Tumor antigen targeting agent, pharmaceutical composition, cancer diagnostic agent or cancer therapeutic agent, in vitro method, and compound thereof

Abstract

To provide compounds useful as therapeutic tracers, imaging agents and therapeutic agents for detecting tumor antigen-expressing target cells and tissues and treating and diagnosing cancer, such as PSMA-expressing target cells and tissues in a PSMA-related cancer, e.g., prostate cancer.SOLUTION: For example, a compound represented by a formula (1)(c) in the figure is provided, where D is a chelator and can complex a radionuclide, and a spacer comprises a C-N bond.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to novel compounds and radiolabeled conjugates comprising a tumor antigen-binding moiety (particularly a PSMA conjugate) and an albumin conjugate linked via a suitable linker and spacer, which are envisioned for use as diagnostic and / or therapeutic radiopharmaceuticals. Specifically, the compounds and conjugates of the present invention are useful as (therapeutic) tracers, imaging agents, and therapeutic agents for detecting tumor antigen-expressing target cells and tissues, such as PSMA-expressing target cells and tissues in PSMA-associated cancers (e.g., prostate cancer), and for treating and diagnosing cancer. [Background technology]

[0002] Prostate cancer is the most common type of cancer in men and the third leading cause of cancer death in Western countries (Non-Patent Documents 1 and 2). At least 1 to 2 million men in the Western Hemisphere are affected by prostate cancer, and the disease is estimated to affect one in six men aged 55 to 85. According to the American Cancer Society, approximately 161,000 new cases of prostate cancer are diagnosed each year in the United States. The five-year survival rate for patients with stage IV metastatic prostate cancer is only approximately 29%. Treatment of metastatic castration-resistant prostate cancer (mCRPC) remains challenging, and no therapeutic options exist for patients who reach this stage of the disease. Therefore, the development of new concepts for effective treatment is urgently needed.

[0003] Once metastatic prostate cancer becomes hormone-resistant, few treatment options remain, and clinical success rates are often quite low. Current medical guidelines typically recommend antimitotic chemotherapy with docetaxel. However, treatment is often associated with severe side effects, and survival rates are only marginally improved. Therefore, early diagnosis and close monitoring for potential recurrence are crucial. Diagnosis of prostate cancer is based on examination of histopathological or cytological samples from the prostate. Existing imaging techniques for therapeutic monitoring of progressing or recurrent prostate cancer, including computed tomography (CT), magnetic resonance (MR) imaging, and ultrasound, are often insufficient for effective disease monitoring and management. As a result, there is a high clinical demand for more effective tools for both the early diagnosis and treatment of prostate cancer.

[0004] It is well known that tumor cells can express unique proteins with altered structures due to mutations or overexpress normal (i.e., non-mutated) proteins that are normally produced in very low amounts in non-malignant cells. Tumor antigens can be broadly classified into two categories based on their expression patterns: tumor-specific antigens (TSAs), which are present only on tumor cells but not on non-malignant cells, and tumor-associated antigens (TAAs), which are present on some tumor cells and non-malignant cells. While TSAs typically result from mutations in proto-oncogenes and tumor suppressors that lead to aberrant protein production, TAA expression is usually caused by mutations in other genes unrelated to tumorigenesis.

[0005] The expression of such proteins on the surface of tumor cells makes it possible to diagnose and characterize the disease by detecting such tumor markers. Proteinaceous binding agents or small molecule drugs bearing a visible label and specifically recognizing such tumor markers are usually used in the diagnosis and imaging of cancer under non-invasive conditions.

[0006] A promising new series of low-molecular-weight contrast agents targets prostate-specific membrane antigen (PSMA). PSMA, also known as folate hydrolase I (FOLH1), is a transmembrane type II glycoprotein of 750 amino acids. The PSMA gene is located on the short arm of chromosome 11 and functions as both a folate hydrolase and a neuropeptidase. It has neuropeptidase function equivalent to that of glutamate carboxypeptidase II (GCPII), referred to as "brain PSMA," and can modulate glutamatergic transmission by cleaving N-acetyl-aspartyl-glutamate (NAAG) into N-acetylaspartate (NAA) and glutamate (NPL 3).

[0007] Prostate-specific membrane antigen (PSMA) is overexpressed in the majority of prostate cancer cases (Non-Patent Documents 4 and 5). Therefore, it has emerged as a promising target for nuclear imaging and radionuclide therapy of mCRPC (Non-Patent Documents 6 to 8). PSMA is (i) primarily restricted to the prostate (it is also detected in small amounts in the neovasculature of many other solid tumors, including bladder, pancreatic, lung, and kidney cancers, but not in normal vasculature), and (ii) abundantly expressed as a protein in all stages of prostate cancer (up to 10 per cancer cell). 6 (iii) it is presented on the cell surface but does not enter the circulation; and (iv) it is associated with enzymatic or signaling activity. Furthermore, PSMA expression is further upregulated in poorly differentiated, androgen-insensitive, or metastatic cancers, and its expression usually correlates with disease progression.

[0008] The unique expression of PSMA makes it an important marker for prostate cancer (and some other cancers). Furthermore, PSMA is a potent extracellular target for imaging agents. Because PSMA is internalized after ligand binding, it is an excellent target for targeted radionuclide therapy (using particle-emitting radionuclides) as well as other therapeutic strategies, such as tumor cell-specific delivery of immunotoxins, immune cell retargeting, prodrug activation, PSMA vaccines, plasmid DNA, and adenoviral immunization. Because of its low expression levels in healthy tissues, PSMA also offers the potential for high-dose therapy with minimal side effects.

[0009] In the past, several PSMA-targeting agents bearing therapeutic or diagnostic moieties have been developed. An FDA-approved radioimmunoconjugate of the anti-PSMA monoclonal antibody (mAb) 7E11, known as PROSTASCINT®, has been used to diagnose prostate cancer metastasis and recurrence. The success of this radiopharmaceutical is limited by the fact that the antibody binds to the intracellular domain of PSMA and can target only dead cells. Furthermore, the use of monoclonal antibodies and antibody fragments as imaging agents is often limited by their slow renal clearance, heterogeneous distribution, poor tumor penetration, and potential immunogenicity.

[0010] To overcome these problems, various small molecule PSMA targeting agents capable of binding to the extracellular domain of PSMA have been developed for PET / CT and SPECT / CT imaging. Examples include radiolabeled N-[N-[(S)-1,3-dicarboxypropyl]carbamoyl]-S-[C]methyl-l-cysteine ​​(DCFBC) and several urea-based peptidomimetic PSMA inhibitors (see Non-Patent Document 9). These include MIP-1095 (Non-Patent Document 10), a PSMA ligand currently under clinical evaluation, and PSMA-617, a DOTA-conjugated PSMA inhibitor developed by Benesova et al. (Non-Patent Document 11 and Patent Document 1), which distributes throughout the body and is rapidly cleared from the blood (Non-Patent Document 12). However, while rapid and systemic access advantageously facilitates tumor targeting and penetration, currently available PSMA-targeting agents carry the risk of mediating nonspecific "off-target" interactions with target-expressing normal tissues and the risk of radiopharmaceutical accumulation in excretory organs (e.g., the kidneys). This can expose non-tumor tissues to radiation doses that ultimately lead to irreversible tissue damage. It has been demonstrated that various radiolabeled small molecule PSMA-targeting agents (including PSMA-617) accumulate in patients' lacrimal and salivary glands and can damage glandular tissues, especially when used in combination with alpha-emitting radionuclides (Non-Patent Documents 13 and 14). One possible solution to this problem involves the use of PSMA-binding agents with high affinity for PSMA (Non-Patent Document 15).

[0011] Recently, various groups have applied the concept of modifying radiopharmaceuticals with albumin conjugates to PSMA-targeting radioligands (Non-Patent Documents 16-19). Indeed, such radioligands exhibit increased blood circulation, 177 Compared with PSMA-conjugated radioligands without albumin conjugates, such as Lu-PSMA-617, it showed increased accumulation and better retention in tumor tissues (Non-Patent Documents 18 and 19). Because the retention of radioactivity in the blood was high, uptake in other organs and tissues, including the kidney, was also poor. 177This was higher than that of PSMA-bound radioligands without albumin conjugates, such as Lu-PSMA-617 (Non-Patent Document 18).

[0012] For example, Non-Patent Document 20 discloses an albumin-conjugated 177 Lu-labeled phosphoramidate-based PSMA inhibitors were evaluated. 177 A DOTA chelator complexing Lu radionuclides was ether-linked to the irreversible PSMA inhibitor CTT1298 (Patent Document 2). However, phosphoramidate-based PSMA binding motives exhibit only low stability at the high temperatures required for coordinated radiolabeling reactions via chelators such as DOTA (high temperatures under prolonged acidic conditions result in hydrolysis of the phosphoramidate PN bond). Therefore, direct radiolabeling reactions cannot be applied, and a multi-step pre-labeling approach must be used. Therefore, as a precursor, 177 Lu-DOTA-azide must be prepared, and then the precursor must be conjugated to the dibenzocyclooctyne-derivatized PSMA motif. Finally, elaborate HPLC purification of the conjugated compound is required, followed by regeneration by evaporation of the HPLC eluent (under N2 atmosphere) and dissolution in physiological media. This procedure may be impossible for clinical use, given the high activity produced. Preclinical biodistribution data indicate poor performance of the radiolabeled agent, particularly with tumor-to-kidney ratios not significantly exceeding 1.

[0013] Another approach was taken by Kelly et al. (Non-Patent Document 17), who evaluated agents that exhibit affinity for both PSMA and human serum albumin (HSA). The ligands developed by Kelly et al. include a p-(iodophenyl)butyric acid derivative for HSA binding and a urea-based PSMA conjugate. The compounds developed by Kelly et al. 131I) is covalently linked to an HSA-binding moiety, which in turn is directly linked to a PSMA conjugate via a hydrocarbyl chain. However, the compounds evaluated are significantly limited in that the radionuclide used is limited to iodine. Furthermore, the compounds evaluated did not demonstrate improved internalization / uptake in target cells.

[0014] The structure (p-iodophenyl)butyric acid was previously found to bind with high affinity to serum albumin (Non-Patent Document 21). It was used to modify rapidly cleared antibody fragments to extend their blood circulation time and improve their pharmacokinetics (Non-Patent Document 22). In the case of folate radioconjugates, modification with this same albumin binder significantly increased tumor uptake and dramatically reduced kidney retention (Non-Patent Document 23 and Non-Patent Document 24).

[0015] The albumin binding properties of these PSMA radioligands were more pronounced than those previously observed with folate radioconjugates, including the same p-iodophenyl-based albumin conjugate. Therefore, it was speculated that weaker binding of PSMA ligands to serum albumin would be beneficial. With regard to radioligand design, this was addressed by replacing the strong albumin binder (p-iodophenyl) butyric acid with (p-tolyl) butyric acid, which has previously been shown to exhibit low albumin binding affinity (Non-Patent Document 21). Therefore, 177 Lu-PSMA-ALB-56, a PSMA-binding radioligand with a p-tolyl moiety as the albumin conjugate instead of the p-iodophenyl-based albumin conjugate, has a p-iodophenyl moiety 177 showed a more favorable tumor-to-background ratio than Lu-PSMA-ALB-53 (Non-Patent Document 19). 177 In the case of Lu-PSMA-ALB-56, the blood radioactivity level was still relatively high, which may indicate that the albumin binding affinity was still too strong.

[0016] This demonstrates the need to balance albumin binding of PSMA-conjugated radioligands to achieve an optimal tissue distribution profile with high tumor uptake and blood radioactivity levels that are not excessively high at the risk of undesirable side effects on healthy tissues.

[0017] Despite many years of progress, prostate cancer remains difficult to diagnose and manage. To enable early detection and treatment of cancer, new diagnostic or imaging agents are needed that can highly selectively target cancer tumor cells and exhibit favorable pharmacokinetic properties for rapid, noninvasive tumor visualization and treatment. [Prior art documents] [Patent documents]

[0018] [Patent Document 1] European Patent Application Publication No. 2862857A1 [Patent Document 2] European Patent Application Publication No. 2970345A1 [Non-patent literature]

[0019] [Non-Patent Document 1] Ferlay, J.; Steliarova-Foucher, E.; Lortet-Tieulent, J.; Rosso, S.; Coebergh, JW; Comber, H.; Forman, D.; Bray, F. Cancer incidence and mortality patterns in Europe: estimates for 40 countries in 2012. Eur J Cancer 2013, 49, (6), 1374-403 [Non-patent document 2] Miller, K. D.; Siegel, R. L.; Lin, C. C.; Mariotto, A. B.; Kramer, J. L.; Rowland, J. H.; Stein, K. D.; Alteri, R.; Jemal, A. Cancer treatment and survivorship statistics, 2016. CA Cancer J Clin 2016, 66, (4), 271-89 [Non-Patent Document 3] Nan, F.; et al. J Med Chem 2000, 43, 772-774 [Non-Patent Document 4] Silver, D. A.; Pellicer, I.; Fair, W. R.; Heston, W. D.; Cordon-Cardo, C. Prostate-specific membrane antigen expression in normal and malignant human tissues. Clin Cancer Res 1997, 3, (1), 81-5 [Non-Patent Document 5] Cunha, A. C.; Weigle, B.; Kiessling, A.; Bachmann, M.; Rieber, E. P. Tissue-specificity of prostate specific antigens: comparative analysis of transcript levels in prostate and non-prostatic tissues. Cancer Lett 2006, 236, (2), 229-38 [Non-Patent Document 6] Bouchelouche, K.; Choyke, PL Prostate-specific membrane antigen positron emission tomography in prostate cancer: a step toward personalized medicine. Curr Opin Oncol 2016, 28, (3), 216-21

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[0020] SUMMARY OF THE INVENTION It is therefore an object of the present invention to overcome the shortcomings of the prior art and to fulfill the need in the art.

[0021] This problem is solved by the subject matter disclosed herein, and more particularly by the subject matter set forth in the appended claims.

[0022] The present invention provides a new class of PSMA-binding radioligands that comprise ibuprofen as an albumin conjugate, a PSMA-binding moiety, and a chelator moiety, thereby forming a trifunctional compound.

[0023] The present invention is described in detail below, but it should be understood that the present invention is not limited to the particular methods, protocols, and reagents described herein, as these may vary. It should also be understood that the terms used herein are not intended to limit the scope of the present invention, which is limited only by the appended claims. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art.

[0024] Elements of the present invention are described below. While these elements are referred to in connection with specific embodiments, it should be understood that they can be combined in any manner and in any number to produce further embodiments. The various described examples and preferred embodiments should not be construed as limiting the invention to only those embodiments explicitly described. This description should be understood to support and encompass embodiments that combine the explicitly described embodiment with any number of the disclosed and / or preferred elements. Furthermore, all permutations and combinations of elements described herein should be considered disclosed by the present description unless the context dictates otherwise.

[0025] In the present invention, different features of the alternatives and embodiments can be combined with each other unless otherwise stated.

[0026] For clarity and readability, the following definitions are provided. The technical features mentioned in these definitions may apply to all embodiments of the present invention. In the context of these embodiments, further definitions and explanations may be specifically provided.

[0027] definition Throughout this specification and the claims that follow, unless otherwise required, the term "comprise" and variations such as "comprises" and "comprising" are understood to mean the inclusion of the specified elements, integers, or steps, but not the exclusion of any other unspecified elements, integers, or steps. The term "consisting of" is a specific embodiment of the term "comprises," in which any other unspecified elements, integers, or steps are excluded. In the present invention, the term "comprising" encompasses the term "consisting of." Thus, the term "comprising" encompasses "including" and "consisting," e.g., a composition "comprising" X may consist solely of X, or may include something additional (e.g., X+Y).

[0028] The terms "a," "an," and "the," and similar references used in describing the present invention (particularly the claims) should be construed to cover both the singular and the plural unless otherwise specified herein or otherwise clearly contradicted by context. The recitation of ranges of values ​​herein is merely intended to serve as a shorthand method of referring individually to each separate value within the range. Unless otherwise specified herein, each separate value is incorporated into the specification as if it were individually recited herein. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.

[0029] The term "substantially" does not exclude "completely", for example, a composition that is "substantially free" of Y may be completely free of Y. Where necessary, the term "substantially" may be omitted from the definition of the invention.

[0030] The term "about" in relation to a numerical value x means x±10%.

[0031] The term "hydrocarbyl" means the residue of a hydrocarbon group, i.e., a hydrocarbon chain radical, preferably independently selected from the group alkyl, alkenyl, alkynyl, aryl, and aralkyl.

[0032] The term "alkyl" includes linear ("straight chain"), branched, and cyclic chain groups having 1 to 30 carbon atoms, preferably 1 to 20, 1 to 15, 1 to 10, 1 to 8, 1 to 6, 1 to 4, 1 to 3, or 1 to 2 carbon atoms. For example, the term "C 1-12"Alkyl" refers to a hydrocarbon group whose carbon chain is straight, branched, or cyclic and contains 1 to 12 carbon atoms. Specific examples of alkyl residues are methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, octyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, icosyl, henicosyl, docosyl, tricosyl, tetracosyl, pentacosyl, hexacosyl, heptacosyl, octacosyl, nonacosyl, or triacosyl, including various branched and / or cyclic isomers thereof, e.g., isobutyl, tert-butyl, or isopentyl. Cyclic alkyl isomers, also referred to herein as "cycloalkyl," refer to saturated alicyclic hydrocarbons containing three ring carbon atoms. "Substituted" linear, branched, and cyclic alkyl groups are also generally encompassed by this term. The term further includes "heteroalkyl," which refers to an alkyl group in which one or more C atoms of the carbon chain are replaced with a heteroatom (e.g., including, but not limited to, N, O, and S). Thus, the term further includes "heterocyclyl" or "heterocycloalkyl," which refer to non-aromatic ring compounds containing three or more ring members in which one or more ring carbon atoms are replaced with a heteroatom (e.g., including, but not limited to, N, O, and S). Heterocyclyl groups encompass unsaturated, partially saturated, and saturated ring systems such as, for example, imidazolyl, imidazolinyl, and imidazolidinyl groups.Heterocyclyl groups include, but are not limited to, aziridinyl, azetidinyl, pyrrolidinyl, imidazolidinyl, pyrazolidinyl, thiazolidinyl, tetrahydrothiophenyl, tetrahydrofuranyl, dioxolyl, furanyl, thiophenyl, pyrrolyl, pyrrolinyl, imidazolyl, imidazolinyl, pyrazolyl, pyrazolinyl, triazolyl, tetrazolyl, oxazolyl, isoxazolyl, thiazolyl, thiazolinyl, isothiazolyl, thiadiazolyl, oxadiazolyl, piperidyl, piperazinyl, morpholinyl, thiomo benzotriazolyl, benzimidazolyl, benzophenone, ... Ranyl, benzothiophenyl, benzothiazolyl, benzoxadiazolyl, benzoxazinyl, benzodithiinyl, benzoxathiinyl, benzothiazinyl, benzoxazolyl, benzothiazolyl, benzothiadiazolyl, benzo[1,3]dioxolyl, pyrazolopyridyl, imidazopyridyl (azabenzimidazolyl), triazolopyridyl, isoxazolopyridyl, purinyl, xanthinyl, adeninyl, guaninyl, quinolinyl, isoquinolinyl, quinolinyl dihydrobenzothiazinyl, dihydrobenzofuranyl, dihydroindolyl, dihydrobenzodioxinyl, tetrahydroindolyl, tetrahydroimidazolyl, tetrahydrobenzimidazolyl, tetrahydrobenzotriazolyl, tetrahydropyrrolopyridyl, tetrahydropyrazolopyridyl, tetrahydroimidazopyridyl, tetrahydrotriazolopyridyl, and tetrahydroquinolinyl groups.Heterocyclyl groups can be substituted or unsubstituted. Representative substituted heterocyclyl groups can be mono- or multiply substituted, for example, but are not limited to, pyridyl or morpholinyl groups that are 2-, 3-, 4-, 5-, or 6-substituted, or disubstituted with various substituents such as those listed above.

[0033] The term "cyclic" includes the term "polycyclic," which refers to structures having multiple ring structures. In particular, the term "cyclic" also refers to spirocyclic structures in which two or more rings share one atom, and 5-fused polycyclic structures in which two or more rings share at least two atoms.

[0034] As used herein, the term "alkenyl" includes linear, branched, and cyclic chain groups containing at least one carbon-carbon double bond, having 2 to 30 carbon atoms, preferably 2 to 20, 2 to 15, 2 to 10, 2 to 8, 2 to 6, 2 to 4, or 2 to 3 carbon atoms. Specific examples of "alkenyl" groups are the various alkene-unsaturated equivalents of those exemplified for alkyl groups, named according to the number and position of the carbon-carbon double bonds using conventions known to those skilled in the art (e.g., butanediylidene, 1-propan-3-ylidene, etc.). An "alkenyl" group preferably contains at least 1, and more preferably at least 2, 3, 4, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or 16 double bonds, with the double bonds preferably located at positions 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, or 29 of the hydrocarbyl chain. Alkenyl groups can be substituted or unsubstituted.

[0035] As used herein, the term "alkynyl" includes straight-chain, branched-chain, and cyclic-chain groups containing at least one carbon-carbon triple bond, having 2 to 30 carbon atoms, preferably 2 to 20, 2 to 15, 2 to 10, 2 to 8, 2 to 6, 2 to 4, or 2 to 3 carbon atoms. Specific examples of "alkynyl" groups are the various alkynically unsaturated equivalents of those exemplified for alkyl and alkenyl groups, named according to the number and position of the carbon-carbon triple bonds according to conventions known to those skilled in the art. An "alkynyl" group preferably contains at least 1, and more preferably at least 2, 3, 4, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or 16 triple bonds, with the double triple bonds preferably located at positions 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 17, 30 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, or 29 of the hydrocarbyl chain. Alkynyl groups can be substituted or unsubstituted.

[0036] The term "aryl" refers to a monocyclic or polycyclic or fused polycyclic aromatic ring system. The term includes monocyclic or polycyclic or fused polycyclic aromatic "heteroaryl" ring systems in which at least one carbon atom of the ring system is replaced with a heteroatom. Typically, the terms "aryl" and "heteroaryl" refer to groups having 3 to 30 carbon atoms, e.g., 3 to 10, especially 2 to 6 carbon atoms.

[0037] The terms "arylalkyl" or "aralkyl" are used interchangeably herein and refer to a group comprising at least one alkyl group and at least one aryl group, as defined herein. In an aralkyl group, as defined herein, the aralkyl group is attached to another moiety of the compound or conjugate of the invention via an alkyl group, exemplified by a benzyl group.

[0038] As used herein, the term "halogen" or "halo" includes fluoro (F), chloro (Cl), bromo (Br), and iodo (I).

[0039] The term "heteroatom" includes N, O, S, and P, preferably N and O.

[0040] The term "substituted" refers to a hydrocarbyl group (e.g., an alkyl or alkenyl group), as defined herein, in which one or more bonds to a hydrogen atom are replaced with a bond to a non-hydrogen or non-carbon atom. Substituted groups also include groups in which one or more bonds to a carbon or hydrogen atom are replaced with one or more bonds (including double or triple bonds) to a heteroatom. Thus, a "substituted" group is substituted with one or more substituents, unless otherwise specified. In some embodiments, a substituted group is substituted with 1, 2, 3, 4, 5, or 6 substituents. Examples of substituents include halogens (i.e., F, Cl, Br, and I); hydroxyl; alkoxy, alkenoxy, alkynoxy, aryloxy, aralkyloxy, heterocyclyloxy, and heterocyclylalkoxy groups; carbonyl (oxo); carboxyl; ester; urethane; oxime; hydroxylamine; alkoxyamine; aralkoxyamine; thiol; sulfide; sulfoxide; sulfone; sulfonyl; sulfonamide; amine; N-oxide; hydrazine; hydrazide; hydrazone; azide; amide; urea; amidine; guanidine; enamine; imide; isocyanate; isothiocyanate; cyanate; thiocyanate; imine; nitro group; nitrile (i.e., CN), haloalkyl, aminoalkyl, hydroxyalkyl, and cycloalkyl.

[0041] compound In a first aspect, the present invention provides a compound represented by general formula (1)(i) or (1)(ii). [ka] wherein A is a diagnostic or therapeutic agent that contains a binding site for a tumor antigen, and the spacer contains at least one C-N bond.

[0042] Thus, the present invention provides plasma protein-bound tumor antigen ligands (particularly plasma protein-bound PSMA ligands) with favorable pharmacokinetic profiles. As used herein, the term "pharmacokinetics" preferably includes the stability, bioavailability, absorption, biodistribution, biological half-life, and / or clearance of a therapeutic or diagnostic agent in a subject.

[0043] In the prior art, albumin conjugates have been used to extend the circulating half-life of conjugates, resulting in compartmentalization of the conjugate in the blood and improved delivery to tumor antigen-expressing (tumor) target cells or tissues, thereby increasing the tumor:non-target ratio relative to normal (non-tumor) organs expressing the tumor antigen. Therefore, without being bound by any theory, it is hypothesized that albumin conjugates impart improved pharmacokinetic properties to conjugates. However, prior art albumin conjugates useful in conjugates can result in significant background signals (and therefore unfavorable tumor-to-background ratios).

[0044] Therefore, the purpose of this study was to replace the previously used albumin binder with another albumin conjugate to find the optimal relationship between albumin binding properties and clearance of the conjugate (and, e.g., its radioactivity) from background tissues and organs. The inventors surprisingly found that ibuprofen, as the albumin conjugate in a tumor antigen-binding radioligand, achieves such a desired balance between plasma protein binding properties and clearance of radioactivity from background tissues and organs. This was particularly surprising. This is because it was previously thought that ibuprofen loses its albumin binding affinity as soon as one attempts to modify the carboxylic acid group of the molecule in order to conjugate it to other moieties of biopharmaceuticals (WO 2008 / 053360 A2; US 2010 / 172844; Dumelin, C.E.; Trussel, S.; Buller, F.; Trachsel, E.; Bootz, F.; Zhang, Y.; Mannocci, L.; Beck, S.C.; Drumea-Mirancea, M.; Seeliger, M.W.; Baltes, C.; Muggler, T.; Kranz, F.; Rudin, M.; Melkko, S.; Scheuermann, J.; Neri, D. A portable albumin binder from a DNA-encoded chemical library. Angew Chem Int Ed Engl 2008, 47, (17), 3196-201). Despite this technical bias, the present inventors have surprisingly found that balanced binding to albumin can be achieved by conjugating ibuprofen via its carboxylic acid group to a diagnostic or therapeutic agent that contains a binding site for a tumor antigen.

[0045] Albumin, particularly human serum albumin (HSA), is the most abundant protein in (human) plasma, constituting approximately half of the serum proteins. As used herein, the term "human serum albumin" or "HSA" preferably refers to the serum albumin protein encoded by the human ALB gene. More preferably, the term refers to UniProt Acc. No. P02768 (Entry Version 240, last modified May 10, 2017), or a functional variant, isoform, fragment, or (post-translationally or otherwise modified) derivative thereof.

[0046] As used herein, diagnostic or therapeutic agent A can be any agent useful in the diagnosis, prevention, or treatment of disease (particularly cancer), as long as it contains a binding site for a tumor antigen.

[0047] Tumor antigens are proteins expressed by tumor cells, and may be structurally altered by mutations, or may be overexpressed normal (i.e., non-mutated) proteins that are normally produced in very small amounts by non-malignant cells. Tumor antigens can be broadly classified into two categories based on their expression patterns: tumor-specific antigens (TSAs), which are present only on tumor cells but not on non-malignant cells, and tumor-associated antigens (TAAs), which are present on some tumor cells and non-malignant cells. TSAs usually result from mutations in proto-oncogenes and tumor suppressors that cause abnormal protein production, while TAA expression is usually caused by mutations in other genes unrelated to tumorigenesis. Preferably, the tumor antigen is prostate-specific membrane antigen (PSMA). Therefore, diagnostic or therapeutic agent A preferably contains a PSMA binding site.

[0048] In addition to the tumor antigen binding site, diagnostic or therapeutic agent A can include (further) components, such as (further) active ingredients (for the diagnosis, prevention, or treatment of a disease such as cancer) and / or one or more linkers. One or more "linkers" or "spacers" can be used to combine various components, such as a tumor antigen conjugate, one or more additional active ingredients, and, optionally, ibuprofen as an albumin conjugate, into a single molecule. For example, a tumor antigen conjugate, such as a PSMA conjugate (e.g., a PSMA conjugate described herein), can be conjugated to a linker described herein. For example, ibuprofen can be conjugated to a spacer described herein.

[0049] Preferably, diagnostic or therapeutic agent A comprises a radiolabel. As used herein, the term "radiolabel" (or radiotracer) refers to a radiolabel, such as a radioactive substance or atom (e.g., a radionuclide). For example, the radiolabel can be a non-metallic radionuclide or a radiometal. 18 F, 11 C. 13 N, 15 O, or 124 Non-metallic radionuclides such as I can be covalently bound to organic molecules, 99m Tc, 67 / 68 Ga, 111 In, or 177 Radioactive metals such as Lu usually need to be coordinated via a so-called "chelator." Therefore, particularly when diagnostic or therapeutic agent A contains a radioactive metal as a radiolabel, it is preferred that diagnostic or therapeutic agent A contain a chelator. The chelator can be conjugated to other components of diagnostic or therapeutic agent A (e.g., tumor antigen binding site and / or ibuprofen) via a linker. For example, diagnostic or therapeutic agent A can contain a radioactive metal coordinated via a chelator. Preferably, the chelator is conjugated to other components of diagnostic or therapeutic agent A (e.g., tumor antigen binding site and / or ibuprofen) via a linker.

[0050] As used herein, the terms "tumor antigen ligand" (e.g., "PSMA ligand"), "compound," and "conjugate" are used interchangeably and refer to the complete molecule (including at least the tumor antigen binding site and ibuprofen, and optionally other components).

[0051] In particular, the tumor antigen ligands (e.g., PSMA ligands) of the present invention (also referred to herein as "conjugates" or "compounds") are covalently connected or linked to each other via a suitable linker or spacer. a first terminal group (e.g., a chelator for coordinating with or to be coordinated with a radiometal); - a second terminal group (ibuprofen as an albumin conjugate), - a third terminal group (a tumor antigen conjugate, such as a PSMA conjugate).

[0052] Therefore, the present invention provides a compound of general formula (1)(a): [ka] wherein D is a chelator; Tbm is the tumor antigen-binding moiety (also called tumor antigen binder); The linker is preferably a linker comprising a cyclic group or an aromatic group, the spacer is a spacer containing a C-N bond, a is an integer selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, preferably 0 or 1. or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0053] In general formula (1)(a), the three terminal groups (ibuprofen, chelator (D), and tumor antigen-binding moiety (Tbm)) are linked via a linker and spacer at the following "branch point" (CH group) as shown in general formula (1)(a). [ka] The position of the "branch point" (CH group) in formula (1)(a) is indicated by the arrow below. [ka]

[0054] The chelator D, the tumor antigen binding moiety Tbm, the linker, and the spacer are preferably defined as described herein.

[0055] The tumor antigen-binding moiety (Tbm) is in particular a PSMA-binding moiety (Pbm).

[0056] Preferably, a is selected from 0, 1, 2, 3, 4, or 5, more preferably 0, 1, or 2, and most preferably a is 0.

[0057] It is specifically envisioned that the structure included within the dashed line in formula (1)(a) below contains at least one peptide bond. [ka] The conjugates of the present invention are ligands that exhibit affinity for both tumor antigens (e.g., PSMA) and HSA. As used herein, the term "ligand" refers to a compound that can interact with (target, bind to) a target (here, HSA or a tumor antigen, e.g., PSMA). The conjugates of the present invention can also be functionally defined as "tumor antigen targeting agents" (e.g., "PSMA targeting agents"). Preferably, "ligands" can selectively bind to their targets. The term "selectively binds" means that a compound binds with higher affinity to its intended target than to another non-target.

[0058] "Binding affinity" is the strength of the binding interaction between a ligand (e.g., a small organic molecule, a protein, or a nucleic acid) and its target / binding partner. Binding affinity is usually measured using the equilibrium dissociation constant (KD ), "off rate" (kO ff ) and "on rate" (kO n ) ratio, which is used to assess and rank the dimensional strength of biomolecular interactions. n ) characterizes how quickly a ligand binds to its target, and the “off-rate” (KO ff ) characterizes how quickly a ligand dissociates from its target. D (KO ff / KO n ) and binding affinity are inversely proportional. Thus, the term "selectively binds" preferably refers to a ligand that binds to its intended target with a K D Lower than D There are many methods to measure binding affinity and dissociation constants, including ELISA, gel shift assays, pull-down assays, equilibrium dialysis, analytical ultracentrifugation, surface plasmon resonance, and spectroscopy.

[0059] In the context of the present invention, the K of binding of a tumor antigen conjugate, such as a PSMA conjugate, to a non-target D is the K of binding of the conjugate or moiety to a tumor antigen, such as human PSMA. D The K of binding of the HSA conjugate to the non-target can be at least 1.5 times, preferably at least 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 750, or 1000 times. D is the K of binding of the conjugate or moiety to HSA D The antibody may be at least 1.5 times, preferably at least 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 750, or 1000 times greater than the antibody.

[0060] In the context of the present invention, the conjugates can bind to tumor antigens (e.g., PSMA) with higher binding affinity than to albumin (HSA). For example, the conjugates can have K in the nanomolar (nM) range. D It can bind to PSMA with a high binding affinity of 1000kJ / μM and to HSA with a moderate affinity in the micromolar range (μM (micromolar)).

[0061] Specifically, it may be preferable to balance the binding affinity of PSMA and HSA to increase tumor uptake while reducing potentially deleterious off-target effects. In particular, the conjugates of the present invention can exhibit higher binding affinity for PSMA than for HSA.

[0062] PSMA binding part The conjugates of the present invention comprise a tumor antigen-binding site (tumor antigen-binding moiety, Tbm), which is preferably a PSMA-binding moiety (also referred to as a "PSMA conjugate"). The PSMA-binding moiety is preferably capable of selectively binding to human PSMA. The term "selectively binds" is defined above.

[0063] The PSMA conjugates can bind reversibly or irreversibly to PSMA, typically with a binding affinity of less than about 100 μM (micromolar).

[0064] Human prostate-specific membrane antigen (PSMA) (also known as glutamic acid carboxypeptidase II (GCPII), folate hydrolase 1, follipoly-gamma-glutamic acid carboxypeptidase (FGCP), and N-acetylated alpha-linked acidic dipeptidase I (NAALADase I)) is a type II transmembrane zinc metallopeptidase that is most highly expressed in the nervous system, prostate, kidney, and small intestine. It is considered a tumor marker for prostate cancer. As used herein, the term "human prostate-specific membrane antigen" or "PSMA" preferably refers to the protein encoded by the human FOLH1 gene. More preferably, the term refers to a protein characterized as UniProt Acc. Q04609 (entry version 186, last modified May 10, 2017), or a functional variant, isoform, fragment, or (post-translationally or otherwise modified) derivative thereof.

[0065] A PSMA conjugate can generally be a conjugate that can selectively (and optionally irreversibly) bind to (human) prostate-specific membrane antigen (see Chang Rev Urol. 2004;6(Suppl 10):S13-S18).

[0066] The PSMA conjugates are preferably selected for their ability to confer selective affinity for PSMA. Preferred PSMA-binding moieties are described in WO 2013 / 022797 A1, WO 2015 / 055318 A1, and EP 2862857 A1, which are incorporated by reference in their entireties.

[0067] Thus, in the conjugates of the invention, the PSMA binding moiety can be characterized by the general formula (3), (3)', (3)'', or (3)'''. [ka] [ka] [ka] [ka] During the ceremony, X and Y are each independently selected from O, N, NH, NH, S, or P; Z is selected from substituted or unsubstituted CH2; R 1 , R 2 , and R 3 are each independently -COH, -CO2H, -SO2H, -SO3H, -SO4H, -PO2H, -PO3H, -PO4H2, -C(O)-(C1-C 10 ) alkyl, -C(O)-O(C1-C 10 ) alkyl, -C(O)-NHR 4 or -C(O)-NR 4 R 5 Selected from R 4 and R 5 are each independently H, a bond, or (C1-C 10 ) alkylene, F, Cl, Br, I, C(O) or —CH(O), C(S) or —CH(S), —C(S)—NH-benzyl-, —C(O)—NH-benzyl, —C(O)—(C-C 10 ) alkylene, -(CH2) p -NH, -(CH2) p -(C1-C 10 ) alkylene, -(CH2) p -NH-C(O)-(CH2) q , -(CH r CH2) t -NH-C(O)-(CH2) p , -(CH2) p -CO-COH, -(CH2) p -CO-CO2H, -(CH2) p -C(O)NH-C[(CH2) q -COH]3, -C[(CH2) p -COH]3, -(CH2) p -C(O)NH-C[(CH2) q -CO2H]3, -C[(CH2) p -CO2H]3, or -(CH2)p -(C5-C 14 ) heteroaryl; f, p, q, r, and t are each independently an integer selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.

[0068] In the general formula (3)', (3)", or (3)'", R 2 (in (3)') or R 3 (In (3)'') is bonded via a double bond. In formula (3)''', X is bonded via a single bond.

[0069] With respect to X and Y, it is understood that, where appropriate, O, N, S, or P can include a hydrogen atom. For example, Y can be O or NH.

[0070] Preferably, f is an integer selected from 1, 2, 3, 4, or 5; more preferably, f is 2 or 3.

[0071] As outlined above, Z is selected from substituted or unsubstituted CH. In other words, Z is selected from CH or substituted CH, where one or both of the hydrogen atoms may be replaced. For example, Z is CH or C=O.

[0072] Preferably, Y is NH and Z is CH2. Thus, the PSMA conjugate can be characterized by the general formula (3)(ii): [ka] [ka] [ka] [ka] During the ceremony, X is selected from O, N or NH or NH2, S, or P; R 1 , R 2 , and R 3 are each independently -COH, -CO2H, -SO2H, -SO3H, -SO4H, -PO2H, -PO3H, -PO4H2, -C(O)-(C1-C 10 ) alkyl, -C(O)-O(C1-C 10 ) alkyl, -C(O)-NHR 4 or -C(O)-NR 4 R 5 Selected from R 4 and R 5 are each independently H, a bond, (C1-C10) alkylene, F, Cl, Br, I, C(O) or —CH(O), C(S) or —CH(S), —C(S)—NH-benzyl-, —C(O)—NH-benzyl, —C(O)—(C1-C 10 ) alkylene, -(CH2) p -NH, -(CH2) p -(C1-C 10 ) alkylene, -(CH2) p -NH-C(O)-(CH2) q , -(CH r CH2) t -NH-C(O)-(CH2) p , -(CH2) p -CO-COH, -(CH2) p -CO-CO2H, -(CH2) p -C(O)NH-C[(CH2) q -COH]3, -C[(CH2) p -COH]3, -(CH2) p -C(O)NH-C[(CH2) q -CO2H]3, -C[(CH2) p -CO2H]3, or -(CH2) p -(C5-C 14 ) heteroaryl; b, p, q, r, and t are each independently an integer selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.

[0073] In the general formula (3)(ii)', (3)(ii)", or (3)(iii)'", R 2 (in (3)(ii)') or R 3 (In (3)(ii)'') is attached via a double bond. In formula (3)(iii)''', X is attached via a single bond.

[0074] In the general formulae (3) and (3)(ii), X is preferably O.

[0075] Furthermore, in the general formulas (3) and (3)(ii), R 1 , R 2 , and R 3 are each independently selected from -COH, -CO2H, -SO2H, -SO3H, -SO4H, -PO2H, -PO3H, and -PO4H2. More preferably, in general formulas (3) and (3)(ii), R 1 , R 2 , and R 3 are -COOH, respectively.

[0076] In the general formula (3)(ii), b is preferably an integer selected from 1, 2, 3, 4, or 5, more preferably 2, 3, or 4, and most preferably 3.

[0077] In general formula (3)(ii), R 1 , R 2 , and R 3 It is also preferred that each of these is COOH, X is O, and b is 3.

[0078] Thus, the PSMA binding moiety is most preferably characterized by formula (3)(a): [ka]

[0079] In another embodiment, the PSMA binding moiety can be characterized by formula (3)(b): [ka]

[0080] In view of the above, the present invention also provides a compound of general formula (1)(d): [ka] (wherein D, spacer, linker, and a are as defined herein in general formula (1)(a) (and preferably embodiments thereof), and X, Y, Z, R 1 , R 2 , R 3 and f are as defined herein in general formula (3) (and preferably in embodiments thereof), or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0081] In particular, the present invention also provides compounds of the general formula (1)(e): [ka] (wherein D, spacer, linker, and a are as defined herein in general formula (1)(a) (and preferably embodiments thereof), and X, R 1 , R 2 , R 3 and b are as defined herein in general formula (3)(ii) (and preferably in embodiments thereof), or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0082] For example, the present invention also provides compounds of the general formula (1)(f): [ka] wherein D, the spacer, the linker, and a are as defined herein in general formula (1)(a) (and preferably in embodiments thereof), or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0083] Linker In the conjugates of the present invention, the tumor antigen-binding moiety (e.g., PSMA conjugate) can be attached / connected to the "branch point" via a suitable linker. Hereinafter, the term "linker" is used specifically to mean the group that connects or links the tumor antigen-binding moiety (e.g., PSMA conjugate) and the -CH- "branch point" to span the distance and / or "space" the tumor antigen-binding moiety (e.g., PSMA conjugate) from the rest of the conjugate.

[0084] The linker preferably avoids steric hindrance between the tumor antigen-binding moiety (e.g., PSMA conjugate) and other groups or entities of the conjugates of the invention, and ensures sufficient mobility and flexibility. Furthermore, the linker preferably can be designed to support and / or enable sufficient HSA binding, high-affinity tumor antigen (e.g., PSMA) binding, and rapid and optionally selective penetration of antigen (e.g., PSMA)-positive cells by internalization of the compounds of the invention.

[0085] In particular, PSMA conjugates, such as those of general formula (3) or (3)(ii), can be preferably linked to the conjugates of the invention via suitable linkers as described in EP 2 862 857 A1. The linkers can preferably confer optimized lipophilic properties to the conjugates of the invention, increasing PSMA binding and cellular uptake and internalization. The linkers can preferably comprise at least one cyclic group and / or at least one aromatic group (particularly groups Q and W of general formula (4) below).

[0086] Thus, in the conjugates of the present invention, preferred linkers can be characterized by general formula (4): [ka] During the ceremony, Each X is independently selected from O, N, S, or P; Q is selected from substituted or unsubstituted alkyl, alkylaryl, and cycloalkyl, preferably substituted or unsubstituted C-C 14 Aryl, C5-C 14 Alkylaryl or C5-C 14 cycloalkyl; W is -(CH2) c -aryl or -(CH2) c -heteroaryl, and c is an integer selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.

[0087] Without wishing to be bound by any theory, it is believed that hydrophilic or polar functional groups in or pendant from the linker (particularly Q, W) can advantageously improve the PSMA binding properties of the conjugates of the invention.

[0088] When Q is a substituted aryl, alkylaryl, or cycloalkyl, exemplary substituents are listed in the "Definitions" section above and include, but are not limited to, halogen (i.e., F, Cl, Br, and I); hydroxyl; alkoxy, alkenoxy, alkynoxy, aryloxy, aralkyloxy, heterocyclyloxy, and heterocyclylalkoxy groups; carbonyl (oxo); carboxyl; ester; urethane; oxime; hydroxylamine; alkoxyamine; aralkoxyamine; thiol; sulfide; sulfoxide; sulfone; sulfonyl; sulfonamide; amine; N-oxide; hydrazine; hydrazide; hydrazone; azide; amide; urea; amidine; guanidine; enamine; imide; isocyanate; isothiocyanate; cyanate; thiocyanate; imine; nitro group; nitrile (i.e., CN), haloalkyl, aminoalkyl, hydroxyalkyl, cycloalkyl.

[0089] Preferably, Q can be selected from substituted or unsubstituted C5-C7 cycloalkyl, more preferably Q is cyclohexyl.

[0090] Preferably, W is —(CH) c -Naphthyl, -(CH2) c -phenyl, -(CH2) c -biphenyl, -(CH2) c -indolyl, -(CH2) c and c is an integer selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. More preferably, W is selected from -(CH)-naphthyl, -(CH)-phenyl, -(CH)-biphenyl, -(CH)-indolyl, or -(CH)-benzothiazolyl. More preferably, W is -(CH)-naphthyl.

[0091] Preferably, each X can be O.

[0092] Thus, a particularly preferred linker connecting a tumor antigen-binding moiety, particularly a PSMA-binding moiety, to a conjugate of the invention can be characterized by the following structural formula (4)(a): [ka]

[0093] In view of the above, the present invention also provides a compound of general formula (1)(g): [ka] wherein D, spacer, and a are as defined herein in general formula (1)(a) (and preferably in its embodiments); and X, Q, and W are as defined herein in general formula (4) (and preferably in its embodiments); or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0094] For example, the present invention also provides compounds of the general formula (1)(h): [ka] wherein D, Tbm, spacer, and a are as defined herein in general formula (1)(a) (and preferably, embodiments thereof), or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0095] In view of the above embodiments relating to specific tumor antigen binding moieties, i.e., PSMA binding moieties, and the above embodiments relating to linkers, the present invention also provides compounds of the general formula (1)(k): [ka] (wherein D, spacer, and a are as defined herein in general formula (1)(a) (and preferably in embodiments thereof), and Y, Z, R 1 , R 2 , R 3and f are as defined herein in general formula (3) (and preferably in embodiments thereof), and X, Q, and W are as defined herein in general formula (4) (and preferably in embodiments thereof), or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0096] In particular, the present invention also provides compounds of the general formula (1)(l): [ka] where D, spacer, and a are as defined herein in general formula (1)(a) (and preferably embodiments thereof), and R 1 , R 2 , R 3 and b are as defined herein in general formula (3)(ii) (and preferably in embodiments thereof), and X, Q, and W are as defined herein in general formula (4) (and preferably in embodiments thereof), or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0097] In particular, the present invention also provides compounds of the general formula (1)(m): [ka] wherein D, spacer, and a are as defined herein in general formula (1)(a) (and preferably in its embodiments); and X, Q, and W are as defined herein in general formula (4) (and preferably in its embodiments); or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0098] For example, the present invention also provides compounds of the general formula (1)(b): [ka] wherein D, the spacer, and a are as defined herein in general formula (1)(a) (and preferably in embodiments thereof), or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0099] Even more specifically, the present invention also relates to compounds of the general formula (1)(c): [ka] wherein D and the spacer are as defined herein in general formula (1)(a) (and preferably in embodiments thereof), or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0100] Spacer In the conjugates of the present invention, ibuprofen (as an albumin conjugate) is conjugated (i.e., covalently bonded or linked) to the -CH- "branch point" via a "spacer." Hereinafter, the term "spacer" is used specifically to mean a group that connects the albumin conjugate and the -CH- "branch point," bridging the distance between them and / or "spaces" these groups from the remaining groups / entities of the conjugate.

[0101] The spacer preferably avoids steric hindrance between ibuprofen (as an albumin conjugate) and other groups or entities of the conjugate of the present invention, and ensures sufficient mobility and flexibility. Furthermore, the spacer preferably can be designed to support and / or enable sufficient HSA binding, high-affinity tumor antigen (e.g., PSMA) binding, and rapid and optionally selective penetration of tumor antigen (e.g., PSMA)-positive cells by internalization of the compound of the present invention.

[0102] The present inventors have determined that the spacer preferably contains at least one C-N bond. A suitable spacer is preferably stable in vivo. The design of the spacer may generally depend on the overall conjugate and is preferably selected to facilitate the functionality of the remaining conjugate (e.g., tumor antigen (e.g., PSMA) binding, PSMA binding, HSA binding, internalization, etc.). Thus, the spacer can be, for example, rigid or flexible, and influence the lipophilicity or hydrophilicity, etc., of the overall conjugate.

[0103] The spacer is a linear or branched, optionally substituted C1-C 20 Hydrocarbyl (e.g., containing up to 5 heteroatoms), more preferably C-C 12 Preferably, the hydrocarbyl may contain at least one heteroatom, optionally up to four or five heteroatoms, preferably selected from N. It preferably contains one or two C-N bonds, more preferably one C-N bond.

[0104] Preferably, the spacer is -[CHR 6 ] u -NR 7 -, wherein R 6 and R 7 are each independently H and a branched, unbranched, or cyclic C-C 12 hydrocarbyl, and u can be an integer selected from 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. More preferably, R 6 and R 7 can be H and u can be an integer selected from 2, 3, or 4, more preferably 2 or 4. Most preferably, R 6 and R 7 can be H, and u can be 2 or 4. The spacer can preferably be —[CH 2 ] 2 —NH— or —[CH 2 ] 4 —NH—.

[0105] Thus, the spacer of the conjugates of the invention can comprise or consist of formula (2)(a) or (2)(a)' or (2)(a)''. [ka]

[0106] Formula (2)(a) reflects a lysine side chain spacer, and is therefore also referred to herein as a "lysine spacer" or "Lys spacer." In the case of formula (2)(a)', k is an integer of 0 to 8, preferably an integer of 2 to 4.

[0107] Exemplary conjugates according to the present invention (e.g., Ibu-PSMA, Ibu-Dα-PSMA, Ibu-Dβ-PSMA, Ibu-N-PSMA, and Ibu-DAB-PSMA, as evaluated in the accompanying Examples) comprise ibuprofen connected to a "branch point" via a spacer comprising or consisting of formula (2)(a):

[0108] Thus, a spacer can comprise at least one amino acid residue or at least one side chain of an amino acid residue. As used herein, the term "amino acid residue" refers to a specific amino acid monomer as a moiety within a spacer.

[0109] An "amino acid" is an organic molecule containing both an acidic (usually carboxy (-COOH)) and an amine (-NH) functional group. One or both of these groups may be derivatized. While the amino and acidic groups can be in any position relative to each other, amino acids typically include 2-aminocarboxylic acids, 3-aminocarboxylic acids, 4-aminocarboxylic acids, etc. The amine group can be attached to the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth (etc.) up to the twentieth carbon atom of the amino acid. In other words, the amino acid can be an alpha, beta, gamma, delta, epsilon (etc.) up to an omega amino acid. Preferably, the acidic group is a carboxy (-COOH) group. However, other acidic groups selected from -OPOH, -POH, -OSOH, or -SOH are also contemplated.

[0110] The amino acid can be a proteinogenic or non-proteinogenic amino acid.

[0111] Proteinogenic amino acids are the 22 amino acids naturally occurring in polypeptides. With the exception of selenocysteine ​​and pyrrolysine, all proteinogenic amino acids (i.e., the remaining 20 proteinogenic amino acids) are encoded by the universal genetic code. The 22 proteinogenic amino acids are arginine, histidine, lysine, aspartic acid, glutamic acid, serine, threonine, asparagine, glutamine, cysteine, glycine, proline, alanine, valine, isoleucine, leucine, methionine, phenylalanine, tyrosine, tryptophan, selenocysteine, and pyrrolysine.

[0112] However, any organic compound with an amine (-NH2) and a carboxylic acid (-COOH) functional group is an amino acid. In light of this, any amino acid other than the 22 proteinogenic amino acids is referred to as a "non-proteinogenic" amino acid. For example, non-proteinogenic amino acids may not be present in proteins (e.g., carnitine, GABA, levothyroxine, 2-aminoisobutyric acid, and the neurotransmitter γ-aminobutyric acid) and may not be produced directly and independently by standard cellular mechanisms (e.g., hydroxyproline and selenomethionine). Non-proteinogenic amino acids may occur, for example, as intermediates in the metabolic pathways of standard amino acids; for example, ornithine and citrulline are produced in the urea cycle. Examples include carnitine, GABA, levothyroxine, 2-aminoisobutyric acid, γ-aminobutyric acid, hydroxyproline, selenomethionine, ornithine, citrulline, diaminobutyric acid, δ-aminolevulinic acid, aminoisobutyric acid, diaminopimelic acid, cystathionine, lanthionine, and djenkolic acid. In the context of the present invention, for example, diaminobutyric acid (DAB) is a particularly preferred non-proteinogenic amino acid.

[0113] The amino acid residues can be derived from naturally occurring amino acids or derivatives thereof. In particular, the amino acid residues can be derived from alpha (α-) amino acids. The amino acids can be (a) D- or L-amino acids.

[0114] For example, the amino acids can be D- or L-enantiomers of amino acids selected from arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and / or valine.

[0115] Preferably, the amino acid is selected from lysine, aspartic acid, asparagine, diaminobutyric acid, phenylalanine, tyrosine, threonine, serine, proline, leucine, isoleucine, valine, arginine, histidine, glutamic acid, glutamine, and alanine. For example, the amino acid can be a D- or L-enantiomer of an amino acid selected from lysine, aspartic acid, asparagine, diaminobutyric acid, phenylalanine, tyrosine, threonine, serine, proline, leucine, isoleucine, valine, arginine, histidine, glutamic acid, glutamine, and alanine. For example, the amino acid is (D- / L-) aspartic acid, glutamic acid, or lysine, such as D-aspartic acid, D-glutamic acid, or L-lysine. For example, the amino acid is (D- / L-) aspartic acid, asparagine, lysine, or diaminobutyric acid. For example, the additional amino acid residue can be aspartic acid, asparagine, or diaminobutyric acid.

[0116] The spacer can contain 1, 2, 3, 4, or 5 amino acid residues, such as one or more D-aspartic acid, one or more D-glutamic acid, and / or one or more L-lysine residues. In conjugates containing D-enantiomers, the use of D-enantiomers can have the advantageous effect of further reducing the metabolic rate and, therefore, clearance from the bloodstream. Preferably, the spacer can contain 1 to 3 (preferably 1 or 2) amino acid residues, such as D-aspartic acid, D-glutamic acid, or (L-)lysine residues, along with another amino acid residue (e.g., aspartic acid, asparagine, or diaminobutyric acid). In other words, the spacer can preferably contain a peptide consisting of 1 to 5 amino acids, more preferably 1 to 3 amino acids, and even more preferably 1 or 2 amino acids.

[0117] Thus, the conjugates of the present invention can include a spacer of formula (2)(b). [ka] During the ceremony, m is an integer selected from 1 or 2; n is an integer selected from 1, 2, 3, 4, or 5, preferably 2 or 3.

[0118] Alternatively, the spacer may be a linear or branched, optionally substituted C-C heteroatom containing at least one N heteroatom. 20 It may include amino acid residues connected to "branch points" through hydrocarbyl groups.

[0119] Thus, the conjugates of the invention can include a spacer of formula (2)(c) or (2)(c)'. [ka] In the formula, o is an integer selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. Preferably, o can be 5.

[0120] In the case of formula (2)(c)′, k is an integer selected from 0 to 8, preferably 2, 3, or 4.

[0121] As mentioned above, the spacer can comprise or consist of an (L-)lysine residue (e.g., as shown in formula (2)(a)). In this context, the spacer can further comprise additional amino acid residues. In particular, the spacer can comprise or consist of formula (2)(d) or (2)(d) or (2)(d)''. [ka] In the formula, A is an amino acid residue, n is an integer selected from 0, 1, 2, 3, 4, or 5, preferably an integer selected from 0 or 1, and k is an integer selected from 0 to 8, preferably an integer selected from 2 to 4.

[0122] In formula (2)(d), A can be any amino acid residue described above, particularly with respect to various preferred amino acids. For example, the additional amino acid residue can be aspartic acid, asparagine, or diaminobutyric acid.

[0123] For example, the spacer can comprise or consist of formula (2)(d)(i) or (2)(d)(i)'. [ka] In the formula, k is an integer selected from 0 to 8, preferably an integer of 2 to 4.

[0124] For example, the spacer can comprise or consist of formula (2)(d)(ii) or (2)(d)(ii)'. [ka] In the formula, k is an integer selected from 0 to 8, preferably an integer selected from 2 to 4.

[0125] For example, the spacer can comprise or consist of formula (2)(d)(iii) or (2)(d)(iii)'. [ka] [ka] In the formula, k is an integer selected from 0 to 8, preferably an integer selected from 2 to 4.

[0126] For example, the spacer can comprise or consist of formula (2)(d)(iv) or (2)(d)(iv)'. [ka] In the formula, k is an integer selected from 0 to 8, preferably an integer selected from 2 to 4.

[0127] In view of the above, the present invention also provides a compound of general formula (1)(n): [ka] wherein D is a chelator (e.g., a chelator described herein); A is an amino acid residue (e.g., an amino acid residue described herein) or an amino acid residue side chain thereof; V is a single bond, N or NH, or an optionally substituted C-C group containing up to three heteroatoms. 12 hydrocarbyl, said heteroatoms being preferably selected from N, a is an integer selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 (e.g., an integer described herein); and n is an integer selected from 0, 1, 2, 3, 4, or 5, preferably an integer selected from 0 or 1.

[0128] Therefore, the present invention also provides compounds of the general formula (1)(o): [ka] wherein D is a chelator (e.g., a chelator described herein); A is an amino acid residue (e.g., an amino acid residue described herein) or an amino acid residue side chain thereof; V is a single bond, N or NH, or an optionally substituted C-C group containing up to three heteroatoms. 12 hydrocarbyl, said heteroatoms being preferably selected from N, and n is an integer selected from 0, 1, 2, 3, 4, or 5, preferably an integer selected from 0 or 1.

[0129] V in formula (1)(n) or 1(o) can contain one or two C-N bonds, preferably one C-N bond.

[0130] V can represent an NH group in both formula (1)(n) or (1)(o).

[0131] In particular, the present invention also provides compounds of formula (6)(a) or (6)(a)': [ka] wherein D, the linker, and a are as defined herein in general formula (1)(a) (and preferably embodiments thereof); X, Y, Z, R 1 , R 2 , R 3 and f are as defined herein in general formula (3) (and preferably in embodiments thereof), A is an amino acid residue (e.g., an amino acid residue described herein); n is an integer selected from 0, 1, 2, 3, 4, or 5, preferably 0 or 1; and k is an integer selected from 0, 1, 2, 3, 4, 5, 6, 7, or 8, preferably an integer selected from 2, 3, or 4, or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0132] In particular, the present invention also provides compounds of formula (6)(b) or (6)(b)': [ka] wherein D, the linker, and a are as defined herein in general formula (1)(a) (and preferably embodiments thereof); X, R 1 , R 2 , R 3 and b are as defined herein in general formula (3)(ii) (and preferably embodiments thereof), A is an amino acid residue (e.g., an amino acid residue described herein); n is an integer selected from 0, 1, 2, 3, 4, or 5, preferably 0 or 1; and k is an integer selected from 0, 1, 2, 3, 4, 5, 6, 7, or 8, preferably an integer selected from 2, 3, or 4, or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0133] In particular, the present invention also provides compounds of formula (6)(c) or (6)(c)': [ka] wherein D, the linker, and a are as defined herein in general formula (1)(a) (and preferably embodiments thereof); A is an amino acid residue (e.g., an amino acid residue described herein); n is an integer selected from 0, 1, 2, 3, 4, or 5, preferably 0 or 1; and k is an integer selected from 0, 1, 2, 3, 4, 5, 6, 7, or 8, preferably an integer selected from 2, 3, or 4, or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0134] In particular, the present invention also provides compounds of formula (6)(d) or (6)(d)': [ka] wherein D, Tbm, and a are as defined herein in general formula (1)(a) (and preferably embodiments thereof); X, Q, and W are as defined herein in general formula (4) (and preferably embodiments thereof); A is an amino acid residue (e.g., an amino acid residue described herein); n is an integer selected from 0, 1, 2, 3, 4, or 5, preferably 0 or 1; and k is an integer selected from 0, 1, 2, 3, 4, 5, 6, 7, or 8, preferably an integer selected from 2, 3, or 4, or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0135] In particular, the present invention also provides compounds of formula (6)(e) or (6)(e)': [ka] wherein D, Tbm, and a are as defined herein in general formula (1)(a) (and preferably embodiments thereof); A is an amino acid residue (e.g., an amino acid residue described herein); n is an integer selected from 0, 1, 2, 3, 4, or 5, preferably 0 or 1; and k is an integer selected from 0, 1, 2, 3, 4, 5, 6, 7, or 8, preferably an integer selected from 2, 3, or 4, or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0136] In particular, the present invention also provides compounds of formula (6)(f) or (6)(f)': [ka] wherein D and Tbm are as defined herein in general formula (1)(a) (and preferably in embodiments thereof); A is an amino acid residue (e.g., an amino acid residue described herein); n is an integer selected from 0, 1, 2, 3, 4, or 5, preferably 0 or 1; and k is an integer selected from 0, 1, 2, 3, 4, 5, 6, 7, or 8, preferably an integer selected from 2, 3, or 4, or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0137] In particular, the present invention also provides compounds of formula (6)(g) or (6)(g)': [ka] wherein D and a are as defined herein in general formula (1)(a) (and preferably embodiments thereof); Y, Z, R 1 , R 2 , R 3 and f are as defined herein in general formula (3) (and preferably in embodiments thereof), X, Q, and W are as defined herein in general formula (4) (and preferably embodiments thereof); A is an amino acid residue (e.g., an amino acid residue described herein); n is an integer selected from 0, 1, 2, 3, 4, or 5, preferably 0 or 1; and k is an integer selected from 0, 1, 2, 3, 4, 5, 6, 7, or 8, preferably an integer selected from 2, 3, or 4, or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0138] In particular, the present invention also provides compounds of formula (6)(h) or (6)(h)': [ka] [ka] wherein D and a are as defined herein in general formula (1)(a) (and preferably embodiments thereof); R 1 , R 2 , R3 and b are as defined herein in general formula (3)(ii) (and preferably embodiments thereof), X, Q, and W are as defined herein in general formula (4) (and preferably embodiments thereof); A is an amino acid residue (e.g., an amino acid residue described herein); n is an integer selected from 0, 1, 2, 3, 4, or 5, preferably 0 or 1; and k is an integer selected from 0, 1, 2, 3, 4, 5, 6, 7, or 8, preferably an integer selected from 2, 3, or 4, or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0139] In particular, the present invention also provides compounds of formula (6)(i) or (6)(i)': [ka] wherein D and a are as defined herein in general formula (1)(a) (and preferably embodiments thereof); X, Q, and W are as defined herein in general formula (4) (and preferably embodiments thereof); A is an amino acid residue (e.g., an amino acid residue described herein); n is an integer selected from 0, 1, 2, 3, 4, or 5, preferably 0 or 1; and k is an integer selected from 0, 1, 2, 3, 4, 5, 6, 7, or 8, preferably an integer selected from 2, 3, or 4, or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0140] In particular, the present invention also provides compounds of formula (6)(j) or (6)(j)': [ka] wherein D is a chelator as described herein; X, Q, and W are as defined herein in general formula (4) (and preferably embodiments thereof); A is an amino acid residue (e.g., an amino acid residue described herein); n is an integer selected from 0, 1, 2, 3, 4, or 5, preferably 0 or 1; and k is an integer selected from 0, 1, 2, 3, 4, 5, 6, 7, or 8, preferably an integer selected from 2, 3, or 4, or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0141] The most preferred amino acid residues in the context of formulas (6)(a) to (6)(j) are aspartic acid, asparagine, and diaminobutyric acid, or -[A] n does not exist.

[0142] For example, the present invention also provides compounds of formula (7)(a) or (7)(a)': [ka] or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof, wherein D is a chelator as described herein.

[0143] For example, the present invention also provides compounds of formula (7)(b) or (7)(b)': [ka] [ka] or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof, wherein D is a chelator as described herein.

[0144] For example, the present invention also provides compounds of formula (7)(c) or (7)(c)': [ka] or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof, wherein D is a chelator as described herein.

[0145] For example, the present invention also provides compounds of formula (7)(d) or (7)(d)': [ka] or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof, wherein D is a chelator as described herein.

[0146] For example, the present invention also provides compounds of formula (7)(e) or (7)(e)': [ka] or a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex thereof, wherein D is a chelator as described herein.

[0147] In any of the foregoing formulas (7)(a), (7)(a)', (7)(b), (7)(b)', (7)(c), (7)(c)', (7)(d), (7)(d)', (7)(e), and (7)(e)', the lysine side chain as a spacer or part of a spacer consists of two or four methylene groups linking the branch point to the ibuprofen group through the lysine side chain NH group. Alternatively, compounds of these formulas can have 0, 1, 3, 5, 6, 7, or 8 methylene groups.

[0148] Chelator The conjugates of the invention can further comprise a chelator, for example, a chelator that can be useful for coordinating a radiometal, such as to provide a radiolabeled conjugate (also referred to as a "radioligand").

[0149] The terms "chelator" or "chelating moiety" are used interchangeably herein to refer to a multidentate (multiple-bond) ligand that can form two or more separate coordinate bonds with a central (metal) ion. Specifically, such molecules, or molecules that share one electron pair, are also referred to as "Lewis bases." The central (metal) ion is typically coordinated to the chelator by two or more electron pairs. The terms "bidentate chelator," "tridentate chelator," and "tetradentate chelator" are art-recognized and refer to chelators that have two, three, and four electron pairs, respectively, readily available for simultaneous donation to the metal ion coordinated by the chelator. Typically, the electron pairs of a chelator form coordinate bonds with a single central (metal) ion; however, in certain instances, chelators can form coordinate bonds with multiple metal ions, allowing for a variety of binding modes.

[0150] The terms "coordinate" and "coordination" refer to the interaction in which one multi-electron pair donor coordinates with one central (metal) ion, i.e., shares ("coordinates") two or more unshared electron pairs.

[0151] Chelating agents are preferably selected based on their ability to coordinate with a desired central (metal) ion, such as a radionuclide, as described herein.

[0152] Thus, the chelator D can be characterized by one of the following formulae (5a) to (5jj): [ka] [ka] [ka] [ka]

[0153] The chelator (D) can be selected from any one of the chelators (5a) to (5jj) above.

[0154] Preferably, the chelator (D) is 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), N,N"-bis[2-hydroxy-5-(carboxyethyl)-benzyl]ethylenediamine-N,N"-diacetic acid (HBED-CC), 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA), 2-(4,7-bis(carboxymethyl)-1,4,7-triazonan-1-yl)pentanedioic acid (NODAGA), [2-(4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododecan-1-yl)-pentanedioic acid (DOTAGA), 1,4,7-triazacyclononanephosphine acid (TRAP), 1,4,7-triazacyclononane-1-[methyl(2-carboxyethyl)-phosphinic acid]-4,7-bis[methyl(2-hydroxymethyl)phosphinic acid] (NOPO), 3,6,9,15-tetraazabicyclo[9,3,1]pentadeca-1(15),11,13-triene-3,6,9-triacetic acid (PCTA), N'-{5-[acetyl(hydroxy)amino]pentyl}-N-[5-({4-[(5-aminopentyl)(hydroxy)amino]-4-oxobutanoyl}amino)pentyl]-N-hydroxysuccinamide (DFO), and diethylenetriaminepentaacetic acid (DTPA), or a derivative thereof.

[0155] More preferably, the chelator can be DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid, which can be characterized by formula (5a)), NODAGA (2-(4,7-bis(carboxymethyl)-1,4,7-triazonan-1-yl)-pentanedioic acid, which can be characterized by formula (5c)), or a derivative thereof. In some embodiments, the chelator can be NODAGA.

[0156] For example, the chelator can be DOTA. Advantageously, DOTA is useful in diagnostic (e.g., 68 Ga) and therapeutic (e.g. 90 Y or 177 DO3AP (which can be characterized by the formula (5hh)), DO3AP, effectively complexes with (Lu) radionuclides, allowing the use of the same conjugate for both imaging and therapeutic purposes, i.e., as a therapeutic diagnostic agent. PrA (which can be characterized by formula (5ii)), or DO3AP ABn Scandium radionuclides (e.g., 5jj), such as 43 Sc, 44 Sc, 47 DOTA derivatives capable of complexing Sc may also be preferred and are described in Kerdjoudj et al. Dalton Trans., 2016, 45, 1398-1409.

[0157] Other preferred chelators in the context of the present invention include N,N"-bis[2-hydroxy-5-(carboxyethyl)benzyl]ethylenediamine-N,N"-diacetic acid (HBED-CC), 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA), 2-(4,7,10-tris(carboxymethyl)-1,4,7,10-tetra-azacyclododecan-1-yl)-pentanedioic acid (DOTAGA), 1,4,7-triazacyclononanephosphinic acid (TRAP), 1,4,7-triazacyclononane-1-[methyl(2-carboxyethyl)benzyl]ethylenediamine-N,N"-diacetic acid N'-{5-[acetyl(hydroxy)amino]-pentyl}-N-[5-({4-[(5-aminopentyl)(hydroxy)amino]-4-oxobutanoyl}-amino)pentyl]-N-hydroxysuccinamide (DFO), and diethylene-triaminepentaacetic acid (DTPA).

[0158] The chelator group, e.g., DOTA group, can be complexed with a central (metal) ion, particularly a radionuclide as defined herein. Alternatively, the chelator group, e.g., DOTA, can be uncomplexed with a central (metal) ion, particularly a radionuclide as defined herein, and can exist in an uncomplexed form. When the chelator (e.g., DOTA) is not complexed with the metal ion, the carboxylic acid group of the chelator can be in the free acid form or in the form of a salt.

[0159] Below, specific exemplary conjugates according to the invention are described, which are particularly preferred.

[0160] A preferred exemplary conjugate according to the present invention has the formula (8)(a) or (8)(a)': [ka] (Formula (8)(a) is also referred to as "Ibu-PSMA") or a pharmacologically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0161] Another preferred exemplary conjugate according to the present invention has the formula (8)(b) or (8)(b)': [ka] ((Formula (8)(b) is also referred to as "Ibu-Dα-PSMA") or a pharmacologically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0162] Another preferred exemplary conjugate according to the present invention has formula (8)(c) or (8)(c)': [ka] (Formula (8)(c) is also referred to as "Ibu-Dβ-PSMA") or a pharmacologically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0163] Another preferred exemplary conjugate according to the present invention has formula (8)(d) or (8)(d)': [ka] (Formula (8)(d) is also referred to as "Ibu-N-PSMA") or a pharmacologically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0164] Another preferred exemplary conjugate according to the present invention has formula (8)(e) or (8)(e)': [ka] (Formula (8)(e) is also referred to as "Ibu-DAB-PSMA") or a pharmacologically acceptable salt, ester, solvate, or radiolabeled complex thereof.

[0165] Formulas (8)(a), (8)(a)′, (8)(b), (8)(b)′, (8)(c), (8)(c)′, (8)(d), (8)(d)′, (8)(e), and (8)(e)′ are all disclosed as containing 0, 1, 3, 5, 6, 7, or 8 —[CH] moieties connecting the lysine side chain NH groups of the spacer to the branch points, instead of the 2 and 4 methylene groups defined in the formulas above.

[0166] pharmaceutically acceptable salts The present invention further includes pharmaceutically acceptable salts of the conjugates (compounds) described herein.

[0167] The preparation of pharmaceutical compositions is well known to those skilled in the art. Pharmaceutically acceptable salts of the conjugates of the present invention can be prepared by conventional procedures, such as by reacting any free base and / or acid of the conjugate according to the present invention with at least a stoichiometric amount of the desired salt-forming acid or base, respectively.

[0168] Pharmaceutically acceptable salts of the present invention include salts with inorganic cations such as sodium, potassium, calcium, magnesium, zinc, and ammonium, as well as salts with organic bases. Suitable organic bases include N-methyl-D-glucamine, argmme, benzathine, diolamine, olamine, procam, and tromethamine. Pharmaceutically acceptable salts of the present invention also include salts derived from organic or inorganic acids. Suitable anions include acetate, adipate, besylate, bromide, camsylate, chloride, citrate, edisylate, estolate, fumarate, gluceptate, gluconate, glucuronate, hippurate, hyclate, hydrobromide, hydrochloride, iodide, isethionate, lactate, lactobionate, maleate, mesylate, methyl bromide, methyl sulfate, napsylate, nitrate, oleate, pamoate, phosphate, polygalacturonate, stearate, succinate, sulfate, sulfosalicylate, tannate, tartrate, terephthalate, tosylate, and triethiodide.

[0169] Complexed / uncomplexed forms The present invention further includes conjugates (compounds) described herein in which the chelator (D) may or may not be complexed with a metal ion (such as a radionuclide).

[0170] The term "radionuclide" (or "radioisotope") means a natural or artificial isotope with an unstable neutron to proton ratio that decays with the emission of corpuscular (i.e., protons (alpha rays) or electrons (beta rays) or electromagnetic radiation (gamma rays). In other words, a radionuclide undergoes radioactive decay. The chelator (D) is capable of forming a complex with a known radionuclide. Preferably, a radionuclide useful for cancer imaging or therapy is suitable. Such radionuclides include, but are not limited to, 94 Tc, 99m Tc, 90 In, 111 In, 67 Ga, 68 Ga, 86 Y, 90 Y, 177 Lu, 151 Tb, 186 Re, 188 Re, 64 Cu, 67 Cu, 55 Co, 57 Co, 43 Sc, 44 Sc, 47 Sc, 225 Ac, 213 Bi, 212 Bi, 212 Pb, 227 Th, 153 Sm, 166 Ho, 152 Gd, 153 Gd, 157 Gd, or 166Dy. The selection of a suitable radionuclide depends, inter alia, on the chemical structure and chelating ability of the chelator (D) and the application of the resulting (complexed) conjugate (e.g., diagnostic vs. therapeutic). On the other hand, the chelator (D) can be selected taking into account the envisaged radionuclide / radiometal. For example, 90 Y, 131 I, 161 Tb, 177 Beta emitters such as Lu can be used for simultaneous systemic radionuclide therapy. When DOTA is used as a chelator, 68 Ga, 43、44、47 Sc, 177 Lu, 161 Tb, 225 Ac, 213 Bi, 212 Bi, 212 The use of either Pb can be advantageously enabled.

[0171] In some preferred embodiments, the radionuclide is 177 In some preferred embodiments, the radionuclide is 44 In some preferred embodiments, the radionuclide is 64 In some preferred embodiments, the radionuclide is 68 Most preferably, the radionuclide is 177 This is Lu.

[0172] It is within the skill and knowledge of one of ordinary skill in the art to select an appropriate combination of conjugate (compound) and radionuclide. For example, in some preferred embodiments, the chelator can be DOTA and the radionuclide can be 177 In another preferred embodiment, the chelator can be DOTA and the radionuclide can be Lu. 68 In another preferred embodiment, the chelator can be DOTA and the radionuclide can be Ga. 44 In a more preferred embodiment, the chelator can be DOTA and the radionuclide can be Sc.64 In another preferred embodiment, the chelator can be NODAGA and the radionuclide can be Cu. 64 It can be Cu.

[0173] Esters and Prodrugs The present invention further encompasses the conjugates of the present invention in their esterified form, particularly where the free carboxylic acid group is esterified. Such esterified compounds may be the product form of the conjugates (compounds) of the present invention. Suitable ester prodrugs include saturated and unsaturated C8-C 18 Contains various alkyl esters of fatty acids.

[0174] Enantiomers The conjugates (compounds) disclosed herein may exist in particular geometric or stereoisomeric forms. Furthermore, the compounds may be optically active. The conjugates of the present invention may also include cis- and trans-isomers, R- and S-enantiomers, diastereomers, (D)-isomers, (L)-isomers, racemic mixtures thereof, and other mixtures thereof. Additional asymmetric carbon atoms may be present in a substituent, such as an alkyl group. For example, if a specific enantiomer of a group or conjugate is desired, it can be prepared by asymmetric synthesis or by derivatization with a chiral auxiliary, the resulting diastereomeric mixture separated, and the auxiliary cleaved to yield the pure desired enantiomer. Alternatively, if the group or conjugate contains a basic functional group, such as amino, or an acidic functional group, such as carboxyl, diastereomeric salts can be formed with an appropriate optically active acid or base, followed by separation of the formed diastereomers by fractional crystallization or chromatographic means well known in the art, followed by recovery of the pure enantiomers.

[0175] A "stereoisomer" is one stereoisomer of a compound that is substantially free of other stereoisomers of that compound. Thus, a stereoisomerically pure compound having one chiral center is substantially free of the opposite enantiomer of that compound. A stereoisomerically pure compound having two chiral centers is substantially free of other diastereomers of that compound. A typical stereoisomerically pure compound contains greater than about 80% by weight of one stereoisomer of the compound and less than about 20% by weight of other stereoisomers of the compound, e.g., greater than about 90% by weight of one stereoisomer of the compound and less than about 10% by weight of other stereoisomers of the compound, or greater than about 95% by weight of one stereoisomer of the compound and less than about 5% by weight of other stereoisomers of the compound, or greater than about 97% by weight of one stereoisomer of the compound and less than about 3% by weight of other stereoisomers of the compound.

[0176] Thus, any formula disclosed herein includes its enantiomers and / or stereoisomers.

[0177] Radiolabeled complexes In a further aspect, the present invention relates to the use of the conjugate (compound) of the present invention for the preparation of a radiolabeled complex or as a pharmaceutical or as a precursor of a pharmaceutical. Such a radiolabeled complex preferably comprises a conjugate (compound) according to the present invention and a radionuclide. The chelator (D) preferably coordinates to the radionuclide to form the radiolabeled complex. Suitable radionuclides can be selected from, but are not limited to, therapeutic and diagnostic metal isotopes. 94 Tc, 99m Tc, 90 In, 111 In, 67 Ga, 68 Ga, 86 Y, 90 Y, 177 Lu, 151 Tb, 186 Re, 188 Re, 64 Cu, 67 Cu, 55 Co, 57 Co,43 Sc, 44 Sc, 47 Sc, 225 Ac, 213 Bi, 212 Bi, 212 Pb, 227 Th, 153 Sm, 166 Ho, 152 Gd, 153 Gd, 157 Gd, or 166 Contains Dy.

[0178] According to a further aspect, the present invention also provides a complex comprising a radionuclide (preferably a radionuclide as described herein) and a conjugate according to the present invention.

[0179] Pharmaceutical Composition According to a further aspect, the present invention also provides pharmaceutical compositions comprising a conjugate (compound) of the invention (including a pharmaceutically acceptable salt, ester, solvate, or radiolabeled complex as described herein), and a pharmaceutically acceptable carrier and / or excipient.

[0180] The term "pharmaceutically acceptable" refers to a compound or agent that is compatible with the conjugate of the present invention and does not interfere with and / or substantially reduce its diagnostic or therapeutic activity. Pharmaceutically acceptable carriers preferably have sufficiently high purity and sufficiently low toxicity to render them suitable for administration to a subject to be treated.

[0181] Formulations, Carriers, and Excipients Pharmaceutically acceptable excipients can serve a variety of functional roles, including, but not limited to, diluents, fillers, bulking agents, carriers, disintegrants, binders, lubricants, glidants, coatings, solvents and co-solvents, buffers, preservatives, adjuvants, antioxidants, humectants, antifoaming agents, thickeners, sweeteners, flavorings, and humectants.

[0182] Suitable pharmaceutically acceptable excipients are typically selected based on the formulation of the (pharmaceutical) composition.

[0183] For (pharmaceutical) compositions in liquid form, generally useful pharmaceutically acceptable excipients include solvents, diluents or carriers such as (pyrogen-free) water, (isotonic) saline solutions such as phosphate or citrate buffered saline, fixed oils, vegetable oils (e.g., peanut oil, cottonseed oil, sesame oil, olive oil, corn oil), ethanol, polyols (e.g., glycerol, propylene glycol, polyethylene glycol, etc.); lecithin; surfactants; preservatives such as benzyl alcohol, parabens, chlorobutanol, phenol, ascorbic acid, thimerosal; isotonic agents such as sugars, polyalcohols such as mannitol, sorbitol, or sodium chloride; aluminum monostearate or gelatin; ascorbic acid or Examples of suitable reference media include antioxidants such as sodium bisulfite; chelating agents such as ethylenediaminetetraacetic acid (EDTA); buffers such as acetate, citrate, or phosphate; and tonicity adjusters such as sodium chloride or dextrose. pH can be adjusted with acids or bases such as hydrochloric acid or sodium hydroxide. The buffer can be hypertonic, isotonic, or hypotonic with respect to a particular reference medium; i.e., the buffer can have a higher, the same, or lower salt content than the particular reference medium; preferably, the salt can be used at a concentration that does not result in cell damage due to osmotic or other concentration effects. Reference media can be, for example, fluids occurring in in vivo methods, such as blood, lymph, cytosolic fluid, or other body fluids, or fluids that can be used as reference media in in vitro methods, such as common buffers or fluids. Such common buffers or fluids are known to those skilled in the art.

[0184] Liquid (pharmaceutical) compositions administered by injection, particularly iv injection, should preferably be sterile and stable under the conditions of manufacture and storage. Such compositions are typically formulated as parenterally acceptable aqueous solutions that are pyrogen-free, have a suitable pH, are isotonic, and maintain the stability of the active ingredient.

[0185] For liquid pharmaceutical compositions, suitable pharmaceutically acceptable excipients and carriers include water, typically pyrogen-free water; isotonic saline or buffered (aqueous) solutions, such as phosphate, citrate, etc. In particular, for injection of the (pharmaceutical) composition of the present invention, water or preferably a buffer, more preferably an aqueous buffer, can be used, which may contain a sodium salt, such as at least 50 mM of a sodium salt, a calcium salt, such as at least 0.01 mM of a calcium salt, and optionally a potassium salt, such as at least 3 mM of a potassium salt.

[0186] The sodium salts, calcium salts, and optionally potassium salts may be present in the form of their halides (e.g., chloride, iodide, or bromide), their hydroxides, carbonates, bicarbonates, or sulfates. Non-limiting examples of sodium salts include, for example, NaCl, NaI, NaBr, Na2CO3, NaHCO3, and Na2SO4; examples of optional potassium salts include, for example, KCl, KI, KBr, K2CO3, KHCO3, and K2SO4; and examples of calcium salts include, for example, CaCl2, CaI2, CaBr2, CaCO3, CaSO4, and Ca(OH)2. Additionally, organic anions of the above cations may also be contained in the buffer.

[0187] A buffer suitable for injection purposes as defined above can contain a salt selected from sodium chloride (NaCl), calcium chloride (CaCl), and optionally potassium chloride (KCl), and additional anions may be present in addition to the chloride. CaCl can also be replaced with other salts, such as KCl. Typically, the salts in an injection buffer are present in concentrations of at least 50 mM sodium chloride (NaCl), at least 3 mM potassium chloride (KCl), and at least 0.01 mM calcium chloride (CaCl). An injection buffer can be hypertonic, isotonic, or hypotonic with respect to a specific reference medium, i.e., the buffer can have a higher, the same, or lower salt content with respect to a specific reference medium. Preferably, the salts can be used at concentrations that do not cause cell damage due to osmotic or other concentration effects.

[0188] For (pharmaceutical) compositions in (semi)solid form, suitable pharmaceutically acceptable excipients and carriers include binders such as microcrystalline cellulose, gum tragacanth or gelatin; starch or lactose; sugars such as, for example, lactose, glucose and sucrose; starches such as, for example, corn starch or potato starch; cellulose and its derivatives, for example, sodium carboxymethylcellulose, ethylcellulose, cellulose acetate, etc.; disintegrating agents such as alginic acid; lubricants such as magnesium stearate; glidants such as stearic acid, magnesium stearate; calcium sulfate, colloidal silicon dioxide, etc.; sweetening agents such as sucrose or saccharin; flavoring agents such as peppermint, methyl salicylate, or orange flavoring, etc.

[0189] Generally, (pharmaceutical) compositions for topical administration can be formulated as creams, ointments, gels, pastes, or powders. (Pharmaceutical) compositions for oral administration can be formulated as tablets, capsules, liquids, powders, or sustained-release forms. However, according to a preferred embodiment, the (pharmaceutical) compositions of the present invention are administered parenterally, particularly via intravenous or intratumoral injection, and are therefore formulated in liquid or lyophilized form for parenteral administration as described elsewhere herein. Parenteral formulations are typically stored in vials, IV bags, ampoules, cartridges, or pre-filled syringes, and can be administered as injections, inhalants, or aerosols, with injections being preferred.

[0190] The (pharmaceutical) composition may be provided in lyophilized form, which is reconstituted in a suitable buffer, advantageously based on an aqueous carrier, prior to administration.

[0191] The (pharmaceutical) composition preferably comprises a safe and effective amount of the conjugate or radiolabeled complex of the present invention.

[0192] As used herein, a "safe and effective amount" refers to an amount of an active agent sufficient to allow diagnosis and / or significantly induce positive changes in the disease to be treated or prevented. At the same time, however, a "safe and effective amount" is small enough to avoid serious side effects, i.e., to provide a good relationship between benefit and risk. A "safe and effective amount" will also vary depending on the specific condition to be diagnosed or treated, as well as the age and physical condition of the patient to be treated, the severity of the condition, the duration of treatment, the nature of any accompanying treatments, the nature of the particular pharmaceutically acceptable excipients or carriers used, and similar factors.

[0193] The conjugates (compounds) of the present invention are also preferably provided for use in the treatment of cancer or in the preparation of a medicament for the treatment of cancer, in particular the treatment and / or prevention of prostate, pancreatic, renal or bladder cancer.

[0194] kit According to a further aspect, the present invention also provides kits comprising the conjugates of the invention (including pharmaceutically acceptable salts, esters, solvates, or radiolabeled complexes thereof) and / or pharmaceutical compositions of the invention.

[0195] Optionally, the kit may include at least one additional agent as defined herein in the context of a pharmaceutical composition, such as a radionuclide, an antimicrobial agent, a solubilizing agent, etc.

[0196] The kit may be a kit including two or more parts containing the above-exemplified components in suitable containers. For example, each container may be a vial, bottle, squeeze bottle, jar, sealed sleeve, envelope or pouch, tube or blister package, or other suitable form, as long as the container preferably prevents premature mixing of the components. Each different component may be provided separately, or some of the different components may be provided together (i.e., in the same container).

[0197] A container can also be a vial, tube, jar, or envelope, or sleeve, or blister package, or compartment or chamber within a bottle, so long as the contents of one compartment cannot be physically associated with the contents of another compartment prior to intentional mixing by a pharmacist or physician.

[0198] The kit or kit-of-parts may further comprise technical instructions containing information regarding the administration and / or dosage of any of its components.

[0199] Therapeutic and diagnostic methods and uses According to a further aspect, the present invention also provides a conjugate (compound) (including pharmaceutically acceptable salts, esters, solvates, and radiolabeled complexes), pharmaceutical composition, or kit according to the present invention for use in medicine. Furthermore, the present invention also provides a conjugate or compound (including pharmaceutically acceptable salts, esters, solvates, and radiolabeled complexes), pharmaceutical composition, or kit according to the present invention for use in diagnostic agents. Preferably, the conjugate (compound), pharmaceutical composition, or kit of the present invention is used for human medical purposes. Thus, the present invention further encompasses a conjugate (compound), pharmaceutical composition, or kit of the present invention for use as a medicine.

[0200] The conjugate (compound) of the present invention is preferably capable of selectively targeting prostate-specific membrane antigen (PSMA). Thus, according to a particular aspect, the present invention provides the conjugate (compound), pharmaceutical composition, or kit of the present invention for use in a method for detecting the presence of cells and / or tissues expressing prostate-specific membrane antigen (PSMA).

[0201] PSMA is particularly expressed in malignant cancer cells. As used herein, the term "cancer" refers to neoplasms, particularly malignant neoplasms. Neoplasms are usually characterized by uncontrolled, usually rapid, proliferation of cells that tend to invade surrounding tissues and metastasize to distant body sites. The term "neoplasm" encompasses benign and malignant neoplasms. Malignant neoplasms (cancers) are usually characterized by anaplasia, invasiveness, and / or metastasis, while benign tumors usually do not possess these properties. The term "cancer" includes neoplasms characterized by tumor growth (e.g., solid tumors) as well as other cancers, such as cancers of the blood and lymphatic system.

[0202] Specifically, PSMA can be expressed in optionally high amounts in prostate, pancreatic, renal, or bladder cancer cells.

[0203] According to further particular aspects, the present invention provides a conjugate (compound) of the invention (including pharmaceutically acceptable salts, esters, solvates, and radiolabeled complexes thereof), pharmaceutical composition, or kit for use in a method for diagnosing, treating, and / or preventing cancer, in particular prostate cancer, pancreatic cancer, renal cancer, or bladder cancer.

[0204] The terms "diagnosis" or "diagnosing" refer to the act of identifying a disease from its signs and symptoms and / or, in this case, the analysis of biological markers (e.g., genes or proteins) that are indicative of the disease.

[0205] The term "treatment" or "treating" a disease includes preventing or protecting against the disease (i.e., preventing clinical symptoms from developing); inhibiting the disease (i.e., arresting or suppressing the development of clinical symptoms) and / or alleviating the disease (i.e., causing regression of clinical symptoms). As will be appreciated, it is not always possible to distinguish between "preventing" and "suppressing" a disease or disorder, as the ultimate precipitating event or events may be unknown or latent. Thus, the term "prevention" is understood to constitute a type of "treatment" that encompasses both "preventing" and "suppressing." Thus, the term "treatment" includes "prevention."

[0206] As used herein, the terms "subject," "patient," or "individual" generally include humans and non-human animals, preferably mammals (e.g., non-human primates such as marmosets, tamarins, spider monkeys, owl monkeys, vervet monkeys, squirrel monkeys, baboons, macaques, chimpanzees, orangutans, gorillas; cows; horses; sheep; pigs; birds; cats; dogs; mice; rats; rabbits; guinea pigs), including chimeric and transgenic animals and disease models. In the context of the present invention, the term "subject" preferably refers to a non-human primate or a human, most preferably a human.

[0207] The uses and methods described herein for the diagnosis, treatment, or prevention of cancer, particularly prostate, pancreatic, renal, or bladder cancer, may preferably comprise the steps of: (a) administering to a patient a conjugate (including pharmaceutically acceptable salts, esters, solvates, and radiolabeled complexes thereof), pharmaceutical composition, or kit of the present invention; and (b) obtaining a radiological image from said patient.

[0208] The conjugate (compound), pharmaceutical composition, or kit of the present invention is typically administered parenterally. Administration is preferably systemic, for example, by intravenous (iv), subcutaneous, intramuscular, or intradermal injection. Alternatively, administration can be locally, for example, by intratumoral injection.

[0209] The conjugate (compound), pharmaceutical composition, or kit of the present invention can be administered to a subject in need thereof several times a day, once a day, once every other day, once a week, or once a month. Preferably, treatment, diagnosis, or prevention is carried out with an effective dose of the conjugate, pharmaceutical composition, or kit of the present invention.

[0210] Effective doses of the conjugates of the invention can be determined by routine experiments, for example, using animal models. Such models include, but are not limited to, rabbit, sheep, mouse, rat, dog, and non-human primate models. The therapeutic efficacy and toxicity of the conjugates or radiolabeled complexes of the invention can be determined by standard pharmaceutical procedures in cell cultures or experimental animals, for example, to determine the LD50 (lethal dose for 50% of a population) and ED50 (the dose therapeutically effective in 50% of a population). The dose ratio between toxic and therapeutic effects is the therapeutic index, which can be expressed as the ratio LD50 / ED50. Data obtained from cell culture assays and animal studies can be used to determine a dosage range for use in humans. The dose of the conjugate preferably lies within a range of circulating concentrations that include the ED50 with little or no toxicity.

[0211] For example, a therapeutically or diagnostically effective dose of a conjugate of the present invention is about 0.001 mg to 10 mg per dosage unit, preferably about 0.01 mg to 5 mg, more preferably about 0.1 mg to 2 mg, or about 0.01 nmol to 1 mmol per dosage unit, particularly 1 nmol to 1 mmol per dosage unit, preferably 1 μmol to 1 mmol per dosage unit. It is also contemplated that a therapeutically or diagnostically effective dose of a conjugate (compound) of the present invention may range from about 0.01 mg / kg to 10 g / kg (per kg body weight), preferably about 0.05 mg / kg to 5 g / kg, more preferably about 0.1 mg / kg to 2.5 g / kg. Advantageously, due to their favorable pharmacokinetic properties, the conjugates of the present invention can preferably be administered at lower doses than other PSMA ligands.

[0212] As established above, the conjugates of the present invention are particularly useful for therapeutic diagnostic applications, including targeting PSMA-expressing cells. As used herein, the term "therapeutic diagnostic agent" includes "therapeutic only," "diagnostic only," and "therapeutic and diagnostic" applications. In a further aspect, the present invention relates to an in vitro method for detecting the presence of cells and / or tissues expressing prostate-specific membrane antigen (PSMA), comprising: (a) contacting said PSMA-expressing cells and / or tissues with a conjugate of the present invention (including pharmaceutically acceptable salts, esters, solvates, and radiolabeled complexes thereof), pharmaceutical composition, or kit; and (b) applying a detection means, optionally radioimaging, to detect said cells and / or tissues.

[0213] In the in vivo and in vitro uses and methods of the present invention, radioimaging can be achieved using any means and methods known in the art.Preferably, radioimaging can include positron emission tomography (PET) or single photon emission computed tomography (SPECT).The target cells or tissues detected by radioimaging of the conjugates of the present invention can preferably include (optionally cancerous) prostate cells or tissues, (optionally cancerous) spleen cells or tissues, or (optionally cancerous) kidney cells or tissues.

[0214] In the in vivo and in vitro uses and methods of the present invention, the presence of PSMA-expressing cells or tissues can be indicative of prostate tumors (cells), metastatic prostate tumors (cells), kidney tumors (cells), pancreatic tumors (cells), bladder tumors (cells), and combinations thereof. Thus, the conjugates (including pharmaceutically acceptable salts, esters, solvates, and radiolabeled complexes thereof), pharmaceutical compositions, and kits of the present invention can be particularly used for the diagnosis (and optionally treatment) of prostate cancer, kidney cancer, pancreatic cancer, or bladder cancer.

[0215] A brief description of the accompanying drawings will now be given, which are intended to explain the invention in more detail, but which are not intended to limit the subject matter of the invention in any way. [Brief explanation of the drawings]

[0216] [Figure 1] FIG. 1 shows, in Scheme 1, the synthesis of the glutamic acid-urea-lysine binding motif of Ibu-DAB-PSMA. [Figure 2] FIG. 2 shows the synthesis of the linker region, which is the precursor of Ibu-Dab-PSMA, in Scheme 2. [Figure 3] FIG. 3 shows, in Scheme 3, the synthesis of a DOTA conjugate precursor for Ibu-Dab-PSMA. [Figure 4] FIG. 4 shows the coupling of an additional linker moiety of Ibu-DAB-PSMA to an albumin conjugate in Scheme 4. [Figure 5]Figure 5 shows representative HPLC chromatograms of ibuprofen-derivatized 177Lu-PSMA ligands, as described in Example 4. (A) Chromatogram of 177Lu-Ibu-PSMA, (B) chromatogram of 177Lu-Ibu-Dβ-PSMA, (C) chromatogram of 177Lu-Ibu-Dα-PSMA, (D) chromatogram of 177Lu-Ibu-N-PSMA, and (E) chromatogram of 177Lu-Ibu-DAB-PSMA. Retention times (tR) are indicated in each figure. [Figure 6] Figure 6 shows the n-octanol / PBS partition coefficients of 177Lu-Ibu-PSMA, 177Lu-Ibu-Dβ-PSMA, 177Lu-Ibu-Dα-PSMA, 177Lu-Ibu-N-PSMA, and 177Lu-Ibu-DABP-PSMA compared to the reference compound 177Lu-PSMA-617, for Example 5. Experiments were performed three times in quintuplicate (n=3). [Figure 7] Figure 7, referring to Example 6, shows ultrafiltration assay data for 177Lu-Ibu-PSMA, 177Lu-Ibu-Dβ-PSMA, 177Lu-Ibu-Dα-PSMA, 177Lu-Ibu-N-PSMA, and 177Lu-Ibu-DAB-PSMA compared to 177Lu-PSMA-617 (n=3). [Figure 8] Figure 8, relating to Example 7, shows the uptake and internalization of 177Lu-Ibu-PSMA, 177Lu-Ibu-Dβ-PSMA, 177Lu-Ibu-Dα-PSMA, 177Lu-Ibu-N-PSMA, and 177Lu-Ibu-DAB-PSMA compared to 177Lu-PSMA-617. (A) Data obtained with PSMA-positive PC-3PIP cells (n=3). (B) Data obtained with PSMA-positive PC-3flu cells (n=1). [Figure 9] Figure 9, relating to Example 8, shows biodistribution data for five ibuprofen-derivatized radioligands and 177Lu-PSMA-617 obtained in PC-3PIP / flu tumor-bearing mice. (A) Biodistribution data obtained 4 hours after injection of the radioligand. (B) Biodistribution data obtained 24 hours after injection of the radioligand. [Figure 10]Figure 10 shows tumor-to-background ratios at 4 and 24 hours after injection of 177Lu-PSMA ligands for Example 8. (A) Tumor-to-blood ratio, (B) tumor-to-liver ratio, and (C) tumor-to-kidney ratio for all 177Lu-Ibu-PSMA ligands at 4 h and 24 hp.i. [Figure 11] Figure 11 shows the total body radioactivity measured with dose calibrators at 0, 4, 24, 48, and 72 hours after injection of each radioligand, as described in Example 9. Radioactivity measured immediately after injection was set at 100%. Data for the comparison radioligands 177Lu-PSMA-ALB-53 / 56 and 177LuPSMA617 are included in this graph for comparison. Data points represent the average of two mice injected with the same radioligand (n=2). [Figure 12] 12 shows SPECT / CT images obtained 4 hours after injection of 177Lu-PSMA ligand, shown as maximum intensity projections (MIPs), for Example 10. (A) 177Lu-Ibu-PSMA, (B) 177Lu-Ibu-Dβ-PSMA, (C) 177Lu-Ibu-Dβ-PSMA, (D) 177Lu-Ibu-N-PSMA, (E) 177Lu-Ibu-DAB-PSMA. PSMA+ = PSMA-positive PC-3PIP tumor xenograft, PSMA- = PSMA-negative PC-3flu tumor xenograft, Ki = kidney, Bl = bladder. [Figure 13] FIG. 13 shows a scheme illustrating the coupling of an ibuprofen moiety to Precursor 1 (containing a PSMA conjugate and a DOTA chelator) to synthesize Ibu-sPSMA. [Figure 14] Figure 14 shows a representative HPLC chromatogram of 177Lu-Ibu-sPSMA. The retention time tr is indicated in the figure. [Figure 15]Figure 15 shows radiolytic stability expressed as the percentage of intact 177Lu-Ibu-sPSMA for up to 24 hours. (A) 177Lu-Ibu-sPSMA incubated without L-ascorbic acid, (B) 177Lu-Ibu-sPSMA incubated with L-ascorbic acid (mean ± SD, n = 3). 177Lu-Ibu-sPSMA was significantly more stable than 177Lu-PSMA-617 and all other ibuprofen-derivatized PSMA radioligands. The stability of 177Lu-Ibu-sPSMA was comparable to that of 177Lu-PSMA-ALB-56. [Figure 16] FIG. 16 shows data from an ultrafiltration assay comparing 177Lu-Ibu-sPSMA with 177Lu-PSMA-617 (n=3). [Figure 17] Figure 17 shows the uptake and internalization of 177Lu-Ibu-sPSMA compared to 177Lu-PSMA-617. (A) Data obtained in PSMA-positive PC-3PIP cells (n=3). (B) Data obtained in PSMA-negative PC-3flu cells (n=3). [Figure 18] Figure 18 shows graphs depicting biodistribution data for 177Lu-Ibu-PSMA, 177Lu-Ibu-DAB-PSMA, 177Lu-Ibu-sPSMA, and 177Lu-Ibu-PSMA-617 obtained in PC-3PIP / flu tumor-bearing mice. (A) Biodistribution data obtained 1 hour after injection of the radioligand. (B) Biodistribution data obtained 4 hours after injection of the radioligand. (C) Biodistribution data obtained 24 hours after injection of the radioligand. (D) Biodistribution data obtained 96 hours after injection of the radioligand. [Figure 19] Figure 19 is a graph showing the tumor-to-background ratios at 1, 4, 24, and 96 hours after injection of 177Lu-Ibu-sPSMA compared to 177Lu-Ibu-PSMA and 177Lu-Ibu-DAB-PSMA: (A) tumor-to-blood ratio, (B) tumor-to-kidney ratio, and (C) tumor-to-liver ratio. [Figure 20]Figure 20 shows total body radioactivity measured with dose calibrators at various time points after injection. Radioactivity measured immediately after injection was set to 100%. Published data for 177Lu-PSMA-617 are included in the graph for comparison. Data points represent the average of two mice injected with the same radioligand (n = 2-3). (A) Graph shows data for all radioligands. (B) Graph shows data for 177Lu-Ibu-PSMA, 177Lu-Ibu-DAB-PSMA, 177Lu-PSMA-617, and 177Lu-PSMA-ALB-56 to more clearly visualize the single elimination curves. [Figure 21] Figure 21 shows SPECT / CT images obtained after injection of 177Lu-Ibu-sPSMA, shown as maximum intensity projections (MIPs). (A) SPECT / CT image acquired at 4 hp.i. (B) SPECT / CT image acquired at 24 hp.i. PSMA+ = PSMA-positive PC-3PIP tumor xenograft, PSMA- = PSMA-negative PC-3flu tumor xenograft, Ki = kidney, Bl = bladder. [Figure 22] Figure 22 shows the relative tumor growth in control mice and mice treated with (a) lower radioactivity (2 MBq, 1 nmol per mouse) or (b) higher radioactivity (5 MBq, 1 nmol per mouse). Groups of mice were injected with vehicle (saline) only (●), 177Lu-Ibu-DAB-PSMA (■), 177Lu-PSMA-617 (▲), or 177Lu-PSMA-ALB-56 (▼) on day 6 after tumor cell inoculation (mean ± SD, n = 6–12). The mean relative tumor volume for each group is shown until the first mouse reached endpoint. [Figure 23] Figure 23 shows Kaplan-Meier plots (n = 6–12) showing survival curves for mice in each group: control mice and mice treated with (a) lower injected radioactivity (2 MBq, 1 nmol per mouse) or (b) higher injected radioactivity (5 MBq, 1 nmol per mouse). Untreated control mice (-), 177Lu-Ibu-DAB-PSMA (- - -), 177Lu-PSMA-617 (-··-··), and 177Lu-PSMA-ALB-56 (···). [Figure 24] Figure 24 shows the relative body mass (RBM) of control mice and mice treated with (a) lower injected radioactivity (2 MBq, 1 nmol per mouse) or (b) higher injected radioactivity (5 MBq, 1 nmol per mouse). The mean RBM of mice injected with vehicle (saline) only (●), 177Lu-Ibu-DAB-PSMA (■), 177Lu-PSMA-617 (▲), and 177Lu-PSMA-ALB-56 (▼). The mean RBM of each group is shown until the first mouse reaches the endpoint. [Example]

[0217] Below, specific examples illustrating various embodiments and aspects of the present invention are presented. However, the present invention is not limited in scope by the specific embodiments described herein. The following preparations and examples are provided to enable those skilled in the art to more clearly understand and practice the present invention. However, the present invention is not limited in scope by the exemplified embodiments, which are intended as merely examples of individual aspects of the invention, and functionally equivalent methods are within the scope of the invention. Indeed, various modifications of the present invention in addition to those described herein will be readily apparent to those skilled in the art from the foregoing description, the accompanying drawings, and the following examples. All such modifications are intended to be encompassed within the scope of the appended claims.

[0218] Example 1: Structural design of exemplary PSMA ligands To identify PSMA ligands that provide a balance between (i) binding of the radioligand to albumin to achieve an optimal tissue distribution profile with high tumor uptake and (ii) blood radioactivity levels that are not so excessively high as to pose a risk of unwanted side effects on healthy tissue, five ibuprofen-derivatized PSMA ligands were designed (Ibu-PSMA, Ibu-Dα-PSMA, Ibu-Dβ-PSMA, Ibu-N-PSMA, and Ibu-DAB-PSMA). Ibu-PSMA: [ka] Ibu-Dα-PSMA: [ka] Ibu-Dβ-PSMA: [ka] Ibu-N-PSMA: [ka] 1.5.Ibu-DAB-PSMA: [ka]

[0219] The simplest design of ibuprofen-derivatized PSMA ligands is Ibu-PSMA. It was designed by directly conjugating ibuprofen to a lysine residue, introducing albumin-binding ibuprofen without an additional spacer entity. In Ibu-Dα-PSMA and Ibu-Dβ-PSMA, an additional spacer based on D-aspartic acid (D-Asp, D) was used (in addition to the L-Lys residue) to introduce an additional negative charge into the construct. D-Asp was conjugated via the α-carboxyl group to yield Ibu-Dα-PSMA or via the β-carboxyl group to yield Ibu-Dβ-PSMA. In Ibu-N-PSMA, a different additional spacer entity based on D-asparagine (D-Asn, N) was used (in addition to the L-Lys residue) to function as a neutral entity. Finally, the design of Ibu-DAB-PSMA was based on the use of D-diaminobutyric acid (DAB) as an additional spacer entity (in addition to the L-Lys residue) to introduce an additional positive charge into the construct.

[0220] 1.6.Ibu-sPSMA: Ibu-sPSMA was designed similarly to Ibu-PSMA, but unlike Ibu-PSMA, in which the ibuprofen moiety is connected via a lysine side chain, the shorter L-2,4-diaminobutyric acid (L-DAB) was used as the connecting unit. [ka]

[0221] Example 2: Chemical synthesis of exemplary PSMA ligands 2.1. Synthetic Strategy and Analysis of PSMA Ligands All five proposed PSMA ligands bearing albumin-binding moieties were synthesized using a solid-phase platform, following previous reports on the synthesis of other PSMA ligands (Umbricht, CA; Benesova, M.; Schibli, R.; Muller, C. Preclinical development of novel PSMA-targeting radioligands: modulation of albumin-binding properties to improve prostate cancer therapy. Mol Pharm 2018, Mol Pharm 2018, 15, (6), 2297-2306). This technology was shown to be useful for the development of the described ibuprofen-derivatized PSMA ligands. Multistep synthesis (17 steps for Ibu-PSMA and 19 steps for Ibu-Dα-PSMA, Ibu-Dβ-PSMA, Ibu-N-PSMA, and Ibu-DAB-PSMA) afforded these ligands in overall isolated yields of ≥2.8% after HPLC purification. The ligands were characterized by analytical RP-HPLC and MALDI-MS, respectively. The chemical purity of each compound was ≥99.2%. Analytical data are shown in Table 1. Table 1. Analytical data for PSMA ligands: Ibu-PSMA, Ibu-Dα-PSMA, Ibu-Dβ-PSMA, Ibu-N-PSMA, and Ibu-DAB-PSMA [Table 1] a m / z peaks of unlabeled ligands obtained by mass spectrometry. b Measured by analytical HPLC, λ=254nm.

[0222] 2.2. Synthesis of Precursor 1 The PSMA-targeting urea-based PSMA conjugate, L-Glu-NH-CO-NH-L-Lys, was prepared on 2-chlorotrityl chloride (2-CT) resin similarly to the method described by Eder et al. (Eder, M.; Schafer, M.; Bauder-Wust, U.; Hull, W.E.; Wangler, C.; Mier, W.; Haberkorn, U.; Eisenhut, M.). 68Ga-complex lipophilicity and the targeting property of a urea-based PSMA inhibitor for PET imaging. Bioconjug Chem 2012, 23, (4), 688-97). The linker region consisting of 2-naphthyl-L-Ala and trans-cyclohexyl moieties was synthesized according to a previous report by Benesova et al. (Benesova, M.; Schafer, M.; Bauder-Wust, U.; Afshar-Oromieh, A.; Kratochwil, C.; Mier, W.; Haberkorn, U.; Kopka, K.; Eder, M. Preclinical evaluation of a tailor-made DOTA-conjugated PSMA inhibitor with optimized linker moiety for imaging and endoradiotherapy of prostate cancer. J Nucl Med 2015, 56, (6), 914-20). The conjugation of a DOTA chelator conjugated to the construct via Nα-amino-L-Lys has previously been reported by Umbricht et al. (Umbricht, CA; Benesova, M.; Schibli, R.; Muller, C. Preclinical development of novel PSMA-targeting radioligands: modulation of albumin-binding properties to improve prostate cancer therapy. Mol Pharm 2018, Mol Pharm 2018, 15, (6), 2297-2306).

[0223] The following resin-immobilized precursor was used as the basis for the synthesis of a PSMA ligand ("Precursor 1"). [ka] Precursor 1 is based on a PSMA conjugate and a DOTA chelator. This precursor was used for the synthesis of five exemplary ligands: Ibu-PSMA, Ibu-Dα-PSMA, Ibu-Dβ-PSMA, Ibu-N-PSMA, and Ibu-DAB-PSMA. The free amino group of the lysine side chain was used for the conjugation of ibuprofen, either directly or via an amino acid entity.

[0224] Synthesis of Ibu-PSMA Ibu-PSMA was synthesized by coupling albumin-conjugated ibuprofen to the resin-immobilized precursor 1. The resin was swollen in anhydrous dichloromethane (DCM, Acros Organics) for 45 min and then conditioned in N,N-dimethylformamide (DMF, Acros Organics). Resin-immobilized precursor 1 (0.10 mmol) was activated with 4.0–6.0 equivalents of 2-(4-(2-methylpropyl)phenyl)propanoic acid (ibuprofen; Sigma Aldrich; 0.400–0.600 mmol) and 3.96 equivalents of N,N,N',N'-tetramethyl-O-(1H-benzotriazol-1-yl)-uronium hexafluorophosphate (HBTU; Sigma Aldrich; 0.396–0.594 mmol) in the presence of 4.0–6.0 equivalents of DIPEA (N,N-diisopropylethylamine; Sigma Aldrich; 0.400–0.600 mmol) in anhydrous DMF. Two minutes after the addition of DIPEA, the activated solution was added to precursor 1 and stirred for up to 2 hours. The resin was washed with DMF, DCM, and diethyl ether, respectively, and dried under reduced pressure. After cleavage from the resin, the product was deprotected within 3–6 h using a mixture of trifluoroacetic acid (TFA, Sigma-Aldrich), triisopropylsilane (TIPS, Sigma-Aldrich), and Milli-Q water in a 95:2.5:2.5 (v / v) ratio. TFA was evaporated, and the crude compound was dissolved in acetonitrile (ACN, VWR Chemicals) and Milli-Q water in a 1:2 (v / v) ratio and purified by RP-HPLC to obtain Ibu-PSMA.

[0225] 2.4. Synthesis of Ibu-Dα-PSMA An additional spacer entity consisting of D-aspartic acid (D-Asp) was conjugated to the Nε-L-lysine of precursor 1, followed by coupling with ibuprofen. Resin-immobilized precursor 1 was pre-swollen in DCM and conditioned with DMF as described above. To precursor 1 (0.100 mmol), 4.0 equivalents of Fmoc- and t-Bu-protected D-Asp (Fmoc-D-Asp(Ot-Bu)-OH, Sigma-Aldrich, 0.400 mmol) were activated with 3.96 equivalents of HBTU (0.396 mmol) in the presence of a solution of 4.0 equivalents of DIPEA (0.400 mmol) in anhydrous DMF. Two minutes after the addition of DIPEA, the activation solution was added to precursor 1 and stirred for up to 2 hours. The resin was washed with DMF. The Nα-Fmoc protecting group was cleaved twice with a 1:1 (v / v) mixture of DMF and piperidine (Fluka) by stirring for 5 min. The resin was washed again with DMF. Ibuprofen (4.0–6.0 equiv; 0.400–0.600 mmol) was activated with 3.96 equiv of HBTU (0.396–0.594 mmol) in the presence of 4.0–6.0 equiv of DIPEA (0.400–0.600 mmol) in anhydrous DMF. Two minutes after the addition of DIPEA, the activation solution was added to the resin and stirred for up to 2 h. The resin was then washed with DMF, DCM, and diethyl ether, respectively, and dried under reduced pressure. The product was cleaved from the resin and simultaneously deprotected within 3–6 h with a mixture of TFA, TIPS, and water in a 95:2.5:2.5 (v / v) ratio. TFA was evaporated and the crude compound was dissolved in acetonitrile (ACN, VWR Chemicals) and Milli-Q water in a 1:2 (v / v) ratio and purified by RP-HPLC to give Ibu-Dα-PSMA.

[0226] 2.5. Synthesis of Ibu-Dβ-PSMA An additional spacer entity consisting of D-aspartic acid (D-Asp) was conjugated to the Nε-L-lysine of precursor 1, followed by coupling with ibuprofen. Resin-bound precursor 1 was pre-swollen in DCM and conditioned in DMF as described above. To precursor 1 (0.100 mmol), 4.0 equivalents of Fmoc- and t-Bu-protected D-Asp (Fmoc-D-Asp-Ot-Bu, Merck Group, 0.400 mmol) were activated with 3.96 equivalents of HBTU (0.396 mmol) in the presence of 4.0 equivalents of DIPEA (0.400 mmol) in anhydrous DMF. Two minutes after the addition of DIPEA, the activated solution was added to precursor 1 and stirred for up to 2 hours. The resin was washed with DMF, and the Nα-Fmoc protecting group was cleaved by stirring twice for 5 min with a 1:1 (v / v) mixture of DMF and piperidine (Fluka). The resin was washed again with DMF. Ibuprofen (4.0–6.0 equiv; 0.400–0.600 mmol) was activated with 3.96 equiv of HBTU (0.396–0.594 mmol) in the presence of 4.0–6.0 equiv of DIPEA (0.400–0.600 mmol) in anhydrous DMF. Two minutes after the addition of DIPEA, the activation solution was added to the resin and stirred for up to 2 h. The resin was then washed with DMF, DCM, and diethyl ether, respectively, and dried under reduced pressure. The product was cleaved from the resin and simultaneously deprotected within 3–6 h with a mixture of TFA, TIPS, and water in a 95:2.5:2.5 (v / v) ratio. TFA was evaporated, and the crude compound was dissolved in acetonitrile (ACN, VWR Chemicals) and Milli-Q water in a 1:2 (v / v) ratio and purified by RP-HPLC to give Ibu-Dβ-PSMA.

[0227] 2.6. Synthesis of Ibu-N-PSMA An additional spacer entity consisting of D-asparagine (D-Asn) was conjugated to the Nε-L-lysine of precursor 1, followed by coupling with ibuprofen. Resin-immobilized precursor 1 was pre-swollen in DCM and conditioned in DMF as described above. To precursor 1 (0.100 mmol), 4.0 equivalents of Fmoc- and trityl-protected D-asparagine (Fmoc-D-Asn(Trt)-OH, Sigma-Aldrich, 0.400 mmol) were activated with 3.96 equivalents of HBTU (0.396 mmol) in the presence of 4.0 equivalents of DIPEA (0.400 mmol) in anhydrous DMF. Two minutes after the addition of DIPEA, the activated solution was added to precursor 1 and stirred for up to 3 hours. The resin was washed with DMF, and the Nα-Fmoc protecting group was cleaved by stirring twice for 5 minutes with a 1:1 (v / v) mixture of DMF and piperidine (Fluka). The resin was washed again with DMF. Ibuprofen (4.0–6.0 equiv; 0.400–0.600 mmol) was activated with 3.96 equiv of HBTU (0.396–0.594 mmol) in the presence of 4.0–6.0 equiv of DIPEA (0.400–0.600 mmol) in anhydrous DMF. Two minutes after the addition of DIPEA, the activation solution was added to the resin and stirred for up to 2 hours. The resin was then washed with DMF, DCM, and diethyl ether, respectively, and dried under reduced pressure. The product was cleaved from the resin within 3–6 hours with a mixture of TFA, TIPS, and water in a 95:2.5:2.5 (v / v) ratio. The t-Bu protecting group and the additional Trt protecting group were simultaneously cleaved. TFA was evaporated, and the crude compound was dissolved in acetonitrile (ACN, VWR Chemicals) and Milli-Q water in a 1:2 (v / v) ratio and purified by RP-HPLC to give Ibu-N-PSMA.

[0228] Synthesis of Ibu-DAB-PSMA An additional spacer entity consisting of D-diaminobutyric acid was conjugated to the Nε-L-lysine of precursor 1, followed by coupling with ibuprofen. Resin-immobilized precursor 1 was pre-swollen in DCM and conditioned in DMF as described above. To precursor 1 (0.100 mmol), 4.0 equivalents of Fmoc- and Boc-protected D-diaminobutyric acid (DAB; Fmoc-D-Dab(Boc)-OH, Iris Biotech, 0.400 mmol) were activated with 3.96 equivalents of HBTU (0.396 mmol) in the presence of 4.0 equivalents of DIPEA (0.400 mmol) in anhydrous DMF. Two minutes after the addition of DIPEA, the activated solution was added to precursor 1 and stirred for up to 3.5 hours. The resin was washed with DMF, and the Nα-Fmoc protecting group was cleaved by stirring twice for 5 min with a 1:1 (v / v) mixture of DMF and piperidine (Fluka). The resin was washed again with DMF. Ibuprofen (4.0–6.0 equiv; 0.400–0.600 mmol) was activated with 3.96 equiv of HBTU (0.396–0.594 mmol) in the presence of 4.0–6.0 equiv of DIPEA (0.400–0.600 mmol) in anhydrous DMF. Two minutes after the addition of DIPEA, the activation solution was added to the resin and stirred for up to 2 h. The resin was then washed with DMF, DCM, and diethyl ether, respectively, and dried under reduced pressure. The product was cleaved from the resin within 3–6 h with a mixture of TFA, TIPS, and water in a 95:2.5:2.5 (v / v) ratio. The t-Bu and additional Boc protecting groups were cleaved simultaneously. TFA was evaporated, and the crude compound was dissolved in acetonitrile (ACN, VWR Chemicals) and Milli-Q water in a 1:2 (v / v) ratio and purified by RP-HPLC to give Ibu-DAB-PSMA.

[0229] 2.8. Synthesis of Ibu-sPSMA Similar to other ibuprofen-containing PSMA ligands, Ibu-sPSMA was synthesized by a solid-phase platform (Umbricht, CA; Mol Pharm 2018, 15,(6):2297-2306) according to previous reports on the synthesis of other PSMA ligands (see also Section 2 above). A multistep synthesis (17 steps) afforded this ligand in an overall isolated yield of ≥14% after HPLC purification.

[0230] 2.8.1. Synthesis of Precursor 1 The PSMA-targeting urea-based PSMA conjugate, L-Glu-NH-CO-NH-L-Lys, was prepared on 2-chlorotrityl chloride (2-CT) resin using a method similar to that described by Eder et al. (Bioconjug Chem 2012, 23, (4), 688-97) (see also Section 2 above). The linker region, consisting of 2-naphthyl-L-Ala and trans-cyclohexyl moieties, was synthesized according to a previous report by Benesova et al. (J Nucl Med 2015, 56, (6), 914-20). However, in this case, a different precursor was used than for other Ibu-PSMA ligands. The linker entity, L-diaminobutyric acid, was two carbon atoms shorter than the L-lysine used as the linker for Ibu-PSMA synthesis. Conjugation of a DOTA chelator to the construct was previously reported by Umbricht et al. (Mol Pharm 2018, 15,(6):2297-2306).

[0231] The following resin-immobilized precursor (Precursor 1) was used as the basis for the synthesis of Ibu-sPSMA. Precursor 1 is based on a PSMA conjugate and a DOTA chelator. This precursor contains a shorter connecting entity than those used in other Ibu-PSMA ligands (e.g., Ibu-PSMA). [ka]

[0232] 2.8.2. Synthesis of Ibu-sPSMA Ibu-sPSMA was synthesized by coupling albumin-bound ibuprofen to resin-immobilized precursor 1 (Figure 13). The free γ-amino group of the diaminobutyric acid side chain was used for the conjugation of ibuprofen. The resin was swollen in anhydrous dichloromethane (DCM, Acros Organics) for 45 min and then conditioned in N,N-dimethylformamide (DMF, Acros Organics). For resin-immobilized precursor 1 (0.10 mmol), 6.0 equivalents of 2-(4-(2-methylpropyl)phenyl)propanoic acid (ibuprofen; Sigma Aldrich; 0.60 mmol) were activated with 5.94 equivalents of N,N,N',N'-tetramethyl-O-(1H-benzotriazol-1-yl)-uronium hexafluorophosphate (HBTU; Sigma Aldrich; 0.59 mmol) in the presence of 8.0 equivalents of DIPEA (N,N-diisopropylethylamine; Sigma Aldrich; 0.80 mmol) in anhydrous DMF. Two minutes after the addition of DIPEA, the activated solution was added to precursor 1 and stirred for up to 2 hours to produce resin-immobilized compound 2 (Figure 13). The resin was washed with DMF, DCM, and diethyl ether, respectively, and dried under reduced pressure. The product was cleaved from the resin and subsequently deprotected within 2 h using a mixture of trifluoroacetic acid (TFA, Sigma Aldrich), triisopropylsilane (TIPS, Sigma Aldrich), and Milli-Q water in a 95:2.5:2.5 (v / v) ratio to give the crude product (Figure 13). The TFA was evaporated, and the crude compound was dissolved in acetonitrile (ACN, VWR Chemicals) and Milli-Q water in a 1:2 (v / v) ratio and purified by HPLC to give pure Ibu-PSMA. The ligand was characterized by analytical HPLC and MALDI-MS. The chemical purity of the compound was ≥99%. The analytical data are shown in Table 2. Table 2. Analysis data of Ibu-sPSMA [Table 2] am / z peaks of unlabeled ligands obtained by mass spectrometry. b Measured by analytical HPLC, λ=254nm

[0233] 2.9. Synthesis of the Example Compound Ibu-DAB-PSMA Synthesis Schemes 1 to 4, shown in Figures 1 to 4, respectively, show the details of the synthesis of the example compound Ibu-DAB-PSMA. The synthesis of the other example compounds was carried out in a similar manner.

[0234] Example 4: Radiolabeling and Stability Stock solutions of the prior art PSMA-ligand PSMA-617 (ABX GmbH, Radeberg, Germany) were prepared by diluting the ligand in Milli-Q water to a final concentration of 1 mM. Ibu-PSMA, Ibu-Dα-PSMA, Ibu-Dβ-PSMA, Ibu-N-PSMA, and Ibu-DAB-PSMA were diluted with Milli-Q water / sodium acetate (0.5 M, pH 8) to a final concentration of 1 mM. All PSMA ligands were prepared in a 1:5 (v / v) mixture of sodium acetate (0.5 M, pH 8) and HCl (0.05 M, pH 1). 177 Lu (no-carrier added in 0.05M HCl) 177 The PSMA ligand was labeled with 100 u (Isotope Technologies Garching ITG GmbH, Germany) at pH 4.5 with specific activities ranging from 5 to 50 MBq / nmol, depending on the experiment being performed. 177 The reaction mixture was incubated at 95°C for 10 minutes and then loaded onto a C-18 reversed-phase column (Xterra TM Quality control was performed using RP-HPLC equipped with a MS, C18, 5 μm, 150 × 4.6 mm (Waters). The mobile phase consisted of Milli-Q water containing 0.1% trifluoroacetic acid (A) and acetonitrile (B), with a gradient of 95% A and 5% B to 20% A and 80% B over 15 min at a flow rate of 1.0 mL / min. The radioligand was diluted with Milli-Q water containing Na-DTPA (50 μM) before injection into the HPLC. Figure 5 shows a representative HPLC chromatogram.

[0235] Example 5: n-Octanol / PBS partition coefficient Five exemplary PSMA binders 177 Lu-Ibu-PSMA, 177 Lu-Ibu-Dα-PSMA, 177 Lu-Ibu-Dβ-PSMA, 177 Lu-Ibu-N-PSMA, and 177 The n-octanol / PBS partition coefficient of Lu-Ibu- in the n-octanol / PBS system was measured as previously reported (Benesova, M.; Umbricht, CA; Schibli, R.; Muller, C. Albumin-binding PSMA ligands: optimization of the tissue distribution profile. Mol Pharm 2018, 15, (3), 934-946).

[0236] The results are shown in Figure 6. All radioligands exhibited hydrophilicity with log D values ​​of <2.2. 177 Lu-Ibu-PSMA, 177 Lu-Ibu-N-PSMA, and 177 Lu-Ibu-DAB-PSMA showed similar values, 177 Lu-Ibu-Dβ-PSMA and 177 The coefficient for Lu-Ibu-Dα-PSMA is slightly lower, indicating it is more hydrophilic. Modification of the PSMA ligand with ibuprofen is comparable to that of the prior art PSMA ligands that do not contain albumin conjugates. 177 The effect was due to the more hydrophobic nature of the radioligand compared to Lu-PSMA-617.

[0237] Example 6: Albumin binding properties in vitro Five exemplary PSMA binders 177 Lu-Ibu-PSMA, 177 Lu-Ibu-Dα-PSMA, 177 Lu-Ibu-Dβ-PSMA, 177 Lu-Ibu-N-PSMA, and 177Plasma Protein Binding Properties of Lu-Ibu-DAB-PSMA and Prior Art PSMA Binders 177 Lu-PSMA-617 (free of albumin conjugates) was determined using an ultrafiltration assay as previously reported (Benesova, M.; Umbricht, CA; Schibli, R.; Muller, C. Albumin-binding PSMA ligands: optimization of the tissue distribution profile. Mol Pharm 2018, 15, (3), 934-946). Briefly, the PSMA ligand was administered at a specific activity of 50 MBq / nmol. 177 The radioligand was labeled with Lu and incubated with human plasma samples or PBS at room temperature. The free and plasma-bound fractions were separated using a Centrifree ultrafiltration device (4104 centrifugal filter unit; Millipore, nominal molecular weight limit 30,000 Da, methylcellulose micropartition membrane). The incubated solution was loaded onto the ultrafiltration device and centrifuged at 2500 rpm for 40 minutes at 20°C. Samples were taken from the filtrate and analyzed for radioactivity using a γ counter. The amount of radioligand bound to plasma was calculated as the ratio of the radioactivity measured in the filtrate to that in the corresponding loading solution (set at 100%). Experiments were performed at least three times for each radioligand.

[0238] The results are shown in Figure 7. 177 Lu-Ibu-PSMA, 177 Lu-Ibu-Dα-PSMA, 177 Lu-Ibu-Dβ-PSMA, 177 Lu-Ibu-N-PSMA, and 177 Ultrafiltration experiments with Lu-Ibu-DAB-PSMA demonstrated high serum protein binding, as evidenced by the fact that <11% of the radioligand penetrated the filter membrane when incubated in human plasma. The radioligand showed no retention by the filter membrane when incubated in PBS (protein-free). 177 Lu-Ibu-N-PSMA and 177Lu-Ibu-DAB-PSMA exhibited slightly reduced plasma protein binding properties compared to other ibuprofen-derivatized radioligands. Five exemplary PSMA binders 177 Both Lu-PSMA ligands exhibited only approximately 59% albumin-bound fraction. 177 Compared to Lu-PSMA-617, it showed increased binding to plasma proteins.

[0239] Example 7: In vitro cellular internalization study 177 Lu-Ibu-PSMA, 177 Lu-Ibu-Dα-PSMA, 177 Lu-Ibu-Dβ-PSMA, 177 Lu-Ibu-N-PSMA, and 177 Cellular uptake and internalization of Lu-Ibu-DAB-PSMA were investigated using PSMA-positive PC-3PIP and PSMA-negative PC-3flu tumor cells, kindly provided by Dr. Martin Pomper (John Hopkins Institutions, Baltimore, US; Eiber, M.; Fendler, WP; Rowe, SP; Calais, J.; Hofman, MS; Maurer, T.; Schwarzenboeck, SM; Kratowchil, C.; Herrmann, K.; Giesel, FL. Prostate-specific membrane antigen ligands for imaging and therapy. J Nucl Med 2017, 58, (Suppl 2), 67S-76S). Each radioligand was tested in three triplicate experiments with PC-3PIP tumor cells and one triplicate experiment with PC-3flu tumor cells.

[0240] The results are shown in Figure 8. The uptake of radioligand into PC-3PIP tumor cells was significantly higher after 2 or 4 hours of incubation. 177 It was comparable to Lu-PSMA-617 (Figure 8A). 177 Lu-Ibu-PSMA and 177The internalized fraction of Lu-Dβ-PSMA is in the same range. 177 Lu-Ibu-Dα-PSMA, 177 Lu-Ibu-N-PSMA, 177 Lu-Ibu-DAB-PSMA, and 177 The uptake of both radioligands in PC-3 flu tumor cells was <2% after 4 hours, indicating high PSMA-specific cellular uptake (Fig. 8B).

[0241] Example 8: In vivo biodistribution studies In vivo experiments were approved by the local veterinary department and performed in accordance with Swiss animal protection laws. Mice were obtained from Charles River Laboratories (Sulzfeld, Germany) at 5–6 weeks of age. Female athymic nude Balb / c mice were inoculated with PSMA-positive PC-3PIP cells (6 × 10 6 100 μL of Ca containing 100 cells 2+ / Mg 2+ Hank's balanced salt solution (HBSS)) on the right shoulder, and PSMA-negative PC-3flu cells (5 × 10 6 100 μL of HBSS Ca containing 100 μL of cells 2+ / Mg 2+ ) was subcutaneously inoculated into the left shoulder. Two weeks later, the tumors grew to approximately 80–300 mm, which was suitable for conducting biodistribution studies. 3 reached the size of

[0242] Biodistribution studies were performed 12-15 days after inoculation of PC-3PIP / flu tumor cells. 177 Lu-Ibu-PSMA, 177 Lu-Ibu-Dβ-PSMA, 177 Lu-Ibu-Dα-PSMA, 177 Lu-Ibu-N-PSMA, 177 Lu-Ibu-DAB-PSMA, and 177Lu-PSMA-617 was diluted in 0.9% NaCl containing 0.05% bovine serum albumin (BSA) to prevent adhesion to the vial and syringe materials. The radioligand was injected into the lateral tail vein in a volume of 100–200 μL. Mice were euthanized at various time points post-injection (pi). Selected tissues and organs were harvested, weighed, and measured using a γ-counter. Results were decay-corrected and presented as the percentage of injected radioactivity per gram of tissue mass (% IA / g) (Tables 3 and 4). Table 3: PC-3PIP / flu tumor-bearing mice 177 Lu-Ibu-PSMA, 177 Lu-Ibu-Dβ-PSMA, and 177 Biodistribution data of Lu-Ibu-Dα-PSMA. Mean ± SD (n = 3–6) from each group of mice. [Table 3] Table 4: PC-3PIP / flu tumor-bearing mice 177 Lu-Ibu-N-PSMA, 177 Lu-Ibu-DAB-PSMA, and 177 Biodistribution of Lu-PSMA-617. Mean ± SD (n = 3–6) values ​​from each group of mice. [Table 4]

[0243] Biodistribution data and tumor-to-background ratios are also shown in Figures 9 and 10, respectively.

[0244] PC-3PIP tumor uptake was enhanced by engineered peptides without additional amino acid-based spacer entities 177 Lu-Ibu-PSMA was the most rapid, reaching 81.3±6.28% IA / g at 4 hpi and slightly higher (86.8±18.0% IA / g) at 24 hpi. 177 Lu-Ibu-Dβ-PSMA, 177 Lu-Ibu-N-PSMA, and 177Lu-Ibu-DAB-PSMA showed similar accumulation (65-66% IA / g) in PC-3PIP tumors at 4 h.p.i., but differed in retention in tumor tissue. 177 Lu-Ibu-Dβ-PSMA significantly increased tumor uptake (106±9.70% IA / g). 177 Lu-Ibu-N-PSMA and 177 The radioactivity level was reduced in the case of Lu-Ibu-DAB-PSMA (52-58% IA / g). 177 In the case of Lu-Ibu-Dα-PSMA, high accumulation in the tumor was first observed after 24 hours (84.2±14.9% IA / g). The tumor uptake of all radioligands, including ibuprofen, was significantly higher than that of the prior art radioligand at 24 h.p.i. 177 The uptake in PC-3flu tumors (PSMA-negative) was significantly lower than that observed after injection of Lu-PSMA-617 (37.3 ± 5.80% IA / g). The uptake in PC-3flu tumors (PSMA-negative) was significantly lower than the blood concentrations observed after injection of all radioligands, supporting PSMA-mediated uptake.

[0245] 177 For Lu-Ibu-Dβ-PSMA, the highest blood radioactivity level (13.2 ± 1.15% IA / g) was detected at 4 h.p.i., whereas all other compounds showed lower radioactivity accumulation in the blood pool at this time point (2.33–5.96% IA / g). 177 Lu-Ibu-PSMA, 177 Lu-Ibu-Dα-PSMA, 177 Lu-Ibu-N-PSMA, and 177 Mice injected with Lu-Ibu-DAB-PSMA showed a rapid clearance of radioactivity from the blood, <0.6% IA / g after 24 hours. 177 Clearance of Lu-Ibu-Dβ-PSMA was slower and remained at ∼1.3% IA / g at this same time point.

[0246] Renal uptake is 177Lu-Ibu-DAB-PSMA showed the lowest renal uptake at both 4 and 24 h.p.i. (19.4±1.84% and 6.00±0.68% IA / g, respectively), whereas the other radioligands showed renal uptake of 27–33% IA / g at 4 h.p.i. 177 Lu-Ibu-N-PSMA showed the fastest renal clearance, 8.02 ± 1.13% IA / g at 24 h.p.i. 177 Radioactivity levels in all other tissues were below blood levels and decreased over time.

[0247] The tumor-to-blood ratio of accumulated radioactivity at 4 h.p.i. 177 Lu-Ibu-PSMA, 177 Lu-Ibu-Dα-PSMA, 177 Lu-Ibu-N-PSMA, and 177 After injection of Lu-Ibu-DAB-PSMA, the results were similar (14–23), 177 It was lower after injection of Lu-Ibu-Dβ-PSMA (5.03±0.73). At 24 h.p.i. 177 Lu-Ibu-DAB-PSMA (~337) had the highest tumor-to-blood ratio, followed by 177 Lu-Ibu-N-PSMA(~227), 177 Lu-Ibu-Dα-PSMA(~198), 177 Lu-Ibu-PSMA (~149), and 177 The tumor-to-kidney ratio was similar for all radioligands at 4 h.p.i. but differed by 2-fold at 24 h.p.i. 177 Lu-Ibu-DAB-PSMA and 177 The highest ratio was obtained after injection of Lu-Ibu-N-PSMA. The tumor-to-liver ratio at 24 h.p.i. was 177 Lu-Ibu-Dα-PSMA(196) and 177 The highest was Lu-Ibu-N-PSMA(182).

[0248] Example 9: In vivo whole body radioactivity measurements In vivo experiments were approved by the local veterinary department and performed in accordance with Swiss animal protection laws. Mice were obtained from Charles River Laboratories (Sulzfeld, Germany) at 5–6 weeks of age. Female athymic nude Balb / c mice were inoculated with PSMA-positive PC-3PIP cells (6 × 10 6 100 μL of Ca containing 100 cells 2+ / Mg 2+ Hank's balanced salt solution (HBSS)) on the right shoulder, and PSMA-negative PC-3flu cells (5 × 10 6 100 μL of HBSS Ca containing 100 μL of cells 2+ / Mg 2+ ) was subcutaneously inoculated into the left shoulder. Two weeks later, the tumors grew to approximately 80–300 mm, which was suitable for conducting biodistribution studies. 3 reached the size of

[0249] A single radioligand (specific activity: 30 MBq / nmol) was diluted in 0.05% bovine serum albumin (BSA) containing 0.9% NaCl and injected intravenously (IV) into PC-3PIP / flu tumor-bearing mice for SPECT / CT imaging (30 MBq, 1 nmol, 100 μL). Mice were dose calibrated at 4 h, 24 h, 48 h, and 72 h p.i. using a dose calibrator.

[0250] The results are shown in Figure 11. Whole-body measurements revealed distinct excretion patterns of the single radioligands, most pronounced at 4 hp.i. The body retention at 4 hp.i. 177 The highest was Lu-Ibu-Dβ-PSMA (49%). 177 Lu-Ibu-PSMA (33%), 177 Lu-Ibu-Dα-PSMA (29%), 177 lower with Lu-Ibu-DAB-PSMA (17%); 177 Lu-Ibu-N-PSMA (12%) shows the lowest body retention of radioactivity. Both radioligands have limited albumin binding properties. 177Lu-PSMA-617 (6.5%) showed higher radioactivity retention, but radioactivity retention was significantly lower with the comparative radioligands with albumin binders based on p-iodophenyl- and p-tolyl-entities instead of ibuprofen, respectively. 177 Lu-PSMA-ALB-53 (93%) and 177 The radioactivity retention in the body decreased over time with both ibuprofen-derivatized radioligands, reaching 72 h.p.i. at 12 h.p.i. (Umbricht, CA; Benesova, M.; Schibli, R.; Muller, C. Preclinical development of novel PSMA-targeting radioligands: modulation of albumin-binding properties to improve prostate cancer therapy. Mol Pharm 2018, Mol Pharm 2018, 15, (6), 2297-2306). 177 The retention rate reached a similar level to that of Lu-PSMA-617. 177 Lu-PSMA-ALB-53 and 177 Lu-PSMA-ALB-56 still showed 42% and 10% of radioactivity retained in the body, respectively.

[0251] Example 10: In vivo SPECT / CT imaging SPECT / CT images were acquired using a dedicated small-animal SPECT / CT scanner (NanoSPECT / CT™, Mediso Medical Imaging Systems, Budapest, Hungary). A 45-minute SPECT / CT scan was performed, followed by a 7.5-minute CT scan. During in vivo scanning, mice were anesthetized with a mixture of isoflurane and oxygen. Reconstruction of the acquired data was performed using HiSPECT software (version 1.4.3049, Scivis GmbH, Göttingen, Germany). All images were generated using VivoQuant postprocessing software (version 2.10, invicro Imaging Services and Software, Boston, USA). A Gaussian postreconstruction filter (FWHM = 1.0 mm) was applied to the images, and 5% of the lower scale was cut off, allowing visualization of the most important organs and tissues.

[0252] SPECT images are shown in Figure 12. SPECT images visualize high radioligand accumulation in the PC-3PIP tumor xenograft (right), while no radioactivity accumulation was observed in the PC-3flu tumor (left). At 4 hours, some radioactivity was observed in the kidney and, as a result of renal clearance, in the bladder.

[0253] Example 11: 177 In vitro evaluation of Lu-Ibu-sPSMA In this example, to investigate the potential effect of spacer length on the biodistribution profile of radioligands, a methylene linker ((CH2)2) shorter than the lysine side chain ((CH2)4) for spacer attachment in ibuprofen was evaluated. To this end, Ibu-sPSMA (the "s" stands for "short" spacer) was designed and synthesized (Example 8.2). Ibu-sPSMA was 177 It was radiolabeled with Lu and evaluated preclinically. 177The stability, albumin binding properties, and binding ability of Lu-Ibu-sPSMA to PSMA-positive PC-3PIP cells were investigated. Biodistribution and SPECT / CT imaging studies were performed using PC-3PIP / flu tumor-bearing mice. New data were 177 Data obtained using Lu-PSMA-617 and PSMA radioligand functionalized with ibuprofen or 177 The data were compared with those obtained with Lu-PSMA-ALB-56.

[0254] In vitro testing 177 Lu-Ibu-sPSMA was used. 177 Lu-PSMA-617 and, if necessary, 177 Results were compared with those previously obtained using Lu-PSMA-ALB-56 (Umbricht et al., Mol Pharm 2018, 15,(6):2297-2306). Labeling efficiency, n-octanol / PBS partition coefficient (logD value), and albumin binding studies were performed. Uptake and internalization experiments were performed using the PSMA-transfected, PSMA-positive PC-3PIP tumor cell line and the mock-transfected, PSMA-negative PC-3flu tumor cell line.

[0255] 11.1. Radioactive labels Ibu-sPSMA was diluted in a 3:1 (v / v) mixture of Milli-Q water / DMSO to a final concentration of 1 mM. Ibu-sPSMA was dissolved in a 1:5 (v / v) mixture of sodium acetate (0.5 M, pH 8) and HCl (0.05 M, pH 1). 177 Lu (0.05M HCl with no added carrier) 177 Ibu-sPSMA was labeled with 1000 u (Isotope Technologies Garching ITG GmbH, Germany) at pH 4.5 with specific activities ranging from 5 to 50 MBq / nmol, depending on the experiment being performed. 177 The reaction mixture was incubated at 95°C for 10 minutes and then loaded onto a C-18 reversed-phase column (Xterra TMQuality control was performed using an HPLC equipped with a MS, C18, 5 μm, 150 × 4.6 mm; Waters). The mobile phase consisted of Milli-Q water containing 0.1% trifluoroacetic acid (A) and acetonitrile (B), with a gradient from 95% A and 5% B to 20% A and 80% B over 15 min at a flow rate of 1.0 mL / min. The radioligand was diluted with Milli-Q water containing Na-DTPA (50 μM) before injection into the HPLC (Figure 14).

[0256] 11.2. Radiolytic stability The radiolytic stability over time was evaluated for Ibu-sPSMA in three independent experiments. For this purpose, Ibu-sPSMA was diluted in a volume of 120 μL at a specific activity of 50 MBq / nmol with or without the addition of L-ascorbic acid (3 mg). 177 The radioligand was labeled with Lu. After quality control using HPLC (t = 0, radiochemical purity ≥ 98%), the labeling solution was diluted with saline to 250 MBq / 500 μL and incubated at room temperature. The integrity of the radioligand was determined by HPLC after 1, 4, and 24 h of incubation, as previously reported (Siwowska et al., Mol. Pharmaceutical 2017, 14, (2), 523-532). The HPLC chromatograms showed the radiolabeled product, released 177 The peaks representing Lu and a degradation product of unknown structure were analyzed by integration (Figure 15). Quantitative evaluation was performed by expressing the peak area of ​​the intact product as a percentage of the sum of the integrated peak areas of the entire chromatogram.

[0257] 11.3. n-Octanol / PBS partition coefficient 177 The n-octanol / PBS partition coefficient of Lu-Ibu-sPSMA was measured according to the publication by Benesova, M. et al. Mol Pharm 2018, 15, (3), 934-946. 177 The value of Lu-Ibu-sPSMA was -2.43±0.01. The modification of the PSMA ligand by ibuprofen was177 compared to Lu-PSMA-617 (-4.38 ± 0.01), which affected the hydrophobic properties of the radioligand. 177 The hydrophilicity of Lu-Ibu-sPSMA is comparable to that of other ibuprofen-derivatized ligands and 177 This was in the same range as Lu-PSMA-ALB-56 (-2.9 ± 0.2).

[0258] 11.3. Albumin Binding Properties 177 The plasma protein binding properties of Lu-Ibu-sPSMA were determined using an ultrafiltration assay by Benesova, M. et al. Briefly, Ibu-sPSMA ligand was injected into the plasma at a molar irradiated radioactivity of 50 MBq / nmol. 177 The radioligand was labeled with Lu and incubated with human plasma samples or PBS at 37°C. Separation was performed using a Centrifree ultrafiltration device (4104 centrifugal filter unit; Millipore, nominal molecular weight limit 30,000 Da, methylcellulose micropartition membrane). The incubated solution was loaded into the ultrafiltration device and centrifuged at 2,000 rpm for 40 minutes at 20°C. Samples were taken from the filtrate and analyzed for radioactivity in a gamma counter. The amount of radioligand bound to plasma was calculated as the ratio of the radioactivity measured in the filtrate to that in the corresponding loading solution (set at 100%). Experiments were performed in triplicate.

[0259] 177 Ultrafiltration experiments with Lu-Ibu-sPSMA revealed high serum protein binding, as demonstrated by the fact that ∼97% of the radioligand was retained by the filter membrane after incubation in human plasma. The radioligand showed no retention by the filter membrane when incubated in (protein-free) PBS. 177 Lu-Ibu-sPSMA showed only approximately 59% albumin-bound fraction. 177 Compared to Lu-PSMA-617, it showed increased binding to plasma proteins (Figure 16).

[0260] 11.4. Cellular internalization assay 177 The cellular uptake and internalization of Lu-Ibu-sPSMA was investigated using PSMA-positive PC-3PIP and PSMA-negative PC-3flu tumor cells, kindly provided by Dr. Martin Pomper (Johns Hopkins University School of Medicine, Baltimore, MD, USA) (Eiber, et al.; J Nucl Med 2017, 58, (Suppl 2), 67S-76S). 177 Lu-Ibu-sPSMA was investigated in three experiments with six replicates using PC-3PIP tumor cells and in three experiments with six replicates using PC-3flu tumor cells.

[0261] 177 Uptake and internalization of Lu-Ibu-sPSMA into PC-3PIP tumor cells 177 It was slightly higher than Lu-PSMA-617 (Figure 17). 177 The internalized fraction of Lu-Ibu-sPSMA was 18% and 22% after 2 and 4 hours of incubation, respectively (Figure 17A). 177 The uptake of Lu-Ibu-sPSMA was <0.1% after 4 hours, indicating high PSMA-specific cellular uptake in PC-3PIP cells (FIG. 17B).

[0262] 11.5.K D Determining Values K indicating PSMA binding affinity of the novel radioligand D value was determined. 177 Lu-Ibu-sPSMA K D The values ​​are comparable to those of other ibuprofen-derivatized PSMA radioligands and were determined under the same experimental conditions. 177 Lu-PSMA-ALB-56 and 177 Lu-PSMA-617 D There was no substantial difference between the values ​​(Table 5). Table 5. K of PSMA radioligands D data. [Table 5]

[0263] Example 12: In vivo evaluation 177 Lu-Ibu-sPSMA was characterized in vivo. 177 Lu-PSMA-617 and 177 The data were compared with those obtained with Lu-PSMA-ALB-56.

[0264] 12.1. Tumor Mouse Models Mice were obtained from Charles River Laboratories (Sulzfeld, Germany) at 5–6 weeks of age. Female athymic nude Balb / c mice were inoculated with PSMA-positive PC-3PIP cells (6 × 10 6 100 μL of Hank's balanced salt solution (HBSS) containing 5 × 10 cells on the right shoulder, and PSMA-negative PC-3flu cells (5 × 10 6 100 μL of HBSS containing 100 μg of cells was inoculated subcutaneously into the left shoulder. Two weeks later, tumors grew to approximately 80–300 mm, suitable for performing biodistribution and imaging studies. 3 reached the size of

[0265] 12.2. Biodistribution studies Biodistribution studies were performed 12 to 15 days after PC-3PIP / flu tumor cell inoculation. 177 Lu-Ibu-sPSMA was diluted in 0.9% NaCl containing 0.05% bovine serum albumin (BSA) to prevent adhesion to the vial and syringe material. The radioligand was injected into the lateral tail vein in a volume of 100 μL. Mice were euthanized at various time points post-injection (pi). Selected tissues and organs were harvested, weighed, and measured using a γ-counter. Results were decay-corrected and presented as the percentage of injected radioactivity per gram of tissue mass (% IA / g) (Table 6, Figure 18).

[0266] 177Lu-Ibu-sPSMA showed high accumulation in PC-3PIP tumors (63 ± 8% IA / g) already 1 hour post-injection. This further increased by 24 hpi to the highest tumor uptake of all ibuprofen-containing radioligands observed (132 ± 15% IA / g). Clearance of radioactivity from tumor tissue was slow, with 57 ± 9% IA / g radioactivity retained in tumors by day 4 post-injection, compared with 20–34% IA / g for other radioligands at the same time points. Uptake into PSMA-negative PC-3flu cells was significantly below blood levels, confirming specific PSMA-mediated uptake in PC-3PIP tumors.

[0267] 177 Lu-Ibu-sPSMA showed the highest blood radioactivity levels (29 ± 4% IA / g compared to 13–18% IA / g for other ibuprofen-containing radioligands) at 1 h.p.i. This continuously decreased over time, reaching 4 days post-injection. 177 Lu-Ibu-PSMA and 177 The blood radioactivity level decreased to the same level as Lu-Ibu-Dα-PSMA. 177 Lu-Ibu-N-PSMA and 177 Compared with the blood radioactivity level of Lu-Ibu-DAB-PSMA, 177 Lu-Ibu-sPSMA showed approximately three-fold higher levels at 24 and 96 hours after injection.

[0268] 177 Lu-Ibu-PSMA, 177 Lu-Ibu-N-PSMA, 177 Lu-Ibu-DAB-PSMA was only 30–33% IA / g; 177Renal uptake was very high at 1 hp.i. (114 ± 15% IA / g) compared with 73 ± 2% IA / g for Lu-Ibu-Dα-PSMA. However, due to rapid renal clearance, radioactivity levels comparable to those of other radioligands were already reached by 4 hp.i. Similarly, the liver showed high radioactivity accumulation at early time points (17 ± 4% IA / g at 1 hp.i. and 7.2 ± 0.5% IA / g at 4 hp.i.), but rapid clearance resulted in similar levels of radioactivity retention in the liver at 24 and 96 hp.i. compared with other ibuprofen-containing radioligands.

[0269] Table 6 shows the results of the immunization in PC-3PIP / flu tumor-bearing mice. 177 Biodistribution data for Lu-Ibu-sPSMA are shown. Each value represents the mean ± SD of the percentage of injected radioactivity per gram of tissue [% IA / g] from each group of mice (n=4). 177 Comparison of the characteristics of Lu-Ibu-sPSMA with other ibuprofen-derivatized radioligands revealed significantly higher accumulation and retention of activity in PSMA-positive PC-3PIP tumors, with high tumor-to-kidney and tumor-to-liver ratios, especially at later time points. [Table 6]

[0270] Due to high blood radioactivity levels, especially at early time points after injection, 177 The tumor-to-blood ratio of accumulated radioactivity in Lu-Ibu-sPSMA was 177 was consistently lower compared with Lu-Ibu-DAB-PSMA, but at later time points. 177 Lu-Ibu-PSMA, 177 Lu-Ibu-Dα-PSMA, and 177 Similar values ​​were reached as with Lu-Ibu-N-PSMA (Figure 19A). 177 The tumor-to-kidney ratio of Lu-Ibu-sPSMA was 1 hpi 177Although the ratios were similarly low compared to Lu-Ibu-Dα-PSMA (0.56 ± 0.09 and 0.59 ± 0.08, respectively), they increased significantly over time, resulting in the highest ratios among the radioligands at any other time point (Figure 19B). Similarly, tumor-to-liver ratios were low at 1 and 4 hp.i., but exceeded those of the other radioligands at 24 and 96 h postinjection (Figure 19C).

[0271] 12.3.Whole body radioactivity measurement Each albumin-bound radioligand (molar activity: 25 MBq / nmol) was diluted in 0.9% NaCl containing 0.05% BSA and injected intravenously (25 MBq, 1 nmol, 100 μL) into non-tumor-bearing mice. Mice were monitored with a dose calibrator at various time points up to 56 h.p.i. Each radioligand was 177 This was compared with previously obtained data from Lu-PSMA-617.

[0272] Whole-body measurements revealed distinct excretion patterns for the single radioligands, most evident at early time points up to 8 hours post-injection (Figure 20). Of all radioligands, body retention was consistent with the exception of late time points (48 hp.i. and 56 hp.i.). 177 Lu-Ibu-Dβ-PSMA was the most potent, containing p-iodophenyl as a stronger albumin binder. 177 Lu-PSMA-ALB-56 was also relatively high. Other ibuprofen-containing radioligands 177 It was shown that the retention in the body is lower compared to Lu-PSMA-ALB-56. 177 Lu-Ibu-DAB-PSMA was characterized by the fastest elimination pattern, retaining only 18% of its radioactivity already 4 hours after injection, compared to other albumin-binding radioligands (35–73%). All radioligands have limited albumin binding properties. 177 Lu-PSMA-617 showed higher radioactivity retention than Lu-PSMA-617. In both cases, radioactivity retention in the body decreased over time, reaching similar retention rates at 32 h.p.i.

[0273] 12.4. In vivo SPECT / CT imaging SPECT / CT images were acquired using a dedicated small-animal SPECT / CT scanner (NanoSPECT / CT™, Mediso Medical Imaging Systems, Budapest, Hungary). A 45-minute SPECT / CT scan was performed, followed by a 7.5-minute CT scan. During in vivo scanning, mice were anesthetized with a mixture of isoflurane and oxygen. Reconstruction of the acquired data was performed using HiSPECT software (version 1.4.3049, Scivis GmbH, Göttingen, Germany). All images were generated using VivoQuant postprocessing software (version 2.10, invicro Imaging Services and Software, Boston, USA). A Gaussian postreconstruction filter (FWHM = 1.0 mm) was applied to the images, and 5% of the lower scale was cut off, allowing visualization of the most important organs and tissues.

[0274] SPECT / CT images are 177 High Lu-Ibu-sPSMA accumulation was visualized in PC-3PIP tumor xenografts (right side of Figure 21), but no radioactivity accumulation was observed in PC-3flu tumors (left side of Figure 21). At 4 hours, some radioactivity was observed in the kidney and, as a result of renal clearance, in the bladder. At 24 hours, radioactivity was visualized only in PC-3PIP tumors (Figure 21).

[0275] Example 13. In vivo therapeutic testing 177 The therapeutic efficacy of Lu-Ibu-DAB-PSMA was evaluated in vivo in a tumor mouse model (PSMA-positive PC-3PIP tumor-bearing mice). 177 Lu-PSMA-617 and 177This was compared with data obtained with Lu-PSMA-ALB-56 (Eiber et al., J. Nucl. Med., 2017, 58 (Suppl. 2) 67S-76S).

[0276] 13.1. Tumor Mouse Models Mice were obtained from Charles River Laboratories (Sulzfeld, Germany) at 5–6 weeks of age. Female athymic nude Balb / c mice were inoculated with PSMA-positive PC-3PIP cells (4 × 10 6 100 μL of Hank's Balanced Salt Solution (HBSS) containing 100 μL of cells was inoculated subcutaneously into the right shoulder. After 6 days, tumors grew to approximately 30–160 mm, suitable for conducting in vivo therapeutic studies. 3 Mice were euthanized when predefined endpoint criteria were reached or when the study was completed at day 84. Endpoint criteria were: (i) weight loss >15%; (ii) tumor volume >800 mm 3 , (iii) >10% weight loss and >700 mm 3 or (iv) symptoms of anxiety and pain, or a combination thereof.

[0277] 13.2. Method 4×10 6 Six days after subcutaneous inoculation of PC-3PIP tumor cells, three groups with statistically similar body weights and tumor volumes were injected intravenously. One group was injected with vehicle only (saline containing 0.05% bovine serum albumin (BSA); Group A; n=6), and the other two groups were injected with 0.05% bovine serum albumin (BSA) in saline on day 0 of the treatment study. 177 Lu-Ibu-DAB-PSMA (Group B: 2MBq, 1nmol (n=6) and Group C: 5MBq, 1nmol (n=6)) was injected (Table 7). Mice monitoring and evaluation of the therapeutic study were performed as described by Eiber et al., J. Nucl. Med., 2017, 58 (Suppl. 2) 67S-76S. Briefly, mice were monitored by measuring body weight and tumor size every 2 days for 12 weeks. Relative body weight (RBW) was calculated as [BW x / BW0], and BWx where BW is the body weight (grams) on a given day x, and BW is the body weight (grams) on day 0. Tumor dimensions were determined by measuring the longest tumor axis (L) and its perpendicular axis (W) using digital calipers. Tumor volume (V) was calculated using the formula [V = 0.5 × (LW 2 Relative tumor volume (RTV) was calculated according to [TV x / TV0] and TV x is the tumor volume (mm ) on a given day x. 3 ), and TV0 is the tumor volume on day 0 (mm 3 ) Table 7. Treatment trial design [Table 7] a There was no significant difference between the values ​​measured in each group (p>0.05).

[0278] The effectiveness of radionuclide therapy is measured by tumor growth delay (TGD) x ) and was calculated as the time required for the tumor volume to increase to x times the initial volume on day 0. x =TGD x (T) / TGD x (C)] shows a 5-fold increase in initial tumor volume (x=5, TGD5) compared with TGD1 in control mice (C). x TGD of treated mice (T) relative to the mean x The median survival time was calculated using GraphPad Prism software (version 7). The survival rate of mice was evaluated using Kaplan-Meier curves, and the median survival time of mice in each group was determined using GraphPad Prism software (version 7).

[0279] 13.3. Results of Treatment Trials The results of the treatment study were divided into a group injected with vehicle only (0.05% BSA in saline; Group A; n=6), 177 groups injected with Lu-PSMA-617 (2MBq and 5MBq; Groups D and E, n = 6); and 177Combined with the results obtained in a treatment study involving Lu-PSMA-ALB-56 (2 MBq and 5 MBq; Groups F and G; n=6) (Eiber et al., J. Nucl. Med., 2017, 58 (Suppl. 2) 67S-76S), tumor growth in treated mice was slower than that in untreated control mice (total; n=12) (Figure 22).

[0280] 2MBq 177 Lu-Ibu-DAB-PSMA(1.6) and 177 The tumor growth retardation index 5 (TGDI5) values ​​of the group injected with Lu-PSMA-ALB-56 (1.8) were significantly elevated compared to the control animals (defined as 1.0 for control). 177 Only TGDI5 in mice injected with Lu-PSMA-617(1.1) was comparable to the values ​​in control animals (Table 8). Table 8. Tumor growth delay index for a 5-fold increase in tumor size [Table 8] a nd = not defined as many mice survived the test.

[0281] 5MBq 177 TGDI5 levels in each group injected with Lu-PSMA-617(2.0) were similar to those obtained with the albumin-bound radioligand administered at 2 MBq per mouse. 177 Lu-Ibu-DAB-PSMA or 177 TGDI5 levels were not defined for mice injected with Lu-PSMA-ALB-56 because tumors completely disappeared in four mice in each group. Tumor regrowth in animals that showed complete remission was not observed until the end of the study on day 84. In each group, tumor regrowth was observed in two mice approximately 5 weeks after treatment, and on days 70 and 82 ( 177 Lu-Ibu-DAB-PSMA) and days 58 and 68 ( 177 The endpoint was reached in the 5-MBq group (Lu-PSMA-ALB-56).177 Lu-Ibu-DAB-PSMA or 5MBq 177 The results remained undefined in the groups of mice administered Lu-PSMA-ALB-56 (Figure 23). At the end of the study on day 84, four mice were still alive in each of these groups. 177 Lu-Ibu-DAB-PSMA and 177 The median survival times of mice treated with Lu-PSMA-ALB-56 were 34 and 36 days, respectively, which were significantly longer than the median survival time of control mice (26 days). 177 The median survival time of the group injected with Lu-PSMA-617 (19 days) was shorter than any other group, including untreated control mice (Figure 23).

[0282] On day 16, the first control mice reached endpoint, but mean relative body weights (0.93-1.10) were similar in all groups (Figure 24). At the time of euthanasia, 5MBq 177 Lu-Ibu-DAB-PSMA(1.06±0.10) and 177 The mean relative body weight of each of the groups injected with Lu-PSMA-ALB-56 (1.20 ± 0.14) was 1.01 ± 0.05 compared with that of control mice (0.88 ± 0.05). 177 The mean relative body weight of the Lu-PSMA-617-treated mice (0.86 ± 0.05) was increased compared to that of the control mice and 177 Faster tumor growth in mice treated with Lu-PSMA-617, and therefore 177 Lu-Ibu-DAB-PSMA or 177 This may be due to the fact that the endpoint was reached earlier than in mice treated with Lu-PSMA-ALB-56 (Figure 24).

[0283] As a result, 177 Lu-Ibu-DAB-PSMA was effective at both injected radioactivity doses (2MBq / mouse and 5MBq / mouse, respectively). 177 It performed significantly better than Lu-PSMA-617. 177Lu-Ibu-DAB-PSMA has a low injected radioactivity (2MBq / mouse) 177 It was only slightly inferior to Lu-PSMA-ALB-56, but was even slightly superior when applied at a higher radioactivity dose (5 MBq / mouse). 177 Compared with the results obtained with Lu-PSMA-ALB-56 and the results of this treatment trial, 177 The improved tumor-to-blood ratio of Lu-Ibu-DAB-PSMA was significantly higher than that of existing 177 than Lu-PSMA-617 177 This confirms the superiority of Lu-Ibu-DAB-PSMA.

Claims

1. Formula (7)(e) or (7)(e)′: 【Chemistry 18】 wherein D is a chelator, or a pharmaceutically acceptable salt, solvate, or radiolabeled complex of said compound.

2. A radiolabeled complex in which a radionuclide is complexed as a radiolabel, wherein the radiolabel is 94Tc, 99mTc, 90In, 111In, 67Ga, 68Ga, 86Y, 90Y, 177Lu, 151Tb, 186Re, 188Re, 64Cu, 67Cu, 55Co, 57Co, 43Sc, 44Sc, 47Sc, 225Ac, 213Bi, 212Bi, 212Pb, 227Th, 153Sm, 166Ho, 152Gd, 153Gd, 157Gd, or 166 Dy.

3. The compound according to claim 2, wherein the radioactive label is 177 Lu.

4. A tumor antigen targeting agent comprising a compound described in any one of claims 1 to 3, characterized in that the compound selectively binds to a tumor antigen and targets cells or tissues expressing the tumor antigen.

5. A tumor antigen targeting agent as described in claim 4, wherein the compound contains a radioactive nuclide as a radioactive label.

6. A tumor antigen targeting agent described in claim 4 or 5, which is used as at least one of a cancer diagnostic agent, a cancer therapeutic agent, a cancer preventive agent, or a precursor thereof.

7. A compound according to any one of claims 1 to 3 or a tumor antigen targeting agent according to any one of claims 4 to 6, A pharmaceutical composition comprising at least one of a pharmaceutically acceptable carrier, a diluent, and an excipient.

8. A compound according to any one of claims 1 to 3 or a tumor antigen targeting agent according to any one of claims 4 to 6, A cancer diagnostic agent or a cancer therapeutic agent, comprising at least one of a pharmaceutically acceptable carrier, a diluent, and an excipient.

9. A kit comprising any one of a compound described in any one of claims 1 to 3, a tumor antigen targeting agent described in any one of claims 4 to 6, a pharmaceutical composition described in claim 7, and a cancer diagnostic agent or cancer therapeutic agent described in claim 8.

10. The kit according to claim 9, which is a pharmaceutical and / or diagnostic kit used as a pharmaceutical and / or diagnostic agent.

11. A tumor antigen targeting agent described in any of claims 4 to 6, a pharmaceutical composition described in claim 7, a cancer diagnostic or therapeutic agent described in claim 8, or a kit described in claim 9, used in a method for detecting the presence of cells and / or tissues expressing prostate-specific membrane antigen (PSMA).

12. A tumor antigen targeting agent according to any one of claims 4 to 6, a pharmaceutical composition according to claim 7, a cancer diagnostic or therapeutic drug according to claim 8, or a kit according to claim 10, for use in a method for diagnosing, treating, and / or preventing prostate cancer, pancreatic cancer, kidney cancer, or bladder cancer.

13. A tumor antigen targeting agent described in any one of claims 4 to 6, a pharmaceutical composition described in claim 7, a cancer diagnostic or therapeutic agent described in claim 8, or a kit described in claim 10, for use in a method comprising administering the agent to a patient and obtaining a radiological image from the patient.

14. An in vitro method for detecting the presence of cells and / or tissues expressing prostate-specific membrane antigen (PSMA), comprising: (a) contacting a cell and / or tissue with the tumor antigen targeting agent according to any one of claims 4 to 6, the pharmaceutical composition according to claim 7, the cancer diagnostic or therapeutic agent according to claim 8, or the kit according to claim 10; (b) applying a detection means to detect cells and / or tissues that express PSMA.

15. The in vitro method of claim 14, wherein the detection means is radiation imaging including positron emission tomography (PET) or single photon emission computed tomography (SPECT).

16. An in vitro method according to any one of claims 14 to 15, wherein the cells and / or tissues include prostate cells and / or tissues, spleen cells and / or tissues, or kidney cells and / or tissues.

17. An in vitro method described in any of claims 14 to 16, wherein the presence of PSMA-expressing cells or tissue is indicative of prostate tumor, metastatic prostate tumor, renal tumor, pancreatic tumor, bladder tumor, and combinations thereof.

18. A compound characterized by formula (7)(e) or (7)(e)' as defined in claim 1, or a pharmaceutically acceptable salt or solvate of said compound; A method for preparing a radiolabeled complex using a radionuclide.

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