LTBP complex-specific inhibitors of TGFβ and uses thereof

Abstract

To provide improved TGFβ inhibitors capable of selectively targeting matrix-associated proTGFβ complexes such as LTBP1-proTGFβ1 and LTBP3-proTGFβ1, and also to provide methods of using these inhibitors for inhibiting TGFβ activation and for treating subjects suffering from TGFβ-related disorders, for example fibrotic conditions.SOLUTION: Provided is an isolated antibody that specifically binds human LTBP1-proTGFβ complexes and / or human LTBP3-proTGFβ complexes and does not bind human GARP-proTGFβ complexes, the antibody not binding mature TGFβ1, mature TGFβ2, or mature TGFβ3, the antibody being a fully human or humanized antibody or an antigen-binding fragment thereof, the antibody comprising at least 3 of the 6 specified CDRs.SELECTED DRAWING: None

Description

[Technical Field]

[0001] [Related Applications] This international application claims the benefit of and priority to U.S. Provisional Application No. 62 / 798,927, filed January 30, 2019, the contents of which are expressly incorporated herein by reference in their entirety. [Background technology]

[0002] [background] The transforming growth factor β (TGFβ) superfamily of growth factors participates in multiple signaling cascades that regulate various biological processes, including, but not limited to, cell proliferation inhibition, tissue homeostasis, extracellular matrix (ECM) remodeling, endothelial-mesenchymal transition, cell migration and invasion, and immune modulation / suppression, as well as mesenchymal-epithelial transition. Regarding ECM remodeling, TGFβ signaling can increase fibroblast populations and ECM deposition (e.g., collagen). In the immune system, TGFβ ligands regulate regulatory T cell function and the proliferation and homeostasis of immune progenitor cells. In normal epithelial cells, TGFβ is a potent growth inhibitor and promoter of cell differentiation. However, as tumors develop and progress, they often lose their negative proliferative response to TGFβ. In this context, TGFβ can be a promoter of tumorigenesis due to its ability to stimulate angiogenesis, alter the stromal environment, and induce local and systemic immunosuppression. For these and other reasons, TGFβ has become a therapeutic target for multiple clinical indications. Despite numerous attempts to date by multiple groups, clinical development of TGFβ therapy has been challenging.

[0003] Preclinical observations involving rats and dogs have revealed certain toxicities associated with TGFβ inhibition in vivo. Furthermore, although several TGFβ inhibitors have been developed to date, most clinical programs targeting TGFβ have been discontinued due to side effects or toxicity risks.

[0004] For example, Anderton et al. (Toxicology Pathology, 39:916-24, 2011) reported that a small molecule inhibitor of the TGFβ type I (ALK5) receptor induced cardiac valve lesions characterized by hemorrhage, inflammation, degeneration, and proliferation of valvular interstitial cells in a preclinical animal model. Toxicity was observed in all cardiac valves at all doses tested. Frazier et al. (Toxicology Pathology, 35:284-295, 2007) reported that administration of GW788388, a small molecule inhibitor of the TGFβ type I (ALK5) receptor, induced epiphyseal cartilage dysplasia in rats.

[0005] Stauber et al. (J. Clin. Practice 4:3, 2014) reported that chronic (≥3 months) administration of LY2157299, an inhibitor of TGFβ receptor I kinase being investigated for the treatment of certain cancers, resulted in multiple organ toxicity in rats and dogs, including cardiovascular, gastrointestinal, immune, bone / cartilage, reproductive, and renal systems.

[0006] Fresolimumab (GC1008), a "pan" TGFβ antibody capable of neutralizing all human isoforms of TGFβ, has been reported to induce epithelial hyperplasia of the gingiva, bladder, and nasal turbinate epithelium after multiple doses in cynomolgus macaques (Lonning et al., Current Pharmaceutical Biotechnology 12:2176-89, 2011). Similarly, various skin rashes / lesions, gingival bleeding, and fatigue have been reported in clinical trials after multiple doses of the drug. The most notable adverse reactions to fresolimumab include the induction of cutaneous keratoacanthoma and / or squamous cell carcinoma in human cancer patients (see, for example, Lacouture et al., 2015, Cancer Immunol Immunother, 64:437-46; Stevenson et al., 2013, OncoImmunology, 2:8, e26218; and Lonning et al., 2011). Further evidence from clinical trials suggests that in some cases this antibody may accelerate tumor progression (Stevenson et al., 2013, OncoImmunology, 2:8, e26218).

[0007] Thus, there is a need for new methods and compositions for modulating TGFβ signaling that can be used to effectively and safely treat diseases and disorders in which TGFβ is involved, including cancer, fibrosis, and inflammation.

[0008] As the potentially dangerous side effects associated with broad-spectrum inhibition of TGFβ have become increasingly recognized, several groups have recently turned to identifying inhibitors that target a subset, but not all, of the isoforms while still maintaining sufficient efficacy. For example, WO2016 / 161410 discloses neutralizing antibodies that bind to both TGFβ1 and TGFβ2 (i.e., TGFβ1 / 2 inhibitors). WO2006 / 116002 provides neutralizing antibodies that bind to both TGFβ1 and TGFβ3 (i.e., TGFβ1 / 3 inhibitors), but preferentially bind the former. In addition to traditional monoclonal antibodies, several groups have developed engineered fusion proteins that function as so-called "ligand traps" (see, e.g., WO2018 / 158727, WO2018029367, and WO2018129331), at least some of which may be selective for TGFβ1 / 3. Another class of TGFβ1 / 3 inhibitors includes inhibitors of α-V (αν) integrins, such as antibodies against ανβ6, an integrin known to activate both TGFβ1 and TGFβ3 (i.e., TGFβ1 / 3). Still other groups continue to search for "better" pan-inhibitors (i.e., TGFβ1 / 2 / 3 or pan-inhibitors) that inhibit all three isoforms (see, e.g., WO2018 / 134681).

[0009] However, from an efficacy perspective, conventional wisdom in the field is that it is advantageous to inhibit multiple isoforms of TGFβ to achieve therapeutic benefit, and to accommodate this, toxicity management through “careful dosing regimens” has been suggested as a solution (Brennan et al. (2018) mAbs, 10:1, 1-17).

[0010] More recently, applicants have described isoform-selective TGFβ1 inhibitors that have been shown to be safe and effective in animal models (see, e.g., WO2017 / 156500 and WO2018 / 129329, which are incorporated by reference), supporting the concept that selectively targeting the TGFβ1 isoform, as opposed to broadly antagonizing all TGFβ isoforms, may provide an advantageous approach for achieving efficacy with acceptable toxicity.

[0011] Although the observed safety profile achieved by selectively inhibiting TGFβ1 at doses shown to be effective in vivo is a promising step toward the development of TGFβ1 inhibitors for clinical application, the identification of TGFβ1 inhibitors capable of selectively affecting a predetermined subset of TGFβ1 effects (e.g., TGFβ inhibitors selective for the complex presented by LTBP) has remained elusive. Recently, the applicant has demonstrated that such "LTBP context-specific" inhibitors can be produced using methods previously described by the applicant (see, for example, WO2014 / 074532 and WO2014 / 182676) (WO2019 / 023661, incorporated herein by reference). However, the LTBP-selective TGFβ1 inhibitors described in the aforementioned international publications exhibited moderate affinity and inhibitory activity, along with suboptimal species cross-reactivity. Summary of the Invention [Problem to be solved by the invention]

[0012] The present disclosure provides improved TGFβ inhibitors that are capable of selectively targeting matrix-associated proTGFβ complexes such as LTBP1-proTGFβ1 and LTBP3-proTGFβ1.

[0013] These inhibitors bind to and inhibit proTGFβ presented by LTBP1 and / or LTBP3 with high affinity (at least in the nanomolar range), but do not bind to or inhibit immune cell-associated TGFβ, such as proTGFβ1 presented by GARP and / or LRRC33, or their binding is less than significant (e.g., the affinity for the LTBP complex is at least 50-fold higher than that for the GARP or LRRC33 complex). Thus, these inhibitors can selectively inhibit TGFβ activation in a context-dependent manner, thus selectively binding to and thereby inhibiting the ECM-associated TGFβ signaling axis. In particular, the present disclosure includes selective inhibitors of matrix-associated (e.g., LTBP1- and / or LTBP3-associated) TGFβ activation. In some embodiments, such inhibitors specifically bind to a particular isoform of TGFβ (e.g., proTGFβ1, proTGFβ2, and / or proTGFβ3) associated with LTBP1 and / or LTBP3, thus also providing TGFβ isoform specificity. In certain embodiments, such inhibitors specifically bind to LTBP1 / 3-proTGFβ1. In any embodiment of the invention, such inhibitors do not inhibit TGFβ1 activation associated with immune cell function mediated by GARP and / or LRRC33. Improved antibodies included in the present disclosure have a potency of at least in the nanomolar range (i.e., 1×10 -9 M~10×10 -9 In some embodiments, such antibodies have an affinity for human LTBP1-proTGFβ1 and / or human LTBP3-proTGFβ1 in the nanomolar range (i.e., 1×10 -9 M~10×10 -9 M) also has affinity for murine LTBP1-proTGFβ1 and / or murine LTBP3-proTGFβ1.

[0014] There are at least three rationales for the therapeutic use of TGFβ1 inhibitors that do not target the GARP-proTGFβ1 complex on regulatory T cells:

[0015] First, regulatory T cells play a crucial role in maintaining immune tolerance to self-antigens and preventing autoimmune diseases. Because Tregs generally suppress, attenuate, or downregulate the induction and proliferation of effector T cells, systemic inhibition of this function can lead to overactive or exaggerated immune responses in the host by abolishing the "break" normally provided by Treg cells. Therefore, the approach taken here (e.g., TGFβ1 inhibition without abolishing Treg function) aims to avoid the risk of inducing autoimmunity. Furthermore, patients who already have a tendency to develop hyperactive immune responses or autoimmunity may be particularly at risk of developing or worsening such conditions because normal Treg function is unavailable; therefore, inhibitors that selectively target matrix TGFβ1 may advantageously minimize such risks.

[0016] Second, evidence suggests that altered Th17 / Treg ratios result in a pro-fibrotic Th17 cytokine imbalance, which correlates with the severity of fibrosis, such as liver fibrosis (see, e.g., Shoukry et al. (2017) J Immunol 198(1 Supplement):197.12). We determined that disruption of the GARP arm of TGFβ1 function may directly or indirectly exacerbate fibrotic conditions.

[0017] Third, regulatory T cells are essential for immune homeostasis and the prevention of autoimmunity. It was determined that TGFβ1 blockade, particularly for long-term or chronic administration, would be desirable to avoid potential side effects resulting from disruption of normal Treg function in maintaining immune homeostasis (e.g., reviewed in Richert-Spuhler and Lund (2015) Prog Mol Biol Transl Sci. 136:217-243). This strategy is aimed, at least in part, at maintaining normal immune function, which is necessary, inter alia, for fighting infection.

[0018] To achieve this goal, the inventors of the present disclosure sought to produce isoform-specific, context-selective inhibitors of TGFβ1 that selectively target matrix-associated, but not immune cell-associated, TGFβ1 activation.

[0019] Technical challenges that exist to date include limited ability to distinguish and selectively modulate these subpools of TGFβ1 that exist within various contexts (or "niches") in vivo. [Means for solving the problem]

[0020] In an attempt to address this challenge, the present inventors have identified isoform-specific monoclonal antibodies that bind to the latent TGFβ1 prodomain, lack detectable binding to latent TGFβ2 or TGFβ3, and inhibit integrin-mediated activation of latent TGFβ1 in vitro in a context-dependent manner, as described herein. The discovery and characterization of such antibodies was made possible, at least in part, by the development of a context-dependent, cell-based assay for TGFβ1 activation. During the development and validation of this novel assay, it was shown that, like αVβ6 integrin, αVβ8 can also activate LTBP1-proTGFβ1. Furthermore, it was shown that, like the LTBP1 complex, LTBP3-proTGFβ1 can be activated by αVβ6. The antibodies discovered by screening in these assays defined a class of antibodies that bind to and inhibit TGFβ1 only when presented by LTBP1 or LTBP3. Such LTBP-specific antibodies do not inhibit TGFβ1 in the context of immune-related TGFβ1 presenters GARP and LRRC33. Such antibodies are therapeutic candidates for treating disorders, including fibrotic conditions, and can be administered chronically, avoiding TGFβ-related immune system activation. Methods for selecting context-specific or context-independent TGFβ1 inhibitors for various fibrotic conditions are also provided herein.

[0021] Thus, in one aspect, the present invention provides a method for producing a medicament for the treatment of malaria. D The present invention provides an isoform-specific TGFβ antibody, or antigen-binding fragment thereof, characterized in that it selectively binds to the LTBP1-TGFβ1 complex and / or the LTBP3-TGFβ1 complex at ≦50 nM. D The present invention provides an isoform-specific TGFβ antibody, or antigen-binding fragment thereof, characterized in that it selectively binds to the LTBP1-TGFβ1 complex and / or the LTBP3-TGFβ1 complex at ≦25 nM. D The present invention provides an isoform-specific TGFβ antibody, or antigen-binding fragment thereof, characterized in that it selectively binds to the LTBP1-TGFβ1 complex and / or the LTBP3-TGFβ1 complex at ≦10 nM. In one embodiment, the present invention provides an isolated antibody, or antigen-binding portion thereof, that selectively binds to the LTBP1-proTGFβ1 complex and the LTBP3-proTGFβ1 complex, wherein the antibody, or antigen-binding portion thereof, does not bind to one or more of the following targets: (a) LTBP1 alone; (b) proTGFβ1 alone; (c) GARP-proTGFβ1 complex; and (d) LRRC33-proTGFβ1 complex. In a further embodiment, the present invention provides an isolated antibody, or antigen-binding portion thereof, that selectively binds to the LTBP1-proTGFβ1 complex and the LTBP3-proTGFβ1 complex, wherein the antibody, or antigen-binding portion thereof, does not bind to one or more of the following targets: (a) LTBP1 alone; (b) proTGFβ1 alone; (c) GARP-proTGFβ1 complex; and (d) LRRC33-proTGFβ1 complex. D Provided is an isoform-specific TGFβ antibody, or an antigen-binding fragment thereof, characterized in that it selectively binds to the LTBP1-TGFβ1 complex and / or the LTBP3-TGFβ1 complex at <5 nM.

[0022] In one aspect, the present invention provides an inhibitor of extracellular matrix-associated TGFβ activation that selectively binds to the proTGFβ latent complex presented by LTBP1 / 3. In one embodiment, the inhibitor does not inhibit immune cell-associated TGFβ1 activation, e.g., immune cell-associated TGFβ1 activation resulting from activation of the proTGFβ1 latent complex presented by GARP. In an exemplary embodiment, the inhibitor is an antibody, or an antigen-binding portion thereof.

[0023] In another aspect, the present invention provides TGFβ antibodies, or antigen-binding fragments thereof, characterized in that they selectively bind to the LTBP1-TGFβ complex and / or the LTBP3-TGFβ complex. In some embodiments, the antibodies, or antigen-binding fragments thereof, selectively bind to LTBP1-TGFβ1. In some embodiments, such antibodies bind to both the human and murine counterparts.

[0024] In one aspect, the invention provides an isolated antibody, or antigen-binding portion thereof, that selectively binds to the LTBP1-proTGFβ latent complex and / or the LTBP3-proTGFβ latent complex, thereby modulating the release of mature TGFβ growth factors from the latent complex, wherein the antibody, or antigen-binding portion thereof, does not bind to mature TGFβ1 alone or to the GARP-proTGFβ1 latent complex. In one embodiment, the antibody, or antigen-binding portion thereof, does not bind to the LRRC33-proTGFβ1 latent complex. Alternatively, in one embodiment, the antibody, or antigen-binding portion thereof, binds to the LRRC33-proTGFβ1 latent complex.

[0025] In some embodiments, the antibody, or antigen-binding portion thereof, is specific for the LTBP1-proTGFβ1 latent complex. In other embodiments, the antibody, or antigen-binding portion thereof, is specific for the LTBP3-proTGFβ1 latent complex. In one embodiment, the antibody, or antigen-binding portion thereof, is specific for at least about 10 -8 Dissociation constant of M (K D In one embodiment, the antibody, or antigen-binding portion thereof, binds to the LTBP1-proTGFβ1 complex and / or the LTBP3-proTGFβ1 complex with a K of <50 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). DIn one embodiment, the antibody, or antigen-binding portion thereof, binds to the human LTBP1-proTGFβ1 complex and / or the human LTBP3-proTGFβ1 complex with a K of <10 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D In one embodiment, the antibody, or antigen-binding portion thereof, binds to the human LTBP1-proTGFβ1 complex and / or the human LTBP3-proTGFβ1 complex with a K of <50 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D In one embodiment, the antibody, or antigen-binding portion thereof, binds to murine LTBP1-proTGFβ1 complex and / or murine LTBP3-proTGFβ1 complex with a K of <10 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D It binds to mouse LTBP1-proTGFβ1 complex and / or mouse LTBP3-proTGFβ1 complex.

[0026] The present disclosure further provides antibodies and antigen-binding fragments thereof that selectively bind to the LTBP1-proTGFβ complex and / or the LTBP3-proTGFβ complex and have one or more additional advantageous properties. Indeed, the present inventors have surprisingly found that they can provide antibodies that bind to the human LTBP1-proTGFβ complex and the human LTBP3-proTGFβ complex with high affinity and advantageously slow dissociation rates, that are also cross-reactive with the mouse LTBP1-proTGFβ complex and the mouse LTBP3-proTGFβ complex, and that do not show significant binding to the human GARP-proTGFβ complex (or indeed the human LRRC33-proTGFβ complex).

[0027] Furthermore, the antibodies disclosed herein (including antibodies having one or more, or indeed all, of the aforementioned advantageous properties) exhibit potent inhibition of TGFβ1 signaling in cell-based assays and significantly reduce fibrotic markers and TGFβ signaling in multiple animal models of fibrosis.

[0028] Thus, in some embodiments, the antibody, or antigen-binding fragment thereof, has a K of <5 nM as measured by BLI. D and binds to the human LTBP1-proTGFβ1 complex and / or the human LTBP3-TGFβ1 complex and has one or more of the following properties: i) cross-reactive with mouse LTBP1-proTGFβ1 complex; ii) cross-reactive with mouse LTBP3-proTGFβ1 complex; iii) K<10 nM as measured by BLI D binds to the mouse LTBP1-proTGFβ1 complex; iv) K<10 nM as measured by BLI D binds to the mouse LTBP3-proTGFβ1 complex; v) K for binding to human GARP-proTGFβ1 complex under identical assay conditions D At least 50 times lower than D binds to the human LTBP1-proTGFβ1 complex and / or the human LTBP3-TGFβ1 complex; vi) does not exhibit detectable binding to the human GARP-proTGFβ1 complex when measured by BLI under the same assay conditions used to measure binding to the human LTBP1-proTGFβ1 complex and / or the human LTBP3-TGFβ1 complex; vii) exhibits no detectable binding to LRRC33-proTGFβ1 complexes (e.g., human LRRC33-proTGFβ1 complexes) when measured by BLI under the same assay conditions used to measure binding to human LTBP1-proTGFβ1 complexes and / or human LTBP3-TGFβ1 complexes.

[0029] In some embodiments, the antibody or antigen-binding fragment has at least characteristics (i) through (v) above, and optionally has (vii). In some embodiments, the antibody or antigen-binding fragment has at least characteristics (i) through (iv) and (vi) above, and optionally has (vii). In some embodiments, the antibody or antigen-binding fragment has at least characteristics (i), (iii), and (v) above, and optionally has (vii). In some embodiments, the antibody or antigen-binding fragment has at least characteristics (ii), (iv), and (v) above, and optionally has (vii). In some embodiments, the antibody or antigen-binding fragment has at least characteristics (i), (iii), and (vi) above, and optionally has (vii). In some embodiments, the antibody or antigen-binding fragment has at least characteristics (ii), (iv), and (vi) above, and optionally has (vii). In some embodiments, the antibody or antigen-binding fragment has at least characteristics (ii), (iv), and (vi) above, and optionally has (vii). In some embodiments, the antibody or antigen-binding fragment has at least characteristics (i) through (iii) and (v) above, and optionally has (vii). In some embodiments, the antibody or antigen-binding fragment has at least characteristics (i) through (iii) and (v) above, and optionally has (vii). In some embodiments, the antibody or antigen-binding fragment has at least properties (i)-(iii) and (vi) above, and may have (vii).

[0030] In some preferred embodiments, the antibody or antigen-binding fragment has a K of <5 nM as measured by BLI. D The antibody binds to the human LTBP1-proTGFβ1 complex and the human LTBP3-TGFβ1 complex at a specific concentration, and has all of the above properties (i) to (vii).

[0031] The antibody or antigen-binding fragment can selectively bind to the proTGFβ latent complex presented by LTBP1 / 3 and inhibit the activation of extracellular matrix-associated TGFβ.

[0032] Furthermore, more advantageous isoform-selective inhibitors of TGFβ1 activation have slow dissociation rates (i.e., off-rates, k OFFThe present invention may include monoclonal antibodies (including immunoglobulins and antigen-binding fragments or portions thereof) that exhibit the following activity: (i) a specific agonist (antibody) that specifically binds to the fibrotic protein; (ii) a specific agonist (antibody) that specifically binds to the fibrotic protein; and (iii) a specific agonist (antibody) that specifically binds to the fibrotic protein. The present invention is therefore further based on the recognition that treatment of chronic and progressive diseases such as fibrosis may require inhibitors with good durability, which may be reflected in the dissociation rate of such antibodies.

[0033] The affinity of an antibody for an antigen is typically measured by the equilibrium dissociation constant, or K D The experimentally measured ratio of off and on velocities (k OFF / k ON ) and K D The value of k can be calculated. OFF The value represents the antibody dissociation rate, indicating how quickly it dissociates from its antigen, while k ON The K value represents the antibody association rate, providing information on how quickly the antibody binds to its antigen. The latter is typically concentration-dependent, while the former is concentration-independent. D The value relates to the concentration of the antibody (the amount of antibody needed for a particular experiment) and therefore K D The lower the value (lower the concentration), the higher the affinity of the antibody. Higher affinity antibodies have a lower k relative to the reference antibody. OFF speed, higher k ON It may have a speed, or both.

[0034] k OFF and k ONBoth rates contribute to the overall affinity of a particular antibody for its antigen, and the relative importance or influence of each component may depend on the antibody's mechanism of action. For example, a neutralizing antibody that binds to a mature growth factor (e.g., a soluble, transient TGFβ1 ligand released from a latent complex) must compete with endogenous high-affinity receptors for ligand binding in vivo. Because the ligand-receptor interaction is local and the ligand is short-lived, such an antibody must be able to rapidly target and sequester the soluble growth factor before the ligand finds its cellular receptor in the tissue, thereby activating the TGFβ1 signaling pathway. Therefore, for a ligand-targeted neutralizing antibody to be potent, it must have the ability to bind rapidly to its target growth factor, i.e., a high association rate (k ON ) can be particularly important.

[0035] In contrast, Applicant has determined that antibodies that inhibit TGFβ1 signaling by preventing activation (e.g., release) of mature growth factors from latent complexes ("activation inhibitors") may be preferentially advantageous to have a slow dissociation rate upon binding of the antibody to a target antigen (e.g., proTGFβ1 complex). Unlike neutralizing antibodies, such antibodies do not compete directly with cellular receptors but rather act upstream of signaling by targeting inactive precursor forms (e.g., latent proTGFβ1 complexes) that remain dormant in the tissue environment, thereby preemptively preventing TGFβ1 activation. Such antibodies may confer their inhibitory activity by preventing the release of mature growth factors from latent complexes. For example, such antibodies may function like a "clamp" to confine active growth factors within the prodomain cage structure to maintain them in an inactive (e.g., "latent") state. Indeed, structural analysis, including epitope mapping, has provided insight into the molecular mechanisms underlying the ability of these antibodies to block TGFβ1 activation. In this regard, the Latency Lasso region of the prodomain may be a particularly useful target.

[0036] Antibodies that are able to remain bound to the target upon target binding (e.g., dissociate very slowly from the latent complex) are expected to be advantageous in achieving superior in vivo efficacy due to potency and / or high durability of binding. Based on this recognition, applicants of the present disclosure have developed antibodies that have particularly low k compared to previously described antibodies. OFF Therefore, according to the present invention, preferred antibodies have fast association rates (k ON ) in contrast to the slow dissociation rate (k OFF ) as measured by BLI. Thus, in some embodiments, the antibody, or antigen-binding fragment thereof, has a K of <5 nM as measured by BLI. D and binds to the human LTBP1-proTGFβ1 complex and / or the human LTBP3-TGFβ1 complex at a concentration of 0.05% or more than 0.05% and has one or more of the following properties (which may be in addition to one or a combination of properties (i) to (vii) set forth above): (viii) when bound to a human LTBP1-proTGFβ1 complex and / or a human LTBP3-TGFβ1 complex, it has a molecular weight of ≦5×10 -4 Low dissociation rate (k OFF ) (e.g., measured by a suitable in vitro binding / kinetic assay, e.g., by BLI, e.g., by an Octet-based system); and / or (ix) a long binding half-life (t ) of ≥ 45 minutes when bound to human LTBP1-proTGFβ1 and / or human LTBP3-proTGFβ1 complexes; 1 / 2 ) (e.g., measured by SPR).

[0037] In some preferred embodiments, the antibody or antigen-binding fragment comprises the following six CDRs: a) CDR-H1 containing the amino acid sequence FTFRSYVMH; b) CDR-H2 containing the amino acid sequence VISHEGS(X1)KYYADSVKG, where X1 is L or G; and c) a CDR-H3 comprising the amino acid sequence A(X1)PRIAARRGGFG(X2), where X1 is V, R, or L and X2 is Y, S, or T; d) CDR-L1 comprising the amino acid sequence TRS(X1)G(X2)ID(X3)NYVQ, where X1 is S or H, X2 is N, L, S or A, and X3 is N, D or Y; e) a CDR-L2 comprising the amino acid sequence ED(X1)(X2)RPS, where X1 is N, F, or A and X2 is Q, I, or V; and f) A CDR-L3 comprising the amino acid sequence Q(X1)YD(X2)(X3)(X4)Q(X5)VV, wherein X1 is S or G, X2 is S, F, Y, D, H or W, X3 is N, D or S, X4 is N, A, L, E or T, and X5 is G, R, A or L.

[0038] In some preferred embodiments, the antibody or antigen-binding fragment thereof competes or cross-competes with an antibody (e.g., Ab42) having a heavy chain variable region sequence set forth in SEQ ID NO: 318 and a light chain variable region sequence set forth in SEQ ID NO: 319. The antibody may comprise a heavy chain variable region having an amino acid sequence at least 90% identical to SEQ ID NO: 318 and a light chain variable region having an amino acid sequence at least 90% identical to SEQ ID NO: 319.

[0039] The antibodies or antigen-binding fragments thereof provided herein may, in some preferred embodiments, comprise the following six CDRs (e.g., those of Ab42): CDR-H1 containing the amino acid sequence FTFRSYVMH (SEQ ID NO: 166); CDR-H2 containing the amino acid sequence VISHEGSLKYYADSVKG (SEQ ID NO: 167); CDR-H3 containing the amino acid sequence ARPRIAARRGGFGY (SEQ ID NO: 168); CDR-L1 containing the amino acid sequence TRSSGNIDNNYVQ (SEQ ID NO: 169); CDR-L2 comprising the amino acid sequence EDNQRPS (SEQ ID NO: 170); and CDR-L3 containing the amino acid sequence QSYDYDTQGVV (SEQ ID NO: 171).

[0040] The antibody or antigen-binding fragment may further comprise a heavy chain variable region having an amino acid sequence at least 95% identical (and optionally at least 98% identical) to SEQ ID NO:318 and a light chain variable region having an amino acid sequence at least 95% identical (and optionally at least 98% identical) to SEQ ID NO:319.

[0041] In some alternative embodiments, the antibody, or antigen-binding fragment thereof, comprises the following six CDRs: a) CDR-H1 containing the amino acid sequence GSIRSSSYYWG; b) CDR-H2 containing the amino acid sequence SISYSATTYY; c) a CDR-H3 comprising the amino acid sequence A(X1)DPSYDS(X2)AGM(X3)V, where X1 is S or G, X2 is A or I, and X3 is D or Q; d) a CDR-L1 comprising the amino acid sequence RAS(X1)(X2)IS(X3)YLN, where X1 is K or Q, X2 is V or S, and X3 is S or Y; e) a CDR-L2 comprising the amino acid sequence (X1)AS(X2)(X3)QS, where X1 is Y, A or S, X2 is S or N, and X3 is L or R; f) A CDR-L3 comprising the amino acid sequence QQ(X1)(X2)D(X3)P(X4)T, where X1 is S or G, X2 is F or N, X3 is W or F, and X4 is F or L.

[0042] In some embodiments, the antibody or antigen-binding fragment thereof competes or cross-competes with an antibody (e.g., Ab63) having a heavy chain variable region sequence set forth in SEQ ID NO: 360 and a light chain variable region sequence set forth in SEQ ID NO: 361. The antibody may comprise a heavy chain variable region having an amino acid sequence at least 90% identical to SEQ ID NO: 360 and a light chain variable region having an amino acid sequence at least 90% identical to SEQ ID NO: 361.

[0043] The antibodies or antigen-binding fragments thereof provided herein may comprise the following six CDRs (e.g., those of Ab63): CDR-H1 containing the amino acid sequence GSIRSSSYYWG (SEQ ID NO: 292); CDR-H2 containing the amino acid sequence SISYSATTYY (SEQ ID NO: 293); CDR-H3 containing the amino acid sequence AGDPSYDSIAGMQV (SEQ ID NO: 294); CDR-L1 containing the amino acid sequence RASQSISSYLN (SEQ ID NO: 295); CDR-L2 comprising the amino acid sequence AASNLQS (SEQ ID NO: 296); and CDR-L3 containing the amino acid sequence QQSFDWPLT (SEQ ID NO: 297).

[0044] The antibody or antigen-binding fragment may further comprise a heavy chain variable region having an amino acid sequence at least 95% identical (and optionally at least 98% identical) to SEQ ID NO:360 and a light chain variable region having an amino acid sequence at least 95% identical (and optionally at least 98% identical) to SEQ ID NO:361.

[0045] In one aspect, the invention provides an antibody, or antigen-binding fragment thereof, for use in a method for treating a fibrotic disorder in a subject, wherein the antibody, or antigen-binding fragment thereof, specifically binds to the human LTBP1-proTGFβ complex and / or the human LTBP3-proTGFβ complex, but not to the human GARP-proTGFβ1 complex, wherein: a) the fibrotic disorder includes chronic inflammation; b) the subject would benefit from immunosuppression; c) the subject has or is at risk of developing an autoimmune disease; d) the subject is a candidate for or has undergone allograft transplantation; e) the subject has a high Th17 / Treg ratio; and / or f) the subject is in need of long-term or chronic administration of a TGFβ1 inhibitor. In some embodiments, the subject has or is at risk of developing a metabolic disorder (and the subject may be a subject according to one or more of a)-f)). In some embodiments, the antibody, or antigen-binding fragment thereof, is an isoform-specific LTBP1-proTGFβ1 inhibitor and / or an LTBP3-proTGFβ1 inhibitor.

[0046] The antibody or antigen-binding fragment thereof provided herein can be used in a method for treating a fibrotic disorder in a subject. The fibrotic disorder may include chronic inflammation. The subject may benefit from immunosuppression. The subject may have or be at risk of developing an autoimmune disease. The subject may be a candidate for or have previously undergone allograft transplantation.

[0047] Alternatively, or in addition, the subject may have a high Th17 / Treg ratio. The subject may be in need of long-term or chronic administration of a TGFβ1 inhibitor.

[0048] Alternatively, or in addition, the subject may have or be at risk of developing a metabolic disorder.

[0049] In another aspect, the present invention provides a method for making a composition comprising an antibody or antigen-binding fragment thereof that specifically binds to human LTBP1-proTGFβ complex and / or human LTBP3-proTGFβ complex and does not bind to human GARP-proTGFβ1 complex; wherein the antibody, or antigen-binding fragment thereof, inhibits TGFβ1 but does not inhibit TGFβ2 or TGFβ3, the method comprising the steps of: i) providing at least one antigen comprising LTBP1-proTGFβ1 and / or LTBP3-proTGFβ1; ii) providing an antibody that specifically binds to the at least one antigen of step (i); iii) selecting a first pool of antibodies, or antigen-binding fragments thereof, that inhibit TGFβ1 activation, thereby producing a specific inhibitor of TGFβ1 activation; and iv) formulating the antibodies, or antigen-binding fragments thereof, present in the first pool of antibodies and the second pool of antibodies into a pharmaceutical composition, thereby producing a composition comprising the antibodies, or antigen-binding fragments thereof.

[0050] In one embodiment, the method further comprises removing from the first pool of antibodies or antigen-binding fragments thereof any antibodies or antigen-binding fragments thereof that bind to GARP-proTGFβ1, LRRC33-proTGFβ1, mature TGFβ1, GARP-proTGFβ2, LRRC33-proTGFβ2, mature TGFβ2, GARP-proTGFβ3, LRRC33-proTGFβ3, mature TGFβ3, or any combination thereof. In one embodiment, the method further comprises determining or confirming the isoform specificity of the antibodies or antigen-binding fragments thereof selected in step (ii) and / or (iii). In one embodiment, the method further comprises selecting for antibodies or antigen-binding fragments thereof that are cross-reactive with human and rodent antigens. In one embodiment, the method further comprises producing fully human or humanized antibodies or antigen-binding fragments thereof of the antibodies or antigen-binding fragments thereof present in the first pool of antibodies and the second pool of antibodies.

[0051] In one embodiment, the method further comprises subjecting the antibodies, or antigen-binding fragments thereof, present in the first pool of antibodies and the second pool of antibodies to affinity maturation and / or optimization, thereby providing affinity matured and / or optimized antibodies, or fragments thereof. In one embodiment, the affinity maturation / optimization comprises subjecting the antibodies, or antigen-binding fragments thereof, present in the first pool of antibodies and / or the second pool of antibodies to light chain shuffling as described herein. In one embodiment, the affinity maturation / optimization comprises subjecting the antibodies, or antigen-binding fragments thereof, present in the first, second, and / or third pool of antibodies to CDR H1 / H2 diversification as described herein. In one embodiment, the affinity maturation / optimization comprises subjecting the antibodies, or antigen-binding fragments thereof, to CDR-H3 mutagenesis as described herein. In one embodiment, the affinity maturation / optimization comprises subjecting the antibodies, or antigen-binding fragments thereof, to light chain CDR mutagenesis as described herein. In one embodiment, affinity maturation / optimization comprises subjecting the antibody, or antigen-binding fragment thereof, to light chain CDR L1 / L2 diversification as described herein.

[0052] In one embodiment, the method further comprises determining the affinity of antibodies, or antigen-binding fragments thereof, for human LTBP1-proTGFβ1 and / or human LTBP3-proTGFβ1 from the first and / or second pool of antibodies. In some embodiments, the method comprises determining from the first and / or second pool of antibodies, an affinity of antibodies, or antigen-binding fragments thereof, of >100 nM, >50 nM, >25 nM, or >10 nM, as measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). D The method further comprises the step of removing any antibodies, or antigen-binding fragments thereof, that bind to human LTBP1-proTGFβ1 and / or human LTBP3-proTGFβ1.

[0053] In one embodiment, the method further comprises determining the affinity of antibodies, or antigen-binding fragments thereof, from the first and / or second pool to murine LTBP1-proTGFβ1 and / or murine LTBP3-proTGFβ1. In some embodiments, the method comprises determining from the first and / or second pool of antibodies, or antigen-binding fragments thereof, a K of >100 nM, >50 nM, or >10 nM, as measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). D The method further comprises the step of removing any antibodies, or antigen-binding fragments thereof, that bind to mouse LTBP1-proTGFβ1 and / or mouse LTBP3-proTGFβ1.

[0054] In one embodiment, the method further comprises the step of removing from the first and / or second pool of antibodies, or antigen-binding fragments thereof, any antibodies, or antigen-binding fragments thereof, that do not bind to mouse LTBP1-proTGFβ1 and / or mouse LTBP3-proTGFβ1.

[0055] In one embodiment, the method comprises selecting from the first and / or second pool of antibodies, or antigen-binding fragments thereof, an IC of the antibodies, or antigen-binding fragments thereof, as measured by a suitable functional in vitro cell-based assay, such as the caga assay described herein. 50 In some embodiments, the method further comprises determining an IC of greater than 100 nM, 50 nM, 25 nM, 10 nM, or 5 nM from the first and / or second pool of antibodies, or antigen-binding fragments thereof, as measured by a cell-based assay (e.g., a caga assay) described herein. 50 The method includes removing antibodies, or antigen-binding fragments thereof, having:

[0056] In some embodiments, the method includes obtaining from the first and / or second pool of antibodies, or antigen-binding fragments thereof, an IC of greater than 50 nM or 10 nM as measured by the endogenous LTBP caga assay described herein. 50 The method includes removing antibodies, or antigen-binding fragments thereof, having:

[0057] In some embodiments, the method includes obtaining from the first and / or second pool of antibodies, or antigen-binding fragments thereof, an IC of greater than 50 nM, 25 nM, or 10 nM as measured by the human LTBP overexpression caga assay described herein. 50 The method includes removing antibodies, or antigen-binding fragments thereof, having:

[0058] In some embodiments, the method includes obtaining from the first and / or second pool of antibodies, or antigen-binding fragments thereof, an IC of greater than 50 nM, 25 nM, 10 nM, or 5 nM as measured by the murine LTBP overexpression caga assay described herein. 50 The method includes removing antibodies, or antigen-binding fragments thereof, having:

[0059] Processes and methods for identifying or selecting TGFβ1 selective inhibitors suitable for therapeutic use are encompassed by the present invention, as are methods for making compositions comprising TGFβ1 selective inhibitors. In preferred embodiments, TGFβ1 inhibitors (e.g., selective inhibitors) exhibit the following: i) high affinity (e.g., K) for each of the human LTBP1 / 3-proTGFβ1 complexes; D <5 nM), and ii) a low dissociation rate (k OFF ), e.g., ≦5×10 as measured by a suitable in vitro binding / kinetic assay, e.g., by BLI, e.g., an Octet-based system -4The antibody or antigen-binding fragments include one or more antibodies or antigen-binding fragments having particularly advantageous kinetic criteria characterized by a low dissociation rate (t ) from the human LTBP1-proTGFβ1 and / or human LTBP3-proTGFβ1 complex. 1 / 2 ), for example, may be reflected in a t of ≥ 45 minutes. Preferably, the long dissociation half-life of the antibody or antigen-binding fragment thereof with respect to the matrix-associated complex(es) is combined with a short dissociation half-life with respect to cell-associated complexes, such as the human GARP-proTGFβ1 and / or human LRRC33-proTGFβ1 complex. In particular, preferred antibodies or fragments have a t of ≤ 10 minutes, more preferably ≤ 5 minutes. 1 / 2 The antibody dissociates from the human GARP-proTGFβ1 complex at a specific concentration. Similarly, the method for producing a composition comprising a TGFβ1-selective inhibitor described herein may further comprise the step of selecting such an antibody. The selected antibody or antibodies are evaluated in preclinical studies, including efficacy studies and toxicology / safety studies, using an appropriate preclinical model. The effective dose of the antibody(ies) determined in the efficacy study is below the level that causes undesirable toxicity as determined in the toxicology / safety study. Preferably, an antibody(ies) having a therapeutic window of at least 3-fold, 6-fold, or more preferably 10-fold is selected. The effective dose of the antibody of the present disclosure may be about 0.1 mg / kg to about 30 mg / kg when administered weekly. In a preferred embodiment, the maximum administrable dose (MTD) of the antibody of the present disclosure is >100 mg / kg when administered weekly for at least 4 weeks. In some embodiments, in preclinical toxicology studies, the antibody exhibits a NOAEL of >100 mg / kg / week, >200 mg / kg / week, or >300 mg / kg / week, where the toxicology studies may be 4-week studies, 8-week studies, or 12-week studies. For example, the NOAEL is >100 mg / kg / week in healthy mice or rats following a 12-week subchronic dosing regimen.

[0060] The present disclosure also includes the surprising discovery that inhibition of TGFβ3 with a TGFβ3-selective inhibitor resulted in a pro-fibrotic effect in mice. Similarly, simultaneous inhibition of both TGFβ1 and TGFβ3 in the same model using a combination of a TGFβ1-selective inhibitor and a TGFβ3-selective inhibitor attenuated the anti-fibrotic effect of the TGFβ1 inhibitor. These observations raise the possibility that non-selective TGFβ inhibitors (e.g., pan-inhibitors and TGFβ1 / 3 inhibitors) may actually exacerbate fibrosis. Advantageously, the antibodies disclosed herein (e.g., Ab42 and variants thereof described herein) are isoform-selective, in that they specifically target the latent TGFβ1 complex and do so with a low dissociation rate. Thus, the present invention recognizes that when selecting a particular TGFβ inhibitor for a patient with a fibrotic condition (e.g., a disease involving ECM dysregulation), isoform selectivity should be carefully considered to avoid the risk of exacerbating ECM dysregulation. Thus, the present disclosure includes therapeutic methods that include selecting a TGFβ inhibitor that does not inhibit TGFβ3 for treating a subject having a fibrotic condition (including the preferred fibrotic conditions described herein).

[0061] As used herein, an isoform-selective LTBP1 / 3-proTGFβ1 complex-selective inhibitor may, in some embodiments, be selected from Ab31, Ab34, Ab37, Ab38, Ab39, Ab40, Ab41, Ab42, Ab43, Ab44, Ab45, Ab62, Ab63, and Ab64 (which may be Ab42 or Ab63) (i.e., an antibody or antigen-binding fragment having the heavy and light chain variable regions of the corresponding Ab provided herein), a mutant / derivative thereof, or an antigen-binding fragment thereof, or a modified molecule comprising the antigen-binding fragment thereof. In some preferred embodiments, the LTBP1 / 3-proTGFβ1 complex-selective inhibitor is Ab42, a mutant / derivative thereof, or an antigen-binding fragment thereof, or a modified molecule comprising the antigen-binding fragment thereof. In a preferred embodiment, the LTBP1 / 3-proTGFβ1 complex-selective inhibitor is Ab42 or an antigen-binding fragment thereof. [Brief explanation of the drawings]

[0062] [Figure 1] 10 graphically illustrates that targeting latent forms of TGFβ1 provides isoform and context specificity. [Figure 2] Figure 2 illustrates the identification of latent TGFβ1 isoform- and LTBP complex-specific binders. Figure 2A illustrates that SR-AB1 binds to latent TGFβ1 regardless of the display molecule. SR-AB1 is a human monoclonal antibody discovered by yeast display that selectively binds to latent TGFβ1 and does not detectably bind to latent TGFβ2, TGFβ3, or mature TGFβ1. SR-AB1 cross-reacts with mouse, rat, and cynomolgus monkey proteins and binds to all four latent TGFβ1 complexes. Figure 2B illustrates that SR-AB2 (anti-LTBP1-proTGFβ1 antibody) does not bind to GARP-proTGFβ1 or mature TGFβ1. SR-AB2 cross-reacts with rodent LTBP1-proTGFβ1. [Figure 3]A functional assay (potency assay) for detecting the inhibition of activated recombinant latent TGFβ1 is described. Figure 3A shows the activation of latent TGFβ1 deposited in the extracellular matrix (ECM). In this assay, the presentation molecule is cotransfected with proTGFβ1 into integrin-expressing cells. Transiently transfected cells are plated in assay plates in the presence of inhibitors. The latent LTBP-proTGFβ1 complex is embedded in the ECM. TGFβ reporter cells are then added to the system; free growth factor (released by integrins) signals and is detected by a luciferase assay. Figure 3B shows the activation of latent TGFβ1 presented on the cell surface. The presentation molecule is cotransfected with proTGFβ1 into integrin-expressing cells. Latent TGFβ1 is expressed on the cell surface by GARP or LRRC33. TGFβ reporter cells and inhibitors are then added to the system; free growth factor (released by the integrin) signals and is detected by a luciferase assay. [Figure 4] Figure 4 shows the optimization of recombinant functional assays. Figure 4A shows the relative contribution of the activation of the presentation molecule and / or proTGFβ1 upon cotransfection of the presentation molecule and proTGFβ1. Figure 4B shows the optimization of cotransfection: the ratio of plasmid DNA for the presentation molecule and proTGFβ1. Equal amounts of each plasmid were optimal for cotransfection. [Figure 5] We demonstrate that fibronectin promotes integrin-mediated activation of latent TGFβ1 presented by LTBP. Assay plates were pre-coated with fibronectin purified from human plasma. Fibronectin enhances integrin-mediated activation of latent TGFβ1 presented by LTBP1 and / or LTBP3. [Figure 6]1 is a graph illustrating that SR-AB1 is a context-independent inhibitor of TGFβ1 activation. SR-AB1 was shown to inhibit integrin-dependent activation of TGFβ1 regardless of the presentation molecule. [Figure 7] We provide data confirming LTBP-selective inhibition of the TGFβ1 large latent complex (LLC). Figure 7A illustrates that SR-AB2 specifically binds to the LTBP-proTGFβ1 complex; it does not bind to proTGFβ1 or LTBP1 alone. SR-AB2 also does not bind to GARP-proTGFβ1. Figure 7B shows that SR-AB2 inhibits integrin-mediated activation of LTBP1-proTGFβ1 (human and mouse complexes). Figure 7C shows that SR-AB2 inhibits integrin-mediated activation of LTBP3-proTGFβ1. [Figure 8] The heavy and light chain variable region sequences of SR-AB2 (SEQ ID NOS: 7-8, respectively, in order of appearance) are provided. Complementarity determining regions (CDRs) are underlined. [Figure 9] 1 is a graph illustrating the binding specificity of SR-AB2 to LTBP1-proTGFβ1 and LTBP3-proTGFβ1 complexes. [Figure 10] We present data demonstrating the context-selective inhibition of matrix-associated TGFβ1 activation by SR-AB2. Figure 10A illustrates that SR-AB2 inhibits LTBP-proTGFβ, where transfected proTGFβ1 is expressed by endogenous LTBP1 / 3. Figure 10B illustrates that SR-AB2 does not inhibit TGFβ1 activation expressed by GARP. These assays were performed in LN229 cells expressing high LTBP3 mRNA, low LTBP1 mRNA, undetectable GARP, and undetectable LRRC33. TGFβ activity normalized to vehicle is shown on the y-axis. [Figure 11] Binding profiles and affinity data are provided for the LTBP complex-specific antibodies SR-AB10, SR-AB2, and SR-13. [Figure 12]12A and 12B are graphs showing the improved potency of optimized LTBP complex-specific antibodies. Figure 12A provides a graph showing the improved inhibitory potency of SR-AB14 (optimized SR-AB10) as measured by a cell-based TGFβ reporter assay. Figure 12B provides a graph showing the improved inhibitory potency of SR-AB15 (optimized SR-AB13) as measured by a cell-based TGFβ assay. [Figure 13] Figures 13A and 13B are graphs showing the improved potency of optimized LTBP complex-specific antibodies (i.e., SR-AB20, SR-AB21, SR-AB22, and SR-AB23) after CDR-H3 mutagenesis, as measured by a cell-based TGFβ reporter assay. [Figure 14] Figures 14A and 14B are graphs showing the improved potency of optimized LTBP complex-specific antibodies (i.e., SR-AB24, SR-AB25, SR-AB26, SR-AB27, SR-AB28, and SR-AB29) after CDR-H3 mutagenesis, as measured by a cell-based TGFβ reporter assay. [Figure 15] 1 is a graph showing that affinity matured antibodies exhibit specific binding to the LTBP-proTGFβ1 complex. [Figure 16] 1 is a graph showing the improved potency of optimized LTBP complex-specific antibodies after cycles 1, 2 and 3 of antibody optimization as measured by a cell-based TGFβ reporter assay. [Figure 17] 1 shows the results of an enzyme-linked immunosorbent assay (ELISA) showing antibody binding to baculovirus (BV) particles, which tests antibody polyspecificity. [Figure 18] 1 shows the results of an affinity capture self-interaction nanoparticle spectroscopy (AC-SINS) assay, which tests antibody self-interaction. An increase in plasmon wavelength indicates self-interaction. [Figure 19]1 is a graph showing that treatment with SR-AB42 and SR-AB31 inhibited the increase in hydroxyproline (HYP) (μg / mg tissue) in liver tissue in animals on a choline-deficient high-fat diet (CDHFD). [Figure 20] Figure 20A is a graph showing the relative ratio of phosphorylated to total (phosphorylated and non-phosphorylated) Smad2 / 3 (pSMAD2 / 3:tSMAD2 / 3) in the Alport mouse model. A single dose of SR-AB42 or SR-AB63 was sufficient to significantly inhibit pSmad2 / 3 signaling in whole kidney lysates. Figure 20B is a graph showing the amount of phosphorylated SMAD2 / 3 (pSMAD2 / 3) determined by ELISA, and Figure 20C is a graph showing the amount of total SMAD2 / 3 (tSMAD2 / 3) protein determined by ELISA. As shown by Figures 20B and 20C, a decrease in pSMAD contributes to the change in the ratio shown in Figure 20A. [Figure 21] 1 is a graph showing that lead cycle 3 antibodies show no inhibition in the LTBP-TGFβ3 assay. [Figure 22] Five representative PSR staining images from CDHFD mice treated with control, reference Ab, TGFβ3 inhibitor, or both are shown (left). A graph showing the Picrosirius Red area (%) within liver sections from CDHFD mice treated with reference Ab, TGFβ3 inhibitor, or both compared to control is also provided (right). [Figure 23] We show that LTBP-complex antibodies such as SR-AB63 are highly specific and have picomolar monovalent affinity. [Figure 24] We show that LTBP-complex antibodies such as SR-AB42 are highly specific and have picomolar monovalent affinity. DETAILED DESCRIPTION OF THE INVENTION

[0063] The present invention provides compositions useful for reducing the activation of TGFβ. Inhibitors that target the latent proTGFβ complex upstream of growth factor-receptor interaction are generally referred to as TGFβ activation inhibitors.

[0064] To date, four presentation molecules for TGFβ have been identified: latent TGFβ-binding protein 1 ("LTBP1"), latent TGFβ-binding protein 3 ("LTBP3"), glycoprotein A repeat-dominant ("GARP"), and leucine-rich repeat-containing protein 33 ("LRRC33"). Each of these presentation molecules can form disulfide bonds with the homodimeric proprotein complex of the TGFβ precursor, i.e., proTGFβ. The proTGFβ complex remains dormant (latent) within its respective extracellular niche (e.g., ECM and immune cell surface) until an activation event triggers the release of soluble growth factor from the complex.

[0065] Compared with the ubiquitously expressed TGFβ growth factor and receptor, presentation molecules exhibit more restricted or selective (e.g., tissue-specific) expression patterns, resulting in functional compartmentalization of TGFβ activity. The four presentation molecule-proTGFβ complexes, i.e., LTBP1-proTGFβ, LTBP3-proTGFβ, GARP-proTGFβ, and LRRC33-proTGFβ, therefore provide distinct "contexts" of TGFβ signaling in the tissues in which they are expressed. These contexts can be divided into two broad categories: i) ECM-associated TGFβ signaling (e.g., matrix-associated TGFβ function); and ii) cell-associated TGFβ signaling (e.g., specific immune cell function). LTBP1-proTGFβ and LTBP3-proTGFβ complexes fall into the first category, and GARP-proTGFβ and LRRC33-proTGFβ complexes fall into the second category. Thus, disclosed herein are inhibitors of TGFβ that can selectively inhibit activation of TGFβ associated with ECM. In some embodiments, the inhibitors are also selective with respect to particular TGFβ isoforms (e.g., proTGFβ1, proTGFβ2, and / or proTGFβ3).

[0066] In exemplary embodiments, the compositions described herein are useful for selectively reducing TGFβ1 activation in the context of LTBP proteins, e.g., LTBP1 and / or LTBP3 proteins. Such compositions advantageously inhibit activation of extracellular matrix-associated TGFβ1 without inhibiting TGFβ1 in the context of the immune-related TGFβ1-presenting molecules GARP and LRRC33. The compositions described herein are useful for treating disorders associated with TGFβ1 activation, e.g., fibrotic disorders. Thus, in one embodiment, the present invention provides compositions that reduce TGFβ1 activation, methods of use, methods of manufacture, and methods of treatment. Methods for selecting a TGFβ1 inhibitor for a subject exhibiting symptoms of a fibrotic disorder are also provided.

[0067] definition In order to make this disclosure more easily understandable, certain terms are first defined. These definitions should be read in light of the remainder of this disclosure as understood by those skilled in the art. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Further definitions are set forth throughout the detailed description.

[0068] Affinity: Affinity is the strength of binding of a molecule (e.g., an antibody) to its ligand (e.g., an antigen). It is typically measured as the equilibrium dissociation constant (K D ) is measured and reported by K D is the antibody association rate ("on rate" or K on ) (how quickly it binds to its antigen) versus its dissociation rate ("off rate" or K off ) (how quickly it dissociates from its antigen). For example, an antibody with an affinity of ≦1 μM will have a K of ≦1 μM as determined by a suitable in vitro binding assay. D A suitable in vitro assay, such as biolayer interferometry (e.g., Octet) or surface plasmon resonance (e.g., Biacore System), can be used to determine the K value based on well-known methods. D The affinity measured by the value can be evaluated.

[0069] Affinity maturation: Affinity maturation is a type of antibody optimization and is a process of improving the affinity of an antibody or fragment for its antigen, typically involving making one or more changes to the amino acid sequence of the antibody or fragment to achieve higher affinity. Typically, the parent antibody and the affinity-matured counterpart retain the same epitope. Affinity maturation may involve diversification and / or mutagenesis of one or more CDR sequences.

[0070] antibody:The term "antibody" encompasses any naturally occurring, recombinant, modified, or engineered immunoglobulin or immunoglobulin-like structure, or antigen-binding fragment or portion thereof, or derivatives thereof, as further described elsewhere herein. Thus, the term refers to an immunoglobulin molecule that specifically binds to a target antigen, including, for example, chimeric, humanized, fully human, and bispecific antibodies. Unless otherwise specified, the term "antibody" as used herein includes antigen-binding fragments and variants thereof. Intact antibodies generally contain at least two full-length heavy chains and two full-length light chains, but in some cases may contain fewer chains, such as antibodies naturally occurring in camelids, which may contain only heavy chains. Antibodies may be derived from a single source or may be "chimeric," i.e., different portions of the antibody may be derived from two different antibodies. Antibodies, or antigen-binding portions thereof, may be produced in hybridomas by recombinant DNA technology or by enzymatic or chemical cleavage of intact antibodies. As used herein, the term "antibody" includes monoclonal antibodies, bispecific antibodies, minibodies, domain antibodies, synthetic antibodies (sometimes referred to herein as "antibody mimetics"), chimeric antibodies, humanized antibodies, human antibodies, and antibody fusions (sometimes referred to herein as "antibody conjugates"). In some embodiments, the term also encompasses peptibodies.

[0071] antigen:The term "antigen" broadly includes any molecule containing an antigenic determinant within the binding domain(s) to which an antibody or fragment specifically binds. An antigen can be a single unit molecule (e.g., a protein monomer or fragment) or a complex composed of multiple components. An antigen provides an epitope, e.g., a molecule or portion of a molecule, or a complex of molecules or portions of molecules, that can be bound by a selective binding agent, e.g., an antigen-binding protein (including, e.g., an antibody). Thus, a selective binding agent can specifically bind to an antigen formed by two or more components in a complex. In some embodiments, an antigen can be used in an animal to generate antibodies capable of binding to the antigen. An antigen may possess one or more epitopes capable of interacting with different antigen-binding proteins, e.g., antibodies. In the context of the present disclosure, suitable antigens are complexes (e.g., multimeric complexes composed of associated components), including proTGF dimers ("small latent complexes" or SLCs), preferably associated with a presentation molecule (together, "large latent complexes" or LLCs). Each monomer of a proTGF dimer contains a prodomain and a growth factor domain separated by a furin cleavage sequence. Two such monomers form a proTGF dimer complex, which then covalently binds to a presentation molecule via a disulfide bond involving cysteine ​​residues present near the N-terminus of each proTGF monomer. This multimeric complex formed by proTGF dimers bound to a presentation molecule is generally referred to as a large latent complex. Antigen complexes suitable for screening antibodies or antigen-binding fragments include, for example, the presentation molecule component of the large latent complex. Such presentation molecule components may be the full-length presentation molecule or a fragment(s) thereof. The minimum required portion of a presentation molecule is typically at least 50 amino acids, but more preferably at least 100 amino acids, of the presentation molecule polypeptide, including two cysteine ​​residues capable of forming covalent bonds with the proTGFβ1 dimer.

[0072] Antigen-binding portion / fragment:As used herein, the term "antigen-binding portion" or "antigen-binding fragment" of an antibody refers to one or more fragments of an antibody that retain the ability to specifically bind to an antigen (e.g., LTBP1-proTGFβ1 and LTBP3-proTGFβ1). Antigen-binding portions include, but are not limited to, any naturally occurring, enzymatically obtainable, synthetic, or genetically engineered polypeptide or glycoprotein that specifically binds to an antigen to form a complex. In some embodiments, an antigen-binding portion of an antibody may be obtained from an intact antibody molecule using any suitable standard technique, such as proteolytic or recombinant genetic engineering techniques, including, for example, the manipulation and expression of DNA encoding the variable (and optionally constant) domains of the antibody. Non-limiting examples of antigen-binding portions include: (i) a Fab fragment (a monovalent fragment consisting of the VL, VH, CL, and CH1 domains); (ii) a F(ab')2 fragment (a bivalent fragment comprising two Fab fragments linked by a disulfide bridge at the hinge region); (iii) a Fd fragment consisting of the VH and CH1 domains; (iv) a Fv fragment consisting of the VL and VH domains of a single arm of an antibody; (v) a single-chain Fv (scFv) molecule (see, e.g., Bird et al. (1988) SCIENCE 242:423-426; and Huston et al. (1988) PROC. NAT'L. ACAD. SCI. USA 85:5879-5883); (vi) a dAb fragment (see, e.g., Ward et al. (1989) NATURE 341:544-546); and (vii) a minimal recognition unit (e.g., an isolated complementarity-determining region (CDR)) consisting of amino acid residues that mimic the hypervariable region of an antibody. Other forms of single-chain antibodies, such as diabodies, are also encompassed.The term antigen-binding portion of an antibody also includes a "single-chain Fab fragment," known as an "scFab," comprising an antibody heavy chain variable domain (VH), an antibody constant domain 1 (CH1), an antibody light chain variable domain (VL), an antibody light chain constant domain (CL) and a linker, wherein the antibody domains and the linker are in one of the following orders, from N-terminal to C-terminal: a) VH-CH1-linker-VL-CL, b) VL-CL-linker-VH-CH1, c) VH-CL-linker-VL-CH1 or d) VL-CH1-linker-VH-CL; wherein the linker is a polypeptide of at least 30 amino acids, preferably 32 to 50 amino acids.

[0073] Progressive fibrosis: As used herein, a subject suffers from advanced fibrosis when they have a progressive stage of a fibrotic disorder, particularly organ fibrosis, which makes the patient a candidate for receiving or requiring an allograft transplant.

[0074] as needed:In the context of a dosing regimen, the term "as needed" refers to a dosing regimen that is not based on a predetermined dosing schedule, but instead is based on one or more parameters or markers that are measured or monitored periodically during treatment, which provide information or guidance regarding whether additional doses would be beneficial to the subject / patient. For example, a pharmaceutical composition comprising a TGFβ inhibitor, such as a TGFβ1 / 2 / 3 inhibitor (a "pan" inhibitor), a TGFβ1 / 2 inhibitor, and a TGFβ1 / 3 inhibitor, may be administered intermittently on an "as needed" basis, in a therapeutically effective amount sufficient to achieve and / or maintain a clinical benefit (e.g., a reduction in one or more clinical markers of fibrosis). In some embodiments, administration of an LTBP1 / 3-complex-selective TGFβ inhibitor, such as any one of the antibodies disclosed herein (e.g., Ab31, Ab34, Ab37, Ab38, Ab39, Ab40, Ab41, Ab42, Ab43, Ab44, Ab45, Ab62, Ab63, or Ab64 (which may be Ab42)), may be used in combination with a method for determining or monitoring therapeutic efficacy. In some embodiments, an LTBP1 / 3-complex-selective TGFβ inhibitor is administered to a patient only if clinical benefit is expected from an additional dose of the TGFβ inhibitor. To manage toxicity, it is contemplated that intermittent or "as needed" dosing regimens may be required more frequently with non-isoform-selective inhibitors of TGFβ compared to TGFβ1-selective inhibitors such as those disclosed herein.

[0075] bias:In the context of the present disclosure, the term "bias" refers to skewed or unequal affinities toward or for a subset of antigens to which an antibody can specifically bind. For example, an antibody is said to be biased if its affinity for one antigen complex is not equivalent to its affinity for another antigen complex (e.g., by more than a five-fold difference in affinity). An antibody characterized as "unbiased" has approximately equal affinities toward such antigen complexes (e.g., by less than a five-fold difference in affinity). Antibodies of the present disclosure "selectively" bind to EMC-associated complexes (LTBP1-proTGFβ1 and LTBP3-proTGFβ). Such selective binding may, in some embodiments, include binding with a greater than 50-fold relative affinity between at least one matrix-associated complex and at least one (preferably both) cell-associated complexes (GARP-proTGFβ1 and / or LRRC33-proTGFβ1 complexes).

[0076] Biolayer Interferometry (BLI): BLI is a label-free technique for optically measuring biomolecular interactions, for example, between a ligand immobilized on a biosensor chip surface and an analyte in solution. BLI offers the ability to precisely and accurately monitor binding specificity, association and dissociation rates, or concentration. BLI platform instruments are commercially available, for example, from ForteBio, and are commonly referred to as the Octet® System. BLI can be used to perform the in vitro binding assays described herein.

[0077] Autoimmune diseases: Autoimmune diseases are conditions caused by an abnormal or overactive immune response against normal body parts. The administration of immunostimulants to such patients with autoimmune conditions can worsen the condition.

[0078] Cell-associated proTGFβ1:The term refers to membrane-bound (e.g., cell surface-anchored) TGFβ1 or its signaling complex (e.g., pro / latent TGFβ1). Typically, such cells are immune cells. TGFβ1 presented by GARP or LRRC33 is cell-associated TGFβ1. GARP and LRRC33 are transmembrane presentation molecules presented on the cell surface of certain cells. GARP-proTGFβ1 and LRRC33-proTGFβ1 can be collectively referred to as "cell-associated (or "cell surface") proTGFβ1 complexes," which mediate cell-associated (e.g., immune cell-associated) TGFβ1 activation / signaling.

[0079] Chronic inflammation: In the context of the present disclosure, fibrotic disorders associated with chronic inflammation are characterized by continuous or persistent damage to tissues that does not resolve with standard treatment after the initial injury.Chronic inflammation refers to a long-term inflammatory response, including gradual changes in the types of cells present at the site of inflammation (e.g., fibrotic tissue).It is characterized by simultaneous destruction and repair of tissues from the inflammatory process.It may involve acute inflammation, or may be a long-term, low-grade type.

[0080] Clinical benefit: As used herein, the term "clinical benefit" is intended to include both the efficacy and safety of a therapy. Thus, a therapeutic treatment that achieves a desired clinical benefit is both effective and safe (e.g., has tolerable or acceptable toxicity or adverse events).

[0081] Combinatory or combinatorial epitopes:A combinatorial epitope is an epitope recognized and bound by a combinatorial antibody at a site (i.e., antigenic determinants) formed by non-contiguous portions of an antigen's component(s) that are in close proximity in the three-dimensional structure to form the epitope. Thus, the antibodies of the present invention may bind to an epitope formed by two or more components (e.g., portions or segments) of the pro / latent TGF-β1 complex. A combinatorial epitope may include an amino acid residue(s) from a first component of the complex and an amino acid residue(s) from a second component of the complex. Each component may be from a single protein or two or more proteins of the antigenic complex. A combinatorial epitope is formed by structural contributions from two or more components (e.g., portions or segments, e.g., amino acid residues) of an antigen or antigen complex.

[0082] Complementarity determining region: As used herein, the term "CDR" refers to a complementarity-determining region in an antibody variable sequence. There are three CDRs in each of the heavy and light chain variable regions, designated CDR1, CDR2, and CDR3 for each variable region. The exact boundaries of these CDRs are defined differently according to different systems. The system described by Kabat (Kabat et al. (1987; 1991) Sequences of Proteins of Immunological Interest (National Institutes of Health, Bethesda, Md.)) not only provides an unambiguous residue numbering system applicable to any variable region of an antibody, but also provides the exact residue boundaries that define the three CDRs in each of the heavy and light chains. These CDRs may be referred to as Kabat CDRs.

[0083] Conformational epitopes:A conformational epitope is an epitope that is recognized and bound by a conformational antibody in a three-dimensional conformation, but not by an unfolded peptide of the same amino acid sequence. A conformational epitope can be called a conformation-specific epitope, a conformation-dependent epitope, or a conformation-sensitive epitope. The corresponding antibody or its fragment that specifically binds to such an epitope can be called a conformation-specific antibody, a conformation-selective antibody, or a conformation-dependent antibody. The binding of an antigen to a conformational epitope depends on the three-dimensional structure (conformation) of the antigen or antigen complex.

[0084] Context-specific: Context-specific (or context-selective) antibodies of the present invention (in contrast to "context-independent" antibodies) can selectively bind to a subset, but not all, of the proTGFβ1 complexes associated with a particular biological context. For example, matrix-selective targeting allows for specific inhibition of TGFβ1 function associated with the ECM. ECM-selective inhibition can be achieved by using antibodies or fragments thereof that selectively target the ECM components LTBP1-proTGFβ1 and / or LTBP3-proTGFβ1. The antibodies and fragments disclosed herein therefore represent a class of context-specific antibodies. LTBP1-specific and LTBP3-specific inhibitors of TGFβ1 activation are also context-specific antibodies.

[0085] Cross-block / cross-blocking:A first antibody or antigen-binding portion thereof and a second antibody or antigen-binding portion thereof cross-block each other with respect to the same antigen, as measured, for example, by biolayer interferometry (e.g., Octet) or surface plasmon resonance (e.g., Biacore System) assays using standard test conditions, e.g., according to the manufacturer's instructions (e.g., binding is assayed at room temperature, approximately 20-25°C). The first antibody or fragment thereof and the second antibody or fragment thereof may have the same epitope; they may have non-identical but overlapping epitopes; or they may have distant (different) epitopes (close proximity in three-dimensional space cross-blocks antibody binding through steric hindrance). "Cross-blocking" means that binding of the first antibody to an antigen prevents binding of the second antibody to the same antigen, and similarly, binding of the second antibody to an antigen prevents binding of the first antibody to the same antigen.

[0086] Dissociation rate: The term "dissociation rate" as used herein has the meaning understood by those skilled in the relevant field (e.g., antibody technology) and refers to a kinetic parameter measured by how fast / slow a ligand (e.g., antibody or fragment) dissociates from its binding target (e.g., antigen). The dissociation rate can be expressed as the "off" rate ("k OFF The relative on / off rates (i.e., k ON and k OFF ) determines the overall strength of the interaction, or affinity, and is typically expressed as the dissociation constant, or K D Therefore, equivalent affinities (e.g., K D value) indicates fast association (high k ON ), slow dissociation (low k OFF), or by having contributions from both factors. Monovalent interactions can be measured by using monovalent antigen-binding molecules / fragments, such as fAb (Fab), and bivalent interactions can be measured by using bivalent antigen-binding molecules, such as whole immunoglobulins (e.g., IgGs). Dissociation kinetics can be measured by the dissociation half-life (often also called half binding time), i.e., t 1 / 2 Dissociation half-life can be expressed in terms of the time it takes for half of the antibody molecules (e.g., mAb, Fab, etc.) to dissociate from the bound antigen. Thus, antibodies with slow dissociation rates have long dissociation half-lives, and antibodies with fast dissociation rates have short dissociation half-lives.

[0087] Dosage: As used herein, typical therapeutic dosages of antibodies of the invention range from about 1 to 30 mg / kg per dose. Typical dosing regimens may include once every week, once every two weeks, once every three weeks, once every four weeks, once a month, once every six weeks, etc.

[0088] ECM-associated (or "matrix-associated") TGFβ1: The term refers to TGFβ1 or its signaling complexes (e.g., pro / latent TGFβ1) that are components of (e.g., deposited within) the extracellular matrix. TGFβ1 presented by LTBP1 or LTBP3 is ECM-associated TGFβ1.

[0089] Effective dose: An "effective amount" (or therapeutically effective amount) is a dosage or administration regimen that achieves a statistically significant clinical benefit in a patient population.

[0090] Fibrotic disorders: The term "fibrosis" or "fibrotic condition / disorder" refers to a process or indication characterized by the pathological accumulation of extracellular matrix (ECM) components, such as collagen, in a tissue or organ. Fibrosis can include primary fibrosis as well as secondary fibrosis associated with disease or disorder.

[0091] GARP-proTGFβ1: As used herein, the term "GARP-proTGFβ1" refers to a protein complex containing the proprotein form or latent form of the transforming growth factor-β1 (TGFβ1) protein associated with glycoprotein A repeat-dominant protein (GARP) or a fragment or variant thereof. The proTGFβ1 homodimer can form a covalent bond with a single molecule of GARP via a disulfide bond. The terms "GARP-TGFβ1" may be used interchangeably. GARP-proTGFβ1 expression is restricted to certain cell types, such as regulatory T cells (Tregs).

[0092] Human antibodies: As used herein, the term "human antibody" is intended to include antibodies having variable and constant regions derived from human germline immunoglobulin sequences. The human antibodies of the present disclosure may include amino acid residues not encoded by human germline immunoglobulin sequences (e.g., mutations introduced by random or site-specific mutagenesis in vitro or by somatic mutation in vivo), for example, within the CDRs, particularly CDR3 (e.g., CDR-H3 or CDR-L3 mutagenesis).

[0093] Humanized antibodies: The term "humanized antibody" refers to an antibody that contains heavy and light chain variable region sequences derived from a non-human species (e.g., mouse), but in which at least a portion of the VH and / or VL sequences have been altered to make them more "human-like," i.e., more similar to human germline variable sequences. One type of humanized antibody is a CDR-grafted antibody.

[0094] Immune suppression / immunosuppression: The term "immunosuppression" refers to the suppression or reduction in the strength of the body's immune system. Patients who would "benefit from immunosuppression" include those with advanced stages of organ fibrosis, who are candidates for, are considered for, or have undergone transplantation.

[0095] Isoform-specific:The term "isoform specificity" refers to the ability of an agent to distinguish one isoform from other structurally related isoforms (i.e., selectivity). An isoform-specific TGFβ inhibitor, at a given concentration, exerts inhibitory activity against one isoform of TGFβ but not against other isoforms of TGFβ. For example, an isoform-specific TGFβ1 antibody selectively binds to TGFβ1. A TGFβ1-specific inhibitor (antibody) preferentially targets (binds to and thereby inhibits) the TGFβ1 isoform over TGFβ2 or TGFβ3 with substantially higher affinity. For example, selectivity in this context may refer to at least a 500- to 1000-fold difference in the respective affinities as measured by in vitro binding assays such as Octet and Biacor. In some embodiments, selectivity refers to the failure of an inhibitor to inhibit TGFβ2 and TGFβ3 when used at a dosage effective to inhibit TGFβ1 in vivo. The context-specific inhibitors of the present disclosure are also isoform-specific.

[0096] Isolated: As used herein, an "isolated" antibody refers to an antibody that is substantially free from other antibodies of different antigenic specificities. In some embodiments, an isolated antibody is substantially free from other unintended cellular material and / or chemicals.

[0097] Long-term or chronic administration: As used herein, a therapeutic regimen that includes more than six months of treatment is considered long-term. In some patient populations, a long-term therapeutic regimen includes administration of a drug (e.g., a context-selective TGFβ1 inhibitor) for an indefinite period of time.

[0098] LRRC33-proTGFβ1:As used herein, the term "LRRC33-TGFβ1 complex" refers to a complex between the proprotein or latent form of transforming growth factor-β1 (TGFβ1) protein and leucine-rich repeat-containing protein 33 (LRRC33; also known as negative regulator of reactive oxygen species, or NRROS), or a fragment or variant thereof. In some embodiments, the LRRC33-TGFβ1 complex comprises LRRC33 covalently bound to the pro / latent form of TGFβ1 via one or more disulfide bonds. In other embodiments, the LRRC33-TGFβ1 complex comprises LRRC33 non-covalently bound to the pro / latent form of TGFβ1. In some embodiments, the LRRC33-TGFβ1 complex is a naturally occurring complex, e.g., an intracellular LRRC33-TGFβ1 complex.

[0099] LTBP1-TGFβ1: As used herein, the term "LTBP1-TGFβ1 complex" (or "LTBP1-proTGFβ1 complex") refers to a protein complex comprising the proprotein form or latent form of transforming growth factor-β1 (TGFβ1) protein (which may be referred to herein as "proTGFβ1") and latent TGF-β binding protein 1 (LTBP1) or a fragment or variant thereof. In some embodiments, the LTBP1-TGFβ1 complex comprises LTBP1 covalently bound to pro / latent TGFβ1 via one or more disulfide bonds. In other embodiments, the LTBP1-TGFβ1 complex comprises LTBP1 non-covalently bound to pro / latent TGFβ1. In some embodiments, the LTBP1-TGFβ1 complex is a naturally occurring complex, e.g., an intracellular LTBP1-TGFβ1 complex. An exemplary LTBP1-TGFβ1 complex is shown in FIG. 3.

[0100] LTBP3-TGFβ1:As used herein, the term "LTBP3-TGFβ1 complex" (or "LTBP3-proTGFβ1 complex") refers to a protein complex comprising the proprotein or latent form of transforming growth factor-β1 (TGFβ1) protein (which may be referred to herein as "proTGFβ1") and latent TGF-β binding protein 3 (LTBP3) or a fragment or variant thereof. In some embodiments, the LTBP3-TGFβ1 complex comprises LTBP3 covalently bound to pro / latent TGFβ1 via one or more disulfide bonds. In other embodiments, the LTBP3-TGFβ1 complex comprises LTBP1 non-covalently bound to pro / latent TGFβ1. In some embodiments, the LTBP3-TGFβ1 complex is a naturally occurring complex, e.g., an intracellular LTBP3-TGFβ1 complex. An exemplary LTBP3-TGFβ1 complex is shown in FIG. 3.

[0101] Macrophages:Macrophages are a type of white blood cell of the immune system and comprise a heterogeneous, phenotypically diverse subpopulation of myeloid cells. Some macrophages differentiate from circulating monocytes derived from bone marrow, while others are tissue-specific macrophages ("resident" macrophages) residing within specific anatomical or tissue locations. Tissue-specific macrophages include, but are not limited to, adipose tissue macrophages; Kupffer cells (liver); sinus histiocytes (lymph nodes); alveolar macrophages (or dust cells, alveoli of the lungs); tissue macrophages (histiocytes) that lead to giant cells (connective tissue); Langerhans cells (skin and mucous membranes); microglia (central nervous system); Hofbauer cells (placenta); intraglomerular mesangial cells (kidneys); osteoclasts (bone); epithelioid cells (granulomas); red pulp macrophages (or sinusoidal endothelial cells, red pulp of the spleen); peritoneal macrophages (peritoneal cavity); and LysoMac (Peyer's patches). Macrophages, e.g., bone marrow-derived monocytes, can be activated by specific stimuli (e.g., cytokines) to result in polarized phenotypes, e.g., M1 and M2. M2-biased activated macrophages are further classified into several phenotypically distinct subtypes, e.g., M2a, M2b, M2c (e.g., pro-fibrotic), and M2d (pro-tumor or Tam-like).

[0102] Matrix-associated proTGFβ1: LTBP1 and LTBP3 are presentation molecules that are components of the extracellular matrix (ECM). LTBP1-proTGFβ1 and LTBP3-proTGFβ1 can be collectively referred to as the "ECM-associated" (or "matrix-associated") proTGFβ1 complex, which mediates ECM-associated TGFβ1 activation / signaling.

[0103] Maximum Total Dosage (MTD): The term MTD generally refers to the highest dose of a test article (e.g., a TGFβ1 inhibitor) evaluated at the no observed adverse effect level (NOAEL) in the context of safety / toxicology considerations. For example, the NOAEL for Ab2 in rats was the highest dose evaluated (100 mg / kg) based on a 4-week toxicology study, suggesting that the MTD for Ab2 is >100 mg / kg.

[0104] Myeloid-derived suppressor cells: Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of cells produced during various pathological conditions and are thought to represent the pathological state of activation of monocytes and relatively immature neutrophils. MDSCs comprise at least two cell categories, termed i) "granulocytic" (G-MDSC) or polymorphonuclear (PMN-MDSC), which phenotypically and morphologically resemble neutrophils; and ii) "monocytic" (M-MDSC), which phenotypically and morphologically resemble monocytes. MDSCs are characterized by distinct sets of genomic and biochemical properties and can be distinguished by specific surface molecules. For example, human G-MDSCs / PMN-MDSCs typically express the cell surface markers CD11b, CD33, CD15, and CD66. Furthermore, human G-MDSCs / PMN-MDSCs may also express HLA-DR and / or arginase. In contrast, human M-MDSCs typically express the cell surface markers CD11b, CD33, and CD14. MDSCs also express CD39 and CD73, which may mediate adenosine signaling, which is involved in organ fibrosis (e.g., liver fibrosis and pulmonary fibrosis), cancer, and bone marrow fibrosis. Furthermore, human M-MDSCs may also express HLA-DR. In addition to these cell surface markers, MDSCs are characterized by their ability to suppress immune cells such as T cells, NK cells, and B cells. The immunosuppressive function of MDSCs may include the inhibition of antigen-nonspecific and antigen-specific functions. MDSCs may express cell surface LRRC33 and / or LRRC33-proTGFβ1.

[0105] Myofibroblasts: Myofibroblasts are cells with a specific phenotype of fibroblasts and smooth muscle cells, and generally express vimentin, alpha-smooth muscle actin (α-SMA; human gene ACTA2), and palladin. In many disease states involving extracellular matrix dysregulation (such as increased matrix stiffness), normal fibroblasts are dedifferentiated into myofibroblasts in a TGFβ-dependent manner.

[0106] Off speed(kOFF ): The off-rate is a kinetic parameter for how fast or how slowly an antibody (e.g., mAb) or antigen-binding fragment (e.g., fAb) dissociates from its antigen, and may also be referred to as the dissociation rate. The dissociation rate can be measured experimentally in suitable in vitro binding assays, such as BLI (Octet®) and / or SPR (Biacore)-based systems. In the context of antibody-antigen binding kinetics, the term "half-binding-time" (T 1 / 2 ) or "dissociation half-time" refers to the duration required for half of the antibody molecules (e.g., mAb, Fab) to dissociate from the bound antigen (e.g., LTBP1-proTGFβ1, LTBP3-proTGFβ1). Thus, antibodies that dissociate slowly from antigen (i.e., have a low off-rate) have a long T 1 / 2 Conversely, antibodies that dissociate rapidly from antigen (i.e., have a high off rate) have a short T 1 / 2 It has.

[0107] Pan-TGFβ inhibitors / pan-inhibition of TGFβ: The term "pan-TGFβ inhibitor" refers to any agent capable of inhibiting or antagonizing all three isoforms of TGFβ. Such inhibitors may be small molecule inhibitors of TGFβ isoforms. The term includes pan-TGFβ antibodies, which refer to any antibody capable of binding to each of the TGFβ isoforms, i.e., TGFβ1, TGFβ2, and TGFβ3. In some embodiments, the pan-TGFβ antibody binds and neutralizes the activity of all three isoforms, i.e., TGFβ1, TGFβ2, and TGFβ3 activity.

[0108] efficacy:The term "efficacy" as used herein refers to the activity of a drug, such as a functional antibody (or fragment) with inhibitory activity, in relation to the concentration or amount of drug that produces a given effect. For example, an antibody that can produce a specific effect at a given dosage is more potent than another antibody that requires twice the amount (dosage) to produce the same effect. Efficacy can be measured in a cell-based assay, such as a TGFβ activation / inhibition assay. In some cases, the degree of TGFβ activation, such as activation triggered by integrin binding, can be measured in a cell-based system in the presence or absence of a test item (e.g., an inhibitory antibody). Typically, antibodies with higher affinity tend to exhibit higher efficacy than antibodies with lower affinity.

[0109] Presenting molecules: Presentation molecules are proteins that form covalent bonds with latent proproteins (e.g., proTGFβ1) and "present" the inactive complex in an extracellular niche (e.g., the ECM or the surface of immune cells), thereby maintaining its latency until an activation event occurs. Known presentation molecules for proTGFβ1 include LTBP1, LTBP3, GARP, and LRRC33, which can form presentation molecule-proTGFβ1 complexes, i.e., LTBP1-proTGFβ1, LTBP3-proTGFβ1, GARP-proTGFβ1, and LRRC33-proTGFβ1, respectively. LTBP1 and LTBP3 are components of the extracellular matrix (ECM); therefore, LTBP1-proTGFβ1 and LTBP3-proTGFβ1 can be collectively referred to as "ECM-associated" (or "matrix-associated") proTGFβ1 complexes, which mediate ECM-associated TGFβ1 signaling / activity. On the other hand, GARP and LRRC33 are transmembrane proteins expressed on the cell surface of certain cells; therefore, GARP-proTGFβ1 and LRRC33-proTGFβ1 can be collectively referred to as the "cell-associated" (or "cell surface") proTGFβ1 complex, which mediates cell-associated (e.g., immune cell-associated) TGFβ1 signaling / activity.

[0110] ProTGFβ1: The term "proTGFβ1" as used herein is intended to encompass the precursor form of the inactive TGFβ1 complex, which contains the prodomain sequence of TGFβ1 within the complex. Thus, the term may include the pro-form of TGFβ1 as well as the latent form. The expression "pro / latent TGFβ1" may be used interchangeably. The "pro" form of TGFβ1 exists prior to proteolytic cleavage at the furin site. Upon cleavage, the resulting form is said to be the "latent" form of TGFβ1. The "latent" complex remains associated until further activation, e.g., triggered by an integrin-driven activation event. The proTGFβ1 complex is composed of dimeric TGFβ1 proprotein polypeptides linked by disulfide bonds. The latent dimeric complex is covalently linked to a single presentation molecule via the cysteine ​​residue at position 4 (Cys4) of each proTGFβ1 polypeptide. The adjective "latent" can generally be used to describe the "inactive" state of TGFβ1, prior to an integrin-mediated or other activation event. The proTGFβ1 polypeptide contains a prodomain (LAP) and a growth factor domain (SEQ ID NO: 12).

[0111] Regulatory T cells (Tregs):"Regulatory T cells," or Tregs, are a type of immune cell characterized by the expression of biomarkers CD4, forkhead box P3 (FOXP3), CD25, and STAT5. Tregs, often referred to as regulatory T cells, represent a subpopulation of T cells that regulate the immune system, maintain tolerance to self-antigens, and prevent autoimmune diseases. Tregs are immunosuppressive and generally suppress or downregulate the induction and proliferation of effector T (Teff) cells. Tregs can develop in the thymus (so-called CD4+Foxp3+ "natural" Tregs) or differentiate in the periphery upon priming of naive CD4+ T cells by antigen-presenting cells (APCs), for example, after exposure to TGFβ or retinoic acid. Treg cells produce and secrete cytokines, including IL-10 and TGFβ1. In general, the differentiation of Tregs and Th17 cells is negatively correlated.

[0112] Specific binding: As used herein, the terms "specific binding" or "specifically binds" mean that the interaction of an antibody, or antigen-binding portion thereof, with an antigen is dependent on the presence of a particular structure (e.g., an antigenic determinant or epitope). For example, an antibody, or antigen-binding portion thereof, binds to a specific protein rather than proteins in general. In some embodiments, an antibody, or antigen-binding portion thereof, binds to a target at least about 10 -6 K of M D More preferably, the measured K of such an antibody D The measured K value of such an antibody is preferably in the range of 10 to 100 nM. D The value ranges from 0.1 to 10 nM.

[0113] subject:The term "subject" in the context of therapeutic applications refers to an individual receiving clinical care or intervention, e.g., treatment, diagnosis, etc. Suitable subjects include vertebrates, including, but not limited to, mammals (e.g., humans and non-human mammals). When the subject is a human subject, the term "patient" may be used interchangeably. In a clinical context, the term "patient population" or "patient subpopulation" is used to refer to a group of individuals that meet a set of criteria, such as clinical criteria (e.g., disease presentations, disease stage, susceptibility to a particular condition, responsiveness to therapy, etc.), medical history, health status, sex, age group, genetic criteria (e.g., carriers of particular mutations, polymorphisms, gene duplications, DNA sequence repeats, etc.), and lifestyle factors (e.g., smoking, alcohol consumption, exercise, etc.).

[0114] TGFβ inhibitors: The term "TGFβ inhibitor" refers to any agent capable of antagonizing the biological activity or function of a TGFβ growth factor (e.g., TGFβ1, TGFβ2, and / or TGFβ3). The term is not intended to be limited by its mechanism of action and includes, for example, neutralizing inhibitors of TGFβ, receptor antagonists, soluble ligand traps, and activation inhibitors.

[0115] T helper 17 cells: T helper 17 cells (Th17) are a subset of pro-inflammatory helper T cells characterized by the markers STAT3 and RORγt and the production of cytokines including interleukin-17 (IL-17A / F) and IL-22. Th17 cells differentiate when naive T cells are exposed to TGFβ and IL-6. Th17 cells are generally associated with tissue inflammation, autoimmunity, and clearance of certain pathogens. The differentiation of Th17 and Treg cells is generally inversely related. An imbalance in the Th17 to Treg ratio (e.g., "Th17 / Treg") has been implicated in multiple pathologies, such as fibrotic and autoimmune conditions.

[0116] Th17 / Treg ratio:The Th17 to Treg ratio refers to the measured ratio (relative proportion) of the number of Th17 cells to the number of Treg cells in a tissue or sample of interest. Typically, known cell markers are used to identify, classify, or isolate cell types. Such markers include cell surface molecules expressed on specific cell types; cytokines or cytokine panels produced (e.g., secreted) by specific cell types; and / or mRNA expression of specific gene markers that serve as a signature / profile of a specific cell type. For example, a Th17 / Treg ratio of 1 means that there are equal or equivalent numbers of each cell type in the tissue or sample being evaluated. A Th17 / Treg ratio of 2 means that there are approximately twice as many Th17 cells as Treg cells in the tissue or sample. A high Th17 / Treg ratio can be caused by an increase in the number of Th17 cells, a decrease in the number of Treg cells, or a combination thereof.

[0117] Therapeutic concentration range: The term "therapeutic window" refers to the range of doses / concentrations that produce a therapeutic response in a subject without causing significant / observable / unacceptable side effects (e.g., within acceptable or tolerable side effects). The therapeutic window can be calculated as the ratio between the minimum effective concentration (MEC) and the minimum toxic concentration (MTC). To illustrate, a TGFβ1 inhibitor that achieves in vivo efficacy at 10 mg / kg and exhibits tolerable or acceptable toxicity at 100 mg / kg provides a therapeutic window of at least 10-fold (e.g., 10×). In contrast, a pan-inhibitor of TGFβ that is effective at 10 mg / kg but produces side effects at 5 mg / kg is said to have "dose-limiting toxicity." For example, applicants have found in preclinical models, such as rats, that context-independent TGFβ1 inhibitor antibodies are effective at dosages ranging from about <3 to 30 mg / kg / week and show no observable toxicity associated with pan-inhibition of TGFβ at at least 100 mg / kg / week for 4 weeks. On this basis, the context-independent TGFβ1 inhibitor antibody exhibits a minimum 3.3-fold and a maximum 33-fold therapeutic window.

[0118] toxicity: As used herein, the term "toxicity" refers to unwanted in vivo effects in a patient associated with a therapy administered to the patient, such as unwanted side effects and adverse events. "Tolerability" refers to the level of toxicity associated with a therapy or therapeutic regimen that a patient can reasonably tolerate without discontinuing the therapy due to toxicity (i.e., an acceptable level of toxicity). Typically, toxicity / toxicology testing is performed in one or more preclinical models prior to clinical development to evaluate the safety profile of a drug candidate (e.g., a monoclonal antibody therapy). Toxicity / toxicology testing can help determine the "no observed adverse effect level (NOAEL)" and "maximum maximal dose (MTD)" of a test item based on which a therapeutic concentration range can be estimated. Preferably, a species shown to be sensitive to a particular intervention should be selected as the preclinical animal model in which safety / toxicity testing is performed. In the case of TGFβ inhibition, suitable species include rats, dogs, and cynomolgus monkeys (cynos). Mice have been reported to be less sensitive to pharmacological inhibition of TGFβ and may not reveal toxicities that are potentially dangerous in other species, including humans, although certain studies have reported toxicities observed with pan-inhibition of TGFβ in mice. To illustrate, the NOAEL for a context-independent TGFβ1 inhibitor antibody in rats was the highest dose evaluated (100 mg / kg) based on a 4-week toxicology study, suggesting an MTD of >100 mg / kg per week.

[0119] Treat / treatment:The term "treat" or "treatment" includes therapeutic treatment, prophylactic treatment, and applications that reduce a subject's risk of developing a disorder or other risk factors. Thus, the term is intended broadly to mean causing a therapeutic benefit in a patient, for example, by enhancing or boosting the body's immunity; reducing or reversing immunosuppression; reducing, removing, or eradicating harmful cells or substances from the body; reducing disease burden (e.g., tumor burden); preventing recurrence or relapse; extending refractory periods; and / or otherwise improving survival. Treatment does not require a complete cure of the disorder, but encompasses embodiments that reduce symptoms or underlying risk factors. In the context of combination therapy, the term may refer to i) the ability of the second therapy to reduce the effective dosage of the first therapy, thereby reducing side effects and increasing tolerability; ii) the ability of the second therapy to make the patient more responsive to the first therapy; and / or iii) the ability to achieve additive or synergistic clinical benefits.

[0120] Variable region: The term "variable region" or "variable domain" refers to the portion of an antibody light and / or heavy chain, typically comprising approximately the amino-terminal 120-130 amino acids in the heavy chain and about the amino-terminal 100-110 amino acids in the light chain. In certain embodiments, the variable regions of different antibodies differ extensively in amino acid sequence, even among antibodies of the same species. The variable regions of an antibody typically determine the specificity of a particular antibody for its target.

[0121] TGFβ1 In mammals, the transforming growth factor-β (TGFβ) superfamily consists of at least 33 gene products. These include bone morphogenetic proteins (BMPs), activins, growth and differentiation factors (GDFs), and three isoforms of the TGFβ family: TGFβ1, TGFβ2, and TGFβ3. TGFβs are thought to play important roles in various processes, such as inhibition of cell proliferation, extracellular matrix (ECM) remodeling, and immune homeostasis. The importance of TGFβ1 for T cell homeostasis is illustrated by the observation that TGFβ1- / - mice live only 3-4 weeks and die of multiple organ failure due to strong immune activation (Kulkarni, AB, et al., Proc Natl Acad Sci USA, 1993. 90(2):770-4; Shull, MM, et al., Nature, 1992. 359(6397):693-9). The roles of TGFβ2 and TGFβ3 are less clear. Although the three TGFβ isoforms have distinct temporal and spatial expression patterns, they signal through the same receptors, TGFβRI and TGFβRII; however, in some cases, for example, for TGFβ2 signaling, type III receptors such as betaglycan are also required (Feng, X. Hand and R. Derynck, Annu Rev Cell Dev Biol, 2005. 21: pp. 659-93; Massague, J., Annu Rev Biochem, 1998. 67: pp. 753-91). Ligand-induced oligomerization of TGFβRI / II triggers phosphorylation of SMAD transcription factors, resulting in the transcription of target genes such as Col1a1, Col3a1, ACTA2, and SERPINE1 (Massague, J., J. Seoane, and D. Wotton, Genes Dev, 2005. 19(23): p. 2783-810).SMAD-independent TGFβ signaling pathways have also been described, for example, in cancers or aortic lesions in Marfan mice (Derynck, R. and YE Zhang, Nature, 2003. 425(6958): p. 577-84; Holm, TM, et al., Science, 2011. 332(6027): p. 358-61).

[0122] The biological importance of the TGF-β pathway in humans has been confirmed by genetic diseases. Camurati-Engelman disease results from an autosomal dominant mutation in the TGFB1 gene, resulting in dysplastic bone formation and constitutive activation of TGF-β1 signaling (Janssens, K., et al., J Med Genet, 2006. 43(1): pp. 1-11). Patients with Loeys / Dietz syndrome carry autosomal dominant mutations in components of the TGF-β signaling pathway, resulting in aortic aneurysms, sequestration, and a bifid uvula (VanLaer, L., H. Dietz, and B. Loeys, Adv Exp Med Biol, 2014. 802: pp. 95-105). Because TGF-β pathway dysregulation is involved in multiple diseases, several drugs targeting the TGF-β pathway have been developed and tested in patients, but with limited success. Most TGFβ inhibitors described to date lack isoform specificity, as briefly summarized below.

[0123] Fresolimumab, a humanized monoclonal antibody that binds to and inhibits all three isoforms of TGF-β, is being clinically tested in patients with focal segmental glomerulosclerosis, malignant melanoma, renal cell carcinoma, and systemic sclerosis (Rice, LM, et al., J Clin Invest, 2015. 125(7): pp. 2795-807; Trachtman, H., et al., Kidney Int, 2011. 79(11): pp. 1236-43; Morris, JC, et al., PLoS One, 2014. 9(3): pp. e90353). Additional companies have developed monoclonal antibodies against TGF-β growth factors with varying degrees of selectivity for TGF-β isoforms. Such agents may induce toxicity in vivo through residual activity against other TGF-β family members besides TGF-β1. This lack of isoform specificity may be due to the high degree of sequence identity between the isoforms.

[0124] Other approaches to targeting the TGFβ pathway include ACE-1332, a soluble TGFβRII-Fc ligand trap from Acceleron (Yung, LM, et al., Am J Respir Crit Care Med, 2016. 194(9): pp. 1140-1151), or small molecule inhibitors of the ALK5 kinase, such as Eli Lilly's galunisertib. ACE-1332 binds TGFβ1 and TGFβ3 with equally high affinity (Yung, LM, et al., Am J Respir Crit Care Med, 2016. 194(9): pp. 1140-1151), and ALK5 inhibitors block the activity of all growth factors that signal through TGFR1. Substantial toxicity has been found in preclinical studies using ALK5 inhibitors (Anderton, MJ, et al., Toxicol Pathol, 2011.39(6):p.916-24; Stauber, A., et al., Clinical Toxicology, 2014.4(3):p.1-10), and sophisticated clinical dosing schemes are required to maintain efficacy while reducing adverse events (Herbertz, S., et al., Drug Des Devel Ther, 2015.9:p.4479-99). In fact, the issue of TGFβ signaling specificity and its possible effect on the toxicity observed with known TGFβ inhibitors has not been raised in most, if not all, candidate drugs that attempt to block TGFβ. For example, how much toxicity is attributable to the inhibition of TGFβ1 versus TGFβ2 and / or TGFβ3 has not been addressed. Similarly, models of TGFβ activation have not been considered in the design or development of methods to antagonize TGFβ signaling.

[0125] Recent structural insights into the activation mechanism of TGFβ1 (Shi, M., et al., Nature, 2011. 474(7351):pp. 343-9) have enabled more specific approaches to TGFβ inhibition (see, e.g., PCT / US2017 / 21972, the entire contents of which are incorporated herein by reference). Unlike other cytokines, TGFβ superfamily members are not secreted as active growth factors, but as dimeric proproteins consisting of an N-terminal prodomain and a C-terminal growth factor domain. Cleavage of proTGFβ1 by furin protease separates the homodimeric growth factor domain from its prodomain (also called latency-associated peptide (LAP)). However, the growth factor and LAP remain noncovalently associated, forming a latent complex that cannot bind to its receptor and induce signaling. During translation, latent TGFβ1 (also called small latent complex (SLC)) is linked to a "presentation molecule" via disulfide bridges to form a large latent complex (LLC). These molecules enable proTGFβ1 to be presented in specific cellular or tissue contexts. Two cysteines near the N-terminus of latent TGFβ1 are linked to cysteines at appropriate positions on the presentation molecule. The identity of the presentation molecule depends on the environment and cell type producing latent TGFβ1. For example, fibroblasts secrete latent TGFβ1 tethered to latent TGFβ-binding protein (LTBP), which associates with proteins in the extracellular matrix (ECM) (i.e., fibronectin, fibrillin-1), binding latent TGFβ to the ECM (Robertson et al., Matrix Biol 47:44-53 (2015) (Figure 2A)).On the surface of activated regulatory T cells, latent TGF-β1 is covalently bound to the transmembrane protein GARP (glycoprotein A repeat-dominant protein (GARP)). A protein closely related to GARP, LRRC33 (leucine-rich repeat-containing protein 33), serves as a presentation molecule for TGF-β1 on the surface of monocytes, macrophages, and microglia (Wang, R., et al., Mol Biol Cell, 2012. 23(6): pp. 1129-39, and Springer, Int. BMP Conference 2016).

[0126] Several studies have shed light on the mechanism of TGF-β1 activation. Three integrins, αVβ6, αVβ8, and αVβ1, have been shown to be key activators of latent TGF-β1 (Reed, NI, et al., Sci Trans lMed, 2015.7(288):p.288ra79; Travis, MA and D. Sheppard, Annu Rev Immunol, 2014.32:p.51-82; Munger, JS, et al., Cell, 1999.96(3):p.319-28). αV integrins bind with high affinity to the RGD sequence present in TGF-β1 and TGF-β1 LAP (Dong, X., et al., Nat Struct Mol Biol, 2014.21(12):p.1091-6). Transgenic mice with a mutation within the TGFβ1 RGD site that prevents integrin binding but not secretion phenocopy the TGFβ1- / - mouse phenotype (Yang, Z., et al., J Cell Biol, 2007. 176(6): pp. 787-93). Mice lacking both β6 and β8 integrins recapitulate all essential phenotypes of TGFβ1 and TGFβ3 knockout mice, including multiorgan inflammation and cleft palate, confirming the essential role of these two integrins for TGFβ1 activation in development and homeostasis (Aluwihare, P., et al., J Cell Sci, 2009. 122(Pt2): pp. 227-32). What is crucial for the integrin-dependent activation of latent TGFβ1 is the covalent binding to the presenting molecule; disruption of the disulfide bond between GARP and TGFβ1 LAP by mutagenesis does not impair complex formation but completely abolishes TGFβ1 activation by αVβ6 (Wang, R., et al., Mol Biol Cell, 2012.23(6):p.1129-39).Recent structures of latent TGF-β1 have revealed how integrins enable the release of active TGF-β1 from the latent complex: covalent binding of latent TGF-β1 to its presentation molecule anchors it to the ECM via LTBP or to the cytoskeleton via GARP or LRRC33. Integrin binding to the RGD sequence induces a force-dependent change in the structure of LAP, allowing active TGF-β1 to be released and bind to nearby receptors (Shi, M., et al., Nature, 2011. 474(7351):pp.343-9). The importance of integrin-dependent TGF-β1 activation in disease has also been well documented. Small molecule inhibitors of αVβ1 protect against bleomycin-induced pulmonary fibrosis and carbon tetrachloride-induced liver fibrosis (Reed, NI, et al., Sci Transl Med, 2015.7(288):p.288ra79), and antibody-mediated blockade of αVβ6 or loss of integrin β6 expression suppresses bleomycin-induced pulmonary fibrosis and radiation-induced fibrosis (Munger, JS, et al., Cell, 1999.96(3):p.319-28; Horan, GS, et al., Am J Respir Crit Care Med, 2008.177(1):p.56-65). In addition to integrins, other mechanisms of TGFβ1 activation have been demonstrated, including activation by thrombospondin-1 and proteases such as matrix metalloproteinases (MMPs), cathepsin D, or kallikrein. However, most of these studies have been performed in vitro using purified proteins, and there is less evidence for the role of these molecules from in vivo studies. Knockout of thrombospondin-1 recapitulates some aspects of the TGFβ1- / - phenotype in some tissues, but does not protect against bleomycin-induced pulmonary fibrosis, which is known to be TGFβ-dependent (Ezzie, ME, et al., Am J Respir Cell Mol Biol, 2011. 44(4): p. 556-61).Furthermore, knockout of candidate proteases did not result in a TGFβ1 phenotype (Worthington, JJ, JE Klementowicz, and MA Travis, Trends Biochem Sci, 2011. 36(1): p. 47-54), which could be explained by redundancies or the importance of these mechanisms in specific diseases rather than in development and homeostasis.

[0127] TGFβs are involved in multiple biological processes, including fibrosis, immune regulation, and cancer progression. TGFβ1 was the first identified member of the TGFβ superfamily of proteins. Like other members of the TGFβ superfamily, TGFβ1 and the isoforms TGFβ2 and TGFβ3 are initially expressed as inactive precursor proprotein forms (termed proTGFβ). TGFβ proteins (e.g., TGFβ1, TGFβ2, and TGFβ3) are proteolytically cleaved by proprotein convertases (e.g., furin) to produce latent forms (termed latent TGFβ). In some embodiments, the proprotein or latent forms of TGFβ proteins (e.g., TGFβ1, TGFβ2, and TGFβ3) may be referred to as "pro / latent TGFβ proteins." TGFβ1 can be presented relative to other molecules in complexes with multiple molecules, including, for example, GARP (forming a GARP-TGFβ1 complex), LRRC33 (forming a LRRC33-TGFβ1 complex), LTBP1 (forming a LTBP1-TGFβ1 complex), and / or LTBP3 (forming a LTBP3-TGFβ1 complex). The TGFβ1 present in these complexes can be either in a latent form (latent TGFβ1) or a precursor form (proTGFβ1).

[0128] Isoform selectivity and mechanism of action of TGF inhibitors From a safety perspective, it is increasingly recognized that broad inhibition of TGFβ across isoforms may be responsible for observed toxicities, highlighting the lack of success in developing TGFβ inhibitors to date. To avoid potentially dangerous side effects, several groups have recently turned to identifying inhibitors that target a subset, but not all, of the isoforms and maintain efficacy. However, from an efficacy perspective, conventional wisdom in the field holds that inhibiting multiple TGFβ isoforms is advantageous to achieve therapeutic efficacy. To accommodate this, toxicity management through "careful dosing regimens" has been suggested as a solution (Brennan et al. (2018) mAbs, 10:1, 1-17). Consistent with this premise, numerous groups are developing TGFβ inhibitors that target more than one isoform. These include small molecular weight antagonists of TGFβ receptors, e.g., ALK5 antagonists, such as galunisertib (LY2157299 monohydrate); monoclonal antibodies (e.g., neutralizing antibodies) that inhibit all three isoforms ("pan-inhibitor" antibodies) (see, e.g., WO2018 / 134681); monoclonal antibodies that preferentially inhibit two of the three isoforms, such as antibodies against TGFβ1 / 2 (e.g., WO2016 / 161410) and TGFβ1 / 3 (e.g., WO2006 / 116002); and engineered molecules (e.g., fusion proteins). Examples of antibodies that selectively bind and neutralize both TGFβ1 and TGFβ2 include XOMA089 (or NIS793) and variants thereof (see, e.g., WO2016 / 161410).

[0129] Previously, we demonstrated that inhibition of TGFβ1 alone is sufficient to sensitize immunosuppressive tumors to checkpoint inhibitor therapy, even in tumors in which both TGFβ1 and TGFβ3 are co-expressed (PCT / US2019 / 041373). Similarly, TGFβ1-selective inhibitors have been shown to attenuate fibrosis in preclinical models, including a mouse liver fibrosis model in which both TGFβ1 and TGFβ3 isoforms are co-expressed within fibrotic tissue, even in separate cell types, as observed by immunohistochemistry (data not shown). Surprisingly, inhibition of TGFβ3 promoted a fibrosis-promoting phenotype. Exacerbation of fibrosis was observed when TGFβ3 inhibitors were used alone. Furthermore, when used in combination with a TGFβ1-selective inhibitor, a TGFβ3 inhibitor attenuated the anti-fibrotic effect of the TGFβ1-selective inhibitor, as evidenced by increased collagen accumulation in fibrotic liver. These results raise the possibility that inhibitory efficacy against TGFβ3 may be an undesirable property of TGFβ inhibitors for use as therapy in settings where fibrosis is a concern.

[0130] Because fibrosis-promoting phenotypes (e.g., increased collagen deposition within the ECM) are associated not only with fibrosis but also with aspects of cancer progression, such as tumor invasion and metastasis, there is broader implications for this unexpected finding beyond the context of fibrosis. See, for example, Chakravarthy et al. (Nature Communications, (2018) 9:4692, "TGF-β-associated extracellular matrix genes link cancer-associated fibroblasts to immune evasion and immunotherapy failure"). Diseased tissues with dysregulated ECM, including the fibrotic tissue and stroma of various tumor types, can express both TGFβ1 and TGFβ3. Currently, multiple groups are attempting to develop TGFβ inhibitors that target both of these isoforms, such as ligand traps, neutralizing antibodies, and integrin inhibitors. However, the findings presented herein caution that such approaches may actually exacerbate (e.g., worsen) the disease.

[0131] Thus, the present disclosure provides the teaching that for the treatment of disorders involving ECM dysregulation, such as fibrosis and cancer, a TGFβ inhibitor that does not specifically target TGFβ3 should be selected. Preferably, such an inhibitor is an isoform-selective inhibitor of TGFβ1, such as an inhibitor that selectively targets LTBP1 / 3-associated TGFβ1 (e.g., as disclosed herein). Related methods include methods for selecting TGFβ inhibitors for use in treating a fibrotic disorder in a subject, the methods including testing the efficacy of one or more candidate inhibitors for their ability to inhibit TGFβ1, TGFβ2, and TGFβ3, and selecting an inhibitor that inhibits TGFβ1 but not TGFβ3 for therapeutic use. Related treatment methods may further include administering to a subject an inhibitor that inhibits TGFβ1 but not TGFβ3 in an amount sufficient to treat the fibrotic disorder or to treat a subject having or at risk of developing a fibrotic disorder. Preferably, the selected inhibitor is an antibody or fragment thereof (e.g., as disclosed herein) that selectively inhibits LTBP1 and / or LTBP3-associated TGFβ1 signaling. In some embodiments, subjects at risk of developing fibrotic disorders may suffer from metabolic disorders such as diabetes, obesity, and NASH. The proposed exclusion of patient subpopulations aims to reduce the risk of triggering, promoting, or exacerbating fibrosis-promoting effects.

[0132] In addition to the potential concerns about inhibiting TGFβ3 addressed above, Takahashi et al. (Nat Metab. 2019, 1(2):291-303) recently reported a beneficial role for TGFβ2 in metabolic regulation. The authors identified TGFβ2 as an exercise-induced adipokine that stimulates glucose and fatty acid uptake in vitro and tissue glucose uptake in vivo; improves metabolism in obese mice; and reduces inflammation induced by a high-fat diet. Furthermore, the authors observed that lactate, a metabolic product released from muscle during exercise, stimulates TGFβ2 expression in human adipocytes, and that lactate-lowering agents reduce circulating TGFβ2 levels and diminish the improvement in glucose tolerance stimulated by exercise. These observations suggest that the therapeutic use of TGFβ inhibitors with inhibitory activity against the TGFβ2 isoform may be harmful, at least in metabolic terms.

[0133] Without being bound by any particular theory, it is believed to be advantageous to select a TGFβ1-selective inhibitor as a TGFβ inhibitor for use in the treatment of metabolic diseases, such as liver fibrosis associated with NASH. In a preferred embodiment, the TGFβ1-selective inhibitor selected for use in the treatment of metabolic diseases, such as the antibodies and fragments disclosed herein, selectively inhibits LTBP1 / 3-associated TGFβ1. Thus, the present invention includes a TGFβ inhibitor for use in the treatment of metabolic diseases in a subject, wherein the treatment involves selecting a TGFβ inhibitor that inhibits TGFβ1 but not TGFβ2 (wherein the inhibitor may be TGFβ1-selective) and administering the inhibitor to a subject suffering from a metabolic disease. The metabolic disease may be a liver disease, such as liver fibrosis, NASH, or NAFLD, and may be associated with obesity and / or type 2 diabetes. In a preferred embodiment, the TGFβ1 selective inhibitor is an antibody or antigen-binding fragment thereof that selectively targets matrix-associated TGFβ1 (e.g., LTBP1-proTGFβ1 and LTBP3-proTGFβ1), such as those disclosed herein.

[0134] In a preferred embodiment, TGFβ inhibitors for use in treating fibrotic disorders are isoform-selective activation inhibitors of TGFβ1 (e.g., low kTGFβ1 inhibitors as disclosed herein) capable of targeting latent complexes containing matrix-associated TGFβ1 in vivo. OFF or long t 1 / 2 It is a novel antibody having the following structure:

[0135] The antibodies of the present disclosure act by preventing a step in TGFβ1 activation. In some embodiments, such inhibitors can inhibit integrin-dependent (e.g., mechanical or force-driven) activation of TGFβ1. In some embodiments, such inhibitors can inhibit protease-dependent or protease-induced TGFβ1 activation. The latter includes inhibitors that inhibit TGFβ1 activation steps in an integrin-independent manner. In some embodiments, such inhibitors can inhibit TGFβ1 activation regardless of the mode of activation, e.g., inhibit both integrin-dependent and protease-dependent activation of TGFβ1. Non-limiting examples of proteases that can activate TGFβ1 include serine proteases such as kallikrein, chymotrypsin, trypsin, elastase, plasmin, thrombin, and zinc metalloproteases (MMP family) such as MMP-2, MMP-9, MMP-12, MMP-13, and ADAM proteases (e.g., ADAM10 and ADAM17). Kallikreins include plasma kallikrein and tissue kallikrein, such as KLK1, KLK2, KLK3, KLK4, KLK5, KLK6, KLK7, KLK8, KLK9, KLK10, KLK11, KLK12, KLK13, KLK14, and KLK15.

[0136] Latent TGFβ-binding protein (LTBP) There are four known LTBPs in mammals, LTBP1 to LTBP4, each with multiple splice variants (Robertson, I.B., et al., Matrix Biol, 2015.47:44-53). LTBP2 is the only LTBP that does not associate with latent TGFβ (Saharinen, J. and J. Keski-Oja, Mol Biol Cell, 2000.11(8):2691-704). While the association between LTBP1 or LTBP3 and latent TGFβ1 is well established, the role of LTBP4 in TGFβ presentation is less clear. The complex between LTBP4 and latent TGFβ1 is thought to form even less efficiently, potentially due to the absence of several negatively charged residues in the TGFβ-binding domain of LTBP4 (Saharinen, J. and J. Keski-Oja, Mol Biol Cell, 2000. 11(8): p. 2691-704; Chen, Y., et al., J Mol Biol, 2005. 345(1): p. 175-86). Both LTBP4S- / - mice and Urban-Rifkin-Davis syndrome patients with null mutations in LTBP4 suffer from disrupted elastic fiber assembly (Urban, Z., et al., Am J Hum Genet, 2009, 85(5):p.593-605; Dabovic, B., et al., J Cell Physiol, 2015, 230(1):p.226-36). Furthermore, LTBP4S- / - mice have defects in pulmonary septation and elastic fiber formation, whereas transgenic mice with LTBP4 that cannot form a complex with latent TGF-β1 do not have an obvious phenotype (Dabovic, B., et al., J Cell Physiol, 2015, 230(1):p.226-36). It is unclear whether LTBP4 is directly involved in regulating latent TGFβ1 by functioning as a presentation molecule; instead, LTBP4 may be required for the proper formation of elastic fibrils in the ECM, and its loss indirectly affects latent TGFβ1 activation through defects in the ECM.

[0137] In one aspect, the invention relates to an inhibitor, e.g., an immunoglobulin, e.g., an antibody, or antigen-binding portion thereof, that selectively binds to a complex comprising a TGFβ proprotein and an LTBP protein (e.g., LTBP1 or LTBP3). In a preferred embodiment, the TGFβ protein is TGFβ1. In some embodiments, the binding molecules disclosed herein selectively bind to a complex comprising pro / latent TGFβ1 and LTBP1 or LTBP3. Such binding molecules may be able to selectively modulate TGFβ1 activity in a context-dependent manner, i.e., by modulating TGFβ1 in the context of the LTBP protein, without modulating the activity of TGFβ1 in complex with other presentation molecules (e.g., GARP and / or LRRC33).

[0138] Antibodies that selectively inhibit LTBP-mediated TGF-β activation The present invention provides novel TGFβ inhibitors that selectively target matrix- or ECM-associated TGFβ activity. More specifically, such inhibitors include isoform-specific, context-selective inhibitors of TGFβ1 activation that specifically bind to latent forms of TGFβ1 (e.g., proTGFβ1 complexes) within the ECM environment and prevent release of the mature growth factor from the complex in the niche. Such matrix-targeted inhibitors are context-specific in that they selectively bind to proTGFβ1 associated with ECM-presenting molecules (i.e., LTBP1 and / or LTBP3). Thus, disclosed herein are monoclonal antibodies and fragments thereof capable of binding to epitopes present in the LTBP1-proTGFβ1 complex and / or the LTBP3-proTGFβ1 complex, but which epitopes are not present in the GARP-proTGFβ1 complex and / or the LRRC33-proTGFβ1 complex.

[0139] In some embodiments, the context-selective inhibitors of the present disclosure bind to both the human LTBP1-proTGFβ1 complex and the human LTBP3-proTGFβ1 complex with an affinity (measured K D In a preferred embodiment, such an antibody is capable of specifically binding to both the human LTBP1-proTGFβ1 complex and human LTBP3-proTGFβ1 with an affinity (measured K ) of <5 nM, respectively, in a suitable in vitro binding assay such as Octet. D In contrast, these context-specific antibodies do not exhibit any detectable binding to the human GARP-proTGFβ1 complex or the human LRRC33-proTGFβ1 complex under identical assay conditions. Preferably, such antibodies or fragments bind to the human LTBP1-proTGFβ1 complex and the human LTBP3-proTGFβ1 complex, respectively, with a KD of less than 1 nM.

[0140] In some embodiments, the context-selective inhibitors of the present disclosure are capable of specifically binding to either the human LTBP1-proTGFβ1 complex or the human LTBP3-proTGFβ1 complex, neither of which exhibits any detectable binding to the human GARP-proTGFβ1 complex or the human LRRC33-proTGFβ1 complex under identical assay conditions.

[0141] The art is familiar with suitable in vitro binding assays, including, for example, BLI-based assays such as Octet and SPR-based assays such as Biacore, which can be used to measure antibody-antigen interactions (e.g., binding kinetics). As used herein, "no binding" in these contexts can refer to the absence of detectable binding by a particular assay, e.g., any binding that is below the sensitivity of the assay. In some embodiments, "no binding" can refer to "no meaningful binding" established by a cutoff that defines the minimum level required to be considered meaningful when measured by a particular assay system. For example, in a BLI (Octet) assay, an optical shift of 0.1 nm measured at a given analyte (e.g., target antigen) concentration (e.g., 100 nM, 200 nM, etc.) can indicate meaningful binding, below which no binding can be considered (see, e.g., Example 9). Similarly, in a typical SPR (Biacore) assay, the cutoff level can be 0.2 RU (resonance units). In some embodiments, the signal at 0 nM antibody (e.g., background noise) is subtracted from all sensorgrams obtained at higher concentrations. Under these conditions using SPR (Biacore), 0.2 RU may be an appropriate cutoff.

[0142] In some embodiments, the context-selective inhibitors of the present disclosure are capable of specifically binding to the human LTBP1-proTGFβ1 complex or the human LTBP3-proTGFβ1 complex and do not exhibit detectable binding to the human GARP-proTGFβ1 complex as measured by BLI under the same assay conditions used to measure binding to the human LTBP1-proTGFβ1 complex and / or human LTBP3-TGFβ1.

[0143] In some embodiments, the context-selective inhibitors of the present disclosure exhibit a K Dat least 50-fold lower (e.g., at least 75-fold lower, at least 100-fold lower) than D In some embodiments, K D is determined by BLI or SPR. D is determined by SPR.

[0144] In some embodiments, the context-selective inhibitors of the present disclosure are capable of specifically binding to the human LTBP1-proTGFβ1 complex or the human LTBP3-proTGFβ1 complex and do not exhibit detectable binding to the LRRC33-proTGFβ1 latent complex as measured by BLI under the same assay conditions used to measure binding to the human LTBP1-proTGFβ1 complex and / or human LTBP3-TGFβ1.

[0145] In some embodiments, the context-selective inhibitors of the present disclosure exhibit a K D at least 50-fold lower (e.g., at least 75-fold lower, at least 100-fold lower) than D In some embodiments, K D is determined by BLI or SPR. D is determined by SPR.

[0146] The present invention encompasses the recognition that preferred antibodies (e.g., immunoglobulins and antigen-binding fragments, e.g., Fabs, and engineered constructs incorporating such fragments) slowly dissociate from their target / antigen (e.g., human LTBP1-proTGFβ1, human LTBP3-TGFβ1) upon binding to the antigen. Thus, the novel antibodies of the present invention are selected not only for their high overall affinity (e.g., KD within 5 nM), but also for their particularly low dissociation rates. According to the present disclosure, such antibodies have a KD of ≦5×10 as measured by BLI. -4 (1 / s) (e.g., when binding to human LTBP1-proTGFβ1 and / or human LTBP3-TGFβ1). -4 The dissociation rate (1 / s) can be a monovalent dissociation rate or a bivalent dissociation rate. In some embodiments, the antibody or fragment has a monovalent dissociation half-life (t) of at least 45 minutes (e.g., ≥ 45, 60, 75, 90 minutes) as measured by SPR. 1 / 2 ) and slowly dissociates from human LTBP1-proTGFβ1 and / or human LTBP3-TGFβ1, preferably with respect to both human LTBP1-proTGFβ1 and human LTBP3-TGFβ1. On the other hand, if binding to human GARP-proTGFβ1 and / or LRRC33-TGFβ1 complexes is detectable, such antibodies rapidly dissociate from human GARP-proTGFβ1 and / or human LRRC33-TGFβ1 complex(es), particularly human GARP-proTGFβ1. In some embodiments, the antibody has a t of less than 5 minutes as measured by SPR. 1 / 2 In particularly preferred embodiments, the antibodies or fragments exhibit species cross-reactivity and therefore bind to their murine counterparts with comparable affinity.

[0147] The TGFβ1 present in these complexes may be in either a latent form (latent TGFβ1) or a precursor form (proTGFβ1). In one embodiment, the inhibitor does not significantly bind to LTBP1 alone (e.g., when not complexed with TGFβ1). In another embodiment, the inhibitor does not significantly bind to LTBP3 alone (e.g., when not complexed with TGFβ1). In another embodiment, the inhibitor does not significantly bind to TGFβ1 alone (e.g., pro- or latent TGFβ1 not complexed with LTBP1 or LTBP3, or mature TGFβ1). In another embodiment, an inhibitor that selectively binds to the LTBP1-TGFβ1 complex and / or the LTBP3-TGFβ1 complex does not significantly bind to complexes containing TGFβ1 and other presentation molecules, such as the GARP-TGFβ1 complex (e.g., GARP complexed with pro- or latent TGFβ1) and / or the LRRC33-TGFβ1 complex (e.g., LRRC33 complexed with pro- or latent TGFβ1). In one embodiment, an inhibitor that selectively binds to LTBP1 / 3-TGFβ1 does not significantly bind to one or more (e.g., two or more, three or more, or all four) of the following: LTBP1 alone, TGFβ1 alone, the GARP-TGFβ1 complex, and the LRRC33-TGFβ1 complex. Additionally, in some embodiments, the inhibitor does not significantly bind to LTBP3 alone.

[0148] The term "inhibitor" as used herein refers to any agent capable of blocking or antagonizing TGFβ1 signaling. Such agents may include small molecule antagonists of TGFβ1 and biological antagonists of TGFβ1 (e.g., protein fragments and antibodies). In some embodiments, the inhibitor may be an antibody (fragment thereof, including, for example, domain antibodies (dAbs) as described in U.S. Patents 6,291,158; 6,582,915; 6,593,081; 6,172,197; and 6,696,245), a small molecule inhibitor, an adnectin, an affibody, a DARPin, an anticalin, an avimer, a versabody, or gene therapy. The use of inhibitors encompassed by the present invention also includes antibody mimetics, such as monobodies and single-domain antibodies. Monobodies are synthetic binding proteins that typically use the fibronectin type III domain (FN3) as a molecular scaffold. Monobodies include Adnectins™, which are based on the tenth fibronectin type III domain.

[0149] In some aspects, the inhibitor, e.g., an antibody, or antigen-binding portion thereof, selectively binds to an epitope present on the LTBP1 / 3-TGFβ1 complex that is not present on the GARP-TGFβ1 complex and / or the LRRC33-TGFβ1 complex. In some embodiments, the epitope is accessible due to a conformational change in LTBP1 / 3 and / or TGFβ1 that occurs when LTBP1 / 3 and TGFβ1 form a complex. In this embodiment, the epitope is not present in LTBP1 / 3 or TGFβ1 when the proteins are not associated in a complex. In one embodiment, the epitope is present on TGFβ1 when TGFβ1 is in a complex with LTBP1 or LTBP3. In another embodiment, the epitope is present on LTBP1 when LTBP1 is in a complex with TGFβ1. In another embodiment, the epitope is present on LTBP3 when LTBP3 is in a complex with TGFβ1. In another embodiment, the epitope comprises residues from both LTBP1 and TGFβ1.In another embodiment, the epitope comprises residues from both LTBP3 and TGFβ1.

[0150] Surprisingly, some of the LTBP1 / 3 complex-selective antibodies disclosed herein (e.g., Ab14, Ab20, Ab21-23, Ab17, and Ab24-29) are capable of binding to the small latent complex (proTGFβ1C4S) in the absence of a presenting molecule (e.g., LTBP1 / 3), still providing context selectivity. Without wishing to be bound by theory, this finding suggests that the antibodies (and their variants, or cross-competing antibodies) may bind to epitopes that are available in the LTBP1 / 3-proTGFβ1 complex and proTGFβ1 alone but are not available in the presence of an LRRC-type presenting molecule (GARP or LRRC33). The epitope may be entirely on latent TGFβ1 but is occluded (directly or indirectly) when GARP or LRRC33 is complexed.

[0151] Alternatively, LTBP-selective inhibitors of the present disclosure may bind to a combinatorial epitope comprising one or more amino acid residues of LTBP1 or LTBP3 and one or more amino acid residues of proTGFβ1, thereby conferring context selectivity for LTBP-bound complexes over GARP / LRRC33-bound complexes. In these embodiments, selectivity for the isoform (TGFβ1) as well as the context (ECM) can be attributed to the combined contributions from both elements of the antigen complex.

[0152] In some embodiments, the inhibitor, e.g., an antibody, or antigen-binding portion thereof, is selective for the TGFβ1 isoform. In such embodiments, the inhibitor, e.g., an antibody, or antigen-binding portion thereof, does not bind to TGFβ2 and / or TGFβ3. For example, in one embodiment, the inhibitor, e.g., an antibody, or antigen-binding portion thereof, selectively binds to the LTBP1 / 3-TGFβ1 complex but does not bind to TGFβ2 or complexes containing TGFβ2. In another embodiment, the inhibitor, e.g., an antibody, or antigen-binding portion thereof, selectively binds to the LTBP1 / 3-TGFβ1 complex but does not bind to TGFβ3 or complexes containing TGFβ3.

[0153] In some embodiments, the inhibitor, e.g., an antibody, or antigen-binding portion thereof, does not prevent TGFβ1 from binding to an integrin. For example, in some embodiments, the inhibitor, e.g., an antibody, or antigen-binding portion thereof, does not mask the integrin-binding site of TGFβ1.

[0154] In one aspect, the present disclosure provides functional inhibitors, e.g., antibodies, that modulate TGFβ1 activity. In exemplary embodiments, the antibodies described herein are inhibitory antibodies that inhibit the function or activity of TGFβ1. In some embodiments, the antibodies, or antigen-binding portions thereof, inhibit the activation (release) of TGFβ1 by the LTBP1-TGFβ1 complex and / or the LTBP3-TGFβ1 complex. In exemplary embodiments, the present disclosure provides "context-specific" or "context-selective" inhibitors of TGFβ1 activation. Such inhibitors can bind to the LTBP1 / 3-TGFβ1 complex and inhibit the activation of TGFβ1 presented by LTBP1 or LTBP3 without inhibiting the activation of TGFβ1 presented by GARP and / or LRRC33. Thus, in some embodiments, the antibodies, or antigen-binding portions thereof, described herein inhibit the release of mature TGFβ1 from LTBP1-TGFβ1 complexes and / or LTBP3-TGFβ1 complexes, but do not inhibit the release of mature TGFβ1 from GARP-TGFβ1 complexes and / or LRRC33-TGFβ1 complexes. Due to the differential localization of LTBP, GARP, and LRRC33, the context-specific inhibitors of TGFβ1 provided by the present invention can block specific subsets of TGFβ1 activity in vivo. In one embodiment, the context-specific antibodies provided herein that inhibit LTBP1 / 3-TGFβ1 but not GARP-TGFβ1 or LRRC33-TGFβ1 can be used to inhibit TGFβ1 localized in the extracellular matrix. In another embodiment, the context-specific antibodies can inhibit TGFβ1 without modulating TGFβ1-associated immune activity or responses. In another embodiment, context-specific antibodies can be used to inhibit TGFβ1 activity associated with the extracellular matrix without modulating TGFβ1 activity associated with hematopoietic cells. Thus, context-specific antibodies can be used to inhibit LTBP1 / 3-associated TGFβ1 activity in applications where TGFβ1 activation in the context of GARP and / or LRRC33 is undesirable, as described herein.

[0155] In some embodiments, TGFβ1 comprises a naturally occurring mammalian amino acid sequence. In some embodiments, TGFβ1 comprises a naturally occurring human amino acid sequence. In some embodiments, TGFβ1 comprises a human, monkey, rat, or mouse amino acid sequence.

[0156] In some embodiments, the antibodies described herein, or antigen-binding portions thereof, selectively bind to a complex comprising a TGFβ1 protein comprising the amino acid sequence set forth in SEQ ID NO: 9 and LTBP1 or LTBP3. In some embodiments, the antibodies described herein, or antigen-binding portions thereof, selectively bind to an LTBP1 / 3-TGFβ1 complex comprising a non-naturally occurring TGFβ1 amino acid sequence (otherwise referred to herein as non-naturally occurring TGFβ1). For example, the non-naturally occurring TGFβ1 may comprise one or more recombinantly produced mutations relative to the naturally occurring TGFβ1 amino acid sequence.

[0157] In some embodiments, the antibodies, or antigen-binding portions thereof, described herein do not bind to TGFβ2 and / or TGFβ3, or to protein complexes containing TGFβ2 and / or TGFβ3. Exemplary TGFβ2 and TGFβ3 amino acid sequences are set forth in SEQ ID NOs: 10 and 11, respectively. In some embodiments, the TGFβ1, TGFβ2, or TGFβ3 amino acid sequence comprises the amino acid sequence set forth in SEQ ID NOs: 12-23 shown in Table 1. In some embodiments, the TGFβ1 amino acid sequence comprises the amino acid sequence set forth in SEQ ID NOs: 24-31 shown in Table 2.

[0158] TGFβ1 LSTCKTIDMELVKRKRIEAIRGQILSKLRLASPPSQGEVPPGPLPEAVLALYNSTRDRVAGESAEPEPEPEADYYAKEVTRVLMVETHNEIYDKFKQSTHSIYMFFNTSELREAVPEPVLLSRAELRLLRLKLKVEQHVELYQKYSNNSWRYLSNRLLAPSDSPEWLSFDVTGVVRQWLSRGGEIEGFRLSAHCSCDSRDNTLQVDINGFTTGRRGDLATIHGMNRPFLLLMATPLERAQHLQSSRHRRALDTNYCFSSTEKNCCVRQLYIDFRKDLGWKWIHEPKGYHANFCLGPCPYIWSLDTQYSKVLALYNQHNPGASAAPCCVPQALEPLPIVYYVGRKPKVEQLSNMIVRSCKCS (SEQ ID NO: 9)

[0159] TGFβ2 SLSTCSTLDMDQFMRKRIEAIRGQILSKLKLTSPPEDYPEPEEVPPEVISIYNSTRDLLQEKASRRAAACERERSDEEYYAKEVYKIDMPPFFPSENAIPPTFYRPYFRIVRFDVSAMEKNASNLVKAEFRVFRLQNPKARVPEQRIELYQILKSKDLTSPTQRYIDSKVVKTRAEGEWLSFDVTDAVHEWLHHKDRNLGFKISLHCPCCTFVPSNNYIIPNKSEELEARFAGIDGTSTYTSGDQKTIKSTRKKNSGKTPHLLLMLLPSYRLESQQTNRRKKRALDAAYCFRNVQDNCCLRPLYIDFKRDLGWKWIHEPKGYNANFCAGACPYLWSSDTQHSRVLSLYNTINPEASASPCCVSQDLEPLTILYYIGKTPKIEQLSNMIVKSCKCS (SEQ ID NO: 10)

[0160] TGFβ3 SLSLSTCTTLDFGHIKKKRVEAIRGQILSKLRLTSPPEPTVMTHVPYQVLALYNSTRELLEEMHGEREEGCTQENTESEYYAKEIHKFDMIQGLAEHNELAVCPKGITSKVFRFNVSSVEKNRTNLFRAEFRVLRVPNPSSKRNEQRIELFQILRPDEHIAKQRYIGGKNLPTRGTAEWLSFDVTDTVREWLLRRESNLGLEISIHCPCHTFQPNGDILENIHEVMEIKFKGVDNEDDHGRGDLGRLKKQKDHHNPHLILMMIPPHRLDNPGQGGQRKKRALDTNYCFRNLEENCCVRPLYIDFRQDLGWKWVHEPKGYYANFCSGPCPYLRSADTTHSTVLGLYNTLNPEASASPCCVPQDLEPLTILYYVGRTPKVEQLSNMVVKSCKCS (SEQ ID NO: 11)

[0161] JPEG2025172758000001.jpg229166JPEG2025172758000002.jpg234166JPEG2025172758000003.jpg235166 JPEG2025172758000004.jpg234166JPEG2025172758000005.jpg235166JPEG2025172758000006.jpg121166

[0162] JPEG2025172758000007.jpg237166JPEG2025172758000008.jpg234166JPEG2025172758000009.jpg235166JPEG2025172758000010.jpg61166

[0163] In some embodiments, the antibodies, or antigen-binding portions thereof, described herein are capable of selectively binding to the LTBP-TGFβ1 complex. In some embodiments, the antigenic protein complex (e.g., the LTBP-TGFβ1 complex) may comprise an LTBP protein selected from the following: LTBP1, LTBP2, LTBP3, and LTBP4.

[0164] In some embodiments, the antibody, or antigen-binding portion thereof, selectively binds to the LTBP1-TGFβ1 complex. In some embodiments, the LTBP1 protein is a naturally occurring protein. In some embodiments, the LTBP1 protein is a non-naturally occurring protein. In some embodiments, the LTBP1 protein is a recombinant protein. Such recombinant LTBP1 proteins may comprise LTBP1, or a splice variant thereof, and / or a fragment thereof. The recombinant LTBP1 protein may be modified to include one or more detectable labels. In some embodiments, the LTBP1 protein comprises a leader sequence (e.g., a native or non-native leader sequence). In some embodiments, the LTBP1 protein does not comprise a leader sequence (i.e., the leader sequence is processed or cleaved). Such detectable labels may include, but are not limited to, a biotin label, a polyhistidine tag, a myc tag, an HA tag, and / or a fluorescent tag. In some embodiments, the LTBP1 protein is a mammalian LTBP1 protein. In some embodiments, the LTBP1 protein is a human, monkey, mouse, or rat LTBP1 protein. In some embodiments, the LTBP1 protein comprises the amino acid sequence set forth in SEQ ID NO: 32 in Table 3. In some embodiments, the LTBP1 protein comprises the amino acid sequence set forth in SEQ ID NO: 33 or SEQ ID NO: 34 in Table 3.

[0165] In some embodiments, the antibodies, or antigen-binding portions thereof, described herein are capable of binding to the LTBP3-TGFβ1 complex. In some embodiments, the LTBP3 protein is a naturally occurring protein. In some embodiments, the LTBP3 protein is a non-naturally occurring protein. In some embodiments, the LTBP3 protein is a recombinant protein. Such recombinant LTBP3 proteins may comprise LTBP3, or splice variants and / or fragments thereof. In some embodiments, the LTBP3 protein comprises a leader sequence (e.g., a native or non-native leader sequence). In some embodiments, the LTBP3 protein does not comprise a leader sequence (i.e., the leader sequence is processed or cleaved). The recombinant LTBP3 protein may be modified to include one or more detectable labels. Such detectable labels may include, but are not limited to, a biotin label, a polyhistidine tag, a myc tag, an HA tag, and / or a fluorescent tag. In some embodiments, the LTBP3 protein is a mammalian LTBP3 protein. In some embodiments, the LTBP3 protein is a human, monkey, mouse, or rat LTBP3 protein. In some embodiments, the LTBP3 protein comprises the amino acid sequence set forth in SEQ ID NO: 35. In some embodiments, the LTBP3 protein comprises the amino acid sequence set forth in SEQ ID NO: 36 or 37.

[0166] JPEG2025172758000011.jpg235166JPEG2025172758000012.jpg237166JPEG2025172758000013.jpg236166JPEG2025172758000014.jpg238166 JPEG2025172758000015.jpg236166JPEG2025172758000016.jpg237166JPEG2025172758000017.jpg238166JPEG2025172758000018.jpg235166 JPEG2025172758000019.jpg236166JPEG2025172758000020.jpg236166JPEG2025172758000021.jpg237166JPEG2025172758000022.jpg129166

[0167] In exemplary embodiments, inhibitors, e.g., antibodies, and antigen-binding portions thereof, that selectively bind to LTBP1-TGFβ1 and / or LTBP3-TGFβ1 do not bind to a complex comprising TGFβ1 and GARP or LRRC33. In one embodiment, the antibody, or antigen-binding portion thereof, does not bind to a GARP protein having the sequence set forth in SEQ ID NO: 38 or SEQ ID NO: 39, and does not bind to a complex comprising said GARP protein. In another embodiment, the inhibitor, e.g., antibody, or antigen-binding portion thereof, does not bind to a GARP protein having the sequence set forth in SEQ ID NO: 40 or SEQ ID NO: 41, and does not bind to a complex comprising said GARP protein. In one embodiment, the inhibitor, e.g., antibody, or antigen-binding portion thereof, does not bind to an LRRC33 protein having the sequence set forth in SEQ ID NO: 42 or SEQ ID NO: 43, and does not bind to a complex comprising said LRRC33 protein. In one embodiment, the inhibitor, e.g., antibody, or antigen-binding portion thereof, does not bind to a GARP / LRRC33 chimera, e.g., a GARP / LRRC33 chimera set forth in SEQ ID NO: 44.

[0168] JPEG2025172758000023.jpg220166JPEG2025172758000024.jpg224166JPEG2025172758000025.jpg22616 6JPEG2025172758000026.jpg224166JPEG2025172758000027.jpg220166JPEG2025172758000028.jpg75166

[0169] In another aspect, the present invention provides a method for inhibiting TGFβ1 activation in the context of LTBP1 and / or LTBP3. In one embodiment, the method comprises exposing an LTBP1-proTGFβ1 complex or an LTBP3-proTGFβ1 complex to an inhibitor, antibody or antigen-binding portion thereof, and / or pharmaceutical composition described herein. For example, in one embodiment, the inhibitor is an inhibitor of extracellular matrix-associated TGFβ1 activation that selectively binds to the proTGFβ1 latent complex presented by LTBP1 / 3. In one embodiment, the inhibitor does not inhibit immune cell-associated TGFβ1 activation, e.g., immune cell-associated TGFβ1 activation resulting from activation of the proTGFβ1 latent complex presented by GARP. In another embodiment, the antibody, or antigen-binding portion thereof, selectively binds to the LTBP1-proTGFβ1 latent complex and / or the LTBP3-proTGFβ1 latent complex, thereby modulating the release of mature TGFβ1 growth factor from the latent complex, wherein the antibody, or antigen-binding portion thereof, does not bind to mature TGFβ1 alone or to the GARP-proTGFβ1 latent complex. In one embodiment, the antibody, or antigen-binding portion thereof, inhibits the release of mature TGFβ1 from the LTBP1-proTGFβ1 complex and / or the LTBP3-proTGFβ1 complex. In one embodiment, the antibody, or antigen-binding portion thereof, does not inhibit the release of mature TGFβ1 from the GARP-proTGFβ1 complex or the LRRC33-proTGFβ1 complex.

[0170] In one embodiment, the method is performed in vitro. In another embodiment, the method is performed in vivo. In one embodiment, the LTBP1-proTGFβ1 complex or the LTBP3-proTGFβ1 complex is present in an extracellular matrix. The extracellular matrix may comprise, for example, fibrillin and / or fibronectin. In some embodiments, the extracellular matrix comprises a protein containing an RGD motif.

[0171] In some embodiments of the foregoing aspects, the antibody, or antigen-binding portion thereof, does not stimulate immune effector cells. In one embodiment, the antibody, or antigen-binding portion thereof, inhibits release of mature TGFβ1 from LTBP1-proTGFβ1 complexes and / or LTBP3-proTGFβ1 complexes, but does not inhibit release of mature TGFβ1 from GARP-proTGFβ1 complexes and / or LRRC33-proTGFβ1 complexes.

[0172] In some embodiments, inhibitors, e.g., antibodies, of the present disclosure that selectively bind to the LTBP1-TGFβ1 complex and / or the LTBP3-TGFβ1 complex have relatively high affinity, e.g., 10 -6 M, 10 -7 M, 10 -8 M, 10 -9 M, 10 -10 M, 10 -11 A dissociation constant (K D In one embodiment, the antibody, or antigen-binding portion thereof, can bind to the LTBP1-TGFβ1 complex and / or the LTBP3-TGFβ1 complex at about 10 -8 M, about 10 -9 M, about 10 -10 M, about 10 -11 M, about 10 -12 M, or about 10 -13 Dissociation constant of M (K D) binds to the LTBP1-TGFβ1 complex and / or the LTBP3-TGFβ1 complex. For example, an antibody that selectively binds to the LTBP1-TGFβ1 complex and / or the LTBP3-TGFβ1 complex can bind to the complex with an affinity of 5 pM to 500 nM, e.g., 10 pM to 100 nM, e.g., 50 pM to 50 nM. In one embodiment, the antibody, or antigen-binding fragment thereof, can bind to the LTBP1-TGFβ1 complex and / or the LTBP3-TGFβ1 complex with an affinity of less than about 300 nM, e.g., about 20 nM or less, about 10 nM or less, about 500 pM or less, or about 5 pM or less. For example, the antibody, or antigen-binding fragment thereof, can bind to the LTBP1-TGFβ1 complex and / or the LTBP3-TGFβ1 complex with an affinity of about 1 nm to about 350 nm, about 10 nm to about 200 nm, about 15 nm to about 250 nm, about 20 nm to about 200 nm, about 1 nm, about 20 nm, about 25 nm, about 50 nm, about 100 nm, about 150 nm, about 200 nm, about 250 nm, about 300 nm, or about 500 pm.

[0173] The present disclosure also includes antibodies or antigen-binding fragments that compete with any of the antibodies described herein for binding to the LTBP1-TGFβ1 complex and / or the LTBP3-TGFβ1 complex. In some embodiments, such antibodies have an affinity for the complex of 50 nM or less (e.g., 20 nM or less, 10 nM or less, 500 pM or less, 50 pM or less, or 5 pM or less). The affinity and binding kinetics of antibodies (or antigen-binding fragments thereof) that selectively bind to the LTBP1-TGFβ1 complex and / or the LTBP3-TGFβ1 complex can be tested using any suitable method, including, but not limited to, biosensor technology (e.g., OCTET or BIACORE).

[0174] In one embodiment, an antibody of the present disclosure, or an antigen-binding fragment thereof, does not compete with antibody SR-Ab1 for binding to the human LTBP1-proTGFβ1 complex.

[0175] An embodiment of the present disclosure relates to an antibody that competes or cross-competes with any antibody provided herein. The term "compete" used herein in reference to an antibody refers to a first antibody that binds to an epitope (e.g., an epitope of the LTBP1-TGFβ1 complex and / or an epitope of the LTBP3-TGFβ1 complex) in a manner sufficiently similar to the binding of a second antibody, such that the binding of the first antibody to that epitope is detectably reduced in the presence of the second antibody compared to the binding of the first antibody in the absence of the second antibody. Alternatively, the binding of the second antibody to that epitope may also be detectably reduced in the presence of the first antibody, but this is not necessarily the case. That is, the first antibody can inhibit the binding of the second antibody to that epitope without the second antibody inhibiting the binding of the first antibody to its respective epitope. However, if each antibody detectably inhibits the binding of the other antibody to its epitope or ligand, whether to an equal, greater, or lesser extent, the antibodies are said to "cross-compete" with each other for binding to their respective epitope(s). Both competing and cross-competing antibodies are within the scope of the present disclosure. Regardless of the mechanism by which such competition or cross-competition occurs (e.g., steric hindrance, conformational change, or binding to a common epitope or portion thereof), one skilled in the art will understand that such competing and / or cross-competing antibodies are encompassed and may be useful in the methods and / or compositions provided herein.

[0176] Aspects of the present disclosure relate to antibodies that compete or cross-compete with any of the specific antibodies, or antigen-binding portions thereof, provided herein, for example, antibodies having one or more CDR sequences (1, 2, 3, 4, 5, or 6 CDR sequences) set forth in Table 5. In one embodiment, the present invention provides antibodies, and antigen-binding fragments thereof, that compete or cross-compete with an antibody having heavy chain CDR sequences comprising SEQ ID NO:1, SEQ ID NO:2, and SEQ ID NO:3 set forth in Table 5, and / or light chain CDR sequences comprising SEQ ID NO:4, SEQ ID NO:5, and SEQ ID NO:6 set forth in Table 5. In one embodiment, the present invention provides antibodies that compete or cross-compete with an antibody, or antigen-binding portion thereof, having a heavy chain variable region sequence comprising SEQ ID NO:7 and / or a light chain variable region sequence comprising SEQ ID NO:8. In some embodiments, an antibody, or antigen-binding portion thereof, binds at or near the same epitope as any of the antibodies provided herein. In some embodiments, an antibody, or antigen-binding portion thereof, binds near an epitope if it binds within 15 or fewer amino acid residues of the epitope. In some embodiments, any of the antibodies, or antigen-binding portions thereof, provided herein binds within 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 amino acid residues of the epitope bound by any of the antibodies provided herein.

[0177] In another embodiment, the equilibrium dissociation constant (K D ) is 10 -6 Provided herein are antibodies, or antigen-binding portions thereof, that compete or cross-compete for binding to any of the antigens provided herein (e.g., LTBP1-TGFβ1 complex and / or LTBP3-TGFβ1 complex) with a binding affinity of less than 10 M. In other embodiments, the antibodies -11 M~10 -6 K within M D In other embodiments, the antibody has a K of <50 nM as measured by a suitable in vitro binding assay, e.g., BLI, such as Octet®.D In another embodiment, the antibody has a K of <10 nM as measured by a suitable in vitro binding assay, e.g., BLI, such as Octet. D and compete or cross-compete for binding to the human LTBP1-TGFβ1 complex and / or the human LTBP3-TGFβ1 complex.

[0178] In some embodiments, the antibody or antigen-binding portion competes or cross-competes with an antibody having the heavy chain variable region sequence and light chain variable region sequence of Ab42 shown in Table 6 (e.g., SEQ ID NOs: 318 and 319, respectively). The antibody has a K of <10 nM as determined by a suitable in vitro binding assay, e.g., BLI such as Octet. D The antibody may be capable of competing or cross-competing for binding to the human LTBP1-TGFβ1 complex and / or the human LTBP3-TGFβ1 complex with a K of <5 nM as determined by a suitable in vitro binding assay, e.g., BLI, such as Octet. D The antibody may be capable of competing or cross-competing for binding to the human LTBP1-TGFβ1 complex and / or the human LTBP3-TGFβ1 complex with a K of <5 nM as determined by a suitable in vitro binding assay, e.g., BLI, such as Octet. D The antibody may bind to the human LTBP1-TGFβ1 complex and the human LTBP3-TGFβ1 complex at a K of 0.05. The antibody may not exhibit any detectable binding to the human GARP-proTGFβ1 complex in a suitable in vitro binding assay, such as BLI (e.g., Octet). The antibody may not exhibit detectable binding to the human GARP-proTGFβ1 complex when measured by BLI under the same assay conditions as those used to measure binding to the human LTBP1-proTGFβ1 complex and / or the human LTBP3-TGFβ1 complex. Alternatively, or in addition, the antibody or antigen-binding portion may exhibit a K of 0.05 when binding to the human GARP-proTGFβ1 complex under the same assay conditions. D At least 50 times lower than D(K when binding to the human LRRC33-proTGFβ1 complex) D The antibody may be capable of binding to (eg, selectively binding to) the human LTBP1-proTGFβ1 complex and / or the human LTBP3-TGFβ1 complex, with a binding affinity of at least 50-fold lower than that of the antibody.

[0179] In some embodiments, the antibody competes or cross-competes with an antibody having the heavy chain variable region sequence and light chain variable region sequence of Ab63 shown in Table 6 (e.g., SEQ ID NOs: 360 and 361, respectively). The antibody has a K of <10 nM as determined by a suitable in vitro binding assay, e.g., BLI, such as Octet. D The antibody may be capable of competing or cross-competing for binding to the human LTBP1-TGFβ1 complex and / or the human LTBP3-TGFβ1 complex with a K of <5 nM as determined by a suitable in vitro binding assay, e.g., BLI, such as Octet. D The antibody may be capable of competing or cross-competing for binding to the human LTBP1-TGFβ1 complex and / or the human LTBP3-TGFβ1 complex with a K of <5 nM as determined by a suitable in vitro binding assay, e.g., BLI, such as Octet. D The antibody may bind to the human LTBP1-TGFβ1 complex and the human LTBP3-TGFβ1 complex at a K of 0.05. The antibody may not exhibit any detectable binding to the human GARP-proTGFβ1 complex in a suitable in vitro binding assay, such as BLI (e.g., Octet). The antibody may not exhibit detectable binding to the human GARP-proTGFβ1 complex when measured by BLI under the same assay conditions as those used to measure binding to the human LTBP1-proTGFβ1 complex and / or the human LTBP3-TGFβ1 complex. Alternatively, or in addition, the antibody or antigen-binding portion may exhibit a K of 0.05 when binding to the human GARP-proTGFβ1 complex under the same assay conditions. D At least 50 times lower than D (K when binding to the human LRRC33-proTGFβ1 complex) DThe antibody may be capable of binding to (eg, selectively binding to) the human LTBP1-proTGFβ1 complex and / or the human LTBP3-TGFβ1 complex, with a binding affinity of at least 50-fold lower than that of the antibody.

[0180] In a further embodiment, an antibody that selectively binds to the human LTBP1-TGFβ1 complex and / or the human LTBP3-TGFβ1 complex may not exhibit significant binding (e.g., may not exhibit a response of more than 0.1 units (nM)) upon exposure to the human GARP-proTGFβ1 complex in a BLI assay (e.g., Octet) when the human GARP-proTGFβ1 complex is at a concentration of 200 nM.

[0181] In some embodiments, provided herein are anti-TGFβ1 antibodies, or antigen-binding portions thereof, that compete for binding with the antibodies, or antigen-binding portions thereof, described herein. In some embodiments, provided herein are anti-TGFβ1 antibodies, or antigen-binding portions thereof, that bind to the same epitope as the antibodies, or antigen-binding portions thereof, described herein.

[0182] The antibodies provided herein can be characterized using any suitable method. For example, one method is to identify the epitope to which the antigen binds, i.e., "epitope mapping." Many suitable methods exist for mapping and characterizing the location of epitopes on proteins, including analysis of the crystal structure of the antibody-antigen complex, competitive assays, gene fragment expression assays, and synthetic peptide-based assays, as described, for example, in Chapter 11 of Harlow and Lane, "Using Antibodies," a Laboratory Manual, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY, 1999. In a further example, epitope mapping can be used to determine the sequence to which an antibody binds. The epitope may be a linear epitope, i.e., contained within a single stretch of amino acids, or a conformational epitope formed by three-dimensional interactions of amino acids that are not necessarily contained within a single stretch (primary structure linear sequence). In some embodiments, the epitope is a TGFβ1 epitope that is available for binding by an antibody, or antigen-binding portion thereof, described herein only when TGFβ1 is in an LTBP1-TGFβ1 complex and / or an LTBP3-TGFβ1 complex. In some embodiments, the epitope is present on the LTBP1 / 3-TGFβ1 complex and not on the GARP-TGFβ1 complex and / or the LRRC33-TGFβ1 complex. In some embodiments, the epitope is available due to a conformational change in LTBP1 / 3 and / or TGFβ1 that occurs when LTBP1 / 3 and TGFβ1 form a complex. In this embodiment, the epitope is not present in LTBP1 / 3 or TGFβ1 when the proteins are not associated in a complex. In one embodiment, the epitope is present on TGFβ1 when TGFβ1 is in a complex with LTBP1 or LTBP3. In another embodiment, the epitope is present on LTBP1 when LTBP1 is in a complex with TGFβ1.In another embodiment, the epitope is present on LTBP3 when LTBP3 is in a complex with TGFβ1. In another embodiment, the epitope includes residues from both LTBP1 and TGFβ1. In another embodiment, the epitope includes residues from both LTBP3 and TGFβ1. Peptides of different lengths (e.g., at least 4-6 amino acids) can be isolated or synthesized (e.g., recombinantly) and used for antibody binding assays. In another example, the epitope to which an antibody binds can be determined in a systematic screen by using overlapping peptides derived from the target antigen sequence and determining binding by the antibody. In a gene fragment expression assay, the open reading frame encoding the target antigen is fragmented either randomly or by specific genetic constructs, and the reactivity of the expressed fragments of the antigen with the antibody being tested is determined. Gene fragments can be produced, for example, by PCR, then transcribed and translated into protein in vitro in the presence of radioactive amino acids. Antibody binding to the radiolabeled antigen fragments is then determined by immunoprecipitation and gel electrophoresis. Specific epitopes can also be identified by using large libraries of random peptide sequences (phage libraries) displayed on the surface of phage particles. Alternatively, a predetermined library of overlapping peptide fragments can be tested for binding to a test antibody in a simple binding assay. In a further example, mutagenesis of the antigen-binding domain, domain-swapping experiments, and alanine-scanning mutagenesis can be performed to identify residues necessary, sufficient, and / or essential for epitope binding. For example, domain-swapping experiments can be performed using mutant versions of the target antigen, in which various fragments of the LTBP1-TGFβ1 complex or the LTBP3-TGFβ1 complex are replaced (swapped) with sequences from a closely related but antigenically distinct protein, such as another member of the TGFβ protein family (e.g., GDF11).By assessing antibody binding to mutant forms of the LTBP1-TGFβ1 complex and / or the LTBP3-TGFβ1 complex, the importance of particular antigen fragments to antibody binding can be assessed.

[0183] Alternatively, a competition assay can be performed with another antibody known to bind to the same antigen to determine whether the antibody is able to bind to the same epitope as another antibody. Competition assays are well known to those skilled in the art.

[0184] Furthermore, the interaction of any antibody provided herein with one or more residues in the LTBP1-TGFβ1 complex and / or the LTBP3-TGFβ1 complex can be determined by routine techniques. For example, a crystal structure can be determined, thereby determining the distance between the residues in the LTBP1-TGFβ1 complex and / or the LTBP3-TGFβ1 complex and one or more residues in the antibody. Based on such distance, it can be determined whether a specific residue in the LTBP1 / 3-TGFβ1 complex interacts with one or more residues in the antibody. Furthermore, the preferential binding of a candidate antibody can be determined using appropriate methods, such as competition assays and targeted mutagenesis assays.

[0185] In some embodiments, antibodies of the invention, or antigen-binding portions thereof, that selectively bind to the LTBP1-TGFβ1 complex and / or the LTBP3-TGFβ1 complex comprise one or more of the complementarity-determining regions (CDRs) set forth in Table 5. In some embodiments, the invention provides nucleic acid molecules encoding antibodies, or antigen-binding portions thereof, that selectively bind to the LTBP1-TGFβ1 complex and / or the LTBP3-TGFβ1 complex described herein. In one embodiment, the nucleic acid molecule encodes one or more of the CDR sequences set forth in Table 5.

[0186] JPEG2025172758000029.jpg27166JPEG2025172758000030.jpg254134JPEG2025172758000031.jp g254123JPEG2025172758000032.jpg254117JPEG2025172758000033.jpg254117JPEG20251727580 00034.jpg254118JPEG2025172758000035.jpg254117JPEG2025172758000036.jpg254118JPEG202 5172758000037.jpg254117JPEG2025172758000038.jpg254118JPEG2025172758000039.jpg254118 JPEG2025172758000040.jpg254116JPEG2025172758000041.jpg254118JPEG2025172758000042.j pg254119JPEG2025172758000043.jpg254117JPEG2025172758000044.jpg254117JPEG20251727580 00045.jpg254116JPEG2025172758000046.jpg254117JPEG2025172758000047.jpg254118JPEG202 5172758000048.jpg254118JPEG2025172758000049.jpg254118JPEG2025172758000050.jpg212166

[0187] In some embodiments, antibodies of the invention that selectively bind to the LTBP1-TGFβ complex and / or the LTBP3-TGFβ complex comprise any antibody, or antigen-binding portion thereof, comprising CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, or CDRL3, or a combination thereof, provided in Table 5. In some embodiments, antibodies that selectively bind to the LTBP1-TGFβ complex and / or the LTBP3-TGFβ complex comprise CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 provided in Table 5.

[0188] The present invention also provides nucleic acid sequences that encode molecules comprising a CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, or CDRL3, or a combination thereof, provided in Table 5.

[0189] Antibody heavy and light chain CDR3 domains may play a particularly important role in the binding specificity / affinity of an antibody for an antigen. Thus, in some embodiments, antibodies, or antigen-binding portions thereof, that selectively bind to the LTBP1-TGFβ complex and / or the LTBP3-TGFβ complex, or nucleic acid molecules encoding these antibodies or antigen-binding portions thereof, may comprise at least the heavy and / or light chain CDR3 of an antibody shown in Table 5.

[0190] An embodiment of the present invention relates to a monoclonal antibody, or antigen-binding portion thereof, that selectively binds to the LTBP1-TGFβ complex and / or the LTBP3-TGFβ complex and comprises six complementarity-determining regions (CDRs): CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3. The antibody, or antigen-binding portion thereof, may have the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of one of the antibodies shown in Table 5 (e.g., Ab42).

[0191] In some embodiments, CDRH1 comprises the sequence set forth in SEQ ID NO: 1. In some embodiments, CDRH2 comprises the sequence set forth in SEQ ID NO: 2. In some embodiments, CDRH3 comprises the sequence set forth in SEQ ID NO: 3. In some embodiments, CDRL1 comprises the sequence set forth in SEQ ID NO: 4. In some embodiments, CDRL2 comprises the sequence set forth in SEQ ID NO: 5. In some embodiments, CDRL3 comprises the sequence set forth in SEQ ID NO: 6.

[0192] In one aspect, the present invention provides an isolated antibody, or antigen-binding fragment thereof, that specifically binds to the human LTBP1-proTGFβ complex and / or the human LTBP3-proTGFβ complex but does not bind to the human GARP-proTGFβ1 complex; wherein the antibody or antigen-binding fragment thereof does not bind to mature TGFβ1, mature TGFβ2, or mature TGFβ3; and wherein the antibody or antigen-binding fragment thereof is a fully human or humanized antibody or antigen-binding fragment thereof, and wherein the antibody or antigen-binding fragment thereof comprises at least three CDRs selected from the following: CDR-H1: SEQ ID NO: 1; CDR-H2: SEQ ID NO: 2; CDR-H3: SEQ ID NO: 3; CDR-L1: SEQ ID NO: 4; CDR-L2: SEQ ID NO: 5; and CDR-L3: SEQ ID NO: 6, and may comprise up to one or more amino acid changes for each CDR. In some embodiments, the one or more amino acid changes comprise up to 1, 2, 3, 4, 5, or 6 amino acid changes for each CDR.

[0193] In some embodiments (e.g., with respect to antibody SR-AB2 shown in Table 5), the antibody, or antigen-binding portion thereof, that selectively binds to the LTBP1-TGFβ complex and / or the LTBP3-TGFβ complex comprises a CDRH1 comprising the amino acid sequence set forth in SEQ ID NO: 1, a CDRH2 comprising the amino acid sequence set forth in SEQ ID NO: 2, a CDRH3 comprising the amino acid sequence set forth in SEQ ID NO: 3, a CDRL1 comprising the amino acid sequence set forth in SEQ ID NO: 4, a CDRL2 comprising the amino acid sequence set forth in SEQ ID NO: 5, and a CDRL3 comprising the amino acid sequence set forth in SEQ ID NO: 6.

[0194] In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising a complementarity determining region 3 (CDR3) having the amino acid sequence of SEQ ID NO: 3, and a light chain variable region comprising a CDR3 having the amino acid sequence of SEQ ID NO: 6. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising a complementarity determining region 2 (CDR2) having the amino acid sequence of SEQ ID NO: 2, and a light chain variable region comprising a CDR2 having the amino acid sequence of SEQ ID NO: 5. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising a complementarity determining region 1 (CDR1) having the amino acid sequence of SEQ ID NO: 1, and a light chain variable region comprising a CDR1 having the amino acid sequence of SEQ ID NO: 4.

[0195] The amino acid sequences of the heavy chain variable region (HCVR) and light chain variable region (LCVR) of the antibodies shown in Table 5 (eg, SR-AB2) are provided in Table 6.

[0196] In some embodiments, CDRH1 comprises the sequence set forth in SEQ ID NO: 94. In some embodiments, CDRH2 comprises the sequence set forth in SEQ ID NO: 95. In some embodiments, CDRH3 comprises the sequence set forth in SEQ ID NO: 96. In some embodiments, CDRL1 comprises the sequence set forth in SEQ ID NO: 97. In some embodiments, CDRL2 comprises the sequence set forth in SEQ ID NO: 98. In some embodiments, CDRL3 comprises the sequence set forth in SEQ ID NO: 99.

[0197] In one aspect, the present invention provides an isolated antibody, or antigen-binding fragment thereof, that specifically binds to the human LTBP1-proTGFβ complex and / or the human LTBP3-proTGFβ complex but does not bind to the human GARP-proTGFβ1 complex; wherein the antibody or antigen-binding fragment thereof does not bind to mature TGFβ1, mature TGFβ2, or mature TGFβ3; and wherein the antibody or antigen-binding fragment thereof is a fully human or humanized antibody or antigen-binding fragment thereof, and wherein the antibody or antigen-binding fragment thereof comprises at least three CDRs selected from the following: CDR-H1: SEQ ID NO: 94; CDR-H2: SEQ ID NO: 95; CDR-H3: SEQ ID NO: 96; CDR-L1: SEQ ID NO: 97; CDR-L2: SEQ ID NO: 98; and CDR-L3: SEQ ID NO: 99, and optionally comprises one or more amino acid changes for each CDR. In some embodiments, the one or more amino acid changes comprise 1, 2, 3, 4, 5, or up to 6 amino acid changes for each CDR.

[0198] In some embodiments (e.g., with respect to antibody SR-AB10 shown in Table 5), the antibody, or antigen-binding portion thereof, that selectively binds to the LTBP1-TGFβ complex and / or the LTBP3-TGFβ complex comprises a CDRH1 comprising the amino acid sequence set forth in SEQ ID NO: 94, a CDRH2 comprising the amino acid sequence set forth in SEQ ID NO: 95, a CDRH3 comprising the amino acid sequence set forth in SEQ ID NO: 96, a CDRL1 comprising the amino acid sequence set forth in SEQ ID NO: 97, a CDRL2 comprising the amino acid sequence set forth in SEQ ID NO: 98, and a CDRL3 comprising the amino acid sequence set forth in SEQ ID NO: 99.

[0199] In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising a complementarity determining region 3 (CDR3) having the amino acid sequence of SEQ ID NO: 96, and a light chain variable region comprising a CDR3 having the amino acid sequence of SEQ ID NO: 99. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising a complementarity determining region 2 (CDR2) having the amino acid sequence of SEQ ID NO: 95, and a light chain variable region comprising a CDR2 having the amino acid sequence of SEQ ID NO: 98. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising a complementarity determining region 1 (CDR1) having the amino acid sequence of SEQ ID NO: 94, and a light chain variable region comprising a CDR1 having the amino acid sequence of SEQ ID NO: 97.

[0200] The amino acid sequences of the heavy chain variable region (HCVR) and light chain variable region (LCVR) of the antibodies shown in Table 5 (eg, SR-AB10) are provided in Table 6.

[0201] In some embodiments, CDRH1 comprises the sequence set forth in SEQ ID NO: 100. In some embodiments, CDRH2 comprises the sequence set forth in SEQ ID NO: 101. In some embodiments, CDRH3 comprises the sequence set forth in SEQ ID NO: 102. In some embodiments, CDRL1 comprises the sequence set forth in SEQ ID NO: 103. In some embodiments, CDRL2 comprises the sequence set forth in SEQ ID NO: 104. In some embodiments, CDRL3 comprises the sequence set forth in SEQ ID NO: 105.

[0202] In one aspect, the present invention provides an isolated antibody, or antigen-binding fragment thereof, that specifically binds to the human LTBP1-proTGFβ complex and / or the human LTBP3-proTGFβ complex but not to the human GARP-proTGFβ1 complex; wherein the antibody or antigen-binding fragment thereof does not bind to mature TGFβ1, mature TGFβ2, or mature TGFβ3; and wherein the antibody or antigen-binding fragment thereof is a fully human or humanized antibody or antigen-binding fragment thereof, and wherein the antibody or antigen-binding fragment thereof comprises at least three CDRs selected from the following: CDR-H1: SEQ ID NO: 100; CDR-H2: SEQ ID NO: 101; CDR-H3: SEQ ID NO: 102; CDR-L1: SEQ ID NO: 103; CDR-L2: SEQ ID NO: 104; and CDR-L3: SEQ ID NO: 105, and optionally comprises one or more amino acid changes for each CDR. In some embodiments, the one or more amino acid changes comprise 1, 2, 3, 4, 5, or up to 6 amino acid changes for each CDR.

[0203] In some embodiments (e.g., with respect to antibody SR-AB13 shown in Table 5), the antibody, or antigen-binding portion thereof, that selectively binds to the LTBP1-TGFβ complex and / or the LTBP3-TGFβ complex comprises a CDRH1 comprising the amino acid sequence set forth in SEQ ID NO: 100, a CDRH2 comprising the amino acid sequence set forth in SEQ ID NO: 101, a CDRH3 comprising the amino acid sequence set forth in SEQ ID NO: 102, a CDRL1 comprising the amino acid sequence set forth in SEQ ID NO: 103, a CDRL2 comprising the amino acid sequence set forth in SEQ ID NO: 104, and a CDRL3 comprising the amino acid sequence set forth in SEQ ID NO: 105.

[0204] In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising a complementarity determining region 3 (CDR3) having the amino acid sequence of SEQ ID NO: 102, and a light chain variable region comprising a CDR3 having the amino acid sequence of SEQ ID NO: 105. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising a complementarity determining region 2 (CDR2) having the amino acid sequence of SEQ ID NO: 101, and a light chain variable region comprising a CDR2 having the amino acid sequence of SEQ ID NO: 104. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising a complementarity determining region 1 (CDR1) having the amino acid sequence of SEQ ID NO: 100, and a light chain variable region comprising a CDR1 having the amino acid sequence of SEQ ID NO: 103.

[0205] The amino acid sequences of the heavy chain variable region (HCVR) and light chain variable region (LCVR) of the antibodies shown in Table 5 (eg, SR-AB13) are provided in Table 6.

[0206] In some embodiments, CDRH1 comprises the sequence set forth in SEQ ID NO: 124. In some embodiments, CDRH2 comprises the sequence set forth in SEQ ID NO: 125. In some embodiments, CDRH3 comprises the sequence set forth in SEQ ID NO: 126. In some embodiments, CDRL1 comprises the sequence set forth in SEQ ID NO: 127. In some embodiments, CDRL2 comprises the sequence set forth in SEQ ID NO: 128. In some embodiments, CDRL3 comprises the sequence set forth in SEQ ID NO: 129.

[0207] In one aspect, the present invention provides an isolated antibody, or antigen-binding fragment thereof, that specifically binds to human LTBP1-proTGFβ complex and / or human LTBP3-proTGFβ complex; wherein the antibody or antigen-binding fragment thereof does not bind to mature TGFβ1, mature TGFβ2, or mature TGFβ3; and wherein the antibody or antigen-binding fragment thereof is a fully human or humanized antibody or antigen-binding fragment thereof, and wherein the antibody or antigen-binding fragment thereof comprises at least three CDRs (which may be all six) selected from the following: CDR-H1: SEQ ID NO: 124; CDR-H2: SEQ ID NO: 125; CDR-H3: SEQ ID NO: 126; CDR-L1: SEQ ID NO: 127; CDR-L2: SEQ ID NO: 128; and CDR-L3: SEQ ID NO: 129, and may comprise up to one or more amino acid changes for each CDR. In some embodiments, the one or more amino acid changes comprise 1, 2, 3, 4, 5, or up to 6 amino acid changes for each CDR.

[0208] In some embodiments (e.g., with respect to antibody SR-AB31 shown in Table 5), the antibody, or antigen-binding portion thereof, that selectively binds to the LTBP1-TGFβ complex and / or the LTBP3-TGFβ complex comprises a CDRH1 comprising the amino acid sequence set forth in SEQ ID NO: 124, a CDRH2 comprising the amino acid sequence set forth in SEQ ID NO: 125, a CDRH3 comprising the amino acid sequence set forth in SEQ ID NO: 126, a CDRL1 comprising the amino acid sequence set forth in SEQ ID NO: 127, a CDRL2 comprising the amino acid sequence set forth in SEQ ID NO: 128, and a CDRL3 comprising the amino acid sequence set forth in SEQ ID NO: 129.

[0209] In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising a complementarity determining region 3 (CDR3) having the amino acid sequence of SEQ ID NO: 126, and a light chain variable region comprising a CDR3 having the amino acid sequence of SEQ ID NO: 129. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising a complementarity determining region 2 (CDR2) having the amino acid sequence of SEQ ID NO: 125, and a light chain variable region comprising a CDR2 having the amino acid sequence of SEQ ID NO: 128. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising a complementarity determining region 1 (CDR1) having the amino acid sequence of SEQ ID NO: 124, and a light chain variable region comprising a CDR1 having the amino acid sequence of SEQ ID NO: 127.

[0210] The amino acid sequences of the HCVRs and LCVRs of the antibodies shown in Table 5 (eg, SR-AB31) are provided in Table 6.

[0211] In some embodiments, CDRH1 comprises the sequence set forth in SEQ ID NO: 166. In some embodiments, CDRH2 comprises the sequence set forth in SEQ ID NO: 167. In some embodiments, CDRH3 comprises the sequence set forth in SEQ ID NO: 168. In some embodiments, CDRL1 comprises the sequence set forth in SEQ ID NO: 169. In some embodiments, CDRL2 comprises the sequence set forth in SEQ ID NO: 170. In some embodiments, CDRL3 comprises the sequence set forth in SEQ ID NO: 171.

[0212] In one aspect, the present invention provides an isolated antibody, or antigen-binding fragment thereof, that specifically binds to human LTBP1-proTGFβ complex and / or human LTBP3-proTGFβ complex; wherein the antibody or antigen-binding fragment thereof does not bind to mature TGFβ1, mature TGFβ2, or mature TGFβ3; and wherein the antibody or antigen-binding fragment thereof is a fully human or humanized antibody or antigen-binding fragment thereof, and wherein the antibody or antigen-binding fragment thereof comprises at least three CDRs (which may be all six) selected from the following: CDR-H1: SEQ ID NO: 166; CDR-H2: SEQ ID NO: 167; CDR-H3: SEQ ID NO: 168; CDR-L1: SEQ ID NO: 169; CDR-L2: SEQ ID NO: 170; and CDR-L3: SEQ ID NO: 171, and may comprise up to one or more amino acid changes for each CDR. In some embodiments, the one or more amino acid changes comprise 1, 2, 3, 4, 5, or up to 6 amino acid changes for each CDR.

[0213] In some embodiments (e.g., with respect to antibody SR-AB42 shown in Table 5), the antibody, or antigen-binding portion thereof, that selectively binds to the LTBP1-TGFβ complex and / or the LTBP3-TGFβ complex comprises a CDRH1 comprising the amino acid sequence set forth in SEQ ID NO: 166, a CDRH2 comprising the amino acid sequence set forth in SEQ ID NO: 167, a CDRH3 comprising the amino acid sequence set forth in SEQ ID NO: 168, a CDRL1 comprising the amino acid sequence set forth in SEQ ID NO: 169, a CDRL2 comprising the amino acid sequence set forth in SEQ ID NO: 170, and a CDRL3 comprising the amino acid sequence set forth in SEQ ID NO: 171.

[0214] In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising a complementarity determining region 3 (CDR3) having the amino acid sequence of SEQ ID NO: 168, and a light chain variable region comprising a CDR3 having the amino acid sequence of SEQ ID NO: 171. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising a complementarity determining region 2 (CDR2) having the amino acid sequence of SEQ ID NO: 167, and a light chain variable region comprising a CDR2 having the amino acid sequence of SEQ ID NO: 170. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising a complementarity determining region 1 (CDR1) having the amino acid sequence of SEQ ID NO: 166, and a light chain variable region comprising a CDR1 having the amino acid sequence of SEQ ID NO: 169.

[0215] The amino acid sequences of the HCVRs and LCVRs of the antibodies shown in Table 5 (e.g., SR-AB42) are provided in Table 6.

[0216] In some embodiments, CDRH1 comprises the sequence set forth in SEQ ID NO: 292. In some embodiments, CDRH2 comprises the sequence set forth in SEQ ID NO: 293. In some embodiments, CDRH3 comprises the sequence set forth in SEQ ID NO: 294. In some embodiments, CDRL1 comprises the sequence set forth in SEQ ID NO: 295. In some embodiments, CDRL2 comprises the sequence set forth in SEQ ID NO: 296. In some embodiments, CDRL3 comprises the sequence set forth in SEQ ID NO: 297.

[0217] In one aspect, the present invention provides an isolated antibody, or antigen-binding fragment thereof, that specifically binds to human LTBP1-proTGFβ complex and / or human LTBP3-proTGFβ complex; wherein the antibody or antigen-binding fragment thereof does not bind to mature TGFβ1, mature TGFβ2, or mature TGFβ3; and wherein the antibody or antigen-binding fragment thereof is a fully human or humanized antibody or antigen-binding fragment thereof, and wherein the antibody or antigen-binding fragment thereof comprises at least three CDRs (which may be all six) selected from the following: CDR-H1: SEQ ID NO: 292; CDR-H2: SEQ ID NO: 293; CDR-H3: SEQ ID NO: 294; CDR-L1: SEQ ID NO: 295; CDR-L2: SEQ ID NO: 296; and CDR-L3: SEQ ID NO: 297, and may comprise up to one or more amino acid changes for each CDR. In some embodiments, the one or more amino acid changes comprise 1, 2, 3, 4, 5, or up to 6 amino acid changes for each CDR.

[0218] In some embodiments (e.g., with respect to antibody SR-AB63 shown in Table 5), the antibody, or antigen-binding portion thereof, that selectively binds to the LTBP1-TGFβ complex and / or the LTBP3-TGFβ complex comprises a CDRH1 comprising the amino acid sequence set forth in SEQ ID NO:292, a CDRH2 comprising the amino acid sequence set forth in SEQ ID NO:293, a CDRH3 comprising the amino acid sequence set forth in SEQ ID NO:294, a CDRL1 comprising the amino acid sequence set forth in SEQ ID NO:295, a CDRL2 comprising the amino acid sequence set forth in SEQ ID NO:296, and a CDRL3 comprising the amino acid sequence set forth in SEQ ID NO:297.

[0219] In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising a complementarity determining region 3 (CDR3) having the amino acid sequence of SEQ ID NO: 294, and a light chain variable region comprising a CDR3 having the amino acid sequence of SEQ ID NO: 297. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising a complementarity determining region 2 (CDR2) having the amino acid sequence of SEQ ID NO: 293, and a light chain variable region comprising a CDR2 having the amino acid sequence of SEQ ID NO: 296. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising a complementarity determining region 1 (CDR1) having the amino acid sequence of SEQ ID NO: 292, and a light chain variable region comprising a CDR1 having the amino acid sequence of SEQ ID NO: 295.

[0220] The HCVR and LCVR amino acid sequences of the antibodies shown in Table 5 (eg, SR-AB63) are provided in Table 6.

[0221] Ten additional antibodies (Ab3-Ab12) were developed that specifically bind to the LTBP1-TGFβ complex and / or the LTBP3-TGFβ complex and inhibit the release of mature TGFβ presented in the context of LTBP1 / 3. Table 6 provides the HCVR and LCVR amino acid sequences of these additional LTBP context-specific antibodies in addition to the HCVR and LCVR amino acid sequences of the antibodies referenced in Table 5.

[0222] JPEG2025172758000051.jpg241166JPEG2025172758000052.jpg242166JPEG2025172758000053.jpg242166JPEG2025172758000054.jpg24116 6JPEG2025172758000055.jpg241166JPEG2025172758000056.jpg241166JPEG2025172758000057.jpg241166JPEG2025172758000058.jpg56166

[0223] An embodiment of the present invention relates to a monoclonal antibody, or an antigen-binding portion thereof, that selectively binds to an LTBP1-TGFβ complex and / or an LTBP3-TGFβ complex and comprises a heavy chain variable region sequence and a light chain variable region sequence.

[0224] In one aspect, the present invention provides an isolated antibody or antigen-binding fragment thereof that specifically binds to the human LTBP1-proTGFβ complex and / or the human LTBP3-proTGFβ complex but does not bind to the human GARP-proTGFβ1 complex; wherein the antibody or antigen-binding fragment thereof does not bind to mature TGFβ1, mature TGFβ2, or mature TGFβ3; wherein the antibody or antigen-binding fragment thereof is a fully human or humanized antibody or antigen-binding fragment thereof; and wherein the antibody or antigen-binding fragment thereof comprises a variable heavy chain having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to any one of the variable region amino acid sequences shown in Table 6.

[0225] In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:7, SEQ ID NO:74, SEQ ID NO:76, SEQ ID NO:78, SEQ ID NO:80, SEQ ID NO:82, SEQ ID NO:84, SEQ ID NO:86, SEQ ID NO:88, SEQ ID NO:90, SEQ ID NO:92, or SEQ ID NO: 106. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:8, SEQ ID NO:75, SEQ ID NO:77, SEQ ID NO:79, SEQ ID NO:81, SEQ ID NO:83, SEQ ID NO:85, SEQ ID NO:87, SEQ ID NO:89, SEQ ID NO:91, SEQ ID NO:93, or SEQ ID NO:107.

[0226] In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 7, and / or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 8. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 7, or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 8. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:7, and a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:8.

[0227] In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 74, and / or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 75. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 74, or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 75. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:74, and a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:75.

[0228] In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 76, and / or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 77. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 76, or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 77. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:76, and a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:77.

[0229] In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 78, and / or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 79. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 78, or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 79. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:78, and a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:79.

[0230] In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 80, and / or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 81. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 80, or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 81. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:80, and a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:81.

[0231] In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 82, and / or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 83. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 82, or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 83. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 82, and a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 83.

[0232] In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 84, and / or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 85. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 84, or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 85. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:84, and a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:85.

[0233] In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 86, and / or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 87. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 86, or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 87. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:86, and a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:87.

[0234] In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 88, and / or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 89. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 88, or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 89. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:88, and a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:89.

[0235] In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 90, and / or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 91. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 90, or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 91. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:90, and a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:91.

[0236] In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 92, and / or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 93. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 92, or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 93. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:92, and a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:93.

[0237] In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 106, and / or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 107. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 106, or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 107. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 106, and a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 107.

[0238] In one aspect, the present invention provides an isolated antibody or antigen-binding fragment thereof that specifically binds to the human LTBP1-proTGFβ complex and / or the human LTBP3-proTGFβ complex. The antibody may selectively bind to the human LTBP1-proTGFβ complex and / or the human LTBP3-proTGFβ complex. The antibody or antigen-binding fragment thereof may not bind to mature TGFβ1, mature TGFβ2, or mature TGFβ3. The antibody or antigen-binding fragment thereof may be fully human or humanized. The antibody or antigen-binding fragment thereof may comprise a variable heavy chain having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to any one of the variable region amino acid sequences shown in Table 6. In some embodiments, the level of identity is at least 95% (and may be at least 98%).

[0239] Thus, in one embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:318, and / or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:319. The antibody, or antigen-binding fragment thereof, may comprise a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 318, or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 319. The antibody, or antigen-binding fragment thereof, may comprise a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 318, and a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 319.

[0240] In another embodiment, the antibody, or antigen-binding fragment thereof, comprises a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 360, and / or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 361. The antibody, or antigen-binding fragment thereof, may comprise a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 360, or a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 361. The antibody, or antigen-binding fragment thereof, may comprise a heavy chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:360, and a light chain variable region having an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:361.

[0241] In some embodiments, the heavy chain variable region and / or light chain variable region sequences do not vary within any of the CDR sequences provided herein. For example, in some embodiments, a degree of sequence variation (e.g., 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99%) may occur within the heavy chain variable and / or light chain variable amino acid sequence excluding any of the CDR sequences provided herein. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO:7 and a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO:8. In some embodiments, an antibody, or antigen-binding fragment thereof, comprising a heavy chain variable region having an amino acid sequence at least 90% identical to SEQ ID NO: 318 and / or a light chain variable region having an amino acid sequence at least 90% identical to SEQ ID NO: 319 is unchanged within any of the CDR sequences of Ab42 provided herein. In some embodiments, an antibody, or antigen-binding fragment thereof, comprising a heavy chain variable region having an amino acid sequence at least 90% identical to SEQ ID NO: 360 and / or a light chain variable region having an amino acid sequence at least 90% identical to SEQ ID NO: 361 is unchanged within any of the CDR sequences of Ab63 provided herein.

[0242] In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in Table 6 and / or a light chain variable domain comprising the amino acid sequence set forth in Table 6. For example, in some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 6 and / or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 7. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 6 or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 7. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 6 and a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 7.

[0243] In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 74 and / or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 75. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 74 or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 75. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 74 and a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 75.

[0244] In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 76 and / or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 77. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 76 or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 77. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 76 and a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 77.

[0245] In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 78 and / or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 79. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 78 or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 79. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 78 and a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 79.

[0246] In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 80 and / or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 81. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 80 or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 81. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 80 and a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 81.

[0247] In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 82 and / or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 83. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 82 or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 83. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 82 and a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 83.

[0248] In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 84 and / or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 85. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 84 or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 85. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 84 and a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 85.

[0249] In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 86 and / or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 87. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 86 or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 87. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 86 and a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 87.

[0250] In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 88 and / or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 89. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 88 or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 89. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 88 and a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 89.

[0251] In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 90 and / or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 91. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 90 or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 91. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 90 and a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 91.

[0252] In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 92 and / or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 93. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 92 or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 93. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 92 and a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 93.

[0253] In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 106 and / or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 107. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 106 or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 107. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 106 and a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 107.

[0254] In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 318 and / or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 319. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 318 or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 319. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 318 and a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 319.

[0255] In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 360 and / or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 361. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 360 or a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 361. In some embodiments, the antibody, or antigen-binding portion thereof, comprises a heavy chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 360 and a light chain variable domain comprising the amino acid sequence set forth in SEQ ID NO: 361.

[0256] The amino acid sequences of the heavy chain variable region (HCVR) and light chain variable region (LCVR) of antibody SR-AB2 shown in Table 5 are provided below.

[0257] SR-AB2-heavy chain variable region amino acid sequence QVQLVQSGAEVKKPGASVKVSCKASGYTFTSYGISWVRQAPGQGLEWMGWISAYNGNTNYAQKLQGRVTMTTDTSTSTAYMELRSLRSDDTAVYYCARAPLGNFDSWGQGTMVTVSS (SEQ ID NO: 7)

[0258] SR-AB2-light chain variable region amino acid sequence NFMLTQPHSVSESPGKTVTISCTRSSGSIASNYVQWYQQRPGSSPTTVIYEDNQRPSGVPDRFSGSIDSSSNSASLTISGLKTEDEADYYCQSYDSSNHPVVFGGGTKLTVL (SEQ ID NO: 8)

[0259] The amino acid sequences of the heavy chain variable region (HCVR) and light chain variable region (LCVR) of antibody SR-AB10 shown in Table 5 are provided below.

[0260] SR-AB10-heavy chain variable region amino acid sequence QLQLQESGGGVVQPGRSLRLSCAASGFTFNNYPIHWVRQAPGKGLEWVAVMSYDGINKYYADSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYYCARPRIAARRGGFDYWGQGTLVTVSS (SEQ ID NO: 88)

[0261] SR-AB10-light chain variable region amino acid sequence NFMLTQPHSVSESPGKTVTISCTRSSGNIDNNYVQWYQQRPGSSPTTVIYEDNQRPSGVPDRFSGSIDSSSNSASLTISGLKTEDEADYYCQSYDSDNQGVVFGGGTKLTVL (SEQ ID NO: 89)

[0262] The amino acid sequences of the heavy chain variable region (HCVR) and light chain variable region (LCVR) of antibody SR-AB13 shown in Table 5 are provided below.

[0263] SR-AB13-heavy chain variable region amino acid sequence QLQLQESGPGLVKPSETLSLTCTVSGGSISSSSYYWGWIRQPPGKGLEWIGSISYSGSTYYNPSLKSRVTISVDTSKNQFSLKLSSVTAADTAVYYCARDPSYDSIAGMDVWGQGTTVTVSS (SEQ ID NO: 106)

[0264] SR-AB13-light chain variable region amino acid sequence DIQLTQSPSSLSASVGDRVTITCRASQSISSYLNWYQQKPGKAPKLLIYAASNLQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQSFDFPFTFGGGTKVEIK (SEQ ID NO: 107)

[0265] The amino acid sequences of the heavy chain variable region (HCVR) and light chain variable region (LCVR) of antibody SR-AB42 shown in Table 5 are provided below.

[0266] SR-AB42-heavy chain variable region amino acid sequence QVQLVESGGGVVQPGRSLRLSCAASGFTFRSYVMHWVRQAPGKGLEWVAVISHEGSLKYYADSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYYCARPRIAARRGGFGYWGQGTLVTVSS (SEQ ID NO: 318)

[0267] 63-Light chain variable region amino acid sequence NFMLTQPHSVSESPGKTVTISCTRSSGNIDNNYVQWYQQRPGSSPTTVIYEDNQRPSGVPDRFSGSIDSSSNSASLTISGLKTEDEADYYCQSYDYDTQGVVFGGGTKLTVL (SEQ ID NO: 319)

[0268] The amino acid sequences of the heavy chain variable region (HCVR) and light chain variable region (LCVR) of antibody SR-AB63 shown in Table 5 are provided below.

[0269] SR-AB63-heavy chain variable region amino acid sequence QLQLQESGPGLVKPSETLSLTCTVSGGSIRSSSYYWGWIRQPPGKGLEWIGSISYSATTYYNPSLKSRVTISVDTSKNQFSLKLSSVTAADTAVYYCAGDPSYDSIAGMQVWGQGTTVTVSS (SEQ ID NO: 360)

[0270] SR-AB63-light chain variable region amino acid sequence DIQLTQSPSSLSASVGDRVTITCRASQSISSYLNWYQQKPGKAPKLLIYAASNLQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQSFDWPLTFGGGTKVEIK (SEQ ID NO: 361)

[0271] In some embodiments, antibodies of the invention, or antigen-binding portions thereof, that selectively bind to the LTBP1-TGFβ complex and / or the LTBP3-TGFβ complex have one or more CDR sequences substantially similar to CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and / or CDRL3. For example, the antibodies may comprise one or more CDR sequences set forth in Table 5 (SEQ ID NOS: 1-6, 94-99, or 100-105), which contain up to 6, 5, 4, 3, 2, or 1 amino acid residue variation compared to the corresponding CDR region in any one of SEQ ID NOS: 1-6, 94-99, or 100-105.

[0272] In one embodiment, the antibody, or antigen-binding fragment thereof, comprises at least three CDRs selected from the following: CDR-H1: SEQ ID NO: 1; CDR-H2: SEQ ID NO: 2; CDR-H3: SEQ ID NO: 3; CDR-L1: SEQ ID NO: 4; CDR-L2: SEQ ID NO: 5; and CDR-L3: SEQ ID NO: 6, and may comprise up to six amino acid changes in each CDR, for example, 1, 2, 3, 4, 5, or 6 amino acid changes. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises at least three CDRs selected from the following: CDR-H1: SEQ ID NO: 94; CDR-H2: SEQ ID NO: 95; CDR-H3: SEQ ID NO: 96; CDR-L1: SEQ ID NO: 97; CDR-L2: SEQ ID NO: 98; and CDR-L3: SEQ ID NO: 99, and may comprise up to six amino acid changes in each CDR, for example, 1, 2, 3, 4, 5, or 6 amino acid changes. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises at least three CDRs selected from the following: CDR-H1: SEQ ID NO: 100; CDR-H2: SEQ ID NO: 101; CDR-H3: SEQ ID NO: 102; CDR-L1: SEQ ID NO: 103; CDR-L2: SEQ ID NO: 104; and CDR-L3: SEQ ID NO: 105, and may comprise up to six amino acid changes in each CDR, for example, 1, 2, 3, 4, 5, or 6 amino acid changes. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises at least three CDRs selected from the following: CDR-H1: SEQ ID NO: 166; CDR-H2: SEQ ID NO: 167; CDR-H3: SEQ ID NO: 168; CDR-L1: SEQ ID NO: 169; CDR-L2: SEQ ID NO: 170; and CDR-L3: SEQ ID NO: 171, and may comprise up to six amino acid changes in each CDR, for example, 1, 2, 3, 4, 5, or 6 amino acid changes. In one embodiment, the antibody, or antigen-binding fragment thereof, comprises at least three CDRs selected from the following: CDR-H1: SEQ ID NO: 292; CDR-H2: SEQ ID NO: 293; CDR-H3: SEQ ID NO: 294; CDR-L1: SEQ ID NO: 295; CDR-L2: SEQ ID NO: 296; and CDR-L3: SEQ ID NO: 297, and may comprise up to six amino acid changes for each CDR, for example 1, 2, 3, 4, 5, or 6 amino acid changes.

[0273] In one aspect, the present invention provides an antibody, or antigen-binding fragment thereof, comprising a heavy chain variable region comprising CDR-H1: SEQ ID NO: 1; CDR-H2: SEQ ID NO: 2; and CDR-H3: SEQ ID NO: 3; and a light chain variable region comprising CDR-L1: SEQ ID NO: 4; CDR-L2: SEQ ID NO: 5; and CDR-L3: SEQ ID NO: 6, and may contain one or more amino acid changes, for example 1, 2, 3, 4, 5, or 6 amino acid changes, for each CDR.

[0274] In one aspect, the present invention provides an antibody, or antigen-binding fragment thereof, comprising a heavy chain variable region comprising CDR-H1: SEQ ID NO: 94; CDR-H2: SEQ ID NO: 95; and CDR-H3: SEQ ID NO: 96; and a light chain variable region comprising CDR-L1: SEQ ID NO: 97; CDR-L2: SEQ ID NO: 98; and CDR-L3: SEQ ID NO: 99, and may contain one or more amino acid changes, for example 1, 2, 3, 4, 5, or 6 amino acid changes, for each CDR.

[0275] In one aspect, the present invention provides an antibody, or antigen-binding fragment thereof, comprising a heavy chain variable region comprising CDR-H1: SEQ ID NO: 100; CDR-H2: SEQ ID NO: 101; and CDR-H3: SEQ ID NO: 102; and a light chain variable region comprising CDR-L1: SEQ ID NO: 103; CDR-L2: SEQ ID NO: 104; and CDR-L3: SEQ ID NO: 105, and may contain one or more amino acid changes, for example 1, 2, 3, 4, 5, or 6 amino acid changes, for each CDR.

[0276] In one aspect, the present invention provides an antibody, or antigen-binding fragment thereof, comprising a heavy chain variable region comprising CDR-H1: SEQ ID NO: 166; CDR-H2: SEQ ID NO: 167; and CDR-H3: SEQ ID NO: 168; and a light chain variable region comprising CDR-L1: SEQ ID NO: 169; CDR-L2: SEQ ID NO: 170; and CDR-L3: SEQ ID NO: 171, and may contain one or more amino acid changes in each CDR, for example, 1, 2, 3, 4, 5, or 6 amino acid changes. For example, if there are changes within a CDR, there may be up to one change per CDR. There may be no more than two changes across all six CDRs.

[0277] In one aspect, the present invention provides an antibody, or antigen-binding fragment thereof, comprising a heavy chain variable region comprising CDR-H1: SEQ ID NO: 292; CDR-H2: SEQ ID NO: 293; and CDR-H3: SEQ ID NO: 294; and a light chain variable region comprising CDR-L1: SEQ ID NO: 295; CDR-L2: SEQ ID NO: 296; and CDR-L3: SEQ ID NO: 297, and may contain one or more amino acid changes in each CDR, for example, 1, 2, 3, 4, 5, or 6 amino acid changes (e.g., up to 2). For example, if there are changes within a CDR, there may be up to one change per CDR. There may be no more than two changes across all six CDRs.

[0278] In one aspect, the present invention provides an antibody, or antigen-binding fragment thereof, comprising a heavy chain variable region comprising CDR-H1, CDR-H2, CDR-H3, CDR-L1, CDR-L2, and / or CDR-L3 with a particular amino acid alteration. As used herein, the phrase "amino acid alteration" or "alteration in an amino acid residue" includes amino acid substitution, addition, and / or deletion. In some embodiments, one or more alterations to an amino acid residue are present in any one of the CDRs and / or variable regions described herein. For example, in some embodiments, the one or more amino acid alterations comprise a single amino acid alteration. In some embodiments, the one or more amino acid alterations comprise up to two amino acid alterations. In some embodiments, the one or more amino acid alterations comprise up to three amino acid alterations. In some embodiments, the one or more amino acid alterations comprise up to four amino acid alterations. In some embodiments, the one or more amino acid alterations comprise up to five amino acid alterations. In some embodiments, the one or more amino acid alterations comprise up to six amino acid alterations. In some embodiments, the one or more amino acid alterations comprise up to seven amino acid alterations.

[0279] For example, in some embodiments, an antibody, or antigen-binding fragment thereof, comprises CDR-H1:SEQ ID NO:1, with the proviso that the threonine residue at position 4 of SEQ ID NO:1 may be substituted with histidine, lysine, phenylalanine, or glycine. In some embodiments, an antibody, or antigen-binding fragment thereof, comprises CDR-H1:SEQ ID NO:1, with the proviso that the serine residue at position 5 of SEQ ID NO:1 may be substituted with leucine. In some embodiments, an antibody, or antigen-binding fragment thereof, comprises CDR-H1:SEQ ID NO:1, with the proviso that the serine residue at position 9 of SEQ ID NO:1 may be substituted with alanine.

[0280] In some embodiments, the antibody, or antigen-binding fragment thereof, comprises CDR-H1: SEQ ID NO: 1, with the proviso that (i) the threonine residue at position 4 of SEQ ID NO: 1 may be substituted with histidine, lysine, phenylalanine, or glycine; (ii) the serine residue at position 5 of SEQ ID NO: 1 may be substituted with leucine; and / or (iii) the serine residue at position 9 of SEQ ID NO: 1 may be substituted with alanine.

[0281] In some embodiments, the antibody, or antigen-binding fragment thereof, comprises CDR-H2: SEQ ID NO:2, with the proviso that the serine residue at position 3 of SEQ ID NO:2 may be substituted with aspartic acid or asparagine. In some embodiments, the antibody, or antigen-binding fragment thereof, comprises CDR-H2: SEQ ID NO:2, with the proviso that the tyrosine residue at position 5 of SEQ ID NO:2 may be substituted with histidine. In some embodiments, the antibody, or antigen-binding fragment thereof, comprises CDR-H2: SEQ ID NO:2, with the proviso that the asparagine residue at position 6 of SEQ ID NO:2 may be substituted with serine. In some embodiments, the antibody, or antigen-binding fragment thereof, comprises CDR-H2: SEQ ID NO:2, with the proviso that the asparagine residue at position 8 of SEQ ID NO:2 may be substituted with phenylalanine, leucine, alanine, tyrosine, aspartic acid, or serine. In some embodiments, the antibody, or antigen-binding fragment thereof, comprises CDR-H2: SEQ ID NO:2, with the proviso that the asparagine residue at position 10 of SEQ ID NO:2 may be substituted with aspartic acid or alanine.

[0282] In some embodiments, the antibody, or antigen-binding fragment thereof, comprises CDR-H2: SEQ ID NO:2, with the proviso that (i) the serine residue at position 3 of SEQ ID NO:2 may be substituted with aspartic acid or asparagine; (ii) the tyrosine residue at position 5 of SEQ ID NO:2 may be substituted with histidine; (iii) the asparagine residue at position 6 of SEQ ID NO:2 may be substituted with serine; (iv) the asparagine residue at position 8 of SEQ ID NO:2 may be substituted with phenylalanine, leucine, alanine, tyrosine, aspartic acid, or serine; and / or (v) the asparagine residue at position 10 of SEQ ID NO:2 may be substituted with aspartic acid or alanine.

[0283] In some embodiments, the antibody, or antigen-binding fragment thereof, comprises three heavy chain CDRs and three light chain CDRs, wherein the heavy chain CDRs comprise: a) CDR-H1: SEQ ID NO: 1 under the following conditions: i. the threonine residue at position 4 of SEQ ID NO: 1 may be substituted with histidine, lysine, phenylalanine, or glycine; ii. the serine residue at position 5 of SEQ ID NO: 1 may be substituted with leucine; and / or iii. the serine residue at position 9 of SEQ ID NO: 1 may be substituted with alanine; b) CDR-H2: SEQ ID NO: 2 under the following conditions: i. the serine residue at position 3 of SEQ ID NO:2 may be substituted with aspartic acid or asparagine; ii. the tyrosine residue at position 5 of SEQ ID NO:2 may be substituted with histidine; iii. the asparagine residue at position 6 of SEQ ID NO:2 may be substituted with serine; iv. the asparagine residue at position 8 of SEQ ID NO:2 may be substituted with phenylalanine, leucine, alanine, tyrosine, aspartic acid, or serine; and / or v. The asparagine residue at position 10 of SEQ ID NO:2 may be substituted with aspartic acid or alanine; c) CDR-H3: SEQ ID NO: 3, which may contain one or more amino acid alterations.

[0284] In some embodiments, the antibody, or antigen-binding fragment thereof, further comprises a CDR-L1 set forth in SEQ ID NO: 4, which may comprise one or more amino acid alterations. In some embodiments, the antibody, or antigen-binding fragment thereof, further comprises a CDR-L2 set forth in SEQ ID NO: 5, which may comprise one or more amino acid alterations. In some embodiments, the antibody, or antigen-binding fragment thereof, further comprises a CDR-L3 set forth in SEQ ID NO: 6, which may comprise one or more amino acid alterations.

[0285] In some embodiments, the antibody, or antigen-binding fragment thereof, comprises at least three of the following six CDRs: a) CDR-H1: SEQ ID NO: 1 under the following conditions: i. the threonine residue at position 4 of SEQ ID NO: 1 may be substituted with histidine, lysine, phenylalanine, or glycine; ii. the serine residue at position 5 of SEQ ID NO: 1 may be substituted with leucine; and / or iii. the serine residue at position 9 of SEQ ID NO: 1 may be substituted with alanine; b) CDR-H2: SEQ ID NO: 2 under the following conditions: i. the serine residue at position 3 of SEQ ID NO:2 may be substituted with aspartic acid or asparagine; ii. the tyrosine residue at position 5 of SEQ ID NO:2 may be substituted with histidine; iii. the asparagine residue at position 6 of SEQ ID NO:2 may be substituted with serine; iv. the asparagine residue at position 8 of SEQ ID NO:2 may be substituted with phenylalanine, leucine, alanine, tyrosine, aspartic acid, or serine; and / or v. The asparagine residue at position 10 of SEQ ID NO:2 may be substituted with aspartic acid or alanine; c) CDR-H3: SEQ ID NO: 3, which may contain one or more amino acid alterations; d) CDR-L1: SEQ ID NO: 4, which may contain one or more amino acid alterations; e) CDR-L2: SEQ ID NO: 5, which may contain one or more amino acid alterations; and f) CDR-L3: SEQ ID NO: 6, which may contain one or more amino acid alterations.

[0286] In some embodiments, the antibody, or antigen-binding fragment thereof, specifically binds to the human LTBP1-proTGFβ1 complex and / or the human LTBP3-proTGFβ1 complex, but does not bind to the human GARP-proTGFβ1 complex. In some embodiments, the antibody, or antigen-binding fragment thereof, does not bind to the human GARP-proTGFβ1 complex. In some embodiments, the antibody, or antigen-binding fragment thereof, does not bind to mature TGFβ1, mature TGFβ2, or mature TGFβ3.

[0287] In one particular embodiment, the present invention provides an isolated antibody that specifically binds to human LTBP1-proTGFβ1 complex and / or human LTBP3-proTGFβ1 complex, but does not bind to human GARP-proTGFβ1 complex or human LRRC33-proTGFβ1 complex; wherein the antibody does not bind to mature TGFβ1, mature TGFβ2, or mature TGFβ3; and wherein the antibody is a fully human or humanized antibody or fragment thereof, and wherein the antibody comprises at least three of the following six CDRs: a) CDR-H1: SEQ ID NO: 1 under the following conditions: i. the threonine residue at position 4 of SEQ ID NO: 1 may be substituted with histidine, lysine, phenylalanine, or glycine; ii. the serine residue at position 5 of SEQ ID NO: 1 may be substituted with leucine; and / or iii. the serine residue at position 9 of SEQ ID NO: 1 may be substituted with alanine; b) CDR-H2: SEQ ID NO: 2 under the following conditions: i. the serine residue at position 3 of SEQ ID NO:2 may be substituted with aspartic acid or asparagine; ii. the tyrosine residue at position 5 of SEQ ID NO:2 may be substituted with histidine; iii. the asparagine residue at position 6 of SEQ ID NO:2 may be substituted with serine; iv. the asparagine residue at position 8 of SEQ ID NO:2 may be substituted with phenylalanine, leucine, alanine, tyrosine, aspartic acid, or serine; and / or v. The asparagine residue at position 10 of SEQ ID NO:2 may be substituted with aspartic acid or alanine; c) CDR-H3: SEQ ID NO: 3, which may contain one or more amino acid alterations; d) CDR-L1: SEQ ID NO: 4, which may contain one or more amino acid alterations; e) CDR-L2: SEQ ID NO: 5, which may contain one or more amino acid alterations; and f) CDR-L3: SEQ ID NO: 6, which may contain one or more amino acid alterations.

[0288] In some embodiments, such antibodies have a K of <100 nM as measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or such antibodies have a K of <100 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). D In some embodiments, such antibodies bind to the human LTBP3-proTGFβ1 complex with a K of <50 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or such antibodies have a K of <50 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). D In some embodiments, such antibodies bind to the human LTBP3-proTGFβ1 complex with a K of <25 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). Dand / or such antibodies have a K of <25 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). D In some embodiments, such antibodies bind to the human LTBP3-proTGFβ1 complex with a K of <10 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or such antibodies have a K of <10 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). D It binds to the human LTBP3-proTGFβ1 complex.

[0289] In another embodiment, such antibodies are cross-reactive with mouse LTBP1-proTGFβ1. In some embodiments, such antibodies are also cross-reactive with mouse LTBP3-proTGFβ1. In some embodiments, such antibodies have a K of <100 nM as measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or the antibody has a K of <100 nM when measured in an appropriate in vitro binding assay, such as biolayer interferometry (BLI). D In some embodiments, such antibodies bind to the mouse LTBP3-proTGFβ1 complex with a K of <50 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or such antibodies have a K of <50 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). D In some embodiments, such antibodies bind to the mouse LTBP3-proTGFβ1 complex with a K of <25 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). Dand / or the antibody has a K of <25 nM when measured in an appropriate in vitro binding assay, such as biolayer interferometry (BLI). D In some embodiments, such antibodies bind to the mouse LTBP3-proTGFβ1 complex with a K of <10 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or the antibody has a K of <10 nM when measured in an appropriate in vitro binding assay, such as biolayer interferometry (BLI). D It binds to the mouse LTBP3-proTGFβ1 complex.

[0290] In another embodiment, such antibodies do not bind to human GARP-proTGFβ1. In a preferred embodiment, such context-selective antibodies are isoform-specific in that they selectively bind and inhibit activation of TGFβ1 in association with LTBP1 / 3 and do not bind to human GARP-proTGFβ1.

[0291] In another aspect, the antibody, or antigen-binding fragment thereof, comprises CDR-H1: SEQ ID NO: 94, with the proviso that the threonine residue at position 2 of SEQ ID NO: 94 may be substituted with alanine. In some embodiments, the antibody, or antigen-binding fragment thereof, comprises CDR-H1: SEQ ID NO: 94, with the proviso that the asparagine residue at position 4 of SEQ ID NO: 94 may be substituted with alanine, tyrosine, aspartic acid, serine, arginine, or histidine. In some embodiments, the antibody, or antigen-binding fragment thereof, comprises CDR-H1: SEQ ID NO: 94, with the proviso that the asparagine residue at position 5 of SEQ ID NO: 94 may be substituted with glutamine, serine, glycine, lysine, glutamic acid, arginine, or histidine. In some embodiments, the antibody, or antigen-binding fragment thereof, comprises CDR-H1: SEQ ID NO: 94, with the proviso that the tyrosine residue at position 6 of SEQ ID NO: 94 may be substituted with arginine. In some embodiments, the antibody, or antigen-binding fragment thereof, comprises CDR-H1: SEQ ID NO: 94, with the proviso that the proline residue at position 7 of SEQ ID NO: 94 may be substituted with glycine, alanine, leucine, serine, asparagine, valine, aspartic acid, or glutamine. In some embodiments, the antibody, or antigen-binding fragment thereof, comprises CDR-H1: SEQ ID NO: 94, with the proviso that the isoleucine residue at position 8 of SEQ ID NO: 94 may be substituted with methionine or leucine. In some embodiments, the antibody, or antigen-binding fragment thereof, comprises CDR-H1: SEQ ID NO: 94, with the proviso that the histidine residue at position 9 of SEQ ID NO: 94 may be substituted with phenylalanine, tyrosine, asparagine, or serine.

[0292] In some embodiments, the antibody, or antigen-binding fragment thereof, comprises: (i) the threonine residue at position 2 of SEQ ID NO:94 may be substituted with alanine; (ii) the asparagine residue at position 4 of SEQ ID NO:94 may be substituted with alanine, tyrosine, aspartic acid, serine, arginine, or histidine; (iii) the asparagine residue at position 5 of SEQ ID NO:94 may be substituted with glutamine, serine, glycine, lysine, glutamic acid, arginine, or histidine; or (iv) the tyrosine residue at position 6 of SEQ ID NO:94. (v) the proline residue at position 7 of SEQ ID NO: 94 may be substituted with glycine, alanine, leucine, serine, asparagine, valine, aspartic acid, or glutamine; (vi) the isoleucine residue at position 8 of SEQ ID NO: 94 may be substituted with methionine or leucine; and / or (vii) the histidine residue at position 9 of SEQ ID NO: 94 may be substituted with phenylalanine, tyrosine, asparagine, or serine.

[0293] In some embodiments, the antibody, or antigen-binding fragment thereof, comprises three heavy chain CDRs and three light chain CDRs, wherein the heavy chain CDRs comprise: a) CDR-H1: SEQ ID NO: 94 under the following conditions: i. the threonine residue at position 2 of SEQ ID NO: 94 may be substituted with alanine; ii. the asparagine residue at position 4 of SEQ ID NO: 94 may be substituted with alanine, tyrosine, aspartic acid, serine, arginine, or histidine; iii. the asparagine residue at position 5 of SEQ ID NO: 94 may be substituted with glutamine, serine, glycine, lysine, glutamic acid, arginine, or histidine; iv. The tyrosine residue at position 6 of SEQ ID NO: 94 may be substituted with arginine; v. The proline residue at position 7 of SEQ ID NO: 94 may be substituted with glycine, alanine, leucine, serine, asparagine, valine, aspartic acid, or glutamine; vi. the isoleucine residue at position 8 of SEQ ID NO: 94 may be substituted with methionine or leucine; and / or vii. the histidine residue at position 9 of SEQ ID NO: 94 may be substituted with phenylalanine, tyrosine, asparagine, or serine; b) CDR-H2: SEQ ID NO: 95, which may contain one or more amino acid alterations; and c) CDR-H3: SEQ ID NO: 96, which may contain one or more amino acid alterations.

[0294] In some embodiments, the antibody, or antigen-binding fragment thereof, further comprises CDR-L1 as set forth in SEQ ID NO: 97, which may comprise one or more amino acid alterations. In some embodiments, the antibody, or antigen-binding fragment thereof, further comprises CDR-L2 as set forth in SEQ ID NO: 98, which may comprise one or more amino acid alterations. In some embodiments, the antibody, or antigen-binding fragment thereof, further comprises CDR-L3 as set forth in SEQ ID NO: 99, which may comprise one or more amino acid alterations.

[0295] In some embodiments, the antibody, or antigen-binding fragment thereof, comprises at least three of the following six CDRs: a) CDR-H1: SEQ ID NO: 94 under the following conditions: i. the threonine residue at position 2 of SEQ ID NO: 94 may be substituted with alanine; ii. the asparagine residue at position 4 of SEQ ID NO: 94 may be substituted with alanine, tyrosine, aspartic acid, serine, arginine, or histidine; iii. the asparagine residue at position 5 of SEQ ID NO: 94 may be substituted with glutamine, serine, glycine, lysine, glutamic acid, arginine, or histidine; iv. The tyrosine residue at position 6 of SEQ ID NO: 94 may be substituted with arginine; v. The proline residue at position 7 of SEQ ID NO: 94 may be substituted with glycine, alanine, leucine, serine, asparagine, valine, aspartic acid, or glutamine; vi. the isoleucine residue at position 8 of SEQ ID NO: 94 may be substituted with methionine or leucine; and / or vii. the histidine residue at position 9 of SEQ ID NO: 94 may be substituted with phenylalanine, tyrosine, asparagine, or serine; b) CDR-H2: SEQ ID NO: 95, which may contain one or more amino acid alterations; c) CDR-H3: SEQ ID NO: 96, which may contain one or more amino acid alterations; d) CDR-L1: SEQ ID NO: 97, which may contain one or more amino acid alterations; e) CDR-L2: SEQ ID NO: 98, which may contain one or more amino acid alterations; and f) CDR-L3: SEQ ID NO: 99, which may contain one or more amino acid alterations.

[0296] In some embodiments, the antibody, or antigen-binding fragment thereof, specifically binds to the human LTBP1-proTGFβ1 complex and / or the human LTBP3-proTGFβ1 complex, but does not bind to the human GARP-proTGFβ1 complex. In some embodiments, the antibody, or antigen-binding fragment thereof, does not bind to the human GARP-proTGFβ1 complex. In some embodiments, the antibody, or antigen-binding fragment thereof, does not bind to mature TGFβ1, mature TGFβ2, or mature TGFβ3.

[0297] In one particular embodiment, the antibody, or antigen-binding fragment thereof, specifically binds to the human LTBP1-proTGFβ1 complex and / or the human LTBP3-proTGFβ1 complex and does not bind to the human GARP-proTGFβ1 complex; wherein the antibody does not bind to mature TGFβ1, mature TGFβ2, or mature TGFβ3; and wherein the antibody is a fully human or humanized antibody or fragment thereof, and wherein the antibody comprises at least three of the following six CDRs: a) CDR-H1: SEQ ID NO: 94 under the following conditions: i. the threonine residue at position 2 of SEQ ID NO: 94 may be substituted with alanine; ii. the asparagine residue at position 4 of SEQ ID NO: 94 may be substituted with alanine, tyrosine, aspartic acid, serine, arginine, or histidine; iii. the asparagine residue at position 5 of SEQ ID NO: 94 may be substituted with glutamine, serine, glycine, lysine, glutamic acid, arginine, or histidine; iv. The tyrosine residue at position 6 of SEQ ID NO: 94 may be substituted with arginine; v. The proline residue at position 7 of SEQ ID NO: 94 may be substituted with glycine, alanine, leucine, serine, asparagine, valine, aspartic acid, or glutamine; vi. the isoleucine residue at position 8 of SEQ ID NO: 94 may be substituted with methionine or leucine; and / or vii. the histidine residue at position 9 of SEQ ID NO: 94 may be substituted with phenylalanine, tyrosine, asparagine, or serine; b) CDR-H2: SEQ ID NO: 95, which may contain one or more amino acid alterations; c) CDR-H3: SEQ ID NO: 96, which may contain one or more amino acid alterations; d) CDR-L1: SEQ ID NO: 97, which may contain one or more amino acid alterations; e) CDR-L2: SEQ ID NO: 98, which may contain one or more amino acid alterations; and f) CDR-L3: SEQ ID NO: 99, which may contain one or more amino acid alterations.

[0298] In some embodiments, such antibodies have a K of <100 nM as measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or such antibodies have a K of <100 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). DIn some embodiments, such antibodies bind to the human LTBP3-proTGFβ1 complex with a K of <50 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or such antibodies have a K of <50 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). D In some embodiments, such antibodies bind to the human LTBP3-proTGFβ1 complex with a K of <25 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or such antibodies have a K of <25 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). D In some embodiments, such antibodies bind to the human LTBP3-proTGFβ1 complex with a K of <10 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or such antibodies have a K of <10 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). D It binds to the human LTBP3-proTGFβ1 complex.

[0299] In another embodiment, such antibodies are cross-reactive with mouse LTBP1-proTGFβ1. In some embodiments, such antibodies are also cross-reactive with mouse LTBP3-proTGFβ1. In some embodiments, such antibodies have a K of <100 nM as measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or the antibody has a K of <100 nM when measured in an appropriate in vitro binding assay, such as biolayer interferometry (BLI). DIn some embodiments, such antibodies bind to the mouse LTBP3-proTGFβ1 complex with a K of <50 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or the antibody has a K of <50 nM when measured in an appropriate in vitro binding assay, such as biolayer interferometry (BLI). D In some embodiments, such antibodies bind to the mouse LTBP3-proTGFβ1 complex with a K of <25 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or the antibody has a K of <25 nM when measured in an appropriate in vitro binding assay, such as biolayer interferometry (BLI). D In some embodiments, such antibodies bind to the mouse LTBP3-proTGFβ1 complex with a K of <10 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or the antibody has a K of <10 nM when measured in an appropriate in vitro binding assay, such as biolayer interferometry (BLI). D It binds to the mouse LTBP3-proTGFβ1 complex.

[0300] In another embodiment, such antibodies do not bind to human GARP-proTGFβ1. In a preferred embodiment, such context-selective antibodies are also isoform-specific, in that they selectively bind to and inhibit activation of TGFβ1 in association with LTBP1 / 3.

[0301] In another aspect, the antibody, or antigen-binding fragment thereof, comprises a CDR-H1 comprising the amino acid sequence FTF(X1)(X2)YVMH, where X1 may be S or R and X2 may be G or S. In some embodiments, X1 is S. In some embodiments, X1 is R. In some embodiments, X2 is G. In some embodiments, X2 is S.

[0302] In some embodiments, the antibody, or antigen-binding fragment thereof, comprises a CDR-H2 comprising the amino acid sequence (X1)ISHEG(X2)(X3)KYYADSVKG, where X1 may be V or S, X2 may be S or G, and X3 may be F or L. In some embodiments, X1 is V. In some embodiments, X1 is S. In some embodiments, X2 is S. In some embodiments, X2 is G. In some embodiments, X3 is F. In some embodiments, X3 is L.

[0303] In some embodiments, the antibody, or antigen-binding fragment thereof, comprises a CDR-H3 comprising the amino acid sequence (X1)(X2)P(X3)(X4)(X5)(X6)RRGG(X7)(X8)(X9), where X1 can be A or V; X2 can be R, V, G, or K; X3 can be R, H, or L; X4 can be I, V, or G; X5 can be A, S, or L; X6 can be A or V; X7 can be F or Y; X8 can be D, G, R, or S; and X9 can be Y, G, R, L, V, A, or K. In some embodiments, X1 is A. In some embodiments, X1 is V. In some embodiments, X2 is R. In some embodiments, X2 is V. In some embodiments, X2 is G. In some embodiments, X2 is K. In some embodiments, X3 is R. In some embodiments, X3 is H. In some embodiments, X3 is L. In some embodiments, X4 is I. In some embodiments, X4 is V. In some embodiments, X4 is G. In some embodiments, X5 is A. In some embodiments, X5 is S. In some embodiments, X5 is L. In some embodiments, X6 is A. In some embodiments, X6 is V. In some embodiments, X7 is F. In some embodiments, X7 is Y. In some embodiments, X8 is D. In some embodiments, X8 is G. In some embodiments, X8 is R. In some embodiments, X8 is S. In some embodiments, X9 is Y. In some embodiments, X9 is G. In some embodiments, X9 is R. In some embodiments, X9 is L. In some embodiments, X9 is V. In some embodiments, X9 is A. In some embodiments, X9 is K.

[0304] In some embodiments, the antibody, or antigen-binding fragment thereof, comprises three heavy chain CDRs and three light chain CDRs, wherein the heavy chain CDRs comprise: a) CDR-H1 comprising the amino acid sequence FTF(X1)(X2)YVMH, where X1 can be S or R and X2 can be G or S; b) a CDR-H2 comprising the amino acid sequence (X1)ISHEG(X2)(X3)KYYADSVKG, wherein X1 can be V or S, X2 can be S or G, and X3 can be F or L; and c) A CDR-H3 comprising the amino acid sequence (X1)(X2)P(X3)(X4)(X5)(X6)RRGG(X7)(X8)(X9), wherein X1 can be A or V; X2 can be R, V, G, or K; X3 can be R, H, or L; X4 can be I, V, or G; X5 can be A, S, or L; X6 can be A or V; X7 can be F or Y; X8 can be D, G, R, or S; and X9 can be Y, G, R, L, V, A, or K.

[0305] In some embodiments, the antibody, or antigen-binding fragment thereof, further comprises CDR-L1 set forth in SEQ ID NO: 97, which may comprise one or more amino acid alterations. In some embodiments, the antibody, or antigen-binding fragment thereof, further comprises CDR-L2 set forth in SEQ ID NO: 98, which may comprise one or more amino acid alterations. In some embodiments, the antibody, or antigen-binding fragment thereof, further comprises CDR-L3 set forth in SEQ ID NO: 99, which may comprise one or more amino acid alterations.

[0306] In some embodiments, the antibody, or antigen-binding fragment, comprises at least three of the following six CDRs: a) CDR-H1 comprising the amino acid sequence FTF(X1)(X2)YVMH, where X1 can be S or R and X2 can be G or S; b) CDR-H2 comprising the amino acid sequence (X1)ISHEG(X2)(X3)KYYADSVKG, where X1 can be V or S, X2 can be S or G, and X3 can be F or L; c) a CDR-H3 comprising the amino acid sequence (X1)(X2)P(X3)(X4)(X5)(X6)RRGG(X7)(X8)(X9), wherein X1 can be A or V, X2 can be R, V, G, or K, X3 can be R, H, or L, X4 can be I, V, or G, X5 can be A, S, or L, X6 can be A or V, X7 can be F or Y, X8 can be D, G, R, or S, and X9 can be Y, G, R, L, V, A, or K; d) CDR-L1 as set forth in SEQ ID NO: 97, which may contain one or more amino acid alterations; e) CDR-L2 as set forth in SEQ ID NO: 98, which may contain one or more amino acid alterations; and f) CDR-L3 as set forth in SEQ ID NO: 99, which may contain one or more amino acid alterations.

[0307] In some embodiments, the antibody, or antigen-binding fragment thereof, specifically binds to the human LTBP1-proTGFβ1 complex and / or the human LTBP3-proTGFβ1 complex, but does not bind to the human GARP-proTGFβ1 complex. In some embodiments, the antibody, or antigen-binding fragment thereof, does not bind to the human GARP-proTGFβ1 complex. In some embodiments, the antibody, or antigen-binding fragment thereof, does not bind to mature TGFβ1, mature TGFβ2, or mature TGFβ3.

[0308] In one particular embodiment, the antibody, or antigen-binding fragment, specifically binds to the human LTBP1-proTGFβ1 complex and / or the human LTBP3-proTGFβ1 complex and does not bind to the human GARP-proTGFβ1 complex; wherein the antibody does not bind to mature TGFβ1, mature TGFβ2, or mature TGFβ3; and wherein the antibody is a fully human or humanized antibody or fragment thereof, and wherein the antibody comprises at least three of the following six CDRs: a) CDR-H1 comprising the amino acid sequence FTF(X1)(X2)YVMH, where X1 can be S or R and X2 can be G or S; b) CDR-H2 comprising the amino acid sequence (X1)ISHEG(X2)(X3)KYYADSVKG, where X1 can be V or S, X2 can be S or G, and X3 can be F or L; c) a CDR-H3 comprising the amino acid sequence (X1)(X2)P(X3)(X4)(X5)(X6)RRGG(X7)(X8)(X9), wherein X1 can be A or V, X2 can be R, V, G, or K, X3 can be R, H, or L, X4 can be I, V, or G, X5 can be A, S, or L, X6 can be A or V, X7 can be F or Y, X8 can be D, G, R, or S, and X9 can be Y, G, R, L, V, A, or K; d) CDR-L1 as set forth in SEQ ID NO: 97, which may contain one or more amino acid alterations; e) CDR-L2 as set forth in SEQ ID NO: 98, which may contain one or more amino acid alterations; and f) CDR-L3 as set forth in SEQ ID NO: 99, which may contain one or more amino acid alterations.

[0309] In some embodiments, such antibodies have a K of <100 nM as measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). Dand / or such antibodies have a K of <100 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). D In some embodiments, such antibodies bind to the human LTBP3-proTGFβ1 complex with a K of <50 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or such antibodies have a K of <50 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). D In some embodiments, such antibodies bind to the human LTBP3-proTGFβ1 complex with a K of <25 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or such antibodies have a K of <25 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). D In some embodiments, such antibodies bind to the human LTBP3-proTGFβ1 complex with a K of <10 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or such antibodies have a K of <10 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). D It binds to the human LTBP3-proTGFβ1 complex.

[0310] In another embodiment, such antibodies are cross-reactive with mouse LTBP1-proTGFβ1. In some embodiments, such antibodies are also cross-reactive with mouse LTBP3-proTGFβ1. In some embodiments, such antibodies have a K of <100 nM as measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). Dand / or the antibody has a K of <100 nM when measured in an appropriate in vitro binding assay, such as biolayer interferometry (BLI). D In some embodiments, such antibodies bind to the mouse LTBP3-proTGFβ1 complex with a K of <50 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or the antibody has a K of <50 nM when measured in an appropriate in vitro binding assay, such as biolayer interferometry (BLI). D In some embodiments, such antibodies bind to the mouse LTBP3-proTGFβ1 complex with a K of <25 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or the antibody has a K of <25 nM when measured in an appropriate in vitro binding assay, such as biolayer interferometry (BLI). D In some embodiments, such antibodies bind to the mouse LTBP3-proTGFβ1 complex with a K of <10 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or the antibody has a K of <10 nM when measured in an appropriate in vitro binding assay, such as biolayer interferometry (BLI). D It binds to the mouse LTBP3-proTGFβ1 complex.

[0311] In another embodiment, such antibodies do not bind to human GARP-proTGFβ1. In a preferred embodiment, such context-selective antibodies are also isoform-specific, in that they selectively bind to and inhibit activation of TGFβ1 in association with LTBP1 / 3.

[0312] In another aspect, the antibody, or antigen-binding fragment thereof, comprises a CDR-H1 comprising the amino acid sequence FTF(X1)(X2)YVMH, where X1 may be S or R and X2 may be G or S. In some embodiments, X1 is S. In some embodiments, X1 is R. In some embodiments, X2 is G. In some embodiments, X2 is S.

[0313] In some embodiments, the antibody, or antigen-binding fragment thereof, comprises a CDR-H2 comprising the amino acid sequence (X1)ISHEGS(X2)KYYADSVKG, where X1 may be V or S; and X2 may be F or L. In some embodiments, X1 is V. In some embodiments, X1 is S. In some embodiments, X3 is F. In some embodiments, X3 is L.

[0314] In some embodiments, the antibody, or antigen-binding fragment thereof, comprises a CDR-H3 comprising the amino acid sequence A(X1)PRI(X2)ARRGGFGY, where X1 can be R or V; and X2 can be A or L. In some embodiments, X1 is R. In some embodiments, X1 is V. In some embodiments, X2 is A. In some embodiments, X2 is L.

[0315] In some embodiments, the antibody, or antigen-binding fragment thereof, comprises three heavy chain CDRs and three light chain CDRs, wherein the heavy chain CDRs comprise: a) CDR-H1 comprising the amino acid sequence FTF(X1)(X2)YVMH, where X1 can be S or R and X2 can be G or S; b) a CDR-H2 comprising the amino acid sequence (X1)ISHEGS(X2)KYYADSVKG, where X1 can be V or S; X2 can be F or L; and c) A CDR-H3 comprising the amino acid sequence A(X1)PRI(X2)ARRGGFGY, where X1 can be R or V; X2 can be A or L.

[0316] In some embodiments, the antibody, or antigen-binding fragment thereof, further comprises CDR-L1 set forth in SEQ ID NO: 97, which may comprise one or more amino acid alterations. In some embodiments, the antibody, or antigen-binding fragment thereof, further comprises CDR-L2 set forth in SEQ ID NO: 98, which may comprise one or more amino acid alterations. In some embodiments, the antibody, or antigen-binding fragment thereof, further comprises CDR-L3 set forth in SEQ ID NO: 99, which may comprise one or more amino acid alterations.

[0317] In some embodiments, the antibody, or antigen-binding fragment, comprises at least three of the following six CDRs: a) CDR-H1 comprising the amino acid sequence FTF(X1)(X2)YVMH, where X1 can be S or R and X2 can be G or S; b) CDR-H2 comprising the amino acid sequence (X1)ISHEGS(X2)KYYADSVKG, where X1 can be V or S; and X2 can be F or L; c) a CDR- comprising the amino acid sequence A(X1)PRI(X2)ARRGGFGY, where X1 may be R or V; and X2 may be A or L; d) CDR-L1 as set forth in SEQ ID NO: 97, which may contain one or more amino acid alterations; e) CDR-L2 as set forth in SEQ ID NO: 98, which may contain one or more amino acid alterations; and f) CDR-L3 as set forth in SEQ ID NO: 99, which may contain one or more amino acid alterations.

[0318] In some embodiments, the antibody, or antigen-binding fragment thereof, specifically binds to the human LTBP1-proTGFβ1 complex and / or the human LTBP3-proTGFβ1 complex, but does not bind to the human GARP-proTGFβ1 complex. In some embodiments, the antibody, or antigen-binding fragment thereof, does not bind to the human GARP-proTGFβ1 complex. In some embodiments, the antibody, or antigen-binding fragment thereof, does not bind to mature TGFβ1, mature TGFβ2, or mature TGFβ3.

[0319] In one particular embodiment, the antibody, or antigen-binding fragment thereof, specifically binds to the human LTBP1-proTGFβ1 complex and / or the human LTBP3-proTGFβ1 complex and does not bind to the human GARP-proTGFβ1 complex; wherein the antibody does not bind to mature TGFβ1, mature TGFβ2, or mature TGFβ3; and wherein the antibody is a fully human or humanized antibody or fragment thereof, and wherein the antibody comprises at least three of the following six CDRs: a) CDR-H1 comprising the amino acid sequence FTF(X1)(X2)YVMH, where X1 can be S or R and X2 can be G or S; b) CDR-H2 comprising the amino acid sequence (X1)ISHEGS(X2)KYYADSVKG, where X1 is V or S; and X2 is F or L; c) a CDR-H3 comprising the amino acid sequence A(X1)PRI(X2)ARRGGFGY, where X1 can be R or V; and X2 can be A or L; d) CDR-L1 as set forth in SEQ ID NO: 97, which may contain one or more amino acid alterations; e) CDR-L2 as set forth in SEQ ID NO: 98, which may contain one or more amino acid alterations; and f) CDR-L3 as set forth in SEQ ID NO: 99, which may contain one or more amino acid alterations.

[0320] In some embodiments, such antibodies have a K of <100 nM as measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or such antibodies have a K of <100 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). D In some embodiments, such antibodies bind to the human LTBP3-proTGFβ1 complex with a K of <50 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or such antibodies have a K of <50 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). D In some embodiments, such antibodies bind to the human LTBP3-proTGFβ1 complex with a K of <25 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or such antibodies have a K of <25 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). D In some embodiments, such antibodies bind to the human LTBP3-proTGFβ1 complex with a K of <10 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or such antibodies have a K of <10 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). D It binds to the human LTBP3-proTGFβ1 complex.

[0321] In another embodiment, such antibodies are cross-reactive with mouse LTBP1-proTGFβ1. In some embodiments, such antibodies are also cross-reactive with mouse LTBP3-proTGFβ1. In some embodiments, such antibodies have a K of <100 nM as measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or the antibody has a K of <100 nM when measured in an appropriate in vitro binding assay, such as biolayer interferometry (BLI). D In some embodiments, such antibodies bind to the mouse LTBP3-proTGFβ1 complex with a K of <50 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or the antibody has a K of <50 nM when measured in an appropriate in vitro binding assay, such as biolayer interferometry (BLI). D In some embodiments, such antibodies bind to the mouse LTBP3-proTGFβ1 complex with a K of <25 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or the antibody has a K of <25 nM when measured in an appropriate in vitro binding assay, such as biolayer interferometry (BLI). D In some embodiments, such antibodies bind to the mouse LTBP3-proTGFβ1 complex with a K of <10 nM as measured by a suitable in vitro binding assay, such as biolayer interferometry (BLI). D and / or the antibody has a K of <10 nM when measured in an appropriate in vitro binding assay, such as biolayer interferometry (BLI). D It binds to the mouse LTBP3-proTGFβ1 complex.

[0322] In another embodiment, such antibodies do not bind to human GARP-proTGFβ1. In a preferred embodiment, such context-selective antibodies are also isoform-specific, in that they selectively bind to and inhibit activation of TGFβ1 in association with LTBP1 / 3.

[0323] In another aspect, the antibody, or antigen-binding fragment thereof, comprises CDR-H1: SEQ ID NO: 100, with the proviso that the serine residue at position 4 of SEQ ID NO: 100 may be substituted with histidine. In some embodiments, the antibody, or antigen-binding fragment thereof, comprises CDR-H1: SEQ ID NO: 100, with the proviso that the serine residue at position 7 of SEQ ID NO: 100 may be substituted with alanine or glycine. In some embodiments, the antibody, or antigen-binding fragment thereof, comprises CDR-H1: SEQ ID NO: 100, with the proviso that the glycine residue at position 11 of SEQ ID NO: 100 may be substituted with threonine, serine, histidine, leucine, isoleucine, asparagine, valine, or alanine.

[0324] In some embodiments, the antibody, or antigen-binding fragment thereof, comprises CDR-H1: SEQ ID NO: 100, with the proviso that (i) the serine residue at position 4 of SEQ ID NO: 100 may be substituted with histidine; (ii) the serine residue at position 7 of SEQ ID NO: 100 may be substituted with alanine or glycine; and / or (iii) the glycine residue at position 11 of SEQ ID NO: 100 may be substituted with threonine, serine, histidine, leucine, isoleucine, asparagine, valine, or alanine.

[0325] In some embodiments, the antibody, or antigen-binding fragment thereof, comprises CDR-H1: SEQ ID NO: 101, with the proviso that the serine residue at position 3 of SEQ ID NO: 101 may be substituted with alanine. In some embodiments, the antibody, or antigen-binding fragment thereof, comprises CDR-H1: SEQ ID NO: 101, with the proviso that the glycine residue at position 6 of SEQ ID NO: 101 may be substituted with alanine or serine. In some embodiments, the antibody, or antigen-binding fragment thereof, comprises CDR-H1: SEQ ID NO: 101, with the proviso that the serine residue at position 7 of SEQ ID NO: 101 may be substituted with threonine.

[0326] In some embodiments, the antibody, or antigen-binding fragment thereof, comprises CDR-H1: SEQ ID NO: 101, with the proviso that (i) the serine residue at position 3 of SEQ ID NO: 101 may be substituted with alanine; (ii) the glycine residue at position 6 of SEQ ID NO: 101 may be substituted with alanine or serine; and / or (iii) the serine residue at position 7 of SEQ ID NO: 101 may be substituted with threonine.

[0327] In some embodiments, the antibody, or antigen-binding fragment thereof, comprises three heavy chain CDRs and three light chain CDRs, wherein the heavy chain CDRs comprise: a) CDR-H1: SEQ ID NO: 100 under the following conditions: i. the serine residue at position 4 of SEQ ID NO: 100 may be substituted with histidine; ii. the serine residue at position 7 of SEQ ID NO: 100 may be substituted with alanine or glycine; and / or iii. the glycine residue at position 11 of SEQ ID NO: 100 may be substituted with threonine, serine, histidine, leucine, isoleucine, asparagine, valine, or alanine; b) CDR-H2: SEQ ID NO: 101 under the following conditions: i. the serine residue at position 3 of SEQ ID NO: 101 may be substituted with alanine; ii. the glycine residue at position 6 of SEQ ID NO: 101 may be substituted with alanine or serine; and / or iii. the serine residue at position 7 of SEQ ID NO: 101 may be substituted with threonine; and c) CDR-H3: SEQ ID NO: 102, which may contain up to 3, 4, 5 or 6 amino acid changes.

[0328] In some embodiments, the antibody, or antigen-binding fragment thereof, further comprises a CDR-L1 set forth in SEQ ID NO: 103, which may comprise one or more amino acid alterations. In some embodiments, the antibody, or antigen-binding fragment thereof, further comprises a CDR-L2 set forth in SEQ ID NO: 104, which may comprise one or more amino acid alterations. In some embodiments, the antibody, or antigen-binding fragment thereof, further comprises a CDR-L3 set forth in SEQ ID NO: 105, which may comprise one or more amino acid alterations.

[0329] In some embodiments, the antibody, or antigen-binding fragment thereof, comprises at least three of the following six CDRs: a) CDR-H1: SEQ ID NO: 100 under the following conditions: i. the serine residue at position 4 of SEQ ID NO: 100 may be substituted with histidine; ii. the serine residue at position 7 of SEQ ID NO: 100 may be substituted with alanine or glycine; and / or iii. the glycine residue at position 11 of SEQ ID NO: 100 may be substituted with threonine, serine, histidine, leucine, isoleucine, asparagine, valine, or alanine; b) CDR-H2: SEQ ID NO: 101 under the following conditions: i. the serine residue at position 3 of SEQ ID NO: 101 may be substituted with alanine; ii. the glycine residue at position 6 of SEQ ID NO: 101 may be substituted with alanine or serine; and / or iii. the serine residue at position 7 of SEQ ID NO: 101 may be substituted with threonine; and c) CDR-H3: SEQ ID NO: 102, which may contain one or more amino acid alterations. d) CDR-L1: SEQ ID NO: 103, which may contain one or more amino acid alterations; e) CDR-L2: SEQ ID NO: 104, which may contain one or more amino acid alterations; and f) CDR-L3: SEQ ID NO: 105, which may contain one or more amino acid alterations.

[0330] In some embodiments, the antibody or antigen-binding fragment specifically binds to the human LTBP1-proTGFβ1 complex and / or the human LTBP3-proTGFβ1 complex, but does not bind to the human GARP-proTGFβ1 complex. In some embodiments, the antibody or antigen-binding fragment does not bind to the human GARP-proTGFβ1 complex. In some embodiments, the antibody or antigen-binding fragment does not bind to mature TGFβ1, mature TGFβ2, or mature TGFβ3.

[0331] In one particular embodiment, the antibody, or antigen-binding fragment, specifically binds to the human LTBP1-proTGFβ1 complex and / or the human LTBP3-proTGFβ1 complex and does not bind to the human GARP-proTGFβ1 complex; wherein the antibody does not bind to mature TGFβ1, mature TGFβ2, or mature TGFβ3; and wherein the antibody is a fully human or humanized antibody or fragment thereof, and wherein the antibody comprises at least three of the following six CDRs: a) CDR-H1: SEQ ID NO: 100 under the following conditions: i. the serine residue at position 4 of SEQ ID NO: 100 may be substituted with histidine; ii. the serine residue at position 7 of SEQ ID NO: 100 may be substituted with alanine or glycine; and / or iii. the glycine residue at position 11 of SEQ ID NO: 100 may be substituted with threonine, serine, histidine, leucine, isoleucine, asparagine, valine, or alanine; b) CDR-H2: SEQ ID NO: 101 under the following conditions: i. the serine residue at position 3 of SEQ ID NO: 101 may be substituted with alanine; ii. the glycine residue at position 6 of SEQ ID NO: 101 may be substituted with alanine or serine; and / or iii. The serine residue at position 7 of SEQ ID NO: 101 may be substituted with threonine; c) CDR-H3: SEQ ID NO: 102, which may contain one or more amino acid alterations; d) CDR-L1: SEQ ID NO: 103, which may contain one or more amino acid alterations; e) CDR-L2: SEQ ID NO: 104, which may contain one or more amino acid alterations; and f) CDR-L3: SEQ ID NO: 105, which may contain one or more amino acid alterations.

[0332] In some embodiments, such antibodies bind to the human LTBP1-proTGFβ1 complex with a KD of <100 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI); and / or such antibodies bind to the human LTBP3-proTGFβ1 complex with a KD of <100 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). In some embodiments, such antibodies bind to the human LTBP1-proTGFβ1 complex with a KD of <50 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI); and / or such antibodies bind to the human LTBP3-proTGFβ1 complex with a KD of <50 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). In some embodiments, such antibodies bind to the human LTBP1-proTGFβ1 complex with a KD of <25 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI); and / or such antibodies bind to the human LTBP3-proTGFβ1 complex with a KD of <25 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). In some embodiments, such antibodies bind to the human LTBP1-proTGFβ1 complex with a KD of <10 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI); and / or such antibodies bind to the human LTBP3-proTGFβ1 complex with a KD of <10 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI).

[0333] In another embodiment, such antibodies are cross-reactive with mouse LTBP1-proTGFβ1. In some embodiments, such antibodies are also cross-reactive with mouse LTBP3-proTGFβ1. In some embodiments, such antibodies bind to mouse LTBP1-proTGFβ1 complexes with a KD of <100 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI); and / or the antibodies bind to mouse LTBP3-proTGFβ1 complexes with a KD of <100 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). In some embodiments, such antibodies bind to mouse LTBP1-proTGFβ1 complexes with a KD of <50 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI); and / or the antibodies bind to mouse LTBP3-proTGFβ1 complexes with a KD of <50 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). In some embodiments, such antibodies bind to mouse LTBP1-proTGFβ1 complexes with a KD of <25 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI); and / or the antibodies bind to mouse LTBP3-proTGFβ1 complexes with a KD of <25 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). In some embodiments, such antibodies bind to mouse LTBP1-proTGFβ1 complexes with a KD of <10 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI); and / or the antibodies bind to mouse LTBP3-proTGFβ1 complexes with a KD of <10 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI).

[0334] In another embodiment, such antibodies do not bind to human GARP-proTGFβ1. In a preferred embodiment, such context-selective antibodies are also isoform-specific, in that they selectively bind to and inhibit activation of TGFβ1 in association with LTBP1 / 3.

[0335] In another aspect, the antibody, or antigen-binding fragment thereof, comprises a CDR-H1 comprising the amino acid sequence G(X1)I(X2)S(X3)SYYW(X4), where X1 can be S or P, X2 can be S, H, or R, X3 can be S or G, and X4 can be G, I, N, or V. In some embodiments, X1 is S. In some embodiments, X1 is P. In some embodiments, X2 is S. In some embodiments, X2 is H. In some embodiments, X2 is R. In some embodiments, X3 is S. In some embodiments, X3 is G. In some embodiments, X4 is G. In some embodiments, X4 is I. In some embodiments, X4 is N. In some embodiments, X4 is V.

[0336] In some embodiments, the antibody, or antigen-binding fragment thereof, comprises a CDR-H2 comprising the amino acid sequence SISYSA(X1)TYYNPSLKS, where X1 can be S or T. In some embodiments, X1 is S. In some embodiments, X1 is T.

[0337] In some embodiments, the antibody, or antigen-binding fragment thereof, has the amino acid sequence (X1)(X2)D(X3)(X4)Y(X5)(X6)(X7)(X8)G(X9)(X 10 )(X 11 X1 may be A or V; X2 may be R, S or G, and X3 may be P, Y, R, V, I, H, T or E; X4 may be S, D, E or N; X5 may be D, A or T; X6 may be S, G, T or A; X7 may be I, A, R, Q, or V; X8 may be A, E, K, G or T; X9 may be M or I; 10 may be D, L, Q, V, N or G; X 11may be V, R, N, E, or K. In some embodiments, X1 is A. In some embodiments, X1 is V. In some embodiments, X2 is R. In some embodiments, X2 is S. In some embodiments, X2 is G. In some embodiments, X3 is P. In some embodiments, X3 is Y. In some embodiments, X3 is R. In some embodiments, X3 is V. In some embodiments, X3 is I. In some embodiments, X3 is H. In some embodiments, X3 is T. In some embodiments, X3 is E. In some embodiments, X4 is S. In some embodiments, X4 is D. In some embodiments, X4 is E. In some embodiments, X4 is N. In some embodiments, X5 is D. In some embodiments, X5 is A. In some embodiments, X5 is T. In some embodiments, X6 is S. In some embodiments, X6 is G. In some embodiments, X6 is T. In some embodiments, X6 is A. In some embodiments, X7 is I. In some embodiments, X7 is A. In some embodiments, X7 is R. In some embodiments, X7 is Q. In some embodiments, X7 is V. In some embodiments, X8 is A. In some embodiments, X8 is E. In some embodiments, X8 is K. In some embodiments, X8 is G. In some embodiments, X8 is T. In some embodiments, X9 is M. In some embodiments, X9 is I. In some embodiments, X 10 is D. In some embodiments, X 10 is L. In some embodiments, X 10 is Q. In some embodiments, X 10 is V. In some embodiments, X 10 is N. In some embodiments, X 10 is G. In some embodiments, X 11 is V. In some embodiments, X 11 is R. In some embodiments, X 11 is N. In some embodiments, X 11 is E. In some embodiments, X 11 is K.

[0338] In some embodiments, the antibody, or antigen-binding fragment thereof, comprises three heavy chain CDRs and three light chain CDRs, wherein the heavy chain CDRs comprise: a) CDR-H1 comprising the amino acid sequence G(X1)I(X2)S(X3)SYYW(X4), wherein X1 can be S or P, X2 can be S, H or R, X3 can be S or G, and X4 can be G, I, N or V; b) CDR-H2 containing the amino acid sequence SISYSA(X1)TYYNPSLKS, where X1 can be S or T; and c) Amino acid sequence (X1) (X2) D (X3) (X4) Y (X5) (X6) (X7) (X8) G (X9) (X 10 )(X 11 X1 may be A or V; X2 may be R, S or G, and X3 may be P, Y, R, V, I, H, T or E; X4 may be S, D, E or N; X5 may be D, A or T; X6 may be S, G, T or A; X7 may be I, A, R, Q, or V; X8 may be A, E, K, G or T; X9 may be M or I; X 10 may be D, L, Q, V, N or G; X 11 may be V, R, N, E or K.

[0339] In some embodiments, the antibody, or antigen-binding fragment thereof, further comprises a CDR-L1 set forth in SEQ ID NO: 103, which may comprise one or more amino acid alterations. In some embodiments, the antibody, or antigen-binding fragment thereof, further comprises a CDR-L2 set forth in SEQ ID NO: 104, which may comprise one or more amino acid alterations. In some embodiments, the antibody, or antigen-binding fragment thereof, further comprises a CDR-L3 set forth in SEQ ID NO: 105, which may comprise one or more amino acid alterations.

[0340] In some embodiments, the antibody, or antigen-binding fragment, comprises at least three of the following six CDRs: a) CDR-H1 comprising the amino acid sequence G(X1)I(X2)S(X3)SYYW(X4), wherein X1 can be S or P, X2 can be S, H or R, X3 can be S or G, and X4 can be G, I, N or V; b) CDR-H2 comprising the amino acid sequence SISYSA(X1)TYYNPSLKS, where X1 may be S or T; c) Amino acid sequence (X1) (X2) D (X3) (X4) Y (X5) (X6) (X7) (X8) G (X9) (X 10 )(X 11 X1 may be A or V; X2 may be R, S or G, and X3 may be P, Y, R, V, I, H, T or E; X4 may be S, D, E or N; X5 may be D, A or T; X6 may be S, G, T or A; X7 may be I, A, R, Q, or V; X8 may be A, E, K, G or T; X9 may be M or I; X 10 may be D, L, Q, V, N or G; X 11 may be V, R, N, E or K; d) CDR-L1: SEQ ID NO: 103, which may contain one or more amino acid alterations; e) CDR-L2: SEQ ID NO: 104, which may contain one or more amino acid alterations; and f) CDR-L3: SEQ ID NO: 105, which may contain one or more amino acid alterations.

[0341] In some embodiments, the antibody, or antigen-binding fragment thereof, specifically binds to the human LTBP1-proTGFβ1 complex and / or the human LTBP3-proTGFβ1 complex, but does not bind to the human GARP-proTGFβ1 complex. In some embodiments, the antibody, or antigen-binding fragment thereof, does not bind to the human GARP-proTGFβ1 complex. In some embodiments, the antibody, or antigen-binding fragment thereof, does not bind to mature TGFβ1, mature TGFβ2, or mature TGFβ3.

[0342] In one particular embodiment, the antibody, or antigen-binding fragment, specifically binds to the human LTBP1-proTGFβ1 complex and / or the human LTBP3-proTGFβ1 complex and does not bind to the human GARP-proTGFβ1 complex; wherein the antibody does not bind to mature TGFβ1, mature TGFβ2, or mature TGFβ3; and wherein the antibody is a fully human or humanized antibody or fragment thereof, and wherein the antibody comprises at least three of the following six CDRs: a) CDR-H1 comprising the amino acid sequence G(X1)I(X2)S(X3)SYYW(X4), wherein X1 can be S or P, X2 can be S, H or R, X3 can be S or G, and X4 can be G, I, N or V; b) CDR-H2 comprising the amino acid sequence SISYSA(X1)TYYNPSLKS, where X1 may be S or T; c) Amino acid sequence (X1) (X2) D (X3) (X4) Y (X5) (X6) (X7) (X8) G (X9) (X 10 )(X 11 X1 may be A or V, X2 may be R, S or G, X3 may be P, Y, R, V, I, H, T or E, X4 may be S, D, E or N, X5 may be D, A or T, X6 may be S, G, T or A, X7 may be I, A, R, Q or V, X8 may be A, E, K, G or T, X9 may be M or I, and X 10may be D, L, Q, V, N or G, and X 11 may be V, R, N, E or K; d) CDR-L1 as set forth in SEQ ID NO: 103, which may contain one or more amino acid alterations; e) CDR-L2 as set forth in SEQ ID NO: 104, which may contain one or more amino acid alterations; and f) CDR-L3 as set forth in SEQ ID NO: 105, which may contain one or more amino acid alterations.

[0343] In some embodiments, such antibodies bind to the human LTBP1-proTGFβ1 complex with a KD of <100 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI); and / or such antibodies bind to the human LTBP3-proTGFβ1 complex with a KD of <100 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). In some embodiments, such antibodies bind to the human LTBP1-proTGFβ1 complex with a KD of <50 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI); and / or such antibodies bind to the human LTBP3-proTGFβ1 complex with a KD of <50 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). In some embodiments, such antibodies bind to the human LTBP1-proTGFβ1 complex with a KD of <25 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI); and / or such antibodies bind to the human LTBP3-proTGFβ1 complex with a KD of <25 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). In some embodiments, such antibodies bind to the human LTBP1-proTGFβ1 complex with a KD of <10 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI); and / or such antibodies bind to the human LTBP3-proTGFβ1 complex with a KD of <10 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI).

[0344] In another embodiment, such antibodies are cross-reactive with mouse LTBP1-proTGFβ1. In some embodiments, such antibodies are also cross-reactive with mouse LTBP3-proTGFβ1. In some embodiments, such antibodies bind to mouse LTBP1-proTGFβ1 complexes with a KD of <100 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI); and / or the antibodies bind to mouse LTBP3-proTGFβ1 complexes with a KD of <100 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). In some embodiments, such antibodies bind to mouse LTBP1-proTGFβ1 complexes with a KD of <50 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI); and / or the antibodies bind to mouse LTBP3-proTGFβ1 complexes with a KD of <50 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). In some embodiments, such antibodies bind to mouse LTBP1-proTGFβ1 complexes with a KD of <25 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI); and / or the antibodies bind to mouse LTBP3-proTGFβ1 complexes with a KD of <25 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). In some embodiments, such antibodies bind to mouse LTBP1-proTGFβ1 complexes with a KD of <10 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI); and / or the antibodies bind to mouse LTBP3-proTGFβ1 complexes with a KD of <10 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI).

[0345] In another embodiment, such antibodies do not bind to human GARP-proTGFβ1. In a preferred embodiment, such context-selective antibodies are also isoform-specific, in that they selectively bind to and inhibit activation of TGFβ1 in association with LTBP1 / 3.

[0346] In another aspect, the antibody, or antigen-binding fragment thereof, comprises a CDR-H1 comprising the amino acids G(X1)I(X2)SSSYYW(X3), where X1 can be S or P; X2 can be H or R; and X3 can be G, I, or N. In some embodiments, X1 is S. In some embodiments, X1 is P. In some embodiments, X2 is H. In some embodiments, X2 is R. In some embodiments, X3 is G. In some embodiments, X3 is I. In some embodiments, X3 is N.

[0347] In some embodiments, the antibody, or antigen-binding fragment thereof, comprises a CDR-H2 comprising the amino acid sequence SISYSA(X1)TYYNPSLKS, where X1 can be S or T. In some embodiments, X1 is S. In some embodiments, X1 is T.

[0348] In some embodiments, the antibody, or antigen-binding fragment thereof, comprises a CDR-H3 comprising the amino acid sequence A(X1)D(X2)SYD(X3)(X4)AGM(X5)(X6), where X1 may be R, S, or G, X2 may be P or V, X3 may be S or A, X4 may be A, R, I, or V, X5 may be D, Q, or G, and X6 may be V or R. In some embodiments, X1 is R. In some embodiments, X1 is S. In some embodiments, X1 is G. In some embodiments, X2 is P. In some embodiments, X2 is V. In some embodiments, X3 is S. In some embodiments, X3 is A. In some embodiments, X4 is A. In some embodiments, X4 is R. In some embodiments, X4 is I. In some embodiments, X4 is V. In some embodiments, X5 is D. In some embodiments, X5 is Q. In some embodiments, X5 is G. In some embodiments, X6 is V. In some embodiments, X6 is R.

[0349] In some embodiments, the antibody, or antigen-binding fragment thereof, comprises three heavy chain CDRs and three light chain CDRs, wherein the heavy chain CDRs comprise: a) CDR-H1 comprising the amino acid sequence G(X1)I(X2)SSSYYW(X3), where X1 can be S or P; X2 can be H or R; and X3 can be G, I, or N; b) CDR-H2 containing the amino acid sequence SISYSA(X1)TYYNPSLKS, where X1 can be S or T; and c) A CDR-H3 comprising the amino acid sequence A(X1)D(X2)SYD(X3)(X4)AGM(X5)(X6), wherein X1 can be R, S, or G, X2 can be P or V, X3 can be S or A, X4 can be A, R, I, or V, X5 can be D, Q, or G, and X6 can be V or R.

[0350] In some embodiments, the antibody, or antigen-binding fragment thereof, further comprises a CDR-L1 set forth in SEQ ID NO: 103, which may comprise one or more amino acid alterations. In some embodiments, the antibody, or antigen-binding fragment thereof, further comprises a CDR-L2 set forth in SEQ ID NO: 104, which may comprise one or more amino acid alterations. In some embodiments, the antibody, or antigen-binding fragment thereof, further comprises a CDR-L3 set forth in SEQ ID NO: 105, which may comprise one or more amino acid alterations.

[0351] In some embodiments, the antibody, or antigen-binding fragment, comprises at least three of the following six CDRs: a) CDR-H1 comprising the amino acid sequence G(X1)I(X2)SSSYYW(X3), where X1 can be S or P; X2 can be H or R; and X3 can be G, I, or N; b) CDR-H2 comprising the amino acid sequence SISYSA(X1)TYYNPSLKS, where X1 may be S or T; c) a CDR-H3 comprising the amino acid sequence A(X1)D(X2)SYD(X3)(X4)AGM(X5)(X6), wherein X1 can be R, S, or G, X2 can be P or V, X3 can be S or A, X4 can be A, R, I, or V, X5 can be D, Q, or G, and X6 can be V or R; d) CDR-L1: SEQ ID NO: 103, which may contain one or more amino acid alterations; e) CDR-L2: SEQ ID NO: 104, which may contain one or more amino acid alterations; and f) CDR-L3: SEQ ID NO: 105, which may contain one or more amino acid alterations.

[0352] In some embodiments, the antibody, or antigen-binding fragment thereof, specifically binds to the human LTBP1-proTGFβ1 complex and / or the human LTBP3-proTGFβ1 complex, but does not bind to the human GARP-proTGFβ1 complex. In some embodiments, the antibody, or antigen-binding fragment thereof, does not bind to the human GARP-proTGFβ1 complex. In some embodiments, the antibody, or antigen-binding fragment thereof, does not bind to mature TGFβ1, mature TGFβ2, or mature TGFβ3.

[0353] In one particular embodiment, the antibody, or antigen-binding fragment thereof, specifically binds to the human LTBP1-proTGFβ1 complex and / or the human LTBP3-proTGFβ1 complex and does not bind to the human GARP-proTGFβ1 complex; wherein the antibody does not bind to mature TGFβ1, mature TGFβ2, or mature TGFβ3; and wherein the antibody is a fully human or humanized antibody or fragment thereof, and wherein the antibody comprises at least three of the following six CDRs: a) CDR-H1 comprising the amino acid sequence G(X1)I(X2)SSSYYW(X3), where X1 can be S or P; X2 can be H or R; and X3 can be G, I, or N; b) CDR-H2 comprising the amino acid sequence SISYSA(X1)TYYNPSLKS, where X1 may be S or T; c) a CDR-H3 comprising the amino acid sequence A(X1)D(X2)SYD(X3)(X4)AGM(X5)(X6), wherein X1 can be R, S, or G, X2 can be P or V, X3 can be S or A, X4 can be A, R, I, or V, X5 can be D, Q, or G, and X6 can be V or R; d) CDR-L1: SEQ ID NO: 103, which may contain one or more amino acid alterations; e) CDR-L2: SEQ ID NO: 104, which may contain one or more amino acid alterations; and f) CDR-L3: SEQ ID NO: 105, which may contain one or more amino acid alterations.

[0354] In some embodiments, such antibodies bind to the human LTBP1-proTGFβ1 complex with a KD of <100 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI); and / or such antibodies bind to the human LTBP3-proTGFβ1 complex with a KD of <100 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). In some embodiments, such antibodies bind to the human LTBP1-proTGFβ1 complex with a KD of <50 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI); and / or such antibodies bind to the human LTBP3-proTGFβ1 complex with a KD of <50 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). In some embodiments, such antibodies bind to the human LTBP1-proTGFβ1 complex with a KD of <25 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI); and / or such antibodies bind to the human LTBP3-proTGFβ1 complex with a KD of <25 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). In some embodiments, such antibodies bind to the human LTBP1-proTGFβ1 complex with a KD of <10 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI); and / or such antibodies bind to the human LTBP3-proTGFβ1 complex with a KD of <10 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI).

[0355] In another embodiment, such antibodies are cross-reactive with mouse LTBP1-proTGFβ1. In some embodiments, such antibodies are also cross-reactive with mouse LTBP3-proTGFβ1. In some embodiments, such antibodies bind to mouse LTBP1-proTGFβ1 complexes with a KD of <100 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI); and / or the antibodies bind to mouse LTBP3-proTGFβ1 complexes with a KD of <100 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). In some embodiments, such antibodies bind to mouse LTBP1-proTGFβ1 complexes with a KD of <50 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI); and / or the antibodies bind to mouse LTBP3-proTGFβ1 complexes with a KD of <50 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). In some embodiments, such antibodies bind to mouse LTBP1-proTGFβ1 complexes with a KD of <25 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI); and / or the antibodies bind to mouse LTBP3-proTGFβ1 complexes with a KD of <25 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI). In some embodiments, such antibodies bind to mouse LTBP1-proTGFβ1 complexes with a KD of <10 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI); and / or the antibodies bind to mouse LTBP3-proTGFβ1 complexes with a KD of <10 nM when measured in a suitable in vitro binding assay, such as biolayer interferometry (BLI).

[0356] In another embodiment, such antibodies do not bind to human GARP-proTGFβ1. In a preferred embodiment, such context-selective antibodies are also isoform-specific, in that they selectively bind to and inhibit activation of TGFβ1 in association with LTBP1 / 3.

[0357] Also provided herein are antibodies, or antigen-binding fragments thereof, that bind to the human LTBP1-proTGFβ1 complex and / or the human LTBP3-TGFβ1 complex with even higher affinity and with an even more advantageous combination of binding properties.

[0358] Thus, in one embodiment, the antibody, or antigen-binding fragment thereof, comprises the following six CDRs: a) CDR-H1 containing the amino acid sequence FTFRSYVMH; b) CDR-H2 containing the amino acid sequence VISHEGS(X1)KYYADSVKG, where X1 is L or G; and c) a CDR-H3 comprising the amino acid sequence A(X1)PRIAARRGGFG(X2), where X1 is V, R, or L and X2 is Y, S, or T; d) CDR-L1 comprising the amino acid sequence TRS(X1)G(X2)ID(X3)NYVQ, where X1 is S or H, X2 is N, L, S or A, and X3 is N, D or Y; e) a CDR-L2 comprising the amino acid sequence ED(X1)(X2)RPS, where X1 is N, F, or A and X2 is Q, I, or V; and f) A CDR-L3 comprising the amino acid sequence Q(X1)YD(X2)(X3)(X4)Q(X5)VV, wherein X1 is S or G, X2 is S, F, Y, D, H or W, X3 is N, D or S, X4 is N, A, L, E or T, and X5 is G, R, A or L.

[0359] In some embodiments, in CDR-H3, X1 is R or L. In CDR-L3, X2 may be Y. In CDR-L3, X3 may be D and X4 may be T. In some preferred embodiments, in CDR-H3, X1 is R or L (or may be R), and in CDR-L3, X2 is Y; in CDR-L3, X3 is D; and X4 is T.

[0360] In an alternative embodiment, in CDR-H3, X1 is R or L (or may be R), in CDR-L3, X2 is Y, and in CDR-L3, X3 is D, X4 is N, and X5 is A.

[0361] In some embodiments, in CDR-L1, X1 is S or H, X2 is N or A, and X3 is N, D, or Y; in CDR-L2, X1 is N or F, and X2 is Q or V; in CDR-L3, X1 is S or G, X2 is S, Y, D, or W, X3 is D or S, X4 is N, L, or T, and X5 is G, R, A, or L. In some embodiments, in CDR-L1, X1 is S, X2 is N, and X3 is N or Y; in CDR-L2, X1 is N, and X2 is Q or V; in CDR-L3, X1 is S or G, X2 is S, Y, or W, X3 is D, X4 is N or T, and X5 is G, R, or A. In some embodiments, in the CDR-L3, X1 is S, X2 is S or Y, X3 is D, X4 is N or T, and X5 is G, R, or A. In some embodiments, in the CDR-L3, X1 is S, X2 is Y, X3 is D, X4 is N or T, and X5 is G or A. In some preferred embodiments, in the CDR-L3, X1 is S, X2 is Y, X3 is D, X4 is T, and X5 is G.

[0362] In particularly preferred embodiments, the antibody or antigen-binding fragment has the CDRs of Ab42, for example: CDR-H1 comprising the amino acid sequence FTFRSYVMH (SEQ ID NO: 166); CDR-H2 comprising the amino acid sequence VISHEGSLKYYADSVKG (SEQ ID NO: 167); CDR-H3 comprising the amino acid sequence ARPRIAARRGGFGY (SEQ ID NO: 168); CDR-L1 comprising the amino acid sequence TRSSGNIDNNYVQ (SEQ ID NO: 169); CDR-L2 comprising the amino acid sequence EDNQRPS (SEQ ID NO: 170); and CDR-L3 comprising the amino acid sequence QSYDYDTQGVV (SEQ ID NO: 171).

[0363] In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain variable region having an amino acid sequence at least 90% identical to SEQ ID NO:318; and a light chain variable region having an amino acid sequence at least 90% identical to SEQ ID NO:319.

[0364] In some embodiments, the antibody or antigen-binding fragment has a K of <5 nM as measured by a suitable in vitro binding assay, such as BLI. D For example, the antibody or antigen-binding fragment binds to the human LTBP1-proTGFβ1 complex and / or the human LTBP3-TGFβ1 complex with a K of <5 nM as measured by a suitable in vitro binding assay, such as BLI. D In some embodiments, the antibody or antigen-binding fragment can bind to the human LTBP1-proTGFβ1 complex and the human LTBP3-TGFβ1 complex with a K of <1 nM as measured by a suitable in vitro binding assay, such as BLI. D It binds to human LTBP1- and / or LTBP3-proTGFβ1 complexes.

[0365] In some embodiments, the antibody, or antigen-binding fragment thereof, does not exhibit detectable binding to the human GARP-proTGFβ1 complex when measured by BLI under the same assay conditions used to measure binding to the human LTBP1-proTGFβ1 complex and / or human LTBP3-TGFβ1. For example, the antibody or antigen-binding fragment may not exhibit detectable binding to the human GARP-proTGFβ1 complex when measured by BLI under the same assay conditions used to measure binding to the human LTBP1-proTGFβ1 complex and human LTBP3-TGFβ1 complex.

[0366] In some embodiments, the antibody, or antigen-binding fragment thereof, has a K D at least 50-fold lower (e.g., at least 75-fold lower, at least 100-fold lower) than D For example, the antibody, or antigen-binding fragment thereof, binds to the human LTBP1-proTGFβ1 complex and / or the human LTBP3-TGFβ1 complex under the same assay conditions with a K D at least 50-fold lower (e.g., at least 75-fold lower, at least 100-fold lower) than D In some embodiments, the K D is determined by BLI or SPR. D is determined by SPR.

[0367] In some embodiments, the antibody, or antigen-binding fragment thereof, does not exhibit detectable binding to the LRRC33-proTGFβ1 latent complex when measured by BLI under the same assay conditions used to measure binding to the human LTBP1-proTGFβ1 complex and / or human LTBP3-TGFβ1. For example, the antibody, or antigen-binding fragment thereof, may not exhibit detectable binding to the LRRC33-proTGFβ1 latent complex when measured by BLI under the same assay conditions used to measure binding to the human LTBP1-proTGFβ1 complex and human LTBP3-TGFβ1.

[0368] In some embodiments, the antibody, or antigen-binding fragment thereof, has a K D at least 50-fold lower (e.g., at least 75-fold lowe...

Claims

1. An isolated antibody that specifically binds to a human LTBP1-proTGFβ complex and / or a human LTBP3-proTGFβ complex, but does not bind to a human GARP-proTGFβ complex, the antibody does not bind to mature TGFβ1, mature TGFβ2, or mature TGFβ3; the antibody is a fully human or humanized antibody, or an antigen-binding fragment thereof; The antibody has the following six CDRs: a) CDR-H1: SEQ ID NO: 94: i. the threonine residue at position 2 of SEQ ID NO:94 may be substituted with alanine; ii. the asparagine residue at position 4 of SEQ ID NO: 94 may be substituted with alanine, tyrosine, aspartic acid, serine, arginine, or histidine; iii. The asparagine residue at position 5 of SEQ ID NO: 94 may be substituted with glutamine, serine, glycine, lysine, glutamic acid, arginine, or histidine; iv. the tyrosine residue at position 6 of SEQ ID NO: 94 may be substituted with arginine; v. The proline residue at position 7 of SEQ ID NO:94 may be substituted with glycine, alanine, leucine, serine, asparagine, valine, aspartic acid, or glutamine; vi. the isoleucine residue at position 8 of SEQ ID NO: 94 may be substituted with methionine or leucine; and / or vii. The histidine residue at position 9 of SEQ ID NO: 94 may be substituted with phenylalanine, tyrosine, asparagine, or serine; b) CDR-H2: SEQ ID NO: 95, containing up to six amino acid changes; c) CDR-H3: SEQ ID NO: 96, containing up to three amino acid changes; d) CDR-L1: SEQ ID NO: 97, containing up to three amino acid changes; e) CDR-L2: SEQ ID NO: 98, containing up to three amino acid changes; and f) CDR-L3: SEQ ID NO: 99, containing up to three amino acid changes at least three of antibody.

2. An isolated antibody that specifically binds to a human LTBP1-proTGFβ complex and / or a human LTBP3-proTGFβ complex, but does not bind to a human GARP-proTGFβ complex, the antibody does not bind to mature TGFβ1, mature TGFβ2, or mature TGFβ3; the antibody is a fully human or humanized antibody, or an antigen-binding fragment thereof; the antibody comprises a heavy chain variable region having an amino acid sequence at least 90% identical to SEQ ID NO: 88; and / or the antibody comprises a variable light chain variable region having an amino acid sequence at least 90% identical to SEQ ID NO: 89; antibody.

3. The following six CDRs: a) Amino acid sequence FTF(X １ ) (X ２ ) CDR-H1 containing YVMH, wherein X １ is S or R, and X ２ is G or S; b) Amino acid sequence (X １ ) ISHEG (X ２ ) (X ３ ) CDR-H2 containing KYYADSVKG, wherein X １ is V or S, and X ２ is S or G, and X ３ is F or L; and c) amino acid sequence (X １ ) (X ２ ) P(X ３ ) (X ４ ) (X ５ ) (X ６ ) RRGG (X ７ ) (X ８ ) (X ９ and a CDR-H3 comprising: １ is A or V, and X ２ is R, V, G or K, and X ３ is R, H or L, and X ４ is I, V or G, and X ５ is A, S, or L, and X ６ is A or V, and X ７ is F or Y, and X ８ is D, G, R, or S, and X ９ is Y, G, R, L, V, A or K d) CDR-L1 as set forth in SEQ ID NO: 97, containing up to three amino acid changes; e) CDR-L2 as set forth in SEQ ID NO: 98, containing up to three amino acid changes; and f) CDR-L3 as set forth in SEQ ID NO: 99, containing up to three amino acid changes at least three of An antibody, or an antigen-binding fragment thereof.

4. 4. The antibody, or antigen-binding fragment thereof, of claim 3, b) in CDR-H2, X ２ is S; and c) in CDR-H3, X １ is A and X ２ is R or V, and X ３ is R and X ４ is I and X ５ is A or L, and X ６ is A and X ７ is F and X ８ is G and X ９ is Y, An antibody, or an antigen-binding fragment thereof.

5. The antibody of any one of claims 1 to 4, the antibody comprises a heavy chain variable region having an amino acid sequence at least 90% identical to SEQ ID NO: 88; and comprising a light chain variable region having an amino acid sequence at least 90% identical to SEQ ID NO: 89; antibody.

6. 6. The antibody, or antigen-binding fragment thereof, of any one of claims 3 to 5, The up to three amino acid changes include up to two amino acid changes. An antibody, or an antigen-binding fragment thereof.

7. 10. The antibody, or antigen-binding fragment thereof, of any one of the preceding claims, comprising: containing all six CDRs, An antibody, or an antigen-binding fragment thereof.

8. 10. The antibody of any one of the preceding claims, The antibody is specific to the human LTBP1-TGFβ1 complex. antibody.

9. 10. The antibody of any one of the preceding claims, The antibody is specific to the human LTBP3-TGFβ1 complex. antibody.

10. 10. The antibody of any one of the preceding claims, The antibody is specific to human LTBP1-TGFβ1 complex and human LTBP3-TGFβ1 complex. antibody.

11. The following six CDRs: a) CDR-H1 comprising the amino acid sequence FTFRSYVMH; b) the amino acid sequence VISHEGS(X １ ) CDR-H2 containing KYYADSVKG, wherein X １ is L or G; and c) amino acid sequence A(X １ )PRIAARRGGGFG(X ２ and a CDR-H3 comprising: １ is V, R or L, and X ２ is Y, S or T; d) the amino acid sequence TRS(X １ ) G (X ２ ) ID(X ３ ) CDR-L1 comprising NYVQ, wherein X １ is S or H, and X ２ is N, L, S or A, and X ３ is N, D or Y; e) the amino acid sequence ED(X １ ) (X ２ ) a CDR-L2 comprising an RPS, wherein X １ is N, F or A, and X ２ is Q, I, or V; and f) amino acid sequence Q(X １ ) YD(X ２ ) (X ３ ) (X ４ ) Q(X ５ ) a CDR-L3 comprising VV, wherein X １ is S or G, and X ２ is S, F, Y, D, H or W, and X ３ is N, D or S, and X ４ is N, A, L, E or T, and X ５ is G, R, A or L Including, An antibody, or an antigen-binding fragment thereof.

12. 12. The antibody, or antigen-binding fragment thereof, of claim 11, In CDR-H3, X １ is R or L; An antibody, or an antigen-binding fragment thereof.

13. 13. The antibody, or antigen-binding fragment thereof, of claim 12, In CDR-L3, X ２ is Y, An antibody, or an antigen-binding fragment thereof.

14. 14. The antibody, or antigen-binding fragment thereof, of claim 13, In CDR-L3, X ３ is D and X ４ is T, An antibody, or an antigen-binding fragment thereof.

15. 14. The antibody, or antigen-binding fragment thereof, of claim 13, In CDR-L3, X ３ is D and X ４ is N and X ５ is A, An antibody, or an antigen-binding fragment thereof.

16. 13. The antibody, or antigen-binding fragment thereof, of claim 12, In CDR-L1, X １ is S or H, and X ２ is N or A, and X ３ is N, D or Y; In CDR-L2, X １ is N or F, and X ２ is Q or V; and In CDR-L3, X １ is S or G, and X ２ is S, Y, D or W, and X ３ is D or S, and X ４ is N, L or T, and X ５ is G, R, A or L; An antibody, or an antigen-binding fragment thereof.

17. 17. The antibody, or antigen-binding fragment thereof, of claim 16, In CDR-L1, X １ is S and X ２ is N and X ３ is N or Y; In CDR-L2, X １ is N and X ２ is Q or V; and In CDR-L3, X １ is S or G, and X ２ is S, Y or W, and X ３ is D and X ４ is N or T, and X ５ is G, R or A; An antibody, or an antigen-binding fragment thereof.

18. 18. The antibody, or antigen-binding fragment thereof, of claim 17, In CDR-L3, X １ is S and X ２ is S or Y, and X ３ is D and X ４ is N or T, and X ５ is G, R or A; An antibody, or an antigen-binding fragment thereof.

19. 19. The antibody, or antigen-binding fragment thereof, of claim 18, In CDR-L3, X １ is S and X ２ is Y and X ３ is D and X ４ is N or T, and X ５ is G or A; An antibody, or an antigen-binding fragment thereof.

20. 20. The antibody, or antigen-binding fragment thereof, of claim 19, In CDR-L3, X １ is S and X ２ is Y and X ３ is D and X ４ is T and X ５ is G, An antibody, or an antigen-binding fragment thereof.

21. 21. The antibody, or antigen-binding fragment thereof, of any one of claims 16 to 20, a) CDR-H1 comprises the amino acid sequence of SEQ ID NO: 166; b) CDR-H2 comprises the amino acid sequence of SEQ ID NO: 167; c) CDR-H3 comprises the amino acid sequence of SEQ ID NO: 168; d) CDR-L1 comprises the amino acid sequence of SEQ ID NO: 169; e) CDR-L2 comprises the amino acid sequence of SEQ ID NO: 170; and f) CDR-L3 comprises the amino acid sequence of SEQ ID NO: 171; An antibody, or an antigen-binding fragment thereof.

22. 22. The antibody, or antigen-binding fragment thereof, of any one of claims 11 to 21, a heavy chain variable region having an amino acid sequence at least 90% identical to SEQ ID NO: 318; and comprising a light chain variable region having an amino acid sequence at least 90% identical to SEQ ID NO: 319, An antibody, or an antigen-binding fragment thereof.

23. 23. The antibody, or antigen-binding fragment thereof, of any one of claims 11 to 22, competes or cross-competes with an antibody having a heavy chain variable region sequence set forth in SEQ ID NO: 318 and a light chain variable region sequence set forth in SEQ ID NO: 319; An antibody, or an antigen-binding fragment thereof.

24. selectively binds to the human LTBP1-TGFβ1 complex and the human LTBP3-TGFβ1 complex, and competes or cross-competes with an antibody having a heavy chain variable region sequence shown in SEQ ID NO: 318 and a light chain variable region sequence shown in SEQ ID NO: 319; An antibody, or an antigen-binding fragment thereof.

25. 25. The antibody, or antigen-binding fragment thereof, of any one of claims 11 to 24, does not exhibit detectable binding to human GARP-proTGFβ1 complexes when measured by BLI under the same assay conditions used to measure binding to human LTBP1-proTGFβ1 complexes and human LTBP3-TGFβ1 complexes; An antibody, or an antigen-binding fragment thereof.

26. 26. The antibody, or antigen-binding fragment thereof, of any one of claims 11 to 25, K for binding to human GARP-proTGFβ1 complex under identical assay conditions Ｄ At least 50 times lower than Ｄ binds to human LTBP1-proTGFβ1 complex and / or human LTBP3-TGFβ1 complex at An antibody, or an antigen-binding fragment thereof.

27. 27. The antibody, or antigen-binding fragment thereof, of any one of claims 11 to 26, does not exhibit detectable binding to the LRRC33-proTGFβ1 complex when measured by BLI under the same assay conditions used to measure binding to human LTBP1-proTGFβ1 complex and human LTBP3-TGFβ1 complex; An antibody, or an antigen-binding fragment thereof.

28. 28. The antibody, or antigen-binding fragment thereof, of any one of claims 11 to 27, The antibody, or antigen-binding fragment thereof, has a monovalent binding half-time (t) of at least 45 minutes for each of the hLTBP1-proTGFβ1 and hLTBP3-proTGFβ1 complexes, as measured by SPR. １／２ ) An antibody, or an antigen-binding fragment thereof.

29. 29. The antibody, or antigen-binding fragment thereof, of claim 28, Monovalent t times of less than 5 minutes for each of the hGARP-proTGFβ1 and hLRRC33-proTGFβ1 complexes as measured by SPR. １／２ having An antibody, or an antigen-binding fragment thereof.

30. 10. The antibody, or antigen-binding fragment thereof, of any one of the preceding claims, comprising: K<5 nM as measured by biolayer interferometry (BLI) Ｄ binds to human LTBP1-proTGFβ1 complex and human LTBP3-TGFβ1 complex at <1 nM, which may be <1 nM; An antibody, or an antigen-binding fragment thereof.

31. 10. The antibody, or antigen-binding fragment thereof, of any one of the preceding claims, comprising: Cross-reactive with mouse LTBP1-proTGFβ1 An antibody, or an antigen-binding fragment thereof.

32. 10. The antibody, or antigen-binding fragment thereof, of any one of the preceding claims, comprising: Cross-reactive with mouse LTBP3-proTGFβ1 An antibody, or an antigen-binding fragment thereof.

33. 10. The antibody, or antigen-binding fragment thereof, of any one of the preceding claims, comprising: K<10 nM as measured by biolayer interferometry (BLI) Ｄ binds to the mouse LTBP1-proTGFβ1 complex at An antibody, or an antigen-binding fragment thereof.

34. 10. The antibody, or antigen-binding fragment thereof, of any one of the preceding claims, comprising: K<10 nM as measured by biolayer interferometry (BLI) Ｄ binds to the mouse LTBP3-proTGFβ1 complex at An antibody, or an antigen-binding fragment thereof.

35. 10. The antibody, or antigen-binding fragment thereof, of any one of the preceding claims, comprising: cross-reacts with human and murine LTBP1-proTGFβ1 and LTBP3-proTGFβ1 complexes, respectively, with a KD of <5 nM, or which may be <1 nM; An antibody, or an antigen-binding fragment thereof.

36. 10. The antibody, or antigen-binding fragment thereof, of any one of the preceding claims, comprising: the antibody is of the IgG4 or IgG1 subtype, wherein the antibody may be of the human IgG4 subtype and may contain a Ser to Pro backbone substitution resulting in an IgG1-like hinge; An antibody, or an antigen-binding fragment thereof.

37. 10. A method for producing a composition comprising the antibody of any one of the preceding claims and a pharmaceutically acceptable excipient. Pharmaceutical compositions.

38. 38. The pharmaceutical composition of claim 37, Prepared for intravenous or subcutaneous administration, Pharmaceutical compositions.

39. a multi-dose vial containing the pharmaceutical composition of claim 37 or 38. composition.

40. 39. A composition comprising a single dose syringe containing the pharmaceutical composition of claim 37 or 38, The syringe may be a disposable syringe. composition.

41. 41. A composition according to any one of claims 37 to 40 for use in a method for the treatment of a fibrotic condition in a human subject, comprising: The treatment comprises administering to the subject the composition in an amount effective to treat the fibrotic disorder. composition.

42. 42. A composition for use according to claim 41, comprising: the fibrotic disorder is organ fibrosis; composition.

43. 43. A composition for use according to claim 42, comprising: The organ fibrosis is progressive organ fibrosis. composition.

44. 44. A composition for use according to claim 42 or 43, comprising: The organ fibrosis is selected from the group consisting of renal fibrosis, liver fibrosis, pulmonary fibrosis, cardiac fibrosis, pancreatic fibrosis, skin fibrosis, scleroderma, muscle fibrosis, uterine fibrosis and endometriosis; composition.

45. 45. A composition for use according to claim 44, comprising: The pulmonary fibrosis is idiopathic pulmonary fibrosis (IPF); composition.

46. 45. A composition for use according to claim 44, comprising: The subject has chronic kidney disease (CKD). composition.

47. 45. A composition for use according to claim 44, comprising: The liver fibrosis is associated with nonalcoholic steatohepatitis (NASH); composition.

48. 48. A composition for use according to any one of claims 41 to 47, comprising: the antibody is administered to the subject at a dosage of 0.1 to 30 mg / kg; composition.

49. 49. A composition for use according to claim 48, comprising: the antibody is administered twice a week, once a week, once every two weeks, once every three weeks, once a month, or every other month; composition.

50. 49. A composition for use according to claim 48, comprising: The therapeutic regimen comprises an initial phase of treatment and a subsequent phase of treatment, wherein the subject receives a loading dose during the initial phase, followed by a maintenance dose during the subsequent phase. composition.

51. 51. A composition for use according to claim 50, comprising: The loading dose is 2 to 30 mg / kg, and the maintenance dose is 0.1 to 20 mg / kg. composition.

52. 52. A composition for use according to claim 50 or 51, comprising: The loading dose is administered to the subject twice a week or once a week. composition.

53. 53. A composition for use according to any one of claims 50 to 52, comprising: the maintenance dose is administered to the subject once every 2 to 8 weeks; composition.

54. 54. A composition for use according to any one of claims 41 to 53, comprising: The method further comprises testing or confirming expression of TGFβ1, LTBP1 or LTBP3 in a biological sample collected from the subject. composition.

55. 41. A method for producing the composition of any one of claims 37 to 40, comprising an antibody, or an antigen-binding fragment thereof, that specifically binds to human LTBP1-proTGFβ complex and / or human LTBP3-proTGFβ complex, comprising: The method comprises: i) a t of at least 45 minutes １／２ selecting an antibody or antigen-binding fragment thereof that dissociates from the human LTBP1-proTGFβ complex and / or the human LTBP3-proTGFβ complex; and ii) formulating said antibody or fragment into a pharmaceutical composition, thereby producing a composition comprising said antibody or fragment; Including, method.

56. 56. The method of claim 55, IC of <5 nM as measured by cell-based assay ５０ and selecting an antibody or antigen-binding fragment having a mAb of 0.1 nM, which may be <2 nM. method.

57. 57. The method of claim 55 or 56, further comprising confirming efficacy in an in vivo preclinical model; wherein the preclinical model may be a liver fibrosis model, a kidney fibrosis model, or a cardiac fibrosis model; method.

58. 58. The method of any one of claims 55 to 57, The method further comprises selecting an antibody or fragment that is cross-reactive to human and rodent antigens. method.

59. 59. The method of any one of claims 55 to 58, The method further comprises subjecting the antibodies or fragments present in the first pool of antibodies and the second pool of antibodies to affinity maturation and / or optimization, thereby providing affinity matured and / or optimized antibodies or fragments. method.

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