WO2021175147A1 - Prostate-specific membrane antigen-binding ligand conjugate and application thereof - Google Patents

Abstract

A prostate-specific membrane antigen (PSMA)-binding ligand conjugate and an application thereof. Specifically, a conjugate as shown in formula I: Y1-L1-Z1 (I), wherein Y1 is a chelate moiety, Z1 is a PSMA-binding ligand moiety, and L1 is a linking group for linking the Z1 to the Y1. A labelled compound comprising the conjugate and use of the labelled compound for preparing a developer or therapeutic drug for diagnosing and treating the prostatic cancer.

Description

Prostate specific membrane antigen binding ligand conjugate and its application Technical field

The invention belongs to the medical field, and specifically relates to a conjugate for prostate specific membrane antigen binding ligand and its application.

Background technique

Prostate cancer (Pca) is one of the most important cancers. Every year, more than one million men are diagnosed with prostate cancer. Conventional cancer treatments include surgery, radiotherapy, chemotherapy, and hormone therapy. However, there is still a lack of effective treatment methods for recurrent, metastatic, and hormone therapy-independent prostate cancer.

Prostate-specific membrane antigen (PSMA) is a transmembrane glycoprotein that has abundant but specific expression on the surface of prostate cancer, especially in androgen-independent, advanced and metastatic diseases. Another advantage of PSMA as a nuclear medicine diagnosis and treatment target is that it has a relatively large extracellular domain. A variety of PSMA-targeted radiotracers and radiopharmaceutical treatments have entered clinical trials for clinical diagnostic imaging and the treatment of metastatic castration resistant prostate cancer (mCRPC).

PSMA-11 ^{combined with 68} Ga is currently the most effective PSMA targeted imaging ligand. Other ligands, including PSMA-617 and PSMA-I&T combined with ¹⁷⁷ Lu, ²¹³ Bi or ²²⁵ Ac, have also shown good results in PSMA targeted therapy. Effect. Although radiolabeled PSMA ligands have excellent in vivo characteristics in clinical diagnostic imaging, current therapeutic PSMA ligands have a short biological half-life, high renal toxicity, and a very low complete remission rate, and there are still 30% after treatment. % Of patients have disease progression.

In summary, the field urgently needs to develop more effective new PSMA ligands with lower renal toxicity and longer biological half-life.

Summary of the invention

The purpose of the present invention is to provide a conjugate formed by coupling different linking groups and chelating compounds and PSMA binding ligands, which can selectively target cancer cells while increasing the distribution of drugs in the body and reducing toxicity Risks provide a safer new option for PSMA targeted radiopharmaceutical therapy.

In the first aspect of the present invention, a conjugate is provided, wherein the conjugate is shown in formula I

Y1-L1-Z1(I)

in,

(i) Y1 is the chelate part;

(ii) Z1 is the PSMA binding ligand part as shown in formula III;

Wherein, R ^{1 is} each independently selected from the following group: -COOH, -SO ₂ H, -CO ₃ H, -CO ₄ H, -PO ₂ H, -PO ₃ H, and -PO ₄ H ₂ ; and

(iii) L1 is a linker for connecting said Z1 and said Y1, and the connection mode of said linker with said Y1 and said Z1 is covalent connection; and

L1 consists of two or more structural units selected from the following group:

Amino acid residues, -NR ³ -L2-NR ³ -, -NR ³ -L2-CO-, -CO-L2-NR ³ -, C1-C8 alkylene;

R is selected from the following group: substituted or unsubstituted -C1-C4 alkylene-C6-C10 aryl, substituted or unsubstituted -C1-C4 alkylene-5 to 10-membered heteroaryl; wherein, the Heteroaryl groups contain 1 to 5 (preferably, 1, 2 or 3) heteroatoms selected from O, S and N; the substitution refers to one or more of the groups (preferably, 1, 2, or 3) hydrogen is substituted by a substituent selected from the group consisting of C1-C4 alkyl, phenyl, one or more (preferably 1, 2 or 3) C1-C4 alkyl的phenyl;

L2 is a C1-C8 alkylene group that is unsubstituted or substituted by one or more (preferably, 1, 2 or 3) R ^2;

R ^{2 is} each independently selected from the group consisting of C1-C4 alkyl, -COOH, -C(O)N(R ³ ) ₂ , -COO-C1-C4 alkyl; and

R ^{3 is} selected from the group consisting of H, C1-C4 alkyl.

In another preferred embodiment, the amino acid residue is derived from a natural amino acid or an unnatural amino acid.

In another preferred embodiment, the amino acid residues are derived from D-type and/or L-type amino acids.

In another preferred embodiment, the amino acid residues are derived from D-type and/or L-type amino acids.

In another preferred example, the amino acid residue is a residue derived from the group of amino acids selected from the group consisting of Ala(A), Arg(R), Asn(N), Asp(D), Cys(C), Gln( Q), Glu(E), Gly(G), His(H), Ile(I), Leu(L), Lys(K), Met(M), Phe(F), Pro(P), Ser( S), Thr(T), Trp(W), Tyr(Y), Val(V);

In another preferred embodiment, the amino acid residue is ^{-NH-CH (R a) -CO-} , and R ^a is selected from: H, C1-C6 alkyl group (preferably, - (CH _{2) 3} - CH ₃ , -CH(CH ₃ ) ₂ ), C1-C4 alkylene-S-C1-C4 alkyl (preferably, -(CH ₂ ) ₂ -S-CH ₃ ), C1-C4 alkylene Group-O-C1-C4 alkyl.

In another preferred example, R is selected from the following group: substituted or unsubstituted -(CH ₂ )-C6-C10 aryl, substituted or unsubstituted -(CH ₂ )-5 to 10-membered heteroaryl.

In another preferred example, R is selected from the following group:

In another preferred example, at least one structural unit of L1 is

L1 has only one structural unit

In another preferred example, at least one structural unit of L1 is

L1 has only one structural unit

In another preferred example, L1 also has a structural unit

In another preferred embodiment, L1 is a linking group as shown in formula IV;

-(A ¹ ) _n1 -A ^a -(A ² ) _n2 -A ^b -(A ³ ) _n3 -* (IV)

in,

* Indicates the end connected to Z1;

A ^a is

And A ^b is

Or A ^a is

And A ^b is

A ¹ , A ² and A ³ are each independently a structural unit selected from the following group:

Amino acid residues, -NR ³ -L2-NR ³ -, -NR ³ -L2-CO-, C1-C8 alkylene;

L2, R and R ^{3 are} as defined above;

n1, n2, and n3 are each independently an integer from 0 to 20; and n1, n2, and n3 are not 0 at the same time.

In another preferred example, n2=0.

In another preferred example, n3=0.

In another preferred example, n1=1, 3, 4, 5, 6, 7, 8, 9 or 10.

In another preferred embodiment, L1 is a linking group as shown in formula IVa;

-(A ¹ ) _n1 -A ^a -A ^b -* (IVa)

Among them, * represents the end connected to Z1; and A ^a is

And A ^b is

In another preferred example, L1 is a linking group shown in formula IVb,

Among them, * means one end connected to Z1;

The ^{definition of L 3} is the same as that of L2;

A ⁴ is an amino acid residue or -NR ³ -L2-CO-; and n4 = 0, 1, 2, 3, 4, 5, 6, or 7.

In another preferred embodiment, L ^{3 is} selected from:

-(CH ₂ ) _m -; where m=1, 2, 3, 4, 5 or 6.

In another preferred embodiment, A ⁴ is an amino acid residue.

In another preferred embodiment, A ⁴ is ^{-NH-CH (R a) -CO-} ; wherein, R ^a is selected from: H, C1-C6 alkyl group _{(preferably, (CH 2) 3 -CH 3} , -CH(CH ₃ ) ₂ ), C1-C4 alkylene-S-C1-C4 alkyl (preferably, -(CH ₂ ) ₂ -S-CH ₃ ), C1-C4 alkylene-O -C1-C4 alkyl.

In another preferred example, L1 is a linking group shown in formula IVc:

In another preferred example, L1 is the corresponding linking group in the compound in Table A, Table B1, Table B2, Table C1, and Table C2.

In another preferred example, Y1 is a monovalent group derived from DOTAGA.

In another preferred embodiment, Y1 is as shown in formula II;

In another preferred embodiment, Z1 is as shown in formula IIIa;

In another preferred embodiment, Z1 is as shown in formula IIIb,

In another preferred embodiment, the conjugate is selected from Table A, Table B1, Table B2, Table C1 and Table C2.

In the second aspect of the present invention, the use of the compound as described in the first aspect in the preparation of a labeled compound is provided.

In another preferred embodiment, the labeled compound is used for in vivo imaging or in vivo radiotherapy of a subject, for diagnosis or treatment of prostate cancer and/or its metastasis.

In the third aspect of the present invention, a labeling compound is provided, wherein the labeling compound includes the conjugate as described in the first aspect, and a label connected to or combined with or complexed or chelated with the conjugate.

In another preferred embodiment, the label is a detectable label.

In another preferred embodiment, the label is an isotope.

In another preferred embodiment, the isotopes are selected from the group consisting of diagnostic isotopes, therapeutic isotopes, or a combination thereof.

In another preferred embodiment, the diagnostic isotopes are selected from the following group: Tc-99m, Ga-68, F-18, I-123, I-125, I-131, In-111, Ga-67, Cu-64, Zr-89, C-11, Lu-177, Re-188, or a combination thereof.

In another preferred embodiment, the therapeutic isotope is selected from the group consisting of Lu-177, Y-90, Ac-225, As-211, Bi-212, Bi-213, Cs-137, Cr-51, Co-60, Dy-165, Er-169, Fm-255, Au-198, Ho-166, I-125, I-131, Ir-192, Fe-59, Pb-212, Mo-99, Pd- 103, P-32, K-42, Re-186, Re-188, Sm-153, Ra223, Ru-106, Na24, Sr89, Tb-149, Th-227, Xe-133Yb-169, Yb-177, Or a combination.

In another preferred example, the label is connected to or combined with or complexed or chelated with the Y1 part of the conjugate of formula I.

In another preferred example, the label is connected to or combined with the Y1 part of the conjugate of formula I or is complexed or chelated to form the structure shown in formula V;

Among them, M represents a marker.

In the fourth aspect of the present invention, a composition is provided, wherein the composition includes the conjugate as described in the first aspect or the labeled compound as described in the third aspect.

In another preferred embodiment, the composition further includes a pharmaceutically acceptable carrier.

In the fifth aspect of the present invention, there is provided a use of the conjugate according to the first aspect or the labeled compound according to the third aspect in the preparation of imaging agents and/or radiotherapeutics and/or diagnostic agents .

In the sixth aspect of the present invention, there is provided a conjugate as described in the first aspect or a labeled compound as described in the third aspect in the preparation of a medicament for the diagnosis and/or treatment of prostate cancer and/or its metastasis In the use.

In another preferred embodiment, the diagnosis includes staging and screening of suitable patients for targeted internal boils.

It should be understood that within the scope of the present invention, the above-mentioned technical features of the present invention and the technical features specifically described in the following (such as the embodiments) can be combined with each other to form a new or preferred technical solution. Due to space limitations, I will not repeat them one by one here.

Description of the drawings

Figure 1A shows the structure of compound 1 (upper image) and its RP-HPLC and ion chromatography detection results (neutralized lower image).

Figure 1B shows the structure of compound 2 (upper image) and its RP-HPLC and ion chromatography detection results (neutralized lower image).

Figure 1C shows the structure of compound 3 (upper image) and its RP-HPLC and ion chromatography detection results (neutralized lower image).

Figure 1D shows the structure of compound 4 (upper image) and its RP-HPLC and ion chromatography detection results (neutralized lower image).

Figure 1E shows the structure of compound 5 (upper image) and its RP-HPLC and ion chromatography detection results (neutralized lower image).

Detailed ways

The inventor has gone through extensive and in-depth research. A conjugate with a novel structure as shown in formula I was developed for the first time. The special structure of the conjugate (especially the linking group that connects the PSMA binding ligand and the chelate) makes the conjugate less nephrotoxic and longer than the existing PSMA binding ligand conjugate. The biological half-life, excellent blood circulation in the body, low kidney radiation dose, higher tumor radioactivity accumulation and absorption, and excellent tumor growth inhibition ability. Based on this, the inventor completed the present invention.

the term

As used herein, "C1-C6 alkyl" refers to a straight-chain or branched alkyl group including 1-6 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl , Tert-butyl, or similar groups.

As used herein, "C1-C6 alkoxy" includes linear or branched alkoxy groups of 1 to 6 carbon atoms. For example, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tert-butoxy, or similar groups.

Unless otherwise stated, the term "aryl" means a polyunsaturated (usually aromatic) hydrocarbon group, which may be a single ring or multiple rings (up to three rings) fused together or covalently linked. The term "heteroaryl" refers to an aryl group (or ring) containing 1 to 5 heteroatoms selected from N, O, and S, wherein nitrogen and sulfur atoms are optionally oxidized, and nitrogen atoms are optionally quaternized . Heteroaryl groups can be attached to the rest of the molecule through heteroatoms. Non-limiting examples of aryl groups include phenyl, naphthyl, and biphenyl, while non-limiting examples of heteroaryl groups include pyridyl, pyridazinyl, pyrazinyl, pyrimidinyl, triazinyl, quinolinyl, Quinoxalinyl, quinazolinyl, cinnoline, phthalazinyl, benzotriazinyl, purinyl, benzimidazolyl, benzopyrazolyl, benzotriazolyl, benziso Oxazolyl, isobenzofuryl, isoindolyl, indolizinyl, benzotriazinyl, thienopyridyl, thienopyrimidinyl, pyrazolopyrimidinyl, imidazopyridine, benzene And thiazolyl, benzofuranyl, benzothienyl, indolyl, quinolinyl, isoquinolinyl, isothiazolyl, pyrazolyl, indazolyl, pterridinyl, imidazolyl, triazolyl, Tetrazolyl, oxazolyl, isoxazolyl, thiadiazolyl, pyrrolyl, thiazolyl, furyl, thienyl and the like. The respective substituents of the above aryl and heteroaryl ring systems are selected from the group of acceptable substituents described below.

The term "alkylene" by itself or as part of another substituent refers to a divalent group derived from an alkane, such as -CH ₂ CH ₂ CH ₂ CH ₂ -.

Unless otherwise defined, herein, amino acids include natural amino acids or unnatural amino acids, including D-type and/or L-type amino acids. Examples of amino acids include, but are not limited to, Ala(A), Arg(R), Asn(N), Asp(D), Cys(C), Gln(Q), Glu(E), Gly(G), His(H ), Ile(I), Leu(L), Lys(K), Met(M), Phe(F), Pro(P), Ser(S), Thr(T), Trp(W), Tyr(Y ), Val(V). Preferably, in this context, the amino acid is an amino acid selected from the group consisting of L-glycine (L-Gly), L-alanine (L-Ala), β-alanine (β-Ala), L-glutamate Amino acid (L-Glu), L-aspartic acid (L-Asp), L-histidine (L-His), L-arginine (L-Arg), L-lysine (L- Lys), L-valine (L-Val), L-serine (L-Ser), L-threonine (L-Thr).

As used herein, the term "amino acid residue" refers to _{a group formed by removing one H from the N-terminal -NH 2 of} an amino acid and removing -OH from the C-terminal -COOH. The amino acid residues can be derived from natural amino acids or unnatural amino acids, and can be derived from D-type and/or L-type amino acid residues.

As used herein, the term "heteroatom" is intended to include oxygen (O), nitrogen (N), sulfur (S), and silicon (Si).

Unless otherwise specified, in the present invention, all compounds appearing are intended to include all possible optical isomers, such as a single chiral compound, or a mixture of various different chiral compounds (ie, racemates). In all the compounds of the present invention, each chiral carbon atom may optionally be R configuration or S configuration, or a mixture of R configuration and S configuration.

As used herein, renal brushboarder membrane enzyme refers to a group of enzymes that bind to the brush border of microvillous membrane. These enzymes include but are not limited to: alkaline phosphatase ( ALP), leucine aminopeptidase (LAP), γ-glutamyltransferase (y-GT), carboxypeptidase M.

Conjugate

The present invention provides a PSMA radioligand conjugate with a novel structure, which is modified for the PSMA radioligand so that the conjugate itself can be used as an albumin binder to bind albumin (albumin) to Increase the half-life of the conjugate of the invention. In addition, the conjugate is also modified with a linker cleavable by renal brush border enzymes, so that the conjugate can be degraded in the kidney and therefore has lower renal toxicity. Therefore, the conjugate with a novel structure provided by the present invention effectively enhances the in vivo blood circulation of the PSMA radioligand and reduces the renal radiation dose, has a positive impact on the overall movement characteristics of the drug, increases the accumulation of tumor radioactivity, and improves the therapeutic effect. Conjugate.

In a specific embodiment, the present invention provides a conjugate as shown in formula I;

Y1-L1-Z1(I)

Among them, the definitions of Y1, L1 and Z1 are as described in the first aspect.

In another specific embodiment, L1 can also be a linking group selected from the following group:

in,

In another specific preferred example, L1 can also be a linking group selected from the following group:

in,

In another specific embodiment, the conjugate is selected from Table A

Table A

In another specific embodiment, the conjugate is selected from Table B1 and Table B2

Table B1

Table B2

In another specific embodiment, the conjugate is selected from Table C1 and Table C2:

Table C1

Table C2

Preparation

The conjugate or labeled compound of the present invention can be prepared by conventional methods with suitable raw materials, or prepared according to the methods disclosed in the specific examples.

Contrast agent or radiotherapeutic agent

The conjugate (formula I) according to the present invention is used as a radiographic agent or a radiotherapeutic agent (drug) or a diagnostic agent, and different isotopes such as radioisotopes are complexed and chelated to the chelate moiety. Exemplary isotopes include, for example: Tc-99m, Ga-68, F-18, I-123, I-125, I-131, In-111, Ga-67, Cu-64, Zr-89, C- 11. Lu-177, Re-188, Lu-177, Y-90, Ac-225, As-211, Bi-212, Bi-213, Cs-137, Cr-51, Co-60, Dy-165, Er-169, Fm-255, Au-198, Ho-166, I-125, I-131, Ir-192, Fe-59, Pb-212, Mo-99, Pd-103, P-32, K- 42, Re-186, Re-188, Sm-153, Ra223, Ru-106, Na24, Sr89, Tb-149, Th-227, Xe-133Yb-169, Yb-177.

Pharmaceutical composition and method of administration

As used herein, the term "compound of the present invention" or "conjugate of the present invention" refers to a compound or conjugate represented by formula I.

Since the conjugate of the present invention has excellent prostate-specific membrane antigen (PSMA) binding ability, the conjugate or compound or labeled compound of the present invention, pharmaceutically acceptable inorganic or organic salt, hydrate or solvate, and The composition containing the compound of the present invention as the main active ingredient can be used for the treatment, prevention and diagnosis of prostate cancer and related diseases such as its metastasis.

The composition of the present invention contains the compound of the present invention or a pharmacologically acceptable salt thereof and a pharmacologically acceptable excipient or carrier within a safe and effective amount. The "safe and effective amount" refers to: the amount of the compound is sufficient to significantly improve the condition without causing serious side effects. Generally, the pharmaceutical composition contains 1-2000 mg of the compound of the present invention per agent, and more preferably, contains 10-500 mg of the compound of the present invention per agent. Preferably, the "one dose" is a capsule or tablet.

"Pharmaceutically acceptable carrier" refers to: one or more compatible solid or liquid fillers or gel substances, which are suitable for human use, and must have sufficient purity and sufficiently low toxicity. "Compatibility" here means that the components in the composition can be blended with the compound of the present invention and between them without significantly reducing the efficacy of the compound. Examples of pharmaceutically acceptable carriers include cellulose and its derivatives (such as sodium carboxymethyl cellulose, sodium ethyl cellulose, cellulose acetate, etc.), gelatin, talc, and solid lubricants (such as stearic acid). , Magnesium stearate), calcium sulfate, vegetable oils (such as soybean oil, sesame oil, peanut oil, olive oil, etc.), polyols (such as propylene glycol, glycerin, mannitol, sorbitol, etc.), emulsifiers (such as Tween)

), wetting agents (such as sodium lauryl sulfate), coloring agents, flavoring agents, stabilizers, antioxidants, preservatives, pyrogen-free water, etc.

The method of administration of the compound or pharmaceutical composition of the present invention is not particularly limited. Representative administration methods include (but are not limited to): oral, intratumoral, rectal, parenteral (intravenous, intramuscular, or subcutaneous), and topical administration .

Solid dosage forms for oral administration include capsules, tablets, pills, powders and granules. In these solid dosage forms, the active compound is mixed with at least one conventional inert excipient (or carrier), such as sodium citrate or dicalcium phosphate, or mixed with the following ingredients: (a) fillers or compatibilizers, for example, Starch, lactose, sucrose, glucose, mannitol and silicic acid; (b) binders such as hydroxymethyl cellulose, alginate, gelatin, polyvinylpyrrolidone, sucrose and gum arabic; (c) humectants, For example, glycerin; (d) disintegrants, such as agar, calcium carbonate, potato starch or tapioca starch, alginic acid, certain complex silicates, and sodium carbonate; (e) slow solvents, such as paraffin; (f) Absorption accelerators, such as quaternary amine compounds; (g) wetting agents, such as cetyl alcohol and glyceryl monostearate; (h) adsorbents, such as kaolin; and (i) lubricants, such as talc, hard Calcium fatty acid, magnesium stearate, solid polyethylene glycol, sodium lauryl sulfate, or mixtures thereof. In capsules, tablets and pills, the dosage form may also contain buffering agents.

Solid dosage forms such as tablets, sugar pills, capsules, pills and granules can be prepared with coatings and shell materials, such as enteric coatings and other materials known in the art. They may contain opacifying agents, and the active compound or the release of the compound in such a composition may be released in a certain part of the digestive tract in a delayed manner. Examples of embedding components that can be used are polymeric substances and waxes. If necessary, the active compound can also be formed into microcapsules with one or more of the above-mentioned excipients.

Liquid dosage forms for oral administration include pharmaceutically acceptable emulsions, solutions, suspensions, syrups or tinctures. In addition to the active compound, the liquid dosage form may contain inert diluents conventionally used in the art, such as water or other solvents, solubilizers and emulsifiers, for example, ethanol, isopropanol, ethyl carbonate, ethyl acetate, propylene glycol, 1 , 3-Butanediol, dimethylformamide and oils, especially cottonseed oil, peanut oil, corn germ oil, olive oil, castor oil and sesame oil or mixtures of these substances.

In addition to these inert diluents, the composition may also contain adjuvants such as wetting agents, emulsifying and suspending agents, sweetening agents, flavoring agents and perfumes.

In addition to the active compound, the suspension may contain suspending agents, for example, ethoxylated isostearyl alcohol, polyoxyethylene sorbitol and sorbitan esters, microcrystalline cellulose, aluminum methoxide and agar, or mixtures of these substances, and the like.

The composition for parenteral injection may contain physiologically acceptable sterile aqueous or non-aqueous solutions, dispersions, suspensions or emulsions, and sterile powders for reconstitution into sterile injectable solutions or dispersions. Suitable aqueous and non-aqueous carriers, diluents, solvents or excipients include water, ethanol, polyols and suitable mixtures thereof.

The dosage form of the compound of the present invention for topical administration includes ointment, powder, patch, propellant and inhalant. The active ingredient is mixed under sterile conditions with a physiologically acceptable carrier and any preservatives, buffers, or propellants that may be required if necessary.

The compounds of the present invention can be administered alone or in combination with other pharmaceutically acceptable compounds.

When the pharmaceutical composition is used, a safe and effective amount of the compound of the present invention is applied to a mammal (such as a human) in need of treatment. The dosage is usually 1 to 2000 mg, preferably 20 to 500 mg. Of course, the specific dosage should also consider factors such as the route of administration and the patient's health status, which are all within the skill range of a skilled physician.

The main advantages of the present invention include:

a) Different linkers are used to create a new small molecular structure, which reduces the renal radiation dose and toxicity compared with the existing PSMA radioligands of the same type.

b) The chelate uses DOTAGA. Now the commonly used PSMA binding ligand-linker-chelate mainly uses DOTA. DOTAGA can connect radioisotopes more effectively and stably

c) The conjugate of the present invention can be used as a binding albumin binder, thereby effectively enhancing the blood circulation of the PSMA radioligand, positively affecting the overall movement characteristics of the drug, increasing the accumulation of tumor radioactivity, and improving the therapeutic effect.

The present invention will be further explained below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. The experimental methods that do not indicate specific conditions in the following examples usually follow the conventional conditions or the conditions recommended by the manufacturer. Unless otherwise specified, percentages and parts are weight percentages and parts by weight.

Example 1: Synthesis of DOTAGA coupling ligand

PSMA ligand linked to DOTAGA is synthesized by solid-phase peptide synthesis.

Ho in a first step by 3h at will in 5 ℃ bis (t-butyl) 3 mmol of 200ml of dry CH ₂ Cl ₂ in 3ml of -L- glutamate and N- ethyldiisopropylamine (DIPEA) Add 10ml of _{1mmol triphosgene in dry CH 2} Cl ₂ to generate glutamyl moiety isocyanate in situ, and add 0.5mmol resin fixed (2-chloro-trityl resin) E after the reaction -Allyloxycarbonyl-protected lysine was reacted for 16h under gentle stirring, the resin was filtered off and _{50mg tetrakis(triphenyl)palladium in 4ml CH 2} Cl ₂ and 400 μl morpholine were used to remove the alkene in 2h Propoxy protecting group.

The subsequent synthesis of the peptidomimetic PSMA binding motif was carried out according to the standard Fmoc process, using 2mmol of the corresponding Fmoc protected acid in the final volume of 4ml DMF, 3.96nmol of HBTU and 2mmol of N-ethyl-diisopropylamine for connection The connection of the base part was activated with 3.95 eq of HBTU and DIPEA for 1 h, and then 4 eq of DODAGA-NHS relative to the resin load was reacted in a final volume of 3 ml of DMF. The product was cut from the resin in a mixture of 2 ml of trifluoroacetic acid, triisopropylsilane, and water (95:2.5:2.5), and purified by RP-HPLC (reversed-phase high-performance liquid chromatography), thereby The compounds shown in Table A were obtained.

RP-HPLC and ion chromatography were used to determine the purity and TFA (trifluoroacetic acid) content of synthetic compounds (see Figures 1A-1E for the results of RP-HPLC and ion chromatography), and high-resolution mass spectrometry was used to identify the compounds. The quality control data of the compounds are shown in Table 1.

Table 1 Quality control data of the compound

To	Appearance	Molecular weight	purity	TFA content
Compound 1	White powder	1273Da	>99%	12.4%
Compound 2	White powder	1461Da	>98%	10.1%
Compound 3	White powder	1605Da	>97%	8.2%
Compound 4	White powder	1475Da	>98%	9.3%
Compound 5	Yellow powder	1325Da	>97%	0.7%

Example 2: ¹⁷⁷ Lu radioactive labeling and stability test

1nmol of compound 1-5 and PSMA-I&T (purchased from Scintomys GmbH) synthesized in Example 1 were dissolved in 100μl of 0.5M pH8.0 sodium acetate solution, and 10μl of 2M pH8.0 sodium acetate solution and 40μl of ¹⁷⁷ LuCl were added. _{3 In} the mixture of eluent (50MBq), adjust the pH of the labeling solution to 4, react at 95°C for 45 minutes, and use RP-HPLC and thin layer chromatography to ^{perform quality control on the 177} Lu labeled compound to obtain ⁷⁷ Lu labeled compound .

In addition, 30 μl of ¹⁷⁷ Lu labeled compound was added to 300 μl of phosphate buffer or human serum, and incubated at 37° C. for 1, 6 and 24 hours. ^{The stability of 177} Lu labeled compound was analyzed by RP-HPLC and thin layer chromatography. ^{The radiochemical purity and stability data of 177} Lu labeled compounds are shown in Table 2.

The results showed that the ^{radiochemical purity of the 177} Lu labeled compound of the present invention reached more than 95%, and it was very stable without any degradation after 24 hours incubation in the serum.

Table 2 Radiochemical purity and stability data of ^{77 Lu labeled compounds}

Example 3: In vitro PSMA binding test

^{Inoculate 5×10 5} PSMA high-expressing (LNCaP C4.2) cells in the right armpit of Balb/c nude mice ^{. When the tumor grows to 100-200mm 3,} remove the tumor, prepare a 5mm thick frozen section, and attach it On the glass slide. Put the glass slide into the protein solution, incubate at room temperature for 20 minutes for pre-blocking, then transfer to 40ml containing 0.5% bovine serum albumin phosphate buffer, add 0.2nM ¹⁷⁷ Lu labeled compound prepared in Example 2, or add at the same time 0.04, 0.2, 1, 5, and 25 nM of the compound of Example 1 were incubated at room temperature for 1 h, then the slides were washed 4 times with ice-cold buffer for 3 min each, dried at room temperature and attached to the phosphorescent imaging plate and exposed for 15 min. Scan the glass slide with a biological imaging analyzer, and use image analysis software to calculate ^{the affinity of the 177} Lu labeled compound with PSMA. The results show that the ¹⁷⁷ Lu labeled compound of the present invention has an affinity for PSMA above nM and is determined to be a specific binding.

Example 4: SPECT imaging study

^{Inoculate 5×10 5} PSMA highly expressing (LNCaP C4.2) cells in the right armpit of Balb/c nude mice ^{, and wait until the tumor grows to 300-600mm 3} for formal experimental research.

The tumor-bearing mice were anesthetized by isoflurane, and the ¹⁷⁷ Lu labeled compound of Example 2 (~1 nmol, 40 MBq) was injected into the tail vein. Scanning was performed 2, 24, and 72 hours after administration, and the acquisition method was static 30-min SPECT and medium-resolution whole-body CT. After completing the SPECT/CT scan, perform organ dissection, weigh and use a gamma counter to measure radioactivity and calculate ID/g. Formalin fixes the organ and uses it for H&E staining.

According to the obtained 72h SPECT/CT scan pictures and the distribution data in the body, it can be seen that the ¹⁷⁷ Lu labeled compound of the present invention is more effective than PSMA-I&T in enhancing blood circulation in the body and reducing the radiation dose in the kidney, increasing the accumulation and absorption of tumor radioactivity. The overall movement characteristics of the drug have a positive effect.

Example 5: Efficacy study

^{Inoculate 5×10 5} PSMA highly expressing (LNCaP C4.2) cells in the right armpit of Balb/c nude mice ^{, and wait until the tumor grows to 100-200mm 3} for formal experimental research.

^{The 177} Lu labeled compound of Example 2 (~2nmol, 60MBq) was injected into the tail vein. The behavior and survival rate of the mice were monitored daily, and the body weight and tumor growth were monitored twice a week. SPECT/CT scan was performed 72 hours after the administration, and the acquisition method was static 30-min SPECT and medium-resolution whole-body CT. The organs were dissected 8 weeks after the administration, and formalin fixed the organs for H&E staining.

According to the ^{72-hour SPECT/CT scan pictures and tumor growth data of some 177} Lu labeled compounds obtained in tumor-bearing mice, it can be seen that the ¹⁷⁷ Lu labeled compound of the present invention can more effectively inhibit tumor growth and improve survival rate of tumor-bearing mice compared with PSMA-I&T. At the same time, the body weight of the tumor-bearing mice remained unchanged or increased during the survival period, and there were no obvious signs of toxicity.

All documents mentioned in the present invention are cited as references in this application, as if each document was individually cited as a reference. In addition, it should be understood that after reading the above teaching content of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Claims (10)

1. A conjugate, characterized in that the conjugate is as shown in formula I

   Y1-L1-Z1 (I)

   in,

   (i) Y1 is the chelate part;

   (ii) Z1 is the PSMA binding ligand part as shown in formula III;

   

   Wherein, R ^{1 is} each independently selected from the following group: -COOH, -SO ₂ H, -CO ₃ H, -CO ₄ H, -PO ₂ H, -PO ₃ H, and -PO ₄ H ₂ ; and

   (iii) L1 is a linking group for connecting the Z1 and the Y1, and the linking mode of the linking group and the Y1 and the Z1 is covalent connection; and

   L1 consists of two or more structural units selected from the following group:

   

   Amino acid residues, -NR ³ -L2-NR ³ -, -NR ³ -L2-CO-, -CO-L2-NR ³ -, C1-C8 alkylene;

   R is selected from the following group: substituted or unsubstituted -C1-C4 alkylene-C6-C10 aryl, substituted or unsubstituted -C1-C4 alkylene-5 to 10-membered heteroaryl; wherein, the Heteroaryl groups contain 1 to 5 heteroatoms selected from O, S and N; the said substitution means that one or more hydrogens in the group are replaced by a substituent selected from the following group: C1-C4 alkyl , Phenyl, phenyl substituted with one or more C1-C4 alkyl groups;

   L2 is a C1-C8 alkylene group that is unsubstituted or substituted by one or more R ^2;

   R ^{2 is} each independently selected from the following group: C1-C4 alkyl, -COOH, -C(O)N(R ³ ) ₂ , -COO-C1-C4 alkyl; and

   R ^{3 is} selected from the group consisting of H, C1-C4 alkyl.
2. The conjugate according to claim 1, wherein L1 is a linking group as shown in formula IV;

   -(A ¹ ) _n1 -A ^a -(A ² ) _n2 -A ^b -(A ³ ) _n3 -* (IV)

   in,

   * Indicates the end connected to Z1;

   A ^a is

   

   And A ^b is

   

   Or A ^a is

   

   And A ^b is

   

   A ¹ , A ² and A ³ are each independently a structural unit selected from the following group:

   Amino acid residues, -NR ³ -L2-NR ³ -, -NR ³ -L2-CO-, C1-C8 alkylene;

   L2, R and R ^{3 are} as defined above;

   n1, n2, and n3 are each independently an integer from 0 to 20; and n1, n2, and n3 are not 0 at the same time.
3. The conjugate according to claim 1, wherein L1 is a linking group as shown in formula IVb,

   

   Wherein, * represents the end connected to Z1; L ^{3 is} defined as L2; A ⁴ is an amino acid residue or -NR ³ -L2-CO-; and n4 = 0, 1, 2, 3, 4, 5, 6, or 7.
4. The conjugate according to claim 1, wherein Y1 is represented by formula II;

   

   and / or

   Z1 is shown in formula IIIa

   
5. The conjugate according to claim 1, wherein the conjugate is selected from Table A, Table B1, Table B2, Table C1 and Table C2;

   Table A

   

   

   Table B1

   

   Table B2

   

   Table C1

   

   Table C2

   
6. The use of the compound of claim 1 in the preparation of a labeled compound.
7. A labeling compound, characterized in that the labeling compound comprises the conjugate according to claim 1, and a label connected to or combined with or complexed or chelated with the conjugate.
8. A composition, characterized in that the composition comprises the conjugate according to claim 1 or the labeled compound according to claim 7.
9. A use of the conjugate according to claim 1 or the labeled compound according to claim 7 in the preparation of imaging agents and/or radiotherapeutic agents and/or diagnostic agents.
10. A use of the conjugate according to claim 1 or the labeled compound according to claim 7 in the preparation of a medicament for the diagnosis and/or treatment of prostate cancer and/or its metastasis.

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