar to those of the scFv 612 and DAB pi Cl 1/612, whereas the mammalian cell-derived material showed a much slower association rate ikon), along with a significantly improved dissociation rate (koff) that is approaching that of the bivalent DAB 612.
• *A11 numbers are determined by BIAcore analysis and represent the mean ⁇ SE of at least four separate determinations. Kd values are calculated as the ratios of & off / Ar 0n . **NDB, no detectable binding.
• the assay was carried out following a previously described protocol (Lu et al., 1999; 2000). Various amounts of the diabodies were mixed with a fixed amount of KDR-AP (100 ng) or FIt-I -AP fusion protein (100 ng) and incubated at RT for 1 h. The mixture were then transferred to 96-well microtiter plates precoated with VEGFl 65 (200 ng/well) and incubated at RT for an additional 2 h, after which the plates were washed 5 times with PBS. The substrate for AP was added, followed by reading of the absorbance at 405nm to quantify the plate-bound KDR-AP or FIt-I -AP molecules. The IC50, i.e., the antibody concentration required for 50% inhibition of KDR or FIt-I binding to VEGF, was then calculated.
• Fig. 4 shows that the diabodies block soluble KDR and FIt-I from binding to immobilized VEGF, in a dose-dependent manner.
• the tetravalent di-diabody preparations were more potent blockers to both KDR/VEGF and Flt-1/VEGF interaction than the divalent diabody, DAB plCl 1/612.
• the IC 50 values for KDR blocking were approximately 0.4 nM for both di-diabody preparations, compared to that of 1.2 nM for DAB plCl 1/612 and 0.8 nM for the monospecific bivalent DAB plCl 1.
• the IC 50 for FIt-I blocking was approximately 1 nM for both di-diabody preparations, 8 nM for DAB plCl 1/612 and 0.2 nM for the monospecific bivalent DAB 612.
• DAB plCl 1 had no effects on Flt-1/VEGF interaction
• DAB 612 had no effects on KDR/VEGF interaction.
• HEL human leukemia cell lines
• U937 that only expresses FIt-I
• Leukemia cells, HEL and U937 were washed three times with serum-free plain RPMI 1640 medium and suspended in the medium at 1 x 10 6 /ml. Aliquots of 100 ⁇ l cell suspension were added to 8- ⁇ m-pore transwell inserts (Costar®, Corning Incorporated, Corning, NY) and incubated with the antibodies at various concentrations, 100 nM, 25 nM and 6.25 nM, for 30 min at 37°C.
• the inserts were then placed into the wells of 24-well plates containing 0.5 ml of serum-free RPMI 1640 with or without VEGF165.
• the migration was carried out at 37°C, 5% CO2 for 4 h.
• Migrated cells were collected from the lower compartments and counted under a light microscope.
• the stability of the di-diabodies was tested by examination of their binding activity to both KDR and FIt-I.
• the divalent bispecific diabody, DAB plCl 1/612, and the monospecific diabodies, DAB plCl 1 and DAB 612 retained full antigen binding activity to their respective targets after incubation at 37 0 C in both PBS and mouse serum.
• the mammalian cell-derived di-diabody (M) preparation retained better antigen-binding activity compared to the E.c ⁇ /z-derived preparation.
• di-diabody (M) showed 94% of the original KDR-binding activity, compared to that of 83% for di-diabody (B).
• di-diabody (M) retained 77% and 92% binding activities to KDR and FIt-I, respectively, compared to those of 63% and 86% for di-diabody (B).
• variable regions of a fully human anti- ⁇ GFR antibody (IMC-11F8) and a fully human anti-IGF-IR antibody (IMC-Al 2) were used to construct a bispecific di-diabody.
• Bispecific diabodies were constructed as above, followed by fusion of one of the diabody cross-over scFv chains to the Fc domain of an IgG (see Fig. 7A and 7B for details).
• Co-expression in mammalian cells the Fc fusion along with the other cross-over scFv resulted in an IgG-like tetravalent molecule with two binding specificities (Fig. 7B).
• the di-diabody was produced by stably transfected NSO cells in serum-free conditions and purified from the cell culture supernatant via a Protein A affinity column. Electrophoresis analysis of the purified di-diabody under non-reducing conditions yielded two major protein bands with
• the di-diabodv binds to both EGFR and IGFR
• a direct binding assay was used to compare antigen-binding efficiency of the di-diabody with its monospecific counterparts.
• IMC-Al 2 and BVIC-11F8 bound only to their respective targets, whereas the di-diabody reacted to both immobilized EGFR and IGFR, with moderately lower efficiencies as compared to its monospecific counterparts (Fig. 2B and 2C).
• the ED50 values ⁇ i.e., the antibody concentrations that yield 50% of maximum binding) to EGFR were 0.05 nM for BVIC-11F8 and 0.1 - 0.2 nM for the Di-diabody, and to IGFR were 0.1 nM for BVIC-A12 and 0.25 - 0.5 nM for the Di-diabody.
• the efficacy of the di-diabody in inhibiting tumor cell proliferation in vitro was established using a well-characterized tumor cell line, DiFi, which is known to depend on EGFR for survival and growth.
• DiFi a well-characterized tumor cell line
• the anti-EGFR antibody (BvIC-11F8) significantly inhibited the proliferation of DiFi cells, whereas the anti-IGFR antibody (DVIC-A12), and the control antibody (EvIC-1121; anti-KDR) had little effect (Fig. 9).
• Proliferation of the DiFi cells was also inhibited by the di-diabody, although at higher concentrations than BVIC-11F8.
• the IC50 values were approximately 1 nM for IMC-11F8 (alone), InM for the coadministered combination of IMC-11F8 and IMC-Al 2, and 25 nM for the di-diabody.
• the di-diabody was assayed for efficacy in blocking EGF and IGF-stimulated receptor phosphorylation and downstream signal transduction.
• Incubation of MCF-7 cells with EGF or IGF results in significant phosphorylation of the respective receptor; incubation with a combination of EGF and IGF yields activation of both EGFR and IGFR (Fig. 1OA, lanes 2, 3, and 4).
• Fig. 1OA EGFR and IGFR
• the di-diabody like the mixture of both EVIC-11F8 and EV ⁇ C-12, significantly blocked activation of both receptors (Fig. 1OA, lanes 5 and 8).
• the control antibody, IMC-1121 showed no effect on the phosphorylation of EGFR and IGFR (Fig. 1OA, lane 9).
• IMC-11F8 significantly inhibited the activation of MAPK but only moderately reduced the activation of Akt (Fig. 1OB, lane 7), whereas EVIC-A12 strongly reduced Akt phosphorylation but was less effective in p44/p42 MAPK activation (Fig. 1OB, lane 6).
• the di-diabody effectively blocked phosphorylation of both Akt and p44/p42 MAPK induced by EGF and IGF (Fig. 1OB, lane 5) as did the combination of BVIC-A12 and IMC-11F8 (Fig. 10, lane 8).
• IMC-A12 has been shown to induce rapid and efficient internalization and degradation of cell surface expressed IGFR (Burtrum et al., 2003, Cancer Res. 63:8912).
• the di-diabody retained the receptor modulation activity of EVIC-A12 on tumor cells, triggering significant IGFR internalization and degradation in MCF-7 cells after incubation at 37°C for
• antitumor IgG antibodies can also cause direct tumor cell killing via mediating effective ADCC.
• the ability of the di-diabody to mediate tumor-cell killing in the presence of human efffector cells was examined. As shown in Fig. 12, BVIC-11F8 demonstrated lytic activity against both A431 and BxPC3 cells but was ineffective against MCF-7 cells. EVIC-Al 2 was effective only towards MCF-7 cells but failed to kill A431 and BxPC3 cells. The di-diabody, mediated killing of all the three tumor lines.
• HT29 xenografts were less responsive to treatment with individual anti-EGFR or anti-IGFR antibodies than to treatment with the di- diabody (Fig. 13B).
• NYOl 924757 vl that is functionally equivalent to IMC-11F8 regarding both in vitro and in vivo antitumor activity (Marie, P. et al., 2004, Proc. Amer. Assoc. Cancer Res. 45, Abstract #5353) resulted in tumor inhibition of 47% and 35% at day 40 post treatment, respectively (p ⁇ 0.03 compared to the saline and the human IgG groups).
• the di-diabody yielded a tumor growth inhibition rate of 58%, which is comparable to that achieved by the combination of both IMC-C225 and IMC-A12 (63% tumor growth inhibition). There is no statistically significant difference in overall tumor inhibition, however, between groups treated with the di-diabody, the antibody combination, or the individual antibody at the end of the study.

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