WO2019183476A1 - Sustained-release biopolymer-immunotoxin conjugates and methods of using same - Google Patents

Abstract

Described herein are biopolymer-immunotoxin polypeptide conjugates for the sustained- release delivery of immunotoxins. Also described herein are methods of using the compositions.

Description

SUSTAINED-RELEASE BIOPOLYMER-IMMUNOTOXIN CONJUGATES AND

METHODS OF USING SAME

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] T his application claims priority to U.S. Provisional Application No. 62/647,199, filed March 23, 2018, which is hereby incorporated by reference m its entirety.

SEQUENCE LISTING

[0002] The sequence listing is filed with the application in electronic format only and is incorporated by reference herein. The sequence listing text file "028193-9321 -

WO01 As _Filed Sequence List.txt" was created on March 19, 2019, and is 4,365 bytes in size.

TECHNICAL FIELD

[0003] The present disclosure relates to novel biopolymer-immunotoxin conjugates for the sustained-release deliver} of protein drugs.

STATEMENT REGARDING FEDERALLY-SPONSORED RESEARCH OR

DEVELOPMENT

[0004] This invention was made with Government support under Federal Grant Nos.

3332362 and 2032363 awarded by the NSF and NIH, respectively. The Federal Government has certain rights to this invention.

BACKGROUND OF THE INVENTION

[0005] Gliobl astoma multiforme (GBM) is the most common and malignant primary brain tumor despite extensive treatment measures and intense research efforts. The aggressive and complex nature of GBM growth typically results in a poor survival prognosis of less than a year. Treatment with an immunotoxin has been shown to improve survival >300% in a GBM mouse model. However, a critical barrier to use of these highly effective biologic drugs is their high solubility and therefore rapid clearance, resulting m eventual tumor recurrence and limitation of the clinical relevance of these compounds. The current solution for extended drug administration is the use of a catheter pump inserted into the brain for hours to days. This method is

burdensome for patients and can result in inconsistent administration or catheter leakage.

[0006] Thus, there is an urgent need for innovative therapies that surpass the often debilitating and ineffectual clinical standard of care. BRIEF SUMMARY OF THE INVENTION

[0007] In one aspect, the disclosure provides biopolymer-immunotoxin polypeptide conjugates comprising at least one targeting domain, a thermally responsive biopolymer, and a bacterial toxin.

[0008] In another aspect, the disclosure provides pharmaceutical compositions comprising the biopolymer-immunotoxin polypeptide conjugates disclosed herein.

[0009] In another aspect, the disclosure provides a method of treating cancer comprising administering to a subject in need thereof a therapeutically effective amount of the biopolymer- immunotoxin polypeptide conjugates disclosed herein or the pharmaceutical compositions disclosed herein.

[0010] Other aspects and embodiments of the disclosure will become apparent in light of the following description and drawings.

BRIEF DESCRIPTIONS OF THE DRAWINGS

[0011] FIG. 1 is a schematic of an AffETx library'. In some embodiments, one, two, or four Affibody domains are fused to an ELP, followed by a flexible linker, and the toxin on the C~ terminus. For some embodiments, the toxin comprises LO10R. For LOIOR, the C -terminal region of the toxin is required for its activity'.

[0012] FIG. 2 is an SDS-PAGE showing purity' of exemplary' AffETx constructs and controls after refolding.

[0013] FIG. 3A, FIG. 3B, FIG. 3C, and FIG. 3D are graphs showing ceil viability assay dose response curves of AffETx in transfected murine 3T3 fibroblast lines. Fibroblasts were stably transfected to express human EGFR (FIG. 3 A) or human EGFRvIII (FIG 3B) form of human EGFR. Control fibroblasts expressed neither form of human EGFR (FIG. 3C). A summary of the ECso values for the AffETx library is provided in FIG. 3D

[0014] FIG. 4A and FIG. 4B are graphs showing cell viability and potency of AffETx in established human patient- derived GBM cell lines D270MG (FIG. 4A) and A172 (FIG. 4B).

[0015] FIG. 5A and FIG. 5B are flow cytometry results with Alexa488-labeled (ZEGFR)₂- ELPA incubated with EGFR-transfected fibroblasts (FIG. 5 A) or explanted xenograft D27QMG GBM cells (FIG. 5B) in accordance with one embodiment of the present disclosure. [0016] FIG. 6 is a line graph showing the change in optical density of each construct followed at 350nm at a range of concentrations and temperatures from 15 to 40 °C. The Tt was derived as the mid-point of the transition curves. The Tt corresponding to each concentration of the AffETx constructs was used to construct the semi-log plot that describes the relationship between ELP fusion protein concentration and T_t.

[0017] FIG. 7A and FIG. 7B are graphs showing the potency of AffETx in two murine GBM lines. AffETx exhibits picomolar efficacy m CT-2A (FIG. 7 A) and SMA560 (FIG. 7B).

[0018] FIG. 8A and FIG. 8B are graphs showing AffETx efficacy in CT-2A orthotopic model. Cumulative survival of mice (FIG. 8A) reveals four treatment groups with significantly improved survival as compared to vehicle control, with (**) indicating p < .01 and (*) indicating p < .05 (Mantel-Cox log rank test). FIG. 8B shows body weight change as a percentage of starting body weight. Arrow indi cates day of AffETx treatment.

[0019] FIG. 9A and FIG. 9B are graphs showing AffETx efficacy in CT-2A orthotopic model. Cumulative survival of mice (FIG. 9A) reveals one treatment group with significantly improved survival as compared to vehicle control, with (**) indicating p < .01 (Mantel-Cox log rank test). FIG. 9B show¾ body weight change as a percentage of starting body weight. Arrow indicates day of treatment.

DETAILED DESCRIPTION OF THE INVENTION

[0020] Disclosed herein are biopolymer-immunotoxin polypeptide conjugates comprising at least one targeting domain, a thermally responsive biopolymer, and a bacterial toxin and their methods of use. The biopolymer-immunotoxin polypeptide conjugates are able to overcome the intrinsic limitations of protein-based drugs by utilizing a thermally responsive biopolymer. The thermally responsive biopolymer-driven depot may sustain levels of a protein-based drug in the tumor for days longer than continuous infusion with a single, non-invasive injection. Further, the depot showed slow, consistent diffusion into the surrounding tissue for zero order release, rather than the first order burst-and-decay of convection enhanced delivery which results in inconsistent tumor coverage.

[0021] The depot further benefits from the advantages of immunotoxin treatment. Bacterial toxins have the capability of killing cells at picomolar concentrations regardless of cell cycle status, in a manner orthogonal to small molecule chemotherapeutics by inhibiting protein translation. Unregulated protein translation has been implicated as a driver of GBM progression; similarly, the proposed tumor cell targets have been proven to promote tumorigenesis through their expression on tumor initiating cells. Given that biopolymer-immunotoxm conjugates described herein directly address two salient drivers of disease progression, the conjugates may provide a potential treatment to eliminate current disease and prevent future tumorigenesis at the pharmacokinetic and molecular level. As such, the compositions described herein have the potential to alter current clinical standard practices for GBM by introducing the possibility of sustained-release biologic drugs. Further, a biologic depot of the compositions described herein may be extended for drug delivery in other solid tumors.

1. Definitions

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the present document, including definitions, will control. Preferred methods and materials are described below, although methods and materials similar or equivalent to those described herein may be used in practice or testing of the present invention. All publications, patent applications, patents and other references mentioned herein are incorporated by reference in their entirety. The materials, methods, and examples disclosed herein are illustrative only and not intended to be limiting.

[0023] The terms“comprise(s),”“include(s),”“having,” ‘has,”“can,” “contain(s),” and variants thereof, as used herein, are intended to be open-ended transitional phrases, terms, or words that do not preclude the possibility of additional acts or structures. The singular forms“a,” “an” and“the” include plural references unless the context clearly dictates otherwise. The present disclosure also contemplates other embodiments“comprising,”“consisting of” and

‘consisting essentially of,” the embodiments or elements presented herein, whether explicitly set forth or not.

[0024] The modifier“about” used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (for example, it includes at least the degree of error associated with the measurement of the particular quantity). The modifier“about” should also be considered as disclosing the range defined by the absolute values of the two endpoints. For example, the expression“from about 2 to about 4” also discloses the range“from 2 to 4.” The term“about” may refer to plus or minus 10% of the indicated number. For example,“about 10%” may indicate a range of 9% to 1 1%, and“about 1” may mean from 0.9-1.1. Other meanings of“about” may be apparent from the context, such as rounding off, so, for example “about 1” may also mean from 0.5 to 1.4.

[0025] For the recitation of numeric ranges herein, each intervening number there between with the same degree of precision is explicitly contemplated. For example, for the range of 6-9, the numbers 7 and 8 are contemplated in addition to 6 and 9, and for the range 6.0-7.0, the number 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, and 7.0 are explicitly contemplated.

[0026] As used herein, the terms“administering,”“providing” and“introducing” are used interchangeably and refer to the placement of the compositions of the disclosure into a subject by a method or route that results in at least partial localization of the composition to a desired site. The compositions may be administered by any appropriate route that results in delivery to a desired location in the subject.

[0027] As used herein, the term“AffETx” refers to a recombinant fusion protein with three functional components: an Affibody protein for targeting, an elastin-like polypeptide (ELP) biopolymer for depot formation, and a cytotoxic bacterial toxin.

[0028] As used herein, the term“Affibody” refers to the Affibody protein used for targeting. Affibody domains are triple helical scaffold proteins derived from the IgG-bmdmg domain of Staphyloccocus aureus protein A and engineered to bind specific, unique targets with high (pi co- nanomolar) affinity. In some embodiments, the Affibody targets the human epidermal growth factor receptor (EGFR) and comprises ZEGFR: 1907, SEQ ID NO: 1.

[0029] As used herein, the term“amino acid” refers to naturally occurring and non-natural synthetic ammo acids, as well as amino acid analogs and amino acid mimetics that function in a manner similar to the naturally occurring amino acids. Naturally occurring amino acids are those encoded by the genetic code. Amino acids can be referred to herein by either their commonly known three-letter symbols or by the one-letter symbols recommended by the IUPAC-IUB Biochemical Nomenclature Commission. Amino acids include the side chain and polypeptide backbone portions.

[0030] As used herein, the term“chemotherapeutic” or“anti-cancer drug” includes any drug used in cancer treatment or any radiation sensitizing agent. Chemotherapeutics may include alkylating agents (including, but not limited to, cyclophosphamide, mechlorethamine,

3 chlorambucil, melphalan, dacarbazine, nitrosoureas, and temozoiomide), anthracyclines

(including, but not limited to, daunorubicin, doxorubicin, epirubicin, idarubicin, mitoxantrone, and valrubicin), cytoskeletal disrupters or taxanes (including, but not limited to, paclitaxel, docetaxel, abraxane, and taxotere), epothilones, histone deacetyiase inhibitors (including, but not limited to, vonnostat and romidepsin), topoisomerase inhibitors (including, but not limited to, irinotecan, topotecan, etoposide, tenoposide, and tafluposide), kinase inhibitors (including, but not limited to, bortezomib, erlotmib, gefitinib, imantinib, vemurafenib, and vismodegib), nucleotide analogs and precursor analogs (including, but not limited to, azacitidine, azatinoprine, capecitabine, cytarabine, doxiflundine, fluorouracil, gemcitabme, hydroxyurea, mercaptopurme, methotrexate, and tioguanine), peptide antibiotics (including, but not limited to, bleomycin and actinomycin), platinum-based agents (including, but not limited to, carboplatin, cispiatin and oxaliplatin), retinoids (including, but not limited to, tretinoin, alitretinoin, and bexarotene), vinca alkaloids and derivatives (including, but not limited to, vinblastine, vincristine, vindesine, and vinorelhine), or combinations thereof The chemotherapeutic may in any form necessary for efficacious administration and functionality'.

[0031] As used herein, the terms“depot” or“intratumoral depot” refers to the location of administration.

As used herein, the terms“effective amount” or“therapeutically effective amount,” refer to a sufficient amount of an agent or a composition or combination of compositions being administered which will relieve to some extent one or more of the symptoms of the disease or condition being treated. The result can be reduction and/or alleviation of the signs, symptoms, or causes of a disease, or any other desired alteration of a biological system. For example, an "effective amount" for therapeutic uses is the amount of the composition comprising a composition as disclosed herein that may provide a clinically significant decrease in disease symptoms. An appropriate "effective" amount in any individual case may be determined using techniques, such as a dose escalation study. The dose could be administered in one or more administrations. However, the precise determination of what would be considered an effective dose may be based on factors individual to each patient, including, but not limited to, the patient's age, size, type or extent of disease, stage of the disease, route of administration of the regenerative cells, the type or extent of supplemental therapy used, ongoing disease process and type of treatment desired (e.g., aggressive vs. conventional treatment). |Ό033] As used herein, the term“EGFRvIII” refers to the human EGFR deletion variant found exclusively in Glioblastoma multiforme.

[0034] A“peptide” or“polypeptide” is a linked sequence of two or more amino acids linked by peptide bonds. The polypeptide may be natural, synthetic, or a modification or combination of natural and synthetic. Domains are portions of a polypeptide or protein that form a compact unit and are typically 15 to 350 amino acids long.

[0035] As used herein, the term "preventing" refers to partially or completely delaying onset of an infection, disease, disorder and/or condition; partially or completely delaying onset of one or more symptoms, features, or clinical manifestations of a particular infection, disease, disorder, and/or condition; partially or completely delaying onset of one or more symptoms, features, or manifestations of a particular infection, disease, disorder, and/or condition; partially or completely delaying progression from an infection, a particular disease, disorder and/or condition; and/or decreasing the risk of developing pathology associated with the infection, the disease, disorder, and/or condition.

[0036] A“subject” or“patient” may be human or non-human and may include, for example, animal strains or species used as“model systems” for research purposes, such a mouse model as described herein. Likewise, patient may include either adults or juveniles (e.g., children).

Moreover, patient may mean any living organism, preferably a mammal (e.g, human or non human) that may benefit from the administration of compositions contemplated herein. Examples of mammals include, but are not limited to, any member of the Mammalian class: humans, non human primates such as chimpanzees, and other apes and monkey species; farm animals such as cattle, horses, sheep, goats, swine; domestic animals such as rabbits, dogs, and cats; laboratory animals including rodents, such as rats, mice and guinea pigs, and the like. Examples of non- mammals include, but are not limited to, birds, fish and the like. In one embodiment of the methods and compositions provided herein, the mammal is a human.

[0037] As used herein, the term“sustained-release” describes the release profile of AffETx from the intratumoral depot. While drugs administered intravenously as a bolus are rapidly cleared from circulation with second-order pharmacokinetics, use of the biopolymer- immunotoxin conj ugates described herein stabilizes an intratumoral depot will allow for near zero-order drug release over several days and therefore more effective tumor clearance. [0038] As used herein, the term“transition temperature” or“Tt” refers to the temperature at which the material changes from one state to another, for example, soluble to insoluble. For example, below^r the Tt the conjugate may be highly soluble. Upon heating above the transition temperature, for example, the conjugate may aggregate, forming a separate phase.

[0039] As used herein, "treat," "treating" and the like mean a slowing, stopping or reversing of progression of a disease or disorder when provided a composition described herein to an appropriate control subject. The terms also mean a reversing of the progression of such a disease or disorder to a point of eliminating or greatly reducing the cell proliferation. As such, "treating" means an application or administration of the compositions described herein to a subject, where the subject has a disease or a symptom of a disease, where the purpose is to cure, heal, alleviate, relieve, alter, remedy, ameliorate, improve or affect the disease or symptoms of the disease. As used herein, "treatment,”“therapy” and/or“therapy regimen” refer to the clinical intervention made in response to a disease, disorder or physiological condition manifested by a patient or to which a patient may be susceptible. The aim of treatment includes the alleviation or prevention of symptoms, slowing or stopping the progression or worsening of a disease, disorder, or condition and/or the remission of the disease, disorder or condition.

[004Q] Provided herein are biopolymer-immunotoxin polypeptide conjugates comprising at least one targeting domain, a thermally responsive biopolymer, and a bacterial toxin

a) Targeting Domain

[0041] The biopolymer-immunotoxin polypeptide conjugate may include at least one targeting domain. In some embodiments, the conjugate may include at least one, at least two, at least three, at least four, at least five, at least six, at least seven, at least eight, at least nine, or at least ten targeting domains. In some embodiments, the conjugate may include less than two, less than three, less than four, less than five, less than six, less than seven, less than eight, less than nine, or less than ten targeting domains.

[0042] The at least one targeting domain may be configured to bind a target of interest. The target of interest may include cell surface proteins, cell surface carbohydrate moieties, or cellular receptors that are upregulated in certain cancer types. In some embodiments, the at least one targeting domain is configured to bind to the epidermal growth factor receptor (EGFR). The at least one targeting domain may be configured to bind variants or mutants of the EGFR receptor. In some embodiments, the at least one targeting domain is configured to bind EGFRvIII, a deletion mutant of the EGFR receptor.

[0043] The targeting domain may comprise any length or structure of polypeptide that allows binding to a target of interest. The targeting domain may be an antibody or antibody mimetic. Antibody mimetics are organic compounds that can specifically bind antigens, like an antibody, but are not structurally related to antibodies. Often they are artificial polypeptides or proteins with a molar mass much smaller (3-20 kDa) than that of antibodies (-150 kDa). Examples of antibody mimetics include Affibody domains, Affilins, Affimers, Affitins, Alphabodies, Anticalins, Avimers, DA R Pi ns Fynomers, Kunitz domain peptides, Monobodies, and nanoCL AMPS .

[0044] The at least one targeting domain may comprise an Affibody domain. Affibody domains are comprised of triple helical, small (-7 kDa) scaffold proteins derived from the IgG- binding (Z) domain of S. aureus that have been engineered to bind unique targets with high affinity, comparable to that of monoclonal antibodi es but with the greater ease of genetic manipulation possible with a bacterial expression system. These proteins are highly stable without disulfide bonds, expressed in high yield, and amenable to head-to-tail genetic fusions and combinations for multiplexed targeting.

[0045] In some embodiments, the conjugate may include at least one, at least two, at least three, at least four, at least five, at least six, at least seven, at least eight, at least nine, or at least ten Affibody domains. In some embodiments, the conjugate may include less than two, less than three, less than four, less than five, less than six, less than seven, less than eight, less than nine, or less than ten Affibody domains. In some exemplary embodiments, the conjugates include one, two or four Affibody domains.

[0046] The targeting domain may comprise any sequence of ammo acids that allows binding to a target of interest. In some embodiments, the targeting domain comprises an amino acid sequence of

GVDNKFNKEMWAAWEEIRNLPNLNGWQMTAFIASLVDDPSQSANLLAEAKKLNDAQA PKG (SEQ ID NO: 1).

b) Thermally Responsive Biopolymer |Ό047] The biopolymer-immunotoxin polypeptide conjugate may include a thermally responsive biopolymer. The thermally response biopolymer may comprise an elastin-like polypeptide. Elastin-like polypeptides (ELP) are thermally responsive polypeptides comprising the pentapeptide repeat sequence (VPGXG)n (SEQ ID NO: 7), wherein X is any ammo acid except proline and n is an integer between 1 and 500. In some embodiments, the elastin-like polypeptide comprises an ammo acid sequence of (VPGXGjn (SEQ ID NO: 7), wherein n is 1 to 500 and X is any amino acid except proline, or a combination thereof.

[0048] n may be from 1 to 500, from 1 to 400, from 1 to 300, from 1 to 200, from 1 to 100, from 1 to 50, from 1 to 25, from 1 to 10, from 50 to 500, from 50 to 400, from 50 to 300, from 50 to 200, from 50 to 100, from 100 to 500, from 100 to 400, from 100 to 300, from 100 to 200, from 200 to 500, from 200 to 400, from 200 to 300, from 200 to 500, from 300 to 500, from 300 to 400, or from 400 to 500. In certain embodiments, n is 60.

[0049] The elastin-like polypeptide may comprise an amino acid sequence of (VPGXGjn (SEQ ID NO: 7), wherein X is valine (V), alanine (A), or a combination thereof. In some embodiments, X is a combination of value and alanine at a V : A ratio of 4: 1. In exemplary embodiments, the elastin-like polypeptide comprises an amino acid sequence of (VPGVGjeo (SEQ ID NO: 2). In exemplary embodiments, the elastin-like polypeptide comprises an ammo acid sequence of (VPGV4: AIG)6O (SEQ ID NO: 3). In exemplary embodiments, the elastin-like polypeptide comprises an ammo acid sequence of (VPGAGjeo (SEQ ID NO: 4).

[0050] As a result of the thermally responsive polypeptide, the biopolymer-immunotoxin polypeptide conjugate may have phase transition behavior. Phase transition may refer to the aggregation, which may occur sharply and in some instances reversibly at or above the transition temperature. Tins phase transition behavior may allow the biopolymer-immunotoxin polypeptide conjugate to form a gel-like depot upon administration to a subject. The Tt can be adjusted by vary ing the amino acid sequence of the elastin-like polypeptide, by varying the length of the polypeptide, or a combination thereof.

[0051] The biopolymer-immunotoxin polypeptide conjugate may have a transition temperature (Tt) above 20 °C at a concentration of 0.5 - 1000 mM. The transition temperature may be above 20 °C, 25 °C, 30 °C, 35 °C, 40 °C, or 45 °C at a concentration of 0.5 - 1000 mM. The transition temperature may be below 50 °C, 45 °C, 40 °C, 37 °C, 35 °C, 30 °C, or 25 °C at a concentration of 0.5 - 1000 mM. The transition temperature may be above 20 °C at a concentration greater than 1 mM, greater than 10 mM, greater than 50 mM, greater than 100 mM, greater than 200 mM, greater than 300 mM, greater than 400 mM, greater than 500 mM, greater than 600 mM, greater than 700 mM, greater than 800 mM, or greater than 900 mM. The transition temperature may be above 20 °C at a concentration less than 1000 mM, less than 900 mM, less than 800 mM, less than 700 mM, less than 600 mM, less than 500 mM, less than 400 mM, less than 300 mM, less than 200 mM, less than 100 mM, less than 50 mM, less than 10 mM, or less than 1 mM.

[0052] This phase transition behavior may allow the biopolymer-immunotoxin polypeptide conjugate to form a gel-like depot upon administration to a subject. The depot wall have the highest concentration of drug in the center, at the site of injection, and a decreasing concentration gradient towards the perimeter. Since the transition temperature is concentration dependent, the thermally responsive polypeptide may allow the gel-like depot to gradually resolubihze at the low concentration perimeter of the depot and slowly release the biopolymer-immunotoxin polypeptide conjugate into the surrounding tissue.

[0053] Phase transition behavior may also enable purification of the conjugate using inverse transition cycling. “Inverse transition cycling” refers to a protein purification method for polypeptides having phase transition behavior, and the method may involve the use of the conjugate’s reversible phase transition behavior to cycle the solution through soluble and insoluble phases, thereby removing contaminants and eliminating the need for chromatography. c) Bacterial Toxin

[0054] The biopolymer-immunotoxin polypeptide conjugate may include a bacterial toxin. The bacterial toxin may comprise any enzymatically active toxin of bacterial origin or an enzymatically active fragment of such a toxin. Toxin variants can be engineered to maintain the enzymatically active fragment of the toxin but remove the natural targeting domain or immune cell epitopes for reduction of immunogemcity. Examples of enzymatically active toxins and fragments thereof include cholera toxin, Staphylococcal a-hemolysin, Staphylococcal d~ hemolysin, Vibrio thermostable direct hemolysin, pertussis toxin, exotoxin A (from

Pseudomonas aeruginosa), Shiga toxin, anthrax toxin, Botulinum toxins, tetanus toxin, diphtheria toxin, Pneumoiysin, Streptolysin O, or E. coli heat-labile toxin in some embodiments, the bacterial toxin comprises Pseudomonas aeruginosa exotoxin A. |Ό055] The toxin may function by a number of mechanisms. Some toxins may function by inactivating protein synthesis within the cell which leads to the death of the cell. For example, Pseudomonas aeruginosa exotoxin A and diphtheria toxin inhibit protein translation by inhibiting ribosome translocation.

[0056] In some embodiments, the toxin comprises a variant. In some embodiments, the toxin comprises a variant of Pseudomonas aeruginosa exotoxin A, LOIOR, that lacks the natural targeting domain as well as B- and T-cell epitopes for both mice and humans. In exemplary- embodiments, the bacterial toxin comprises an ammo acid sequence of

KASGGRHRQPRGWEQLGGSPTGAEFLGDGGDVSFSTRGTQNWTVERLLQAHAQLEER

GYVFVGYHGTFLEAAQSrVFGGVAARSQDLAAIWAGFYIAGDPALAYGYAQDQEPDAA

GRIRNGALLRVYVPASSLPGFYRTSLTLAAPEAAGEVERLIGHPLPLALDAITGPEEEGGR

LETILGWPLAERTWIPSAIPTDPRNVGGDLDPSSIPDKEQAISALPDYASQPGKPPREDLK

(SEQ ID NO: 5).

d) Conjugate Design

[0057] The biopo!ymer-immunotoxin polypeptide conjugate may be formed from expression of a single polypeptide chain or from multiple polypeptide chains linked, or coupled, together after individual expression and purification of each of the components. In some embodiments, the polypeptide conjugation is expressed and purified as a single polypeptide chain, such as a fusion protein.

[0058] The at least one targeting domain, the thermally responsive biopolymer, and the bacterial toxin may be conjugated together in different orientations. For example, the targeting domain may be on the N-terminus of the conjugate with the bacterial toxin on the C-terminus or the targeting domain may be on the C-terminus of the conjugate with the bacterial toxin on the N-terminus or the bacterial toxin may be on the N-terminus of the conjugate with the thermally responsive biopolymer on the C-terminus. In some embodiments, the bacterial toxin is on the C- terminus of the biopolymer-immunotoxin polypeptide conjugate. In some embodiments, the N- termmus of the bacterial toxin is coupled to the thermally responsive biopolymer.

[0059] As will be readily apparent to one skilled in the art, certain bacterial toxins require a free, or unconjugated, N- or C-terminus for proper functionality. In these instances, one of skill in the art would understand how to design the biopolymer-immunotoxin polypeptide conjugate to ensure functionality of the bacterial toxin.

[0060] The biopolymer-immunotoxin polypeptide conjugate may further comprise one or more linkers. The linkers may be between the any two of the bacterial toxin, the thermally responsive biopolymer and the at least one targeting domain. For example, when the N-terminus of the bacterial toxin is coupled to the thermally responsive biopolymer, a linker may be between the N-terminus of the bacterial toxin and the C-termmus of the thermally responsive biopolymer.

[0061] The linkers may comprise any amino acid sequence. The linkers may be flexible such that they do not constrain either of the two components they link together in any particular orientation. The linkers may essentially act as a spacer. The linker may be cleavable by enzymes, small molecules, or changes in environmental conditions, such as pH or oxidation level. In some embodiments, the one or more linkers comprises an amino acid sequence of GGGSGGGSGGGS (SEQ ID NO: 6).

3. Methods of Use

[0062] The present disclosure also provides methods of treating cancer. One of the methods comprises administering to a subject in need thereof a therapeutically effective amount of the conjugate or a pharmaceutical composition comprising the conjugate as detailed herein to the subject.

[0063] The compositions as detailed herein may be used to treat any cancer type or subtype. The cancer may be a carcinoma, sarcoma, lymphoma, leukemia, melanoma, mesothelioma, multiple myeloma, or seminoma. The cancer may be a cancer of the bladder, blood, bone, brain, breast, cervix, colon/rectum, endometrium, head and neck, kidney, liver, lung, muscle tissue, ovary, pancreas, prostate, skin, spleen, stomach, testicle, thyroid or uterus.

[0064] In some embodiments, the cancer is a solid tumor. Examples of cancers that are solid tumors include, but are not limited to, brain, pancreatic, bladder, non-small cell lung cancer (NSCLC), breast and ovarian cancers. In some embodiments, the cancer is glioblastoma.

[0065] The composition may be administered locally to the cancer, such as intratumoral .

4, Administration and Dosing

[0066] The disclosed compositions may be incorporated into pharmaceutical compositions suitable for administration to a subject (such as a patient, winch may be a human or non-human) well known to those skilled in the pharmaceutical art. The pharmaceutical composition may be prepared for administration to a subject. Such pharmaceutical compositions may be

administered in dosages and by techniques well known to those skilled in the medical arts taking into consideration such factors as the age, sex, weight, and condition of the particular subject, and the route of administration.

[0067] The pharmaceutical compositions may include pharmaceutically acceptable carriers. The term“pharmaceutically acceptable carrier,” as used herein, means a non-toxic, inert solid, semi-solid or liquid filler, diluent, encapsulating material or formulation auxiliary of any type. Some examples of materials which can serve as pharmaceutically acceptable carriers are sugars such as, but not limited to, lactose, glucose and sucrose; starches such as, but not limited to, corn starch and potato starch; cellulose and its derivatives such as, but not limited to, sodium carboxymethyi cellulose, ethyl cellulose and cellulose acetate; powdered tragacanth; malt;

gelatin; talc; excipients such as, but not limited to, cocoa butter and suppository waxes; oils such as, but not limited to, peanut oil, cottonseed oil, safflower oil, sesame oil, olive oil, corn oil and soybean oil; glycols; such as propylene glycol; esters such as, but not limited to, ethyl oleate and ethyl laurate; agar; buffering agents such as, but not limited to, magnesium hydroxide and aluminum hydroxide; algimc acid; pyrogen-free water; isotonic saline; Ringer's solution; ethyl alcohol, and phosphate buffer solutions, as well as other non-toxic compatible lubricants such as, but not limited to, sodium lauryl sulfate and magnesium stearate, as well as coloring agents, releasing agents, coating agents, sweetening, flavoring and perfuming agents, preservatives and antioxidants may also be present in the composition, according to the judgment of the formulator. The route by which the composition is administered and the form of the composition will dictate the type of carrier to be used.

[0068] The compositions disclosed herein may be administered prophylactically or therapeutically. In prophylactic administration, the composition may be administered in an amount sufficient to induce a response. In therapeutic applications, the composition is administered to a subject in need thereof m an amount sufficient to elicit a therapeutic effect. An amount adequate to accomplish this is defined as“therapeutically effective dose.” Amounts effective for this use will depend on, e.g., the particular composition of the conjugate regimen administered, the manner of administration, the stage and severity of the disease, the general state of health of the patient, and the judgment of the prescribing physician. [0069] The compositions disclosed herein may be administered by methods well known in the art as described in Donnelly et al. {Ann. Rev. Immunol. 1997, 15, 617-648); Feigner et al. (U.S. Patent No. 5,580,859, issued Dec. 3, 1996); Feigner (U.S. Patent No. 5,703,055, issued Dec. 30, 1997); and Carson et al. (U.S. Patent No. 5,679,647, issued Oct. 21, 1997). One skilled in the art would know that the choice of a pharmaceutically acceptable earner, including a physiologically acceptable compound, depends, for example, on the route of administration.

[0070] The compositions disclosed herein may conveniently be presented in a single dose or as divided doses administered at appropriate intervals, for example, as two, three, four or more sub-doses per day. The sub-dose itself may be further divided, e.g., into a number of discrete loosely spaced administrations.

[0071] As will be readily apparent to one skilled in the art, the useful in vivo dosage to be administered and the particular mode of administration will vary depending upon the age, weight, the severity of the affliction, and mammalian species treated, the particular compounds employed, and the specific use for which these compounds are employed. The determination of effective dosage levels, that is the dosage levels necessary' to achieve the desired result, can be accomplished by one skilled in the art using routine methods, for example, human clinical trials, in vivo studies and in vitro studies.

[0072] Dosage amount(s) and intervai(s) may be adjusted individually to provide plasma levels of the molecule which are sufficient to maintain the modulating effects, or minimal effective concentration (MEC). The MEC will vary for each molecule but can be estimated from in vivo and/or in vitro data. Dosages necessary to achieve the MEC will depend on individual characteristics and route of administration. However, assays well known to those in the art may be used to determine plasma concentrations. Dosage intervals can also be determined using MEC value. Compositions should be administered using a regimen which maintains plasma levels above the MEC for 10-90% of the time, preferably between 30-90% and most preferably between 50-90%. in cases of local administration or selective uptake, the effective local concentration of the drug may not be related to plasma concentration.

[0073] It should be noted that the attending physician would know how to and when to terminate, interrupt, or adjust administration due to toxicity or organ dysfunctions. Conversely, the attending physician would also know to adjust treatment to higher levels if the clinical response were not adequate (precluding toxicity). The magnitude of an administrated dose in the management of the disorder of interest will vary with the severity of the symptoms to be treated and the route of administration. Further, the dose, and perhaps dose frequency, will also vary according to the age, body weight, and response of the individual patient. A program comparable to that discussed above may be used in veterinary medicine.

[0074] A therapeutically effective amount of the compositions may be administered alone or m combination with a therapeutically effective amount of at least one additional therapeutic agents. In some embodiments, effective combination therapy is achieved with a single composition or pharmacological formulation that includes both agents, or with two distinct compositions or formulations, administered at the same time, wherein one composition includes a compound of this invention, and the other includes the second agent(s). Alternatively, in other embodiments, the therapy precedes or follows the other agent treatment by intervals ranging from minutes to months.

[0075] A wide range of second therapies may be used in conjunction with the compounds of the present disclosure. The second therapy may be a combination of a second therapeutic agent or may be a second therapy not connected to administration of another agent. Such second therapies include, but are not limited to, surgery, immunotherapy, radiotherapy, or administration of a chemotherapeutic agent.

5, Examples

[0076] It will be readily apparent to those skilled in the art that other suitable modifications and adaptations of the present disclosure described herein are readily applicable and appreciable, and may be made using suitable equivalents without departing from the scope of the present disclosure or the aspects and embodiments disclosed herein. Having now described the present disclosure in detail, the same will be more clearly understood by reference to the following examples, which are merely intended only to illustrate some aspects and embodiments of the disclosure, and should not be viewed as limiting to the scope of the disclosure. The disclosures of all journal references, U.S. patents, and publications referred to herein are hereby incorporated by reference in their entireties. Example 1: AffETx Library Expression and Purity

[0077] The present disclosure provides, in part, a novel combination of three proteins (at least one targeting domain, a thermally responsive biopolymer, and a bacterial toxin) into one biopolymer-immunotoxin polypeptide conjugate termed AffETx.

[0078] in one example of a targeting domain, an Affibody (ZEGFR: 1907) specific for the epidermal growth factor receptor (EGFR), a receptor upregulated in GBM and undetectable m healthy adult brain, was used. EGFR is the most frequently amplified gene in GBM, the extent to which defines this cancer’s subtype. It was also determined that this Affibody recognizes EGFRvIII, a GBM-specific deletion mutant EGFR receptor that is constitutively active, overexpressed in GBM, and has a distinct epitope from EGFR. The affinity of the Affibody ZEGFR: 1907 for EGFR as a monomer was previously determined to be 5.4 nM as a monomer and 1.6 nM as a dimer for the extracellular domain of the receptor. Given the benefit of increasing affinity through multivalency, the AffETx may comprise more than one Affibody domain.

[0079] In one example of a thermally responsive biopolymer, an elastin-!ike polypeptide (ELP) provides AffETx with the ability to form a gel-like depot upon injection intratumorally. This depot will gradually dissolve and release AffETx molecules into the tumor and surrounding tissue via diffusion. ELPs reversibly phase separate in aqueous solution when heated above a characteristic transition temperature (Tt) to form micron-size aggregates which resolubilize completely upon cooling. ELPs may be fused to other proteins and peptides at their N- or C- terminus, or both, without loss of thermal responsivity. Sustained release ELP depots specifically designed for use in vivo are stable over a period of up to 10 days in mice, and up to 20 days in non-human primates.

[0080] One example of a bacterial toxin is derived from P aeruginosa exotoxin A. This toxin potently inhibits protein translation by ADP-ribosylating and inactivating elongation factor-2; a single molecule is enough to kill an entire target cell. This variant was engineered to remove its natural targeting domain as well as B- and T-cell epitopes for both mice and humans to reduce systemic immunogemcity (LO10R). Truncated toxins are non-toxic without the addition of an exogenous targeting domain, which was provided by the targeting domain.

[0081] T he AffETx library was constructed by genetic fusion of one, two, or four Affibody domains comprising the ammo acid sequence of SEQ ID NO: 1, an ELP comprising the ammo acid sequence of SEQ ID NO: 2, SEQ ID NO: 3, or SEQ ID NO: 4, a flexible linker comprising the amino acid sequence of SEQ ID NO: 5, and a toxin comprising the amino acid sequence of SEQ ID NO: 6 m sequence from N- to C-terminus (FIG. 1, Tables 1 and 2).

Table 1: AffETx Library Constructs and Controls

Table 2; AffETx Library Constructs and Controls

[0082] These constructs were expressed in Escherichia coli and purified from inclusion bodies. Briefly, the inclusion bodies were washed first with 50 mM Tris HC1, pH 8.0/10 mM EDTA/1.5 M NaC!/0.5% Triton X-l 00 and then 50 mM Tris 1 IC!. pH 8.0/10 mM EDTA/1 5 M Nad. The insoluble fraction was then denatured using 6 M guanidine hydrochloride, pH 1.5 and dialyzed into 50 mM Tris HC1, pH 8.0/150 mM NaCI/10 mM EDTA/0.1 mM

phenylmethylsulfonyl fluoride/0.5 mM benzamidine hydrochloride to allow for protein refolding. AffETx purity was refined by using size exclusion chromatography and the library purity_' assessed using SDS-PAGE (FIG 2).

[0083] The relevant controls were also expressed to allow' assessment of the cytotoxic effects of either just the Affibody or just the toxin fused to an ELP. The Affibody-ELP controls were expressed m the soluble fraction and purified using inverse transition cycling, a non

chromatographic method of purifying thermally responsive ELPs as previously described. The ELP-toxm controls required refolding as they were expressed in inclusion bodies. All proteins were dialyzed into phosphate-buffered saline (PBS) and aliquoted for long-term storage at -80°C.

[0084] The AffETx library was assessed for cytotoxicity in a panel of relevant cell lines. First, murine 3T3 fibroblasts transfected by EGFR (FIG. 3A), EGFRvIII (FIG. 3B), or a negative control (null, FIG. 3C) were tested in cell viability' assays with AffETx.

[0085] The fibroblasts were seeded at a density of 2,500 cells/well in a 96-well plate in a 90 mΐ volume of complete zinc option- 10% FBS media (Improved Modified Eagle Medium, Richter’s Modification) and incubated overnight at 37°C with 5% CO2. The cells were then treated with 10 pL media containing the serial dilution of AffETx or a control and incubated for 72 hours. The treatments were done in triplicate to account for technical variability. After 72 hours, the Promega CellTiter 96® AQueous One Solution Cell Proliferation Assay (MTS) reagent was used according to manufacturer’s instructions to assay the number of viable cells. The cell viability was determined using measurements of absorbance at two wavelengths (490 nm and 650 nm) using a plate reader. The dose response curves were generated by plotting percent viable cells versus protein concentration (AffETx or control protein). The dose response curve was approximated from the scatter plot using a four-parameter logistic model calculation, and EC50 (FIG. 3D) was calculated as the concentration of AffETx required to kill 50% of the cells.

[0086] The AffETx library and controls were then similarly tested in established human GBM lines, D270MG (FIG. 4 A) and A172 (FIG. 4B), and murine GBM lines, CT-2A (FIG. 7 A) and SMA560 (FIG. 7B). Cell lines were seeded at a density of 2,500 cells/well in a 96-well plate in a 90 pL volume of complete media. D27QMG cells were seeded and maintained in complete zinc option- 10% FBS media (Improved Modified Eagle Medium, Richter’s Modification) media. A172 cells were seeded and maintained m complete Dulbecco’s Modified Essential Medium supplemented with 10% FBS and high glucose. The seeded cells were incubated overnight at 37°C with 5% CCh and then treated with 10 pL media containing the serial dilution of AffETx or a control and incubated for 72 hours. The treatments w¾re done in triplicate to account for technical variability. After 72 hours, the Promega CellTiter 96® AQueous One Solution Cell Proliferation Assay (MTS) reagent was used according to manufacturer’s instructions to assay the number of viable cells. The cell viability was determined using measurements of absorbance at two wavelengths (490 nm and 650 nm) using a plate reader. The dose response curves were generated by plotting percent viable cells versus protein concentration (AffETx or control protein). The dose response curve was approximated from the scatter plot using a four-parameter logistic model calculation, and ECso was calculated as the concentration of AffETx required to kill 50% of the cells.

The binding of the Affibody for EGFR was confirmed using 3T3 fibroblasts transfected with EGFR (FIG 5 A), and for the binding of the Affibody on explanted xenograft cells (FIG. 5B).

[0088] (ZEGFR)2-ELPA was fluorescentiy labeled at its N-termmus with Alexa488-NHS ester and purified to remove excess free dye. D270MG xenograft cells were used to establish subcutaneous tumors in nude BALB/C mice, which were then removed by dissection, homogenized, and processed into a single cell suspension with collagenase and red blood cell lysis buffer. These were washed twice in PBS/1% BSA and after the final wash, resuspended in PBS/1% BSA at a cell density of 2 x 10⁶ cells ml, ¹. The transfected fibroblasts were trypsmized and resuspended in PBS/1% BSA at a final cell density of 2 x 10° cells ml/¹. Both cell lines were incubated with Alexa488-(ZEGFR)₂-ELPA at a concentration of 20 mM for 1 hour at 4°C and then washed three times and analyzed using a flow cytometer for population fluorescence.

The thermal responsivity of the AffETx library was assessed via UV-vis spectroscopy at a range of relevant concentrations as the thermally-triggered coacervation of ELP results in a visual change in turbidity (FIG. 6).

[009Q] The concentration of the AffETx components was measured by a NanoDrop spectrophotometer and the stock solutions diluted in PBS to achieve the desired concentrations. These samples were heated at 1°C min and the optical turbidity at 350 nm recorded every 1°C. The transition temperature, Tt, was then determined as the maximum of the first derivative of the turbidity as a function of temperature. This data was used to construct semi-log plots of Tt versus concentration for each construct to provide a visual illustration of the relationship between injection concentration and depot dissolution rate as the concentration decreases and Tt increases.

Example 4: In vivo Efficacy

[0091] The in vivo efficacy of AffETx constructs was tested in immunocompetent eight- week-old C57BL/6 female mice (Jackson Laboratories, Bar Harbor, ME) with a syngeneic GBM tumor model, CT-2A-dmEGFRvJJJ-Luc (provided by Darell Bigner, Duke University). To establish orthotopic tumors, the mice were anesthetized with a continuous isoflurane vaporizer (2.5% isoflurane in 2 L min ¹) and then secured in a Stoeltmg stereotactic frame. The anterior cranial region was shaved and after disinfecting the area with Betadme, a 1 cm midline incision was made in the skin over the skull. The bregma was located and used to determine the coordinates for injection (0.5 mm anterior; 2 mm lateral). A sterile pencil was used to mark the coordinates and a Dremel 105 engraving cutter was used to gently break through the animal’s skull. A mounting holder/stereotaxic injector on the frame held a Hamilton syringe containing the cell suspension m a PBS solution containing 3% methylcelJulose (Sigma Aldrich, St. Louis, MO). A sterile 27G needle attached to the syringe was introduced through the skull and into the brain at a depth of 3.3 mm from the dura mater. CT-2A ceils (2 x 10⁵) were then injected in a volume of 5 pL at a rate of 3.33 pL min⁴. After injection and a 1 min delay, the syringe was removed, and a small amount of bone wax placed to occlude the hole. The mouse was removed from the frame and the skin was closed using Vetbond tissue adhesive (Santa Cruz Animal Health, Dallas, TX).

[0092] After five days, the mice ware randomized into groups by tumor size. The tumors were visualized by luminescence and the total flux quantified using an I VIS Lumina Series III imager (PerkinElmer, Waltham, MA). These values were correlated to tumor size and the groups accordingly stratified; after five days with this model, the tumors reach an approximate spherical volume of 0.5 mm³. The next day, six days after tumor inoculation, groups were then locally treated with AffETx, controls, or vehicle (lxPBS) directly injected into the established tumors. The mice were oriented in the stereotactic frame as before and the incision site located according to the original coordinates. The endotoxin-purified AffETx or control solutions were then injected intratumoraJly in a volume of 10m1 at a rate of 3 m! nun ¹. After treatment, the mice were weighed and monitored daily for signs of distress until humane endpoints were reached or the termination of the study, on day 60. Overall survival and body w^reight changes were recorded for each of the treatment groups. Cumulative survival curves were compared using Kaplan-Meier analysis followed by the Mantel-Cox log rank test.

[0093] First, the maximum tolerated dose (MTD) of AffETx was identified with this tumor model to develop an understanding of the therapeutic window for this drug. Drug-induced toxicity will present in the mice within 72 h after treatment and will present as neurological distress (hunching, ataxia, lethargy), rapid weight loss, or sudden death. These symptoms will intensify over the course of the three days post-treatment and require humane euthanasia. In this study, none of the treatment groups exhibited drug-related toxicity and all deaths at later time points can be attributed to tumor-related toxicity. While the MTD from these doses was unable to be assessed, significant improvement to median and overall survival in several of the treatment groups was observed (FIGS. 8A-8B).

[0094] These results bolstered confidence in the effectiveness of AffETx and suggested that additional fine-tuning of the depot release kinetics was needed to achieve sustained-release, with the expectation of improving survival even beyond that observed with the soluble formulation. This hypothesis, coupled with the lack of identification of the MTD from these doses, provided the motivation for a follow-up in vivo study with dose escalation and additional depot-forming AffETx

[0095] In the second animal study, there were several goals: 1) assess the replicability of the best-performing soluble AffETx construct; 2) identify the MTD; 3) compare our treatment to an existing immunotoxm currently in clinical trials, D2C7; and 4) identify the best-performing depot formulation. For the latter, a second depot-forming dimeric AffETx candidate ((ZEGFR)?- ELPB-toxin) was introduced, as tins construct exhibited a less hydrophobic profile than ELPA and also had a different rate of release as the inverse log-linear relationship between Tt and concentration, and therefore dilution profile, had a more negative slope indicating both a weaker depot and more rapid release.

[0096] Both the (ZEGFR)2-ELPA-toxin and (ZEGFR)₂-ELPB-toxin constructs at a dose of 45 mM resulted in rapid, significant body weight loss and co-incident morbidity' within the first 72 h following treatment. Whether this dose is also the MTD will require further investigation, but this dose importantly provided an upper-bound for the therapeutic window (FIGS. 9A-9B).

[0097] All of the in vivo data, from both tins study and the first, was evaluated in the context of a clinically used immunotoxin, D2C7. This immunotoxin w¾s developed and generously provided by Darell Bigner, Duke University, and is comprised of a single chain variable fragment (scFv) specific for EGFR/EGFRvIII linked to a previous generation of P. aeruginosa exotoxm A with immunogenic epitopes still intact. In both clinical trials and pre-clinical testing, D2C7 is administered orthotopically through use of an osmotic pump implanted in the brain for 24 h to seven days.

[0098] Considering the results from the two depot-forming AffETx constructs investigated in both of these MTD studies, the best performing group was that of (ZEGFR)2~ELpA~toxin, at a dose of 5 mM. This treatment group significantly improved overall survival with a median survival of 21.5 days.

[0099] For reasons of completeness, various aspects of the invention are set out in the following numbered clauses:

[00100] Clause 1. A biopolymer-immunotoxin polypeptide conjugate comprising at least one targeting domain, a thermally responsive biopolymer; and a bacterial toxin.

[00101] Clause 2. The conjugate of clause 1, wherein the at least one targeting domain is configured to bind to the epidermal growth factor receptor (EGFR).

[00102] Clause 3. The conjugate of clause 2, wherein the EGFR is EGFRvIII.

[00103] Clause 4. The conjugate of any of clauses 1-3, wherein the at least one targeting domain comprises an Affibody domain.

[00104] Clause 5. The conjugate of any of clauses 1-4, wherein the at least one targeting domain comprises two or four Affibody domains.

[00105] Clause 6. The conjugate of any of clauses 1-5, wherein the at least one targeting domain comprises an ammo acid sequence of

GVDNKFNKEMWAAWEEIRNLPNLNGWQMTAFIASLVDDPSQSA LLAEAKKLNDAQA PKG (SEQ ID NO: 1).

[00106] Clause 7. The conjugate of any of clauses 1-6, wherein the thermally responsive biopolymer comprises an elastin-like polypeptide (ELP). [00107] Clause 8. The conjugate of clause 7, wherein the elastin-like polypeptide comprises an amino acid sequence of (VPGXG)n (SEQ ID NO: 7), wherein n is 1 to 500 and X is any ammo acid except proline, or a combination thereof.

[00108] Clause 9. The conjugate of clause 8, wherein X is val e, alanine or V: A at a ratio of

4: 1.

[00109] Clause 10. The conjugate of clause 8 or clause 9, wherein n is 60.

[00110] Clause 11. The conjugate of any of clauses 8-10, wherein the ELP comprises an amino acid sequence of (VPGVGjso (SEQ ID NO: 2).

[00111] Clause 12. The conjugate of any of clauses 8-10, wherein the ELP comprises an ammo acid sequence of (VPGVAAiGEo fSEQ ID NO: 3).

[00112] Clause 13. The conjugate of any of clauses 8-10, wherein the ELP comprises an ammo acid sequence of (VPGAGjeo (SEQ ID NO: 4).

[00113] Clause 14. The conjugate of any of clauses 1-13, wherein the bacterial toxin comprises P. aeruginosa exotoxin A, or a portion thereof.

[00114] Clause 15. The conjugate of any of clauses 1-14, wherein the bacterial toxin comprises an amino acid sequence of

KASGGRHRQPRGWEQLGGSPTGAEFLGDGGDVSFSTRGTQNWTVERLLQAHAQLEER

GYVFVGYHGTFLEAAQSIVFGGVAARSQDLAAIWAGFYIAGDPALAYGYAQDQEPDAA

GRIRNGALLRVYVPASSLPGFYRTSLTLAAPEAAGEVERLIGHPLPLALDAITGPEEEGGR

LETiLGWPLAERTVVIPSAIPTDPRNVGGDLDPSSiPDKEQAISALPDYASQPGKPPREDLK (SEQ ID NO: 5).

[00115] Clause 16. The conjugate of any of clauses 1 -15, wherein the bacterial toxin is on the C-terrmnus of the biopolymer-immunotoxin polypeptide conjugate.

[00116] Clause 17. The conjugate of any of clauses 1-16, wherein the N-terminus of the bactenal toxin is coupled to the thermally responsive biopolymer.

[00117] Clause 18. The conjugate of any of clauses 1-17 further comprising one or more linkers.

[00118] Clause 19. The conjugate of clause 18, wherein the one or more linkers comprises an amino acid sequence of GGGSGGGSGGGS (SEQ ID NO: 6).

[00119] Clause 20. The conjugate of any of clauses 1-19, wherein the conjugate has a transition temperature (Tt) above 20 °C at a concentration of 0.5 - 1000 mM. [00120] Clause 21. A pharmaceutical composition comprising the conjugate of any of clauses 1 20

[00121] Clause 22. A method of treating cancer comprising administering to a subject in need thereof a therapeutically effective amount of the conjugate of any of clauses 1-20 or the pharmaceutical composition of clause 21.

[00122] Clause 23. The method of clause 22, wherein the cancer is a solid tumor.

[00123] Clause 24. The method of clause 22 or 23, wherein the cancer is glioblastoma.

[00124] Clause 25. A biopolymer-immunotoxin conjugate comprising, starting from the N- terminus, a targeting domain, a thermally responsive biopolymer, and a bacterial toxin.

[00125] Clause 26. The conjugate according to clause 25, in which the targeting domain comprises at least one Affibody domain.

[00126] Clause 27. The conjugate according to clause 26 in which the targeting domain comprises (ZEGFR: 1907) having an amino acid sequence of

GVDNKFNKEMWAAWEEIRNLPNLNGWQMTAFIASLVDDPSQSA LLAEAKKLNDAQA

PKG (SEQ ID NO: 1).

[00127] Clause 28. The conjugate according to clause 25 in which the thermally responsive biopolymer comprises an elastm-like protein (ELP).

[00128] Clause 29. The conjugate according to clause 28 in which the ELP comprises an amino acid sequence of (VPGVGjeo (SEQ ID NO: 2).

[00129] Clause 30. The conjugate according to clause 28 in which the ELP comprises an amino acid sequence of (VPGV4:A1G)60 (SEQ ID NO: 3)

[00130] Clause 31 . The conjugate according to clause 28 in which the ELP comprises an amino acid sequence of (VPGAG)eo (SEQ ID NO: 4)

[00131] Clause 32. The conjugate according to clause 25 in which the bacterial toxin comprises P. aeruginosa exotoxin A, or a portion thereof.

[00132] Clause 33. The conjugate according to clause 32 in which the bacterial toxin comprises LO10R having an amino acid sequence of

KASGGRHRQPRGWEQLGGSPTGAEFLGDGGDVSFSTRGTQNWTVERLLQAHAQLEER

GYVFVGYHGTFLEAAQSIVFGGVAARSQDLAAIWAGFYIAGDPALAYGYAQDQEPDAA

GRIRNGALLRVYVPASSLPGFYRTSLTLAAPEAAGEVERLIGHPLPLALDA1TGPEEEGGR LETILGWPLAERTVVIPSAIPTDPRNVGGDLDPSS1PDKEQAISALPDYASQPGKPPREDLK

(SEQ ID NO: 5).

[00133] Clause 34. The conjugate according to clause 25 in which the conjugate further comprises one or more linkers between the target domain, ELP, and/or bacterial toxin.

[00134] Clause 35. The conjugate according to clause 34 in which the linker comprises a flexible linker.

[00135] Clause 36. The conjugate according to clause 35 in which the linker comprises an amino acid sequence of GGGSGGGSGGGS (SEQ ID NO: 6).

[00136] Clause 37. A pharmaceutical composition comprising a conjugate as m any of the preceding clauses and a pharmaceutically acceptable carrier.

[00137] Clause 38. A method of treating cancer in a subject comprising, administering to the subject a therapeutically effective amount of a conjugate as in any of the preceding claims such that the cancer is treated.

[00138] Clause 39. The method according to clause 38 in which the cancer comprises a glioblastoma.

Claims

CLAIMS What is claimed is:

1. A biopolymer-immunotoxin polypeptide conjugate comprising

at least one targeting domain;

a thermally responsive biopolymer; and

a bacterial toxin.

2. The conjugate of claim l , wherein the at least one targeting domain is configured to bind to the epidermal growth factor receptor (EGFR).

3. The conjugate of claim 2, wherein the EGFR is EGFRviii.

4. The conjugate of claim 1 , wherein the at least one targeting domain comprises an Affihody domain.

5. The conjugate of claim 1 , wherein the at least one targeting domain comprises two or four Affibody domains.

6. The conjugate of claim 1 , wherein the at least one targeting domain comprises an amino acid sequence of

GVDNKFNKEMWAAWEEffiNLPNLNGWQMTAFIASLVDDPSQSANLLAEAKKLNDA QAPKG (SEQ ID NO: 1).

7. The conjugate of claim 1 , wherein the thermally responsive biopolymer comprises an elastin- like polypeptide (ELP).

8. The conjugate of claim 7, wherein the elastin-like polypeptide comprises an amino acid

sequence of (VPGXG)n (SEQ ID NO: 7), wherein n is 1 to 500 and X is any amino acid except proline, or a combination thereof.

9. The conjugate of claim 8, wherein X is valine, alanine or V: A at a ratio of 4: 1.

10. The conjugate of claim 8, wherein n is 60.

11. The conjugate of claim 8, wherein the ELP comprises an amino acid sequence of (VPGVGjeo (SEQ ID NO: 2).

12. The conjugate of claim 8, wherein the ELP comprises an amino acid sequence of

(VPGV 4: AiGj O (SEQ ID NO: 3).

13. The conjugate of claim 8, wherein the ELP comprises an amino acid sequence of (VPGAGjeo (SEQ ID NO: 4).

14. The conjugate of claim 1, wherein the bacterial toxin comprises P. aeruginosa exotoxin A, or a portion thereof.

15. The conjugate of claim 1, wherein the bacterial toxin comprises an amino acid sequence of

KASGGRHRQPRGWEQLGGSPTGAEFLGDGGDVSFSTRGTQNWTVERLLQAHAQLE

ERGYVFVGYHGTFLEAAQSrVTGGVAARSQDLAAIWAGFYIAGDPALAYGYAQDQE

PDAAGRIRNGALLRVYVPASSLPGFYRTSLTLAAPEAAGEVERLIGHPLPLALDAITG

PEEEGGRLETILGWPLAERTVVIPSAiPTDPRNVGGDLDPSSIPDKEQAISALPDYASQ PGKPPREDLK (SEQ ID NO: 5).

16. The conjugate of claim 1, wherein the bacterial toxin is on the C-terminus of the biopolymer- immunotoxin polypeptide conjugate.

17. The conjugate of claim 1, wherein the N-terminus of the bacterial toxin is coupled to the thermally responsive biopolymer.

18. The conjugate of claim 1 further comprising one or more linkers.

19. The conjugate of claim 18, wherein the one or more linkers comprises an amino acid

sequence of GGGSGGGSGGGS (SEQ ID NO: 6).

20. The conjugate of claim 1, wherein the biopolymer-immunotoxin polypeptide conjugate has a transition temperature (Tt) above 20 °C at a concentration of 0.5 - 1000 mM.

21. A pharmaceutical composition comprising the conjugate of claim 1.

22. A method of treating cancer comprising administering to a subject in need thereof a therapeutically effective amount of the conjugate of claim 1 or the pharmaceutical composition of claim 21.

23. The method of claim 22, wherein the cancer is a solid umor.

24. The method of claim 22, wherein the cancer is glioblastoma.