Compositions and uses thereof

Abstract

The invention relates to therapeutic agents e.g. polypeptides that bind truncated soluble endoglin, including immunoglobulins (e.g. antibodies), the agents comprising mutations which reduce maternofoetal transfer, as well as nucleic acids encoding said polypeptides, vectors, pharmaceutical compositions and methods of making and use of the polypeptides, including methods of treatment.

Description

[0001] COMPOSITIONS AND USES THEREOF

[0002] FIELD

[0003] The present disclosure relates to molecules, in particular polypeptides, including but not limited to immunoglobulins (e.g., antibodies, e.g. monoclonal antibodies), comprising a variant IgG Fc domain comprising mutations that result in reduced maternofetal transfer. The present disclosure relates in particular to monoclonal antibodies that are useful in therapy and / or prophylaxis, in particular in relation to disorders and diseases associated with pregnancy. The disclosure also comprises nucleic acids encoding such polypeptides, expression vectors, host cells, and methods of making and using them, including therapeutic and diagnostic compositions, formulations, and kits.

[0004] BACKGROUND

[0005] Drugs administered to the mother can be dangerous for the fetus thus making the development of new therapeutics very challenging. Animal models that reflect the same physiology and pathology as human pregnancy are very limited and therapeutic effects in models do not well reflect those in human. The maternal metabolism can change during different stages of pregnancy, and in pathological conditions, meaning that the exposure to the fetus is variable and difficult to define. The susceptibility of the fetus also changes during the progression of development and growth. Furthermore, the means to monitor the safety of the fetus during pregnancy are very limited and drug-related adverse effects cannot easily be detected or characterised. Taken together these limitations and safety concerns mean that very few drugs are approved for use during pregnancy, very few are in development and the prospects for new treatments are severely limited.

[0006] As such, there is an unmet need for a new class of therapeutic drugs capable of addressing the medical conditions of pregnant women (for instance, pre-existing auto-immune disorders or pregnancy-related hypertension or pre-eclampsia / eclampsia) while remaining safe for the fetus.

[0007] This important problem is solved by the present invention by providing polypeptides, in particular antibodies, which are not transported across the placenta thus allowing the development of new drugs which can harness the broad therapeutic applicability and specificity of antibodies without concern for the safety of the fetus. Purposely reducing the placental transfer ability of a polypeptide to solve the above-mentioned problem has never been attempted in the past. Placental transfer has been studied extensively (as you will see below) but always in an attempt to facilitate or increase placental transfer rather than inhibiting it.

[0008] The placenta functions to exchange all that the early embryo and developing fetus requires for life and to remove the waste products from fetal metabolism. It is selective in allowing the exchange of dissolved gasses, small molecules and nutrients but provides an almost complete barrier to larger molecules and proteins thus preventing the mixture of maternal and fetal blood components.

[0009] In women, maternal antibodies of the IgG sub-class can cross the placenta in increasing amounts from around week 20 of pregnancy. This permits the transfer of maternal antibodies which provide a level of immunity to the fetus until its own immune system can develop. The efficiency of antibody transfer depends on the IgG subclass, with IgG-1 most efficiently transferred, and relies on an active process since administered therapeutic antibodies can be measured at higher concentration (1.5 to 4 fold higher) in the fetal circulation compared to the mother (Pham-Huy, A., et al, From mother to baby: antenatal exposure to monoclonal antibody biologies. Expert Review of Clinical Immunology. Taylor and Francis Ltd; 2019, 15: 221-9).

[0010] Transport of antibodies from mother to fetus is not always beneficial. The presence of autoantibodies to Ro (SS-A) and La (SS-B) in pregnant women with or without a full-blown autoimmune disease conveys a substantially increased risk of the neonatal lupus syndrome. Similarly, prospective studies of anticardiolipin autoantibodies in pregnant women have shown a significantly increased frequency of mid-trimester fetal loss in women with high levels of such autoantibodies (Elkon K., et al, Nature and functions of autoantibodies. Nat. Clin. Pract. Rheumatol. 2008, 9:491-8).

[0011] The majority of therapeutic antibodies in clinical use are of the IgG class and there are many reports of placental transfer (Pham-Huy, K.A., et al, The use and impact of monoclonal antibody biologies during pregnancy. CM A J 2021, 193: 1129-1136). Adulimumab, for example, is found at levels up to 1.5 times higher in the neonate compared to the maternal circulation and the drug can persist for 3-5 months in the infant circulation. The transfer of therapeutic antibodies across the placenta is a real medical concern because of known dangers for the fetus or a lack of information about the risk to the fetus. An example of known risk is bevacizumab which inhibits angiogenesis and causes fetal defects in animals and according to the drug label is not recommended during pregnancy. The risk of a low incidence but serious adverse effect for the fetus following treatment of pregnant women is very difficult to assess and today only products that have been in long-term use with large registry databases can be assessed for fetal safety. The risk of adverse effects due to fetal exposure limits the use of therapeutic antibodies in pregnant women meaning that treatment for an ongoing condition of the mother is normally halted around the end of the first trimester, after which significant maternal antibody transfer occurs, unless the benefit to the mother outweighs the risk to the fetus. Currently developed therapeutic antibodies can thus only be administered to pregnant women with acceptance of fetal risk which severely limits the available antibody treatments for pregnant women.

[0012] Natural IgG antibodies are tetrameric proteins comprising two identical heavy chains and two identical light chains with the variable regions of each heavy chain / light chain pair juxtaposed to form two identical antigen binding sites. The carboxy-terminal portion of the heavy chain regions, after the so-called ‘hinge region’, which are not paired with light chains and are linked to each other by disulphide bridges comprise the so-called Fc region. The Fc region contains binding sites which interact with a range of different Fey receptors and the FcRn receptor as described below. Transfer of IgG across the maternal syncytiotrophoblast membrane and the fetal placental endothelial cell layer is a complex, incompletely understood process and the role of different Fc receptors is debated.

[0013] The FcRn receptor is known to play a major role in placental transfer of IgG. This was demonstrated, although not with the purpose of providing a polypeptide according to the invention, by introducing single mutations in the antibody Fc region to interfere with binding to the FcRn receptor:

[0014] Disruption of Fc - FcRn binding by substitution of histidine for alanine at amino acid 435 was shown to reduce materno-fetal transfer in both pregnant mice and across ex-vivo human placenta by as much as 90% (Firan, M., et al, The MHC class I-related receptor, FcRn, plays an essential role in the materno-fetal transfer of gamma-globulin in humans. Int. Immunol. 2001, 13: 993-1002). Single FcRn mutations I253A, H310A or H435A reduce materno-fetal transfer in pregnant mice by 80 to 90% but were not tested for the effects on materno-fetal transfer in combination (see US 6,277,375 Bl).

[0015] A modified version of bevacizumab with the H435A Fc mutation was tested in a rat model and found to block materno-fetal transfer by no more than 90% (Thorn, M. , et al, Embryo- fetal transfer of bevacizumab (A vastin) in the rat over the course of gestation and the impact of neonatal Fc receptor (FcRn) binding. Birth Defects Res B Dev Reprod. Toxicol. 2012, 95: 363-75)

[0016] Although FcRn plays a major role in IgG transfer there are no studies showing that the inhibition of maternofetal transfer following modifications to FcRn binding is reduced by more than 90%. This indicates that other receptors must be involved. Furthermore, FcRn is not present on the fetal endothelium - which would be expected for a FcRn-only transport process - and maternofetal IgG selective transfer depending on glycosylation or antigen specificity has been reported - which cannot be explained by the selectivity of FcRn binding. Thus, FcyR receptors Ila and Illb have been reported to play a role in maternofetal transfer of antibodies (Jennewein, M.F., et al, Fc Glycan-Mediated Regulation of Placental Antibody Transfer. Cell. 2019, 178: 202-215). Based on the current state of research it cannot be excluded that other FcyR, in addition to Ila and Illb, play a role in maternofetal transfer of IgG antibodies.

[0017] In the above cited prior-art, inhibition of maternofetal transfer by more than 90% has not been demonstrated and such level of inhibition would not be enough to provide a safe treatment for pregnant women.

[0018] SUMMARY

[0019] Development of any therapeutic for the treatment of pregnant women, or women who may become pregnant, faces major medical concerns due to fetal exposure and the possible consequences for safety. This important problem is solved herein by the design of antibodies which are not transported across the placenta allowing the development of new drugs which can harness the broad therapeutic applicability, specificity, and known manufacturing technologies of antibodies without concern for the safety of the fetus. Such ‘mother-only’ antibodies enable the creation of a brand-new class of therapeutics to address the unmet medical needs of pregnant women such as hypertension-related conditions and pre-eclampsia / eclampsia, and other disorders (diseases) of pregnancy.

[0020] It is also possible to develop antibodies, and other IgGFc containing molecules as described herein, for conditions not related to pregnancy which can still be used by women likely to become pregnant and during pregnancy.

[0021] It is therefore understood that the invention is not limited to any specific disease or treatment but provides a platform for the design of drugs, and drugs, with which pregnant women might be treated safely for a range of different disorders without risk of these harming the fetus or significantly reducing any risk to the fetus.

[0022] The present disclosure is directed to isolated binding molecules, such as antibodies, that selectively bind to a fragment of soluble Endoglin (sENG), with minimal binding to the membrane-associated Endoglin. In an embodiment, the sENG selective antibody is engineered in the Fc region to block maternal-foetal placental transfer, accelerate clearance of bound sENG and disable Fey receptor interactions.

[0023] Endoglin is expressed as a cell-surface transmembrane receptor predominantly localised on endothelial cells but is also evident on cells involved in haematopoiesis, implying a role in the development of individual cell lineages, and mature immune cells, macrophages, mast cells and T- cells, suggesting various roles in immune responses (Meurer, S. and Weiskirchen, R. Int. J. Mol. Sci. 202021: 9247-9274).

[0024] It is therefore desirable for a therapeutic agent for the treatment of diseases and conditions of pregnancy to specifically target sENG. The advantages of specifically targeting sENG include: not disrupting normal functions linked to membrane endoglin and reducing possible adverse sideeffects; not displacing bound ligands from the sENG binding site and thus not affecting the circulating levels of these ligands; and potentially reducing the amount of antibody sequestered by membrane endoglin and thus ineffective against sENG. Binding molecules of the present disclosure therefore target sENG and its role in the pathologies of pregnancy, without having an effect on the physiological activity of endoglin. Numerous studies report the development of monoclonal antibodies intended to bind to the membrane receptor and selected by the ability to bind cells which express membrane-spanning endoglin (see for e.g., W02010032059A3, WO2012149412A2 and W02010039873).

[0025] The term “sENG” usually refers to the full extracellular region of the membrane-spanning endoglin following proteolytic cleavage and release into the circulation. The sENG identified in the plasma of women experiencing preelampsia, fetal growth restriction or HELLP syndrome is of lower molecular weight compared to the released, full length extracellular domain. Therefore, the term “short sENG” is used herein to describe the truncated version of the molecule manifest in diseases and conditions of pregnancy.

[0026] Short sENG may be a group of molecules of similar molecular weight, judged to be around 15kDa smaller than the extracellular domain. Short sENG is a monomer caused by the removal of the carboxy-terminal sequences which, in the extracellular domain, are linked by one or more disulphide bridges.

[0027] Therefore, in one aspect, the present invention relates to an isolated binding molecule that specifically binds to short soluble endoglin (short sENG).

[0028] In one aspect, the invention relates to an isolated binding molecule for use in medicine in a pregnant woman, wherein the binding molecule specifically binds to short soluble endoglin (short sENG).

[0029] In one aspect, the invention relates to an isolated binding molecule for use in the treatment or prevention of a disorder of pregnancy in a pregnant woman, wherein the binding molecule specifically binds to short soluble endoglin (short sENG).

[0030] In one aspect, the invention relates to a method of treating a pregnant woman, the method comprising administering an effective amount of an isolated binding molecule, wherein the binding molecule specifically binds to short soluble endoglin (short sENG).

[0031] The binding molecule of the invention is preferably a polypeptide, and preferably an antibody, or a binding fragment thereof, that selectively binds to short sENG. In an embodiment, the binding molecule is a monoclonal antibody, or a fragment thereof, preferably a fully human or humanized monoclonal antibody. In order to make a monoclonal antibody selective for short sENG it is necessary to identify a binding site unique to the soluble molecule but inaccessible on the membrane-spanning endoglin. sENG is uniquely produced by the proteolytic cleavage of membrane-spanning endoglin and released as a disulphide-linked dimer (Saito, T., et al., Structural Basis of the Human Endoglin- BMP9 Interaction: Insights into BMP Signaling and HHT1. Cell Reports 2017 19: 1917-1928). However, short sENG from the plasma of preeclamptic women is a monomer and is truncated, compared to the monomer of the cleaved extra-cellular domain and henceforth referred to as ‘short sENG’ to distinguish from the disulphide-linked extracellular domain (see Lawera, A., et al., Role of soluble endoglin in BMP9 signalling. PNAS. 2019 116: 17800-17808, Figure IE). Evidently sENG, after release by cleavage from membrane-spanning endoglin is further truncated by proteolysis. Based on the molecular weight of the species identified in a preeclamptic woman’s plasma, it is predicted that the site of cleavage is between the ZP-N and ZP-C domains. This exposes a new surface of ZP-N which is hidden in the membrane-spanning endoglin and in the proteolytically cleaved extracellular domain but, uniquely, exposed in short sENG.

[0032] Therefore, one aspect of the invention is directed to the use of a short sENG polypeptide terminating after the ZP-N domain as an immunogen for the development of monoclonal antibodies.

[0033] The broad panel of monoclonal antibodies generated to this ZP-N immunogen can then selected to remove antibodies binding to cells that display membrane-spanning endoglin and positively selected for those binding to short sENG from the plasma of preeclamptic women. Such antibodies are thus capable of specifically binding to short sENG. Antibodies that are specific for short sENG can be humanised, sequence optimised and, following modification of the Fc region to block maternal-foetal placental transfer, accelerate clearance of bound sENG and disable Fey receptor interactions, can be developed as therapeutic agents for treating diseases and conditions of pregnant women.

[0034] The carboxy-terminal sequence of short sENG can be determined experimentally following purification from the plasma of preeclamptic women. Purification can be done by affinity purification of patient samples using, for example, immobilised TRC105, followed by direct C- terminal sequencing. Once the sequence is determined it can be expressed as an immunogen for the development of monoclonal antibodies which can be selected for negative binding to membrane endoglin and positive binding to short sENG from the plasma of preeclamptic women.

[0035] In preferred embodiments of the invention, the binding molecule that specifically binds to short sENG is an antibody having an variant Fc domain as herein disclosed.

[0036] The binding molecule of the invention is preferably able to treat or prevent preeclampsia and / or SGA and / or HELLP syndrome. Treatment or prevention is suitably by binding to short sENG and thereby causing the removal of short sENG from the circulation.

[0037] In an embodiment, the present disclosure is directed to recombinant polypeptides comprising a variant Fc domain with amino acid substitutions resulting in a reduction of maternofetal transfer by more than 90%, preferably more than 95% and preferably by more than 96%, more than 97%, or more than 98%.

[0038] In an embodiment, the binding molecule of the disclosure comprises a human variant IgG Fc domain comprising amino acid substitutions numbered according to the Eu numbering scheme, relative to a human parent Fc domain, which optionally is a wildtype domain, wherein: a) (i) positions 234 and 235 are each substituted with alanine or

[0039] (ii) positions 234 and 235 are each substituted with alanine and position 331 is substituted with serine or

[0040] (iii) position 234 is substituted with phenylalanine, position 235 is substituted with glutamic acid and position 331 is substituted with serine or

[0041] (iv) position 328 is substituted with arginine and arginine is inserted after position 236; and b) (i) position 253 is substituted with alanine or

[0042] (ii) position 435 is substituted with alanine or

[0043] (iii) positions 253, 310 and 435 are substituted with alanine or

[0044] (iv) position 310 is substituted with alanine and position 435 is substituted with glutamine In addition to a role in maternofetal transfer of antibodies, the FcRn receptor is important for maintaining the long half-life of IgG in the circulation. Blood proteins are subject to endocytosis by endothelial cells and directed to catabolic degradation. IgG, however, binds to the FcRn receptor in the low pH of the endosomes and is recycled to the endothelium and released in this neutral pH environment. Disabling the binding to FcRn prevents the operation of this rescue mechanism meaning the IgG half-life will be reduced, for example, from five days to two days as demonstrated in the mouse (see US 6,277,375 Bl). The normal half-life for natural sequence antibodies in humans is about 10 to 20 days and is reduced from 2 to 10 fold by inhibition of recycling.

[0045] In the treatment of pregnant women with “mother-only” antibodies the shorter half-life is an advantage. The relatively short duration of pregnancy means a long-term treatment is not necessary and a therapeutic antibody can be given by infusion in the short term if high doses are of benefit. One major modality of therapeutic antibodies is to bind and remove soluble target proteins from the circulation, e.g. short sENG, during pregnancy. A short half-life means that such targets are bound and removed quickly from the maternal circulation and can even be titrated down in concentration with the antibody if, as for sENG, the concentration can be conveniently measured. Treatment using an antibody with a shorter half-life is also a safety advantage since treatment can be interrupted if important safety issues arise and the antibody is quickly eliminated. A further advantage of a shorter half-life for the mother is that the therapeutic antibody does not persist after delivery when the treatment may no longer have utility for the mother or indeed be potentially harmful. Preferably a binding molecule, e.g. a therapeutic antibody, of the invention has a half-life which is reduced by a factor of at least 2 fold, at least 3 fold, at least 5 fold, at least 10 fold or more compared to the same molecule with the 'parent' Fc domain

[0046] Antibodies transferred from the mother to fetus, for example during therapeutic treatment of a preexisting disease of the mother, can persist for many weeks indicating that the FcRn recycling mechanism responsible for the persistence of IgG in the circulation is active also in neonates. Conversely, removal of FcRn binding means that even if “mother-only” antibodies have a low level of placental transfer they will be quickly eliminated in the neonate and any possible risk will be further reduced.

[0047] Disabling of the FcyRs is also a desirable feature for treatments against targets that are soluble proteins but also have membrane equivalents in that immune effector dependent activities, such as antibody-directed cellular cytotoxicity, which could mediate unwanted and off-target side effects will be greatly reduced or abolished.

[0048] The present disclosure also provides an isolated nucleic acid comprising a sequence encoding the polypeptide binding molecule (e.g. antibody) of the disclosure. Also provided are compositions, expression vectors, and host cells which comprise a nucleic acid comprising a sequence encoding the polypeptide of the disclosure. The host cell can comprise an isolated nucleic acid comprising a sequence encoding the polypeptide binding molecule of the disclosure, a composition comprising a nucleic acid comprising a sequence encoding the polypeptide binding molecule of the disclosure, or an expression vector comprising a nucleic acid comprising a sequence encoding the polypeptide binding molecule of the disclosure.

[0049] The present disclosure also provides a method of making a binding molecule of the disclosure comprising (a) culturing host cells comprising a nucleic acid comprising a sequence encoding the polypeptide of the disclosure; and (b) isolating the polypeptide. The present disclosure also provides a composition comprising a binding molecule of the disclosure and a carrier.

[0050] The present disclosure also provides a conjugate comprising a binding molecule of the disclosure and a therapeutic moiety.

[0051] The present disclosure also provides a method of treating a mammal, preferably a human, preferably a woman, more preferably a pregnant woman comprising administering to a patient in need of treatment an effective amount of (a) a binding molecule of the disclosure, (b) an isolated nucleic acid comprising a sequence encoding the polypeptide binding molecule of the disclosure, (c) a composition, expression vector, or host cell which comprises a nucleic acid comprising a sequence encoding the polypeptide binding molecule of the disclosure, (d) a composition comprising a binding molecule of the disclosure and a carrier, or (e) a conjugate comprising a binding molecule of the disclosure and a therapeutic moiety.

[0052] The present disclosure also provides a method to reduce binding to at least one FcyR receptor and to FcRn in a parent polypeptide comprising an Fc domain comprising the steps of: a) (i) positions 234 and 235 are each substituted with alanine or

[0053] (ii) positions 234 and 235 are each substituted with alanine and position 331 is substituted with serine or (iii) position 234 is substituted with phenylalanine, position 235 is substituted with glutamic acid and position 331 is substituted with serine or

[0054] (iv) position 328 is substituted with arginine and arginine is inserted after position 236; and b) (i) position 253 is substituted with alanine or

[0055] (ii) position 435 is substituted with alanine or

[0056] (iii) positions 253, 310 and 435 are substituted with alanine or

[0057] (iv) position 310 is substituted with alanine and position 435 is substituted with glutamine.

[0058] Other preferred features of the disclosure include:

[0059] An isolated binding molecule for use in medicine in a pregnant woman, wherein the binding molecule binds to short sENG and comprises a human variant IgGFc domain having a mutation or combination of mutations with respect to the parent sequence which reduces binding of the Fc domain to any FcyR, and a mutation or combination of mutations with respect to the parent sequence which reduce binding of the Fc domain to FcRn, whereby maternofetal transfer is inhibited with respect to the parent sequence by at least 95% or more.

[0060] An isolated binding molecule for use in the treatment or prevention of a disorder of pregnancy in a pregnant woman, wherein the binding molecule binds to short sENG and comprises a human variant IgGFc domain having a mutation or combination of mutations with respect to the parent sequence which reduce binding of the Fc domain to any FcyR, and a mutation or combination of mutations with respect to the parent sequence which reduce binding of the Fc domain to FcRn, whereby maternofetal transfer is inhibited with respect to the parent sequence by at least 95% or more.

[0061] An isolated binding molecule for use as disclosed herein, or a method of treatment or nucleic acid or cell or vector for use, as disclosed herein, wherein the use is in the treatment or prevention of a disorder of pregnancy, optionally wherein the disorder or disease is a hypertension-related condition or pre-eclampsia / eclampsia and / or SGA and / or HELLP Syndrome (Hemolysis, Elevated Liver enzymes and Low Platelets).

[0062] The present disclosure also provides an isolated binding molecule comprising a binding domain that specifically binds to short soluble endoglin (short sENG), or a fragment thereof, optionally wherein the binding domain binds to an N-terminal or C-terminal fragment of short sENG. Optionally, the binding molecule is an antibody, such as a monoclonal antibody, optionally a human or humanized monoclonal antibody.

[0063] FIGURES

[0064] Figure 1 is a gel electrophoresis of purified antibodies WBP70323 1 (MOm301) and WBP70323_2 (MOm303)

[0065] Figure 2 shows fold changes of total fluorescence signal of pregnant mice and foetuses compared to a PBS control. Panel A; pregnant mice prior to dissection of foetuses. Panel B; foetuses. Figure 2A and Figure 2B each display 3 sets of data which are, reading left to right, G1 PBS, G2 BB301-AF647 and G3 BB303-AF647.

[0066] Figure 3 shows Plasma concentrations of BB301 and BB303 in pregnant mice and foetuses 24 hours after dosing. Plasma levels in the PBS controls were negative and are not shown.

[0067] Figure 4. Gel electrophoresis of purified antibodies WBP71785 1 (MOm601) and WBP71785 2 (MOm623)

[0068] Figure 5. Plasma concentrations ofWBP71785_l (MOm601) and WBP71785 2 (MOm623) in pregnant mice and foetuses 12 hours after dosing.

[0069] DETAILED DESCRIPTION The present disclosure is directed to recombinant polypeptides that are binding molecules that specifically bind to short sENG and optionally comprise a variant Fc domain with amino acid substitutions resulting in reduced maternofetal transfer.

[0070] As used herein, “specifically binds to short sENG” means that the binding molecule binds to truncated forms of the full-length soluble ENG molecule, and does not bind to other molecules that are not sENG. For example, the binding molecule of the present disclosure does not bind to membrane- spanning endoglin, and does not bind to other non-endoglin molecules.

[0071] The molecule referred to herein as “short sENG” is a monomer caused by the removal of carboxyterminal sequences of sENG which, in the extracellular domain, are linked by one or more disulphide bridges. Short sENG may therefore be defined as a group of molecules, of similar molecular weight, that are smaller than the full extracellular domain soluble ENG molecule.

[0072] In an embodiment, a binding molecule that specifically binds to short sENG only binds to the naturally circulating form(s) of sENG, which are shorter than the full length extracellular domain version of sENG. The natural-occurring short sENG molecules can be identified in blood samples from women experiencing preelcampsia and related conditions.

[0073] In an embodiment, a binding molecule that specifically binds to short sENG does not bind to full extracellular domain version of sENG.

[0074] In an embodiment, a binding molecule that specifically binds to short sENG only binds to truncated forms of the full-length soluble endoglin molecule.

[0075] In an embodiment, the present disclosure relates in particular to polypeptides, more particularly immunoglobulins, comprising an IgG Fc domain (e.g., a human IgG Fc domain), or a fragment thereof (preferably an Fc or hinge-Fc domain) that contains one or more amino acid modifications relative to a parent IgG, which is optionally a wild type IgG sequence, and wherein such modifications greatly reduce both FcyR binding and FcRn binding.

[0076] In some aspects, the present disclosure particularly relates to the modification of human or humanized IgGs and other bioactive molecules containing FcRn-binding portions of human IgG Fc domains, which have particular use in therapy, prophylaxis and diagnosis. In some aspects, the polypeptides comprise an IgG Fc domain, or fragment thereof (preferably an Fc or hinge-Fc domain) comprising modifications inhibiting FcyR binding and FcRn binding.

[0077] Definitions

[0078] It is to be noted that the term "a" or "an" entity refers to one or more of that entity; for example, "a polypeptide sequence," is understood to represent one or more polypeptide sequences. As such, the terms "a" (or "an"), "one or more," and "at least one" can be used interchangeably herein. Furthermore, "and / or" where used herein is to be taken as specific disclosure of each of the two specified features or components with or without the other. Thus, the term and / or" as used in a phrase such as "A and / or B" herein is intended to include "A and B," "A or B," "A" (alone), and "B" (alone). Likewise, the term "and / or" as used in a phrase such as "A, B, and / or C" is intended to encompass each of the following aspects: A, B, and C; A, B, or C; A or C; A or B; B or C; A and C; A and B; B and C; A (alone); B (alone); and C (alone).

[0079] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure is related. For example, the Concise Dictionary of Biomedicine and Molecular Biology, Juo, Pei-Show, 2nd ed., 2002, CRC Press; The Dictionary of Cell and Molecular Biology, 3rd ed., 1999, Academic Press; and the Oxford Dictionary Of Biochemistry And Molecular Biology, Revised, 2000, Oxford University Press, provide one of skill with a general dictionary of many of the terms used in this disclosure.

[0080] Units, prefixes, and symbols are denoted in their System International of Units (SI) accepted form. Numeric ranges are inclusive of the numbers defining the range. Unless otherwise indicated, amino acid sequences are written left to right in amino to carboxy orientation. The headings provided herein are not limitations of the various aspects, which can be had by reference to the specification as a whole. Accordingly, the terms defined immediately below are more fully defined by reference to the specification in its entirety.

[0081] It is understood that wherever aspects are described herein with the language "comprising," otherwise analogous aspects described in terms of "consisting of' and / or "consisting essentially of' are also provided. Amino acids can be referred to herein by either their name, their commonly known three letter symbols or by the one-letter symbols recommended by the IUPAC-IUB Biochemical Nomenclature Commission. Nucleotides, likewise, are referred to by their commonly accepted single-letter codes.

[0082] As used herein, the term "polypeptide" refers to a molecule composed of monomers (amino acids) linearly linked by amide bonds (also known as peptide bonds). The term "polypeptide" refers to any chain or chains of two or more amino acids, and does not refer to a specific length of the product. As used herein the term "protein" is intended to encompass a molecule comprised of one or more polypeptides, which can in some instances be associated by bonds other than amide bonds. On the other hand, a protein can also be a single polypeptide chain. In this latter instance the single polypeptide chain can in some instances comprise two or more polypeptide subunits fused together to form a protein. The terms "polypeptide" and "protein" also refer to the products of postexpression modifications, including without limitation glycosylation, acetylation, phosphorylation, amidation, derivatization by known protecting / blocking groups, proteolytic cleavage, or modification by non-naturally occurring amino acids. A polypeptide or protein can be derived from a natural biological source or produced by recombinant technology, but is not necessarily translated from a designated nucleic acid sequence. It can be generated in any manner, including by chemical synthesis.

[0083] A polypeptide, antibody, polynucleotide, vector, cell, or composition which is "isolated" is a polypeptide, antibody, polynucleotide, vector, cell, or composition which is in a form not found in nature. Isolated polypeptides, antibodies, polynucleotides, vectors, cells or compositions include those which have been purified to a degree that they are no longer in a form in which they are found in nature. In some aspects, an antibody, polynucleotide, vector, cell, or composition which is isolated is substantially pure.

[0084] A reference to an isolated polypeptide comprising a human variant IgG Fc domain herein can be a reference to a single polypeptide or, more preferred, refers to a combination of two separate polypeptides that together form an Fc domain e.g. via one or more disulphide bonds, which might also be described as a protein comprising a human variant IgG Fc domain herein.

[0085] A "recombinant" polypeptide or protein refers to a polypeptide or protein produced via recombinant DNA technology. Recombinantly produced polypeptides and proteins expressed in host cells are considered isolated for the purpose of the present disclosure, as are native or recombinant polypeptides which have been separated, fractionated, or partially or substantially purified by any suitable technique.

[0086] Also included in the present disclosure are fragments, variants, or derivatives of polypeptides, and any combination thereof. The term "fragment" when referring to polypeptides and proteins of the present disclosure include any polypeptides or proteins which retain at least some of the properties of the reference polypeptide or protein. Fragments of polypeptides include proteolytic fragments, as well as deletion fragments.

[0087] The term "variant" as used herein refers to a polypeptide sequence that differs from that of its parent polypeptide sequence by virtue of at least one amino acid modification. The parent polypeptide can be a naturally occurring polypeptide including known allotypes, i.e., a "wild-type" ("wt") polypeptide, or can be a modified version of a wild-type polypeptide that does not already contain all of the Fc domain amino acid substitutions disclosed herein, and into which any one of the substitutions disclosed herein can be introduced, resulting in a change in Fc domain sequence.

[0088] Examples of modifications to natural wild type IgG sequences which are incorporated in currently approved antibodies include but are not limited to: IgGl(N297A), IgGl(N297G), IgGl (L234F / L235E / P331 S), IgGl (L234A / L235 A), IgGl (L235V / F243L / R292P / Y300L / P396L), IgGl(L234F / L235E / P331S), IgGl(L234A / L235A / P329G), IgGl(S354C / T366W),

[0089] IgGl(Y349C / T366S / L368A / Y407V), IgGl(M252Y / S254T / T256E), IgGl / 2(S239D / I332E),

[0090] IgG2(C131S / R133K / C219S), IgG2(H268Q / R355Q / Q419E / N434A), IgG2 / 4(M428L / N434S), IgG4(S228P), IgG4(S228P / F234A / L235A), IgG4(S228P / L235E), IgG4(S241P / F234A / L235A), IgG4(F405L / R409K). Thus an IgG sequence which is a natural wild type allotype with any of these modifications, or combination of modifications, is a ‘parent’ polypeptide or Fc domain, as defined herein, and the parent amino acid sequence can be then modified to include the Fc domain amino acid substitutions as disclosed herein. Known human allotype sequences are listed in a number of databases, for example ImMunoGeneTics (http : Z / www. imgt. org) .

[0091] The term variant polypeptide can refer to the polypeptide itself, a composition comprising the polypeptide, or the amino sequence that encodes it. Preferably, the variant polypeptide (e.g., a polypeptide comprising a variant IgG Fc domain) has at least one amino acid modification compared to the parent polypeptide, e.g., from about one to about ten amino acid modifications, and preferably from about one to about six amino acid modifications compared to the parent polypeptide. The variant polypeptide sequence herein will generally possess at least about 90% sequence identity with a parent polypeptide sequence, and most generally at least about 95% sequence identity, for example when considered over the region of the whole antibody chain.

[0092] Variants of polypeptides or proteins of the present disclosure include fragments as described above, and also polypeptides or proteins with altered amino acid sequences due to amino acid substitutions, deletions, or insertions. Variants can be naturally or non-naturally occurring. Non- naturally occurring variants can be produced using mutagenesis techniques known in the art. Variant polypeptides can comprise conservative or non-conservative amino acid substitutions, deletions or additions.

[0093] The term "derivatives" as applied to polypeptides or proteins refers to polypeptides or proteins which have been altered so as to exhibit additional features not found on the native polypeptide or protein. An example of a "derivative" of a variant Fc domain is a fusion or a conjugate with a second polypeptide or another molecule (e.g., a polymer, a chromophore, or a fluor ophore) or a chelating chemical structure capable of binding an atom (e.g., a radioisotope).

[0094] The terms "polynucleotide" or "nucleotide" as used herein are intended to encompass a singular nucleic acid as well as plural nucleic acids, and refers to an isolated nucleic acid molecule or construct, e.g., messenger RNA (mRNA) or plasmid DNA (pDNA). In certain aspects, a polynucleotide comprises a conventional phosphodi ester bond or a nonconventional bond (e.g., an amide bond, such as found in peptide nucleic acids (PNA)).

[0095] The term "nucleic acid" refers to any one or more nucleic acid segments, e.g., DNA or RNA fragments, present in a polynucleotide. When applied to a nucleic acid or polynucleotide, the term "isolated" refers to a nucleic acid molecule, DNA or RNA, which has been removed from its native environment, for example, a recombinant polynucleotide encoding a polypeptide comprising a variant Fc domain contained in a vector is considered isolated for the purposes of the present disclosure. Further examples of an isolated polynucleotide include recombinant polynucleotides maintained in heterologous host cells or purified (partially or substantially) from other polynucleotides in a solution. Isolated RNA molecules include in vivo or in vitro RNA transcripts of polynucleotides of the present disclosure. Isolated polynucleotides or nucleic acids according to the present disclosure further include such molecules produced synthetically. In addition, a

[0096] Y1 polynucleotide or a nucleic acid can include regulatory elements such as promoters, enhancers, ribosome binding sites, or transcription termination signals.

[0097] As used herein, the term "host cell" refers to a cell or a population of cells harboring or capable of harboring a recombinant nucleic acid. Host cells can be a prokaryotic cells (e.g., E. coli), or alternatively, the host cells can be eukaryotic, for example, fungal cells (e.g., yeast cells such as Saccharomyces cerivisiae, Pichia pastoris, or Schizosaccharomyces pombe), and various animal cells, such as insect cells (e.g., Sf-9) or mammalian cells (e.g., HEK293F, CHO, COS- 7, NIH- 3T3, PERC6).

[0098] The present disclosure also encompasses polypeptides comprising a variant IgG Fc domain comprising one or more conservative amino acid substitutions. A "conservative amino acid substitution" is one in which the amino acid residue is replaced with an amino acid residue having a similar side chain. Families of amino acid residues having similar side chains have been defined in the art, including basic side chains (e.g., lysine, arginine, histidine), acidic side chains (e.g., aspartic acid, glutamic acid), uncharged polar side chains (e.g., glycine, asparagine, glutamine, serine, threonine, tyrosine, cysteine), nonpolar side chains (e.g., alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, tryptophan), beta-branched side chains (e.g., threonine, valine, isoleucine) and aromatic side chains (e.g., tyrosine, phenylalanine, tryptophan, histidine). Thus, if an amino acid in a polypeptide is replaced with another amino acid from the same side chain family, the substitution is considered to be conservative. In another aspect, a string of amino acids can be conservatively replaced with a structurally similar string that differs in order and / or composition of side chain family members.

[0099] The term "percent sequence identity" between two polynucleotide or polypeptide sequences refers to the number of identical matched positions shared by the sequences over a comparison window, taking into account additions or deletions (i.e., gaps) that must be introduced for optimal alignment of the two sequences. A matched position is any position where an identical nucleotide or amino acid is presented in both the target and reference sequence. Gaps presented in the target sequence are not counted since gaps are not nucleotides or amino acids. Likewise, gaps presented in the reference sequence are not counted since target sequence nucleotides or amino acids are counted, not nucleotides or amino acids from the reference sequence. The percentage of sequence identity is calculated by determining the number of positions at which the identical amino-acid residue or nucleic acid base occurs in both sequences to yield the number of matched positions, dividing the number of matched positions by the total number of positions in the window of comparison and multiplying the result by 100 to yield the percentage of sequence identity. The comparison of sequences and determination of percent sequence identity between two sequences can be accomplished using readily available software both for online use and for download. Suitable software programs are available from various sources, and for alignment of both protein and nucleotide sequences. One suitable program to determine percent sequence identity is bl2seq, part of the BLAST suite of program available from the U.S. government's National Center for Biotechnology Information BLAST web site (blast.ncbi.nlm.nih.gov). B12seq performs a comparison between two sequences using either the BLASTN or BLASTP algorithm. BLASTN is used to compare nucleic acid sequences, while BLASTP is used to compare amino acid sequences. Other suitable programs are, e.g., Needle, Stretcher, Water, or Matcher, part of the EMBOSS suite of bioinformatics programs and also available from the European Bioinformatics Institute (EBI) at www.ebi.ac.uk / Tools / psa.

[0100] Different regions within a single polynucleotide or polypeptide target sequence that aligns with a polynucleotide or polypeptide reference sequence can each have their own percent sequence identity. It is noted that the percent sequence identity value is rounded to the nearest tenth. For example, 80.11, 80.12, 80.13, and 80.14 are rounded down to 80.1, while 80.15, 80.16, 80.17, 80.18, and 80.19 are rounded up to 80.2. It also is noted that the length value will always be an integer.

[0101] One skilled in the art will appreciate that the generation of a sequence alignment for the calculation of a percent sequence identity is not limited to binary sequence-sequence comparisons exclusively driven by primary sequence data. Sequence alignments can be derived from multiple sequence alignments. One suitable program to generate multiple sequence alignments is ClustalW2, available from www.clustal.org. Another suitable program is MUSCLE, available from www.drive5.com / muscle / . ClustalW2 and MUSCLE are alternatively available, e.g., from the EBI.

[0102] It will also be appreciated that sequence alignments can be generated by integrating sequence data with data from heterogeneous sources such as structural data (e.g., crystallographic protein structures), functional data (e.g., location of mutations), or phylogenetic data. A suitable program that integrates heterogeneous data to generate a multiple sequence alignment is T-Coffee, available at www.tcoffee.org, and alternatively available, e.g., from the EBI. It will also be appreciated that the final alignment used to calculate percent sequence identity can be curated either automatically or manually.

[0103] The term "antibody" means an immunoglobulin molecule that recognizes and specifically binds to a target, such as a protein, polypeptide, peptide, carbohydrate, polynucleotide, lipid, or combinations of the foregoing through at least one antigen recognition site within the variable region of the immunoglobulin molecule. As used herein, the term "antibody" encompasses intact polyclonal antibodies, intact monoclonal antibodies, antibody fragments (such as Fab, Fab', F(ab')2, and Fv fragments), single chain Fv (scFv) mutants, multispecific antibodies such as bispecific antibodies generated from at least two intact antibodies, chimeric antibodies, humanized antibodies, human antibodies, fusion proteins comprising an antigen determination portion of an antibody, and any other modified immunoglobulin molecule comprising an antigen recognition site so long as the antibodies exhibit the desired biological activity. An antibody can be of any the five major classes of immunoglobulins: IgA, IgD, IgE, IgG, and IgM, or subclasses (isotypes) thereof, based on the identity of their heavy-chain constant domains referred to as alpha, delta, epsilon, gamma, and mu, respectively. The different classes of immunoglobulins have different and well known subunit structures and three-dimensional configurations. Antibodies can be naked or conjugated to other molecules such as toxins, radioisotopes, etc. The terms "antibody" or "immunoglobulin," as used interchangeably herein, include whole antibodies and any antigen binding fragment or single chains thereof.

[0104] The term "IgG" as used herein refers to a polypeptide belonging to the class of antibodies that are substantially encoded by a recognized immunoglobulin gamma gene. In humans this class comprises IgGl, IgG2, IgG3, and IgG4. In mice this class comprises IgGl, IgG2a, IgG2b, and IgG3.

[0105] The term "antigen binding fragment" refers to a portion of an intact antibody and refers to the antigenic determining variable regions of an intact antibody. It is known in the art that the antigen binding function of an antibody can be performed by fragments of a full-length antibody. Examples of antibody fragments include, but are not limited to Fab, Fab', F(ab')2, and Fv fragments, linear antibodies, single chain antibodies, and multispecific antibodies formed from antibody fragments. The term "monoclonal antibody" refers to a homogeneous antibody population involved in the highly specific recognition and binding of a single antigenic determinant, or epitope. This is in contrast to polyclonal antibodies that typically include different antibodies directed against different antigenic determinants. The term "monoclonal antibody" encompasses both intact and full-length monoclonal antibodies as well as antibody fragments (such as Fab, Fab', F(ab')2, Fv), single chain (scFv) mutants, fusion proteins comprising an antibody portion, and any other modified immunoglobulin molecule comprising an antigen recognition site. Furthermore, "monoclonal antibody" refers to such antibodies made in any number of ways including, but not limited to, by hybridoma, phage selection, recombinant expression, and transgenic animals.

[0106] The term "human antibody" refers to an antibody produced by a human or an antibody having an amino acid sequence corresponding to an antibody produced by a human made using any technique known in the art. This definition of a human antibody includes intact or full-length antibodies, fragments thereof, and / or antibodies comprising at least one human heavy and / or light chain polypeptide such as, for example, an antibody comprising murine light chain and human heavy chain polypeptides. The term "humanized antibody" refers to an antibody derived from a nonhuman (e.g., murine) immunoglobulin, which has been engineered to contain minimal non- human (e.g., murine) sequences.

[0107] The term "chimeric antibodies" refers to antibodies wherein the amino acid sequence of the immunoglobulin molecule is derived from two or more species. Typically, the variable region of both light and heavy chains corresponds to the variable region of antibodies derived from one species of mammals (e.g., mouse, rat, rabbit, etc) with the desired specificity, affinity, and capability while the constant regions are homologous to the sequences in antibodies derived from another (usually human) to avoid eliciting an immune response in that species.

[0108] IgG immunoglobulins naturally comprise a pair of ‘heavy chain’ polypeptides, containing around 450 amino acids in IgGl, and a pair of Tight chains’, containing around 110 amino acids in IgGl, which are bound in amino-terminal to amino-terminal orientation with each heavy chain, a structure represented by a cartoon ‘Y’ shape. The arms of the Y carry the ‘complementaritydetermining regions’, which are binding sites for molecular targets of the antibody formed between the ’so-called’ variable regions of each pair of heavy and light chains. These ‘variable’ regions of the protein can have many thousands of different sequences depending on the structure of the binding sites and the nature of the target and normally determine the binding properties of the antibody. The carboxy-terminal regions of the two heavy chains are linked to form the trunk of the Y. Treatment of a whole antibody with the enzyme ‘papain’ cleaves at the junction of the Y and releases the two arms, known as Fab fragments and carrying the target binding regions, and a single trunk fragment which, due to being readily crystallisable, is known as the Fc (fragment crystallisable) region. The amino-terminal regions of the light and heavy chains thus contain variable regions which determine ‘complementarity regions’ designated VL and VH respectively. A light chain also comprises a so-called ‘constant’ region, CL, and heavy chains comprise three ‘constant’ regions known as CHI, CH2 and CH3 in the human IgG nomenclature. In this context ‘constant’ is to distinguish from the highly variable complementarity-determining regions (CDR) sequences and these ‘constant’ sequences are subject to natural variations, allotypes, due to population genetic polymorphisms. In the intact antibody the constant region of the light chain, CL, and the first constant region of the heavy chain for the lower part of the arms of the ‘Y’ and the ‘hinge region’ of an antibody is normally between CHI and CH2.

[0109] The treatment of an intact antibody with the enzyme papain cleaves both heavy chains between CHI and CH2 constant domains so that the resulting Fc fragment comprises a dimer of two heavy chains with some of the hinge region sequence and the full constant domains CH2 and CH3. Sequences for Human Fc variants are presented herein as the entire heavy chain constant region including CHI, the hinge region and regions CH2 and CH3 and normally start with the sequence alanine-serine-threonine-lysine-glycine. However it will be clear to a skilled person that ‘Fc domain’ normally refers to a dimer comprising the CH2 and CH3 regions from two individual heavy chains and that the full sequence of the constant heavy chain region is provided for clarity and consistency across antibody types: IgG 1 to IgG4 for example.

[0110] The assignment of amino acids for antibody sequences uses the following numbering systems: Kabat numbering is used for the variable domains (Kabat, E.A., et al, Sequences of Proteins of Immunological Interest, 5th ed., Public Health Service, National Institutes of Health, Bethesda, MD (1991)) and the Eu numbering scheme is used for constant domains (Edelman, G.M., et al., Proc. Natl. Acad. Sci. USA 63 (1969) 78-85). For example, both "L234" refers to the amino acid leucine at position 234 according to the Eu numberingscheme. The terms "Fc domain" and "IgG Fc domain" as used herein refer to the Fc region of an immunoglobulin, e.g., an IgG molecule, which comprises the C-terminal half of two heavy chains of an IgG molecule that are linked by disulfide bonds. It has no antigen binding activity but contains the carbohydrate moiety and binding sites for complement and Fc receptors, including the FcRn receptor. For example, the Fc region contains a part of the hinge region plus the entire second constant domain CH2 (residues 231-340 of human IgGl, according to the Eu numbering scheme and the third constant domain CH3 (residues 341-447). Fc can refer to this region in isolation, or this region in the context of an antibody, antibody fragment, or Fc fusion protein.

[0111] Despite being designated ‘constant’ regions in the natural sequences of antibodies the CH 1-3 regions have small differences in sequence between individuals and between populations. Such differences, known as allotypes and polymorphisms, often occur as single amino-acid changes and have been observed at a number of positions in Fc domains both between classes, meaning IgG 1,2,3 and 4, and within classes. For example natural allotypes (variants) of IgGl include Glm3, Glml7,l or Glml7,l,2 allotypes or Glm(f), Glm(z,a), Glm(z,a,x) which differ by one to ten or more amino acid changes in the heavy chain constant region. (DeTaeye, S.W., et al, FcyR Binding and ADCC Activity ofHuman IgG Allotypes, Frontiers in Immunology 2020, 11: 1-16). A number of databases provide examples of known polymorphisms such as the international ImMunoGeneTics information system (http : Z / www. imgt. or g) . Thus, a "wild type IgGFc domain" or "wt IgG Fc domain" refers to any naturally occurring IgG Fc region and all polymorphisms, allotypes and alleles.

[0112] Sequences of the constant regions of the heavy chains of human IgGl, IgG2, IgG3 and IgG4 can be found in a number of sequence databases, for example, at the Uniprot database (www.uniprot.org) under accession numbers P01857 (IGHG1 HUMAN), P01859 (IGHG2 HUMAN), P01860 (IGHG3 HUMAN), and P01861 (IGHG4 HUMAN), respectively. The sequences for the constant regions of heavy chains for these specific alleles of IgGl -4 are presented, starting at position 119 according to the Eu numbering: IgGl (SEQ ID NO: 1), IgG2 (SEQ ID NO:2), IgG3 (SEQ ID NO:3) and IgG4 (SEQ ID NO:4).

[0113] IgG light chains can take the form of either so-called Kappa sequences or Lamba sequences. Light chains presented in the application include either form, and include polymorphisms in the constant light chain region. The terms "variant IgG Fc domain" and "IgG Fc variant domain" as used herein refers to an IgG Fc domain comprising one or more amino acid substitutions, deletions, insertions or modifications introduced at any position within the Fc domain. In certain aspects a variant IgG Fc domain comprises one or more amino acid substitutions resulting in decreased or ablated binding affinity for an FcyR and FcRn as compared to the parent Fc domain (which may be a wild type domain) not comprising the one or more amino acid substitutions.

[0114] The term "Fc fusion" as used herein refers to a protein in which one or more polypeptides or small molecules are operably linked to an Fc domain or a variant or derivative thereof. An Fc fusion combines the Fc region of an immunoglobulin with a fusion partner, which in general can be any protein or small molecule. The role of the non-Fc part of an Fc fusion, i.e., the fusion partner, can be to mediate target binding, and thus it can be functionally analogous to the variable regions of an antibody.

[0115] The term "parent" polypeptide as used herein refers to a polypeptide (e.g., a parent Fc domain, or a polypeptide comprising an Fc domain such as antibody or Fc fusion) that is subsequently modified to generate a variant (e.g., a variant Fc domain, or a variant polypeptide comprising an Fc domain such as a variant antibody or a variant Fc fusion). The parent polypeptide can be a naturally occurring polypeptide (e.g., a wild type Fc domain), or a variant or engineered version of a naturally occurring polypeptide. The term parent polypeptide can refer to the polypeptide itself, compositions that comprise the parent polypeptide, or the amino acid sequence that encodes it. Accordingly, by "parent Fc domain" as used herein is meant a Fc domain that is modified to generate a variant, and by "parent antibody" as used herein is meant an antibody that is modified to generate a variant antibody comprising an IgG variant Fc domain.

[0116] A parent polypeptide sequence may be the constant heavy chain sequence of TRC105 (SEQ ID NO: 11), or the equivalent constant heavy chain sequence of the humanised / deimmunised version thereof (SEQ ID NO: 15) or the equivalent constant heavy chain sequence of the humanised version (SEQ ID NO: 19) and therefore examples of suitably modified sequences of these parent polypeptide sequences are SEQ ID NO: 12, 17 and 21 respectively. SEQ ID NO: 5 may be the Fc portion of the heavy chain parent sequence.

[0117] An "Fc variant" comprises an Fc domain and can exist alone or in the context of an antibody, Fc fusion, isolated Fc, Fc fragment, or other polypeptide. Fc variants can refer to the Fc polypeptide itself, compositions comprising the Fc variant polypeptide, or the amino acid sequence that encodes it. The variant IgG Fc domains described herein are defined according to the amino acid modifications that compose them. For all amino acid positions discussed herein, numbering is always according to the Eu numbering scheme. Thus, for example, L234A is an Fc variant with the leucine (L) at EU position 234 substituted with alanine (A) relative to the parent Fc domain. Likewise, e.g., L234A / L235A / L328R defines a variant Fc variant with substitutions at EU positions 234 (L to A), 235 (L to A), and 328 (L to R) relative to the parent Fc domain.

[0118] The terms "Fc gamma receptor" or "FcyR" as used herein refer to any member of the family of proteins that bind the IgG antibody Fc region and are encoded by the FcyR genes. In humans this family includes but is not limited to FcyRI (CD64), including isoforms FcyRIa, FcyRIb, and FcyRIc; FcyRIIa (CD32), including isoforms FcyRIIa (including allotypes Hl 31 and R131), FcyRIIb (including FcyRIIb- 1 and FcyRIIb-2), and FcyRIIc; and FcyRIII (CD 16), including isoforms FcyRIIIa (including allotypes VI 58 and Fl 58) and FcyRIIIb (including allotypes FcyRIIIb-NAl and FcyRIIIb-NA2), as well as any undiscovered human FcyRs or FcyR isoforms or allotypes. An FcyR can be from any organism, including but not limited to humans, mice, rats, rabbits, and monkeys. Mouse FcyRs include but are not limited to FcyRI (CD64), FcyRIIb (CD32), FcyRIII (CD 16), and FcyRIV (CD 16-2), as well as any undiscovered mouse FcyRs or FcyR isoforms or allotypes.

[0119] The term "FcRn" or "FcRn receptor" as used herein refers to an Fc receptor ("n" indicates neonatal based on the first identified function) which is known to be involved in transfer of maternal IgGs to a fetus through the human or primate placenta, or yolk sac (rabbits, rats and mice) and to a neonate from the colostrum through the small intestine. It is also known that FcRn is involved in the maintenance of constant serum IgG levels by binding the IgG molecules and recycling them into the serum. The binding of FcRn to IgG molecules is pH-dependent with optimum binding at pH 6.0 and weak binding at pH >7.0. Whereas the binding of IgGs to FcyR receptors can trigger effector function (e.g., ADCC), binding to FcRn in a pH dependent manner can prolong the halflife on IgG antibodies in the serum. Effector function can be undesirable for a molecule with a prolonged half-life in serum or that target a soluble version of a protein or receptor also displayed by cells. The term "effector function" as used herein refers to a biochemical event that results from the interaction of an Fc domain with an Fc receptor or ligand. Effector functions include but are not limited to ADCC, ADCP, and CDC. By "effector cell" as used herein is meant a cell of the immune system that expresses or one or more Fc receptors and mediates one or more effector functions. Effector cells include but are not limited to monocytes, macrophages, neutrophils, dendritic cells, eosinophils, mast cells, platelets, B cells, large granular lymphocytes, Langerhans' cells, natural killer (NK) cells, and y8 T cells, and can be from any organism included but not limited to humans, mice, rats, rabbits, and monkeys.

[0120] The terms "antibody-dependent cell-mediated cytotoxicity" or "ADCC" refer to a form of cytotoxicity in which a polypeptide comprising an Fc domain, e.g., an antibody, bound onto Fc receptors (FcRs) present on certain cytotoxic cells (e.g., primarily NK cells, neutrophils, and macrophages) and enables these cytotoxic effector cells to bind specifically to an antigen-bearing "target cell" and subsequently kill the target cell with cytotoxins. (Hogarth et al., Nature review Drug Discovery 2012, 11: 313) It is contemplated that, in addition to antibodies and fragments thereof, other polypeptides comprising Fc domains, e.g., Fc fusion proteins and Fc conjugate proteins, having the capacity to bind specifically to an antigen-bearing target cell will be able to effect cell-mediated cytotoxicity.

[0121] For simplicity, the cell-mediated cytotoxicity resulting from the activity of a polypeptide comprising an Fc domain is also referred to herein as ADCC activity. The ability of any particular polypeptide of the present disclosure to mediate lysis of the target cell by ADCC can be assayed. To assess ADCC activity, a polypeptide of interest (e.g., an antibody) is added to target cells in combination with immune effector cells, resulting in cytolysis of the target cell. Cytolysis is generally detected by the release of label (e.g., radioactive substrates, fluorescent dyes or natural intracellular proteins) from the lysed cells. Useful effector cells for such assays include peripheral blood mononuclear cells (PBMC) and Natural Killer (NK) cells.

[0122] The term “ADCP” as used herein refers to antibody directed cellular phagocytosis, i.e., provides mechanisms for clearance of virus and virus-infected cells, as well as for stimulation of downstream adaptive immune responses by facilitating antigen presentation, or by stimulating the secretion of inflammatory mediators. The term "CDC" as used herein refers to complement dependent cytotoxicity, i.e., a biochemical event of targeted cell destruction mediated by the complement system.

[0123] The terms "half-life" or "in vivo half-life" as used herein refer to the biological half-life of a particular type of polypeptide of the present disclosure in the circulation of a given animal and is represented by a time required for half the quantity administered in the animal to be cleared from the circulation and / or other tissues in the animal.

[0124] The term "subject" as used herein refers to any animal (e.g., a mammal), including, but not limited to humans, non-human primates, rodents, and the like, which is to be the recipient of a particular treatment. The terms "subject" and "patient" are used interchangeably herein in reference to a human subject.

[0125] The term "pharmaceutical composition" as used herein refers to a preparation which is in such form as to permit the biological activity of the active ingredient to be effective, and which contains no additional components which are unacceptably toxic to a subject to which the composition would be administered. Such composition can be sterile.

[0126] An "effective amount" of a polypeptide, e.g., an antibody, as disclosed herein is an amount sufficient to carry out a specifically stated purpose. An "effective amount" can be determined empirically and in a routine manner, in relation to the stated purpose. The term "therapeutically effective amount" as used herein refers to an amount of a polypeptide, e.g., an antibody, or other drug effective to "treat" a disease or disorder in a subject or mammal.

[0127] The term "label" when used herein refers to a detectable compound or composition which is conjugated directly or indirectly to a polypeptide, e.g., an antibody, so as to generate a "labeled" polypeptide. The label can be detectable by itself (e.g., radioisotope labels or fluorescent labels) or, in the case of an enzymatic label, can catalyze chemical alteration of a substrate compound or composition which is detectable.

[0128] Terms such as "treating" or "treatment" or "to treat" or "alleviating" or "to alleviate" refer to both (1) therapeutic measures that cure, slow down, lessen symptoms of, and / or halt progression of a diagnosed pathologic condition or disorder and (2) prophylactic or preventative measures that prevent and / or slow the development of a targeted pathologic condition or disorder. Thus, those in need of treatment include those already with the disorder; those prone to have the disorder; and those in whom the disorder is to be prevented.

[0129] The treatment or prevention of a disorder of pregnancy in a pregnant woman as described herein refers to treatment of prevention of a disorder in a pregnant woman, and is not intended to cover treatment of pregnancy per se.

[0130] The term "vector" means a construct, which is capable of delivering, and in some aspects, expressing, one or more gene(s) or sequence(s) of interest in a host cell. Examples of vectors include, but are not limited to, viral vectors, naked DNA or RNA expression vectors, plasmid, cosmid or phage vectors, DNA or RNA expression vectors associated with cationic condensing agents, DNA or RNA expression vectors encapsulated in liposomes, and certain eukaryotic cells, such as producer cells.

[0131] Variant IgG Fc Domains

[0132] In some embodiments, variant IgG Fc domains are provided which have mutations that confer reduced maternofetal transfer, preferably by more than 90%, more preferably by more than 95% and more preferably by more than 98% when compared to the same polypeptide comprising a parent Fc domain (which may be a wild type domain). These variant IgG Fc domains can be introduced to therapeutic antibodies to ensure safety of the fetus while treating pregnant women.

[0133] Although FcRn plays a major role in IgG transfer, the inventors made the hypothesis that other receptors were likely involved since FcRn is not present on the fetal endothelium - which would be expected for a FcRn-only transport process - and maternofetal IgG selective transfer depending on glycosylation or antigen specificity has been reported - which does not reflect selectivity of FcRn binding (Jennewein, M.F., et al, Fc Glycan-Mediated Regulation of Placental Antibody Transfer. Cell. 2019, 27: 202-215).

[0134] The FcyRIIb which like FcRn can bind monomeric IgG, is the sole Fc receptor localised to the fetal placental endothelium and, in the absence of FcRn, is reported to be responsible for IgG transfer to the fetal circulation (Ishikawa, T., et al, FcyRIIb participates in maternal IgG trafficking of human placental endothelial cells. Int. J. Mol. Med. 2015, 35: 1273-89). TheFcyRIIIa is detected in the maternal syncytiotrophoblast membrane and is implicated in the selective transfer of digalactosylated IgG, and possibly IgG-3, which poorly binds FcRn, across the placenta (Jennewein, M.F., et al, Fc Glycan-Mediated Regulation of Placental Antibody Transfer. Cell. 2019, 178: 202-215).

[0135] The mutations 1253 A, H310A or H435A disrupt the binding of FcRn to the Fc region and have been shown individually to inhibit maternofetal transfer by no more than 90%. The triple mutation I253A, H310A and H435A in an erythropoietin-Fc fusion protein inhibited transfer across the neonatal mouse intestine and across the lung by up to 50%. This is the first report of the use of all three mutations in the same Fc construct (Spiekermann, G.M., et al, J Exp Med. 2002, 196:303- 10). The triple mutation 1253 A, H310A and H435A has not been tested for the inhibition of the maternofetal transfer of a modified IgG antibody in the prior art.

[0136] FcyR binding sites are located in the CH2 domain of the Fc region and binding can be blocked or greatly reduced by known mutation combinations.

[0137] Introduction of the mutations L234A and L235A into the Fc region of IgG are known to greatly reduce binding by the FcyR receptors tested (Hezareh, M., et al, J Virol. 2001,75: 12161-8.).

[0138] Other modifications known to greatly reduce FcyR binding include the insertion of arginine after G236 with the additional change of L328 to arginine (Chu, S.Y., et al, Molecular Immunology 2008, 45: 3926-33. ) or the changes L234F / L235E / P331S (Oganesyan, V., et al Acta Crystallogr D Biol Crystallogr. 2008, 64: 700-4).

[0139] Accordingly, in some aspects a binding molecule is provided which comprises a human variant IgG Fc domain comprising amino acid substitutions numbered according to the Eu numbering scheme, relative to a human wild- type Fc domain, wherein: a) (i) positions 234 and 235 are each substituted with alanine or

[0140] (ii) positions 234 and 235 are each substituted with alanine and position 331 is substituted with serine or

[0141] (iii) position 234 is substituted with phenylalanine, position 235 is substituted with glutamic acid and position 331 is substituted with serine or

[0142] (iv) position 328 is substituted with arginine and arginine is inserted after position 236; and b) (i) position 253 is substituted with alanine or

[0143] (ii) position 435 is substituted with alanine or

[0144] (iii) positions 253, 310 and 435 are substituted with alanine or

[0145] (iv) position 310 is substituted with alanine and position 435 is substituted with glutamine

[0146] In some aspects a binding molecule is provided which comprises a Human variant IgG-1 Fc domain comprising an amino acid sequence that is at least 80%, preferably at least 90% identical to the amino acid sequence of SEQ ID NO: 5 and is comprising amino acid substitutions numbered according to the Eu numbering scheme, wherein: a) (i) positions 234 and 235 are each substituted with alanine or

[0147] (ii) positions 234 and 235 are each substituted with alanine and position 331 is substituted with serine or

[0148] (iii) position 234 is substituted with phenylalanine, position 235 is substituted with glutamic acid and position 331 is substituted with serine or

[0149] (iv) position 328 is substituted with arginine and arginine is inserted after position 236; and b) (i) position 253 is substituted with alanine or

[0150] (ii) position 435 is substituted with alanine or

[0151] (iii) positions 253, 310 and 435 are substituted with alanine or

[0152] (iv) position 310 is substituted with alanine and position 435 is substituted with glutamine

[0153] The resulting variant Ig Fc domains polypeptide has reduced binding to at least one Fey receptor (FcyR) and to FcRn when compared to the same polypeptide comprising a parent Fc domain (which may be a wildtype domain). The Ig Fc domain can have the same modifications in both polypeptides, modification only in one of the two polypeptides which comprise the Fc domain or different substitutions in each chain. Identical modifications in both polypeptides of the Fc domain is preferred.

[0154] In one embodiment, the resulting variant Ig Fc domains polypeptide exhibits an increase of at least 2 fold, at least 5 fold or at least 10 fold in the concentration of antibody needed to give 50% binding, or activation, in a binding or cellular activation assay and / or a decrease in the Km binding constant by a factor of at least 2 fold, at least 5 fold or at least 10 fold by SPR or equivalent method to at least one Fey receptor and to FcRn when compared to the same polypeptide comprising a parent Fc domain (which may be a wild type domain).

[0155] In one embodiment, at least one FcyR is selected from FcyRI, FcyRIIa, FcyRIIb, FcyRIIIa and FcyRIIIb, preferably FcyRIIb or FcyRIIIa.

[0156] As such, the resulting polypeptide preferably shows reduced maternofetal transfer when compared to the same polypeptide comprising the parent Fc domain (which may be a wild type domain), preferably by more than 90%, more preferably by more than 95%, more preferably by more than 98% when compared to the same polypeptide comprising the parent Fc domain (which may be a wild type domain) but also display a shorter half-life which is also a safety advantage since treatment can be interrupted if important safety issues arise and the antibody is quickly eliminated. The shorter half-life is also a safety advantage in the unlikely event that a low amount of antibody is transferred to the fetus due to placental damage. In such a case the lack of antibody recycling will result in rapid clearance from the fetal circulation.

[0157] In one aspect the polypeptides, antibodies, and compositions of the invention can be dosed at therapeutically effective doses more frequently than polypeptides and antibodies which lack the mutations as disclosed herein, for example can be dosed once a day, once every 2, 3, 4, 5, 6 days or every week.

[0158] In one aspect, a polypeptide is provided which comprises a human variant IgGFc domain, which comprises an alanine (A) at positions 234 and 235 in order to greatly reduce FcyR binding and comprises alanine (A) at positions 253, 310 and 435 in order to greatly reduce FcRn binding. Hereinafter, this variant IgG Fc domain and set of amino acid substitutions will be referred to as "L234A / L235A+I253A / H310A / H435A". In another aspect, a polypeptide is provided which comprises a human variant IgG Fc domain, which comprises alanine (A) at positions 234 and 235 and serine (S) at position 331 and comprises alanine (A) at positions 253, 310 and 435. Hereinafter, this variant IgGFc domain and set of amino acid substitutions will be referred to as "L234A / L235A / P331S+I253A / H310A / H435A”.

[0159] In another aspect, a polypeptide is provided which comprises a human variant IgG Fc domain, which comprises phenylalanine (F) at position 234, glutamic acid (E) at 235 and serine (S) at position 331 and comprises alanine (A) at positions 253, 310 and 435. Hereinafter, this variant IgG Fc domain and set of amino acid substitutions will be referred to as "L234F / L235E / P331 S+I253 A / H310A / H435 A”.

[0160] In another aspect, a polypeptide is provided which comprises a human variant IgG Fc domain, which comprises an arginine (R) inserted after position 236 and an arginine (R) at position 328 and comprises alanine (A) at positions 253, 310 and 435. Hereinafter, this variant IgGFc domain and set of amino acid substitutions will be referred to as "A236R / L328R+I253A / H310A / H435A".

[0161] In another aspect, a polypeptide is provided which comprises a human variant IgG Fc domain, with any of one the FcyR binding reduction mutation sets L234A / L235A, L234A / L235A / P331S, L234F / L235E / P331S orA236R / L328R which comprises alanine (A) at position 253. Hereinafter, this variant IgG Fc domain and set of amino acid substitutions will be referred to as a combination of the FcyR mutation set and “I253A”, for example “L234A / L235A / P331S+I253A”.

[0162] In another aspect, a polypeptide is provided which comprises a human variant IgG Fc domain, with any of one the FcyR binding reduction mutation sets L234A / L235A, L234A / L235A / P331S, L234F / L235E / P331S orA236R / L328R which comprises alanine (A) at position 435. Hereinafter, this variant IgG Fc domain and set of amino acid substitutions will be referred to as a combination of the FcyR mutation set and "H435A”, for example “L234A / L235A / P331S+H435A”.

[0163] In another aspect, a polypeptide is provided which comprises a human variant IgG Fc domain, with any of one the FcyR binding reduction mutation sets L234A / L235A, L234A / L235A / P331S, L234F / L235E / P331 S orA236R / L328R which comprises alanine (A) at position 310 and glutamine (Q) at position 435. Hereinafter, this variant IgG Fc domain and amino acid substitution will be referred to as a combination of the FcyR mutation set and "H310A / H435Q”, for example “L234A / L235A / P331S+ H310A / H435Q”. Thus, a set of polypeptides are provided which comprise a human variant IgG Fc domain with any combination of one of the four amino acid substitution sets L234A / L235A or L234A / L235A / P331S or L234F / L235E / P331S orA236R / L328R with any one of the four ammo acid substitutions or substitution sets I253A / H310A / H435A or 1253 A or H435A or H310A / H435Q. In some aspects, the parent polypeptide of the variant IgG Fc domain already contains one or more of the amino acids corresponding to the substitutions discussed above, e.g., the parent Fc polypeptide can contain a phenylalanine (F) at position 234 as is found in IgG4. In such aspects, no modification of the amino acid or amino acids already containing one or more of the disclosed substitutions is required.

[0164] In some aspects, the variant IgG Fc domain is human. In some other aspects, the variant IgG Fc domain is non-human. Non-human IgG Fc domains can be, e.g., from rodents (e.g., rats or mice), donkey, sheep, rabbit, goat, guinea pig, camel, horse, or chicken. Preferably, the IgGFc domain is selected from the group consisting of human immunoglobulin G class 1 (IgGl) Fc domain, human immunoglobulin G class 2 (IgG2) Fc domain, human immunoglobulin G class 3 (IgG3) Fc domain, and human immunoglobulin G class 4 (IgG4) Fc domain, preferably human immunoglobulin G class 1 (IgGl ) Fc domain. When the variant IgG Fc domain is a mouse IgG Fc domain, the domain can be, e.g., a subclass IgGl, IgG2a, IgG2b, or IgG3 domain.

[0165] In some aspects, a polypeptide is provided which comprises a variant IgG Fc domain comprising an amino acid sequence selected from the group consisting of SEQ ID NO: 5 to SEQ ID NO:9. SEQ ID NO: 5 is a naturally occurring ‘wild type’ sequence corresponding to the Human IgGl allotype Glm3. SEQ ID NO:6 to SEQ ID NO:9 comprise variants of SEQ ID NO:5 which include mutations or mutation sets which greatly reduce FcyRs and / or FcRn binding as follows: SEQ ID NO:6: L234A / L235A / P331S and I253A / H310A / H435A, SEQ ID NO:7: L234A / L235A / P331S and H310A / H435Q, SEQ ID NO:8: L234F / L235E / P331S and I253A / H310A / H435A and SEQ ID NO:9: L234F / L235E / P331S and H310A / H435Q.

[0166] In some aspects, a polypeptide is provided which comprises a variant IgG Fc domain comprising an amino acid sequence that is at least 80%, preferably at least 90%, more preferably at least 95% identical to the amino acid sequence selected from the group consisting of SEQ ID NO: 5 to SEQ ID NO: 9, suitably when considered over the length of SEQ ID NO: 5 to SEQ ID NO: 9, respectively In some other aspects, a polypeptide is provided which comprises a variant IgG Fc domain consisting of an amino acid sequence selected from the group consisting of SEQ ID NO: 5 to SEQ ID NO: 9. Based on the teaching provided herein, it will be understood by one of skill in the art that the variant IgG Fc domains provided in SEQ ID NO: 5 to SEQ ID NO: 9 represent one particular allelic variation. Accordingly, in some aspects, a polypeptide is provided which comprises a different allelic variation of a variant IgG Fc domain as provided in SEQ ID NO: 5 to SEQ ID NO: 9. Sites of known allelic variation are available in the literature and various databases, for example: (Jefferies, R., et al, Human immunoglobulin allotypes: Possible implications for immunogenicity, mAbs 2009, 1: 332-338 and IMGT database: http: / / www.imgt.org).

[0167] Where reference is made to a % identity herein, a mutation or mutations that reduce binding of the Fc domain to any FcyR, and which reduce binding of the Fc domain to FcRn, are retained in the final polypeptide, eg antibody sequence.

[0168] Binding to Fc Receptors

[0169] A polypeptide comprising a variant IgG Fc domain provided herein (e.g., an antibody or fragments thereof comprising a variant IgGFc domain) results in reduced or ablated binding for at least one FcyR receptor (e.g., FcyR lib, FcyR Illa) and the FcRn receptor.

[0170] One skilled in the art will understand that a polypeptide comprising a variant IgG Fc domain can have altered (relative to an unmodified molecule) FcyR and FcRn binding properties. Examples of binding properties include but are not limited to, binding specificity, dissociation and association rates (koff and kon, respectively), equilibrium dissociation constant (KD, defined as the ratio of koff divided by kon), binding affinity and / or avidity.

[0171] The affinities and binding properties of a polypeptide comprising a variant IgGFc domain for a receptor or ligand, can be determined by a variety of in vitro assay methods (biochemical or immunological based assays) known in the art for determining Fc-FcyR and Fc-FcRn interactions, i.e., specific binding of an Fc region to an FcyR. Such methods include equilibrium methods (e.g., enzyme-linked immunoabsorbent assay (ELISA) or radioimmunoassay (RIA)), or kinetics (e.g., surface plasma resonance, such as BIACORE® analysis), and other methods such as indirect binding assays, competitive inhibition assays, fluorescence resonance energy transfer (FRET), gel electrophoresis and chromatography (e.g., gel filtration).

[0172] These and other methods can utilize a label on one or more of the components being examined and / or employ a variety of detection methods including but not limited to chromogenic, fluorescent, luminescent, or isotopic labels. A detailed description of binding affinities and kinetics can be found in Paul, W. E., ed., Fundamental Immunology, 4th Ed., Lippincott-Raven, Philadelphia (1999).

[0173] In one aspect, a polypeptide comprising a variant IgG Fc domain is provided which exhibits reduced binding affinity for at least one Fey receptors including, but not limited to FcyRI (including isoforms FcyRIa, FcyRIb, and FcyRIc); FcyRII (including isoforms FcyRIIa, FcyRIIb, and FcyRIIc); and FcyRIII (including isoforms FcyRIIIa and FcyRIIIb) and for the FcRn receptor as compared to a parent polypeptide comprising a wild type or modified wt Fc domain. In another aspect, the binding of a polypeptide comprising a variant IgG Fc domain to one or more Fey receptors and FcRn as noted above is at least 2 fold, or at least 3 fold, or at least 5 fold, or at least 7 fold, or a least 10 fold, or at least 20 fold, or at least 30 fold, or at least 40 fold, or at least 50 fold, or at least 60 fold, or at least 70 fold, or at least 80 fold, or at least 90 fold, or at least 100 fold, or at least 200 fold less than a parent polypeptide comprising a wild type or modified wt Fc domain or is reduced to an undetectable level.

[0174] In another aspect, the binding of a polypeptide comprising a variant IgG Fc domain to one or more Fey receptors and FcRn as noted above is fully ablated.

[0175] In one aspect, a polypeptide comprising a variant IgG Fc domain is provided which exhibits a decreased affinity to FcyRI relative to a parent polypeptide comprising a wild type or modified wt Fc domain. In another aspect, a polypeptide comprising a variant IgGFc domain is provided which exhibits an affinity for FcyRI receptor that is at least 2 fold, or at least 3 fold, or at least 5 fold, or at least 7 fold, or a least 10 fold, or at least 20 fold, or at least 30 fold, or at least 40 fold, or at least 50 fold, or at least 60 fold, or at least 70 fold, or at least 80 fold, or at least 90 fold, or at least 100 fold, or at least 200 fold less than a parent polypeptide comprising a wild type or modified wt Fc domain or is reduced to an undetectable level. In another aspect, a polypeptide comprising a variant IgG Fc domain is provided which exhibits an affinity for FcyRI receptor that is at least 90%, at least 80%, at least 70%, at least 60%, at least 50% less than a parent polypeptide comprising a wild type or modified wt Fc domain. In some aspects, the FcyRI is isoform FcyRIa. In other aspects, the FcyRI is isoform FcyRIb. In yet another aspect, the FcyRI is isoform FcyRIc.

[0176] In one aspect, a polypeptide comprising a variant IgG Fc domain is provided which exhibits a decreased affinity to FcyRII relative to a parent polypeptide comprising a wild type or modified wt Fc domain. In another aspect, a polypeptide comprising a variant IgGFc domain is provided which exhibits an affinity for FcyRII receptor that is at least 2 fold, or at least 3 fold, or at least 5 fold, or at least 7 fold, or a least 10 fold, or at least 20 fold, or at least 30 fold, or at least 40 fold, or at least 50 fold, or at least 60 fold, or at least 70 fold, or at least 80 fold, or at least 90 fold, or at least 100 fold, or at least 200 fold less than a parent polypeptide comprising a wild type or modified wt Fc domain.

[0177] In another aspect, a polypeptide comprising a variant IgG Fc domain is provided which exhibits an affinity for FcyRII receptor that is at least 90%, at least 80%, at least 70%, at least 60%, at least 50% less than a parent polypeptide comprising a wild type or modified wt Fc domain. In some aspects, the FcyRII is isoform FcyRIIa. In another aspect, the FcyRIIa isoform is allotype Hl 31. In yet another aspect, the FcyRIIa isoform is allotype R131. In other aspects, the FcyRII is isoform FcyRIIb. In some aspects, the FcyRIIb isoform is FcyRIIb-1. In other aspects, the FcyRIIb isoform is FcyRIIb-2. In yet another aspect, the FcyRII is isoform FcyRIIc.

[0178] In one aspect, a polypeptide comprising a variant IgG Fc domain is provided which exhibits a decreased affinity to FcyRIII relative to a parent polypeptide comprising a wild type or modified wt Fc domain. In another aspect, a polypeptide comprising a variant IgG Fc domain is provided which exhibits an affinity for FcyRIII receptor that is at least 2 fold, or at least 3 fold, or at least 5 fold, or at least 7 fold, or a least 10 fold, or at least 20 fold, or at least 30 fold, or at least 40 fold, or at least 50 fold, or at least 60 fold, or at least 70 fold, or at least 80 fold, or at least 90 fold, or at least 100 fold, or at least 200 fold less than a parent polypeptide comprising a wild type or modified wt Fc domain.

[0179] In another aspect, a polypeptide comprising a variant IgG Fc domain is provided which exhibits an affinity for FcyRIII receptor that is at least 90%, at least 80%, at least 70%, at least 60%, at least 50%, less than a parent polypeptide comprising a wild type or modified wt Fc domain. In some aspects, the FcyRIII is isoform FcyRIIIa. In other aspects, the FcyRIIIa is allotype 158V (Fl 58V allelic variant). In other aspects, the FcyRIIIa is allotype 158F. In other aspects, the FcyRIII is isoform FcyRIIIb. In another aspect, the FcyRIIIb is allotype NA1. In other aspects, the FcyRIIIb is allotype NA2.

[0180] In one aspect, a polypeptide comprising a variant IgG Fc domain is provided which exhibits a decreased affinity to FcRn relative to a parent polypeptide comprising a wild type or modified wt Fc domain. In another aspect, a polypeptide comprising a variant IgGFc domain is provided which exhibits an affinity for FcRn receptors that is at least 2 fold, or at least 3 fold, or at least 5 fold, or at least 7 fold, or a least 10 fold, or at least 20 fold, or at least 30 fold, or at least 40 fold, or at least 50 fold, or at least 60 fold, or at least 70 fold, or at least 80 fold, or at least 90 fold, or at least 100 fold, or at least 200 fold less than a parent polypeptide comprising a wild type or modified wt Fc domain. In another aspect, a polypeptide comprising a variant IgG Fc domain is provided which exhibits an affinity for FcRn receptors that is at least 90%, at least 80%, at least 70% , at least 60%, at least 50%, less than a parent polypeptide comprising a wild type or modified wt Fc domain.

[0181] In one aspect, a polypeptide comprising a variant IgG Fc domain is provided which exhibits an affinity for FcyR receptors, as measured by the dissociation constant (koff divided by kon, KD) that is between about 100 nM to about 100 pM, or about 100 nM to about 10 pM, or about 100 nM to about 1 pM, or about 1 nM to about 100 pM, or about 10 nM to about 100 pM, or about 1 pM to about 100 pM, or about 10 pM to about 100 pM. In certain aspects, a polypeptide comprising a variant IgG Fc domain is provided which exhibits an affinity for FcyR receptors that is greater than 1 pM, greater than 5 pM, greater than 10 pM, greater than 25 pM, greater than 50 pM, or greater than 100 pM. In another aspect, a polypeptide comprising a variant IgGFc domain is provided which exhibits an affinity for FcyR receptors that is less than 100 pM, less than 50 pM, less than 10 pM, less than 5 pM, less than 2.5 pM, less than 1 pM, or less than 100 nM, or less than 10 nM.

[0182] In one aspect, a polypeptide comprising a variant IgG Fc domain is provided which exhibits an affinity for FcRn receptors that is between about 100 nM to about 100 pM, or about 100 nM to about 10 pM, or about 100 nM to about 1 pM, or about 1 nM to about 100 pM, or about 10 nM to about 100 pM, or about 1 pM to about 100 pM, or about 10 pM to about 100 pM. In certain aspects, a polypeptide comprising a variant IgG Fc domain is provided which exhibits an affinity for FcRn receptors that is greater than 1 pM, greater than 5 pM, greater than 10 pM, greater than 25 pM, greater than 50 pM, or greater than 100 pM. In another aspect, a polypeptide comprising a variant IgG Fc domain is provided which exhibits an affinity for FcRn receptors that is less than 100 pM, less than 50 pM, less than 10 pM, less than 5 pM, less than 2.5 pM, less than 1 pM, or less than 100 nM, or less than 10 nM.

[0183] In specific aspects, a polypeptide comprising L234A / L235A or L234A / L235A / P331S or L234F / L235E / P331S orA236R / L328R substitutions in the IgG Fc domain which exhibits a decreased affinity to FcyR which further comprises I253A / H310A / H435A or I253A or H435A or H310A / H435Q substitutions in the IgGFc domain is provided which exhibits a decreased affinity to FcRn as compared to a parent polypeptide comprising a wild type or modified wt IgG Fc domain.

[0184] In specific aspects, a polypeptide comprising L234A / L235A or L234A / L235A / P331S or L234F / L235E / P331S orA236R / L328R substitutions in the IgG Fc domain which exhibits a fully ablated binding to FcyR which further comprises I253A / H310A / H435A or I253A or H435A or H310A / H435Q substitutions in the IgGFc domain is provided which exhibits a decreased affinity to FcRn as compared to a parent polypeptide comprising a wild type or modified wt IgG Fc domain.

[0185] In specific aspects, a polypeptide comprising L234A / L235A or L234A / L235A / P331S or L234F / L235E / P331S orA236R / L328R substitutions in the IgG Fc domain which exhibits a decreased affinity to FcyR which further comprises I253A / H310A / H435A or I253A or H435A or H310A / H435Q substitutions in the IgG Fc domain is provided which exhibits a fully ablated binding to FcRn as compared to a parent polypeptide comprising a wild type or modified wt IgG Fc domain.

[0186] In specific aspects, a polypeptide comprising L234A / L235A or L234A / L235A / P331S or L234F / L235E / P331S orA236R / L328R substitutions in the IgG Fc domain which exhibits a fully ablated binding to FcyR which further comprises I253A / H310A / H435A or I253A or H435A or H310A / H435Q substitutions in the IgG Fc domain is provided which exhibits a fully ablated binding to FcRn as compared to a parent polypeptide comprising a wild type or modified wt IgG Fc domain. In one aspect the invention relates to a molecule, such as an antibody or fragment thereof, which comprises a first polypeptide and a second polypeptide each comprising, in N-terminal to C- terminal direction at least a portion of an immunoglobulin hinge region, which comprises one or more cysteine residues, an immunoglobulin CH2- domain and an immunoglobulin CH3 -domain, wherein the first and the second polypeptides each comprise a mutation(s) from group A below and a mutation(s) from group B below,

[0187] A

[0188] (i) positions 234 and 235 are each substituted with alanine or

[0189] (ii) positions 234 and 235 are each substituted with alanine and position 331 is substituted with serine or

[0190] (iii) position 234 is substituted with phenylalanine, position 235 is substituted with glutamic acid and position 331 is substituted with serine or

[0191] (iv) position 328 is substituted with arginine and arginine is inserted after position 236; and

[0192] B

[0193] (i) position 253 is substituted with alanine or

[0194] (ii) position 435 is substituted with alanine or

[0195] (iii) positions 253, 310 and 435 are substituted with alanine or

[0196] (iv) position 310 is substituted with alanine and position 435 is substituted with glutamine

[0197] And wherein the first and second polypeptide may have the same or different mutations(s) (preferably the same), and wherein the mutations are defined with respect to the wild type or modified wt sequence as defined herein.

[0198] All features of the present disclosure apply to the above aspect Methods

[0199] In some aspects, a method to inhibit the maternofetal transfer ability in a parent polypeptide comprising an Fc domain comprising the steps of: a) (i) positions 234 and 235 are each substituted with alanine or

[0200] (ii) positions 234 and 235 are each substituted with alanine and position 331 is substituted with serine or

[0201] (iii) position 234 is substituted with phenylalanine, position 235 is substituted with glutamic acid and position 331 is substituted with serine or

[0202] (iv) position 328 is substituted with arginine and arginine is inserted after position 236; and b) (i) position 253 is substituted with alanine or

[0203] (ii) position 435 is substituted with alanine or

[0204] (iii) positions 253, 310 and 435 are substituted with alanine or

[0205] (iv) position 310 is substituted with alanine and position 435 is substituted with glutamine

[0206] Antibodies and Fragments Thereof

[0207] In some aspects, a binding molecule comprising a variant IgG Fc domain comprises an antigen binding domain that specifically binds to short soluble Endoglin (short sENG), or a fragment thereof, such as a C-terminal or N-terminal fragment of short sENG. In some specific aspects, the antigen-binding domain can be an antibody, e.g., a monoclonal antibody, or an antigen-binding fragment thereof. The antigen-binding domain can be a full-length antibody, e.g., a human antibody, a humanized antibody, or a chimeric antibody, or a fragment thereof.

[0208] The term "antibody variant" refers to a polypeptide containing a variant IgGFc domain provided herein, wherein the binding molecule is an antibody. Antibody variants include monoclonal antibodies, multispecific antibodies, human antibodies, humanized antibodies, camelized antibodies, chimeric antibodies, anti-idiotypic (anti-Id) antibodies, and Fc domain-containing fragments of any of the above. In some aspects, antibody variants include immunoglobulin molecules and immunologically active fragments of immunoglobulin molecules, i.e., molecules that contain an antigen binding site, wherein these fragments can be fused or conjugated to another immunoglobulin domain comprising a variant IgGFc domain provided herein. In one aspect, the antibody variants are of the human IgGl , IgG2, IgG3 or IgG4 isotype.

[0209] Antibody variants and fragments thereof comprising a variant IgG Fc domain provided herein can be from any animal origin including birds and mammals (e.g., human, a rodent such as mouse or rat, donkey, sheep, rabbit, goat, guinea pig, camel, horse, or chicken). In a specific aspect, an antibody variant is provided which is a human or a humanized monoclonal antibody. As used herein, "human" antibodies include antibodies having the amino acid sequence of a human immunoglobulin and also include antibodies isolated from human immunoglobulin libraries, synthetic immunoglobulin libraries in microorganisms or from mice or other birds or mammals that express antibodies from human genes.

[0210] An antibody variant can be monospecific, bispecific, trispecific or have greater specificity (multispecific antibodies). Multispecific antibody variants can specifically bind to different epitopes of desired target molecule or can specifically bind to both the target molecule as well as a heterologous epitope, such as a heterologous polypeptide or solid support material.

[0211] Specific therapeutic targets

[0212] Virtually any molecule can be targeted by a binding-molecule, e.g., an antibody, fusion protein, or conjugate comprising a variant IgG Fc domain according to the present invention. In additional, virtually any molecule can be incorporated into a fusion protein or a conjugate comprising a variant IgG Fc domain provided herein. However, as explained previously the variant IgG Fc domain of the present invention can be particularly useful for treating pregnant women.

[0213] Pregnancy comes with risks of severe complications and mobidity, even mortality. The Centers for Disease Control and Prevention (CDC) lists the following severe morbidity conditions: Acute myocardial infarction, Aneurysm, Acute renal failure, Adult respiratory distress syndrome, Amniotic fluid embolism, Cardiac arrest / ventricular fibrillation, Conversion of cardiac rhythm, Disseminated intravascular coagulation, Eclampsia, Heart failure / arrest during surgery or procedure, Puerperal cerebrovascular disorders, Pulmonary edema / Acute heart failure, Severe anesthesia complications, Sepsis and Shock

[0214] (https: / / www.cdc.gov / reproductivehealth / maternalinfanthealth / severematernalmorbiditv.html).

[0215] Even where treatments are available for these conditions in the population in general they are most likely not suitable, or proven safe, for the treatment of pregnant women due to the risk of maternofetal transfer and the potential adverse effects on the fetus. Many of the morbidities of pregnancy could be treated safely and effectively using antibodies, fusion proteins or conjugates comprising a variant IgG Fc domain according to the present invention.

[0216] Hypertension is a common condition in pregnancy and the underlying condition responsible for many of the morbidities of pregnancy. According to the Center for Disease Control about 10% of mothers hospitalized in 2004 in the US suffered hypertension. Hypertension during pregnancy can result in life-long circulatory damage, seizures and stroke in the mother and severe problems for the baby resulting from pre-term birth and low-birth weight. Hypertension, and pre- eclampsia / eclampsia in particular, are major causes of morbidity and mortality for mother and babies across the world and new treatments are clearly needed (Ives, C.W., et al, J. Am Coll Cardiol. 2020, 76: 1690-1702).

[0217] Hypertension, and pre-eclampsia / eclampsia, as well as other disorders of pregnancy seen in pregnant women, are well known and described in the common general knowledge textbooks such as, for example:

[0218] Sankaran S. Creasy and Resnik's Maternal-Fetal Medicine: Principles and Practice Sixth edition. Obstet Med. 2012 Jun; 5 (2): 88-9. doi: 10.1258 / om.2011.11E005. Epub 2012 Jun 19. PMCID: PMC4989620.

[0219] Magee, L. A., von Dadelszen, P., Stones, W., & Mathai, M. (2016). The FIGO Textbook of Pregnancy Hypertension: an evidence-based guide to monitoring, prevention and management.

[0220] Gestational Hypertension and Preeclampsia: ACOG Practice Bulletin, Number 222. Obstetrics &

[0221] Gynecology 135(6):p e237-e260, June 2020. | DOI: 10.1097 / AOG.0000000000003891 Saito, Shigeru 2018. Preeclampsia Basic, Genomic, and Clinical: Basic, Genomic, and Clinical

[0222] DOI - 10.1007 / 978-981-10-5891-2

[0223] These disorders found in pregnant women are described in Creasy and Resnik (above), which list of disorders and treatments is specifically incorporated by reference herein.

[0224] Hypertension complicates 5 to 10% of pregnancies and hypertensive disorders of pregnancy can be categorized as chronic, gestational or pre-eclamptic. Pre-eclampsia is especially serious being one of the top five causes of maternal and perinatal mortality. In 2005 it was estimated that worldwide pre-eclampsia claimed the lives of more than 70,000 women per year and more than 500,000 of their fetuses and newborns (Sabai, B., et al, Lancet 2005, 365: 785-99). There are also long term consequences after birth and it is estimated that worldwide, more than 300 million women and children are at increased risk of chronic health problems due to previous exposure to pre-eclampsia (Davis, E., et al., Pediatrics 2012, 129: el552).

[0225] Many compounds are available for the treatment of hypertension in the general population: in 2011 the FDA listed 69 approved drugs from 15 different drug classes (https: / / www.fda.gov / regulatory- information / search-fda-guidance-documents / hypertension-indication-drug-labeling- cardiovascular-outcome-claims ). However, none of these are specifically tested and approved for use during pregnancy and most, if not all, are small molecules or small peptide drugs which have a high possibility of crossing the placenta with unknown effects on the fetus.

[0226] Conventional medicines to control hypertension are sometimes used for the treatment of pregnant women but all of these have maternal or fetal risks, limited effectiveness, especially in the treatment of pre-eclampsia, and require a challenging risk-benefit evaluation with a severely limited set of data. Thus, there is a clear unmet need for therapies which treat hypertension and pre-eclampsia without exposing the fetus to harm or the risk of harm. This problem is solved by providing antibodies, fusion proteins or conjugates comprising a human variant IgG Fc domain according to the invention which can be developed to target and affect soluble proteins, receptors or small molecules that reduce, modulate or abolish or otherwise beneficially interfere with mechanisms of hypertension and pre-eclampsia. Currently available drugs to treat hypertension include Diuretics, Beta-blockers, ACE inhibitors, Angiotensin II receptor blockers, Calcium channel blockers, Alpha blockers Alpha-2 Receptor Agonists, Combined alpha and beta-blockers, Central nervous system agonists, Peripheral adrenergic inhibitors and Vasodilators. New drug classes including inhibitors of vasopeptidases, aldosterone synthase and soluble epoxide hydrolase, agonists of natriuretic peptide A and vasoactive intestinal peptide receptor 2, and a novel mineralocorticoid receptor antagonist are in phase II / III clinical development, while inhibitors of aminopeptidase A, dopamine P-hydroxylase, and the intestinal Na+ / H+ exchanger 3, agonists of components of the angiotensin converting enzyme 2 / angiotensin(l-7) / Mas receptor axis are in earlier stage development. Many of the underlying mechanisms of action of these classes of drugs can be amenable to the development of antibodies, fusion proteins or conjugates comprising a variant IgG Fc domain according to the present invention and thus safe for the treatment of pregnant women.

[0227] Treatment for pre-eclampsia, SGA and HELLP targeting short soluble endoglin (short sENG)

[0228] Pre-eclampsia is a disorder of pregnancy associated with new-onset hypertension, which occurs most often after 20 weeks of gestation and frequently near term. Several mechanisms of disease have been proposed in preeclampsia including the following: chronic uteroplacental ischemia, immune maladaptation, very low-density lipoprotein toxicity, increased trophoblast apoptosis or necrosis, and an exaggerated maternal inflammatory response to deported trophoblasts. Currently it is believed that imbalances of angiogenic factors are important in the pathogenesis of preeclampsia and a combination of some of the other purported mechanisms may be responsible for triggering the clinical spectrum of preeclampsia. For example, there is clinical and experimental evidence suggesting that uteroplacental ischemia leads to increased circulating concentrations of antiangiogenic factors, including soluble VEGF receptor- 1 (VEGFR-1) and soluble endoglin (sENG) which promote angiogenic imbalances.

[0229] Fetal growth restriction (FGR), also known as intrauterine growth restriction (IUGR), is a condition in pregnancy where a fetus does not grow to its genetic potential, often resulting in the baby being small for gestational age (SGA). SGA is typically defined as a fetal weight below the 1 Oth percentile for the given gestational age. The underlying causes of FGR can be broadly categorized into maternal, placental, and fetal factors. Maternal causes include chronic conditions such as hypertension, preeclampsia, malnutrition, and smoking. Placental factors involve issues like placental insufficiency, where the placenta fails to deliver adequate oxygen and nutrients to the fetus, leading to restricted growth. Fetal causes can include genetic abnormalities and infections.

[0230] Diagnosing FGR involves regular monitoring of fetal growth using ultrasound measurements. Key indicators include reduced fetal size for gestational age, abnormal Doppler flow studies (which assess blood flow in the umbilical artery), and oligohydramnios (reduced amniotic fluid). Once FGR is identified, management typically includes increased surveillance with non-stress tests or biophysical profiles to monitor fetal well-being, and sometimes early delivery if the fetal environment is deemed too compromised for continued development.

[0231] Infants born with FGR are at higher risk for numerous complications both immediately and longterm. In the neonatal period, they may face challenges such as hypoglycemia, temperature instability, and increased susceptibility to infections. Long-term risks include developmental delays, cardiovascular diseases, metabolic syndrome, and cognitive impairments (Westby, A., et al., American Family Physician 2021, 104:486-492). Increased levels of sENG are associated with FGR and SGA independently or in association with preeclampsia (Romero, R., et al., J. Maternal- Fetal and Neonatal Medicine 2008, 21:9-23).

[0232] HELLP syndrome is a severe pregnancy complication considered a variant of preeclampsia involving the breakdown of red blood cells, liver damage, and blood clotting issues, respectively (HELLP stands for Hemolysis, Elevated Liver enzymes, and Low Platelet count). The exact cause of HELLP syndrome is unknown, but it is believed to be related to preeclampsia. Risk factors include a history of preeclampsia or HELLP syndrome in previous pregnancies, high blood pressure, being over the age of 25, and multiple pregnancies such as twins or triplets. HELLP syndrome can lead to serious complications for both the mother and the baby, including liver rupture, kidney failure, stroke, placental abruption, and in severe cases, death.

[0233] The development of the placenta requires a complex interplay of new blood vessels to manage the transfer functions between mother and fetus which must coordinate with the increasing requirements as the fetus grows. Pre-eclampsia is considered a consequence of an imbalance in this process where the fetus is not sufficiently served with nutrients and oxygen and the balance of pro- and anti-angiogenic factors is upset. The sequalae of this imbalance can trigger general disruption to the maternal endothelium and invoke inappropriate immune responses. The anti- angiogenic factor soluble endoglin (sENG) is believed to be of prime importance in the pathogenesis of pre-eclampsia and HELLP syndrome, and thus prime a target for treatment using antibodies comprising a variant IgGFc domain according to the present invention (Venkatesha, S., et al., Soluble endoglin contributes to the pathogenesis of preeclampsia. Nature Medicine 2006, 12:642-649)

[0234] Endoglin is an essential endothelial cell co-receptor of the transforming growth factor 0 (TGF-0) superfamily consisting of type I and II serine / threonine kinase receptors that interact with TGF-0S and bone morphogenetic proteins. The most important ligands for endoglin are TGF-0 and bone morphogenetic protein (BMP)-9 which normally exist as homodimers. TGF 0 or BMP-9 bind to endoglin in a complex with type-II TGF 0 or BMP receptors which can then associate with activin- receptor like kinase (ALK)-l receptor. Phosphorylation of ALK-1 by the type-II receptor leads to downstream phosphorylation of the receptor-regulated Smads-1 / 5 / 8. Subsequent complex formation with Smad4 leads to the nuclear translocation of the Smad complex and the transcription of target genes, resulting in the regulation of angiogenesis. Activation of the endoglin-Smadl / 5 / 8 pathway indirectly inhibits the TGF0 signaling pathway, which involves another type-I receptor, ALK-5. ALK5 -dependent signaling leads to TGF 0 signaling and vessel maturation. Endoglin thus stimulates angiogenesis both directly through Smadl / 5 / 8 signaling and indirectly by inhibition of ALK-5 -mediated pathways. (Margioula-Siarkou, G, et al, The role of endoglin and ist soluble form in pathogenesis of preeclampsia. Mol. and Cell. Biochem. 2022, 477:479-491) In addition to the TGF-0 and BMP-9 regulation, endoglin expression is increased under hypoxic conditions. The is due to a hypoxia responsive element downstream of the endoglin promoter which, on binding hypoxia-inducible factor (HIF)-la, results in increased endoglin transcription (Sanchez-Elsner, T., et al, Endoglin Expression Is Regulated by Transcriptional Cooperation between the Hypoxia and Transforming Growth Factor- 0_ Pathways. J. Biol. Chem. 2002, 277:43799-43808).

[0235] Endoglin is a glycoprotein of 586 amino acids with a large extracellular domain (ECD) of 486 amino acids, a short trans-membrane sequence and a 47 amino acid intracellular region, although a minor variant of 14 amino acids has been identified. On the cell surface endoglin exists as a homodimer joined by two disulphide bridges adjacent to the membrane-spanning regions (2019 Saito).

[0236] Monoclonal antibodies to endoglin have been developed to target the new blood supply needed to support tumour growth or to deliver toxins to endoglin-rich tumours (W02010032059A3, WO2012149412A2 and W02010039873;TRC105). The most studies of these, TRC105, has been evaluated in more than 20 clinical trials for anti-tumour activity (clinical trials.gov). Based on animal models two mechanisms of action are proposed. Firstly, the antibody binds to cells carrying cell-surface endoglin and mediates ADCC resulting in the killing of target cells by NK cells, neutrophils and monocytes. Secondly, the antibody prevents binding of BMP-9 to the endoglin - receptor complex on the cell surface and inhibits stimulation of the Smads- 1 / 5 / 8 pathway pro- angiogenic pathway. Despite encouraging effects in animal models, TRC105 did not have a significant benefit in clinical trials and development is halted.

[0237] The endoglin extra-cellular domain can be cleaved from the cell-surface receptor and released into the circulation as soluble endoglin (sENG). sENG plasma levels are elevated in a variety of conditions including pre-eclampsia, hypertension, cardiovascular diseases, inflammatory conditions, and cancer (Aristrena, M., et al, MMP-12, Secreted by Pro-Inflammatory Macrophages, Targets Endoglin in Human Macrophages and Endothelial Cells. Int. J. of Molecular Sci. 2019, 20:3017-3026). The release of sENG is due to the action of proteases associated with the cell-membrane, notably MMP-14, and can be triggered by inflammation, hypoxia, tumour necrosis factor a (TNF-a), endothelial injury, or anti-endoglin antibodies. sENG-mediated effects include pro-inflammatory activity in endothelial cells, anti-angiogenic activity and increased vascular permeability, modulation of monocyte adhesion and transmigration, endothelial disfunction, and impaired vascular development.

[0238] Experimental and epidemiological studies support a pathological role for sENG in the imbalance of circulating angiogenic and anti-angiogenic factors in the aetiology of the maternal syndrome of pre-eclampsia. sENG plays a critical role in the development of preeclampsia by disrupting normal angiogenesis and promoting endothelial dysfunction. In preeclampsia, the placenta experiences hypoxia and oxidative stress, leading to an increased expression of both membrane-bound and soluble endoglin. This increase is mediated by hypoxia-inducible factors (HIF-la) and oxidative stress markers, which enhance the production of sENG. sENG functions as an anti-angiogenic factor by binding to and sequestering TGF-01, BMP-9, and BMP- 10. This binding reduces the bioavailability of these growth factors, thereby inhibiting their signaling pathways. TGF-0 signaling is essential for angiogenesis and vascular health, so its inhibition by sENG leads to impaired angiogenesis. Additionally, sENG interferes with the activation of endothelial nitric oxide synthase, resulting in decreased nitric oxide production. Nitric oxide is crucial for vasodilation and maintaining vascular tone, and its reduction leads to vasoconstriction and the hypertension characteristic of preeclampsia.

[0239] Moreover, sENG promotes endothelial dysfunction by facilitating vascular inflammation. It can bind to integrins on leukocytes, aiding their extravasation and triggering inflammatory responses that further contribute to endothelial damage. Elevated levels of sENG correlate strongly with the severity of preeclampsia, and its anti-angiogenic and pro-inflammatory effects are key factors in the development of the disease's clinical symptoms, including hypertension, proteinuria, and endothelial damage.

[0240] The diagnostic and therapeutic implications of sENG in preeclampsia are significant. Elevated sENG levels can serve as a biomarker for the early detection and severity assessment of preeclampsia. Measuring sENG levels in maternal blood may help predict the onset of preeclampsia weeks before clinical symptoms appear. Furthermore, therapeutic antibodies neutralizing the activity of sENG present a realistic treatment for preeclampsia, SGA and HELLP.

[0241] The concentration of sENG in the plasma of mothers whose fetus is identified as at risk of uterine growth restriction and small for gestational age, is elevated compared to that for women experiencing normal pregnancy. This elevation of sENG is continuous during pregnancy, unlike during preecalmpsia where the levels generally increase after about 25 weeks of gestation and then rise steeply towards about 32 weeks. Thus the sENG longitudinal profile is distinct from preeclampsia consistent with a different mechanism of action, compared to preeclampsia and HELLP. sENG plays a significant role in the pathophysiology of HELLP syndrome, a severe form of preeclampsia occurring during pregnancy. As an antiangiogenic factor, sENG inhibits the formation of new blood vessels, a process crucial for proper placental development. Elevated levels of sENG disrupt this process, leading to placental insufficiency and contributing to the development of HELLP syndrome. Additionally, sENG interferes with endothelial function by inhibiting the binding of transforming growth factor-beta (TGF-0) to its receptors on endothelial cells, leading to endothelial dysfunction. This dysfunction is a hallmark of preeclampsia and HELLP syndrome, contributing to hypertension, proteinuria, and systemic inflammatory responses.

[0242] The elevated levels of sENG are also associated with increased vascular permeability and hypertension, causing damage to multiple organs, including the liver and kidneys, which is characteristic of HELLP syndrome. Furthermore, sENG contributes to an exaggerated inflammatory response, leading to the activation of the coagulation system. This activation results in hemolysis, low platelet counts, and liver damage due to the infiltration of inflammatory cells.

[0243] Short sENG specific antibodies sENG usually refers to the full extracellular region of the membrane- spanning endoglin following proteolytic cleavage and release into the circulation. The sENG identified in the plasma of women experiencing preelampsia, fetal growth restriction or HELLP syndrome is of lower molecular weight compared to the released, full length extracellular domain. Therefore, the term “short sENG” is used herein to describe the truncated version of the molecule manifest in diseases and conditions of pregnancy. Short sENG may be a group of molecules of similar molecular weight, judged to be around 15kDa smaller than the extracellular domain. Short sENG is a monomer caused by the removal of the carboxy-terminal sequences which, in the extracellular domain, are linked by one or more disulphide bridges.

[0244] In order to make a monoclonal antibody selective for short sENG it is necessary to identify a binding site unique to the soluble molecule but inaccessible on the membrane-spanning endoglin. sENG is uniquely produced by the proteolytic cleavage of membrane-spanning endoglin and released as a disulphide-linked dimer (Saito, T., et al., Structural Basis of the Human Endoglin- BMP9 Interaction: Insights into BMP Signaling and HHT1. Cell Reports 2017 19: 1917-1928). However, short sENG from the plasma of preeclamptic women is a monomer and is truncated, compared to the monomer of the cleaved extra-cellular domain and henceforth referred to as ‘short sENG’ to distinguish from the disulphide-linked extracellular domain (see Lawera, A., et al., Role of soluble endoglin in BMP9 signaling. PNAS. 2019 116:17800-17808, Figure IE). Evidently sENG, after release by cleavage from membrane-spanning endoglin is further truncated by proteolysis. Based on the molecular weight of the species identified in a preeclamptic woman’s plasma, it is predicted that the site of cleavage is between the ZP-N and ZP-C domains. This exposes a new surface of ZP-N which is hidden in the membrane-spanning endoglin and in the proteolytically cleaved extracellular domain but, uniquely, exposed in short sENG.

[0245] A binding molecule of the disclosure comprising a Human variant IgG Fc domain can comprise any of the 4 mutation sets L234A / L235A, L234A / L235A / P331S, L234F / L235E / P331S orA236R / L328R designed to reduce FcyR binding, in combination with any one of the four mutations or mutation sets I253A / H310A / H435A or 1253 A or H435A or H310A / H435Q designed to reduce FcRn binding. The disclosure therefore relates to a polypeptide comprising any of these 16 individualised mutation sets- optionally in the form of a heavy chain or an antibody.

[0246] Other Drug Treatments

[0247] In another aspect, the approaches and uses described herein also applies to the treatment of a pregnant companion animal, such as dog or cat or horse, or a pregnant livestock animal such as a cow, sheep or goat. Therefore, it will be appreciated that such animals may be treated, and the invention is not limited to pregnant human women.

[0248] Methods of Producing Antibodies Comprising Variant IgG Fc Domains

[0249] Antibody variants or fragments thereof can be produced by any method known in the art for the synthesis of antibodies, in particular, by chemical synthesis or by recombinant expression techniques.

[0250] Monoclonal antibody variants can be prepared using a wide variety of techniques known in the art including the use of hybridoma, recombinant, and phage display technologies, or a combination thereof. For example, monoclonal antibody variants can be produced using hybridoma techniques including those known in the art. Methods for producing and screening for specific antibodies using hybridoma technology are routine and known in the art. Antibody variants can be generated by numerous methods well known to one skilled in the art. Non-limiting examples include, isolating antibody coding regions (e.g., from hybridomas) and introducing one or more Fc domain amino acid substitutions into the isolated antibody coding region. Alternatively, the variable regions can be subcloned into a vector encoding a variant IgG Fc domain provided herein.

[0251] Antibody variant fragments which recognize specific epitopes can be generated by any technique known to those of skill in the art. For some uses, including in vivo use of antibody variants in humans and in vitro detection assays, it can be advantageous to use human or chimeric antibody variants. Completely human antibodies are particularly desirable for therapeutic treatment of human subjects. Human antibodies or fragments thereof comprising a variant IgG Fc domain provided herein can be made by a variety of methods known in the art.

[0252] A chimeric antibody variant or fragment thereof comprising a variant IgG Fc domain provided herein can also be made by a variety of methods known in the art. In certain instances, a humanized antibody variant or fragment thereof can comprise a variant IgG Fc domain provided herein. Humanized antibody variants can be produced using variety of techniques known in the art, including but not limited to, CDR-grafting, veneering or resurfacing, etc.

[0253] Human antibody variants can also be produced using transgenic mice which are incapable of expressing functional endogenous immunoglobulins, but which can express human immunoglobulin genes. For example, the human heavy and light chain immunoglobulin gene complexes can be introduced randomly or by homologous recombination into mouse embryonic stem cells. Alternatively, the human variable region, constant region, and diversity region can be introduced into mouse embryonic stem cells in addition to the human heavy and light chain genes. The mouse heavy and light chain immunoglobulin genes can be rendered non-functional separately or simultaneously with the introduction of human immunoglobulin loci by homologous recombination. In particular, homozygous deletion of the JH region prevents endogenous antibody production. The modified embryonic stem cells are expanded and micro injected into blastocysts to produce chimeric mice. The chimeric mice are then bred to produce homozygous offspring that express human antibodies. The transgenic mice are immunized in the normal fashion with a selected antigen or immunogenic fragments thereof. Monoclonal antibodies directed against the antigen can be obtained from the immunized, transgenic mice using conventional hybridoma technology. The human immunoglobulin transgenes harbored by the transgenic mice rearrange during B cell differentiation, and subsequently undergo class switching and somatic mutation. Thus, using such a technique, it is possible to produce therapeutically useful antibodies.

[0254] Polynucleotides

[0255] A polynucleotide is provided which encodes a polypeptide that is a binding molecule, e.g. an antibody. Preferably, the binding molecule comprises a variant IgG Fc domain. Also provided is a polynucleotide that hybridizes under high stringency, intermediate, or lower stringency hybridization conditions to a polynucleotide that encodes said polypeptide.

[0256] In some aspects, a polynucleotide sequence encoding a said polypeptide c can be produced from a parent polynucleotide sequence obtained from a suitable source. Once the polynucleotide sequence has been obtained, the polynucleotide sequence can be manipulated using methods known in the art for the manipulation of nucleotide sequences, e.g., recombinant DNA techniques, site directed mutagenesis, PCR, etc. (see, for example, the techniques described in Sambrook et al., 1990, Molecular Cloning, A Laboratory Manual, 2d Ed., Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y. and Ausubel et al., eds., 1998, Current Protocols in Molecular Biology, John Wiley & Sons, NY, which are both incorporated by reference herein in their entireties), to generate a polypeptide comprising a variant IgG Fc domain having a different amino acid sequence, for example to create amino acid substitutions, deletions, and / or insertions.

[0257] In other aspects, a polynucleotide sequence encoding a said polypeptide, optionally comprising a variant IgG Fc domain, can be assembled from chemically synthesized oligonucleotides (e.g., as described in Kutmejer et al. BioTechniques 1994, 17: 242), which, briefly, involves the synthesis of overlapping oligonucleotides containing portions of the encoding sequence, annealing and ligating of those oligonucleotides, and then amplification of the ligated oligonucleotides by PCR.

[0258] Conjugates and Derivatives

[0259] In some aspects, an isolated binding molecule provided herein can be conjugated or fused to one or more moieties, including but not limited to, peptides, polypeptides, proteins, fusion proteins, nucleic acid molecules, small molecules, mimetic agents, synthetic drugs, inorganic molecules, and organic molecules.

[0260] In some aspects, a binding molecule of the disclosure includes derivatives that are modified, e.g., by covalent attachment of any type of molecule to the polypeptide or chemical or enzymatic modification. For example, derivatives include polypeptides that have been modified, e.g., by glycosylation, acetylation, phosphorylation, amidation, derivatization by known protecting / blocking groups, proteolytic cleavage, linkage to a cellular ligand or other protein, etc. Any of numerous chemical modifications can be carried out by known techniques, including, but not limited to, specific chemical cleavage, acetylation, formylation, etc. Additionally, the derivative can contain one or more non-classical amino acids.

[0261] Conjugates are provided which comprise a polypeptide comprising a variant IgG Fc domain chemically conjugated (including both covalent and non-covalent conjugations) to a heterologous protein or polypeptide (or fragment thereof, to a polypeptide of at least 10, at least 20, at least 30, at least 40, at least 50, at least 60, at least 70, at least 80, at least 90 or at least 100 amino acids). The conjugation does not necessarily need to be direct, but can occur through a linker. Such linker molecules are commonly known in the art and described in Denardo et al. Clin Cancer Res 1998, 4:2483; Peterson et al. Bioconjug. Chem. 1999, 10: 553; Zimmerman et al. Nucl. Med. Biol. 1999, 26: 943; Garnett, Adv. Drug Deliv. Rev. 2002, 53: 171.

[0262] Compositions comprising heterologous proteins, peptides or polypeptides conjugated to a polypeptide comprising a variant IgGFc domain are also provided.

[0263] In some aspects, an isolated binding molecule of the disclosure is conjugated to a diagnostic or detectable agent. Such conjugates can be useful for monitoring or prognosing the development or progression of an inflammatory disorder as part of a clinical testing procedure, such as determining the efficacy of a particular therapy. Such diagnosis and detection can be accomplished by coupling a polypeptide comprising a variant IgGFc domain to detectable substances.

[0264] In some aspects, an isolated binding molecule of the disclosure is conjugated to a therapeutic agent. A polypeptide comprising a variant IgG Fc domain can be conjugated to a therapeutic moiety such as a cytotoxin, a therapeutic agent or a radioactive metal ion. A cytotoxin or cytotoxic agent includes any agent that is detrimental to cells. Therapeutic agents or drug moieties are not to be construed as limited to classical chemical therapeutic agents. For example, the drug moiety can be a protein or polypeptide possessing a desired biological activity. Such proteins can include, for example, a toxin, a cytokine, or a growth factor. Moreover, an isolated binding molecule of the disclosure can be conjugated to a therapeutic moiety such as a radioactive material or a macrocyclic chelator useful for conjugating radioactive metal ions. Radioactive metals can be emitters of destructive radiation such as alpha particles for therapy or penetrating gamma radiation for diagnostic purposes. (https: / / world-nuclear.org / information-library / non-power-nuclear- applications / radioisotopes-research / radioisotopes-in-medicine.aspx).

[0265] An antibody comprising a variant IgGFc domain described herein, i.e., an antibody variant, can be conjugated to a therapeutic moiety. Techniques for conjugating therapeutic moieties to antibodies are well known, see, e.g., Arnon et al., "Monoclonal Antibodies For Immunotargeting Of Drugs In Cancer Therapy", in Monoclonal Antibodies And Cancer Therapy, Reisfeld et al. (eds.), pp. 243-56. (Alan R. Liss, Inc. 1985); Hellstrom et al., "Antibodies For Drug Delivery", in Controlled Drug Delivery (2nd Ed.), Robinson et al. (eds.), pp. 623-53 (Marcel Dekker, Inc. 1987); Thorpe, "Antibody Carriers Of Cytotoxic Agents In Cancer Therapy: A Review", in Monoclonal Antibodies 84: Biological And Clinical Applications, Pinchera et al. (eds.), pp. 475- 506 (1985); "Analysis, Results, And Future Prospective Of The Therapeutic Use Of Radiolabeled Antibody In Cancer Therapy", in Monoclonal Antibodies For Cancer Detection And Therapy, Baldwin et al. (eds.), pp. 303-16 (Academic Press 1985), and Thorpe et al. Immunol. Rev. 62: 119- 58 (1982). Alternatively, antibody variant can be conjugated to a second antibody to form an antibody heteroconjugate as described by Segal in U.S. Pat. No. 4,676,980 .

[0266] In some aspects, an isolated binding molecule of the disclosure comprises one or more engineered glycoforms, i.e., a carbohydrate composition that is covalently attached to the polypeptide. Engineered glycoforms can be useful for a variety of purposes, including but not limited to reducing effector function. Engineered glycoforms can be generated by any method known to one skilled in the art, for example by using engineered or variant expression strains, by co-expression with one or more enzymes, for example DI N-acetylglucosaminyltransferase III (GnTIl l), by expressing a polypeptide comprising a variant IgG Fc domain in various organisms or cell lines from various organisms, or by modifying carbohydrate(s) after a polypeptide comprising a variant IgG Fc domain has been expressed. Methods for generating engineered glycoforms are known in the art.

[0267] Fusion Proteins

[0268] An Fc fusion protein combines an Fc domain of an immunoglobulin or fragment thereof, with a fusion partner, which in general can be any protein, polypeptide, peptide, or small molecule. The role of the non-Fc part of the Fc fusion protein, i.e., the fusion partner, is often but not always to mediate target binding, and thus is functionally analogous to the variable regions of an antibody. Accordingly, a fusion protein, i.e., an isolated binding molecule of the disclosure and a fusion partner that specifically binds to a molecule (e.g., a cell surface receptor, chemokine, etc) is provided.

[0269] In some aspects, a fusion protein can comprise a peptide, polypeptide, protein scaffold, scFv, dsFv, diabody, Tandab, or an antibody mimetic fused to an isolated binding molecule of the disclosure. In some aspects, a fusion protein can comprise a linker region connecting a peptide, polypeptide, protein scaffold, scFv, dsFv, diabody, Tandab, or an antibody mimetic to a polypeptide comprising a variant IgG Fc domain. The use of naturally occurring as well as artificial peptide linkers to connect polypeptides into novel linked fusion polypeptides is well known in the literature.

[0270] In some aspects, a fusion protein can combine a variant IgG Fc domain with a fusion partner which in general can be a protein, including, but not limited to, a ligand, an enzyme, the ligand portion of a receptor, an adhesion protein, or some other protein or domain.

[0271] In another aspect, a fusion protein comprises a bioactive molecule fused to a variant IgG Fc domain described herein. Bioactive molecules that can be fused to a variant IgG Fc domain described herein, but are not limited to, peptides, polypeptides, proteins, small molecules, mimetic agents, synthetic drugs, inorganic molecules, and organic molecules. In one aspect, a bioactive molecule is a polypeptide comprising at least 5, at least 10, at least 20, at least 30, at least 40, at least 50, at least 60, at least 70, at least 80, at least 90 or at least 100 contiguous amino acid residues, and is heterologous to the amino acid sequence of a variant IgG Fc domain described herein.

[0272] A fusion protein comprising a variant IgG Fc domain described herein can be fused to a marker sequence, such as but not limited to, a peptide, to facilitate purification. In some aspects, the marker amino acid sequence is a His6 tag, a "flag" tag, a hemagglutinin "HA" tag, or one of many others commercially available tags.

[0273] A variety of linkers can be used to covalent link a polypeptide comprising a variant IgG Fc domain to a fusion partner to generate a fusion protein. Alternatively, polypeptides, proteins and fusion proteins can be produced by standard recombinant DNA techniques or by protein synthetic techniques, e.g., by use of a peptide synthesizer.

[0274] Recombinant Polypeptide Expression

[0275] The recombinant expression of an isolated binding molecule of the disclosure, derivative, analog or fragment thereof, e.g., an antibody variant or a fusion protein comprising a variant IgG Fc domain described herein, can be accomplished through the construction of an expression vector containing a polynucleotide that encodes the polypeptide. Once a polynucleotide encoding a polypeptide comprising a variant IgGFc domain (e.g., an antibody variant or a fusion protein) has been obtained, the vector for the production of the polypeptide can be produced by recombinant DNA technology using techniques well known in the art.

[0276] Thus, methods for preparing a protein by expressing a polynucleotide containing a nucleotide sequence encoding a polypeptide binding molecule of the disclosure (e.g., an antibody variant or a fusion protein) are described herein. Methods that are well known to those skilled in the art can be used to construct expression vectors containing coding sequences and appropriate transcriptional and translational control signals. These methods include, for example, in vitro recombinant DNA techniques, synthetic techniques, and in vivo genetic recombination. Thus, replicable vectors are provided which comprise a nucleotide sequence encoding a polypeptide comprising a variant IgGFc domain, operably linked to a promoter.

[0277] The expression vector is transferred to a host cell by conventional techniques and the transfected cells are then cultured by conventional techniques to produce a polypeptide comprising a variant IgG Fc domain. Thus, host cells are provided which contain a polynucleotide encoding a polypeptide comprising a variant IgGFc domain, operably linked to a heterologous promoter.

[0278] A variety of host-expression vector systems can be utilized to express a polypeptide comprising a variant IgG Fc domain. Such host-expression systems represent vehicles by which the coding sequences of interest can be produced and subsequently purified, but also represent cells which can, when transformed or transfected with the appropriate nucleotide coding sequences, express a polypeptide comprising a variant IgGFc domain in situ. These include but are not limited to microorganisms such as bacteria (e.g., E. coli and B. subtilis) transformed with recombinant bacteriophage DNA, plasmid DNA or cosmid DNA expression vectors containing a sequence or sequences encoding a polypeptide comprising a variant IgGFc domain; yeast (e.g., Saccharomyces Pichia) transformed with recombinant yeast expression vectors containing a sequence or sequences encoding a binding molecule of the disclosure; insect cell systems infected with recombinant virus expression vectors (e.g., baculovirus) containing a sequence or sequences encoding a binding molecule of the disclosure; plant cell systems infected with recombinant virus expression vectors (e.g., cauliflower mosaic virus, CaMV; tobacco mosaic virus, TMV) or transformed with recombinant plasmid expression vectors (e.g., Ti plasmid) containing a sequence or sequences encoding a binding molecule of the disclosure; or mammalian cell systems (e.g., COS, CHO, BHK, 293, NSO, 3T3 cells) harboring recombinant expression constructs containing promoters derived from the genome of mammalian cells or from mammalian viruses.

[0279] A host cell strain can be chosen which modulates the expression of the inserted sequences, or modifies and processes the gene product in the specific fashion desired. Such modifications (e.g., glycosylation) and processing (e.g., cleavage) of protein products can be important for the function of the protein. Different host cells have characteristic and specific mechanisms for the post-translational processing and modification of proteins and gene products. Eukaryotic host cells which possess the cellular machinery for proper processing of the primary transcript, glycosylation, and phosphorylation of the gene product can be used. Such mammalian host cells include but are not limited to CHO, VERY, BHK, PER.C6, HeLa, COS, MDCK, 293, 3T3, W138, BT483, Hs578T, HTB2, BT20 and T47D, NSO, CRL7O3O and HsS78Bst cells.

[0280] For long-term, high-yield production of recombinant proteins, stable expression is often preferred. For example, cell lines which stably express a polypeptide comprising a variant IgG Fc domain can be engineered using methods known in the art.

[0281] Once a binding molecule of the disclosure (e.g., an antibody variant or a fusion protein) has been produced by recombinant expression, it can be purified by any method known in the art for purification of a protein, for example, by chromatography (e.g., ion exchange, affinity, particularly by affinity for the specific antigen after Protein A, and sizing column chromatography), centrifugation, differential solubility, or by any other standard technique for the purification of proteins.

[0282] Characterization and Functional Assays

[0283] An isolated binding molecule as described herein can be characterized in a variety of ways. In particular, a binding molecule can be assayed for the ability to specifically bind to a ligand, e.g., FcyRIIb, FcyRIIIa(158V), FcRn. Such an assay can be performed in solution (see, e.g., Houghten, Bio / Techniques 13:412-421 (1992)), on beads (see, e.g., Lam, Nature 354:82-84 (1991)), on chips (see, e.g., Fodor, Nature 364:555-556 (1993)), on bacteria (see, e.g., U.S. Pat. No. 5,223,409 ), on plasmids (see, e.g., Cull et al., Proc. Natl. Acad. Sci. USA 89: 1865-1869 (1992)), or on phage (see, e.g., Scott and Smith, Science 249:386-390 (1990); Devlin, Science 249:404-406 (1990); Cwirla et al., Proc. Natl. Acad. Sci. USA 87:6378- 6382 (1990); and Felici, J. Mol. Biol. 222:301-310 (1991)). Molecules that have been identified to specifically bind to a ligand, e.g., FcyRIIb, FcyRIIIa, FcRn can then be assayed for their affinity for the ligand.

[0284] A binding molecule of the disclosure can be assayed for specific binding to a molecule such as an antigen (e.g., cancer antigen and cross-reactivity with other antigens) or a ligand (e.g., FcyR) by any method known in the art. Immunoassays which can be used to analyze specific binding and cross-reactivity include, but are not limited to, competitive and non-competitive assay systems using techniques such as western blots, radioimmunoassays, ELISA (enzyme linked immunosorbent assay), "sandwich" immunoassays, immunoprecipitation assays, precipitin reactions, agglutination assays, complement-fixation assays, fluorescent immunoassays, protein A immunoassays, etc. Such assays are routine and well known in the art. See, e.g., Ausubel et al., eds, 1994, Current Protocols in Molecular Biology, Vol. 1, John Wiley & Sons, Inc., New York.

[0285] The binding affinity of an isolated binding molecule of the disclosure to a molecule such as an antigen or a ligand, e.g., FcyR, and the off-rate of the interaction can be determined by competitive binding assays. The kinetic parameters of a polypeptide comprising a variant IgG Fc domain can also be determined using any surface plasmon resonance (SPR) based assays known in the art (e.g., BIAcore or ProteOn kinetic analysis). See, e.g., Mullet et al. Methods 22: 77-91 (2000); Dong et al. Rev. Mol. Biotech. 82: 303-23 (2002); Fivash et al. Curr. Opin. Biotechnol. 9: 97-101 (1998); Rich et al. Curr. Opin. Biotechnol. 11 : 54-61 (2000). Additionally, any of the SPR instruments and SPR based methods for measuring protein-protein interactions described in U.S. Pat. Nos. 6, 373, 577 ; 6, 289, 286 ; 5, 322, 798 ; 5, 341, 215 ; 6, 268, 125 are contemplated in the methods of the present disclosure.

[0286] Fluorescence activated cell sorting (FACS), using any of the techniques known to those skilled in the art, can be used for characterizing the binding of a polypeptide comprising a variant IgG Fc domain to a molecule expressed on the cell surface (e.g., a FcyR).

[0287] A polypeptide comprising a variant IgG Fc domain can be assayed for its ability to mediate FcyR- mediated effector cell function. Examples of effector cell functions that can be assayed include, but are not limited to, antibody-dependent cell mediated cytotoxicity (ADCC), Clq binding, and complement dependent cell mediated cytotoxicity (CDC). Any cell-based or cell free assay known to those skilled in the art for determining effector cell function activity can be used (see, e.g., Perussia et al. Methods Mol. Biol. 121: 179-92 (2000); Baggiolini et al. Experientia 44: 841-8 (1998); Lehmann et al. J. Immunol. Methods 243: 229-42 (2000); Brown, Methods Cell Biol. 45: 147-64 (1994); Munn et al. J. Exp. Med. 172: 231-237 (1990); Abdul-Majid et al. Scand. J. Immunol. 55:70-81 (2002); Ding et al. Immunity 8:403-411 (1998)). In particular, a polypeptide comprising a variant IgG Fc domain can be assayed for FcyR-mediated ADCC activity in effector cells, e.g., natural killer cells, using any of the standard methods known to those skilled in the art (see, e.g., Perussia et al. Methods Mol. Biol. 121: 179-92 (2000)).

[0288] Pharmaceutical Compositions and Methods of Administration

[0289] In another aspect, pharmaceutical compositions are provided which comprise a binding molecule that specifically binds to short sENG, optionally comprising a variant IgG Fc domain as described herein, or a conjugate as described herein or a vector as described herein, or combinations thereof formulated together with a carrier, and a pharmaceutically acceptable excipient.

[0290] In another aspect, compositions are provided which comprise a binding molecule that specifically binds to short sENG, optionally comprising a variant IgGFc domain as described herein, a nucleic acid encoding a binding molecule that specifically binds to short sENG, optionally comprising a variant IgG Fc domain as described herein, or combinations thereof formulated together with a carrier. Such compositions can include one or a combination of (e.g., two or more different) antibodies, fusion proteins, or conjugates. In some aspects, such compositions are physiologically tolerable and as such are suitable for therapeutic, prophylactic, or diagnostic administration to a subject.

[0291] In another aspect, compositions comprising a binding molecule that specifically binds to short sENG, optionally comprising a variant IgGFc domain, (e.g., an antibody variant, a fusion protein, or a conjugate) or a nucleic acid encoding a binding molecule that specifically binds to short sENG, optionally comprising a variant IgG Fc domain, can include one or more pharmaceutically acceptable salts.

[0292] Examples of suitable aqueous and nonaqueous carriers that can be employed in contemplated compositions include water, ethanol, polyols (such as glycerol, propylene glycol, polyethylene glycol, and the like), and suitable mixtures thereof, vegetable oils, such as olive oil, and injectable organic esters, such as ethyl oleate. Proper fluidity can be maintained, for example, by the use of coating materials, such as lecithin, by the maintenance of the required particle size in the case of dispersions, and by the use of surfactants.

[0293] In another aspect, compositions comprising a binding molecule that specifically binds to short sENG, optionally comprising a variant IgGFc domain, (e.g., an antibody variant, a fusion protein, or a conjugate) or a nucleic acid encoding a binding molecule that specifically binds to short sENG, optionally comprising a variant IgG Fc domain, can also contain agents such as preservatives, wetting agents, emulsifying agents and dispersing agents. Prevention of presence of microorganisms can be ensured both by sterilization procedures and by the inclusion of various antibacterial and antifungal agents, for example, paraben, chlorobutanol, phenol, sorbic acid, and the like. It can also be desirable to include isotonic agents, such as sugars, sodium chloride, and the like into the compositions. In addition, prolonged absorption of the injectable pharmaceutical form can be brought about by the inclusion of agents which delay absorption such as aluminum monostearate and gelatin.

[0294] Pharmaceutically acceptable carriers include sterile aqueous solutions or dispersions and sterile powders for the extemporaneous preparation of sterile injectable solutions or dispersion. The use of such media and agents for pharmaceutically active substances is known in the art. Except insofar as any conventional media or agent is incompatible with the active compound, use thereof in the pharmaceutical compositions is contemplated. Supplementary active compounds can also be incorporated into the compositions. In some aspects, acceptable carriers include excipients approved for or considered to be safe for human and animal administration, i.e., GRAS substances (generally regarded as safe). GRAS substances are listed by the Food and Drug administration in the Code of Federal Regulations (CFR) at 21 CFR 182 and 21 CFR 184, incorporated herein by reference.

[0295] Actual dosage levels of the active ingredients in pharmaceutical compositions comprising a polypeptide comprising a variant IgG Fc domain (e.g., an antibody variant, a fusion protein, or a conjugate) or a nucleic acid encoding a polypeptide comprising a variant IgG Fc domain can be varied so as to obtain an amount of the active ingredient which is effective to achieve the desired therapeutic response for a particular patient, composition, and mode of administration, without being toxic to the patient. The selected dosage level will depend upon a variety of pharmacokinetic factors including the activity of the particular compositions employed, or the ester, salt or amide thereof, the route of administration, the time of administration, the rate of excretion of the particular compound being employed, the duration of the treatment, other drugs, compounds and / or materials used in combination with the particular compositions employed, the age, sex, weight, condition, general health and prior medical history of the patient being treated, and like factors well known in the medical arts.

[0296] A therapeutically effective dosage of a binding molecule that specifically binds to short sENG, optionally comprising a variant IgG Fc domain, a nucleic acid encoding a binding molecule that specifically binds to short sENG, optionally comprising a variant IgG Fc domain, or a pharmaceutical composition thereof results in a decrease in severity of disease symptoms, an increase in frequency and duration of disease symptom-free periods, or a prevention of impairment or disability due to the disease affliction. A therapeutically effective dose can also prevent or delays onset of disease. Accordingly, any clinical or biochemical monitoring assay can be used to determine whether a particular treatment is a therapeutically effective dose. One of ordinary skill in the art would be able to determine such amounts based on such factors as the subject's size, the severity of the subject's symptoms, and the particular composition or route of administration selected. A composition comprising a binding molecule that specifically binds to short sENG, optionally comprising a variant IgGFc domain, (e.g., an antibody variant, a fusion protein, or a conjugate) or a nucleic acid encoding a binding molecule that specifically binds to short sENG, optionally comprising a variant IgGFc domain, can be administered via one or more routes of administration using one or more of a variety of methods known in the art. As will be appreciated by the skilled artisan, the route and / or mode of administration will vary depending upon the desired results. Selected routes of administration compositions comprising a binding molecule that specifically binds to short sENG, optionally comprising a variant IgG Fc domain, a nucleic acid encoding a binding molecule that specifically binds to short sENG, optionally comprising a variant IgG Fc domain , and pharmaceutical compositions thereof include intravenous, intramuscular, intradermal, intraperitoneal, subcutaneous, spinal or other parenteral routes of administration, for example by injection or infusion. Parenteral administration can represent modes of administration other than enteral and topical administration, usually by injection, and includes, without limitation, intravenous, intramuscular, intraarterial, intrathecal, intracapsular, intraorbital, intracardiac, intradermal, intraperitoneal, transtracheal, subcutaneous, subcuticular, intraarticular, subcapsular, subarachnoid, intraspinal, epidural and intrasternal injection and infusion. Alternatively, compositions comprising a binding molecule that specifically binds to short sENG, optionally comprising a variant IgG Fc domain, a nucleic acid encoding a binding molecule that specifically binds to short sENG, optionally comprising a variant IgG Fc domain, and pharmaceutical compositions thereof can be administered via a non-parenteral route, such as a topical, epidermal or mucosal route of administration, for example, intranasally, orally, vaginally, rectally, sublingually or topically.

[0297] Methods of Treatment

[0298] A binding molecule that specifically binds to short sENG, optionally comprising a variant IgGFc domain, (e.g., an antibody variant, a fusion protein, or a conjugate) or a nucleic acid encoding a binding molecule that specifically binds to short sENG, optionally comprising a variant IgG Fc domain, can be administered to an animal, in particular a mammal, specifically, a human, preferably a woman, more preferably a pregnant woman for preventing, treating, or ameliorating one or more symptoms associated with a disease, disorder, or infection. A binding molecule that specifically binds to short sENG, optionally comprising a variant IgGFc domain, or a nucleic acid encoding a binding molecule that specifically binds to short sENG, optionally comprising a variant IgG Fc domain, can be particularly useful for the treatment or prevention of diseases or disorders related to pregnancy.

[0299] A binding molecule that specifically binds to short sENG, optionally comprising a variant IgGFc domain, or a nucleic acid encoding a binding molecule that specifically binds to short sENG, optionally comprising a variant IgGFc domain, and compositions thereof can be particularly useful for the treatment or prevention of hypertension-related conditions or pre-eclampsia / eclampsia.

[0300] A binding molecule that specifically binds to short sENG, optionally comprising a variant IgGFc domain, or a nucleic acid encoding a binding molecule that specifically binds to short sENG, optionally comprising a variant IgG Fc domain, can be provided in pharmaceutically acceptable compositions as known in the art or as described herein. As detailed below, a binding molecule that specifically binds to short sENG, optionally comprising a variant IgG Fc domain, or a nucleic acid encoding a binding molecule that specifically binds to short sENG, optionally comprising a variant IgG Fc domain, can be used in methods of treating or preventing hypertension-related conditions or pre-eclampsia / eclampsia.

[0301] A binding molecule that specifically binds to short sENG, optionally comprising a variant IgGFc domain, or a nucleic acid encoding a binding molecule that specifically binds to short sENG, optionally comprising a variant IgG Fc domain, and compositions thereof can also be advantageously utilized in combination with other therapeutic agents known in the art for the treatment or prevention of hypertension-related conditions or pre-eclampsia / eclampsia. A binding molecule that specifically binds to short sENG, optionally comprising a variant IgGFc domain, or a nucleic acid encoding a binding molecule that specifically binds to short sENG, optionally comprising a variant IgG Fc domain, and compositions thereof can also be advantageously utilized in combination with one or more drugs used to treat a disease, disorder, or infection such as, for example anti-cancer agents, anti-inflammatory agents or anti-viral agents.

[0302] In some aspects, methods for preventing, treating, or ameliorating one or more symptoms associated with hypertension-related conditions or pre-eclampsia / eclampsia and related conditions by administering a binding molecule that specifically binds to short sENG, optionally comprising a variant IgG Fc domain, or a nucleic acid encoding a binding molecule that specifically binds to short sENG, optionally comprising a variant IgGFc domain, are provided.

[0303] The disclosure also encompasses methods for treating or preventing hypertension-related conditions or pre-eclampsia / eclampsia in a subject comprising administering a therapeutically or prophylactically effective amount of a binding molecule that specifically binds to short sENG, optionally comprising a variant IgGFc domain.

[0304] In another aspect, a binding molecule that specifically binds to short sENG, optionally comprising a variant IgG Fc domain, or a nucleic acid encoding a binding molecule that specifically binds to short sENG, optionally comprising a variant IgG Fc domain, or a conjugate and compositions thereof for use in therapy of a mammal, preferably a human, more preferably a woman, even more preferably a pregnant woman is provided and preferably for treating or preventing hypertension- related conditions or pre-eclampsia / eclampsia.

[0305] Kits

[0306] Also provided is a pharmaceutical pack or kit comprising one or more containers filled with one or more of the pharmaceutical compositions disclosed herein. Optionally associated with such container(s) can be a notice in the form prescribed by a governmental agency regulating the manufacture, use or sale of pharmaceuticals or biological products, which notice reflects approval by the agency of manufacture, use or sale for human administration. The present disclosure provides kits that can be used in the above methods of treatment and administration. In one aspect, a kit comprises a binding molecule that specifically binds to short sENG, optionally comprising a variant IgG Fc domain, (e.g., an antibody variant, a fusion protein, or a conjugate), preferably in a purified form, in one or more containers.

[0307] Examples

[0308] Materials and General Methods.

[0309] The assignment of amino acids for antibody sequences uses the following numbering systems: Kabat numbering is used for the variable domains (Kabat, E.A., et al, Sequences of Proteins of Immunological Interest, 5th ed., Public Health Service, National Institutes of Health, Bethesda, MD (1991)) and the Eu numbering scheme is used for constant domains (Edelman, G.M., et al., Proc. Natl. Acad. Sci. USA 63 (1969) 78-85). Specifically, the Eu numbering scheme (see Kabat pages 661-723) is used for the constant heavy chain domains (CHI, Hinge, CH2 and CH3).

[0310] In accordance with the present invention there may be employed conventional molecular biology, microbiology, protein expression and purification, antibody, and recombinant DNA techniques within the skill of the art. Such techniques are explained fully in the literature. See, e.g., Sambrook, J., et al. (2001) Molecular Cloning: A Laboratory Manual. 3rd ed. Cold Spring Harbor Laboratory Press: Cold Spring Harbor, New York; Ausubel et al. eds. (2005) Current Protocols in Molecular Biology. John Wiley and Sons, Inc.: Hoboken, NJ; Bonifacino et al. eds. (2005) Current Protocols in Cell Biology. John Wiley and Sons, Inc.: Hoboken, NJ; Coligan et al. eds. (2005) Current Protocols in Immunology, John Wiley and Sons, Inc.: Hoboken, NJ; Coico et al. eds. (2005) Current Protocols in Microbiology, John Wiley and Sons, Inc. : Hoboken, NJ; Coligan et al. eds. (2005) Current Protocols in Protein Science, John Wiley and Sons, Inc.: Hoboken, NJ; and Enna et al. eds. (2005) Current Protocols in Pharmacology, John Wiley and Sons, Inc.: Hoboken, NJ.; Nucleic Acid Hybridization, Hames & Higgins eds. (1985); Transcription And Translation, Hames & Higgins, eds. (1984); Animal Cell Culture Freshney, ed. (1986); Immobilized Cells And Enzymes, IRL Press (1986); Perbal, A Practical Guide To Molecular Cloning (1984); and Harlow and Lane. Antibodies: A Laboratory Manual (Cold Spring Harbor Laboratory Press: 1988). Antibodies are routinely expressed and purified from mammalian cells, HEK293 and CHO typically, but other expression systems such as yeast, plant cells and E.coli can also be used (Frenzel, A., et al; Expression of Recombinant Antibodies; Frontiers in Immunology: 2013, 4, Article 271 : 1-20).

[0311] Genetic constructs and plasmids.

[0312] Gene sequences for expression of antibody chains and other desired sequences can be codon- optimised, synthesised and sequence-confirmed by contractors such as the Geneart Services provided by Thermofisher Scientific (https : / / www. thermofisher, com / ch / en / home / life- science / cloning / gene-synthesis.html). Desired sequences for DNA synthesis are provided electronically and after codon optimisation for the appropriate expression system are synthesised and checked by DNA sequencing.

[0313] Confirmed sequences are then cloned into a suitable plasmid such as pcDNA3.4-TOPO from Thermofisher Scientific, engineered to support transient expression of target proteins in mammalian cell culture. The pcDNA3.4-TOPO incorporates features and control sequences which allow: PCR-amplified and insertion of the target gene sequence; E.coli amplification and selection for correct plasmids; plasmid purification and linearisation; transfection of mammalian cells and high level production and secretion of the target protein. In the specific instance of the pcDNA3.4- TOPO plasmid the necessary features are: WPRE (Woodchuck posttranscriptional regulatory element) downstream of the cloning site to enhance transcript expression; full-length human cytomegalovirus (CMV) immediate-early promoter / enhancer for high-level gene expression in mammalian cells - HEK 293 or CHO for example; TOPO cloning site for rapid and efficient cloning of Tag-amplified PCR products; Herpes Simplex Virus thymidine kinase polyadenylation signal for proper termination and processing of the recombinant transcript; neomycin resistance gene for selection of stable cell lines with the antibiotic geneticin; pUC origin for high copy replication and maintenance of the plasmid in E. coir, and ampicillin (bla) resistance gene for selection in E. coli. Other plasmids with similar design features can be utilised and are commonly available.

[0314] In the following Examples, the chimeric antibody with the parent heavy chain (SEQ ID NO: 11) and the light chain (SEQ ID NO: 12) is designated MOm601 and also known as WBP71785_1.

[0315] The chimeric antibody with the substitutions I253A+H310A+H435A / L234F+L235E+P331S in the heavy chain (SEQ ID NO: 13) and the light chain (SEQ ID NO: 12) is designated MOm603.

[0316] The humanised / deimmunised antibody with the parent sequence heavy chain (SEQ ID NO: 15) and the light chain (SEQ ID NO: 16) is designated M0m611.

[0317] The humanised / deimmunised antibody with the substitutions I253A+H310A+H435A / L234F+L235E+P331S in the heavy chain (SEQ ID NO: 17) and the light chain (SEQ ID NO: 16) is designated MOm613.

[0318] The humanised antibody with the parent sequence heavy chain (SEQ ID NO: 19) and the light chain (SEQ ID NO: 20) is designated MOm621.

[0319] The antibody with the substitutions I253A+H310A+H435A / L234F+L235E+P331S in the heavy chain (SEQ ID NO: 21) and the light chain (SEQ ID NO: 20) is designated MOm623 and also known as WBP71785_2. Example 1: Design of Immunogens based on the predicted sequence of short sENG

[0320] It is a necessary step to design tailored immunogens for generation of sENG monoclonal antibodies specific for the truncated sENG found in conditions of pregnancy including preeclampsia, SGA and HELLP syndrome.

[0321] The sequence and structure of endoglin is known: https: / / www.uniprot.org / uniprotkb / Pl 7813 / entry. It is composed of an N-terminal orphan region (OR), a C-terminal two-domain zona pellucida module (ZP), a single transmembrane domain, and a short cytoplasmic peptide that differs in the L and S isoforms of the protein. Cleavage of the full extracellular domain generates sENG. The ZP module of the extracellular domain is divided into the ZP-N domain linked to the ZP-C domain by a short linker comprising amino acids 444 to 447. Cleavage of this linker is the likely process whereby the full extracellular domain of endoglin is cleaved to the short sENG version detected in preeclampsia, SGA and HELLP syndrome. Cleavage of the linker reveals a surface of ZP-N which is normally internal in the intact molecule and thus uniquely exposed in the short sENG. Antibodies which recognise this new exposed portion of sENG will therefore bind only short sENG and not the extracellular domain sENG or membranespanning endoglin.

[0322] Generation of immunogen

[0323] Immunogens for immunising animals to generate monoclonal antibodies are normally expressed as proteins, then injected with adjuvants into the target species, or injected directly as nucleic acid constructs which express the target protein. Thus, a number of constructs are designed to express the protein immunogen terminating in the ZP-N domain including ZP-N as an isolated protein, the full amino-terminal sequence of the extracellular domain but truncated at amino acid 444 and a carrier protein, maltose binding protein, for example, fused to the amino-terminus of the extracellular domain or the amino terminus of the ZP-N domain, for example, amino acid 349. Protein constructs are also tagged at the amino-terminus to facilitate purification of the expressed proteins. Mice are then immunised with a suitable protein immunogen or the equivalent DNA sequence. Example 2: Selection of antibodies

[0324] Hybridoma generation and screening

[0325] Four mice are immunised with a suitable immunogen, e.g. as described in Example 1, and serum titre monitored using an ELISA assay to the target protein. Mice with the highest titre are chosen for hybridoma fusion with SP2 / 0 mouse myeloma cells by electrofusion with 4096-well plates per single fusion. The supernatants from each plate are screened by ELISA for binding to the target molecule. Antibodies with bind to the target are counter-screened by FACS against a cell line expressing membrane-spanning endoglin, for example, HMEC-1 cells (https: / / www.atcc.org / products / crl-3243). Antibodies that are specific for short sENG can thus be separated from antibodies that bind the membrane- spanning endoglin and the extracellular sENG.

[0326] Hybridomas selected for specific short sENG binding are subcloned to obtain single clones, using semisolid methods, and sixteen subclones rescreened for binding to short sENG and negatively selected against the endoglin-expressing cell line. Positive clones are selected for antibody sequencing. Murine monoclonal antibodies having the desired specificity of the invention, that is, binding only to short sENG, not the membrane- spanning endoglin, are exemplified.

[0327] Example 3: Design of immunogens based on the experimentally-determined carboxy terminal sequence of short sENG

[0328] Samples of plasma from women experiencing preeclampsia and HELLP syndrome are obtained following the appropriate guidelines and permissions. The level of short sENG in the samples is confirmed by protein blot analysis, following electrophoresis under denaturing conditions, using a suitable detection antibody, for example IMC-19F.

[0329] Plasma samples containing sufficient short sENG are pooled and the target protein captured by immunoprecipitation. IMC-19F is an antibody which binds to the ligand-binding site of endoglin and therefore binds to short sENG. A suitable immunoprecipitation protocol is described by Thermofisher where the binding antibody is immobilised to magnetic beads. The washed beads are then incubated with the patient plasma samples to bind short sENG. The beads are then washed extensively to remove impurities and the bound short sENG digested with a suitable enzyme or chemically cleaved. The digestion or cleavage method being determined by the size of the projected carboxy -terminal peptide (Thermofisher, SureQuant™ Protein A / G IP-MS Sample Preparation Kit Catalog Numbers A51743).

[0330] Mass spectrometry is the preferred method for C-terminal protein sequencing due to its sensitivity and versatility. The protein is first digested into smaller peptides, typically using enzymes like trypsin. This results in a mixture of peptide fragments. The peptide mixture is ionized using techniques such as electrospray ionization or matrix-assisted laser desorption / ionization. The ionized peptides are then analysed in the mass spectrometer, where their mass-to-charge ratios are determined. Tandem mass spectrometry (MS / MS) techniques are used to fragment specific peptides. This fragmentation generates product ions that can be analyzed to determine the amino acid sequence. Software tools are used to interpret the mass spectra and deduce the amino acid sequence of the peptides. Specialised services are available such as Creative Proteomics (Creative Proteomics.com).

[0331] Based on the experimentally determined carboxy-terminal sequence, immunogens are designed and expressed, as described in Example 1, and used to generate short sENG-specific antibodies, as described in Example 2.

[0332] Example 4: Antibody selection and humanisation

[0333] The VH and VL sequences from murine monoclonal antibody candidates of Example 2 are cloned into IgG expression vectors and expressed at 15mL volume by transient transfection in HEK293 cells. Antibodies are analyses by absorbance at 280nm, molecular size by gel electrophoresis under reducing and non-reducing conditions and size-exclusion chromatography for multimers and fragments. The binding characteristics are re-evaluated, by ELISA to show binding to the target protein is retained at high affinity, and by FACS to show that there is little or no residual binding to membrane-spanning endoglin.

[0334] Individual antibodies are assessed for developability by thermal stability, using differential scanning calorimetry, for non-specific binding against baculovirus particles, for hydrophobicity by hydrophobic interaction chromatography and for self-interaction using affinity-capture selfinteraction methodology. The most suitable antibody is humanised in silico by CDR grafting using a ‘best fit’ approach and 16 humanised variants with minimal variation of frameworks from the human germline are designed. DNA sequences encoding the parental variable region, the humanised variable regions and the regions removed to prevent undesirable post-translational modifications. The designed antibodies and the parent antibody are expressed at 15mL volume, purified by affinity chromatography and analysed by absorbance, gel electrophoresis and size-exclusion chromatography. Binding characteristics are assessed by surface plasmon resonance and the antibodies ranked in terms of decreasing dissociation constant.

[0335] The DNA sequences of the top three variants are then modified to include the following Fc modifications according to the EU numbering system: position 234 is substituted with phenylalanine, position 235 is substituted with glutamic acid and position 331 is substituted with serine and positions 253, 310 and 435 are substituted with alanine. The antibodies are again expressed in HEK293 cells, assessed for absorbance, gel electrophoresis and size-exclusion chromatography and fully characterised, in comparison with the parent antibody, in terms of binding characteristics by SPR and for intact mass following deglycosylation. Developability assessments are also repeated.

[0336] One or more of the fully humanised, Fc modified, short sENG-specific antibodies are selected for pharmacological characterisation and full clinical development according to the invention.

[0337] Example 5. Antibody expression and purification.

[0338] Antibody production by transient expression in mammalian cells

[0339] Expression of fully assembled and functional antibodies is achieved by transfection of mammalian cells using an equal mixture of plasmids carrying the desired heavy and light chain DNA sequences respectively. Plasmids for transfection are purified from cultures of E.coli using caesium chloride gradients or anion exchange chromatography following cell lysis. Anion exchange chromatography can be conducted using PureLink from Invitrogen (ThermoFisher Scientific) following the manufacturer’s instructions. Cells such as HEK293 or CHO are grown to high density is a suitable medium and then transfected with suitably prepared DNA combined with lipofectamine or other suitable agent. Cells are cultivated from 24 to 120 hours or longer and then removed by centrifugation or filtration allowing the secreted soluble antibody to be isolated for further purification. EpiCHO-S cells (Thermofisher Scientific) transfected under suitable conditions yield lOOmg plus amounts of antibody per liter of culture. Other methods for transient expression of antibodies are widely available for both CHO and HEK293 cells which are the cell types most widely employed.

[0340] EpiCHO-S stock cells are thawed and grown in suspension in shake flasks, or bioreactor, and diluted to a density of 6 106viable cells / mL in a growth media suitable for transfection. Prior to transfection a suitable quantity of each purified plasmid, containing light and heavy chain DNA sequences, is mixed with transfection agent Epifectamine and introduced to the cell culture at between 0.5 to l.Opg / mL. After 8 to 14 days cells are removed by centrifugation and the supernatant harvested and filtered to remove remaining particulates. Supernatants are further purified immediately or frozen for storage until use. Production of antibodies by transient transfection is widely practiced and there are many known variations of this procedure (Vazquez- Lombardi, R., et al, Transient expression of human antibodies in mammalian cells; Nature Protocols; 2018, 13: 99-117).

[0341] Antibody purification

[0342] Antibodies are purified from cell culture supernatant under controlled conditions to minimise endotoxin levels by affinity chromatography and preparative size exclusion chromatography (SEC). Chromatography is performed on a suitable system such as the Akta pure protein purification system (Cytiva Lifesciences: www. cytivalifesciences. com) with elution of protein measured by optical density at 280nm. Antibodies with a natural (wt) heavy chain sequence are purified by affinity chromatography on protein A (MabSelect SuRe; Cytiva catalogue number 17543801). Antibodies with modifications to the FcRn binding site are purified by affinity chromatography on protein L (Capto L; Cytiva catalogue number 17547802). Briefly sterile (0.2pm filtered) cell culture supernatant containing antibodies with natural heavy chain sequences are applied to a MabSelect SuRe column previously equilibrated with 20mM sodium phosphate, pH 7.2, washed with 35mM sodium phosphate, pH 7.2 containing 500mM sodium chloride to remove impurities, equilibrated with 20mM sodium phosphate, pH 7.2, and the antibody eluted by an increasing gradient of 20mM sodium citrate, pH 3.6. The eluted antibody solution is adjusted to pH 7.2 with 2M Tris, pH 9.0, prior to storage at 2-8°C or -80°C . A similar procedure is used to purify antibodies on a Capto L column except that the column is equilibrated with 20mM sodium phosphate, pH 7.2, containing 150mM sodium chloride and elution is with 0.1M sodium citrate pH 2.0 - 3.5.

[0343] Size exclusion chromatography for further purification is performed on a HiPrep 26 / 60 Sephacryl S200 HR column (Cytiva catalogue number 17119501) or similar. Antibody is loaded onto the column previously equilibrated 50mM sodium phosphate, pH7.2, containing 150mM sodium chloride and the same buffer used for isocratic elution.

[0344] The purity of antibodies is determined by gel electrophoresis in the presence of SDS and under reducing and non-reducing conditions. The content of aggregation and fragments is measured by analytical SEC (Superdex 200 Increase 3.2 / 300 column; Cytiva catalogue number 28990946). Endotoxin is measured using Endosafe (Charles River; criver.com).

[0345] Example 6: Antibody binding characteristics

[0346] By way of example of an approach to antibody binding, the antibody MOm601 / 611 / 621, with the parent heavy chain sequence, is compared to the antibody MOm603 / 613 / 623, with the Fc heavy chain substitutions, I253A+H310A+H435A / L234F+L235E+P331S, which is designed to show much reduced or undetectable binding the FcyRIIb, FcyRIIIa and FcRn.

[0347] Surface plasmon residence (SPR) is commonly used to measure binding affinities between proteins including the binding of antibody Fc regions to ligands and receptors. SPR measures the change in refractive index caused by mass differences due to the binding, or unbinding, of a protein to a gold coated sensor. The BIAcore T200 (Cytivia) is widely used for measuring antibody binding interactions: real-time increases and decreases in mass, reported as resonance units (RU), are used to measure the association (ka) and dissociation (ka) rate constants of binding and determine the equilibrium constant KD. Multicycle kinetics analysis was performed using a Biacore T200 instrument running Biacore T200 Evaluation Software V3.0.1 in order to assess the binding of antibodies to Fc receptors.

[0348] Binding to FcRn: Antibodies MOm601 / 611 / 621 and MOm603 / 613 / 623 are coupled to the dextran matrix of a CM5 sensor chip (Cytiva, catalogue number 29104988) using an Amine Coupling Kit (Cytiva, catalogue number BRI 00050) at a surface density of approximately 1000 RU and excess reactive esters quenched by inj ection of 70pl of 1.0M ethanolamine hydrochloride, pH 8.5. Human FcRn (Sino Biologicals, catalogue number CT009-H08H) is serially diluted (2.86pMto 6nM) into 25mM PBS, pH 6.0 containing 0.05% Tween 20 and used in equilibrium binding experiments. FcRn-Fc binding is maximal around pH 6.0 and greatly reduces at pH7.4. All measurements are performed at 25°C and with a flow rate of 5pl / min; data are collected for 50 min and three 1 minute pulses of PBS, pH 7.4 containing 0.05% Tween 20 are used to regenerate the surface. Background binding is determined by flowing human FcRn at a concentration of 1.0 pM in 25 mM PBS, pH 7.4 containing 0.05% Tween 20 over a blank uncoated sensor chip.

[0349] Binding to FcyRIIb: Antibodies are coupled to the dextran matrix of a CM5 sensor chip at a surface density of approximately 1000 RU using the same methodology as for FcRn. Human FcyRIIb (Sino Biologicals, catalogue number 10259-H08H) is serially diluted from 2.86pM to 6nM in buffer containing 20mM HEPES, pH 7.4, 150mM NaCl, 3mM EDTA and 0.05% Tween 20 and used at a flow rate of 5 pl / min at 25°C for equilibrium binding experiments. Data are collected for 50 min, and one 30s pulse of 5mM HC1 is used to regenerate the surfaces. Background binding is determined by flowing human FcyRIIb at a concentration of 1.0 pM in 25 mM PBS, pH 7.4 containing 0.05% Tween 20 over a blank uncoated sensor chip.

[0350] Binding to FcyRIIIa: Antibodies are coupled to the dextran matrix of a CM5 sensor chip at a surface density of approximately 8000 RU, to compensate for the lower binding affinity of FcyRIIIa compared to FcyRIIb, using the same methodology as for FcyRIIb. Human FcyRIIIa (Sino Biologicals, catalogue number 10389-H08H1) is serially diluted from 16 pM to 31.3 nM in buffer containing 20mM HEPES, pH 7.4, 150mM NaCl, 3mM EDTA and 0.05% Tween 20 and used at a flow rate of 5 pl / min at 25°C for equilibrium binding experiments. Data are collected for 50 min, and one 30s pulse of 5mM HC1 is used to regenerate the surfaces. Background binding is determined by flowing human FcyRIIIa at a concentration of 1.0 pM in 25 mM PBS, pH 7.4 containing 0.05% Tween 20 over a blank uncoated sensor chip.

[0351] Example 7: Fluorescence labelling of antibodies

[0352] Fluorescent labels derivatised with N-hydroxysuccinimide reactive groups can be conveniently attached to exposed amine groups on the surface of antibodies. A dye to antibody molar ration of around four is normally ample to allow fluorescence imaging without interfering with the functionality of the antibody. Dyes which are effective at longer wavelengths are preferred, for example Alexa Fluor 750 (Thermofisher Scientific, Catalogue number MP30045), Chromeo 546 or Chromeo 642 (both from Activemotive.com, Catologue numbers 15191 and 15311 respectively), iFluor 750 (AAT Bioquest, aatbio.com, Catalogue number 1037) and similar dyes (fluorofinder, com).

[0353] By way of example of an approach to labelling of antibodies the MOm601 / 611 / 621 and MOm603 / 613 / 623 antibodies are labelled with Alexa Fluor 750, a fluorescent dye with near- infra red excitation (749nm) and emission (775) wavelengths, according to the protocol MP30045 available from ThermoFisher (SAIVI™ Rapid Antibody Labeling Kits).

[0354] Three mg of each antibody is labelled based on N-hydroxysuccinimide chemistry. Briefly, the method involves diluting the antibody into an alkaline solution of sodium bicarbonate, transfer of the antibody solution to a tube containing lyophilised chemically reactive dye which dissolved on contact with the antibody solution, incubation to allow the dye-protein labelling reaction and removal of excess dye by gel filtration. The reaction conditions are optimised to promote a two to one ratio of dye to protein and the degree of labelling is measured by comparing the absorbances at 280nm and 752nm after corrections for effects of the dye on the 280nm absorbance and the dilution. The labelled proteins were stored at 2-8°C in the dark and are stable for at least one month.

[0355] Analysis of labelled antibodies

[0356] Size-exclusion high performance liquid chromatography is performed on each of the labelled antibodies to determine the degree of aggregation, degradation and purity following the labelling reaction and purification procedure and compared to unmodified MOm601 / 611 / 621. Isocratic chromatography carried out using a Super dex 200 Increase 3.2 / 300 column or equivalent, in a mobile phase containing 20 mM sodium phosphate, pH 7.4, and 400 mM sodium chloride. The proteins were detected by UV absorbance at 280 nm and the retention time and percent total area of the main peak reported. The ability of labelled MOm601 / 611 / 621 to bind FcRn is confirmed by Biocore binding analysis as described in Example 6 in order to demonstrate no impact of the label at low molar ratios.

[0357] Example 8: Maternofetal transfer with fluorescent antibodies.

[0358] By way of example of an approach assessing maternofetal transfer, the inhibition of maternofetal transfer by the introduction of mutations to greatly reduce or abolish receptor binding affinities is demonstrated by comparing the maternofetal transfer of labelled MOm601 / 611 / 621, without modifications to receptor binding, with that of labelled MOm603 / 613 / 623 which includes the modifications I253A+H310A+H435A / L234F+L235E+P331S. Transfer is measured by direct fluorescence imaging of isolated fetuses in a BABL / c mouse model. Images in the near-infra-red are made using the IVIS 200 (Caliper, Perkin Elmer) but any instrument of equivalent capabilities can be used (Photon Imager (Biospace Lab), UVP iBox Studio (Analytik Jena), Pearl Trilogy (LI- COR Biosciences), NightOWL II LB 983 (Berthold Technologies), Lago, Ami HT, and Kino (Spectral Instruments Imaging), and Visque InVivo ART and InVivo Smart-LF (Vieworks)).

[0359] BALB / c male and female mice were housed under SPF conditions with appropriate regard for welfare and following all local regulations. Males were mated at 18 weeks and females at 16 weeks. The morning after mating pregnant females were identified by the presence of a viscous vaginal plug. Such females were designated as gestational day 0.5 (DO.5) and dosing was performed on DI 6.5. Pregnant mice were assigned to three groups of three based on body weight. The first group was administered phosphate-buffered saline (PBS) only, the second group received 30mg / kg of AF647-MOm601 / 611 / 621 and the third 30mg / kg of AF647-MOm603 / 613 / 623 On the day of necropsy, animals are euthanized by carbon dioxide inhalation and dissected to remove the uterus with conceptuses. Embryos are carefully separated from extra-embryonic structures and membranes. Embryos are imaged using an IVIS 200 instrument following user instructions with the settings: epi-fluorescence, excitation / emission filters 745 / 800 nm, field of view C or D, medium binning. To determine the relative amount of fluorescent signal in embryos from animals administered labelled MOm601 / 611 / 621 or labelled MOm603 / 613 / 623, embryos are imaged next to embryos from phosphate-buffered saline (PBS)-dosed mice of the same gestational age used as negative controls. The fluorescence fold change for labelled MOm601 / 611 / 621 or labelled MOm603 / 613 / 623 over the control is calculated from the average fluorescence efficiency across three fetuses.

[0360] A pilot study is conducted to confirm the methodology. A Img / kg dose of labelled MOm601 / 611 / 621is administered intravenously to one of two pregnant age-matched D16.5mice with PBS as a control in the second animal. After 24 hours the animals are euthanized and the fetuses dissected away from the placentas and surrounding tissue prior to imaging. Three fetuses from each mouse are subject to fluorescence imaging.

[0361] In a second study the dose dependent transfer of labelled MOm601 / 611 / 621 is determined. A dose ranging study is conducted to establish the optimal dose for comparing transfer between labelled MOm601 / 611 / 621 and PBS control. Pregnant mice are dosed with Img / kg, 0.3mg / kg, O.lmg / kg and 0.03mg / kg of labelled MOm601 / 611 / 621 and compared with a PBS injected control mouse. The average signal from three fetuses per mouse per dose are compared to give the fold-difference over control.

[0362] Expected result: The fold-increase over control was approximately linear with dose for the three highest doses. However the signal for the 0.03mg / kg dose was not significantly different from the control.

[0363] A third study is made to compare maternofetal transfer between labelled MOm601 / 611 / 621 and labelled MOm603 / 613 / 623 to examine the effect of Fc modifications. D16.5 pregnant mice are dosed at 0.3mg / kg with labelled MOm601 / 61 l / 621or labelled MOm603 / 613 / 623 and compared to a PBS control. The degree of inhibition of transfer is measured by comparing the average signal from three fetuses each from the MOm601 / 611 / 621 and MOm603 / 613 / 623 animals corrected for the PBS control.

[0364] Expected result: The fold-difference over control signal for fetuses from the MOm603 / 613 / 623- treated rat mouse less than 5% compared to the fold-difference over control for fetuses from the MOm601 / 611 / 621-treated mouse.

[0365] Example 9: Maternofetal transfer measured by enzyme-linked immunoassay (ELISA) By way of an example of measurement of maternofetal transfer, an ELISA protocol used to quantify concentrations of eg MOm601 / 611 / 621 and MOm603 / 613 / 623 is designed to bind to the Fab region independent of any modifications to the Fc region. The ELISA includes the following steps: coating the 96- well plate with capture antibody; blocking the non-specific binding sites on the plate; adding samples and standards to the plate; adding detection antibody to the plate, and adding the substrate. Between each step, plates are washed three times with PBS Tween (0.05% Tween-20 in PBS with no pH adjustment), followed by three washes with distilled water. Briefly, Nunc MicroWell 96 well plates (Thermofisher Scientific) are coated with lOOpl / well goat antihuman IgG- F(ab’)2 antibody (Bethyl Laboratories Inc. catalogue number A80-249A) at a concentration of 5 pg / mL in 20mM disodium hydrogen phosphate (no pH adjustment) and incubated at 4°C overnight. Plates are blocked with 150pl / well of blocking solution at room temperature for Ih on a plate shaker. One hundred microliters per well of samples and standards are loaded in triplicates and incubated for 2 h at room temperature on a plate shaker. One hundred microliters per well of the 1.4 ng / mL of goat anti-human IgG-F(ab')2 conjugated with alkaline phosphatase (Bethyl Laboratories Inc. catalogue number A80-249AP) in washing buffer is used as the secondary antibody and incubated at room temperature for Ih. One hundred microliters per well of p-nitrophenyl phosphate solution (Img / mL in diethanolamine substrate buffer) was used as the chromogenic substrate. The absorbance at 405nm was measured after 45 minutes in a standard plate reader and concentrations of MOm601 / 611 / 621 and MOm603 / 613 / 623 antibodies are calculated from a standard curve.

[0366] The half-lives of MOm601 / 611 / 621 and MOm603 / 613 / 623 are measured in a suitable mouse strain, for example, BALB / c. All mice are injected once intravenously via the tail vein with up to 200pl per animal with the dose ranging from 50 to 500pg of antibody. Mice are allocated to two groups with five animals each. Blood samples are taken from group 1 at 1, 24 and 96 hours and from group 2 at 7, 48 and 168 hours after dosing. Blood was collected via the retrobulbar venous plexus from each animal for the determination of the compound levels in serum. Serum samples were obtained from blood after coagulation for one hour at room temperature by centrifugation (10,000g for 3 minutes at 4°C) for 3 min. Serum samples were frozen directly after centrifugation and stored frozen at -80°C until analysis. Samples are measured for the concentration of antibody using the ELISA targeting the human Fab region as described. PK parameters are calculated using the WinNonLin software package or similar (https : / / www. certara. com / software / phoenix- winnonlin / ) .

[0367] Maternofetal transfer for MOm601 / 611 / 621 and MOm603 / 613 / 623 antibodies is compared in pregnant mice. BALB / c male and female mice were housed under SPF conditions with appropriate regard for welfare and following all local regulations. Males were mated at 18 weeks and females at 16 weeks. The morning after mating pregnant females were identified by the presence of a viscous vaginal plug. Such females were designated as gestational day 0.5 (DO.5) and dosing was performed on DI 6.5. Three groups of eight late term pregnant mice, one day prior to delivery, are injected intravenously via the tail vein with up to 200pl of a solution containing MOm601 / 611 / 621 or MOm603 / 613 / 623 antibodies at a dose of 1-2 mg per animal. A further group of four pregnant mice is mock injected to serve as controls. After 24 hours, the mice and pups are euthanised. Adult mice are exsanguinated and serum samples obtained from blood, after coagulation for one hour at room temperature, by centrifugation (10,000g for 3 minutes at 4°C) before storage at -80°C until analysis. Foetal tissue lysates are prepared by homogenization in ice-cold lysis buffer (50 mM Tris, 150mM NaCl, 1% Triton X-100, 1% Y-30, pH 7.4) using a gentleMACS Dissociator (Miltenyi Biotech). Lysates are clarified by centrifugation (10,000g for 10 minutes at 4°C), and supernatants stored at -80°C.

[0368] Concentrations of MOm601 / 611 / 621 and MOm603 / 613 / 623 in serum samples and tissue lysates are assayed for the concentration of human antibody using the ELISA targeting the human Fab region as described. Results are analysed by one-way ANOVA using Prism (Graphpad) with Tukey’s post-hoc analysis and plotted using a standard box and whisker plot with median and 95% confidence intervals indicated.

[0369] Comparative Examples 10-15

[0370] The following examples relate to mutation of the Fc portion of an antibody against VEGFR-1

[0371] In the following Examples 10-15, the antibody with a parent sequence heavy chain (SEQ ID NO: 28) and the light chain (SEQ ID NO: 29) is designated MOm301 and also known as WBP70323_l and BB301. The antibody with the substitutions I253A+H310A+H435A / L234F+L235E+P331S in the heavy chain (SEQ ID NO: 30) and the light chain (SEQ ID NO: 29) is designated MOm303 and also known as WBP70323_2 and BB303.

[0372] Data from the Examples below is shown in the figures as follows:

[0373] Figure 1. Gel electrophoresis of purified antibodies WBP70323 1 (MOm301) and WBP70323 2 (MOm303)

[0374] Figure 2. Fold changes of total fluorescence signal of pregnant mice and foetuses

[0375] Figure 3. Plasma concentrations of BB301 and BB303 in pregnant mice and foetuses 24 hours after dosing.

[0376] Example 10: Production of MOm301 and MOm303 by transient expression in CHO cells. Codon-optimised DNA sequences were synthesized and cloned into expression vectors designed to express approximately equivalent molar quantities of the respective heavy and light chains by transient expression in CHO KI cells. Pilot expressions to confirm the functionality of expression vectors were performed. The vectors were then replicated and purified in sufficient quantities for transient expression in cultures of 2 litres. CH0-K1 host cells were thawed and cultured in BM001H medium (WuXi Bio internal Cat. Number) containing 4 mM Glutamine (J.T. Baker, 2078-06) and 1% HT Supplement (Gibco, 11067-030) in preparation for transfections. Separate cultures were transfected with a mixture of equal masses of the light and heavy chain vectors for WBP70323J (vectors PWX4.1-HC-70323_l and PWX4.1-LC-70323_l) and for WBP70323_2 (PWX4.1-HC-70323_2 and PWX4.1-LC-70323_2). Cells were expanded in BM022H media (WuXi Bio internal Cat. Number) containing 6 mM Glutamine (ITW Reagents Al 420, 1000) and 1% HT Supplement (Gibco, 11067-030) and the same media was used for transfection and antibody production. The feeding media used to support production were FM020a (Hyclone- SH31026.01) and FM020b (Hyclone-SH31027.01). Transient transfections were performed for WBP70323 1 and WBP70323 2 in individual 5L shake flasks by mixing the CHO-K1 host cells with polyethyleneimine (PEI, BIOHUB ) and plasmid DNA. The host cells were seeded at 1.8- 2.0x106cells / mL in BM024H medium 96 hours before transfection. Cells were counted for cell density using a Vi-CELL counter, and diluted with pre-warmed BM022H prior to transfection. The diluted host cells were incubated in a Kuhner shaker (36.5°C, 6% CO2, 150 rpm, 50 mm diameter) before use. Vector DNA, 1.25mg each of the appropriate heavy and light chain vectors for the respective antibodies, was added to the diluted host cells, followed by 12mg of PEI. The transfected cultures were incubated with shaking for 2 hours before the addition of feeding media and continued incubation for 4 days at which time the antibodies were harvested. On the harvest day, cell cultures were clarified by centrifugation at 10,000 x g for 40 mins, followed by sterile filtration through a 0.22 pm filter. WBP70323 1 was captured from the supernatant and purified by protein A chromatography using MabSelect SuRe (Cytiva, 17543803). WBP70323_2 was captured and purified using Capto™ L (Cytiva, 17547802).

[0377] Chromatography was performed using an AKTA Pure Ml 50 system. MabSelect SuRe was packed in a 5.0 cm diameter column with a 7.3 cm bed height with a column volume of 140 ml. Capto™ L was packed in a 5.0 cm diameter column with a 7.7cm bed height with a column volume is 150 ml. All runs were conducted in bind-elute mode and the bound protein was eluted by low pH. Eluated fractions for each molecule were tested for concentration and purity. The collected fractions of affinity-purified WBP70323 1 and, separately, WBP70323 2, pooled fractions were further purified by SEC chromatography using Superdex200 (Cytiva, 17104302). Superdex200 resin was packed in a 5.0 cm diameter column with a 87.6 cm bed height and the packed volume was 1720 mL. The fractions containing the individual purified antibodies were concentrated to about 20mg / mL in 20mM Histidine Acetate, 150mM NaCl, pH 5.5 buffer using 30kDa Amicon Ultra-15 mL Centrifugal Filter Units (Millipore UFC903096) and clarified by sterile filtration through 0.22 pm filters. The antibodies were measured for protein content, endotoxin and analysed by SEC, gel electrophoresis and mass spectrometry. The SDS-PAGE profiles under non-reducing and reducing conditions are shown in Figure 1. The masses for the non-reduced antibodies are consistent with the known masses for intact IgG antibodies as are the masses for the individual heavy and light chains after separation under reducing conditions.

[0378] Example 11: Binding characteristics to VEGFR-1, FcyRIIb, FcyRIIIa and FcRn.

[0379] Surface plasmon residence (SPR) is commonly used to measure binding affinities of antibodies to ligands and Fc receptors. SPR measures the change in refractive index caused by mass differences due to the binding, or unbinding, of a protein to a gold coated sensor. The Biocore™ 8k (Cytivia) is widely used for measuring antibody binding interactions: real-time increases and decreases in mass, reported as resonance units (RU), are used to measure the association (ka) and dissociation (ka) rate constants of binding and determine the equilibrium constant KD. Multicycle kinetics analysis was performed using a Biocore™ instrument running Biocore™ Insight Software in order to measure antibody binding to the ligand, VEGFR-1, and to Fc receptors.

[0380] Binding measurements were conducted to evaluate the binding of BB301 (MOm301, WBP70323 1) and BB303 (MOm303, WBP70323 2) to the target ligand, VEGFR-1, the Fey receptors lib and Illa and FcRn at two different pH values. In parallel a third sample, BB301 modified with the dye Alexa Fluor™ 647 and identified as BB301-AF647, was analysed. This analysis was performed to investigate if the dye modification, as described in Example 3, had any effect on either the binding to the target ligand, VEGFR-1 , the Fey receptors lib or Illa or the FcRn receptor compared to the unmodified BB301 antibody.

[0381] Binding to VEGFR-1. Activator solution was prepared by mixing 400mM l-ethyl-3-(3- dimethylaminopropyl) carbodiimide (EDC) and lOOmM N-Hydroxy Succinimide (NHS) immediately prior to injection and activation of a CM5 sensor chip at a flow rate of I OpL / min for 420s. VEGFR1 (H.pro.1 His: Sinobiologics, 10136-H08H1) at a concentration of 0.8pg / mL in lOmM NaAc (pH 5.0) was then injected to flow cell 2 (Fc2) for 60s at a flow rate of lOpL / min. The reference channel Fcl was blocked and not exposed. The chip was deactivated by IM ethanolamine-HCl for 420s at a flow rate of lOpL / min. Six concentrations (0.625, 1.25, 2.5, 5, 10, 20nM) of the analytes BB301, BB303 or BB301-AF647 in running buffer (l xHBS-EP+; 0.1 M HEPES, 1.5 M NaCl, 0.03 M ED TA and 0.5% v / v Surfactant P20; Cytiva BRI 00669) were injected at a flow rate of 30pL / min for an association phase of 240s followed by a dissociation phase of 3600s. The chip was regenerated by the injection of lOmM glycine (pH 1.5) buffer following each dissociation phase.

[0382] The sensorgrams for the reference channel and buffer channels were subtracted from the test sensorgrams and experimental data fitted to a 1:1 binding model. A molecular weight of 146,508 Da was used to calculate the molar concentration of the analytes BB301 and BB301-AF647. A molecular weight of 146,239 Da was used to calculate the molar concentration of the analyte BB303.

[0383] Table 1. Affinity of BB301, BB303 and BB301-AF647 for human VEGFR1

[0384] The dissociation constants for BB301 andBB303 were 1.64x10'1'M and 1 .52x 1 O'" M respectively. The results confirmed that the amino acid substitutions introduced into the Fc region of BB303 have no effect on the binding affinity for VEGFR-1. The dissociation constant for BB301-AF647 is 1.93xlO-11M which is not different from BB301 within the variation of the method. The result confirms that the modification of BB301 with Alexa Fluor™ 647 has no effect on VEGFR-1 binding.

[0385] Binding to Fey receptor lib. The CM5 sensor chip was activated for 420s with activator solution at a flow rate of lOpL / min. Anti-his tag antibody (THE™, Genescript, A00186-100), at a concentration of 30pg / mL in lOmM NaAc pH 4.5, was then injected at a flow rate of 30pL / min for 400s. The chip was deactivated with IM ethanolamine-HCl (Cytiva) at a flow rate of I OpL / min for 420s. His-tagged FcyRIIb (AcrobioSystems, CDB-H5228) at a concentration of 0.7pg / mL in running buffer (l xHBS-EP+), was injected to Fc2 at a flow rate of 1 OpL / min for 30s. Eight concentrations (160, 320, 640, 1280, 2560, 5120, 10240, 20480 nM) of analyte BB301, BB303 or BB301-AF647 in running buffer were injected at a flow rate of 30pL / min during an association phase of 60s, followed by 90s dissociation phase. Glycine (lOmM at pH 1.5) regeneration buffer was injected to the flow cell following every dissociation phase.

[0386] The sensorgrams for reference channel and buffer channel were subtracted from the test sensorgrams. The experimental data were fitted by steady state affinity model. A molecular weight of 146,508 Da was used to calculate the molar concentration of analytes BB301 and BB301- AF647. A molecular weight of 146,239 Da was used to calculate the molar concentration of analyte BB303.

[0387] Table 2. Affinity of BB301, BB303 and BB301-AF647 for FcyRIIb

[0388] The dissociation constants for BB301 and BB303 were 4.1xlO'6M and 1.17xl0'5M respectively. The results demonstrate that the amino acid substitutions introduced into the Fc region of BB303 have reduced the dissociation constant, which is a measure of affinity, by three-fold compared to the unmodified antibody. The dissociation constant for BB301-AF647 is 4.28x10'6M which is highly similar to BB301, within the variation of the method. The result confirms that the modification of BB301 with Alexa Fluor™ 647 has no effect on Fey receptor lib binding.

[0389] Binding to FcyRIIIa (V176)

[0390] The CM5 sensor chip was activated for 420s with activator solution at a flow rate of lOpL / min. THE™ anti-his tag antibody, at 30pg / mL in 10 mM NaAc (pH 4.5), was then injected for 400s at a flow rate of 30pL / min. The chip was deactivated by IM ethanolamine-HCl (Cytiva) at a flow rate of lOpL / min for 420s. His-tagged FcyRIIIa (AcrobioSystems, CD8-H52H4), 0.5pg / mL in running buffer (l xHBS-EP+), was injected to Fc2 at a flow rate of lOpL / min for 30s. Individual injections of BB301 and BB301-AF647 at concentrations of 5, 10, 20, 40, 80, 160, 320 and 640 nM and BB303 at concentrations of 80, 160, 320, 640, 1280, 2560, 5120, 10240 nM in running buffer were made at a flow rate of 30pL / min with an association phase of 300s, followed by 300s dissociation. Glycine (1 OmM at pH 1.5) regeneration buffer was injected to the flow cell following injection. .

[0391] Table 3. Affinity of BB301, BB303 and BB301-AF647 to FcyRIIIa (V176)

[0392] The dissociation constants for BB301 and BB303 are 9.74xlO'8M and 3.9xlO'6M respectively. The results demonstrate that the amino acid substitutions introduced into the Fc region of BB303 have reduced the dissociation constant, which is a measure of the affinity, by forty-fold compared to the unmodified antibody. The dissociation constant for BB301-AF647 is 9.86xlO'8M which is highly similar to BB301, within the variation of the method. The result confirms that the modification of BB301 with Alexa Fluor™ 647 has no effect on Fey receptor Illa binding.

[0393] Binding to human FcRn at pH 6.0 and pH 7.4

[0394] In preparation, human FcRn (AcrobioSystems, FCM-H5286) was buffer-exchanged into pH 6.0 phosphate-buffered saline Tween (PBST pH6.0; 50 mM Na2HPO4 / NaH2PO4, 150 mM NaCl, 0.05% Tween-20, pH 6.0) or pH 7.4 PBST (50 mM Na2HPO4 / NaH2PO4, 150 mM NaCl, 0.05% Tween-20, pH 7.4) running buffer using a desalting column (Zeba Spin Desalting Columns, 7K MWCO, 0.5 mL; Thermofisher, Pierce-89882). The concentrations were determined using a NanoDrop 2000 spectrophotometer.

[0395] The sensor chip activator was prepared by mixing 400 mM EDC and 100 mM NHS immediately prior to injection. CM5 sensor chips were activated for 420s at a flow rate of lOpL / min with the mixture. In separate experiments using dedicated chips, BB301, BB303 or BB301-AF647 at a concentration of lOpg / mL in lOmM NaAc (pH 5.5), were injected to Fc2 for 60s at a flow rate of lOpL / min. Chips were deactivated by IM ethanolamine-HCl for 420s at a flow rate of lOpL / min. In individual experiments the binding characteristics at both pH6.0 and pH7.4 were analyzed for BB301, BB303 or BB301-AF647. Eight concentrations of human FcRn analyte (46.9, 93.7, 187.5, 375, 750, 1500, 3000, 6000nM) in running buffer (PBST, pH 6.0 or 7.4) were injected to Fcl and Fc2 at a flow rate of 30pL / min for an association phase of 60s, followed by 90s dissociation for each pH and for each antibody. Regeneration buffer, PBS (50 mM Na2HPO4 / NaH2PO4, 150 mM NaCl, pH 7.4), was injected to flow cells following every dissociation phase.

[0396] The sensorgrams for the reference channel and buffer channels were subtracted from the test sensorgrams. The experimental data were fitted by steady state affinity model. A molecular weight of 45 kDa was used to calculate the molar concentration of human FcRn.

[0397] Table 4 Affinity of BB301, BB303 and BB301-AF647 to human FcRn

[0398] The dissociation constants for BB301 at pH 6.0 was 2.06x10'6M whereas the binding of BB303 was not detectable. The results demonstrate that the amino acid substitutions introduced into the Fc region of BB303 have greatly diminished binding to the FcRn receptor. Binding to FcRn for both BB301 and BB303 was not detectable at pH 7.4.

[0399] At pH 6.0 the dissociation constant for BB301-AF647 is 1.66xlO'6M which is highly similar to BB301, within the variation of the method. At pH 7.4 binding for BB301-AF647 is also not detectable.

[0400] Example 12: Fluorescent labelling of antibodies

[0401] BB301 stock solution containing 16 mg protein was diluted and distributed between three Amicon Ultra-0.5ml units, concentrated by centrifugation, recovered by centrifugation of the inverted units, pooled and made up to a final volume of 450 pL with IX borate buffer. Three further rounds of centrifugation were performed to replace the original buffer and the final concentrate was diluted to 8mL with IX borate buffer. For labelling, forty microlitres of Alexa Fluor™ 647 NHS Ester was added, mixed and incubated for two hours at room temperature. The free dye was removed by dialysis, the solution diluted and the concentrations of antibody and dye measured using a Nanodrop spectrophotometer (Thermofisher). The protein concentration for AF647-BB301, measured at 280nm using an extinction coefficient of 220762 cm’1M’1, was 2.04 mg / mL (13.9 pM) and the concentration of AF647, measured at 650 nm using an extinction coefficient of 239000 cm M , was 32.2 pM. The final yield of AF647-BB301 was 14.0mg in a volume of 6.9 mL and a ratio of dye-to-protein of 2.3 to 1.

[0402] BB303 was modified by the same method adapted to accommodate the initial concentration of the antibody. The protein concentration, after modification, dialysis and dilution for AF647-BB303, measured at 280 nm using an extinction coefficient of 221215 cm4M4, was 2.15mg / mL (14.7pM) and the concentration of AF647, measured at 650 nm using an extinction coefficient of 239,000 cm4M4, was 33.1pM. The final yield of AF647-BB303 was 14.6mg in a volume of 6.8 mL and a ratio of dye-to-protein of 2.3 to 1 mol / mol. Labelled antibodies were stored at 2-8°C in the dark and are stable for at least one month under these conditions.

[0403] In Example2, SPR analysis of AF647-BB301 demonstrates that the dye-modified antibody has the same binding characteristics for VEGFR-1, Fcyllb, Fcyllla and FcRn as the unmodified BB301 antibody. The labelled antibodies AF647-BB301 and AF647-BB303 have the same degree of modification, in terms of mols of dye per mol of antibody, which means that AF647-BB303 is expected to have the same binding characteristics as unmodified BB303.

[0404] Example 13: Maternofetal transfer with fluorescent-labelled antibodies. The inhibition of maternofetal transfer by the introduction of mutations to greatly reduce or abolish receptor binding affinities was demonstrated by comparing the maternofetal transfer of labelled MOm301 (AF647-BB301), without modifications to receptor binding, with that of labelled MOm303 (AF647-BB303) which includes the modifications I253A+H310A+H435A / L234F+L235E+P331 S.

[0405] BALB / c male and female mice were housed under SPF conditions with appropriate regard for welfare and following all local regulations. Males were mated at 18 weeks and females at 16 weeks. The morning after mating pregnant females were identified by the presence of a viscous vaginal plug. Such females were designated as gestational day 0.5 (DO.5) and dosing was performed on DI 6.5. Pregnant mice were assigned to three groups of three based on body weight. The first group was administered phosphate-buffered saline (PBS) only, the second group received 30mg / kg of AF647-BB301 and the third 30mg / kg of AF647-BB303. Twenty-four hours after dosing the mice were anaesthetized with isoflurane and then subject to fluorescence imaging using an IVIS® Spectrum (Revvity, Inc.). Following imaging the pregnant mice were euthanized under anaesthesia and the foetuses dissected away from the placentas and surrounding tissue prior to imaging. Total fluorescence efficiency was averaged across three foetuses for each mouse to control for variation between foetuses. Fluorescence fold-change was calculated compared to the PBS controls. The laser excitation filter was set to 640 nm and emission filter was set to 680 nm.

[0406] The average fold change in fluorescence for pregnant females and foetuses was measured over the PBS control (Figure 2). The females administered AF647-BB301 exhibited a 70.4 fold-increase in fluorescence; females administered AF647-BB303 exhibited a fold-increase of 21.2. The lower fold-increase for AF647-BB303 is consistent with the increase clearance due to impairment of binding to FcRn and is confirmed by the pharmacokinetic analysis of Example 10. The foetuses of the mice administered AF647-BB301 exhibited a 104.3 fold- increase in fluorescence; foetuses of the mice administered AF647-BB303 had only a 1.74 fold-increase which is not statistically different compared to the PBS control.

[0407] In conclusion, a comparison between fluorescently-labelled BB301 (MOm301) and BB303 (MOm303) demonstrates that the amino acid substitutions I253A+H310A+H435A / L234F+L235E+P331S lead to a reduction in materno-fetal transfer of at least 98.3% (100 minus (1.74 divided by 104.3, multiplied by 100)).

[0408] Example 14: Pharmacokinetics of MOm301 and MOm303 in BALB / c mice

[0409] BALB / c female mice were housed under SPF conditions with appropriate concern for welfare and following all local regulations. Female mice between 8-10 weeks old were randomly assigned to four groups of five. Groups 1 and 2 were dosed with lOmg / kg of BB301 (MOm301) and groups 3 and 4 were dosed with lOmg / kg of BB303 (MOm303). At designated timepoints blood was collected by ocular venous puncture. Mice were fully anesthetized with isoflurane prior to collection: whole blood was collected in 1.5 mL disposable anticoagulant tubes, centrifuged at 8000 rpm for 5 minutes at 4°C, and the plasma supernatant collected for analysis by ELISA. The collection timings were: group 1, 1 h, 24 h, 72 h, 168 h; group 2, 6 h, 48 h, 120 h, 168 h; group 3, 1 h, 6 h, 24 h, 72 h and group 4, 3 h, 8 h, 48 h, 96 h.

[0410] The plasma concentrations of antibodies were measured by ELISA. Each sample was tested in duplicate against a standard curve. Briefly, Goat anti-human IgG-F(ab’)2 antibody (Bethyl Laboratories, A80-249A) was coated at 1 pg / mL on 96- well ELISA plates (100 pL per well) at 37°C for 2.5 hours. The plates were then washed once with PBST (300 pL per well) and blocked with 2% BSA (bovine serum albumin, 200 pL per well) at ambient temperature for 2 hours. After washing three times with PBST (300 pL per well), serial dilutions of standards or plasma samples in 2% BSA were added to the plates (100 pL per well) and incubated at ambient temperature for one hour. After washing three times with PBST (300 pL per well), Goat anti-Human Ig Fab-HRP antibody (Southern Biotech, 2085-05) was added to the plates (100 pL per well) at 0.09 pg / mL and incubated at ambient temperature for one hour. After washing three times with PBST (300 pL per well), tetramethyl benzidine substrate was added to the plates for colour development for 8 minutes (100 pL per well) before the reaction was stopped by adding 2 M HC1 (100 pL per well). The absorbance at 450 nm and 540 nm was determined using a microplate spectrophotometer (SpectraMax® M5e). A standard curve was generated based on the standard samples using SoftMax Pro software. Table 5. Pharmacokinetics of BB301 and BB303 in female mice.

[0411] In conclusion, BB301 (MOm301) exhibits a half-life of 380 hours in female BALB / c mice and BB303 (MOm303) shows that the amino acid substitutions

[0412] I253A+H310A+H435A / L234F+L235E+P331S lead to a reduction half-life to 17 hours.

[0413] Example 15: Maternofetal transfer measured by enzyme-linked immunoassay (ELISA)

[0414] The inhibition of maternofetal transfer by the introduction of mutations to greatly reduce or abolish receptor binding affinities was demonstrated by comparing the maternofetal transfer of BB301 (MOm301), without modifications to receptor binding, with that of BB303 (MOm303) which includes the modifications I253A+H310A+H435A / L234F+L235E+P331S.

[0415] BALB / c male and female mice were housed under SPF conditions with appropriate concern for welfare and following all local regulations. Males were mated at 18 weeks and females at 16 weeks. The morning after mating pregnant females were identified by the presence of a viscous vaginal plug. These females were designated as gestational day 0.5 (DO.5) and dosing was performed on DI 6.5. Pregnant mice were assigned to three groups of four based on body weight. The first group was administered 70mg / kg BB301, the second group received 70mg / kg of BB303 and the third phosphate-buffered-saline (PBS) as a control. Analysis of samples for pregnant female and foetuses was performed 24 hours after administration of BB301 and BB303. Pregnant mice were fully anesthetized with isoflurane prior to blood collection from the ocular venous plexus. Blood was collected from foetuses after decapitation and then pooled. Whole blood was collected in 1.5 mL disposable anticoagulant tubes, centrifuged at 8000rpm for 5 minutes at 4°C, and the plasma supernatant collected for analysis by ELISA according to the method described in Example 10.

[0416] Figure 3 shows the plasma levels of BB301 and BB303 in pregnant mice and foetuses. After 24 hours the BB301 plasma levels for the pregnant female was 271 (SD 58.7); the level for the foetus was 127 (SD 6.73); for BB303 the plasma levels for the pregnant female was 97.0 (SD 2.10); the level for the foetus was 0.27 (SD 0.02).

[0417] In conclusion, based on analysis by quantitative ELISA, a comparison between BB301 (MOm301) and BB303 (MOm303) demonstrates that the amino acid substitutions I253A+H310A+H435A / L234F+L235E+P331S lead to a reduction in materno-fetal transfer of at least 99,8% (100 minus (0.27 divided by 127 multiplied by 100)).

[0418] Examples 16 - 19

[0419] In the following Examples 16 -19, the antibody with the mouse variable heavy chain region and human natural sequence heavy chain constant regions, also known as wt constant regions, (SEQ ID NO: 11) combined with the mouse variable light chain region and human natural sequence kappa light chain constant region (SEQ ID NO: 12) is designated MOm601 and also known as WBP71785 1 . The antibody with the humanized variable heavy chain region and human heavy chain constant regions containing the substitutions I253A+H310A+H435A / L234F+L235E+P331S (SEQ ID NO: 21) and the humanized light chain variable region linked to the human kappa light chain constant region (SEQ ID NO: 20) is designated MOm623 and also known as WBP71785_2 .

[0420] Data from the Examples below is shown in the figures as follows:

[0421] Figure 4. Gel electrophoresis of purified antibodies WBP71785 1 (MOm601) and WBP71785 2 (MOm623)

[0422] Figure 5 Plasma concentrations ofWBP71785_l (MOm601) and WBP71785 2 (MOm623) in pregnant mice and foetuses 12 hours after dosing. Example 16. Production of MOm601 and MOm623 by transient expression in CHO cells.

[0423] Codon-optimised DNA sequences were synthesized and cloned into expression vectors designed to express approximately equivalent molar quantities of the respective heavy and light chains by transient expression in CHO KI cells. Pilot expressions to confirm the functionality of expression vectors were performed. The vectors were then replicated and purified in sufficient quantities for transient expression in cultures of 2 litres. CH0-K1 host cells were thawed and cultured in BM001H medium (WuXi Bio internal Cat. Number) containing 4 mM Glutamine (J.T. Baker, 2078-06) and 1% HT Supplement (Gibco, 11067-030) in preparation for transfections. Separate cultures were transfected with a mixture of equal masses of the light and heavy chain vectors for WBP71785_1 (vectors PWX4.1-HC-71785_1 and PWX4.1-LC-71785_1) and for WBP71785_2(PWX4.1-HC-71785_2 and PWX4.1-LC-71785_2). Cells were expanded in BM022H media (WuXi Bio internal Cat. Number) containing 6 mM Glutamine (ITW Reagents A1420,1000) and 1% HT Supplement (Gibco, 11067-030) and the same media was used for transfection and antibody production. The feeding media used to support production were FM020a (Hyclone-SH31026.01) and FM020b (Hyclone-SH31027.01). Transient transfections were performed for WBP71785_land WBP71785 2 in individual 5L shake flasks by mixing the CHO-K1 host cells with polyethyleneimine (PEI, BIOHUB ) and plasmid DNA. The host cells were seeded at 1.8-2.0x106cells / mL in BM024H medium, (WuXi Bio internal Cat. Number, powder made in Thermo Fisher, liquid prepared by WuXi Bio) containing 4 mM Glutamine (ITW Reagents A1420,1000) and 1% HT Supplement (Gibco, 11067-030), 96 hours before transfection . Cells were counted for cell density using a Vi-CELL counter, and diluted with pre-warmed BM022H prior to transfection. The diluted host cells were incubated in a Kuhner shaker (36.5°C, 6% CO2, 150 rpm, 50 mm diameter) before use. Vector DNA, 1.25mg each of the appropriate heavy and light chain vectors for the respective antibodies, was added to the diluted host cells, followed by 12mg of PEI. The transfected cultures were incubated with shaking for 2 hours before the addition of feeding media and continued incubation for 4 days at which time the antibodies were harvested. On the harvest day, cell cultures were clarified by centrifugation at 10,000 x g for 40 mins, followed by sterile filtration through a 0.22 pm filter. WBP71785 1 was captured from the supernatant and purified by protein A chromatography using MabSelect SuRe (Cytiva, 17543803). WBP71785_2 was captured and purified using Capto™ L (Cytiva, 17547802).

[0424] Chromatography was performed using an AKTA Pure Ml 50 system. MabSelect SuRe was packed in a 5.0 cm diameter column with a 7.3 cm bed height with a column volume of 140 ml. Capto™ L was packed in a 5.0 cm diameter column with a 7.7cm bed height with a column volume is 150 ml. All runs were conducted in bind-elute mode and the bound protein was eluted by low pH. Eluted fractions for each molecule were tested for concentration and purity. The collected fractions of affinity-purified WBP71785 1 and, separately, WBP70323 2, pooled fractions were further purified by SEC chromatography using Superdex200 (Cytiva, 17104302). Superdex200 resin was packed in a 5.0 cm diameter column with a 87.6 cm bed height and the packed volume was 1720 mL. The fractions containing the individual purified antibodies were concentrated to about 20mg / mL in 20mM Histidine Acetate, 150mM NaCl, pH 5.5 buffer using 30kDa Amicon Ultra- 15 mL Centrifugal Filter Units (Millipore UFC903096) and clarified by sterile filtration through 0.22 pm filters. The antibodies were measured for protein content, endotoxin and analysed by SEC, gel electrophoresis and mass spectrometry. The SDS-PAGE profiles under non- reducing and reducing conditions are shown in Figure 4. The masses for the non-reduced antibodies are consistent with the known masses for intact IgG antibodies as are the masses for the individual heavy and light chains after separation under reducing conditions.

[0425] Example 17. Binding characteristics to sEndoglin

[0426] Surface plasmon residence (SPR) is commonly used to measure binding affinities of antibodies to their cognate antigen and was therefore used to measure the affinity of MOm601 and MOm623 for soluble Endoglin. SPR measures the change in refractive index caused by mass differences due to the binding, or unbinding, of a protein to a gold coated sensor chip. The Biacore™ 8k (Cytivia) is widely used for measuring antibody binding interactions: real-time increases and decreases in mass, reported as resonance units (RU), are used to measure the association (ka) and dissociation (ka) rate constants which are then used to determine the equilibrium constant KD. Multicycle kinetics analysis was performed using a Biacore™ instrument running Biacore™ Insight Software in order to measure antibody binding to the ligand. Binding measurements were conducted to evaluate the binding of MOm601, (WBP71785 1) and MOm623 (WBP71785 2) to the target ligand, soluble Endoglin.

[0427] Immobilization. The activator was prepared by mixing 400mM EDC (l-Ethyl-3-(3- Dimethylaminopropyl) Carbodiimide) and lOOmM NHS (N-HydroxySuccinimide) immediately prior to injection. The CM5 sensor chip was activated for 420s with the mixture at a flow rate of lOpL / min. Anti-human Fc antibody (30 pg / mL) in 10 mM acetate buffer pH4.5 was then injected to chip for 420s at a flow rate of lOpL / min. The chip was deactivated with IM ethanolamine-HCl at a flow rate of 10 pL / min for 420s.

[0428] Capturing Ligand and Running Analyte. WBP71785_1 (1.1 pg / mL) or WBP71785_2 (1.5 pg / mL) in running buffer (1 xHBS-EP+) was injected to flow cell 2 at a flow rate of lOpL / min for 30s. Nine concentrations (0, 0.781, 1.563, 3.125, 6.25, 12.5, 25, 50, and 100 nM) of the analyte human endoglin / CD105 in running buffer were injected to chip at a flow rate of 30pL / min for an association phase of 240s, followed by a 3600s dissociation phase. Regeneration buffer (10 mM glycine pH 1.5) was injected to flow cells for 30s at a flow rate of 30pL / min for 3 cycles following each dissociation phase.

[0429] Regeneration. The chip was regenerated with 10 mM glycine pH 1.5.

[0430] The sensorgrams for the reference channel and buffer channels were subtracted from the test sensorgrams and experimental data fitted to a 1: 1 binding model. A molecular weight of 125.2 kDa was used to calculate the molar concentration of the analyte human endoglin / CD105 homodimer.

[0431] Table 6 Affinity of BB601 and BB623for human soluble Endoglin

[0432] The dissociation constants for MOm601 and MOm623 are 0.59nM and 1.20nM respectively. The results show that the humanized MOm623 has a two-fold lower affinity for sENG compared to MOm601. This is comparable to the previously reported results comparing the mouse chimeric and the humanized anti-endoglin antibodies (0.53nM and 0.82nM respectively,

[0433] WO2011041441Al).The results confirm that the amino acid substitutions introduced into the Fc region of MOm623 have had no significant impact on the binding affinity for sENG.

[0434] Example 18. Pharmacokinetics of WBP71785 1 (MOm601) and WBP71785 2 (MOm623) in BALB / c mice

[0435] BALB / c female mice were housed under SPF conditions with appropriate concern for welfare and following all local regulations. Female mice between 8-10 weeks old were randomly assigned to four groups of five based on body weight. Groups 1 and 2 were dosed with lOmg / kg of WBP71785 1 and groups 3 and 4 were dosed with lOmg / kg of WBP71785_2. At designated timepoints, blood was collected by ocular venous puncture. Mice were fully anesthetized with isoflurane prior to collection: whole blood was collected in 1.5 mL disposable anticoagulant tubes, centrifuged at 8000 rpm for 5 minutes at 4°C, and the plasma supernatant collected for analysis by ELISA. The collection timings were: group 1, 1 h, 24 h, 72 h, 168 h; group 2, 6 h, 48 h, 120 h, 168 h; group 3, 1 h, 6 h, 24 h, 72 h and group 4, 3 h, 12h, 48 h, 96 h.

[0436] The plasma concentrations of antibodies were measured by ELISA. Each sample was tested in duplicate against a standard curve. Briefly, Goat anti-human IgG-F(ab’)2 antibody (Bethyl Laboratories, A80-249A) was coated at 1 pg / mL on 96-well ELISA plates (100 pL per well) at 37°C for 2.5 hours. The plates were then washed once with PBST (300 pL per well) and blocked with 2% BSA (bovine serum albumin, 200 pL per well) at ambient temperature for 2 hours. After washing three times with PBST (300 pL per well), serial dilutions of standards or plasma samples in 2% BSA were added to the plates (100 pL per well) and incubated at ambient temperature for one hour. After washing three times with PBST (300 pL per well), Goat antiHuman Ig Fab-HRP antibody (Southern Biotech, 2085-05) was added to the plates (100 pL per well) at 0.09 pg / mL and incubated at ambient temperature for one hour. After washing three times with PBST (300 pL per well), tetramethyl benzidine substrate was added to the plates for colour development for 8 minutes (100 pL per well) before the reaction was stopped by adding 2 M HC1 (100 pL per well). The absorbance at 450 nm and 540 nm was determined using a microplate spectrophotometer (SpectraMax® M5e). A standard curve was generated based on the standard samples using SoftMax Pro software (moleculardevices.com). Data are represented as Mean ± SD.

[0437] The plasma concentration of WBP71785 antibodies in mouse was subjected to a noncompartmental pharmacokinetic analysis by using the Phoenix WinNonlin software (version 8.3, Pharsight, Mountain View, CA). The linear / log trapezoidal rule was applied in obtaining the PK parameters.

[0438] Table 7 Pharmacokinetics of WBP71785 1 (M0m601) and WBP71785 2 (MOm623) in BALB / c mice

[0439] In conclusion, WBP71785 1 (M0m601) exhibits a half-life of 130 hours in female BALB / c mice and WBP71785 2 (MOm623) demonstrates that the amino acid substitutions

[0440] I253A+H310A+H435A / L234F+L235E+P331S lead to a reduction in half-life to 4.0 hours.

[0441] Example 19. Maternofetal transfer measured by enzyme-linked immunoassay (ELISA)

[0442] The inhibition of maternofetal transfer by the introduction of mutations in the heavy chain constant region to greatly reduce or abolish receptor binding affinities was demonstrated by comparing the maternofetal transfer of WBP71785 1 (MOm601) without modifications to receptor binding, with that of WBP71785 2 (MOm623) which includes the modifications I253A+H310A+H435A / L234F+L235E+P331 S.

[0443] BALB / c male and female mice were housed under SPF conditions with appropriate concern for welfare and following all local regulations. Males were mated at 18 weeks and females at 16 weeks. The morning after mating pregnant females were identified by the presence of a viscous vaginal plug. These females were designated as gestational day 0.5 (DO.5) and dosing was performed on DI 7. Pregnant mice were assigned to two groups of three based on body weight. The first group was administered 75mg / kg BB301, the second group received 75mg / kg of BB303. Analysis of samples for pregnant female and foetuses was performed 12 hours after administration of WBP71785 1 (MOm601) and WBP71785 2 (MOm623).

[0444] Pregnant mice were fully anesthetized with isoflurane prior to blood collection from the ocular venous plexus. Blood was collected from foetuses after decapitation and then pooled. Whole blood was collected in 1.5 mL disposable anticoagulant tubes, centrifuged at 8000rpm for 5 minutes at 4 °C, and the plasma supernatant collected for analysis by ELISA according to the method described in Example 14.

[0445] Plasma Concentrations of WBP71785 1 and WBP71785 2

[0446] Figure 5 shows the plasma levels of WBP71785 1 (MOm601) and WBP71785_2 (MOm623) in pregnant mice and foetuses. After 12 hours the WBP71785 1 plasma levels for the pregnant female was 240pg / mL (SD 8.1); the level for the foetus was 95.7 pg / mL (SD 11.7); for WBP71785_2 the plasma levels for the pregnant female was 99.7 pg / mL (SD 8.1); the level for the foetus was 0.15 pg / mL or lower (SD not determined).

[0447] In conclusion, based on analysis by quantitative ELISA, a comparison between WBP71785 1 (MOm601) and WBP71785 2 (MOm623) demonstrates that the amino acid substitutions I253A+H310A+H435A / L234F+L235E+P331S lead to a reduction in materno-fetal transfer of at least 99,8% (100 minus (0.15 divided by 95.7 multiplied by 100)).

[0448] Table 8. Description of sequences

[0449] Table 9. List of sequences identified in the Description and Claims. Mutations and substitutions are denoted in bold and underline type.

Claims

Claims1. An isolated binding molecule for use in medicine in a pregnant woman, wherein the binding molecule specifically binds to short soluble endoglin (short sENG).

2. An isolated binding molecule for use in the treatment or prevention of a disorder of pregnancy in a pregnant woman, wherein the binding molecule specifically binds to short soluble endoglin (short sENG).

3. A method of treating a pregnant woman, the method comprising administering an effective amount of an isolated binding molecule, wherein the binding molecule specifically binds to short soluble endoglin (short sENG).

4. An isolated binding molecule for use in medicine in a pregnant woman according to claim 1 , or for use in therapy or prevention of a disorder of pregnancy in a pregnant woman according to claim 2, or a method of treatment of a pregnant woman according to claim 3, wherein the binding molecule comprises an antigen binding domain, such as an antigen-binding domain of a monoclonal antibody or an antigen-binding fragment thereof.

5. An isolated polypeptide for use in medicine in a pregnant woman, or for use in therapy or prevention of a disorder of pregnancy in a pregnant woman, or a method of treatment of a pregnant woman according to claim 4, wherein the binding molecule is a monoclonal antibody, preferably a humanized monoclonal antibody.

6. An isolated binding molecule for use in medicine in a pregnant woman according to claims 1, 4 or 5, or for use in therapy or prevention of a disorder of pregnancy in a pregnant woman according to claims 2, 4 or 5, or a method of treatment of a pregnant woman according to any of claims 3 to 5, wherein the binding molecule comprises a human variant IgGFc domain having a mutation or combination of mutations with respect to the parent sequence which reduce binding of the Fc domain to any FcyR, and a mutation or combination of mutations with respect to the parent sequence which reduce binding of the Fc domain to FcRn, whereby maternofetal transfer is inhibited with respect to the parent sequence by at least 95% or more.

7. An isolated binding molecule for use in medicine in a pregnant woman according to claims 1 or 4 to 6, or for use in therapy or prevention of a disorder of pregnancy in a pregnant woman according to claims 2 or 4 to 6, or a method of treatment of a pregnant woman according to any of claims 3 to 6, wherein the binding molecule comprises a human variant IgG Fc domain comprising amino acid substitutions numbered according to the Eu numbering scheme relative to a human wild-type Fc domain, wherein: a) (i) positions 234 and 235 are each substituted with alanine or(ii) positions 234 and 235 are each substituted with alanine and position 331 is substituted with serine or(iii) position 234 is substituted with phenylalanine, position 235 is substituted with glutamic acid and position 331 is substituted with serine or(iv) position 328 is substituted with arginine and arginine is inserted after position 236; and b) (i) position 253 is substituted with alanine or(ii) position 435 is substituted with alanine or(iii) positions 253, 310 and 435 are substituted with alanine or(iv) position 310 is substituted with alanine and position 435 is substituted with glutamine wherein said polypeptide has reduced binding to at least one Fc gamma receptor (FcyR) and to FcRn, when compared to the unsubstituted polypeptide comprising the parent Fc domain.

8. An isolated binding molecule for use in medicine in a pregnant woman, or for use in therapy of a pregnant woman, or a method of treatment of a pregnant woman according to any of claims 4 to 7, wherein at least one FcyR is selected from FcyRi, FcyRIIa, FcyRIIb, Fcyllla, and FcyRIIIb, preferably Fcyllb and Fcyllla.

9. An isolated binding molecule for use in medicine in a pregnant woman, or for use in therapy of a pregnant woman, or a method of treatment of a pregnant woman according to any of claims 4-8, wherein the IgG Fc domain is selected from the group consisting of human immunoglobulin G class 1 (IgGl) Fc domain, human immunoglobulin G class 2 (IgG2) Fc domain, human immunoglobulin G class 3 (IgG3) Fc domain, and human immunoglobulin G class 4 (IgG4) Fc domain, preferably human immunoglobulin G class 1 (IgGl) Fc domain.

10. An isolated binding molecule for use in medicine in a pregnant woman according to any of claims 1 or 4-9, or for use in therapy of a pregnant woman according to any of claims 2 or 4-9, or a method of treatment of a pregnant woman according to any of claims 3-9, wherein the binding molecule is in the form of a conjugate comprising a variant IgG Fc domain, polypeptide or antibody according to any preceding claim and a therapeutic moiety.

11. A nucleic acid comprising a nucleotide sequence encoding a polypeptide binding molecule as disclosed in any of claims 1-10 for use in therapy of a pregnant woman, for example in the treatment or prevention of a disorder of pregnancy.

12. A vector comprising the nucleic acid of claim 11 for use in therapy of a pregnant woman, for example in the treatment or prevention of a disorder of pregnancy.

13. A host cell comprising the nucleic acid according to claims 11 or 12 for use in therapy of a pregnant woman, for example in the treatment or prevention of a disorder of pregnancy.

14. An isolated binding molecule for use in medicine in a pregnant woman according to any one of claims 1 or 4-9, or for use in therapy of a pregnant woman according to any one of claims 2 or 4-9, or a method of treatment of a pregnant woman according to any one of claim 3-9, or anucleic acid for use according to claim 11, vector for use according to claim 12 or cell for use according to claim 13, wherein the binding molecule is in the form of a pharmaceutical composition which comprises a pharmaceutically acceptable excipient.

15. An isolated binding molecule for use, method of treatment, nucleic acid for use, vector for use or cell for use according to any one of claim 1-14, in the treatment or prevention of a disorder of pregnancy, optionally wherein the disorder or disease is a hypertension-related condition or pre- eclampsia / eclampsia, and / or SGA, and / or HELLP Syndrome.

16. A pharmaceutical composition comprising an antibody that specifically binds to short sENG formulated with pharmaceutically acceptable excipient or carrier.

17. A pharmaceutical composition according to claim 16 for use in in the treatment or prevention of a disorder of pregnancy, optionally wherein the disorder or disease is a hypertension- related condition or pre-eclampsia / eclampsia, and / or SGA, and / or HELLP Syndrome.

18. An isolated binding molecule for use, method of treatment, nucleic acid for use, vector for use, cell for use, composition or composition for use according to any one of claim 1-17 wherein the binding molecule is a polypeptide, such as a monoclonal antibody.

19. An isolated binding molecule for use, method of treatment, nucleic acid for use, vector for use, cell for use, composition or composition for use according to any one of claim 1-18, wherein the binding molecule comprises a binding domain, such as an antibody variable region, that specifically binds to short sENG, optionally where the molecule is a monoclonal antibody.

20. An isolated binding molecule comprising a binding domain that specifically binds to short soluble endoglin (short sENG), or a fragment thereof, optionally wherein the binding domain binds to a C-terminal fragment of short sENG.

21. An isolated binding molecule according to claim 20, wherein the binding molecule is a n antibody, optionally a monoclonal antibody, optionally a human or humanized monoclonal antibody.

22. An isolated binding molecule according to claims 20 or 21, wherein the binding molecule comprises a human variant IgGFc domain having a mutation or combination of mutations with respect to the parent sequence which reduce binding of the Fc domain to any FcyR, and a mutation or combination of mutations with respect to the parent sequence which reduce binding of the Fc domain to FcRn, whereby maternofetal transfer is inhibited with respect to the parent sequence by at least 95% or more.

23. An isolated binding molecule according to claim 22, wherein the binding molecule comprises a human variant IgGFc domain comprising amino acid substitutions numbered according to the Eu numbering scheme relative to a human wild-type Fc domain, wherein: a) (i) positions 234 and 235 are each substituted with alanine or(ii) positions 234 and 235 are each substituted with alanine and position 331 is substituted with serine or(iii) position 234 is substituted with phenylalanine, position 235 is substituted with glutamic acid and position 331 is substituted with serine or(iv) position 328 is substituted with arginine and arginine is inserted after position 236; and b) (i) position 253 is substituted with alanine or(ii) position 435 is substituted with alanine or(iii) positions 253, 310 and 435 are substituted with alanine or(iv) position 310 is substituted with alanine and position 435 is substituted with glutamine wherein said polypeptide has reduced binding to at least one Fc gamma receptor (FcyR) and to FcRn, when compared to the unsubstituted polypeptide comprising the parent Fc domain.24 An isolated binding molecule, isolated binding molecule for use, method of treatment, nucleic acid for use, vector for use, cell for use, composition or composition for use according to any one of claim 1-23, wherein the binding molecule is a bispecific antibody.Ill

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