PSMA radiopharmaceutical conjugate and uses thereof

Abstract

The present invention relates to compositions comprising 225Ac labeled anti-PSMA antibody conjugate and the methods of making and using regarding the same. The compositions of the present invention are useful for treating cancer including prostate cancer.

Description

PSMA RADIOPHARMACEUTICAL CONJUGATE AND USES THEREOF CROSS-REFERNCE TO RELATED APPLICATIONS

[0001] The present application claims priority to U.S. Provisional Application 63 / 570,410, filed March 27, 2024. The contents of which are herein incorporated by reference in its entirety.REFERENCE TO AN ELECTRONIC SEQUENCE LISTING

[0002] The contents of the electronic sequence listing (CNTH_010_01WO_SeqList_ST26.xml; Size: 3,013 bytes; and Date of Creation: March 25, 2025) are herein incorporated by reference in its entirety.BACKGROUND OF THE INVENTION

[0003] Prostate cancer (PC) is a significant health burden, with 180,890 new diagnoses and 26,120 deaths in the United States in 2016 alone. Despite advances in diagnostic technology and treatment strategies, up to 40% of patients treated with primary therapy with curative intent will experience disease progression. PC deaths are typically the result of metastatic castration-resistant prostate cancer (mCRPC), and historically the median survival for men with mCRPC has been less than two years. Metastatic castration-resistant prostate cancer (mCRPC) poses a particular clinical challenge in need of additional therapeutic approaches beyond classic androgen deprivation therapies. Chemotherapy compounds docetaxel and cabazitaxel, the androgen receptor signaling inhibitor enzalutamide, CYP-17-inhibitor abiraterone, autologous cellular immunotherapy with sipuleucel-T, and the bone-seeking a-emitter 223Ra have shown improved overall survival (OS) and most have demonstrated quality of life advantages as well. However, these agents have been tested in multiple disease states of mCRPC to determine if or when patients might benefit from each treatment. However, in all cases, these now established therapies become ineffective in controlling tumor progression over time.

[0004] Prostate-specific membrane antigen (PSMA) is a cell surface marker which can be overexpressed in malignant prostate tissues when compared to other organs in the human body such as kidney, proximal small intestine, and salivary glands, and is present and enriched in 75-95% of metastatic castration-resistant prostate cancer (mCRPC). PSMA is also expressed on the neovasculature within many non-prostate solid tumors, including lung cancer, colon cancer, breast cancer, renal cancer, liver cancer, pancreatic cancer, thyroid cancer, transitional cell carcinoma ofthe bladder, neuroendocrine carcinoma, glioblastoma multiforme, melanoma, and non-soft tissue sarcoma, but not on normal vasculature.

[0005] New therapies are urgently needed in order to treat cancers, including PSMA expressing cancers such as prostate cancer

[0006] For example, there is also a need for radiotherapeutic compounds that accumulate to a greater degree in tumors without unacceptable uptake in normal organs, as absorbed dose is a function of the integral of cumulative activity. Though targeted radiotherapy has been practiced for some time using macrocyclic complexes of radionuclides, the macrocycles currently in use (e.g., DOTA) generally form complexes of insufficient stability with radionuclides, particularly for radionuclides of larger size, such as actinium, radium, bismuth, and lead isotopes. There is thus a need for additional therapies for treating PSMA expression cancers and the use of radiotherapeutic compounds for such specific cancers.SUMMARY OF THE INVENTION

[0007] The compositions and pharmaceutical compositions of the present disclosure comprise anti -PSMA antibody conjugates which may be useful in treating various diseases and conditions as disclosed herein. In a specific embodiment, the composition comprises an anti-PSMA antibody or an anti-PSMA antibody fragment, conjugated to a 1,4, 7,10-tetraazacyclododecane- 1,4, 7,10- tetraacetic acid (DOTA) chelator, wherein the DOTA chelator is covalently linked to the anti- PSMA antibody in an average ratio range of about 2 DOTAs per anti-PSMA antibody to about 7 DOTAs per anti-PSMA antibody. In another specific embodiment, the composition comprises an anti-PSMA antibody conjugated to a 1,4, 7,10-tetraazacyclododecane- 1,4, 7, 10-tetraacetic acid (DOTA) chelator. In another specific embodiment, the anti-PSMA antibody is J591. In another specific embodiment, the average ratio range is about 3 DOTAs per anti-PSMA antibody to about 5 DOTAs per anti-PSMA antibody. In another embodiment of the compositions described herein, the anti-PSMA antibody or anti-PSMA antibody fragment comprises: (i) an immunoglobulin heavy chain variable region comprising SEQ ID NO: 1; and (ii) an immunoglobulin light chain variable region comprising SEQ ID NO: 2. In another specific embodiment, the DOTA is conjugated in a 3 arm or 4 arm configuration with the anti-PSMA antibody. In another embodiment, the conjugated anti-PSMA antibody or anti-PSMA antibody fragment is chelated orcomplexed to225Ac. In a specific embodiment, the DOTA is conjugated and chelated or complexed to225Ac, and the anti-PSMA antibody is J591, also known as225Ac labeled J591 tetraxetan.

[0008] In another embodiment of the compositions or pharmaceutical compositions described herein, at least 90% of the anti-PSMA antibody is in the form of a monomer. In another specific embodiment, at least 95% of the anti-PSMA antibody is in the form of a monomer. In another specific embodiment, at least 90% or at least 95% of the anti-PSMA antibody is in the form of a monomer as determined by HPLC-SEC.

[0009] In another embodiment of the compositions or pharmaceutical compositions described herein, at least about 85%, 90%, or 95% of the225Ac activity in the composition is complexed or bound to conjugated anti-PSMA antibody. In another embodiment, at least 96% of the225Ac activity in the composition is complexed or bound to conjugated anti-PSMA antibody. In another embodiment, at least 99% of the225Ac activity in the composition is complexed or bound to conjugated anti-PSMA antibody. In another specific embodiment, the percentage of225Ac activity bound or complexed by the conjugated anti-PSMA antibody is determined by HPLC-SEC. In another specific embodiment, the composition is substantially free of, or contains less than 5% of unchelated, or free,225Ac. In another specific embodiment, the composition is a bulk composition and comprises a total of about 0.25 mCi to about 2.0 mCi from225Ac. In another specific embodiment, the composition comprises a total of about 0.5 mCi to about 1.0 mCi from225Ac.

[0010] In another embodiment, the composition is a pharmaceutical composition and comprises a single unit dose of conjugated anti-PSMA antibody is chelated to225Ac and one or more pharmaceutically acceptable carriers or excipients. In a specific embodiment, the conjugated anti- PSMA antibody is chelated to225Ac. In a specific embodiment, the single unit dose of conjugated anti-PSMA antibody is225Ac-labeled J591 tetraxetan. In another specific embodiment, the composition of a single unit dose comprises a total of about 50 pCi to 350 pCi of225Ac per 20 mg of anti-PSMA antibody. In another embodiment, the composition comprises a single dose ranging from about 25 KBq / kg weight of a patient to about for about 100 KBq / kg weight of a patient. In another specific embodiment, the composition further comprises unconjugated or naked anti- PSMA antibody. In a specific embodiment, the unconjugated or naked anti-PSMA antibody is J591. In another embodiment, the unconjugated / naked anti-PSMA antibody has the same amino acid sequence as the conjugated anti-PSMA antibody. In another embodiment the total anti-PSMAantibody in the composition (unconjugated and conjugated) is at a concentration of 0.8 mg / mL to 1.2 mg / ml. In another embodiment, the amount of the total anti-PSMA antibody in the composition (unconjugated and conjugated) is about 10 mg, about 11 mg, about 12 mg, about 13 mg, about 14 mg, about 15 mg, about 16 mg, about 17 mg, about 18 mg, about 18 mg, about 19 mg, about 20 mg, about 21 mg, about 22 mg, about 23 mg, about 24 mg, about 25 mg, about 26 mg, about 27 mg, about 28 mg, about 29 mg, about 30 mg, about 31 mg, about 32 mg, about 33 mg, about 34 mg, about 35 mg, about 36 mg, about 37 mg, about 38 mg, about 39 mg, or about 40 mg.

[0011] In another specific embodiment, the composition is a pharmaceutical composition and comprises a single unit dose of conjugated anti-PSMA antibody chelated to225Ac wherein the pharmaceutical composition is about 18 to 22 ml in a saline solution containing about l%-2% human serum albumin.

[0012] In another embodiment, the composition of the pharmaceutical composition comprises unconjugated or naked anti-PSMA antibody and conjugated anti-PSMA antibody chelated to225Ac, wherein the ratio of the unconjugated or naked anti-PSMA antibody to conjugated anti- PSMA antibody chelated to225Ac is about 30: 1 by weight, about 29: 1 by weight, about 28:1 by weight, about 27: 1 by weight, about 26: 1 by weight, about 25: 1 by weight, about 24: 1 by weight, about 23: 1 by weight, about 22: 1 by weight, about 21: 1 by weight, about 20:1 by weight, about 19: 1 by weight, about 18: 1 by weight, about 17:1 by weight, about 16:1 by weight, about 15:1 by weight, about 14:1 by weight, about 13:1 by weight, about 12: 1 by weight, about 11: 1 by weight, about 10:1 by weight, about 9: 1 by weight, about 8:1 by weight, about 7: 1 by weight, about 6: 1 by weight, about 5: 1 by weight, about 4: 1 by weight, about 3: 1 by weight, about 2: 1 by weight, about 1 : 1 by weight.

[0013] In another embodiment, the composition of the pharmaceutical composition comprises unconjugated or naked anti-PSMA antibody and conjugated anti-PSMA antibody chelated to225Ac, wherein the ratio of conjugated anti-PSMA antibody chelated to225Ac to unconjugated or naked anti-PSMA antibody is about 30:1 by weight, about 29:1 by weight, about 28:1 by weight, about 27: 1 by weight, about 26: 1 by weight, about 25: 1 by weight, about 24:1 by weight, about 23: 1 by weight, about 22: 1 by weight, about 21 :1 by weight, about 20: 1 by weight, about 19: 1 by weight, about 18:1 by weight, about 17:1 by weight, about 16: 1 by weight, about 15: 1 by weight, about 14: 1 by weight, about 13: 1 by weight, about 12: 1 by weight, about 11 :1 by weight, about10: 1 by weight, about 9:1 by weight, about 8:1 by weight, about 7:1 by weight, about 6: 1 by weight, about 5: 1 by weight, about 4: 1 by weight, about 3: 1 by weight, about 2: 1 by weight, about 1 : 1 by weight.

[0014] In another embodiment, the composition of the pharmaceutical composition comprises unconjugated or naked J591 and225Ac labeled J591 tetraxetan, wherein the ratio of the unconjugated or naked J591 to225Ac labeled J591 tetraxetan is about 30:1 by weight, about 29:1 by weight, about 28:1 by weight, about 27: 1 by weight, about 26:1 by weight, about 25: 1 by weight, about 24: 1 by weight, about 23 : 1 by weight, about 22: 1 by weight, about 21: 1 by weight, about 20: 1 by weight, about 19: 1 by weight, about 18:1 by weight, about 17:1 by weight, about 16: 1 by weight, about 15: 1 by weight, about 14:1 by weight, about 13:1 by weight, about 12:1 by weight, about 11 :1 by weight, about 10:1 by weight, about 9: 1 by weight, about 8:1 by weight, about 7:1 by weight, about 6:1 by weight, about 5:1 by weight, about 4:1 by weight, about 3: 1 by weight, about 2: 1 by weight, about 1 : 1 by weight.

[0015] In another embodiment, the composition of the pharmaceutical composition comprises unconjugated or naked J591 and225Ac labeled J591 tetraxetan, wherein the ratio of the225Ac labeled J591 tetraxetan to unconjugated or naked J591 is about 30: 1 by weight, about 29:1 by weight, about 28:1 by weight, about 27:1 by weight, about 26: 1 by weight, about 25: 1 by weight, about 24: 1 by weight, about 23: 1 by weight, about 22: 1 by weight, about 21 :1 by weight, about 20: 1 by weight, about 19: 1 by weight, about 18:1 by weight, about 17: 1 by weight, about 16: 1 by weight, about 15:1 by weight, about 14:1 by weight, about 13: 1 by weight, about 12: 1 by weight, about 11: 1 by weight, about 10: 1 by weight, about 9: 1 by weight, about 8: 1 by weight, about 7:1 by weight, about 6:1 by weight, about 5:1 by weight, about 4:1 by weight, about 3: 1 by weight, about 2: 1 by weight, about 1 : 1 by weight.

[0016] In another embodiment, the composition of the pharmaceutical composition comprises unconjugated or naked anti-PSMA antibody and conjugated anti-PSMA antibody chelated to225Ac, wherein the ratio of conjugated anti-PSMA antibody chelated to225Ac to unconjugated or naked anti-PSMA antibody ranges in the ratio of about 40: 1 to about 1:40 by weight, about 30:1 to about 1:30 by weight, about 20: 1 to about 1:20 by weight, about 10:1 to about 1:10 by weight, about 30:1 to about 1: 1 by weight, about 20:1 to about 1: 1 by weight, about 15: 1 to about 1:1 byweight, about 10: 1 to about 1 : 1 by weight, about 1 :30 to about 1 : 1 by weight, about 1 :20 to about 1 : 1 by weight, about 1 : 15 to about 1 : 1 by weight, or about 1 : 10 to about 1 : 1 by weight.

[0017] In another embodiment, the composition or pharmaceutical composition comprises unconjugated or naked J591 and225Ac labeled J591 tetraxetan, wherein the ratio of the unconjugated or naked J591 to225Ac labeled J591 tetraxetan ranges in the ratio of about 40:1 to about 1:40 by weight, about 30: 1 to about 1 :30 by weight, about 20: 1 to about 1 :20 by weight, about 10:1 to about 1 : 10 by weight, about 30: 1 to about 1 : 1 by weight, about 20: 1 to about 1 : 1 by weight, about 15:1 to about 1:1 by weight, about 10:1 to about 1: 1 by weight, about 1:30 to about 1 : 1 by weight, about 1 : 20 to about 1 : 1 by weight, about 1 : 15 to about 1 : 1 by weight, or about 1 :10 to about 1 : 1 by weight.

[0018] In another specific embodiment, the compositions or pharmaceutical compositions may have a specific immunoreactivity or immunoreactive fraction (IRF), thus establishing adequate stability and activity of the pharmaceutical composition. In a specific embodiment, the IRF of225Ac labeled anti-PSMA antibody in the composition or pharmaceutical composition is at least 60%, or at least 70%, or at least 80%, or at least 90%, or at least 91%, or at least 92%, or at least 93%, or at least 94%, or at least 95%, or at least 96%, or at least 97%, or at least 98%, or at least 99%, or about 100%. In another specific embodiment, the immunoreactive fraction (IRF) of a composition or pharmaceutical composition comprising225Ac labeled J591 tetraxetan is at least 60%, or at least 70%, or at least 80%, or at least 90%, or at least 91%, or at least 92%, or at least 93%, or at least 94%, or at least 95%, or at least 96%, or at least 97%, or at least 98%, or at least 99%, or about 100%. In another specific embodiment, the IRF values are determined 10 days or less before administration to a patient. In another specific embodiment, the IRF value is determined by using PSMA-bound magnetic beads. In another specific embodiment, the IRF value is determined as, or substantially similar as, in Example 5, Example 6, or Example 7 described herein. In a specific embodiment, the IRF is determined from the bulk batch as described in Examples 3, 5-7 described herein, or in the sub-batches, which can include the drug product batches for administration directly to a patient. In another embodiment, the IRF is determined from the bulk batch and is used as the reliant IRF measure for determining the sub-batch and final drug product for administration to a patient. In a specific embodiment, the IRF is determined 30 days, 29 days, 28 days, 27 days, 26 days, 25 days, 24 days, 23 days, 22 days, 21 days, 20 days, 19 days, 18 days, 17 days, 16 days, 15 days, 14 days, 13 days, 12 days, 11 days, 10 days, 9 days, 8 days, 7 days, 6days, 5 days, 4 days, 3 days, 2 days, 1 day, or on the day of administration to a patient. In a specific embodiment, this measurement is used as the representative measurement of the final drug product administered to a patient.

[0019] The pharmaceutical compositions described herein may also be administered to a patient or subject in need thereof for the treatment of cancer. In a specific embodiment, the cancer is prostate cancer. In another specific embodiment, the cancer is a PSMA expressing cancer. In another specific embodiment, the cancer is mCRPC. In another specific embodiment, the prostate cancer is castration-sensitive prostate cancer. In another specific embodiment, the methods include administering one or more doses to a patient, wherein the initial dose is a pharmaceutical composition described herein. In another embodiment second or later dose administered to the patient is a pharmaceutical composition described herein. In another specific embodiment, the second dose is administered two to three weeks after the initial dose.

[0020] The present invention also includes methods or processes of conjugating DOTA to an anti- PSMA antibody. In a specific embodiment, the methods include conjugating DOTA to an anti- PSMA antibody by adding a 3 -arm DOTA-NHS to the anti -PSMA antibody at a ratio ranging from about 500: 1 to about 100: 1 DOTA-NHS to the anti -PSMA antibody, or about 400: 1 to about 200: 1 DOTA-NHS to the anti-PSMA antibody, or about 300: 1 DOTA-NHS to the anti-PSMA antibody, wherein the DOTA is covalently linked to the anti-PSMA antibody in an average ratio range of about 5 DOTAs per anti-PSMA antibody to about 3 DOTAs per anti-PSMA antibody. In another specific embodiment, the anti-PSMA antibody comprises: (i) an immunoglobulin heavy chain variable region comprising SEQ ID NO: 1; and (ii) an immunoglobulin light chain variable region comprising SEQ ID NO: 2. In another specific embodiment, at least 90% of the anti-PSMA antibody in the composition is conjugated with about 2-7 or about 3-5 DOTAs.

[0021] The present invention also includes methods or processes of making or chelating225Ac to a DOTA conjugated anti-PSMA antibody. In a specific embodiment, the method of chelating225Ac to a DOTA conjugated anti-PSMA antibody comprises adding225AcCh to a reaction vial comprising 2M tetramethyl ammonium acetate (TMAA) buffer, 0.85 M ascorbic acid. In another specific embodiment, the anti-PSMA antibody comprises: (i) an immunoglobulin heavy chain variable region comprising SEQ ID NO: 1; and (ii) an immunoglobulin light chain variable region comprising SEQ ID NO: 2.BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Fig. 1 shows an HPLC-SEC Fraction Collection of a225Ac labeled J591 tetraxetan composition, which indicates that at least 96% of the J591 antibody is a monomer of225Ac labeled J591 tetraxetan and there are minimal high molecular weight species and low molecular weight species within the tested composition.

[0023] Fig. 2 shows a double reciprocal plot of bead concentration and %Bound and the determination at infinite antigen excess of a composition comprising225Ac labeled J591 tetraxetan.DETAILED DESCRIPTION

[0024] Throughout this disclosure, various patents, patent applications and publications are referenced. The disclosures of these patents, patent applications and publications in their entireties are incorporated into this disclosure by reference for all purposes in order to more fully describe the state of the art as known to those skilled therein as of the date of this disclosure. This disclosure will govern in the instance that there is any inconsistency between the patents, patent applications and publications cited and this disclosure.

[0025] All publications, patents and patent applications, including any drawings and appendices therein are incorporated by reference in their entirety for all purposes to the same extent as if each individual publication, patent or patent application, drawing, or appendix was specifically and individually indicated to be incorporated by reference in While the following terms are believed to be well understood by one of ordinary skill in the art, the following definitions are set forth to facilitate explanation of the presently disclosed subject matter.Definitions

[0026] Throughout the present specification, the terms “about” and / or “approximately” may be used in conjunction with numerical values and / or ranges. The term “about” is understood to mean those values near to a recited value. Furthermore, the phrases “less than about [a value]” or “greaterthan about [a value]” should be understood in view of the definition of the term “about” provided herein. The terms “about” and “approximately” may be used interchangeably.

[0027] Throughout the present specification, numerical ranges are provided for certain quantities. It is to be understood that these ranges comprise all subranges therein. Thus, the range “from 50 to 80” includes all possible ranges therein (e.g., 51-79, 52-78, 53-77, 54-76, 55-75, 60-70, etc.). Furthermore, all values within a given range may be an endpoint for the range encompassed thereby (e.g., the range 50-80 includes the ranges with endpoints such as 55-80, 50-75, etc.).

[0028] The term “a” or “an” refers to one or more of that entity; for example, “a cancer therapeutic” refers to one or more cancer therapeutics or at least one cancer therapeutic. As such, the terms “a” (or “an”), “one or more” and “at least one” are used interchangeably herein. In addition, reference to “an inhibitor” by the indefinite article “a” or “an” does not exclude the possibility that more than one of the inhibitors is present, unless the context clearly requires that there is one and only one of the inhibitors.

[0029] As used herein, the verb “comprise” as is used in this description and in the claims and its conjugations are used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. The present disclosure may suitably “comprise”, “consist of’, or “consist essentially of’, the steps, elements, and / or reagents described in the claims.

[0030] It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as "solely", "only" and the like in connection with the recitation of claim elements, or the use of a "negative" limitation.

[0031] The term “pharmaceutically acceptable salts” includes both acid and base addition salts. Pharmaceutically acceptable salts include those obtained by reacting an active compound functioning as a base, with an inorganic or organic acid to form a salt, for example, salts of hydrochloric acid, sulfuric acid, phosphoric acid, methanesulfonic acid, camphorsulfonic acid, oxalic acid, maleic acid, succinic acid, citric acid, formic acid, hydrobromic acid, benzoic acid, tartaric acid, fumaric acid, salicylic acid, mandelic acid, carbonic acid, etc. Those skilled in the artwill further recognize that acid addition salts may be prepared by reaction of the compounds with the appropriate inorganic or organic acid via any of a number of known methods.

[0032] The term "treating" means one or more of relieving, alleviating, delaying, reducing, improving, or managing at least one symptom of a condition in a subject. The term "treating" may also mean one or more of arresting, delaying the onset (i.e., the period prior to clinical manifestation of the condition) or reducing the risk of developing or worsening a condition.

[0033] The term "therapeutically effective" applied to dose or amount refers to that quantity of an antibody, compound or pharmaceutical formulation that is sufficient to result in a desired clinical benefit after administration to a patient in need thereof.

[0034] As used herein, a “subject” or “patient” can be a human, non- human primate, mammal, rat, mouse, cow, horse, pig, sheep, goat, dog, cat and the like.

[0035] ‘ ‘Mammal” includes humans and both domestic animals such as laboratory animals (e.g., mice, rats, monkeys, dogs, etc.) and household pets (e.g., cats, dogs, swine, cattle, sheep, goats, horses, rabbits), and non-domestic animals such as wildlife and the like.

[0036] All weight percentages (i.e., "% by weight" and "wt. %" and w / w) referenced herein, unless otherwise indicated, are measured relative to the total weight of the pharmaceutical composition.

[0037] As used herein, "substantially" or "substantial" refers to the complete or nearly complete extent or degree of an action, characteristic, property, state, structure, item, or result. For example, an object that is "substantially" enclosed would mean that the object is either completely enclosed or nearly completely enclosed. The exact allowable degree of deviation from absolute completeness may in some cases depend on the specific context. However, generally speaking, the nearness of completion will be so as to have the same overall result as if absolute and total completion were obtained. The use of "substantially" is equally applicable when used in a negative connotation to refer to the complete or near complete lack of action, characteristic, property, state, structure, item, or result. For example, a composition that is "substantially free of' other active agents would either completely lack other active agents, or so nearly completely lack other active agents that the effect would be the same as if it completely lacked other active agents. In otherwords, a composition that is "substantially free of' an ingredient or element or another active agent may still contain such an item as long as there is no measurable effect thereof.

[0038] The terms "pharmaceutical combination," "therapeutic combination" or "combination" as used herein, refers to a single dosage form comprising at least two therapeutically active agents, or separate dosage forms comprising at least two therapeutically active agents together or separately for use in a combination therapy. For example, one therapeutically active agent may be formulated into one dosage form and the other therapeutically active agent may be formulated into a single or different dosage forms. For example, one therapeutically active agent may be formulated into a solid oral dosage form whereas the second therapeutically active agent may be formulated into a solution dosage form for parenteral administration, including as a kit, or from two kits.

[0039] A “fixed dosage form” as used herein means a dosage formulation in which one or more therapeutically active agents are combined in a single dosage formulation.

[0040] A “co-packaged form” as used herein means that the therapeutically active agents are taken together, more than one dosage forms wherein the therapeutically active agents are taken together, or more than one dosage forms wherein the therapeutically active agents are taken separately in two or more pharmaceutical compositions, i.e., such as two or more separate tablets, capsules, gel capsules, pellets, etc, but typically the separate compositions are as a single kit.

[0041] As used herein, the term “pharmaceutical composition” refers to a formulation comprising at least one therapeutically active agent and a pharmaceutically acceptable excipient or carrier. A non-limiting example of pharmaceutical compositions includes tablets, capsules, gel capsules, syrup, liquid, gel, suspension, solid dispersion, or combinations thereof.

[0042] As used herein, “complex” refers to a complex of the compound of the invention, e.g. Formula (I) or Formula (II), complexed with a radionuclide or a metal ion, where at least one metal atom is chelated or sequestered.

[0043] A “conjugate” refers to a chelating agent, complexed or not complexed to at least one metal atom, that is covalently attached to a biological carrier, such as an antibody, including antibody that binds to PSMA.

[0044] As used herein, “PSMA” or “prostate-specific membrane antigen” protein refers to mammalian PSMA, preferably human PSMA protein. The long transcript of PSMA encodes a protein product of about 100-120 kDa molecular weight characterized as a type II transmembrane receptor having sequence homology with the transferrin receptor and having NAALADase activity (Carter et al., “Prostate-Specific Membrane Antigen is a Hydrolase With Substrate and Pharmacologic Characteristics of a Neuropeptidase,” Proc. Natl. Acad. Set. USA 93:749-753 (1996), which is hereby incorporated by reference in its entirety). An anti -PSMA antibody or PSMA receptor antibody is an antibody that interacts with (e.g., binds to) PSMA, preferably human PSMA protein. Preferably, the anti-PSMA antibody or PSMA receptor antibody interacts with, e.g., binds to, the extracellular domain of PSMA, e.g., the extracellular domain of human PSMA located at about amino acids 44-750 of human PSMA (amino acid residues correspond to the human PSMA sequence disclosed in U.S. Pat. No. 5,538,866, which is hereby incorporated by reference in its entirety). Anti-PSMA antibodies or PSMA receptor antibodies are known in the art (Goldsmith et al., “Targeted Radionuclide Therapy for Prostate Cancer,” in Therapeutic Nuclear Medicine 617-628 (R. Baum ed. 2014), which is hereby incorporated by reference in its entirety). Exemplary PSMA receptor antibodies or anti-PSMA antibodies include, but are not limited to, J591, J415, J533, and E99.

[0045] As used herein, the term “biological carrier” refers to any biological targeting vector, such as a protein, an antibody, an antibody fragment, a hormone, a peptide, a growth factor, an antigen, a hapten or any other carrier, which functions in this invention to recognize a specific biological target site. An antibody and an antibody fragment refers to any polyclonal, monoclonal, chimeric, human, mammalian, single chains, dimeric and tetrameric antibody or antibody fragment. Such biological carrier, when attached to a functionalized complex, serves to carry the attached ion to specific targeted tissues.

[0046] As used herein, the term “antibody” refers to a polypeptide that includes canonical immunoglobulin sequence elements sufficient to confer specific binding to a particular target antigen (e.g., a heavy chain variable domain, a light chain variable domain, and / or one or more CDRs sufficient to confer specific binding to a particular target antigen). Thus, the term antibody includes, for example, and without limitation, human antibodies, non-human antibodies, antibody fragments, and antigen-binding agents that include antibody fragments, inclusive of synthetic,engineered, and modified forms thereof. The term antibody includes, by way of example, both naturally occurring and non-naturally occurring antibodies. In general, an antibody may comprise at least two heavy (H) chains and two light (L) chains interconnected by disulfide bonds, or an antigen-binding molecule thereof. Each H chain comprises a heavy chain variable region (abbreviated herein as VH) and a heavy chain constant region. The heavy chain constant region comprises three constant domains, CHI, CH2 and CH3. Each light chain comprises a light chain variable region (abbreviated herein as VL) and a light chain constant region. The light chain constant region comprises one constant domain, CL. The VH and VL regions can be further subdivided into regions of hypervariability, termed complementarity determining regions (CDRs), interspersed with regions that are more conserved, termed framework regions (FR). Each VH and VL comprises three CDRs and four FRs, arranged from amino -terminus to carboxy-terminus in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, and FR4. The variable regions of the heavy and light chains contain a binding domain that interacts with an antigen. The constant regions of the Abs may mediate the binding of the immunoglobulin to host tissues or factors, including various cells of the immune system (e.g., effector cells) and the first component (Clq) of the classical complement system. Naturally-produced antibodies are glycosylated, typically on the CH2 domain. Examples of antibodies include monoclonal antibodies, monospecific antibodies, polyclonal antibodies, multispecific antibodies (including bispecific antibodies), engineered antibodies, recombinantly produced antibodies, wholly synthetic antibodies, humanized antibodies, chimeric antibodies, immunoglobulins, tetrameric antibodies comprising two heavy chain and two light chain molecules, antibody light chain monomers, antibody heavy chain monomers, antibody light chain dimers, antibody heavy chain dimers, antibody light chainantibody heavy chain pairs, intrabodies, antibody fusions (sometimes referred to herein as “antibody conjugates”), heteroconjugate antibodies, single domain antibodies, monovalent antibodies, single chain antibodies or single-chain Fvs (scFv), camelized antibodies, affibodies, Fab fragments, Fab’ fragments, F(ab’)2 fragments, Fd’ fragments, Fd fragments, isolated CDRs, single chain Fvs, polypeptide-Fc fusions, single domain antibodies (e.g., shark single domain antibodies such as IgNAR or fragments thereof); cameloid antibodies; disulfide-linked Fvs (sdFv), anti-idiotypic (anti-Id) antibodies (including, e.g., anti-anti-Id antibodies), minibodies, domain antibodies, synthetic antibodies (sometimes referred to herein as “antibody mimetics”), single chain or Tandem diabodies (TandAb®), Anticalins®, Nanobodies®, minibodies, BiTE®s, ankyrinrepeat proteins or DARPINs®, Avimers®, DARTs, TCR-like antibodies, Adnectins®, Affilins®, Trans-bodies®, Affibodies®, TrimerX®, MicroProteins, m Fynomers®, Centyrins®, KALBITOR®s, and antigen-binding fragments of any of the above.

[0047] As used herein, the term “Fc-silent antibody” refers to an antibody comprising one or more mutations in the Fc domain that reduce, prevent, or eliminate binding of the Fc region of the antibody to Fc receptors, such as FcyR or FcR, which may result in decreased antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and / or complement-dependent cytotoxicity (CDC). Exemplary mutations that may reduce, prevent, or eliminate antibody binding to an Fc receptor include, but are not limited to, S228P, E233P, L234A, L235A, L235E, L235F, G236R, G237A, D265A, N297A, L328R, P331S, and any combination thereof (Saunders, Conceptual Approaches to Modulate Antibody Effector Functions and Circulation Half-Life, Front. Immunol., 2019, doi.org / 10.3389 / fimmu.2019.01296). In some embodiments, substitution of any or all of positions 234, 235, 236 and / or 237 reduces affinity for Fey receptors, particularly FcyRl receptor (see, e.g., U.S. Pat. No. 6,624,821). In some embodiments, alanine is a preferred residue for substitution and L234A / L235A is a preferred dual mutation to reduce effector function. In some embodiments, other combinations of mutations with reduced effector functions include, but are not limited to, L234A / L235A / G237A, E233P / L234V / L235A / G236, A327G / A330S / P331S, K322A, L234A and L235A,L234F / L235E / P331S. Optionally, positions 234, 236 and / or 237 in human IgG2 are substituted with alanine and position 235 with glutamine, (see, e.g., U.S. Pat. No. 5,624,821). Two amino acid substitutions in the complement Clq binding site at EU index positions 330 and 331 reduce complement fixation (see Tao et al., J. Exp. Med. 178:661 (1993) and Canfield and Morrison, J. Exp. Med. 173: 1483 (1991)). Substitution into human IgGl of IgG2 residues at positions 233-236 and IgG4 residues at positions 327, 330 and 331 greatly reduces ADCC and CDC (see, for example, Armour K L. et ah, 1999 Eur J Immunol. 29(8):2613-24; and Shields RL. et ah, 2001. J Biol Chem. 276(9): 6591-604). N297A, N297Q, or N297G (Eu numbering) mutations reduce glycosylation and thereby effector functions. In some embodiments, any of the antibodies disclosed herein comprise one or more mutations in the Fc region to reduce, prevent, or eliminate binding to Fc receptors. In some embodiments, any of the antibodies disclosed herein comprise one or more mutations in the Fc region to reduce, prevent, or eliminate binding to FcyR. In some embodiments, any of the antibodies disclosed herein comprise one or more mutations in the Fcregion to reduce, prevent, or eliminate binding to FcyRIIIA. In some embodiments, any of the antibodies disclosed herein comprise one or more mutations in the Fc region to reduce, prevent, or eliminate binding to FcyRFV. In some embodiments, any of the antibodies disclosed herein comprise one or more mutations in the Fc region to reduce, eliminate or prevent ADCC, ADCP, and / or CDC. In some embodiments, mutations in the Fc region to reduce, prevent, or eliminate binding to Fc receptors occur at EU index positions 228, 233, 234, 235, 235, 235, 236, 237, 265, 297, 322, 327, 328, 330, 331, and any combination thereof. In some embodiments, mutations in the Fc region to reduce, prevent, or eliminate binding to Fc receptors include, but are not limited to, S228P, E233P, L234A, L235A, L235E, L235F, G236R, G237A, D265A, N297A, K322A, A327G, L328R, A330S, P331S, and any combination thereof. Additional mutations in the Fc region that reduce, prevent, or eliminate binding to Fc receptors and alternative strategies for reducing, preventing, or eliminating binding to Fc receptors are described in, e.g., Saunders, 2019, Tao, 1993, Canfield and Morrison, 1991, Armour, 1999, Shields, 2001, and U.S. No. 6,624,821.

[0048] As used herein, the terms “Fc-enabled antibody,” “Fc-enhanced antibody,” and “Fc- competent antibody” are used interchangeably and refer to an antibody comprising an FC domain that is capable of binding to Fc receptors, such as FcyR or FcR. These antibodies may further comprise one or more mutations to enhance or increase binding to Fc receptors, which may result in enhanced antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and / or complement-dependent cytotoxicity (CDC). Exemplary mutations that may enhance ADCC include, but are not limited to, S298A, E333A, K334A, S239D, I332E, P247I, A339Q, and any combination thereof (van der Horst, et al., Fc-Engineered Antibodies with Enhanced Fc-Effector Function for the Treatment of B-Cell Malignancies, Cancers (Basel), 12(10):3041, 2020). Exemplary mutations that may enhance ADCP include, but are not limited to, F234L, R292P, Y300L, V305I, P396L, A330L, G236A, and any combination thereof (van der Horst, et al., 2020). Exemplary mutations that may enhance CDC include, but are not limited to, E345G, E430G, K326W, E333S, S267E, H268E, S324T, and any combination thereof (van der Horst, et al., 2020). In some embodiments, any of the antibodies disclosed herein comprise one or more mutations in the Fc region to enhance or enable binding to Fc receptors. In some embodiments, any of the antibodies disclosed herein comprise one or more mutations in the Fc region to enhance or enable binding to FcyR. In some embodiments, any of the antibodies disclosed herein comprise one or more mutations in the Fc region to enhance or enable binding to FcyRIIIA.In some embodiments, any of the antibodies disclosed herein comprise one or more mutations in the Fc region to enhance or enable binding to FcyRIV. In some embodiments, any of the antibodies disclosed herein comprise one or more mutations in the Fc region to enable or enhance ADCC, ADCP, and / or CDC. In some embodiments, one or more substitutions in the Fc region to enhance or enable binding to Fc receptors occur at EU index positions 234, 235, 236, 239, 243, 247, 267, 268, 292, 298, 300, 305, 324, 326, 330, 332, 333, 334, 339, 345, 396, 430, and any combination thereof. In some embodiments, mutations in the Fc region to enhance or enable binding to Fc receptors include, but are not limited to, F234L, L235V, G236A, S239D, F243L, P247I, S267E, H268E, R292P, S298A, Y300L, V305I, S324T, K326W, A330L, I332E, E333A, E333S, K334A, A339Q, E345G, P396L, E430G, and any combination thereof. In some embodiments, the Fc- enabled antibody comprises a modified IgGI domain characterized by substitutions at S239D, A330L, and I332E (Eu numbering). Alternatively, glycoform perturbation can be used to enhance Fc-mediated therapeutic antibody function. The N-linked Fc glycosylations on IgGI antibodies are important for effector function. Sialylation, galactosylation, bisecting sugars, and fucosylation can all affect binding and activity of IgG molecules. Controlling the glycosylation patterns on therapeutic antibodies can be done a number of different ways. The type of cell producing the recombinant antibody and its culture conditions can affect glycosylation and activity of therapeutic antibodies. Furthermore, bioreactor conditions and downstream processing can also affect the glycan microheterogenity. Low or afucosylated antibodies have been shown to enhance remediating properties. Numerous ways to achieve this reduction of fucose levels by glycoengineering are well known in the art. One way is to manipulate the enzymes involved in the post-translational modification of antibodies. This can involve overexpression of glucosidases, such as P-l-4-N-acetylglucosaminyltransferase III, knocking out fucoslytransferases, or using cell lines that are naturally fucose-deficient or have been mutated to express low fucosylation levels. In addition, inhibitors of N-linked glucosidases, such as castanospermine, can also be used to obtain low fucose bearing IgG molecules. In some embodiments amino acid engineered variants can have more broadly enhanced affinity for multiple FcyR, whereas glycoform engineered antibody can generally have more specific affinity for enhanced FcyRIIIa binding. Glycoforms interact with proximal amino acids on the Fc portion and replacement of the amino acid that come in contact with Ig oligosaccharides can result in different glycoform structures. Additionalmutations in the Fc region that enhance or enable binding to Fc receptors and alternative strategies for enhancing or enabling binding to Fc receptors are described in Saunders, 2019.

[0049] As used herein, the terms “chelator” or “chelating agent” refers to a chemical compound to which a radiometal, such as actinium-225, or metal can be chelated via coordinate bonding. Preferably, the chelator comprises a heterocyclic ring such as DOTA.

[0050] As used herein, the terms “chelant” or “chelate” are interchangeable and refers to the chelator or chelating agent bonded to the radiometal or metal.

[0051] As used herein, the term “complex” refers to a chelant-linker-biomolecule configuration, for example, actinium-225-chelator-antibody, or more specifically an actinium-225-DOTA conjugated antibody.

[0052] As used herein, the term “bulk batch” refers to a batch, which can be in any form, such as solid or solution, comprising more than one dose of a drug, such as J591, for a patient. In a specific example, the bulk batch comprises multiple doses of a drug in a solution, wherein smaller individual doses are withdrawn from the bulk batch into sub-batches for further processing and / or administration to a patient.

[0053] As used herein, the term “sub-batch” includes any portion of a dose withdrawn from a bulk batch. The sub-batch can be further processed and / or directly administered to a patient. For example, a sub-batch can be a portion taken from the bulk batch, and additional drug and / or pharmaceutical acceptable excipients may be added to that sub-batch. In another example, the sub-batch may comprise a unit dose of the drug, such as actinium-225-chelator-antibody.Compositions of the Present Disclosure

[0054] The present disclosure relates to compositions, including pharmaceutical compositions, comprising anti-PSMA antibody or an anti-PSMA antibody fragment conjugated to a chelator. In a specific embodiment, the chelator is a l,4,7,10-tetraazacyclododecane-l,4,7,10-tetraacetic acid (DOTA) chelator. In another embodiment, the DOTA is conjugated in a 3 arm or 4 arm configuration with the anti-PSMA antibody or anti-PSMA antibody fragment.

[0055] In another embodiment, the anti-PSMA antibody is J591. In a specific embodiment, J591 is as described in U.S. Patent No. 7,045,605, and PCT application publication WO2018 / 204477, which are hereby incorporated by reference in its entirety.

[0056] In one embodiment, the anti-PSMA antibody is selected from the group consisting of J591, J415, J533, and E99.

[0057] In another embodiment, the anti-PSMA antibody or anti-PSMA antibody fragment comprises: (i) an immunoglobulin heavy chain variable region comprising SEQ ID NO: 1; and / or (ii) an immunoglobulin light chain variable region comprising SEQ ID NO: 2, as shown in Table 1.

[0058] TABLE I:

[0059] In another embodiment, the chelator is one of the chelators in Table 2.

[0060] TABLE 2:

[0061] In another specific embodiment, the chelator is DOTA, H2-MACROPA or PCTA. In another specific embodiment, the chelator is DOTA, which may be to form a three arm or four arm DOTA to an anti-PSMA antibody.

[0062] In another specific embodiment, the chelator is DOTA conjugated to an anti-PSMA antibody, such as an anti-PSMA monoclonal antibody. In another specific embodiment, the anti- PSMA monoclonal antibody is J591.

[0063] In another embodiment, the radionuclide is225Ac and the chelator is DOTA, H2- MACROPA or PCTA. In another specific embodiment, the chelator is DOTA, which may be 3 arm or 4 arm DOTA.

[0064] In specific embodiments, the conjugate is of Formula I:wherein mAb is an anti-PSMA monoclonal antibody and L is a linker e.g., as disclosed herein.

[0065] In another specific embodiment, the conjugate is of Formula IIwherein mAb is an anti-PSMA monoclonal antibody.

[0066] In one embodiment, the chelator and antibody are linked with methods known in the art, including for example the use of NHS-ester or isothiocyanate linkage systems. In a specific embodiment, the linker conjugate binds to any amino acid of the antibody. In a specific embodiment, the conjugate is bound to a nucleophilic amino acid on the antibody. In a specific embodiment, the amino acid is at least a lysine.

[0067] In one embodiment, the linker L is used to link the chelator and antibody with methods known in the art, including for example the use of NHS-ester or isothiocyanate linkage systems. In one embodiment, the linker L comprises -N-C(=S)- or -C(=O)-. In another specific embodiment, L is: Co-2oalkylene-C(=0)- or Co-2oalkylene-(Cyc)0-N-C(=S)-, wherein Cyc is a carbocyclic or heterocyclic ring, each of said moieties optionally substituted with one or more groups which do not interfere with binding to the antibody; and o is 0 or 1. In another embodiment, L is:

[0069] In another embodiment, the compositions or pharmaceutical compositions of the present application comprise various ratios of anti-PSMA antibody or an anti-PSMA antibody fragment to chelator from the conjugation process. In a specific embodiment, the anti-PSMA antibody or an anti-PSMA antibody fragment is conjugated to a chelator wherein the chelator is covalently linked to the anti-PSMA antibody in an average ratio range of about 1 chelator per anti-PSMA antibody or anti-PSMA antibody fragment to about 10 chelators per anti-PSMA antibody or anti-PSMA antibody fragment. In another embodiment, the anti-PSMA antibody or an anti-PSMA antibody fragment is conjugated to a chelator wherein the chelator is covalently linked to the anti-PSMA antibody in an average ratio range of about 2 chelators per anti-PSMA antibody or anti-PSMA antibody fragment to about 10 chelators per anti-PSMA antibody or anti-PSMA antibody fragment. In another embodiment, the anti-PSMA antibody or anti-PSMA antibody fragment isconjugated to a chelator wherein the chelator is covalently linked to the anti-PSMA antibody in an average ratio range of about 2 chelators per anti-PSMA antibody or anti-PSMA antibody fragment to about 9 chelators per anti-PSMA antibody or anti-PSMA antibody fragment. In another embodiment, the anti-PSMA antibody or anti-PSMA antibody fragment is conjugated to a chelator wherein the chelator is covalently linked to the anti-PSMA antibody in an average ratio range of about 2 chelators per anti-PSMA antibody or anti-PSMA antibody fragment to about 8 chelators per anti-PSMA antibody or anti-PSMA antibody fragment. In another embodiment, the anti- PSMA antibody or anti-PSMA antibody fragment is conjugated to a chelator wherein the chelator is covalently linked to the anti-PSMA antibody in an average ratio range of about 3 chelators per anti-PSMA antibody or anti-PSMA antibody fragment to about 7 chelators per anti-PSMA antibody or anti-PSMA antibody fragment. In another embodiment, the anti-PSMA antibody or anti-PSMA antibody fragment is conjugated to a chelator wherein the chelator is covalently linked to the anti-PSMA antibody in an average ratio range of about 3 chelators per anti-PSMA antibody or anti-PSMA antibody fragment to about 5 chelators per anti-PSMA antibody or anti-PSMA antibody fragment. In another embodiment, the anti-PSMA antibody is J591. In another embodiment, the chelator is DOTA. In another specific embodiment, the conjugate may be included in a pharmaceutical composition additionally comprising a pharmaceutically acceptable carrier or excipient.

[0070] In another embodiment, the conjugated anti-PSMA antibody or anti-PSMA antibody fragment is chelated or complexed to a radionuclide. In a specific embodiment, the radionuclide is225Ac. In another embodiment, the composition or pharmaceutical composition is substantially free of unchelated, or free,225Ac. In another embodiment, the composition or pharmaceutical composition contains less than about 10% of unchelated, or free,225Ac. In another embodiment, the composition or pharmaceutical composition contains less than about 9% of unchelated, or free,225Ac. In another embodiment, the composition or pharmaceutical composition contains less than about 8% of unchelated, or free,225Ac. In another embodiment, the composition or pharmaceutical composition contains less than about 7% of unchelated, or free,225Ac. In another embodiment, the composition or pharmaceutical composition contains less than about 6% of unchelated, or free,225Ac. In another embodiment, the composition or pharmaceutical composition contains less than about 5% of unchelated, or free,225Ac. In another embodiment, the composition or pharmaceutical composition contains less than about 4% of unchelated, or free,225Ac. In another embodiment, thecomposition or pharmaceutical composition contains less than about 3% of unchelated, or free,225Ac. In another embodiment, the composition or pharmaceutical composition contains less than about 2% of unchelated, or free,225Ac. In another embodiment, the composition or pharmaceutical composition contains less than about 1% of unchelated, or free,225Ac.

[0071] In another embodiment, a substantial amount or majority of the225Ac activity in the composition or pharmaceutical composition is complexed or bound to conjugated anti-PSMA antibody such as a J591-DOTA conjugate. In a specific embodiment, at least about 80% of the225Ac activity in the composition or pharmaceutical composition is complexed or bound to conjugated anti-PSMA antibody. In another embodiment, at least about 90% of the225Ac activity in the composition or pharmaceutical composition is complexed or bound to conjugated anti- PSMA antibody. In another embodiment, at least about 91% of the225Ac activity in the composition or pharmaceutical composition is complexed or bound to conjugated anti-PSMA antibody. In another embodiment, at least about 92% of the225Ac activity in the composition or pharmaceutical composition is complexed or bound to conjugated anti-PSMA antibody. In another embodiment, at least about 93% of the225Ac activity in the composition or pharmaceutical composition is complexed or bound to conjugated anti-PSMA antibody. In another embodiment, at least about 94% of the225Ac activity in the composition or pharmaceutical composition is complexed or bound to conjugated anti-PSMA antibody. In another embodiment, at least about 95% of the225Ac activity in the composition or pharmaceutical composition is complexed or bound to conjugated anti-PSMA antibody. In another embodiment, at least about 96% of the225Ac activity in the composition or pharmaceutical composition is complexed or bound to conjugated anti-PSMA antibody. In another embodiment, at least about 97% of the225Ac activity in the composition or pharmaceutical composition is complexed or bound to conjugated anti-PSMA antibody. In another embodiment, at least about 98% of the225Ac activity in the composition or pharmaceutical composition is complexed or bound to conjugated anti-PSMA antibody. In another embodiment, at least about 99% of the225Ac activity in the composition or pharmaceutical composition is complexed or bound to conjugated anti-PSMA antibody. In another embodiment, the determination of the unchelated or free225Ac or the percentage of225Ac activity bound or complexed to the conjugated anti-PSMA antibody in the composition or pharmaceutical composition is determined by methods known in the art such as by HPLC-SEC. In another specificembodiment, the anti-PSMA antibody is J591. In another embodiment, J591 is conjugated to DOTA and chelated or complexed to225Ac, also known as225Ac labeled J591 tetraxetan.

[0072] In another embodiment, the composition or pharmaceutical composition comprising225Ac activity complexed or bound to conjugated anti-PSMA antibody can be further purified. In one example, postradiolabeling purification can be applied with techniques known in the art, for example, using column chromatography purification such as with a protein A column, HIC column, size exclusion column, an ion exchange column, columns to specifically bind to a tag on the antibody (ex, His-tag), and other known affinity chromatography techniques.

[0073] In another embodiment, the composition may be a bulk composition or a composition comprising more than one dose to a patient. In one embodiment, the composition may comprise at least 2 doses, at least 3 doses, at least 4 doses, at least 5 doses, at least 6 doses, at least 7 doses, at least 8 doses, at least 9 doses at least 10 doses, at least 11 doses, at least 12 doses, at least 13 doses, at least 14 doses, at least 15 doses, at least 16 doses, at least 17 doses, at least 18 doses, at least 19 doses, or at least 20 doses for one or more patients. In another specific embodiment, the bulk composition comprises 2 doses, 3 doses, 4 doses, 5 doses, 6 doses, 7 doses, 8 doses, 9 doses 10 doses, 11 doses, 12 doses, 13 doses, 14 doses, 15 doses, 16 doses, 17 doses, 18 doses, 19 doses, or 20 doses for one or more patients.

[0074] In another specific embodiment, the composition comprises a total of about 0. 1 mCi to about 3.0 mCi from225Ac. In another embodiment, the composition comprises a total of about 0.25 mCi to about 2.5 mCi from225Ac. In another embodiment, the composition comprises a total of about 0.5 mCi to about 2.0 mCi from225Ac. In another embodiment, the composition comprises a total of about 0.25 mCi to about 2.5 mCi from225Ac. In another embodiment, the composition comprises a total of about 0.5 mCi to about 1.5 mCi from225Ac. In another embodiment, the composition comprises a total of about 0.5 mCi to about 1.0 mCi from225Ac.

[0075] In another specific embodiment, the composition comprises a total of about 0. 1 mCi to about 5.0 mCi from225Ac. In another embodiment, the composition comprises a total of about 0.25 mCi to about 3.5 mCi from225Ac. In another embodiment, the composition comprises a total of about 0.5 mCi to about 2.5 mCi from225Ac. In another embodiment, the composition comprises a total of about 0.25 mCi to about 2.5 mCi from225Ac. In another embodiment, the compositioncomprises a total of about 0.5 mCi to about 2 mCi from225Ac. In another embodiment, the composition comprises a total of about 0.5 mCi to about 1.5 mCi from225Ac. In another embodiment, the composition comprises a total of about 0.5 mCi to about 1.0 mCi from225Ac.

[0076] In another specific embodiment, the compositions of the present invention include pharmaceutical compositions and non-pharmaceutical compositions comprising an anti-PSMA antibody or an anti-PSMA antibody fragment conjugated to a chelator, wherein the conjugated anti-PSMA antibody or anti-PSMA antibody fragment are substantially in the form of a monomer. In another specific embodiment, the pharmaceutical compositions or non-pharmaceutical compositions of the present invention comprise225Ac labeled anti-PSMA antibody conjugate substantially in the form of a monomer. In another specific embodiment, at least about 60%, or at least about 70%, or at least about 80% of the225Ac labeled anti-PSMA antibody conjugate in the composition is in the form of a monomer. In another specific embodiment, at least about 85% of the225Ac labeled anti-PSMA antibody conjugate is in the composition in the form of a monomer. In another specific embodiment, at least about 90% of the225Ac labeled anti-PSMA antibody conjugate is in the composition in the form of a monomer. In another specific embodiment, at least about 91% of the225Ac labeled anti-PSMA antibody conjugate in the composition is in the form of a monomer. In another specific embodiment, at least about 92% of the225Ac labeled anti-PSMA antibody conjugate in the composition is in the form of a monomer. In another specific embodiment, at least about 93% of the225Ac labeled anti-PSMA antibody conjugate in the composition is in the form of a monomer. In another specific embodiment, at least about 94% of the225Ac labeled anti-PSMA antibody conjugate in the composition is in the form of a monomer. In another specific embodiment, at least about 95% of the225Ac labeled anti-PSMA antibody conjugate in the composition is in the form of a monomer. In another specific embodiment, at least about 96% of the225Ac labeled anti-PSMA antibody conjugate in the composition is in the form of a monomer. In another specific embodiment, at least about 97% of the225Ac labeled anti-PSMA antibody conjugate is in the composition in the form of a monomer. In another specific embodiment, at least about 98% of the225Ac labeled anti-PSMA antibody conjugate in the composition is in the form of a monomer. In another specific embodiment, at least about 99% of the225Ac labeled anti-PSMA antibody conjugate in the composition is in the form of a monomer. In another specific embodiment, the anti-PSMA antibody conjugate is conjugated to DOTA. In another specific embodiment, the anti-PSMA antibody is J591. In another specific embodiment,at least about 60%, or about 70%, or about 80%, or about 90% of the225Ac labeled J591 tetraxetan in the composition is in the form of a monomer. In another specific embodiment, at least about 91% of the225AC labeled J591 tetraxetan is in the composition in the form of a monomer. In another specific embodiment, at least about 92% of225Ac labeled J591 tetraxetan is in the composition in the form of a monomer. In another specific embodiment, at least about 93% of the225Ac labeled J591 tetraxetan in the composition is in the form of a monomer. In another specific embodiment, at least about 94% of the225Ac labeled J591 tetraxetan in the composition is in the form of a monomer. In another specific embodiment, at least about 95% of the225Ac labeled J591 tetraxetan in the composition is in the form of a monomer. In another specific embodiment, at least about 96% of the225Ac labeled J591 tetraxetan in the composition is in the form of a monomer. In another specific embodiment, at least about 97% of225Ac labeled J591 tetraxetan in the composition is in the form of a monomer. In another specific embodiment, at least about 98% of the225Ac labeled J591 tetraxetan in the composition is in the form of a monomer. In another specific embodiment, at least about 99% of the225Ac labeled J591 tetraxetan in the composition is in the form of a monomer.

[0077] In another embodiment, the composition or pharmaceutical composition, including the bulk composition or the single unit dose composition, may have a particular immunoreactivity. The conjugation of chelating agents to an antibody as well as labeling procedure or radiolysis during mAb storage may adversely alter the antibody and affect the immunoreactivity. Unfavorable in vivo behavior of radioimmunopharmaceuticals, such as reduced tumor uptake, increased nonspecific localization and radiation exposure of nontarget tissues, can be result. Therefore, the determination of immunoreactive fraction (IRF) is essential to ensure the efficacy and stability of radiolabeled antibodies, including the drug product. In a specific embodiment, the immunoreactivity or IRF of225Ac labeled anti-PSMA antibody conjugate (such as225AC labeled J591 tetraxetan) is tested as described in J. Immunol. Methods 1984, 72 (1), 77- 89. In another embodiment, the immunoreactivity or IRF of225Ac labeled anti-PSMA antibody conjugate (such as225Ac labeled J591 tetraxetan) is tested as described in Nucl Med Biol. 2019 Apr; 71: 32-38 by using PSMA-bound magnetic beads. In a specific embodiment, the composition or pharmaceutical composition comprises225Ac labeled anti-PSMA antibody conjugate (such as225Ac labeled J591 tetraxetan), wherein the immunoreactive fraction (IRF) of225Ac labeled anti-PSMA antibody conjugate (such as225Aclabeled J591 tetraxetan) is at least 60%, or at least 65%, or at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95%. In another embodiment, the IRF is determined using PSMA-bound magnetic beads. In another specific embodiment, the IRF is determined as in m ' Nucl Med Biol. 2019 Apr; 71: 32-38.

[0078] In another specific embodiment, the immunoreactive fraction (IRF) of a composition or pharmaceutical composition comprising225Ac labeled J591 tetraxetan is at least 60%, or at least 70%, or at least 80%, or at least 90%, or at least 91%, or at least 92%, or at least 93%, or at least 94%, or at least 95%, or at least 96%, or at least 97%, or at least 98%, or at least 99%, or about 100%. In another specific embodiment, the IRF values are determined 7 days or less before administration to a patient. In another specific embodiment, the IRF value is determined by using PSMA-bound magnetic beads. In another specific embodiment, the IRF value is determined as or substantially similar as in Example 5 or Example 6.

[0079] In another specific embodiment, the compositions or pharmaceutical compositions may have a specific immunoreactivity or immunoreactive fraction (IRF), thus establishing adequate stability and activity of the pharmaceutical composition. In a specific embodiment, the IRF of225Ac labeled anti-PSMA antibody in the composition or pharmaceutical composition is at least 60%, or at least 70%, or at least 80%, or at least 90%, or at least 91%, or at least 92%, or at least 93%, or at least 94%, or at least 95%, or at least 96%, or at least 97%, or at least 98%, or at least 99%, or about 100%. In another specific embodiment, the immunoreactive fraction (IRF) of a composition or pharmaceutical composition comprising225Ac labeled J591 tetraxetan is at least 60%, or at least 70%, or at least 80%, or at least 90%, or at least 91%, or at least 92%, or at least 93%, or at least 94%, or at least 95%, or at least 96%, or at least 97%, or at least 98%, or at least 99%, or about 100%. In another specific embodiment, the IRF values are determined 10 days or less before administration to a patient. In another specific embodiment, the IRF value is determined by using PSMA-bound magnetic beads. In another specific embodiment, the IRF value is determined as, or substantially similar as, in Example 5, Example 6, or Example 7 described herein. In a specific embodiment, the IRF is determined on the bulk batch as described in Examples 3, 5- 7 described herein. In another embodiment, the IRF determined on the bulk batch and is used as the reliant IRF measure for determining the sub-batch and final drug product for administration to a patient. In a specific embodiment, the IRF is determined, 30 days, 29 days, 28 days, 27 days, 26days, 25 days, 24 days, 23 days, 22 days, 21 days, 20 days, 19 days, 18 days, 17 days, 16 days, 15 days, 14 days, 13 days, 12 days, 11 days, 10 days, 9 days, 8 days, 7 days, 6 days, 5 days, 4 days, 3 days, 2 days, 1 day, or on the day of administration to a patient. In a specific embodiment, this measurement is used as the representative measurement of the final drug product administered to a patient.

[0080] Single unit Dose Formulations

[0081] In another embodiment, the composition may be a single dose composition or a single unit dose. In a specific embodiment, the composition is a pharmaceutical composition for a single administration to a subject. In a specific embodiment, the single dose is for injection to a patient and may be supplied or stored in a vial. In one embodiment, the composition may comprise one or more pharmaceutically acceptable carriers or excipients.

[0082] In another specific embodiment, the pharmaceutical composition comprises a225Ac labeled anti-PSMA antibody conjugate, such as225Ac labeled J591 tetraxetan and a pharmaceutically acceptable excipient or carrier, wherein the composition comprises a specific radioactivity per mg of antibody or antibody fragment. In a specific embodiment, the pharmaceutical composition comprises about 1 pCi to about 100 pCi per mg of anti-PSMA antibody. In a specific embodiment, the pharmaceutical composition comprises about 2 pCi to about 75 pCi per mg of anti-PSMA antibody. In a specific embodiment, the pharmaceutical composition comprises about 2.25 pCi to about 50 pCi per mg of anti-PSMA antibody. In a specific embodiment, the pharmaceutical composition comprises about 2.5 pCi to about 20 pCi per mg of anti-PSMA antibody. In a specific embodiment, the pharmaceutical composition comprises about 3 pCi to about 15 pCi per mg of anti-PSMA antibody. In another embodiment, the amount of anti-PSMA antibody in a single unit dose is about 5 mg to about 50 mg. In another specific embodiment, the amount of anti-PSMA antibody in a single unit dose is about 10 mg to about 30 mg. In another specific embodiment, the amount of anti-PSMA antibody in a single unit dose is about 15 mg to about 25 mg. In another specific embodiment, the amount of anti-PSMA antibody in a single unit dose is about 20 mg. In another specific embodiment, the amount of anti- PSMA antibody in a single unit dose is about 21 mg, about 22 mg, about 23 mg, about 24 mg, or about 25 mg.

[0083] In another embodiment, the composition of a single unit dose comprises a total of about 1 pCi to 1000 pCi of225Ac per 20 mg of anti-PSMA antibody. In another embodiment, the composition of a single unit dose comprises a total of about 10 pCi to 500 pCi of225Ac per 20 mg of anti-PSMA antibody. In another embodiment, the composition of a single unit dose comprises a total of about 25 pCi to 400 pCi of225Ac per 20 mg of anti-PSMA antibody. In another embodiment, the composition of a single unit dose comprises a total of about 30 pCi to 350 pCi of225Ac per 20 mg of anti-PSMA antibody. In another embodiment, the composition of a single unit dose comprises a total of about 50 pCi to 250 pCi of225Ac per 20 mg of anti-PSMA antibody. In another embodiment, the composition of a single unit dose comprises a total of aboutlOO pCi to 200 pCi of225Ac per 20 mg of anti-PSMA antibody.

[0084] In another embodiment, the composition of a single unit dose comprises a total volume capable for a single injection in a patient or subject. In a specific embodiment, the composition of a single unit dose comprises a total volume of about 5 ml to about 50 ml, or about 10 ml to about 40 ml, or about 15 to about 30 ml, or about 17 ml to about 25 ml, or about 20 ml. In another embodiment, the amount of anti-PSMA antibody in a single unit dose is about 5 mg to about 50 mg per 20 ml volume. In another specific embodiment, the amount of anti-PSMA antibody in a single unit dose is about 10 mg to about 30 mg per 20 ml volume. In another specific embodiment, the amount of anti-PSMA antibody in a single unit dose is about 15 mg to about 25 mg per 20 ml volume. In another specific embodiment, the amount of anti-PSMA antibody in a single unit dose is about 20 mg per 20 ml volume.

[0085] In another embodiment, the composition of a single unit dose comprises a total of about 1 pCi to 1000 pCi of225AC per 20 mg of anti-PSMA antibody per 20 ml volume. In another embodiment, the composition of a single unit dose comprises a total of about 10 pCi to 500 pCi of225AC per 20 mg of anti-PSMA antibody per 20 ml volume. In another embodiment, the composition of a single unit dose comprises a total of about 25 pCi to 400 pCi of225Ac per 20 mg of anti-PSMA antibody per 20 ml volume. In another embodiment, the composition of a single unit dose comprises a total of about 30 pCi to 350 pCi of225Ac per 20 mg of anti-PSMA antibody per 20 ml volume. In another embodiment, the composition of a single unit dose comprises a total of about 50 pCi to 250 pCi of225Ac per 20 mg of anti-PSMA antibody per 20 ml volume. Inanother embodiment, the composition of a single unit dose comprises a total of about 100 pCi to 200 pCi of225Ac per 20 mg of anti-PSMA antibody per 20 ml volume.

[0086] In another specific embodiment, the composition and dose may be determined and vary based on the weight of the patient or subject. In a specific embodiment, the composition comprises a single dose ranging from about 10 KBq / kg weight of a patient to about 150 KBq / kg weight of a patient. In a specific embodiment, the composition comprises a single dose ranging from about 15 KBq / kg weight of a patient to about 100 KBq / kg weight of a patient. In a specific embodiment, the composition comprises a single dose ranging from about 25 KBq / kg weight of a patient to about 65 KBq / kg weight of a patient.

[0087] In another specific embodiment, the composition additionally comprises unconjugated (or naked) anti-PSMA antibody. In another embodiment, the unconjugated (or naked) anti-PSMA antibody has the same amino acid sequence as the conjugated anti-PSMA antibody or antibody fragment. In another specific embodiment, the anti-PSMA antibody is J591. In another embodiment, the anti-PSMA antibody or anti-PSMA antibody fragment comprises: (i) an immunoglobulin heavy chain variable region comprising SEQ ID NO: 1; and (ii) an immunoglobulin light chain variable region comprising SEQ ID NO: 2.

[0088] In another embodiment, the total anti-PSMA, antibody, i.e., the total of the conjugated and unconjugated antibody is at a concentration of about 0.1 mg / ml to about 5 mg / ml in the composition. In another embodiment, the total anti-PSMA antibody is at a concentration of about 0.2 mg / ml to about 3 mg / ml in the composition. In another embodiment, the total anti-PSMA antibody is at a concentration of about 0.4 mg / ml to about 2 mg / ml in the composition. In another embodiment, the total anti-PSMA antibody is at a concentration of about 0.6 mg / ml to about 1.5 mg / ml in the composition. In another embodiment, the total anti-PSMA antibody is at a concentration of about 0.7 mg / ml to about 1.2 mg / ml in the composition.

[0089] Pharmaceutical compositions of the present invention may be single unit dose compositions or intended for a single dose administered to a subject and comprise225Ac labeled anti-PSMA antibody conjugate substantially in the form of a monomer. In another specific embodiment, at least about 80% of the225Ac labeled anti-PSMA antibody conjugate in the composition is in the form of a monomer. In another specific embodiment, at least about 85% ofthe225Ac labeled anti-PSMA antibody conjugate in the composition is in the form of a monomer. In another specific embodiment, at least about 90% of the225Ac labeled anti-PSMA antibody conjugate in the composition is in the form of a monomer. In another specific embodiment, at least about 91% of the225Ac labeled anti-PSMA antibody conjugate in the composition is in the form of a monomer. In another specific embodiment, at least about 92% of the225Ac labeled anti-PSMA antibody conjugate in the composition is in the form of a monomer. In another specific embodiment, at least about 93% of the225Ac labeled anti-PSMA antibody conjugate in the composition is in the form of a monomer. In another specific embodiment, at least about 94% of the225Ac labeled anti-PSMA antibody conjugate in the composition is in the form of a monomer. In another specific embodiment, at least about 95% of the225Ac labeled anti-PSMA antibody conjugate in the composition is in the form of a monomer. In another specific embodiment, at least about 96% of the225Ac labeled anti-PSMA antibody conjugate in the composition is in the form of a monomer. In another specific embodiment, at least about 97% of the225Ac labeled anti-PSMA antibody conjugate in the composition is in the form of a monomer. In another specific embodiment at least about 98% of the225Ac labeled anti-PSMA antibody conjugate in the composition is in the form of a monomer. In another specific embodiment, at least about 99% of the225Ac labeled anti-PSMA antibody conjugate in the composition is in the form of a monomer. In another specific embodiment, the anti-PSMA antibody conjugate is conjugated to DOTA. In another specific embodiment, the anti-PSMA antibody is J591.

[0090] In another specific embodiment, at least about 90% of the225Ac labeled J591 tetraxetan in the composition is in the form of a monomer. In another specific embodiment, at least about 91% of the225Ac labeled J591 tetraxetan in the composition is in the form of a monomer. In another specific embodiment, at least about 92% of225Ac labeled J591 tetraxetan in the composition is in the form of a monomer. In another specific embodiment, at least about 93% of the225Ac labeled J591 tetraxetan in the composition is in the form of a monomer. In another specific embodiment, at least about 94% of the225Ac labeled J591 tetraxetan in the composition is in the form of a monomer. In another specific embodiment, at least about 95% of the225Ac labeled J591 tetraxetan in the composition is in the form of a monomer. In another specific embodiment, at least about 96% of the225AC labeled J591 tetraxetan in the composition is in the form of a monomer. In another specific embodiment, at least about 97% of225Ac labeled J591 tetraxetan in the composition is in the form of a monomer. In another specific embodiment, at least about 98% of the225Ac labeledJ591 tetraxetan in the composition is in the form of a monomer. In another specific embodiment, at least about 99% of the225Ac labeled J591 tetraxetan in the composition is in the form of a monomer.

[0091] In another specific embodiment, the composition additionally comprises unconjugated or naked anti-PSMA antibody. In a specific embodiment, the unconjugated or naked anti-PSMA antibody is J591. In another embodiment, the unconjugated / naked anti-PSMA antibody has the same amino acid sequence as the conjugated anti-PSMA antibody. In another embodiment the total anti-PSMA antibody in the composition (unconjugated and conjugated) is at a concentration of 0.8 mg / mL to 1.2 mg / ml. In another embodiment, the overall weight of the total anti-PSMA antibody in the composition (unconjugated and conjugated) is about 10 mg, about 11 mg, about 12 mg, about 13 mg, about 14 mg, about 15 mg, about 16 mg, about 17 mg, about 18 mg, about 18 mg, about 19 mg, about 20 mg, about 21 mg, about 22 mg, about 23 mg, about 24 mg, about 25 mg, about 26 mg, about 27 mg, about 28 mg, about 29 mg, about 30 mg, about 31 mg, about 32 mg, about 33 mg, about 34 mg, about 35 mg, about 36 mg, about 37 mg, about 38 mg, about 39 mg, or about 40 mg.

[0092] In another specific embodiment, the composition is a pharmaceutical composition and comprises a single unit dose of conjugated anti-PSMA antibody chelated to225Ac wherein the pharmaceutical composition is about 18 to 22 ml in a saline solution containing about l%-2% human serum albumin.

[0093] In another embodiment, the composition of pharmaceutical composition comprises unconjugated or naked anti-PSMA antibody and conjugated anti-PSMA antibody chelated to225Ac, wherein the ratio of the unconjugated or naked anti-PSMA antibody to conjugated anti- PSMA antibody chelated to225Ac is about 30: 1 by weight, about 29: 1 by weight, about 28:1 by weight, about 27: 1 by weight, about 26: 1 by weight, about 25: 1 by weight, about 24: 1 by weight, about 23: 1 by weight, about 22: 1 by weight, about 21: 1 by weight, about 20:1 by weight, about 19: 1 by weight, about 18: 1 by weight, about 17:1 by weight, about 16:1 by weight, about 15:1 by weight, about 14:1 by weight, about 13:1 by weight, about 12: 1 by weight, about 11: 1 by weight, about 10:1 by weight, about 9: 1 by weight, about 8:1 by weight, about 7: 1 by weight, about 6: 1 by weight, about 5: 1 by weight, about 4: 1 by weight, about 3: 1 by weight, about 2: 1 by weight, about 1 : 1 by weight.

[0094] In another embodiment, the composition of pharmaceutical composition comprises unconjugated or naked anti-PSMA antibody and conjugated anti-PSMA antibody chelated to225Ac, wherein the ratio of conjugated anti-PSMA antibody chelated to225Ac to unconjugated or naked anti-PSMA antibody is about 30:1 by weight, about 29:1 by weight, about 28:1 by weight, about 27: 1 by weight, about 26: 1 by weight, about 25: 1 by weight, about 24:1 by weight, about 23: 1 by weight, about 22: 1 by weight, about 21 :1 by weight, about 20: 1 by weight, about 19: 1 by weight, about 18:1 by weight, about 17:1 by weight, about 16: 1 by weight, about 15: 1 by weight, about 14: 1 by weight, about 13: 1 by weight, about 12: 1 by weight, about 11 :1 by weight, about 10: 1 by weight, about 9:1 by weight, about 8: 1 by weight, about 7: 1 by weight, about 6:1 by weight, about 5: 1 by weight, about 4: 1 by weight, about 3: 1 by weight, about 2: 1 by weight, about 1 : 1 by weight.

[0095] In another embodiment, the composition of pharmaceutical composition comprises unconjugated or naked J591 and225Ac labeled J591 tetraxetan, wherein the ratio of the unconjugated or naked J591 to225Ac labeled J591 tetraxetan is about 30:1 by weight, about 29:1 by weight, about 28:1 by weight, about 27:1 by weight, about 26: 1 by weight, about 25:1 by weight, about 24: 1 by weight, about 23 : 1 by weight, about 22: 1 by weight, about 21: 1 by weight, about 20: 1 by weight, about 19: 1 by weight, about 18: 1 by weight, about 17:1 by weight, about 16: 1 by weight, about 15: 1 by weight, about 14:1 by weight, about 13:1 by weight, about 12:1 by weight, about 11 :1 by weight, about 10:1 by weight, about 9: 1 by weight, about 8:1 by weight, about 7: 1 by weight, about 6: 1 by weight, about 5: 1 by weight, about 4: 1 by weight, about 3: 1 by weight, about 2: 1 by weight, about 1 : 1 by weight.

[0096] In another embodiment, the composition of pharmaceutical composition comprises unconjugated or naked J591 and225Ac labeled J591 tetraxetan, wherein the ratio of the225Ac labeled J591 tetraxetan to unconjugated or naked J591 is about 30: 1 by weight, about 29:1 by weight, about 28:1 by weight, about 27:1 by weight, about 26: 1 by weight, about 25: 1 by weight, about 24: 1 by weight, about 23: 1 by weight, about 22: 1 by weight, about 21 :1 by weight, about 20: 1 by weight, about 19: 1 by weight, about 18:1 by weight, about 17:1 by weight, about 16: 1 by weight, about 15:1 by weight, about 14:1 by weight, about 13: 1 by weight, about 12: 1 by weight, about 11: 1 by weight, about 10: 1 by weight, about 9: 1 by weight, about 8: 1 by weight, about 7:1 by weight, about 6:1 by weight, about 5:1 by weight, about 4:1 by weight, about 3:1 by weight, about 2: 1 by weight, about 1 : 1 by weight.

[0097] In another embodiment, the composition of pharmaceutical composition comprises unconjugated or naked anti-PSMA antibody and conjugated anti-PSMA antibody chelated to225Ac, wherein the ratio of conjugated anti-PSMA antibody chelated to225Ac to unconjugated or naked anti-PSMA antibody ranges in the ratio of about 40: 1 to about 1:40 by weight, about 30:1 to about 1:30 by weight, about 20: 1 to about 1:20 by weight, about 10:1 to about 1:10 by weight, about 30:1 to about 1: 1 by weight, about 20:1 to about 1 :1 by weight, about 15: 1 to about 1:1 by weight, about 10: 1 to about 1 : 1 by weight, about 1 :30 to about 1 : 1 by weight, about 1 :20 to about 1 : 1 by weight, about 1 : 15 to about 1 : 1 by weight, or about 1 : 10 to about 1 : 1 by weight.

[0098] In another embodiment, the composition of pharmaceutical composition comprises unconjugated or naked J591 and225Ac labeled J591 tetraxetan, wherein the ratio of the unconjugated or naked J591 to225Ac labeled J591 tetraxetan ranges in the ratio of about 40:1 to about 1:40 by weight, about 30: 1 to about 1 :30 by weight, about 20: 1 to about 1 :20 by weight, about 10:1 to about 1 : 10 by weight, about 30: 1 to about 1 : 1 by weight, about 20: 1 to about 1 : 1 by weight, about 15:1 to about 1:1 by weight, about 10:1 to about 1: 1 by weight, about 1:30 to about 1 : 1 by weight, about 1 : 20 to about 1 : 1 by weight, about 1 : 15 to about 1 : 1 by weight, or about 1 :10 to about 1 : 1 by weight.

[0099] In another embodiment, the composition or pharmaceutical composition, including the bulk composition or the single unit dose composition, may have a particular immunoreactivity. The conjugation of chelating agents to an antibody as well as labeling procedure or radiolysis during antibody storage may adversely alter the antibody and affect the immunoreactivity. Unfavorable in vivo behavior of radioimmunopharmaceuticals, such as reduced tumor uptake, increased nonspecific localization and radiation exposure of nontarget tissues, can be result. Therefore, the determination of immunoreactive fraction (IRF) is essential to ensure the efficacy and stability of radiolabeled antibodies, including the drug product. In a specific embodiment, the immunoreactivity or IRF of225Ac labeled anti-PSMA antibody conjugate (such as225Ac labeled J591 tetraxetan) is tested as described in J. Immunol. Methods 1984, 72 (1), 77- 89. In another embodiment, the immunoreactivity or IRF of225Ac labeled anti-PSMA antibody conjugate (such as225Ac labeled J591 tetraxetan) is tested as described in NuclMed Biol. 2019 Apr; 71 : 32-38 by using PSMA-bound magnetic beads. In a specific embodiment, the composition or pharmaceutical composition comprises225Ac labeled anti-PSMA antibody conjugate (such as225Ac labeled J591 tetraxetan), wherein the immunoreactive fraction (IRF) of225Ac labeled anti-PSMA antibodyconjugate (such as225Ac labeled J591 tetraxetan) is at least 60%, or at least 65%, or at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95%. In another embodiment, the IRF is determined using PSMA-bound magnetic beads. In another specific embodiment, the IRF is determined as in in Nucl Med Biol. 2019 Apr; 71 : 32-38.

[0100] In another specific embodiment, the immunoreactive fraction (IRF) of a composition or pharmaceutical composition comprising225Ac labeled J591 tetraxetan is at least 60%, or at least 70%, or at least 80%, or at least 90%, or at least 91%, or at least 92%, or at least 93%, or at least 94%, or at least 95%, or at least 96%, or at least 97%, or at least 98%, or at least 99%, or about 100%. In another specific embodiment, the IRF values are determined 7 days or less before administration to a patient. In another specific embodiment, the IRF value is determined by using PSMA-bound magnetic beads. In another specific embodiment, the IRF value is determined as or substantially similar as in Example 5, Example 6, or Example 7 described herein.

[0101] In a further embodiment of the present invention, a composition or pharmaceutical composition comprising a225Ac labeled anti-PSMA antibody conjugate (such as225Ac labeled J591 tetraxetan) and a pharmaceutically acceptable excipient or carrier is provided. In a specific embodiment, the compositions or pharmaceutically acceptable compositions may include bulk compositions or single use compositions, or single unit dose formulations as describe herein, and include a pharmaceutically acceptable carrier which may include a pharmaceutically acceptable excipient, binder, and / or diluent. In one embodiment, suitable pharmaceutically acceptable excipients include, but are not limited to, water, salt solutions, alcohol, polyethylene glycols, gelatin, lactose, amylase, magnesium stearate, talc, silicic acid, viscous paraffin, hydroxymethylcellulose and polyvinylpyrrolidone. Suitable formulations or pharmaceuticals for various methods of administration can be found, for example, in Remington: The Science and Practice of Pharmacy, A. Gennaro, ed., 20th edition, Lippincott, Williams & Wilkins, Philadelphia, PA.

[0102] In one embodiment, suitable pharmaceutically acceptable carriers include, but are not limited to, inert diluents and sterile aqueous or organic solutions. Pharmaceutically acceptable carriers are well known to those skilled in the art and include, but are not limited to, from about 0.01 to about 0.1 M and preferably 0.05M phosphate buffer or saline. Such pharmaceuticallyacceptable carriers can be aqueous or non-aqueous solutions, suspensions and emulsions. Examples of non-aqueous solvents suitable for use in the present application include, but are not limited to, propylene glycol, polyethylene glycol, vegetable oils such as olive oil, and injectable organic esters such as ethyl oleate.

[0103] Aqueous carriers suitable for use in the present application include, but are not limited to, water, ethanol, alcoholic / aqueous solutions, glycerol, emulsions or suspensions, including saline and buffered media.

[0104] In one embodiment, the pharmaceutical composition is in PlasmaLyte® which contains 0.8- 8% sucrose, 0.002% Polysorbate 80 (PS80), and 0.001- 1% glycerol.

[0105] Liquid carriers suitable for use in the present application can be used in preparing solutions, suspensions, emulsions, syrups, elixirs and pressurized compounds. The active ingredient can be dissolved or suspended in a pharmaceutically acceptable liquid carrier such as water, an organic solvent, a mixture of both or pharmaceutically acceptable oils or fats.

[0106] Liquid carriers suitable for use in the present application include, but are not limited to, water (partially containing additives as above, e.g. cellulose derivatives, preferably sodium carboxymethyl cellulose solution), alcohols (including monohydric alcohols and polyhydric alcohols, e.g. glycols) and their derivatives, and oils (e.g. fractionated coconut oil and arachis oil).

[0107] Liquid pharmaceutical compositions can contain emulsifying agents to disperse uniformly throughout the composition and / or combination an active ingredient or other excipient that is not soluble in the liquid carrier. Emulsifying agents that may be useful in liquid compositions and / or combinations of the present invention include, for example, gelatin, egg yolk, casein, cholesterol, acacia, tragacanth, chondrus, pectin, methyl cellulose, carbomer, cetostearyl alcohol, and cetyl alcohol.

[0108] Preservatives and chelating agents such as alcohol, sodium benzoate, butylated hydroxyl toluene, butylated hydroxyanisole, and ethylenediamine tetraacetic acid may be added at levels to improve storage stability.

[0109] In some embodiments, the compositions or pharmaceutical compositions described herein include antimicrobial agents, which may include antibiotics, antifungals, antivirals, and / or bacteriostatic agents. In some embodiments, the antimicrobial agent is ethylenediaminetetraacetic acid disodium salt.

[0110] A liquid composition can also contain a buffer such as guconic acid, lactic acid, citric acid or acetic acid, sodium guconate, sodium lactate, sodium citrate, or sodium acetate. Selection of excipients and the amounts used may be readily determined by the formulation scientist based upon experience and consideration of standard procedures and reference works in the field.

[0111] In one embodiment, a pharmaceutical composition is prepared for administration by injection (e.g., intravenous, subcutaneous, intramuscular, etc.). In certain of such embodiments, a pharmaceutical composition comprises a carrier and is formulated in aqueous solution, such as water or physiologically compatible buffers such as Hanks's solution, Ringer's solution, or physiological saline buffer. In certain embodiments, other ingredients are included (e.g., ingredients that aid in solubility or serve as preservatives). In certain embodiments, injectable suspensions are prepared using appropriate liquid carriers, suspending agents and the like. Certain pharmaceutical compositions for injection are presented in unit dosage form, e.g., in ampoules, vials, or in multi-dose containers. Certain pharmaceutical compositions for injection are suspensions, solutions or emulsions in oily or aqueous vehicles, and may contain formulatory agents such as suspending, stabilizing and / or dispersing agents. Certain solvents suitable for use in pharmaceutical compositions for injection include, but are not limited to, lipophilic solvents and fatty oils, such as sesame oil, synthetic fatty acid esters, such as ethyl oleate or triglycerides, and liposomes. Aqueous injection suspensions may contain substances that increase the viscosity of the suspension, such as sodium carboxymethyl cellulose, sorbitol, or dextran. Optionally, such suspensions may also contain suitable stabilizers or agents that increase the solubility of the pharmaceutical agents to allow for the preparation of highly concentrated solutions.

[0112] A sterile injectable preparation may also be a sterile injectable solution or suspension in a non-toxic parenterally acceptable diluent or solvent, such as a solution in 1,3-butane-diol or prepared as a lyophilized powder. Among the acceptable vehicles and solvents that may be employed are water, Ringer's solution and isotonic sodium chloride solution. In addition, sterilefixed oils may conventionally be employed as a solvent or suspending medium. For this purpose any bland fixed oil may be employed including synthetic mono- or diglycerides. In addition, fatty acids such as oleic acid may likewise be used in the preparation of injectables. Formulations for intravenous administration can comprise solutions in sterile isotonic aqueous buffer. Where necessary, the formulations can also include a solubilizing agent and a local anesthetic to ease pain at the site of the injection. Generally, the ingredients are supplied either separately or mixed together in unit dosage form, for example, as a dry lyophilized powder or water free concentrate in a hermetically sealed container such as an ampule or sachet indicating the quantity of active agent. Where the composition is administered by injection, an ampule of sterile water for injection or saline can be provided so that the ingredients can be mixed prior to administration.

[0113] Suitable formulations further include aqueous and non-aqueous sterile injection solutions that can contain antioxidants, buffers, bacteriostats, bactericidal antibiotics and solutes that render the formulation isotonic with the bodily fluids of the intended recipient; and aqueous and nonaqueous sterile suspensions, which can include suspending agents and thickening agents.

[0114] In other embodiments the composition of the present disclosure are administered by the intravenous route. In further embodiments, the parenteral administration may be provided in a bolus or by infusion.

[0115] In a specific embodiment, the pharmaceutical composition may comprise pharmaceutically acceptable carrier or excipients for Ac-225-radiopharmaceutical(s) and may include saline and / or human serum albumin (HSA). In a specific embodiment, the pharmaceutical composition may comprise saline containing a 0.3% to 5% HSA solution, or a 0.5% to 5% HSA solution, or a 0.7% to 3% HSA solution, or a 1.0% to 3% HSA solution, or a 1.5% to 2.5% HSA solution. In another embodiment, the composition or pharmaceutical composition may include a stabilizer or additional excipients to prevent radiolysis, or aggregation of antibodies such as ascorbic acid, gentisic acid, or the like.

[0116] The pharmaceutical compositions of the present disclosure may be manufactured and / or administered in single or multiple unit dose forms.

[0117] In another embodiment, the pharmaceutical compositions or methods of the presentation of the present invention may include one or more additional pharmaceutical agents or PSMA receptor inhibitors. In a specific embodiment, the presentation invention may comprise pharmaceutical combinations comprising the pharmaceutical compositions herein and one or more additional pharmaceutical agents or PSMA receptor inhibitors. In another specific embodiment, the methods may include administering to a patient or subject in need thereof a pharmaceutical combination comprising a pharmaceutical composition described herein and one or more additional pharmaceutical agents or PSMA receptor inhibitors for the treatment of cancer, such as prostate cancer. In a specific embodiment, the pharmaceutical combination may comprise a pharmaceutical composition described herein and a second separate pharmaceutical combination comprising the one or more additional pharmaceutical agents or PSMA receptor inhibitors.

[0118] In a specific embodiment, the PSMA receptor inhibitor may include any lipids, carbohydrates, polynucleotides, peptides, polypeptides, or any other biologic, organic or inorganic molecules which inhibit the function of the PSMA receptor. Exemplary PSMA receptor inhibitors are known in the art include, but are not limited to, PSMA 617, PSMA I&T, DCFBC, DCFPyL, glutamate-urea-lysine analogs, phosphoramidate analogs, and 2-(phosphinylmethyl) pentanedioic acid analogs (Lutje et al., “PSMA Ligands for Radionuclide Imaging and Therapy of Prostate Cancer: Clinical Status,” Theranostics 5(12): 1388-1401 (2015); Haberkorn et al., “New Strategies in Prostate Cancer: Prostate-Specific Membrane Antigen (PSMA) Ligands for Diagnosis and Therapy,” Clin. Cancer Res. 22(1):9-15 (2016), which are hereby incorporated by reference in their entirety). In one embodiment, the PSMA receptor inhibitor is a peptide selected from the group consisting of PSMA 617, PSMA I&T, DCFBC, DCFPyL, glutamate-urea-lysine analogs, phosphoramidate analogs, 2-(phosphinylmethyl) pentanedioic acid analogs, and other PSMA ligands / inhibitors. In one embodiment, the additional agent or PSMA receptor inhibitor is PSMA 617-177LU or PSMA I&T-177Lu. By way of example, the PSMA receptor antibodies can be radiolabeled with " 'indium,90Yttrium, or177Lutetium by coupling with 1,4,7,10- tetraazacyclododecane-N,N',N",N'"-tetraacetic acid (DOTA) as described in U.S. Pat. No. 7,045,605 to Bander, which is hereby incorporated by reference in its entirety.Methods of producing a225Ac labeled anti-PSMA antibody

[0119] Procedures for labeling agents with radioactive isotopes are generally known in the art and described for example in WO2018204477, which is incorporated by reference herein in its entirety. For example, there are a wide range of moieties which can serve as chelating ligands and which can be derivatized to the targeting component of the invention. For instance, the chelating ligand can be a derivative of 1,4,7,10-tetraazacyclododecanetetraacetic acid (DOTA), ethyl enediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTP A), and 1-p- Isothiocyanato-benzyl-methyl-diethylenetriaminepentaacetic acid (ITC-MX). These chelators typically have groups on the side chain by which the chelator can be used for attachment to a targeting component of the present invention. Such groups include, e.g., benzylisothiocyanate, by which the DOTA, DTP A, or EDTA can be coupled to, e.g., an amine group of the targeting component. Procedures for iodinating biological agents, such as antibodies, binding portions thereof, probes, or ligands, are described by Hunter and Greenwood, “Preparation of Iodine-131 Labelled Human Growth Hormone of High Specific Activity,” Nature 144:496-496 (1962), David et al., “Protein Iodination With Solid State Lactoperoxidase,” Biochemistry 13: 1014-1021 (1974), and U.S. Patent Nos. 3,867,517 to Ling and 4,376,110 to David, which are hereby incorporated by reference in their entirety. Other procedures for iodinating biological agents are described by Greenwood et al., “The Preparation of 1-131 -Labelled Human Growth Hormone of High Specific Radioactivity,” Biochem. J. 89: 114-123 (1963); Marchalonis, “An Enzymic Method for the Trace Iodination of Immunoglobulins and Other Proteins,” Biochem. J. 1137 :299- 305 (1969); and Morrison et al., ’’“Use of Lactoperoxidase Catalyzed Iodination in Immunochemical Studies,” Immunochemistry 8:289-297 (1971), which are hereby incorporated by reference in their entirety. Procedures for 99m Tc-labeling are described by Rhodes, B. et al. in Burchiel, S. et al. (eds.), “Tumor Imaging: The Radioimmunochemical Detection of Cancer, New York: Masson 111-123” (1982) and the references cited therein, which are hereby incorporated by reference in their entirety. Procedures suitable for 111 In-labeling biological agents are described by Hnatowich et al., “The Preparation of DTPA-coupled Antibodies Radiolabeled With Metallic Radionuclides: an Improved Method,” J Immul. Methods 65: 147-157 (1983), Hnatowich et al., “Coupling Antibody With DTPA-an Alternative to the Cyclic Anhydride,” Int. J. Applied Radiation 35:554-557 (1984), and Buckley et al., “An Efficient Method For Labelling.” FEBS letters 1984; 166:202- 204. All of which are hereby incorporated by reference in their entirety.

[0120] In a specific embodiment, the methods of the present invention include a method of producing a composition or pharmaceutical composition comprising a conjugated anti-PSMA antibody described herein. In another specific embodiment, the methods comprise conjugating a chelator to an anti-PSMA antibody such as conjugating DOTA to an anti-PSMA antibody comprising adding a 3-arm DOTA-NHS to the anti-PSMA antibody, wherein the DOTA is covalently linked to the anti-PSMA antibody in an average ratio range of about 5 DOTAs per anti- PSMA antibody to about 3 DOTAs per anti-PSMA antibody. In a specific embodiment, the anti- PSMA antibody or an anti-PSMA antibody fragment is conjugated to DOTA wherein the DOTA is covalently linked to the anti-PSMA antibody in an average ratio range of about 1 DOTA per anti-PSMA antibody or anti-PSMA antibody fragment to about 10 DOTAs per anti-PSMA antibody or anti-PSMA antibody fragment. In another embodiment, the anti-PSMA antibody or an anti-PSMA antibody fragment is conjugated to a chelator wherein the DOTA is covalently linked to the anti-PSMA antibody in an average ratio range of about 1 DOTA per anti-PSMA antibody or anti-PSMA antibody fragment to about 10 DOTAs per anti-PSMA antibody or anti-PSMA antibody fragment. In another embodiment, the anti-PSMA antibody or an anti-PSMA antibody fragment is conjugated to a DOTA wherein the DOTA is covalently linked to the anti-PSMA antibody in an average ratio range of about 2 DOTAs per anti-PSMA antibody or anti-PSMA antibody fragment to about 9 DOTAs per anti-PSMA antibody or anti-PSMA antibody fragment. In another embodiment, the anti-PSMA antibody or an anti-PSMA antibody fragment is conjugated to a chelator wherein the DOTA is covalently linked to the anti-PSMA antibody in an average ratio range of about 2 DOTAs per anti-PSMA antibody or anti-PSMA antibody fragment to about 8 DOTAs per anti-PSMA antibody or anti-PSMA antibody fragment. In another embodiment, the anti-PSMA antibody or an anti-PSMA antibody fragment is conjugated to a DOTA wherein the DOTA is covalently linked to the anti-PSMA antibody in an average ratio range of about 3 DOTAs per anti-PSMA antibody or anti-PSMA antibody fragment to about 7 DOTAs per anti-PSMA antibody or anti-PSMA antibody fragment. In another embodiment, the anti-PSMA antibody or an anti-PSMA antibody fragment is conjugated to a DOTA wherein the DOTA is covalently linked to the anti-PSMA antibody in an average ratio range of about 3 DOTAs per anti-PSMA antibody or anti-PSMA antibody fragment to about 5 DOTAs per anti-PSMA antibody or anti-PSMA antibody fragment. In another embodiment, the anti-PSMA antibody is J591. In another embodiment, the chelator is DOTA.

[0121] In a specific embodiment, the methods include conjugating DOTA to an anti-PSMA antibody by adding a 3 -arm DOTA-NHS to the anti-PSMA antibody at a ratio ranging from about 500:1 to about 100:1 DOTA-NHS to the anti-PSMA antibody, or about 400: 1 to about 200: 1 DOTA-NHS to the anti-PSMA antibody, or about 300: 1 DOTA-NHS to the anti-PSMA antibody, wherein the DOTA is covalently linked to the anti-PSMA antibody in an average ratio range of about 5 DOTAs per anti-PSMA antibody to about 3 DOTAs per anti-PSMA antibody. In another specific embodiment, the anti-PSMA antibody comprises: (i) an immunoglobulin heavy chain variable region comprising SEQ ID NO: 1; and (ii) an immunoglobulin light chain variable region comprising SEQ ID NO: 2. In another specific embodiment, at least 90% of the anti-PSMA antibody in the composition is conjugated with about 2-7 or about 3-5 DOTAs.

[0122] In another specific embodiment, the method of conjugating DOTA to an anti-PSMA antibody at a ratio of about 300: 1 DOTA-NHS to the anti-PSMA antibody, wherein the DOTA is covalently linked to the anti-PSMA antibody in an average ratio range of about 5 DOTAs per anti- PSMA antibody to about 3 DOTAs per anti-PSMA antibody. In another specific embodiment, the anti-PSMA antibody is J591.

[0123] In another specific embodiment, the conjugation reaction is performed wherein the DOTA / J591 ratio is about 300: 1, the NHS / J591 ratio is about 300:1, and the EDC / J591 ratio is about 22.

[0124] In another embodiment, the methods include chelating225Ac to a chelator conjugated anti- PSMA antibody, including the conjugated anti-PSMA antibodies as described herein. In another embodiment, the methods include chelating225Ac to a DOTA conjugated anti-PSMA antibody comprising adding225AcCh to a reaction vial comprising 2M tetramethyl ammonium acetate (TMAA) buffer, 0.85 M ascorbic acid. In another embodiment, the methods include the addition step of incubating the DOTA conjugated anti-PSMA antibody in a pH adjusted to 5.5-6.2, and incubating at 37° C for 2 hours. In another embodiment, the methods include a quenching reaction step by adding a metal-free lOmM DTPA solution to the reaction vial, and incubating at 37° C for 10 min. In another embodiment, the methods include the additional step of purifying the225Ac DOTA conjugated anti-PSMA antibody using a PD-10 column and by eluting it from the column using sterile saline containing 2% human serum albumin (HSA), wherein at least 95% of the conjugated anti-PSMA antibody is chelated to225Ac.

[0125] In another embodiment, the methods include: 1) chelating225Ac to a DOTA conjugated anti-PSMA antibody comprising adding225AcCb to a reaction vial comprising 2M tetramethyl ammonium acetate (TMAA) buffer, 0.85 M ascorbic acid; 2) incubating the DOTA conjugated anti-PSMA antibody in a pH adjusted to 5.5-6.2, and incubating at about 37° C for about 2 hours; 3) quenching the reaction by adding a metal-free lOmM DTPA solution to the reaction vial, and incubating at about 37° C for about 10 min; and 4) purifying the225Ac DOTA conjugated anti- PSMA antibody. In a specific embodiment, the purification step comprises using a PD-10 column and by eluting it from the column using sterile saline containing 2% human serum albumin (HSA), wherein at least 95% of the conjugated anti-PSMA antibody is chelated to225Ac. In a specific embodiment, the methods may include any one of steps 1-4 described above or combination of 1, 2 or 3 of the 4 steps described above.

[0126] In some embodiments, the purification step includes a post radiolabeling purification which may includes a size exclusion column, volume, a protein A column and / or an HIC column, for example.

[0127] In another specific embodiment, the225Ac to a DOTA conjugated anti-PSMA antibody is225Ac labeled J591 tetraxetan. In another specific embodiment, the DOTA conjugated anti-PSMA antibody or225Ac labeled J591 tetraxetan made by the methods described herein is incorporated in a composition or a pharmaceutical composition, including one or more pharmaceutical carriers or excipients described herein.Therapeutic use

[0128] The pharmaceutical compositions are useful in methods for treating cancer.

[0129] In certain embodiments, the pharmaceutical compositions of the present invention may be administered to a patient or subject in need thereof for the treatment of cancer. In a specific embodiment, the cancer is prostate cancer. In some embodiments, the cancer is a primary tumor, while in other embodiments, the cancer is a secondary or metastatic tumor. In embodiments, the cancer is a PSMA expressing cancer. In embodiments, the prostate cancer is metastatic castrationresistant prostate cancer (mCRPC). In some embodiment, the prostate cancer is castration-sensitive prostate cancer.

[0130] In a specific embodiment, tthe pharmaceutical compositions of the present invention may be administered to a patient or subject in need thereof for the treatment of cancer wherein the initial dose is a pharmaceutical composition as described herein.

[0131] In another embodiment, the pharmaceutical compositions comprising the225Ac to a DOTA conjugated anti-PSMA antibody is225Ac labeled J591 tetraxetan described herein and is administered to a patient or subject in need thereof for the treatment of cancer. In a specific embodiment, the cancer is prostate cancer. In another specific embodiment, the cancer is a PSMA expressing cancer. In another specific embodiment, the cancer is mCRPC. In another specific embodiment, the prostate cancer is castration-sensitive prostate cancer. In another specific embodiment, the methods include administering one or more doses to a patient, wherein the initial dose is a pharmaceutical composition described herein. In another embodiment second or later dose administered to the patient is a pharmaceutical composition described herein. In another specific embodiment, the second dose is administered two to three weeks after the initial dose.

[0132] The disclosure now being generally described, it will be more readily understood by reference to the following examples which are included merely for purposes of illustration of certain aspects and embodiments of the present invention, and are not intended to limit the invention.EXAMPLES

[0133] Example 1: Prior art Method of Preparation of225Ac Complexes and Conjugates

[0134] The preparation of the225Ac complexes is described in U.S. Patent No. 6,683,162, and is incorporated by reference herein, involves a 2-step labeling method to prepare mCi amounts of Ac- 225 labeled DOTA-NCS species at pH 4.5-5 in acetate buffer at 55-60° C. for 30 min. in high yield (95% +8%, n=36); subsequently, the [Ac-225]DOTA-NCS is mixed with J591 antibody in carbonate buffer at pH 8.5-9 at 37° C. for 30 min. The final product is purified by size exclusion chromatography using a 10 mL BioRad 10DG column and 1% HSA. Typical reaction yields are 10%±5%. Constructs thus prepared are assayed using established ITLC methods that quantify labeled J591, free [Ac-225] chelate and unbound Ac-225 and cell-based immunoreactivity assays.

[0135] Example 2: High Purity DOTA Activation and Conjugation to J591 anti-PSMA antibody

[0136] The J591 antibody is produced by a NS0 or CHO cell and purified from the supernatant.

[0137] DOTA powder and NHS powder were weighed and dissolved into a 0.4 M NaHCOs solution. EDC powder was then dissolved in water and is added to the DOTA / NHS solution. The DOTA activation was allowed to proceed for 45 (30-60) min at 5 (4-6) °C to form a DOTA-NHS ester, with a structure as below.

[0138] Before conjugation, the ultrafiltration / diafiltration (UF / DF-1) pool was transferred from a 10L PC bottle to a conjugation reactor. For the conjugation reaction, the DOTA / J591 antibody ratio was a molar ratio of 300, the NHS / J591 was a molar ratio of 300, the NaHCCh / DOTA molar ratio was 3, and EDC / J591 molar ratio was 22. The UF / DF-1 pool was diluted with conjugation buffer (0.1 M K2HPO4, 0.1 M NaHCCh, pH 8.5) to concentration of 7.5 g / L. The activated DOTA- NHS ester was then added into the diluted UF / DF-1 pool to start the conjugation reaction using an addition time of 4 (< 5) min. The conjugation was allowed to proceed for 90 (range of 60-180) min at 20 (range of 17-23) °C.

[0139] To quench the conjugation reaction, a 1.5 M NH2OH solution was added to achieve a hydroxylammonium chloride / DOTA molar ratio of 5.0. The quenching reaction was allowed to proceed for 1.0 (range of 0.5 -1.5) hours at 20 (range of 18-22) °C. The quenched mixture was then diluted with conjugation buffer (0.1 M K2HPO4, 0.1 M NaHCCh, pH 8.5) to a concentration of 4.0 (3.0-5.0) g / L and filtered through a 0.2 pm filter into a PC bottle. The results show that an average ratio range of about 3 DOTAs per J591 antibody to about 5 DOTAs per J591 antibody

[0140] Example 3: Manufacturing of pure225Ac labeled conjugated J591

[0141] The addition of Actinium (225Ac) to conjugated J591 antibody as developed in Example 2 above is accomplished in two phases. In the first phase, a multi-dose Bulk-Batch of225Ac labeled J591 tetraxetan (from Example 2) is manufactured and was allowed for225Ac to reach secular equilibrium with its two daughters,221Fr and213Bi. The equilibrium process lasted longer than 6 hours, and was a critical step to accurately measure the amount of225Ac activity needed to prepare a patient-specific unit-dose of Actinium (225Ac) J591 tetraxetan.

[0142] In the second phase, sub-batches were prepared with different aliquots of the Bulk-batch and mixing them with naked, unconjugated J591 to achieve a total antibody mass of about 20 mg. The volume of each sub-batch was adjusted to 18-22 mL using the diluent, sterile saline containing 2% (or 20 mg / mL) of human serum albumin (HSA). Finally, the total volume of each sub-batch was sterile filtered using a 0.2 p membrane filter directly into the FDP vial, the container-closure system. QC and retain samples were withdrawn from each sub-batch.

[0143] Preparation of225Ac Chloride

[0144] 225Ac nitrate (as dry residue) was first converted to225Ac chloride, by adding 0.2 M hydrochloric acid (0.2 M) to make a 10 mCi / mL solution.

[0145] Radiolabeling Mixture

[0146] 0.25 mL of tetramethyl ammonium acetate (TMAA) buffer (2M, pH 8.5±0.3) was then added225Ac chloride (0.4-0.5 or 0.7-1.0 mCi), The contents were then gently mixed, followed by the addition of 0.3 or 0.6 mL (or 3 or 6 mg) of the conjugated J591 tetraxetan antibody (10 mg / mL). The contents were gently mixed. The pH of the reaction mixture was measured and adjusted with 0.1 M HC1 to 5.5 - 6.2.

[0147] Incubation: Radiolabeling

[0148] The reaction mixture was allowed to incubate for 2±0.25 hours at 37±1°C. If the labeling efficiency (LE) is >50%, the reaction is quenched.

[0149] Quenching the Reaction and Purification

[0150] At the end of incubation time, the labeling reaction was quenched by adding 0.1 mL of diethylenetriamine pentaacetate (DTP A) solution (10 mM), and incubated for 10 min. The225Aclabeled J591 tetraxetan was then purified from free225Ac-DTPA using a gel filtration method with 10 DG desalting column and sterile saline with 2% human serum albumin (saline-HSA) as an eluent. The225Ac labeled J591 tetraxetan was collected using 3.5 mL of eluent. The volume of purified labeled product was adjusted to 5 or 10 mL using saline-HSA solution.

[0151] The total volume (5 or 10 mL) was then sterile filtered directly into a 10 mL sterile and pyrogen-free vial using 0.2 p membrane filter. In addition, a QC sample was withdrawn to perform several in-process quality control tests.

[0152] This Bulk-batch vial was stored at 2-8°C for 6-24 hours to allow225Ac to reach secular equilibrium with its daughters. Once equilibrium was reached, the amount of225Ac activity was measured in a dose calibrator and activity was confirmed. Individual batches may then be drawn from this bulk batch.

[0153] Preparation of Sub-Batches

[0154] Once the secular equilibrium was reached, the Bulk-batch was used to prepare 1-3 subbatches. A patient specific225Ac dose of intermediate from Bulk-batch (90-220 pCi in 1-3 mL) was estimated and corrected for decay; QC and retain samples were taken. The volume of the intermediate is then mixed (in a 30 ml sterile syringe) with naked unconjugated J591 to bring the total antibody mass to 22 mg. The volume is then adjusted to 22 mL with sterile saline-HSA solution.

[0155] The total volume of each sub-batch solution was sterile filtered directly into a 30 mL sterile and pyrogen-free vial (container-closure system) using 0.2p sterile membrane filter. The225Ac activity in each of the sub-batches was measured and documented. After testing for appearance (visual inspection), QC and retain samples (1.2 mL) were withdrawn from each of the sub-batch vials. The vials with patient-specific unit-doses were again measured for total225Ac activity and documented as the calibration or reference time.

[0156] Example 4: Monomer Purity Assay

[0157] The sub batches from Example 3 were tested to confirm purity. The monomer purity, high molecular weight and low molecular weight impurities were analyzed by high performance liquid chromatography-size exclusion chromatography-(HPLC-SEC). As indicated in Fig. 1, at least96% of225Ac labeled J591 tetraxetan was determined to be in the monomer form, less than 4% of225Ac labeled J591 tetraxetan was determined to be in a high molecular form, and the amount of low molecular weight impurities is negligible to undetected, indicating that the conjugation and chelation process do not substantially adversely affect the purity of J591 and the composition comprising225Ac labeled J591 tetraxetan is stable.

[0158] Example 5: Immunoreactivity Assay

[0159] The sub batches of Example 4 are tested for immunoreactivity wherein the immunoreactive fraction (IRF)225Ac labeled J591 tetraxetan is tested. The testing is performed using PSMA-bound magnetic beads and a protocol as described in in Nucl Med Biol. 2019 Apr; 71: 32-38, which is incorporated by reference herein. Briefly, each sample is prepared by aliquoting 20 pL of the magnetic bead slurry into a 1.5 mL lo-bind microcentrifuge tube (13-698-794; Fisher Scientific). The beads are washed by adding 380 pL of phosphate-buffered saline containing 0.05% Tween- 20 (PBS-T), and the tubes are vortexed for 5 seconds followed by a brief spin in a minicentrifuge prior to placing the tubes on a magnetic rack (12321D; DynaMag™-2; ThermoFisher Scientific) for 30-45 sec to isolate the magnetic beads. The PSMA antigen is resuspended as per manufacturer instructions to achieve a concentration of a 0.1 mg / mL. The washed beads are resuspended in 390 pL of PBS-T and the beads in all tubes except the control arm are incubated with 1 pg (10 pL) of His-tagged or biotinylated PSMA antigen for 15 min on a rotating mixer at room temperature. Subsequently, the beads are washed once with 400 pL of PBS-T before adding 1 ng of the225Ac labeled J591 tetraxetan resuspended in 1% BSA-PBS or PBS-T. The225Ac labeled J591 tetraxetan is incubated with PSMA antigen-coated beads for 30 min on a rotating mixer at room temperature. A large excess (1-5 pg) of the unlabeled J591 is added a few seconds prior to adding 1 ng of the225Ac labeled J591 tetraxetan to PSMA antigen-coated beads in the blocking arm. Thereafter, the beads are isolated using a magnet, and the supernatant containing unbound radioligand was aspirated with a pipette and collected in separate tubes. To remove non-specifically-bound225Ac labeled J591 tetraxetan, the beads are washed twice with 400 pL of PBS-T. Finally, the beads, supernatant and washes are measured for radioactivity on a gamma counter. The225Ac labeled J591 tetraxetan IRF or TBF is determined from the percentage of total activity bound to PSMA antigen-coated magnetic beads minus the percentage of non-specific binding in the control arm.The assay indicates that the225Ac labeled J591 tetraxetan from Example 3 and 4 is immunoreactive and has an IRF of at least 60%.

[0160] Example 6: Immunoreactivity Assay

[0161] The225Ac labeled J591 tetraxetan from the bulk batch of Example 3 was tested for immunoreactivity, i.e., the immunoreactive fraction (IRF). First, 10 pl was taken from the bulk batch composition (diluted 1:500 in 1% HSA ) and added to 5.0 ml of PBS containing 1% HSA. 5 different volumes of PSMA-bound magnetic beads ( i.e., 1.0, 0.75, 0.5, 0.25, 0.125 mL) were added to separate plastic tubes and 0.5 ml of diluted bulk batch composition comprising225Ac labeled J591 tetraxetan was added to each of the plastic tubes comprising PSMA-bound magnetic beads. The mixture was incubated for 2 hrs. The tubes were then kept in a magnetic stand for 5 min to allow for separation of the antibody bound PSMA magnetic beads from the unbound antibody. The solution with the unbound antibody (unbound225Ac labeled J591 tetraxetan) was then removed. The antibody bound magnetic beads were then washing two or more times with PBS containing 1% HSA. The radioactivity of the beads from each tube was then tested in the gamma counter. A determination of %bound of each concentration of PSMA-beads was determined. A double reciprocal plot of bead concentration and %Bound is performed and the IRF at infinite antigen excess was determined. As shown in Fig. 2, the IRF at infinite antigen excess was 112%.

[0162] Example ?: Immunoreactivity Assay

[0163] The225Ac labeled J591 tetraxetan from the bulk batch of Example 3 is tested for immunoreactivity, i.e., the immunoreactive fraction (IRF).

[0164] The bulk batch is first diluted 1:500 in 1% HSA in phosphate buffered saline (PBS). The diluted bulk is added to 5 point-dilution series of PSMA bound magnetic beads as in Example 6) and to a set of standards. The various dilutions (test articles) and standards are first measured in the Gamma Counter and then incubated at 37°C for 2 hrs. with agitation. The test articles are then washed twice with 1% HSA in PBS and then suspended in 1 mL of 1% HSA in PBS. All test articles and standards are then measured in the Gamma Counter. The test articles and standardsare then stored at 2-8°C overnight to allow the225Ac to reach secular equilibrium (> 6 hrs). The test articles and standards are then measured again in the Gamma Counter. The counts per minute (CPM) for each test article are entered into a Lindmo Plot and the R2 value is recorded. The immunoreactive fraction is then determined using a double reciprocal plot of bound (1 / B) and concentration (1 / C) values; IRF is estimated at infinite antigen excess. The immunoreactive fraction of225Ac labeled J591 tetraxetan is determined by specific binding to PSMA bound magnetic beads. In a specific method, the %IRF is determined by taking the bound fraction (CPM) of the test article (can be the average CPM if more than 1 tube of test article is tested) divided by the average CPM of the standards.

[0165] Example 8: Purity of Prior art225Ac labeled J591 DOTA Conjugate

[0166] 225Ac labeled J591 DOTA conjugate from Example 1 tested to confirm purity and immunoreactivity. The monomer purity, high molecular weight and low molecular weight impurities are analyzed by high performance liquid chromatography-size exclusion chromatography-(HPLC-SEC). Only about 65% of225Ac labeled J591 tetraxetan is determined to be in the monomer form, and about 25-30% of225Ac labeled J591 is in a high molecular form, indicating an unstable composition comprising225Ac labeled J591.

[0167] The IRF is determined as in the protocol of Example 5, and indicates that the225Ac labeled J591 DOTA conjugate from Example 1 has a significantly lower IRF, i.e., less than 60%.

[0168] The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention.

[0169] While the invention has been described in connection with proposed specific embodiments thereof, it will be understood that it is capable of further modifications and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth and as follows in the scope of the appended claims.

[0170] Example 9: Formulation of225Ac labeled J591.

[0171] In a specific example, the final formulation of the225Ac labeled J591 to be administered to a patients is as follows:

Claims

WHAT IS CLAIMED IS:1) A composition comprising anti-PSMA antibody or an anti-PSMA antibody fragment, conjugated to a l,4,7,10-tetraazacyclododecane-l,4,7,10-tetraacetic acid (DOTA) chelator, wherein the DOTA chelator is covalently linked to the anti-PSMA antibody in an average ratio range of about 2 DOTAs per anti-PSMA antibody to about 7 DOTAs per anti-PSMA antibody.2) The composition of claim 1 , wherein the ratio range is about 3 DOTAs per anti-PSMA antibody to about 5 DOTAs per anti-PSMA antibody.3) The composition of claim 1 or 2, wherein the anti-PSMA antibody or anti-PSMA antibody fragment comprises: (i) an immunoglobulin heavy chain variable region comprising SEQ ID NO: 1; and (ii) an immunoglobulin light chain variable region comprising SEQ ID NO: 2.4) The composition of any one of claims 1-3, wherein the DOTA is conjugated in a 3 arm or 4 arm configuration with the anti-PSMA antibody.5) The composition of any one of claims 1-4, wherein the conjugated anti-PSMA antibody or anti-PSMA antibody fragment is chelated or complexed to225Ac.6) The composition of any one of claims 1-5, wherein at least 60%, or at least 65%, or at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95% of the anti-PSMA antibody is in the form of a monomer.7) The composition of claim 6, wherein at least 96%, 97%, 98%, or 99% of the anti-PSMA antibody is in the form of a monomer.8) The composition of claim 6 or 7, wherein the anti-PSMA antibody is in the form of a monomer as determined by HPLC-SEC.9) The composition of any one of claims 5-8, wherein at least about 85%, 90%, or 95% of the 225Ac activity in the composition is complexed or bound to conjugated anti-PSMA antibody.10) The composition of any one of claims 5-8, wherein at least 96% of the225Ac activity in the composition is complexed or bound to conjugated anti-PSMA antibody.11) The composition of claim 10, wherein at least 99% of the225Ac activity in the composition is complexed or bound to conjugated anti-PSMA antibody.12) The composition of claim 9, 10 or 11, wherein the percentage of225Ac activity bound or complexed by the conjugated anti-PSMA antibody is determined by HPLC-SEC.13) The composition of any one of claims 5-12, wherein the composition is substantially free of or contains less than 5% of unchelated of free225Ac.14) The composition of any one of claims 5-13, wherein the composition comprises a total of about 0.25 mCi to about 2.0 mCi from225Ac.15) The composition of any one of claims 5-13, wherein the composition comprises a total of about 0.5 mCi to about 1.0 mCi from225Ac.16) The composition of any one of claims 5-15, wherein the composition comprises a single unit dose of conjugated anti-PSMA antibody chelated to225Ac.17) The composition of claim 16, wherein the composition of a single unit dose comprises a total of about 50 pCi to 350 pCi of225Ac per 20 mg of anti-PSMA antibody.18) The composition of claim 17, wherein the composition comprises a single dose ranging from about 25 KBq / kg weight of a patient to about for about 100 KBq / kg weight of a patient.19) The composition of any one of claims 17-18, wherein the composition additionally comprises unconjugated / naked anti-PSMA antibody.20) The composition of claim 19, wherein the unconjugated / naked anti-PSMA antibody has the same amino acid sequence as the conjugated anti-PSMA antibody.21) The composition of claim 20, wherein the total anti-PSMA antibody in the composition (unconjugated and conjugated) is at a concentration of 0.8 mg / mL to 1.2 mg / ml.22) The composition of any one of claims 18-21, wherein the composition is about 18 to 22 ml in a saline solution containing about l%-2% human serum albumin.23) The composition of any one of claims 5-22, wherein the immunoreactive fraction (IRF) of 225Ac labeled anti-PSMA antibody is at least 50%, or at least 60%, or at least 70%, or at least 80%, or at least 90% or at least 95%, or at least 96%, or at least 97%, or at least 98%, or at least 99%, or at least or about 100%.24) The composition of any one of claims 5-22, wherein the immunoreactive fraction (IRF) value of225Ac labeled anti-PSMA antibody is determined using a protocol similar to Example 5, or determined in a protocol similar to Example 6.25) The composition of claim 23 or 24, wherein the IRF values are determined 10 days or fewer before administration to a patient.26) The composition of any one of claims 23-25, wherein the IRF value is determined by using PSMA-bound magnetic beads.27) The composition of any one of claims 1-26, wherein the composition is a pharmaceutical composition and additionally comprises one or more pharmaceutically acceptable carriers or excipients.28) A method of treating cancer in a patient in need thereof, comprising administering to the patient the pharmaceutical composition of claim 27.29) The method of claim 28, wherein the cancer is prostate cancer.30) The method of claim 28, wherein the cancer is a PSMA expressing cancer.31) The method of claim 28, wherein the cancer is mCRPC.32) The method of claim 29, wherein the prostate cancer is castration-sensitive prostate cancer.33) A method of treating cancer in a patient in need thereof, comprising administering one or more doses of the pharmaceutical composition of claim 27 to the patient.34) The method of claim 33, wherein the second or later dose is a pharmaceutical composition of claim 27.35) The method of claim 33 or 34, wherein the second dose is administered two to three weeks after the initial dose.36) A method of conjugating DOTA to an anti-PSMA antibody comprising adding a 3-arm DOTA- NHS to the anti-PSMA antibody at a ratio ranging from about 500: 1 to about 100: 1 DOTA- NHS to the anti-PSMA antibody, or about 400: 1 to about 200: 1 DOTA-NHS to the anti-PSMA antibody , or about 300: 1 DOTA-NHS to the anti-PSMA antibody, wherein the DOTA is covalently linked to the anti-PSMA antibody in an average ratio range of about 5 DOTAs per anti-PSMA antibody to about 3 DOTAs per anti-PSMA antibody.37) The method of claim 36, wherein the anti-PSMA antibody comprises: (i) an immunoglobulin heavy chain variable region comprising SEQ ID NO: 1; and (ii) an immunoglobulin light chain variable region comprising SEQ ID NO: 2.38) The method of claim 36, wherein at least 90% of the anti-PSMA antibody in the composition is conjugated with about 2-7 or about 3-5 DOTAs.39) A DOTA anti-PSMA antibody conjugate produced by the method of any one of claims 36-38.40) A method of chelating225Ac to a DOTA conjugated anti-PSMA antibody comprising, adding 225AcCb to a reaction vial comprising 2M tetramethyl ammonium acetate (TMAA) buffer, 0.85 M ascorbic acid.41) The method of claim 40, wherein the anti-PSMA antibody comprises: (i) an immunoglobulin heavy chain variable region comprising SEQ ID NO: 1; and (ii) an immunoglobulin light chain variable region comprising SEQ ID NO: 2.42) The method of claim 40 or 41, wherein at least 90% of the anti-PSMA antibody is in the form of a monomer.43) The method of claim 42, wherein at least 95% of the anti-PSMA antibody is in the form of a monomer.44) The method of claim 42 or 43, wherein at least 90% or at least 95% of the anti-PSMA antibody is in the form of a monomer as determined by HPLC-SEC.45) The method of any one of claims 40-44, wherein at least about 85%, 90%, or 95% of the225Ac activity in the composition is complexed or bound to conjugated anti-PSMA antibody.46) The method of claim 45, wherein at least 99% of the225Ac activity in the composition is complexed or bound to conjugated anti-PSMA antibody.47) The method of claim 45 or 45, wherein the percentage of225Ac activity bound or complexed by the conjugated anti-PSMA antibody is determined by HPLC-SEC.48) The method of any one of claims 40-47, wherein the composition is substantially free of or contains less than 5% of unchelated or free225Ac.49) The method of claim 48, wherein the DOTA anti-PSMA antibody conjugate is prepared by adding a 3-arm DOTA-NHS to the anti-PSMA antibody at a ratio ranging from about 500: 1 to about 100:1 DOTA-NHS to the anti-PSMA antibody, or about 400:1 to about 200: 1 DOTA- NHS to the anti-PSMA antibody , or about 300: 1 DOTA-NHS to the anti-PSMA antibody, wherein the DOTA is covalently linked to the anti-PSMA antibody in an average ratio range of about 5 DOTAs per anti-PSMA antibody to about 3 DOTAs per anti-PSMA antibody.50) A DOTA anti-PSMA antibody conjugate chelated to225Ac produced by the method of any one of claims 40-49.51) A pharmaceutical composition comprising the DOTA anti-PSMA antibody conjugate of chelated to225Ac of claim 50 and one or more pharmaceutically acceptable carriers or excipients.52) A composition comprising anti-PSMA antibody or an anti-PSMA antibody fragment, conjugated to a l,4,7,10-tetraazacyclododecane-l,4,7,10-tetraacetic acid (DOTA) chelator, wherein the DOTA chelator is chelated to225Ac and at least 90% of the anti-PSMA antibody is in the form of a monomer.53) The composition of claim 52, wherein at least 95% of the anti-PSMA antibody is in the form of a monomer.54) The composition of claim 52 or 53, wherein at least 90% or at least 95% of the anti-PSMA antibody is in the form of a monomer as determined by HPLC-SEC.55) The composition of any one of claims 52-54, wherein the immunoreactive fraction (IRF) value of225AC labeled anti-PSMA antibody is at least 60%, or at least 70% , or at least 80%, or at least 90%.56) The composition of any one of claims 52-55, wherein the anti-PSMA antibody or anti-PSMA antibody fragment comprises: (i) an immunoglobulin heavy chain variable region comprising SEQ ID NO: 1; and (ii) an immunoglobulin light chain variable region comprising SEQ ID NO: 2.57) A pharmaceutical composition comprising a single dose of anti-PSMA antibody or an anti- PSMA antibody fragment, conjugated to a 1 ,4,7, 10-tetraazacyclododecane- 1 ,4,7, 10-tetraacetic acid (DOTA) chelator, wherein the DOTA chelator is chelated to225Ac and, wherein the single dose ranges from about 25 KBq / kg weight of a patient to about for about 100 KBq / kg weight of a patient, and the pharmaceutical composition additionally comprises unconjugated anti- PSMA antibody, and one or more pharmaceutically acceptable carriers or excipients.58) The pharmaceutical composition of claim 57, wherein the unconjugated anti-PSMA antibody or anti-PSMA antibody fragment comprises the same amino acid sequence as the conjugated anti-PSMA antibody or an anti-PSMA antibody fragment.59) The pharmaceutical composition of claim 57 or 58, wherein the total anti-PSMA antibody (unconjugated and conjugated) is at a concentration of 0.8 mg / mL to 1.2 mg / ml.60) The pharmaceutical composition of any one of claims 57-59, wherein the anti-PSMA antibody or anti-PSMA antibody fragment comprises: (i) an immunoglobulin heavy chain variable region comprising SEQ ID NO: 1; and (ii) an immunoglobulin light chain variable region comprising SEQ ID NO: 2.

Images