Sar bicyclic peptide radionuclide ligands targeting nectin-4, probes, methods of making and uses

Abstract

The present application relates to a novel bicyclic peptide targeted radiopharmaceutical ligand and its radionuclide probe, and a preparation method and application thereof. The ligand and probe can be used for imaging diagnosis of Nectin-4 positive tumor patients, and are expected to be used for tumor treatment. In addition, they can provide drug guidance and real-time efficacy monitoring for patients receiving anti-cancer targeted drug treatment. In the present application, by introducing a pharmacokinetic modification segment sarcosine (Sar) between the radionuclide labeled chelator and the Nectin-4 targeting polypeptide, the N-methylation of Sar reduces the recognition and cleavage ability of proteases, and further shields the action site of proteases (such as trypsin, carboxypeptidase, etc.), thereby reducing the degradation of the polypeptide in vivo, and further improving its metabolic stability and the retention time of the molecular probe in vivo. The methylation of Sar increases the overall hydrophobicity of the polypeptide, but at the same time reduces the polarity. The increase in hydrophobicity may improve the ability of the polypeptide to pass through the cell membrane, and increase its efficiency of entering the target cells. The decrease in solubility may lead to a decrease in the solubility of the polypeptide in the aqueous environment, which needs to be solved by formulation optimization. In summary, the present application provides a novel bicyclic peptide targeted radiopharmaceutical ligand and radionuclide probe with innovation and practicality, and provides a new strategy and tool for the diagnosis and treatment of Nectin-4 positive tumors.

Description

Technical Field

[0001] This invention belongs to the field of nuclear medicine technology, specifically relating to a Sar bicyclic peptide nuclide ligand, probe, preparation method, and application of Nectin-4. Background Technology

[0002] Early and accurate detection of lesions throughout the body using nuclear medicine imaging techniques can provide clinicians with better guidance for treatment. Currently, molecular imaging modalities mainly include: molecular magnetic resonance imaging, optical imaging, targeted ultrasound, single-photon emission computed tomography (SPECT), and positron emission tomography (PET). Among these, nuclear medicine imaging (PET, SPECT) plays an increasingly important role in clinical practice due to its high sensitivity, strong tissue penetration, ability to perform in vivo quantification, and availability of multiple radionuclides.

[0003] Nectin-4 (gene name PVRL4, poliovirus receptor 4) protein belongs to the Nectin family of the immunoglobulin superfamily. The Nectin family works in conjunction with cadherins to significantly influence the generation and maintenance of adhesive and tight junctions, regulating various cellular behaviors including cell adhesion, growth, differentiation, migration, and apoptosis. Nectin-4 protein is specifically expressed in the embryo and placenta, expressed in a few normal adult tissues (including skin), and upregulated in certain cancer patients, such as urothelial carcinoma, breast cancer, ovarian cancer, and pancreatic cancer; its overexpression is associated with tumor progression and poor clinical prognosis. Therefore, exploring targeted Nectin-4 protein and combination therapies may provide more treatment options for patients with advanced solid tumors.

[0004] Enfortumab vedotin is an FDA-approved targeted therapy for Nectin-4 positive (urothelial carcinoma) tumors, demonstrating efficacy in both early and advanced (metastatic) tumors. However, while some patients are sensitive to Enfortumab vedotin, others develop varying degrees of resistance after a period of targeted therapy. Due to the long treatment cycle of anti-Nectin-4 targeted therapy, the high cost of antibody drugs, and the tendency to develop resistance, designing novel molecular probes targeting the Nectin-4 site in breast cancer is crucial for screening Nectin-4 positive tumor patients, real-time efficacy monitoring during Enfortumab vedotin treatment, and designing personalized precision medicine. Summary of the Invention

[0005] This invention aims to provide a bicyclic peptide ligand and probe targeting Nectin-4, along with their preparation method and applications. The ligand and probe can specifically and targetedly be used for imaging diagnosis of Nectin-4 positive tumor patients, thus enabling medication guidance and real-time efficacy monitoring for patients receiving targeted anticancer drug therapy. The invention employs the following technical solution:

[0006] A first aspect of the present invention provides a Sar bicyclic peptide ligand targeting Nectin-4, the structure of which is shown in formula (I):

[0007]

[0008] In formula (I): Sar is a pharmacokinetic modified molecule, polysarcosine; L is a metal chelating agent;

[0009] Furthermore, L is selected from any one or more of DOTA, NOTA, HYNIC, TPA, DTPA, NODAGA, TETA, PCTA, and DOTAM; even further, L is DOTA;

[0010] Furthermore, the degree of polymerization of the Sar is 11 to 30, preferably 20;

[0011] A second aspect of the present invention provides a method for preparing any of the above-mentioned Sar bicyclic peptide ligands targeting Nectin-4, comprising the following steps:

[0012] S1: The α-amino group and side chain functional groups of the amino acids in the bicyclic peptide targeting Nectin-4 are protected by a functional group protector, and then the peptide is activated.

[0013] S2: The above-mentioned bicyclic peptide was condensed with the metal chelating agent L in dimethyl sulfoxide or N,N-dimethylformamide by solid-phase synthesis. After deprotection and purification, L-Sar-peptide-resin was prepared.

[0014] S3: In a mixture of triethanolamine (TFA), 1,2-ethylenedithiol (EDT), triisopropylsilane (TIS) and water, the metal chelating agent L-Sar-peptide-resin obtained in step S2 is subjected to a resin cleavage reaction. Then, the cleaved metal chelating agent L-Sar-peptide is reacted in TATA solution to obtain DOTA-Sar-bicyclic peptide ligand.

[0015] Furthermore, in S1, the functional group protecting agent is selected from any one or more of 9-fluoromethyl carbonyl, tert-butyloxycarbonyl (BOC), triphenylmethyl (Trt), and tert-butyl ester (OtBu);

[0016] Furthermore, in S1, the activation is carried out in an activation mixture of dicatalytic carbon tetrachloride (DCC) and diisopropylcarbamate (DIC) with a volume ratio of 0.5 to 2:1.

[0017] Furthermore, in S1, the mass ratio of the bicyclic peptide to the activation mixture is 1:500 to 1000;

[0018] Furthermore, in S2, the molar ratio of the bicyclic peptide to the metal chelating agent L is 1:1;

[0019] Furthermore, in S3, the mixture is prepared in a volume ratio of TFA, 1,2-ethylenedithiol EDT, triisopropylsilane TIS, and water of 80-100:5:2-3:2-3.

[0020] A third aspect of the present invention provides a Sar bicyclic peptide nuclide probe targeting Nectin-4, comprising any of the aforementioned bicyclic peptide nuclide ligands targeting Nectin-4 and a radionuclide.

[0021] Furthermore, the radionuclide is selected from... 99m Tc, 68 Ga、 64 Cu、 111 In、 90 Y、 225 Ac、 137 Cs、 90 Sr、 125 I, 131 I, 153 Sm and 177 Any one or more of Lu;

[0022] Furthermore, the radioactive nuclide is 68 Ga;

[0023] A fourth aspect of the present invention provides a method for preparing any of the above-mentioned Sar bicyclic peptide nuclide probes targeting Nectin-4, comprising the following steps:

[0024] Prepare an aqueous mixture containing ammonium acetate and a Sar bicyclic peptide ligand targeting Nectin-4, add a radioactive nuclide solution, heat the mixture to react, and cool it to room temperature after the reaction is complete to prepare a Nectin-4 bicyclic peptide probe.

[0025] Furthermore, the concentration of the ammonium acetate solution is 1–2 M;

[0026] Furthermore, the concentration of the Sar bicyclic peptide ligand targeting Nectin-4 is 0.5–3 μg / μL.

[0027] Furthermore, in the mixture, the volume ratio of ammonium acetate to the Sar bicyclic peptide ligand targeting Nectin-4 is 3 to 5:1;

[0028] Furthermore, the concentration of the radionuclide solution is 2–5 mCi;

[0029] Furthermore, the volume ratio of the radionuclide solution to the mixed liquid is 6000–10000:1;

[0030] Furthermore, the heating temperature is 70–90°C;

[0031] Furthermore, the reaction time is 15–60 min;

[0032] The fifth aspect of the present invention provides the use of any of the above-mentioned Sar bicyclic peptide ligands or probes targeting Nectin-4 in the preparation of diagnostic agents for Nectin-4 related diseases, targeted drugs for the treatment of Nectin-4 related diseases, or evaluation agents for targeted drugs for Nectin-4 related diseases.

[0033] Furthermore, the Nectin-4 related diseases are selected from any one or more of urothelial carcinoma, breast cancer, pancreatic cancer, bladder cancer, lung cancer, ovarian cancer, and other tumors that can affect Nectin-4 expression changes;

[0034] Furthermore, the targeted drug for Nectin-4 related diseases is veentumumab;

[0035] Beneficial effects

[0036] Compared with the prior art, the beneficial effects of the present invention include at least the following:

[0037] First, the bicyclic peptide nuclide ligand and bicyclic peptide nuclide probe of the present invention can be used for imaging diagnosis of Nectin4 positive tumor patients, which can realize the diagnosis of the disease. Furthermore, it can realize medication guidance and real-time efficacy monitoring for patients receiving anticancer drugs, especially veentumumab treatment.

[0038] Secondly, the bicyclic peptide nuclide ligand DOTA-Sar-bicyclic peptide of the present invention incorporates the pharmacokinetic modification molecule polysarcosine (Sar 20) between the chelating agent used for radionuclide labeling and the Nectin-4-targeted peptide, which improves the biocompatibility of the probe, optimizes the pharmacokinetic properties, and prolongs the in vivo metabolic time, especially the clearance kinetics of non-tumor tissues, so as to achieve better diagnostic and therapeutic effects.

[0039] Third, the bicyclic peptide nuclide ligand DOTA-Sar-bicyclic peptide of the present invention uses a bifunctional chelating agent, which gives it better in vivo and in vitro stability. This characteristic is crucial for improving the efficacy and safety of radiopharmaceuticals. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0041] Figure 1 MS spectrum of DOTA-Sar20-FDSH-4;

[0042] Figure 2 for 68 Radio HPLC analysis chromatogram of Ga-DOTA-Sar20-FDSH-4;

[0043] Figure 3 for 68 In vitro stability analysis diagram of Ga-DOTA-Sar20-FDSH-4;

[0044] Figure 4 For injection 68 PET / CT images of NSG mouse HT1376 bladder cancer model after Ga-DOTA-Sar20-FDSH-40.5h, 1h, 2h and 3h;

[0045] Figure 5 For injection 68 Graphs of %ID / g data from the NSG mouse HT1376 bladder cancer model after Ga-DOTA-Sar20-FDSH-40.5h, 1h, 2h and 3h;

[0046] Figure 6 For injection 68 T / NT data in NSG mouse HT-1376 bladder cancer model after 41h, 2h and 3h of Ga-DOTA-Sar20-FDSH;

[0047] Figure 7 For injection 68 Blood clearance analysis in normal mice after Ga-DOTA-Sar20-FDSH-4; Figure 8 For PET / CT images of the compound of this patent and 68 Ga-N188 image comparison chart Detailed Implementation

[0048] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0049] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0050] Example 1: Preparation of Sar bicyclic peptide ligand targeting Nectin-4

[0051] A method for preparing the bicyclic peptide DOTA-Ala-(Sar)20-Cys-Pro-2-Nal-Asp-Cys-Met-Arg-Asp-Trp-Ser-Thr-Pro-Hyp-Trp-Asn-Cys-NH2(TATACyclized)) ligand includes the following steps:

[0052] (1) Overview of the synthesis steps

[0053] 1) Resin preparation

[0054] RinkAmide MBHAResin was used as the solid support. The resin was swollen with DMF (dimethylformamide), typically soaked for 30 minutes to ensure full swelling.

[0055] 2) Amino acid coupling

[0056] Starting from the C-terminus, amino acids are coupled to the resin step by step. Before each coupling, the Fmoc protecting group is removed with a 20% piperidine / DMF solution to expose the amino group of the amino acid. HATU (O-(7-azabenzotriazol-1-yl)-1,1,3,3-tetramethylurea hexafluorophosphate) is used as the coupling agent, and DIEA (N,N-diisopropylethylamine) is used as the base to couple the next amino acid to the resin. After each coupling, the resin is washed with DMF to ensure complete reaction.

[0057] 3) Treatment of protecting groups

[0058] During synthesis, some amino acids have side-chain protecting groups (such as Trt, Boc, Pbf, OtBu, etc.). These protecting groups remain stable during synthesis until the final deprotection step.

[0059] 4) Stepwise synthesis: Amino acids are coupled sequentially from the C-terminus to the N-terminus of the polypeptide sequence. Below are examples of some steps:

[0060] Cys(Trt): After removing Fmoc protection, Fmoc-Cys(Trt)-OH is coupled to the resin.

[0061] Met: After removing Fmoc protection, Fmoc-Met-OH is coupled.

[0062] Arg(Pbf): After removing Fmoc protection, Fmoc-Arg(Pbf)-OH is coupled.

[0063] Asp(OtBu): After removing Fmoc protection, Fmoc-Asp(OtBu)-OH is coupled.

[0064] Trp(Boc): After removing Fmoc protection, Fmoc-Trp(Boc)-OH is coupled.

[0065] Ser(tBu): After removing Fmoc protection, Fmoc-Ser(tBu)-OH is coupled.

[0066] Thr(tBu): After removing Fmoc protection, Fmoc-Thr(tBu)-OH is coupled.

[0067] Pro: After removing Fmoc protection, Fmoc-Pro-OH is coupled.

[0068] Hyp(tBu): After removing Fmoc protection, Fmoc-Hyp(tBu)-OH is coupled.

[0069] Trp(Boc): After removing Fmoc protection, Fmoc-Trp(Boc)-OH is coupled.

[0070] Asn(Trt): After removing Fmoc protection, Fmoc-Asn(Trt)-OH is coupled.

[0071] Cys(Trt): After removing Fmoc protection, Fmoc-Cys(Trt)-OH is coupled.

[0072] RinkAmide MBHAResin: This process ultimately cleaves the peptide from the resin.

[0073] 5) Ultimately, to protect

[0074] After synthesis, final deprotection is performed using a TFA (trifluoroacetic acid) mixture (typically containing TFA, water, and TIS = 92:3:5), simultaneously cleaving the peptide from the resin. Following deprotection, the peptide is purified by precipitation and centrifugation: (DOTA(tBu)3-β-Ala-(Sar)20-Cys(Trt)-Pro-2-Nal-Asp(OtBu)-Cys(Trt)-Met-Arg(Pbf)-Asp(OtBu)-Trp(Boc)-Ser(tBu)-Thr(tBu)-Pro-Hyp(tBu)-Trp(Boc)-Asn(Trt)-Cys(Trt)-RinkAmide MBHAResin)

[0075] 6) Purification and Characterization

[0076] The peptide was purified using HPLC (High Performance Liquid Chromatography); its structure and purity were confirmed by mass spectrometry (MS) and nuclear magnetic resonance (NMR): (DOTA-β-Ala-(Sar)20-Cys-Pro-2-Nal-Asp-Cys-Met-Arg-Asp-Trp-Ser-Thr-Pro-Hyp-Trp-Asn-Cys-NH2)(TATACyclized)). It is denoted as DOTA-Sar-peptide.

[0077] (2) The DOTA-Sar-peptide obtained in step (1) is reacted via a three-step Michael addition of cysteine ​​residues in the DOTA-Sar-peptide to 1,1',1”-(1,3,5-triazine-1,3,5-triyl)triprop-2-en-1-one (TATA) (mass-volume ratio of DOTA-Sar-peptide to TATA is 1 mg: 1 mL) under alkaline conditions to obtain the cyclic product DOTA-Sar-bicyclic peptide ligand.

[0078] The synthesis route diagram is as follows:

[0079]

[0080] MS spectrum analysis of DOTA-Sar-FDSH-4 can be found in [link to analysis]. Figure 1 .

[0081] Example 2: Preparation of a bicyclic peptide nuclide probe targeting Nectin-4

[0082] 68 Preparation of Ga-DOTA-Sar20-FDSH-4:

[0083] Take 44 μL of 1.5 M ammonium acetate solution and slowly add it to a solution containing 10 μL of the 1 μg / μL bicyclic peptide ligand DOTA-Sar20-FDSH-4. Then add 400 μL (3 mCi concentration) of freshly rinsed radionuclide solution. 68 GaCl3 was heated at 75°C for 20 minutes, and after the reaction was completed, it was cooled to room temperature to prepare a bicyclic peptide nuclide probe targeting Nectin-4. 68 The specific reaction route for Ga-DOTA-Sar20-FDSH-4 is shown below:

[0084]

[0085] right 68 Radioactive HPLC analysis was performed using Ga-DOTA-Sar20-FDSH-4: An Agilent 1260 HPLC system equipped with a YMC-Pack ODS-A analytical column (250 × 4.6 mm L.DS-5 μm, 12 nm) was used. The gradient elution time was 20 min, and the flow rate was 1 mL / min. Mobile phase A was deionized water (containing 0.1% TFA), and mobile phase B was acetonitrile (containing 0.1% TFA). The elution gradient was set to 75% A and 25% B initially, and then 25% A and 75% B after 20 min. The results are as follows: Figure 2 As shown. From Figure 2 It can be seen that, 68 The labeling efficiency of Ga-DOTA-Sar20-FDSH-4 was >95%, and the radiochemical purity after purification by Sep-Pak C18 column was >98%.

[0086] Example 3: In vitro stability experiment of the bicyclic peptide nuclide probe targeting Nectin-4

[0087] Take a certain amount 68 Ga-DOTA-Sar20-FDSH-4 was added to physiological saline, and its radiochemical purity and stability were measured at different time points. The results are shown in [Figure 1]. Figure 3 As shown, after 1 hour, 2 hours, and 3 hours 68 The radiochemical purity of Ga-DOTA-Sar20-FDSH-4 remains greater than 98%, maintaining good stability.

[0088] Example 4: PET Imaging Study

[0089] SPF-grade NSG female mice, 5 weeks old, were provided by Shanghai Yaokang Biotechnology Co., Ltd. After two days of acclimatization in the animal facility, HT1376 human bladder cancer cells were injected subcutaneously into the right axilla of the mice. The injection volume was 0.1 mL (5 × 10⁻⁶). 6(cells / mL dispersed in HBSS), and continued feeding for 2-3 weeks after injection until the solid tumor mass grows to 500-800 mm. 3 It is used for imaging experiments. 100-150 μCi / 0.2 mL is injected via the tail vein. 68 Ga-DOTA-Sar20-FDSH-4 was used in small animal PET imaging experiments at 0.5h, 1h, 2h, and 3h post-injection. The imaging results are as follows: Figure 4 As shown. The results showed that Nectin-4 positive HT1376 tumors... 68 The Ga-DOTA-Sar20-FDSH-4 compound exhibits high uptake, clearly visible tumor uptake, and no gallbladder uptake. The peptide remains at the tumor site for a longer period, which is more conducive to tumor diagnosis.

[0090] Further quantitative results in the HT1376 human bladder cancer tumor model showed that injection 68 Ga-DOTA-Sar20-FDSH-4 uptake in HT1376 human bladder cancer tumors at 30, 60, 120, and 180 minutes. 68 The ID% / g values ​​of Ga-DOTA-Sar20-FDSH-4 were 4±0.4, 4±0.46, 4.1±0.32, and 5.2±0.46, respectively. Figure 5 In the HT1376 human bladder cancer tumor model, tumor uptake... 68 The T / NT values ​​of Ga-DOTA-Sar20-FDSH-4 were 1.63±0.11, 1.58±0.11, 2.09±0.30, and 2.01±0.55, respectively. Figure 6 ).

[0091] Example 5 68 Pharmacokinetic analysis of Ga-DOTA-Sar20-FDSH-4 in normal mice

[0092] Normal mice were randomly divided into several groups, with 3 mice in each group. Each group of mice was injected via the tail vein. 68 Ga-DOTA-Sar20-FDSH-4 was administered to animals at 1 min, 3 min, 5 min, 10 min, 15 min, 30 min, 60 min, 120 min, and 180 min post-injection. Blood samples were collected, weighed, and radioactivity counts were measured. After decay correction, the percentage of injected dose per gram of blood (%ID / g) was calculated. The results showed that... 68 The half-life of Ga-DOTA-Sar20-FDSH-4 in blood clearance is approximately 24 minutes. Figure 7 ).

[0093] Literature reports that 68Ga-N188, when injected into a Nectin-4 positive tumor model... 68 One hour after administration of Ga-DOTA-Sar20-FDSH-4, tumor uptake was below 0.8% ID / g, significantly lower than that of the compound in this patent (Duan X, Xia L, Zhang Z, et al. First-in-human study of the radioligand 68Ga-N188 targeting Nectin-4 for PET / CT imaging of advanced urothelial carcinoma. Clin Cancer Res. 2023; 29:3395–3407.). This result indicates that the PET / CT images of the compound in this patent are superior to those of the compound in this patent. 68 Ga-N188 ( Figure 8 Therefore, compared to 68Ga-N188, this patented compound has greater clinical application value in tumor diagnosis.

[0094] The above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made based on the essence of the content of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A Sar bicyclic peptide ligand targeting Nectin-4, characterized in that, Its structure is shown in equation (I): In formula (I): Sar is a pharmacokinetic modified molecule, polysarcosine; L is a metal chelating agent.

2. The Sar bicyclic peptide ligand targeting Nectin-4 according to claim 1, characterized in that, The L is selected from any one or more of DOTA, NOTA, HYNIC, TPA, DTPA, NODAGA, TETA, PCTA, and DOTAM; furthermore, the L is DOTA.

3. The Sar bicyclic peptide ligand targeting Nectin-4 according to claim 1, characterized in that, The degree of polymerization of the Sar is 11 to 30, preferably 20.

4. A method for preparing the Sar bicyclic peptide ligand targeting Nectin-4 as described in any one of claims 1 to 3, characterized in that, Includes the following steps: S1: The α-amino group and side chain functional groups of the amino acids in the bicyclic peptide targeting Nectin-4 are protected by a functional group protector, and then the peptide is activated. S2: The above-mentioned bicyclic peptide was condensed with the metal chelating agent L in dimethyl sulfoxide or N,N-dimethylformamide by solid-phase synthesis. After deprotection and purification, L-Sar-peptide-resin was prepared. S3: In a mixture of triethanolamine (TFA), 1,2-ethylenedithiol (EDT), triisopropylsilane (TIS) and water, the metal chelating agent L-Sar-peptide-resin obtained in step S2 is subjected to a resin cleavage reaction. Then, the cleaved metal chelating agent L-Sar-peptide is reacted in TATA solution to obtain DOTA-Sar-bicyclic peptide ligand.

5. The method for preparing the Sar bicyclic peptide ligand targeting Nectin-4 according to claim 4, characterized in that, In S1, the functional group protecting agent is selected from any one or more of 9-fluoromethyl carbonyl, tert-butyloxycarbonyl (BOC), triphenylmethyl (Trt), and tert-butyl ester (OtBu).

6. The method for preparing the Sar bicyclic peptide ligand targeting Nectin-4 according to claim 4, characterized in that, In S1, the activation is carried out in an activation mixture of dicatalytic carbon tetrachloride (DCC) and diisopropylcarbamate (DIC) in a volume ratio of 0.5 to 2:

1.

7. The method for preparing the Sar bicyclic peptide ligand targeting Nectin-4 according to claim 4, characterized in that, In S1, the mass ratio of the bicyclic peptide to the activation mixture is 1:500-1000.

8. The method for preparing the Sar bicyclic peptide ligand targeting Nectin-4 according to claim 4, characterized in that, In S2, the molar ratio of the bicyclic peptide to the metal chelating agent L is 1:

1.

9. The method for preparing the Sar bicyclic peptide ligand targeting Nectin-4 according to claim 4, characterized in that, In S3, the mixture is prepared in a volume ratio of TFA, 1,2-ethylenedithiol EDT, triisopropylsilane TIS, and water of 80-100:5:2-3:2-3.

10. A Sar bicyclic peptide nuclide probe targeting Nectin-4, characterized in that, This includes any of the aforementioned bicyclic peptide nuclide ligands and radionuclides that target Nectin-4.

11. The Sar bicyclic peptide nuclide probe targeting Nectin-4 according to claim 11, characterized in that, The radionuclides are selected from 99m Tc, 68 Ga、 64 Cu、 111 In、 90 Y、 225 Ac、 137 Cs、 90 Sr、 125 I, 131 I, 153 Sm and 177 Any one or more of Lu; further, the radionuclide is 68 Ga.

12. A method for preparing a Sar bicyclic peptide nuclide probe targeting Nectin-4, comprising the following steps: Prepare an aqueous mixture containing ammonium acetate and a Sar bicyclic peptide ligand targeting Nectin-4, add a radioactive nuclide solution, heat the mixture to react, and cool it to room temperature after the reaction is complete to prepare a Nectin-4 bicyclic peptide probe. Furthermore, the concentration of the ammonium acetate solution is 1–2 M; Furthermore, the concentration of the Sar bicyclic peptide ligand targeting Nectin-4 is 0.5–3 μg / μL. Furthermore, in the mixture, the volume ratio of ammonium acetate to the Sar bicyclic peptide ligand targeting Nectin-4 is 3 to 5:1; Furthermore, the concentration of the radionuclide solution is 2–5 mCi; Furthermore, the volume ratio of the radionuclide solution to the mixed liquid is 6000–10000:1; Furthermore, the heating temperature is 70–90°C; Furthermore, the reaction time is 15–60 min.

13. The application of a Sar bicyclic peptide ligand or a Sar bicyclic peptide probe targeting Nectin-4 in the preparation of diagnostic agents for Nectin-4-related diseases, targeted drugs for the treatment of Nectin-4-related diseases, or evaluation agents for targeted drugs for Nectin-4-related diseases; Furthermore, the Nectin-4 related diseases are selected from any one or more of urothelial carcinoma, breast cancer, pancreatic cancer, bladder cancer, lung cancer, ovarian cancer, pancreatic cancer, and other tumors that can affect Nectin-4 expression changes; Furthermore, the targeted drug for Nectin-4 related diseases is veentumuzumab.

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