Patent Description:
Many severe diseases are linked to malfunctions of the TGFβ-induced signaling pathway. For instance, an increased tissue level of TGFβ is believed to be a factor in the development of idiopathic pulmonary fibrosis and myocardial fibrosis. Furthermore, high local tissue levels of TGFβ may allow the maintenance and progression of some types of cancer cells. Down-regulation of TGFβ signaling therefore may reduce the viability of such tumor cells.

TGFβ isoforms are ~<NUM> kDa homodimeric molecules with a similar structural framework in which two monomers are covalently linked via a disulfide bridge. The mammalian isoforms share a sequence identity of <NUM>-<NUM>%, but have non-overlapping activities in vascular development and the regulation of immune cell function. Three TGFβ isoforms have been reported in humans: TGFβ1, TGFβ2, and TGFβ3 (Swiss Prot accession numbers P01137, P08112, and P10600, respectively). TGFβ1 and TGFβ3 trigger a cellular signaling cascade upon binding to the extracellular domains of two transmembrane receptors, known as TGFβ receptor types I and II. TGFβ2 may bind to TGFβ receptor types I and II, as well as TGFβ receptor type III.

Antibodies that can bind human TGFβ1, TGFβ2, and TGFβ3 have been tested for clinical use. For instance, Grütter et al. disclosed GC1008, a human IgG4 monoclonal antibody (Mab; i.e., GC1008) in clinical development for treating malignancy and fibrotic diseases. GC1008 is a "pan-specific" TGFβ neutralizing antibody, because it can neutralize all three human TGFβ isoforms. Antibodies that selectively neutralize TGFβ1 are disclosed, for example, in <CIT> and <CIT>. Metelimumab, also known as CAT192 (IgG4), is a human IgG4 monoclonal antibody that selectively neutralizes TGF-β1. See e.g., <CIT>. Metelimumab was tested for the treatment of diffuse cutaneous systemic sclerosis, also known as scleroderma, but demonstrated insufficient efficacy. <CIT>, <CIT> and <CIT> disclose antibodies having a higher affinity for human TGFβ1 as compared to human TGFβ2 and/or TGFβ3. <CIT> discloses TGFβ1 neutralizing antibodies based on specific CDR3 regions from antibody SL15 and JT182. <NPL>) report a vector for rapid expression of an scFv-Fc fusion protein in Pichia pastoris.

The invention is as defined in the accompanying claims. Specifically, the present invention provides an isolated binding protein that selectively binds human TGFβ1, wherein said binding protein is a homodimer of a polypeptide chain having the formula of, from N-terminus to C-terminus: (VH domain)-(linker1) -(VL domain)-(linker2) -(hinge) -(Fc region), wherein the VH domain comprises SEQ ID NO: <NUM> and the VL domain comprises SEQ ID NO: <NUM>; the linker1 comprises SEQ ID NO: <NUM> or SEQ ID NO: <NUM>; the linker2 comprises SEQ ID NO:<NUM> or a variant thereof, wherein the variant differs from SEQ ID NO:<NUM> by having up to two amino acid substitutions from glycine to serine or from serine to glycine; and the hinge comprises an amino acid sequence from a human IgG1 hinge region comprising the amino acid sequence of SEQ ID NO:<NUM>; and wherein the Fc region is a human IgG1 or a human IgG4 Fc region.

The VH domain of the disclosed binding protein comprises a variable heavy complementarity determining region <NUM> (HCDR1) , a variable heavy complementarity determining region <NUM> (HCDR2), and a variable heavy complementarity determining region <NUM> (HCDR3), wherein the HCDR1 has the amino acid sequence of SEQ ID NO: <NUM>, the HCDR2 has the amino acid sequence of SEQ ID NO: <NUM>, and the HCDR3 has the amino acid sequence of SEQ ID NO: <NUM>.

The VL domain of the disclosed binding protein comprises a variable light complementarity determining region <NUM> (LCDR1) , a variable light complementarity determining region <NUM> (LCDR2), and a variable light complementarity determining region <NUM> (LCDR3), wherein the LCDR2 has the amino acid sequence of SEQ ID NO: <NUM>, and the LCDR3 has the amino acid sequence of SEQ ID NO: <NUM>.

The linker1 has the amino acid sequence SGGGSGGGGSGGGGS (SEQ ID NO: <NUM>), or the amino acid sequence GGGGSGGGGSGGGGS (SEQ ID NO: <NUM>).

The hinge comprises the amino acid sequence derived from a human IgG1 hinge region having the amino acid sequence CPPCP (SEQ ID NO: <NUM>).

In accordance with the invention, linker2 comprises the amino acid sequence GGSG (SEQ ID NO: <NUM>), or a variant thereof having up to <NUM> amino acid modifications from glycine to serine or from serine to glycine.

The Fc region is a human IgG1 or a human IgG4 Fc region. In one embodiment, each polypeptide of the dimer has the sequence set forth in SEQ ID NO: <NUM>. The structure of the scFv-Fc dimer of SEQ ID NO: <NUM> is shown in <FIG>. The scFv-Fc dimer may bind TGFβ1 selectively. The scFv-Fc dimer may show an apparent dissociation constant less than <NUM> or even less than <NUM>. The apparent dissociation constant may be measured by using an A549 bioassay or by surface plasmon resonance, for example. The scFv-Fc dimer of the present invention may be an element of a pharmaceutical composition. The pharmaceutical composition may comprise a therapeutically effective amount of the scFv-Fc dimer. The composition may further comprise one or more biologically active components, excipients, or diluents.

The present invention also provides the isolated binding protein or a pharmaceutical composition comprising the same and a pharmaceutically acceptable excipient for use in treating a disease in a human in need of inhibition of TGFβ1 activity , wherein the disease is a fibrotic disease, cancer, an immune-mediated disease, e.g., diffuse cutaneous systemic sclerosis, bone remodeling disease, or a kidney disease. The treatment of the disease or disorder may comprise neutralizing TGFβ1 or inhibiting TGFβ1 signaling. The treatment of the disease may comprise inhibiting TGFβ1-mediated fibronectin production, vascular endothelial growth factor (VEGF) production, epithelial cell proliferation, endothelial cell proliferation, smooth muscle cell proliferation, or immunosuppression. The treatment of the disease may comprise increasing natural killer cell activity.

Further aspects and embodiments of the present invention are disclosed in the accompanying claims.

The drawings presented herein are for purpose of illustration and are not to be used to limit the scope of the present invention.

The disclosed scFv-Fc dimers bind and neutralize TGFβ1 selectively and with high affinity and avidity. scFv-Fc dimers advantageously show greater efficacy in neutralizing TGFβ1 than when the variable domains are used in other formats. Because of their relatively small size and extended half-life in serum, the present scFv-Fc dimers are ideal candidates for therapeutic applications.

As used herein, a first element "and/or" a second element means a specific disclosure of the first or second element separately, or the first and second elements in combination.

An "isolated" polynucleotide (or nucleic acid) or protein is removed and/or altered from its natural form using genetic engineering technologies. A "purified" nucleic acid or protein may be substantially pure, e.g., at least <NUM>% pure, or in homogeneous form.

"Selective binding", or "binding selectively" to human TGFβ1, means that the binding protein (e.g., scFv-Fc dimer) is capable of binding human TGFβ1 with a higher affinity than binding to human TGFβ2 or human TGFβ3, e.g., with a dissociation constant with human TGFβ1 at least <NUM>% lower than its dissociation constant with human TGFβ2 or human TGFβ3, as measured by surface plasmon resonance.

The VH domain comprises the HCDR1 of SEQ ID No. <NUM>, the HCDR2 of SEQ ID No. <NUM>, and the HCDR3 of SEQ ID No. <NUM>. The VL domain comprises the LCDR2 of SEQ ID NO: <NUM>, and the LCDR3 of SEQ ID NO: <NUM>.

A "variable domain" (VD) refers to a hypervariable binding domain of an immunoglobulin, or a ligand binding domain of a receptor, involved in antigen/ligand binding as is known by persons skilled in the art. Variable domains are routinely referred to by their location or origin within an immunoglobulin; e.g., variable domains of the light chain of an immunoglobulin (VL), variable domains of the heavy chain of an immunoglobulin (VH), variable domains of the heavy chain of a camelid immunoglobulin (VHH).

A "variant" variable domain comprises amino acid additions, substitutions, and/or deletions, compared to the reference sequence. A "variant" of the VH or VL domains may have up to four such amino acid modifications. For example, one of the two domains may comprise an amino acid substitution, while the other domain is unmodified, or both of the domains may comprise amino acid substitutions. Modifications that add or delete amino acid residues may be made at the N-terminus or C-terminus of the VH or VL domain. For example, the N-terminal residue of the VH domain may be deleted.

Up to four amino acid substitutions may be made to de-immunize the scFv-Fc dimer, for example. De-immunization can be performed according to the method of <NPL>, for example.

Framework residues of the VH and/or VL domains, for example, may be substituted to increase the stability of the scFv-Fc dimers and/or decrease their tendency to aggregate. Poor stability can affect the ability of the expressed scFv-Fc dimers to fold properly when recombinantly expressed, resulting in a fraction of the expressed antibodies being non-functional. Low stability antibodies also may be prone to forming potentially immunogenic aggregates or may have impaired avidity or shelf-life. scFv polypeptides in particular may demonstrate problems with stability, solubility, expression, aggregation, breakdown products, and overall manufacturability in both bacterial and mammalian expression systems. Framework amino acid substitutions that are expected to increase the stability and/or decrease the tendency to aggregate of a VH and/or VL domain, e.g., in an scFv polypeptide, are disclosed in <CIT>, for example. Substitutions in corresponding residues in the present VH and VL domains are expected similarly to increase stability and/or decrease the tendency of scFv-Fc dimers to aggregate.

Substitutions that can be tolerated are expected to include those that would replace an amino acid of SEQ ID NO: <NUM>, <NUM>, <NUM>, or <NUM> with a corresponding amino acid that occurs in another human VH or VL domain germline sequence. A substitution of a framework amino acid with an amino acid occurring in any of these germline sequences may be tolerated. For example, a residue of a VH domain of SEQ ID NO: <NUM> could be substituted with an amino acid appearing in a corresponding position in any VH germline sequence, e.g., the germline sequence from DP-<NUM> (VH <NUM>-<NUM>) or DP-<NUM> (VH <NUM>-e). Corresponding positions in this case are determined by a sequence alignment between the various germline sequences, using alignment techniques well known in the art, e.g., ClustalW.

Additional substitutions that are expected to be tolerated are those made to an amino acid with most of its side chain exposed to the solvent, as determined by analysis of the three co-crystal structures. The solvent-accessible surface area of a residue may be estimated using techniques well known in the art. Further, it is expected that substitutions to amino acids buried within the variable domains will be better tolerated if the side chain of the amino acid does not create steric hindrance with adjoining residues. For this reason, buried amino acids generally are substituted with amino acids with side chains of similar or smaller size. For example, a substitution of a buried Ile residue with a Leu, Val, Ala, or Gly is expected to be tolerated. Possible steric hindrance created by a substitution can be predicted by analysis of the three co-crystal structures. Further substitutions that are expected to be tolerated are those maintaining existing electrostatic interactions within the variable domains, e.g., dipole-dipole interactions, induced dipole interactions, hydrogen bonds, or ionic bonds.

Additional amino acid substitutions of variable domains include those expected to confer new useful properties to the antibodies or antigen-binding fragments thereof. For example, putative N-glycosylation sites in the VH and/or VL domains can be removed to prevent or reduce the formation of N-glycoforms. The amino-terminal residue can be substituted with a Gln residue to cause pyroglutamylation, which can decrease the number of charge variants. Amino acid substitutions can be used to lower the isoelectric point, which can decrease the rate of elimination of IgG polypeptide antibodies, for example.

Surface residues of variable domains can be substituted with Cys or Lys residues, for example, which then can be covalently modified and coupled to molecules conferring useful characteristics to the antibodies or antigen-binding fragments thereof, e.g., a detectable label, toxin, targeting moiety, or protein. For example, Cys residue can be coupled to a cytotoxic drug to form a drug conjugate. Cys residues also can be coupled to molecules that increase the serum half-life, e.g., polyethylene glycol (PEG) or serum albumin. Such amino acid modifications are reviewed in <NPL>, for example.

Detectable labels include radiolabels such as <NUM>I or <NUM>Tc, which may be attached to antibodies or antigen-binding fragments thereof using methods known in the art. Labels also include enzyme labels such as horseradish peroxidase. Labels further include chemical moieties such as biotin which may be detected via binding to a specific cognate detectable moiety, e.g., labeled avidin. Other moieties can be attached that facilitate purification. For example, antibodies or antigen-binding fragments thereof can be His-tagged using well-known methods of recombinant modification and expression.

The VH and VL domains of the scFv-Fc dimers are linked together by a linker, termed Linker1 herein. Linkers suitable for making an scFv fragment are well known in the art. See, e.g., <NPL>; <NPL>. This can be accomplished by fusing the encoding nucleic acids in-frame and expressing the fusion protein in a suitable host cell, for example. Suitable linkers include those of the [G<NUM>S]<NUM>-type. The [G<NUM>S]<NUM>-type linkers are composed of repeating units of glycine and serine residues. According to the present invention, linker1 comprises a sequence of SGGGSGGGGSGGGGS (SEQ ID NO: <NUM>) or GGGGSGGGGSGGGGS (SEQ ID NO: <NUM>). [G<NUM>S]<NUM>-type linkers have been widely used to link variable domains in an scFv structure, because the linkers are hypoallergenic and causes minimal conformational distortions to the variable domains. See, e.g., <NPL>.

In the scFv-Fc dimers, a short linker sequence, termed Linker2 herein, is inserted between the VL domain and the hinge. This linker sequence increases the flexibility of the scFv component with respect to the Fc component. According to the present invention, Linker2 has the sequence of GGSG (SEQ ID NO: <NUM>). Suitable modifications to the GGSG linker include substituting one to two amino acids from Gly to Ser or vice versa.

The hinge region is a flexible domain that joins the scFv portion to the Fc region. The flexibility of the hinge region in IgG and IgA molecules allows the Fab arms to adopt a wide range of angles, permitting binding to epitopes spaced variable distances apart. The hinge region comprises an amino acid sequence from a human IgG1 hinge region comprising SEQ ID NO: <NUM>. The hinge from a human IgG1 contains two Cys residues, which can form disulfide bonds with the Cys residues of the hinge on the corresponding monomer. The human IgG1 hinge portion that forms the disulfide bonds contains the amino acid sequence CPPCP (SEQ ID NO: <NUM>). Variants of a human IgG1 hinge may comprise this sequence.

The scFv component is fused in frame to an Fc region, which forms the Fc component of the dimer. Fc regions are those from human IgG1, as set forth in SEQ ID NO: <NUM>, or IgG4, as set forth in the CH<NUM> and CH<NUM> domains of SEQ ID NO: <NUM>. The Fc region of an antibody mediates its serum half-life and effector functions, such as complement-dependent cytotoxicity (CDC), antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cell phagocytosis (ADCP).

Modifications can be made to the hinge and Fc region to improve various properties of the scFv-Fc dimers. For example, one, two, three, four, five or up to ten amino acids of a naturally occurring human Fc region can be modified, in addition to modifications of the hinge region. For example, the Fc region can be modified to increase the serum half-life of the scFv-Fc dimer. The half-life of an IgG depends on its pH-dependent binding to the receptor FcRn. FcRn, which is expressed on the surface of endothelial cells, binds the IgG in a pH-dependent manner and protects it from degradation. Mutations located at the interface between the CH<NUM> and CH<NUM> domains, for example, have been shown to increase the binding affinity to FcRn and the half-life of IgG1 in vivo. Such modifications are reviewed in <NPL>; and<NPL>, for example.

Other modifications to the hinge and/or Fc region can increase or reduce effector functions. The four human IgG isotypes bind the activating Fcy receptors (FcyRI, FcyRIIa, FcyRIIIa), the inhibitory FcyRIIb receptor, and the first component of complement (C1q) with different affinities, resulting in different effector functions. Binding of IgG to the FcyRs or C1q, for example, depends on residues located in the IgG hinge region and CH<NUM> domain. Single or multiple amino acid substitutions of these residues can affect effector function by modulating the IgG interaction with FcyRs or C1q. Other substitutions are known to affect effector function. These modifications are reviewed in <NPL>, for example.

Representative modifications of the hinge and/or Fc region are summarized in Table <NUM>.

Further, recombinant amino acid modifications can be used to decrease structural homogeneity of the expressed polypeptides. A representative example is <NPL>, which discloses Cys to Ser substitutions in the IgG4 hinge region that reduce the disulfide bond heterogeneity and increase Fab domain thermal stability. Similarly, <NPL> disclose engineering the IgG2 hinge region to limit disulfide bond scrambling and the formation of structural isomers in therapeutic applications. Amino acid modifications to a CH3 domain also can be used to delete carboxy-terminal Lys residues to decrease the number of charge variants. Amino acid modifications also can be used to improve the pharmacological function of recombinant antibodies or antigen-binding fragments thereof. For example, amino acid modifications can be used to increase complement activation, enhance antibody-dependent cellular cytotoxicity (ADCC) by increasing FcyRIIIA binding or decreasing FcyRIIIB binding, and/or increase serum half-life by increasing FcRn binding. Such amino acid modifications are reviewed in<NPL>, for example.

Also disclosed are nucleic acids encoding scFv-Fc dimers. The isolated nucleic acid may be a synthetic DNA, a non-naturally occurring mRNA, or a cDNA, for example. Examples include the nucleic acids encoding the VH and VL domains set forth in SEQ ID NOS: <NUM>, <NUM>, <NUM>, and <NUM> of <CIT>. Additional nucleic acids include the sequence set forth in SEQ ID NO: <NUM>, which encodes the diabody-5aa set forth in SEQ ID NO: <NUM>, and the sequence set forth in SEQ ID NO: <NUM>, which encodes the leucine zipper peptide-derived dimer having the amino acid sequence set forth in SEQ ID NO: <NUM>. Additional nucleic acids include the sequence set forth in SEQ ID NO: <NUM>, which encodes CAT191(scFv-Fc), which has the amino acid sequence set forth in SEQ ID NO: <NUM>. The nucleic acid may be inserted within a plasmid, vector, or transcription or expression cassette. The nucleic acids encoding the scFv-Fc dimers may be made and the expressed antibodies may be tested using conventional techniques well known in the art, such as disclosed in <NPL>.

A recombinant host cell may comprise one or more constructs above. Methods of preparing scFv-Fc dimers comprise expressing the encoding nucleic acid in a host cell under conditions to produce the scFv-Fc dimers, and recovering the antibodies. The process of recovering the antibodies may comprise isolation and/or purification of the antibodies. The method of production may comprise formulating the antibodies into a composition including at least one additional component, such as a pharmaceutically acceptable excipient.

The term "recombinant host cell" (or simply "host cell"), as used herein, is intended to refer to a cell into which exogenous DNA has been introduced. It should be understood that such terms are intended to refer not only to the particular subject cell, but, to the progeny of such a cell. Because certain modifications may occur in succeeding generations due to either mutation or environmental influences, such progeny may not, in fact, be identical to the parent cell, but are still included within the scope of the term "host cell" as used herein. Preferably host cells include prokaryotic and eukaryotic cells selected from any of the Kingdoms of life. Preferred enkaryotic cells include protist, fungal, plant and animal cells. Most preferably host cells include but are not limited to the prokaryotic cell line E. Coli; mammalian cell lines CHO, HEK <NUM> and COS; the insect cell line Sf9; and the fungal cell Saccharomyces cerevisiae.

Suitable vectors comprising a nucleic acid encoding scFv-Fc dimers can be chosen or constructed, containing appropriate regulatory sequences, including promoter sequences, terminator sequences, polyadenylation sequences, enhancer sequences, marker genes and other sequences as appropriate. Vectors may be plasmids, phage, phagemids, adenoviral, AAV, lentiviral, for example. Techniques and protocols for manipulation of nucleic acid, for example in preparation of nucleic acid constructs, mutagenesis, sequencing, introduction of DNA into cells, and gene expression, are well known in the art.

The term "vector", as used herein, is intended to refer to a nucleic acid molecule capable of transporting another nucleic acid to which it has been linked. One type of vector is a "plasmid", which refers to a circular double stranded DNA loop into which additional DNA segments may be ligated. Another type of vector is a viral vector, wherein additional DNA segments may be ligated into the viral genome. Certain vectors are capable of autonomous replication in a host cell into which they are introduced (e.g., bacterial vectors having a bacterial origin of replication and episomal mammalian vectors). Other vectors (e.g., non-episomal mammalian vectors) can be integrated into the genome of a host cell upon introduction into the host cell, and thereby are replicated along with the host genome. Moreover, certain vectors are capable of directing the expression of genes to which they are operatively linked. Such vectors are referred to herein as "recombinant expression vectors" (or simply, "expression vectors"). In general, expression vectors of utility in recombinant DNA techniques are often in the form of plasmids. In the present specification, "plasmid" and "vector" may be used interchangeably as the plasmid is the most commonly used form of vector. However, the invention is intended to include such other forms of expression vectors, such as viral vectors (e.g., replication defective retroviruses, adenoviruses and adena-associated viruses), which serve equivalent functions.

Introducing such nucleic acids into a host cell can be accomplished using techniques well known in the art. For eukaryotic cells, suitable techniques may include calcium phosphate transfection, DEAE-Dextran, electroporation, liposome-mediated transfection, and transduction using retroviruses or other viruses, for example. For bacterial cells, suitable techniques may include calcium chloride transformation, electroporation, and transfection using bacteriophage. The introduction may be followed by causing or allowing expression from the nucleic acid, e.g. by culturing host cells under conditions for expression of the gene. For example, the nucleic acid can be integrated into the genome, e.g., chromosome, of the host cell. Integration may be promoted by inclusion of sequences which promote recombination with the genome, in accordance with standard techniques.

Systems for cloning and expression of a polypeptide in a variety of different host cells are well known. Suitable host cells include bacteria, mammalian cells, plant cells, insect cells, fungi, yeast and transgenic plants and animals. Mammalian cell lines available in the art for expression of a heterologous polypeptide include Chinese hamster ovary (CHO) cells, HeLa cells, baby hamster kidney cells, mouse melanoma cells, rat myeloma cells, human embryonic kidney cells, e.g., HEK293 cells, human embryonic retina cells, and many others. The expression of antibodies and antibody fragments in prokaryotic cells, such as E. coli, is well established in the art. For a review, see for example, <NPL>). Expression in cultured eukaryotic cells is also available to those skilled in the art, as reviewed in <NPL>, for example.

scFv-Fc dimers may be glycosylated, either naturally or the choice of expression host, e.g., CHO, HEK293, or NSO (ECACC <NUM>) cells, or they may be unglycosylated, for example if produced by expression in a prokaryotic cell. Glycosylation may also be intentionally altered, for example by inhibiting fucosylation, in order to increase ADCC activity of the resulting scFv-Fc dimer.

The scFv-Fc dimers may be for use in the treatment of the human or animal body, such as a treatment (which may include prophylactic treatment) of a disease or disorder in a human patient, which comprises administering an effective amount to treat the patient. In accordance with the present invention, treatable conditions include any in which TGFβ1 plays a role, e.g., a fibrotic disease, cancer, an immune-mediated disease, diffuse cutaneous systemic sclerosis, bone remodeling disease, and a kidney disease.

Antibodies specific for human TGFβ1 have been shown to be effective in animal models for the treatment of TGFβ1 glomerulonephritis (<NPL>), neural scarring (<NPL>), dermal scarring (<NPL>; <NPL>; <NPL>), and pulmonary fibrosis (<NPL>). Further, antibodies to TGFβ1, <NUM>, and <NUM> have been shown to be effective in models of lung fibrosis, radiation induced fibrosis (<CIT>), myelofibrosis, burns, Dupuytren's contracture, gastric ulcers, and rheumatoid arthritis (<NPL>).

The scFv-Fc dimers are useful to treat a disease and condition resulting directly or indirectly from TGFβ1 activity. The scFv-Fc dimers may selectively inhibit the activity of a human TGFβ1 isoform in vitro or in vivo. Activities of TGFβ1 isoforms include, but are not limited to, TGFβ-mediated signaling, extracellular matrix (ECM) deposition, inhibiting epithelial and endothelial cell proliferation, promoting smooth muscle proliferation, inducing Type III collagen expression, inducing TGF-β, fibronectin, VEGF, and IL-<NUM> expression, binding Latency Associated Peptide, tumor-induced immunosuppression, promotion of angiogenesis, activating myofibroblasts, promotion of metastasis, and inhibition of NK cell activity. For example, the scFv-Fc dimers are useful to treat focal segmental glomerulosclerosis (FSGS), hepatic fibrosis (HF), acute myocardial infarction (AMI), idiopathic pulmonary fibrosis (IPF), scleroderma (SSc), and Marfan Syndrome.

The scFv-Fc dimers are useful to treat diseases and conditions including, but not limited to, a fibrotic diseases (such as glomerulonephritis, neural scarring, dermal scarring, pulmonary fibrosis, lung fibrosis, radiation induced fibrosis, hepatic fibrosis, myelofibrosis), burns, immune mediated diseases, inflammatory diseases (including rheumatoid arthritis), transplant rejection, cancer, Dupuytren's contracture, and gastric ulcers. They are also useful for treating, preventing and reducing the risk of occurrence of renal insufficiencies including but not limited to: diabetic (type I and type II) nephropathy, radiation-induced nephropathy, obstructive nephropathy, diffuse systemic sclerosis, pulmonary fibrosis, allograft rejection, hereditary renal disease (e.g., polycystic kidney disease, medullary sponge kidney, horseshoe kidney), glomerulonephritis, nephrosclerosis, nephrocalcinosis, systemic lupus erythematosus, Sjogren's syndrome, Berger's disease, systemic or glomerular hypertension, tubulointerstitial nephropathy, renal tubular acidosis, renal tuberculosis, and renal infarction. In particular, they are useful when combined with antagonists of the renin-angiotensin-aldosterone system including, but not limited to: renin inhibitors, angiotensin-converting enzyme (ACE) inhibitors, Ang II receptor antagonists (also known as "Ang II receptor blockers"), and aldosterone antagonists. Methods for using scFv-Fc dimers in combination with such antagonists are set forth in <CIT>, for example.

The scFv-Fc dimers also are useful to treat diseases and conditions associated with the deposition of ECM, including, systemic sclerosis, postoperative adhesions, keloid and hypertrophic scarring, proliferative vitreoretinopathy, glaucoma drainage surgery, corneal injury, cataract, Peyronie's disease, adult respiratory distress syndrome, cirrhosis of the liver, post myocardial infarction scarring, post angioplasty restenosis, scarring after subarachnoid hemorrhage, multiple sclerosis, fibrosis after laminectomy, fibrosis after tendon and other repairs, scarring due to tattoo removal, biliary cirrhosis (including sclerosing cholangitis), pericarditis, pleurisy, tracheostomy, penetrating central nervous system injury, eosinophilic myalgic syndrome, vascular restenosis, veno-occlusive disease, pancreatitis and psoriatic arthropathy.

The scFv-Fc dimers further are useful to promote re-epithelialization in diseases and conditions such as venous ulcers, ischaemic ulcers (pressure sores), diabetic ulcers, graft sites, graft donor sites, abrasions and burns, diseases of the bronchial epithelium, such as asthma, ARDS, diseases of the intestinal epithelium, such as mucositis associated with cytotoxic treatment, esophageal ulcers (reflux disease), stomach ulcers, small intestinal and large intestinal lesions (inflammatory bowel disease).

The scFv-Fc dimers also may be used to promote endothelial cell proliferation, for example, in stabilizing atherosclerotic plaques, promoting healing of vascular anastomoses, or to inhibit smooth muscle cell proliferation, such as in arterial disease, restenosis and asthma.

The scFv-Fc dimers are useful to enhance the immune response to macrophage-mediated infections. They are also useful to reduce immunosuppression caused, for example, by tumors, AIDS, or granulomatous diseases. The scFv-Fc dimers are useful to treat hyperproliferative diseases, such as cancers including, but not limited to, breast, prostate, ovarian, stomach, renal, pancreatic, colorectal, skin, lung, cervical and bladder cancers, glioma, mesothelioma, as well as various leukemias and sarcomas, such as Kaposi's sarcoma, and are useful to treat or prevent recurrences or metastases of such tumors. The scFv-Fc dimers of the invention also are useful to inhibit cyclosporin-mediated metastases.

In the context of cancer therapy, "treatment" includes any medical intervention resulting in the slowing of tumor growth or reduction in tumor metastases, as well as partial remission of the cancer in order to prolong life expectancy of a patient.

The treatments described herein may comprise administering a scFv-Fc dimer or pharmaceutical compositions comprising the scFv-Fc dimer. The scFv-Fc dimers may be used in the manufacture of a medicament for administration. For example, a method of making a medicament or pharmaceutical composition comprises formulating a scFv-Fc dimer with a pharmaceutically acceptable excipient. A composition may be administered alone or in combination with other treatments, either simultaneously or sequentially dependent upon the condition to be treated.

Administration is preferably in a "therapeutically effective amount" sufficient to show benefit to a patient. Such benefit may be at least amelioration of at least one symptom of a particular disease or condition. The actual amount administered, and rate and time-course of administration, will depend on the nature and severity of the disease or condition being treated. Prescription of treatment, e.g., decisions on dosage etc., may be determined based on preclinical and clinical studies the design of which is well within the level of skill in the art.

The precise dose will depend upon a number of factors, including whether the scFv-Fc dimer is for diagnosis or for treatment, the size and location of the area to be treated, and the nature of any detectable label or other molecule attached to the scFv-Fc dimer. A typical dose of a scFv-Fc dimer, for example, can be in the range <NUM>µg to <NUM> gram for systemic applications, and <NUM>µg to <NUM> for topical applications. The dose for a single treatment of an adult patient may be adjusted proportionally for children and infants. Treatments may be repeated at daily, twice-weekly, weekly, monthly or other intervals, at the discretion of the physician. Treatment may be periodic, and the period between administrations is about two weeks or more, preferably about three weeks or more, more preferably about four weeks or more, or about once a month.

Dose levels of about <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> per kg body weight of the patient are expected to be useful and safe. For example, <NUM>-<NUM>/kg in rat and mouse has been an effective dose in an acute setting. Therefore, for long-term dosing, <NUM>-<NUM>/kg may be administered to humans, based on an expected half-life of <NUM> days. Doses may be sufficient for efficacy, while low enough to facilitate optimal administration. For example, a dose of less than <NUM> facilitates subcutaneous administration. Intravenous administration may be used as the route of delivery for severe diseases, where high doses and the long dosing intervals may be required. Subcutaneous injection can increase the potential immune response to a product. Local administration for localized disease can reduce the amount of administered product and increase the concentration at the site of action, which can improve safety.

The scFv-Fc dimers of the invention may be administered by injection, for example, subcutaneously, intravenously, intracavity (e.g., after tumor resection), intralesionally, intraperitoneally, or intramuscularly. ScFv-Fc dimers also may be delivered by inhalation or topically (e.g., intraocular, intranasal, rectal, into wounds, on skin), or orally.

A scFv-Fc dimer will usually be administered in the form of a pharmaceutical composition, which may comprise at least one component in addition to the scFv-Fc dimer. Thus pharmaceutical compositions may comprise a pharmaceutically acceptable excipient, carrier, buffer, stabilizer or other materials well known to those skilled in the art. Such materials should be non-toxic and should not interfere with the efficacy of the active ingredient. Such materials could include, for example, any and all solvents, dispersion media, coatings, antibacterial and antifungal agents, isotonic, and absorption delaying agents. Some examples of pharmaceutically acceptable carriers are water, saline, phosphate buffered saline, dextrose, glycerol, ethanol, and the like, as well as combinations thereof. In many cases, it will be preferable to include isotonic agents, for example, sugars, polyalcohols, such as mannitol, sorbitol, or sodium chloride in the composition. Additional examples of pharmaceutically acceptable substances are wetting agents or auxiliary substances, such as emulsifying agents, preservatives, or buffers, which increase the shelf life or effectiveness.

The precise nature of the carrier or other material will depend on the route of administration. For intravenous injection, or injection at the site of affliction, the active ingredient will be in the form of a parenterally acceptable aqueous solution which is pyrogen-free and has suitable pK, isotonicity, and stability. Those of relevant skill in the art are well able to prepare suitable solutions using, for example, isotonic vehicles such as sodium chloride injection, Ringer's injection, and lactated Ringer's injection. Preservatives, stabilizers, buffers, antioxidants, and/or other additives may be included.

A scFv-Fc dimer may be formulated in liquid, semi-solid, or solid forms, such as liquid solutions (e.g., injectable and infusible solutions), dispersions or suspensions, powders, liposomes, and suppositories. The preferred form depends on the intended mode of administration, the therapeutic application, the physicochemical properties of the molecule, and the route of delivery. Formulations may include excipients, or combinations of excipients, for example: sugars, amino acids and surfactants. Liquid formulations may include a wide range of scFv-Fc dimer concentrations and pH. Solid formulations may be produced by lyophilization, spray drying, or drying by supercritical fluid technology, for example.

Therapeutic compositions can be formulated as a solution, microemulsion, dispersion, liposome, or other ordered structure suitable to high drug concentration. Sterile injectable solutions can be prepared by incorporating the scFv-Fc dimer in an appropriate solvent with one or a combination of ingredients enumerated above, followed by filtered sterilization. Generally, dispersions are prepared by incorporating the active compound into a sterile vehicle that contains a basic dispersion medium and other ingredients from those enumerated above. In the case of sterile powders for the preparation of sterile injectable solutions, the preferred methods of preparation are vacuum drying and freeze-drying that yields a powder of the active ingredient plus any additional desired ingredient from a previously sterile-filtered solution thereof. The proper fluidity of a solution can be maintained, for example, by using a coating such as lecithin, by maintaining the particle size of a dispersion, or by using surfactants. Prolonged absorption of injectable compositions can be brought about by including in the composition an agent that delays absorption, for example, monostearate salts and gelatin.

The active compound may be prepared with a carrier that will protect the scFv-Fc dimer against rapid release, such as a controlled release formulation, including implants, transdermal patches, and microencapsulated delivery systems. Biodegradable, biocompatible polymers can be used, such as ethylene vinyl acetate, polyanhydrides, polyglycolic acid, collagen, polyorthoesters, and polylactic acid. Many methods for the preparation of such formulations are patented or generally known to those skilled in the art.

A method of using a scFv-Fc dimer may comprise causing or allowing binding to TGFβ. Such binding may take place in vivo, e.g., following administration of a scFv-Fc dimer to a patient, or it may take place in vitro, e.g., in ELISA, Western blotting, immunocytochemistry, immunoprecipitation, affinity chromatography, or cell based assays, or in ex vivo based therapeutic methods, e.g., methods in which cells or bodily fluids are contacted ex vivo with a scFv-Fc dimer and then administered to a patient.

A kit comprising a scFv-Fc dimer is also disclosed. The scFv-Fc dimer may be labeled to allow its reactivity in a sample to be determined. Kits may be employed in diagnostic analysis, for example. A kit may contain instructions for use of the components. Ancillary materials to assist in or to enable performing such a method may be included within the kit.

The reactivity of a scFv-Fc dimer in a sample may be determined by any appropriate means, e.g., radioimmunoassay (RIA). Radioactively labeled antigen may be mixed with unlabeled antigen (the test sample) and allowed to bind to the scFv-Fc dimer. Bound antigen is physically separated from unbound antigen and the amount of radioactive antigen bound to the scFv-Fc dimer is determined. A competitive binding assay also may be used with non-radioactive antigen, using an antigen or an analogue linked to a reporter molecule. The reporter molecule may be a fluorochrome, phosphor, or dye. Suitable fluorochromes include fluorescein, rhodamine, phycoerythrin and Texas Red. Suitable chromogenic dyes include diaminobenzidine.

Other reporters include macromolecular colloidal particles or particulate material such as latex beads that are colored, magnetic or paramagnetic, and biologically or chemically active agents that can directly or indirectly cause detectable signals to be visually observed, electronically detected or otherwise recorded. These molecules may be enzymes that catalyze reactions that develop or change colors or cause changes in electrical properties, for example. They may be molecularly excitable, such that electronic transitions between energy states result in characteristic spectral absorptions or emissions. They may include chemical entities used in conjunction with biosensors. Biotin/avidin or biotin/streptavidin and alkaline phosphatase detection systems may be employed. The signals generated by antibody-reporter conjugates may be used to derive quantifiable absolute or relative data of the relevant antibody binding in samples.

The scFv-Fc dimer may also be used for measuring antigen levels in a competition assay. The scFv-Fc dimer can be linked to a reporter molecule so that a physical or optical change occurs on binding, for example. The reporter molecule may directly or indirectly generate detectable, and preferably measurable, signals. The reporter molecules may be linked directly or indirectly, covalently, e.g., via a peptide bond or non-covalently. The scFv-Fc dimer and a protein reporter may be linked by a peptide bond and recombinantly expressed as a fusion protein.

Further aspects and embodiments of the present invention will be apparent to those skilled in the art in the light of the present disclosure, including the following experimental exemplification.

CAT192(IgG4) (metelimumab) is a human IgG4 monoclonal antibody that selectively neutralizes TGF-β1. TGFβ1 (<NUM>-600RU) was immobilized to a CM5 chip on Biacore using NHS/EDC chemistry. Various amounts of CAT192(IgG4) were injected over the surface to monitor the binding to TGFβ1 determined by surface plasmon resonance. The data were analyzed with a <NUM>:<NUM> binding model to determine binding constants. CAT192(IgG4) was found to bind TGFβ1 with relatively low affinity as determined by surface plasmon resonance, when compared to the binding by the parental CAT191scFv as shown in <FIG>. CAT192(IgG4) also showed a relatively low efficacy (IC50 = ~<NUM>) in an A549 cell-based potency assay, which measured inhibition of TGFβ1-stimulated IL-<NUM> production. Representative results of an A549 assay are shown in <FIG>. The A549 assay was conducted according to the procedure disclosed in <NPL>. While an apparent dissociation constant of ~<NUM> showed specific binding to TGFβ1, therapeutic applications of CAT192 (IgG4) would benefit from a higher relative potency.

CAT192(IgG4) affinity can be slightly enhanced by certain denaturing conditions, suggesting that antibody folding may have caused the loss of affinity during the conversion of scFv to IgG4. IgG4 folding has been proposed to be unique (<NPL>). The Fab arm exchange in IgG4 and the interaction of Fabs with Fc CH2 domain may possibly explain this loss of affinity by CAT192(IgG4). Therefore, CAT192 was remodeled to produce the IgG1 version by replacing IgG4 Fc (CH1, CH2 and CH3 domains) with the consensus IgG1 sequence. The DNA coding the CAT192 (IgG1) was synthesized from GeneArt and subcloned into expression vector pCEP4(-E+I)Dest.

CAT192(IgG1) was produced from HEK293 transfection and purified with Protein A column. Remodeling CAT192 from IgG4 to IgG1, however, did not increase its affinity. Fab fragments generated from the IgG1 and IgG4 did not increase its affinity either. It was concluded that the high affinity of CAT191(scFv) (SEQ ID NO: <NUM>) was lost during conversion to a full-length antibody format, whether it was a IgG1 or IgG4. This was unexpected, because scFv components obtained from a library are often engineered to a full-length IgG format for therapeutic development.

CAT191(scFv) (SEQ ID NO: <NUM>) was found to bind TGFβ1 with high affinity, using surface plasmon resonance, but CAT191(scFv) lacked the avidity needed for effective neutralization of TGFβ1. Accordingly, various other formats were tested, using the scFv component as a basic building block. General formats of antibody fragments, including the tested formats, are depicted in FIG.

Tested formats included a diabody, a peptide-derived dimer (e.g., a leucine zipper peptide-derived dimer), and an scFv-Fc dimer. scFv CAT191 diabody had the (Gly4Ser)<NUM>-type linker replaced with a short 5aa linker (GSSGG) (SEQ ID NO: <NUM>) to create a non-covalent divalent binder (diabody dimer). Each monomer had the sequence set forth in SEQ ID NO: <NUM>. Each monomer of the leucine zipper peptide-derived dimer had the sequence set forth in SEQ ID NO: <NUM>. Finally, each monomer of the scFv-Fc dimer had the sequence set forth in SEQ ID NO: <NUM>. The diabody and the peptide derived dimer were expressed in E. Coli and the scFv-Fc was expressed in HEK293 cells.

The leucine zipper peptide-derived dimer was difficult to express, and the partially purified dimer only showed intermediate affinity, as measured by surface plasmon resonance. The diabody (scFv 5aa) only showed intermediate affinity, but no avidity. By contrast, a scFv-Fc dimer produced from transient HEK293 transfection was found to bind to TGFβ1 specifically with high affinity and avidity. The binding results expressed as apparent dissociation constants obtained with surface plasmon resonance are summarized below in Table <NUM>.

The TGFβ1 neutralizing potency of various formats was also compared in the A549 cell-based bioassay. <FIG> shows the A549 bioassay results for the diabody ("scFv diabody 5aa"), CAT191(scFv) ("scFv"), the scFv-Fc dimer ("CAT191(scFv-Fc"), and CAT192(IgG4) ("CAT192"). As seen in <FIG>, the scFv-Fc dimer demonstrated an apparent dissociation constant in this assay over four orders of magnitude lower than CAT192 (~<NUM>-<NUM> nM versus ~<NUM><NUM> nM).

CAT191(scFv-Fc) was cloned and produced in larger scale in CHO cells. CAT191 scFv-Fc coding sequence was PCR amplified from a pCEP4 based expression vector using a gene specific forward and reverse primer set. As part of the PCR amplification the following changes were introduced to the CAT191 scFv-Fc coding sequence: <NUM>) addition of endonuclease sites at the <NUM>' and <NUM>' ends, <NUM>) addition of Kozak consensus sequence immediately upstream of the start codon, <NUM>) change of the "TAG" stop codon to "TAA", and <NUM>) mutation of the thymidine <NUM> nucleotides upstream of the stop codon to a guanosine thus eliminating an endogenous splice donor site. The splice donor site mutation did not result in an amino acid change.

The PCR amplified CAT191 coding sequence was subcloned into a shuttle vector to facilitate sequence verification and molecular cloning. After sequence verification, the CAT191 coding sequence was cloned into Genzyme expression vectors pGZ600 and pGZ620. Both vectors used the hamster β-actin promoter to drive expression of the CAT191 transgene. They also contained the DHFR selectable marker that was driven by a separate promoter (SV40) to enable selection in CHO cells. CHO-8D6 host cell line was transfected with either the pGZ600-CAT191 or pGZ620-CAT191 expression plasmid. Following a brief recovery period, the transfected cells were placed into nucleotide-deficient growth medium for selection to generate pools of stable transfectants. After pools recovered from selection, a second round of selection was performed in the presence of <NUM> methotrexate. The CHO pools selected this way was scaled up and the conditioned media was used for purification using Protein A column.

The CHO cell-produced protein was characterized by SDS-PAGE, Biacore binding, SEC-HPLC, and the A549 cell potency assay. The results confirmed that the scFv-Fc dimer had a higher affinity and potency, and it specifically neutralized TGFβ1. The potency compared favorably to the pan-specific GC1008 antibody (<FIG>).

The circulation half-life of CAT191(scFv-Fc) was tested in a mouse model using the study design depicted in Table <NUM>.

Blood was drawn from the retro-orbital plexus at the specified times after intraperitoneal (IP) or intravenous (IV) administration. Approximately <NUM>µL of whole blood was collected into hematocrit tubes and processed for serum. All samples was stored at -<NUM> until analysis. The CAT191(scFv-Fc) concentration was determined by ELISA. The results of this pharmacokinetic study are depicted in <FIG>. The results suggested a circulation half-life of <NUM>-<NUM> days, much longer than that for a typical scFv molecule, which is several hours.

Claim 1:
An isolated binding protein that selectively binds human TGFβ1, wherein said binding protein is a homodimer of a polypeptide chain having the formula of, from N-terminus to C-terminus:
VH domain-linker <NUM> -VL domain-linker2 -hinge -Fc region,
wherein
the VH domain comprises SEQ ID NO: <NUM> and the VL domain comprises SEQ ID NO: <NUM>;
the linker1 comprises SEQ ID NO: <NUM> or SEQ ID NO: <NUM>;
the linker2 comprises SEQ ID NO:<NUM> or a variant thereof, wherein the variant differs from SEQ ID NO:<NUM> by having up to two amino acid substitutions from glycine to serine or from serine to glycine; and
the hinge comprises an amino acid sequence from a human IgG1 hinge region comprising the amino acid sequence of SEQ ID NO:<NUM>; and
the Fc region is a human IgG1 or a human IgG4 Fc region.