68Ga-labeled CDK19-targeted tumor imaging agent, precursor and application of 68Ga-labeled CDK19-targeted tumor imaging agent and precursor

Abstract

The invention discloses a < 68 > Ga labeled tumor imaging agent for targeting cyclin dependent kinase 19 (CDK19). The imaging agent < 68 > Ga-IRM-8a-8c is prepared from a precursor IRM-8a-8c and a radionuclide < 68 > Ga. The < 68 > Ga-IRM-8a-8c has good in-vitro stability, high affinity and specificity to CDK19 and obvious imaging effect in a mouse prostate cancer model, and PET / CT imaging of a prostate cancer patient proves that the imaging agent < 68 > Ga-IRM-8a-8c can be used as a potential tool for monitoring the expression level of CDK19 in vivo and discussing and clinically diagnosing a prostate cancer mechanism. # imgabs0 #

Description

Technical Field

[0001] The present invention belongs to the technical field of radiopharmaceutical chemistry and relates to a 68 Ga-labeled tumor imaging agent targeting cyclin-dependent kinase 19 (CDK19) and its application. Background Art

[0002] The following background information related to the present invention is provided to help understanding the present invention, but should not be considered as prior art to the present invention. All cited publications are incorporated herein by reference in their entirety.

[0003] Radiopharmaceuticals, which combine radioisotopes with targeted molecules to enable precise imaging and therapy, have become revolutionary tools for the diagnosis and treatment of major diseases, particularly cancer. In recent years, significant progress has been made in the development of radiopharmaceuticals targeting somatostatin receptor 2 (SSTR2), prostate-specific membrane antigen (PSMA), and fibroblast activation protein (FAP), demonstrating their potential as therapeutic diagnostics. These advances are crucial for the transition of nuclear medicine from traditional diagnostics to comprehensive theranostics. However, the current repertoire of molecular targets remains relatively limited, and an incomplete understanding of complex disease mechanisms hinders the wider application of radiopharmaceuticals. Looking ahead, the exploration of new molecular targets will not only improve the specificity and efficacy of these drugs, but also enable the integration of innovative molecular probes and radiolabeling technologies, which are crucial for advancing the development of radiopharmaceuticals. These efforts are expected to expand the therapeutic prospects of radiopharmaceuticals and promote the next generation of precision medicine.

[0004] Recent reports indicate that cyclin-dependent kinase 19 (CDK19) is specifically expressed in prostate cells and overexpressed in prostate cancer (PCa) cells, suggesting it as a promising new nuclear target for prostate cancer imaging and treatment. Recently, we reported the first PET imaging agent 68 Ga-DOTA-IRM-015, which targets CDK19, has high specificity for PCa cells. The study concluded that 68 Ga-CDK19 PET / CT is a potentially effective strategy for detecting lesions regardless of PSMA expression. As one of the few known imaging tracers that targets the cell nucleus, this agent inspired further investigations into structural optimization. A linker optimization strategy was then used to improve pharmacokinetics and enhance tumor uptake of the radioligand. Subsequently, we analyzed the correlation between linker optimization, physicochemical property adjustments, and improved in vivo distribution. Although we found that the compound 68Ga-10c demonstrates imaging potential within 5 minutes to 3 hours after injection and shows promise in alleviating metabolic stress while enhancing tissue safety, but we believe further structural optimization is required before it can be developed into a fully successful imaging agent for use in prostate cancer patients.

[0005] Spirocyclic scaffolds are becoming increasingly important in drug development. These structures are characterized by two or more rings connected by a common atom, forming a rigid three-dimensional framework. Over the past few decades, spirocyclic scaffolds have been successfully incorporated into a variety of approved drugs and drug candidates for the treatment of various diseases, including infections, neurological diseases, metabolic diseases, and cancer. The introduction of spirocyclic rings into lead compounds can enhance specific interactions with protein binding sites, improve potency and selectivity, and positively influence physicochemical properties and pharmacokinetic (PK) characteristics. The development of the marketed drugs togliflozin (a competitive SGLT inhibitor approved in Japan in 2014) and rolapitant (an NK-1 receptor antagonist approved in the United States in 2015) are typical examples of the use of spirocyclic structures. In addition, replacing the central scaffold with a spirocyclic ring can often generate new intellectual property, paving the way for the development of innovative lead structures.

[0006] Therefore, the present invention continues to report the compound 68 Ga-10c was used to design the linker cyclization to obtain three labeled precursor compounds IRM-8a-8c and three 68 Ga-labeled CDK19-targeted imaging agent 68 As expected, a series of in vitro and in vivo experiments showed that 68 Ga-IRM-8c is a promising new PET imaging agent targeting CDK19, with potential for further exploration in clinical diagnostic applications. Subsequently, we performed the first in vivo imaging of a CDK19-targeting ligand in prostate cancer patients. Lesions were accurately detected, and the ligand demonstrated a favorable in vivo safety profile.

[0007] CDK19: targeting cyclin-dependent kinase 19.

[0008] Intermediates are some chemical raw materials or chemical products used in the pharmaceutical synthesis process.

[0009] Prodrugs, also known as precursors, prodrugs, drug precursors, and prodrugs, refer to compounds that are obtained after chemical structure modification of drugs and are inactive or have low activity in vitro, but release active drugs through enzymatic or non-enzymatic conversion in the body to exert their efficacy.

[0010] Labeled prodrugs, also known as labeled precursors, refer to intermediates prepared for the synthesis of the target compound of the present invention or its pharmaceutically acceptable salts. These intermediates typically contain a chemical structure capable of chelating metal nuclides, exhibiting a certain degree of stability and long-term storage. Summary of the Invention

[0011] The present invention aims to provide a method to solve the problems of existing prostate diagnosis and treatment technology. 68 Ga-labeled tumor imaging agent targeting cyclin-dependent kinase 19 (CDK19);

[0012] Another technical problem to be solved by the present invention is to provide the use of the compound in the fields of diagnosis, staging and treatment of prostate cancer.

[0013] A sort of 68 A Ga-labeled tumor imaging agent targeting cyclin-dependent kinase 19 (CDK19), wherein the tumor imaging agent is 68 Ga-IRM-8a-8c, its structural formula is as follows:

[0014]

[0015] At the same time, the present invention provides the use of the above-mentioned compound or a pharmaceutically acceptable salt thereof, and the above-mentioned pharmaceutical composition in the preparation of radionuclide diagnostic and therapeutic reagents targeting CDK19.

[0016] At the same time, the present invention provides the use of the above-mentioned compound or its pharmaceutically acceptable salt, and the above-mentioned pharmaceutical composition in the diagnosis, staging and treatment of CDK19-overexpressing cancers (including but not limited to prostate cancer).

[0017] Furthermore, the tumor imaging agent 68 Ga-IRM-8a-8c is composed of prodrug and radionuclide 68 Ga prepared.

[0018] At the same time, the present invention provides prodrugs (or labeled prodrugs) of the above compounds, IRM-8a-8c, whose structural formula is as follows:

[0019]

[0020] At the same time, the present invention provides the above-mentioned tumor imaging agent 68 The preparation methods of Ga-IRM-8a-8c and prodrug IRM-8a-8c are as follows:

[0021]

[0022] The definitions of substituents R1, R2, and X are as shown in parts a, b, and c of the above figure, respectively.

[0023] The specific steps include:

[0024] 1) 2-Chloroacetyl chloride (1) is coupled with a linker compound (2a-2c) in DCM at room temperature using triethylamine as a base to obtain intermediate compounds 3a-3c in high yield;

[0025] 2) Compounds 3a-3c and compound 4 were coupled at room temperature in the presence of potassium carbonate and acetonitrile to give compounds 5a-5c;

[0026] 3) Removal of BOC protection under TFA and DCM conditions to give compounds 6a-6c;

[0027] 4) Compound 6a-6c obtained in step 3) and tri-tert-butyl 1,4,7,10-tetraazacyclododecane

[0028] -1,4,7,10-tetraacetic acid undergoes an acid ammonium condensation reaction under HATU and DIPEA conditions to obtain compound 7a

[0029] -7c;

[0030] 5) Compounds 7a-7c obtained in step 4) are hydrolyzed under acidic conditions to obtain labeled precursor compounds

[0031] IRM-8a-8c;

[0032] 6) The labeled precursor compound IRM-8a-8c obtained in step 5) is mixed with water. 68 GaCl3 complexation can produce radiolabeled compounds 68 Ga-IRM-8a-8c. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 :PET / CT imaging of tumor-bearing mice (P-16 xenograft tumor): (A) 68 PET / CT imaging and SUVmean value of Ga-IRM-8a; (B) 68 PET / CT imaging and SUVmean value of Ga-IRM-8b; (C) 68 PET / CT imaging and SUVmean values of Ga-IRM-8c. Mice were injected with 3.7±0.4MBq of Ga-IRM-8c via the tail vein. 68 Ga-IRM-8a-8c. Tumors are marked with red dashed lines.

[0034] Figure 2 : SUV ratio study diagram of tumor and non-tumor tissues.

[0035] Figure 3 : Blocking imaging experiment (A) and tissue distribution experiment (B).

[0036] Figure 4 : Patient 1 (AB) and Patient 2 (CE) presented with pelvic lesions after radical prostatectomy and androgen deprivation therapy. 68 Ga-IRM-8c PET / CT imaging: (A) 68 Maximum intensity projection image of Ga-IRM-8c. (B) 68 CT and fusion images of Ga-IRM-8c. (C) 68 Maximum intensity projection image of Ga-IRM-8c. (D) 68 CT and fusion images of Ga-IRM-8c. (E) Immunohistochemical staining analysis of prostate cancer tissue. The tumor location is marked with a red circle.

[0037] Figure 5 :Prostate cancer patients 3 68 Ga-IRM-8c PET / CT imaging with multiple bone metastases. (A) Maximum intensity projection image. (B-C) CT and fusion images. (D) Immunohistochemical staining analysis of prostate cancer tissue. Tumor locations are marked with red circles.

[0038] Figure 6 :Prostate cancer patients with multiple bone metastases 3 68 Ga-PSMA-11 PET / CT imaging. (A) Maximum intensity projection image. (B-C) CT and fusion images. (D) Enhanced CT scan of the prostate. The tumor location is marked with a red circle.

[0039] Figure 7 : Comparison of the average SUVmean values of patient tissue distribution. DETAILED DESCRIPTION

[0040] The compounds and their preparation in the present invention can be better illustrated by the following examples. These examples should not be interpreted as limitations of the present invention, and variations of these compounds known now or developed in the future should also be considered to fall within the scope of the present invention and be protected.

[0041] The following will describe the specific embodiments of the present invention in detail. In order to avoid too many unnecessary details, well-known structures or functions will not be described in detail in the following embodiments.

[0042] Approximate language, as used in the following examples, can be used in quantitative statements to indicate that a certain amount of variation is permissible without changing the basic function. Therefore, the numerical value modified by language such as "approximately" or "approximately" is not limited to the exact numerical value itself. In some embodiments, "approximately" indicates that the modified numerical value can vary within a range of plus or minus ten percent (±10%). For example, "approximately 100" indicates that the value can be anywhere between 90 and 110. Furthermore, in the expression "approximately a first value to a second value," the approximate value modifies both the first and second values. In some cases, approximate language may be related to the accuracy of the measuring instrument.

[0043] Unless otherwise defined, technical and scientific terms used in the following examples have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0044] Example 1 tert-Butyl 4-(2-(2-chloroacetamido)ethyl)piperidine-1-carboxylate (3a)

[0045]

[0046] To a 50 mL dry reaction flask, tert-butyl 4-(2-aminoethyl)piperidine-1-carboxylate (Compound 2a) (5 mmol, 1 eq), TEA (5.25 mmol, 1.05 eq), and DCM (15 mL) were added sequentially. The mixture was cooled to 0°C, and a solution of chloroacetyl chloride (Compound 1) (5 mmol, 1 eq) in DCM (10 mL) was slowly added dropwise. After the addition was complete, the reaction system was stirred at room temperature for 3 hours. After completion of the reaction, the mixture was diluted with water and extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous Na2SO4, and concentrated to yield crude product 3a.

[0047] Example 2 tert-Butyl 4-(2-(2-(4-(4-(isoquinolin-4-yl)phenyl)-1H-pyrazol-1-yl)acetylamino)ethyl)piperidine-1-carboxylate (5a)

[0048]

[0049] 4-(4-(1H-pyrazol-4-yl)phenyl)isoquinoline (Compound 4) (1.73 mmol, 1.0 eq) and Compound 3a (2.08 mmol, 1.2 eq) were dissolved in ACN (15 mL) and KCO (3.63 mmol, 2.1 eq) was added. The mixture was heated at 85°C for 16 hours. The reaction was monitored by thin-layer chromatography. The reaction mixture was extracted with ethyl acetate and water, and the organic phase was washed with brine and dried over anhydrous NaSO. Filtration and concentration gave the crude product, which was then purified by column chromatography to yield the desired compound. 1H NMR (300MHz, DMSO) δ9.34 (s, 1H), 8.47 (s, 1H), 8.23 (d, J = 10.3Hz, 2H), 8.13 (t, J =5.4Hz,1H),8.00(s,1H),7.92(d,J=8.3Hz,1H),7.84-7.71(m,4H),7.55(d,J=8. 2Hz,2H),4.82(s,2H),3.91(d,J=12.2Hz,2H),3.15(dd,J=11.9,5.9Hz,2H),2.76 -2.57(m,2H),1.45-1.32(m,13H),1.06-0.88(m,3H).ESI-MSm / z=540.2985[M+H] + .

[0050] Example 3 2-(4-(4-(Isoquinolin-4-yl)phenyl)-1H-pyrazol-1-yl)-N-(2-(piperidin-4-yl)ethyl)acetamide (6a)

[0051]

[0052] 4.0 mL of a TFA / DCM mixed solution (TFA:DCM=1:3) was added to compound 5a (1.42 mmol), and the mixture was stirred at room temperature for 6 hours. After the reaction, the solvent was evaporated and the pH of the reaction solution was adjusted to 9-10 with sodium hydroxide solution. The crude product was concentrated and purified by column chromatography to obtain the target compound 6a. 1 H NMR (300MHz, DMSO) δ9.34 (s, 1H), 8.47 (s, 1H), 8.28-8.17 (m, 3H), 7.99 (d, J = 5.3Hz, 1H ),7.92(d,J=8.5Hz,1H),7.85-7.70(m,4H),7.55(d,J=8.3Hz,2H),4.83(s,2H),4.12- 4.10(m,2H),3.31-3.23(m,2H),2.82(dd,J=18.5,10.3Hz,2H),1.81(d,J=11.4Hz,2H) ,1.63-1.50(m,1H),1.46-1.35(m,2H),1.35-1.20(m,3H).ESI-MSm / z=440.2458[M+H] + .

[0053] Example 4 2-(4-(4-(Isoquinolin-4-yl)phenyl)-1H-pyrazol-1-yl)-1-(piperazin-1-yl)ethan-1-one (7a)

[0054]

[0055] A mixture of compound 6a (0.46 mmol, 1 eq), DOTA-Ester (0.46 mmol, 1 eq), and HATU (0.46 mmol, 1 eq) was dissolved in DMF (5 mL), followed by the addition of DIPEA (0.92 mmol, 2 eq), and the mixture was heated at room temperature for 3 hours. The reaction was monitored by TLC. The reactants were extracted with ethyl acetate and water, and the organic phase was washed with brine and dried over anhydrous Na2SO4. After filtration and concentration, the crude product was obtained and purified by column chromatography to yield the target compound 7a. ESI-MS m / z = 994.6122 [M+H] + ;1016.5941[M+Na] + .

[0056] Example 5 Tri-tert-butyl 2,2′,2″-(10-(4-(2-(4-(4-(isoquinolin-4-yl)phenyl)-1H-pyrazol-1-yl)acetyl)piperazin-1-yl)-2-oxoethyl)-1,4,7,10-tetraazacyclododecane-1,4,7-triyl)triacetate (IRM-8a)

[0057]

[0058] A TFA / DCM mixture (TFA:DCM = 2:1) was added to 7a (0.36 mmol) and stirred at room temperature for 24 h. After the reaction, the solvent was evaporated and a small amount of methanol was added to dissolve the reaction solution. A 10-fold amount of methyl tert-butyl ether was then added to precipitate the product. The filter cake was collected by filtration to obtain pure IRM-8a. ESI-MS m / z = 826.4256 [M+H] + .

[0059] Example 6 tert-Butyl 7-(2-chloroacetyl)-2,7-diazaspiro[4.4]nonane-2-carboxylate (3b)

[0060]

[0061] To a solution of tert-butyl 2,7-diazaspiro[4.4]nonane-2-carboxylate (compound 2b) (4.29 mmol, 1.0 eq) and TEA (5.15 mmol, 1.2 eq) in DCM (15 mL) was added 2-chloroacetyl chloride (compound 1) (5.15 mmol, 1.2 eq) at 0°C. The mixture was stirred at room temperature for 6 hours. The reaction was monitored by TLC. The reactant was extracted with ethyl acetate and water, and the organic phase was washed with brine and dried over anhydrous Na2SO4. After filtration and concentration, the crude product was obtained, which was purified by column chromatography to obtain compound 3b. 1HNMR(300MHz,DMSO)δ4.29(d,J=9.9Hz,2H),3.55(t,J=7.1Hz,1H),3.44-3.36(m,2H),3.32-3.23 (m,3H),3.19(dd,J=10.9,4.8Hz,2H),1.93-1.73(m,4H),1.39(s,9H).ESI-MSm / z=303.1480[M+H] + ;325.1306[M+Na] + .

[0062] Example 7 tert-Butyl 4-(2-(2-(4-(4-(isoquinolin-4-yl)phenyl)-1H-pyrazol-1-yl)acetylamino)ethyl)piperidine-1-carboxylate (5b)

[0063]

[0064] By referring to the preparation and purification methods of compound 5a in Example 2, the intermediate compound 5b in this example can be obtained. 1 HNMR(300MHz,DMSO)δ9.35(s,1H),8.48(s,1H),8.24(d,J=9.2Hz,2H),8.00(s,1H),7.94(d,J=8.3Hz,1H),7.86-7.72(m,4H),7.56(d,J=7.7Hz,2H ),5.10(d,J=9.4Hz,2H),3.66(t,J=6.7Hz,1H),3.49-3.36(m,3H),3.32- 3.14(m,4H),1.94-1.76(m,4H),1.42(s,9H).ESI-MSm / z=538.2822[M+H] + ;560.2640[M+Na] + .

[0065] Example 8 2-(4-(4-(Isoquinolin-4-yl)phenyl)-1H-pyrazol-1-yl)-1-(2,7-diazaspiro[4.4]nonan-2-yl)ethan-1-one (6b)

[0066]

[0067] By referring to the preparation and purification method of compound 6a in Example 3, the intermediate compound in this example can be obtained. 1HNMR(400MHz,DMSO)δ9.35(s,1H),9.28(s,1H),8.47(s,1H),8.26-8.19(m, 2H),8.01(s,1H),7.93(d,J=8.5Hz,1H),7.84-7.72(m,4H),7.55(d,J=8.3H z,2H),5.14-5.00(m,2H),3.65(t,J=7.0Hz,1H),3.62-3.54(m,1H),3.48-3 .43(m,1H),3.43-3.36(m,4H),3.32-3.26(m,1H),2.10-1.84(m,4H).ESI-MS m / z=438.2309[M+H] + ;460.2125[M+Na] + .

[0068] Example 9 Tri-tert-butyl 2,2',2"-(10-(2-(7-(2-(4-(4-(isoquinolin-4-yl)phenyl)-1H-pyrazol-1-yl)acetyl)-2,7-diazaspiro[4.4]nonan-2-yl)-2-oxoethyl)-1,4,7,10-tetraazacyclododecane-1,4,7-triyl)triacetate (7b)

[0069]

[0070] The intermediate compound of this example was obtained by referring to the preparation and purification method of compound 7a in Example 4. ESI-MS m / z = 992.5971 [M+H] +.

[0071] Example 102, 2',2"-(10-(2-(7-(2-(4-(4-(isoquinolin-4-yl)phenyl)-1H-pyrazol-1-yl)acetyl)-2,7-diazaspiro[4.4]nonan-2-yl)-2-oxoethyl)-1,4,7,10-tetraazacyclododecane-1,4,7-triyl)triacetic acid (IRM-8b)

[0072]

[0073] The intermediate compound of this example was obtained by referring to the preparation and purification method of compound IRM-8a in Example 5. ESI-MS m / z = 824.4079 [M+H] +.

[0074] Example 11 tert-Butyl 8-(2-chloroacetyl)-2,8-diazaspiro[4.5]decane-2-carboxylate (3c)

[0075]

[0076] The intermediate compound in this example can be obtained by referring to the preparation and purification methods of compound 3a in Example 1. 1 HNMR (300MHz, DMSO) δ4.35(d,J=0.9Hz,2H),3.45(d,J=19.5Hz,4H),3.28(d,J=7.1Hz,2H),3.10(s,2H),1.72( dd,J=8.6,5.2Hz,2H),1.51(t,J=4.9Hz,2H),1.43(t,J=5.6Hz,2H),1.39(s,9H).ESI-MSm / z=339.1454[M+Na] + Example 128-(2-(4-(4-(isoquinolin-4-yl)phenyl)-1H-pyrazol-1-yl)acetyl)-2,8-diazaspiro[4.5]decane-2-carboxylic acid tert-butyl ester (5c)

[0077]

[0078] By referring to the preparation and purification methods of compound 5a in Example 2, the intermediate compound in this example can be obtained. 1 HNMR(300MHz,DMSO)δ9.34(s,1H),8.47(s,1H),8.25-8.19(m,2H),7.99(s ,1H),7.93(d,J=8.5Hz,1H),7.84-7.71(m,4H),7.55(d,J=8.3Hz,2H),5.18 (s,2H),3.60-3.39(m,4H),3.32-3.25(m,2H),3.14(s,2H),1.76(t,J=6.9 Hz,2H),1.55(t,2H),1.46(t,2H),1.40(s,9H).ESI-MSm / z=552.2975[M+H] + ;574.2786[M+Na] + .

[0079] Example 13 2-(4-(4-(Isoquinolin-4-yl)phenyl)-1H-pyrazol-1-yl)-1-(2,8-diazaspiro[4.5]decan-8-yl)ethan-1-one (6c)

[0080]

[0081] By referring to the preparation and purification method of compound 6a in Example 3, the intermediate compound in this example can be obtained. 1HNMR(300MHz,DMSO)δ9.35(s,1H),8.47(s,1H),8.26-8.18(m,2H),7.99(s ,1H),7.93(d,J=8.4Hz,1H),7.78(tt,J=12.8,6.2Hz,4H),7.55(d,J=8.3Hz ,2H),5.20(s,2H),3.57-3.44(m,4H),3.31-3.25(m,2H),3.07(s,2H),1.86 (t,J=7.4Hz,2H),1.57(dt,J=13.0,6.1Hz,4H).ESI-MSm / z=452.2449[M+H] + Example 14 Tri-tert-butyl 2,2',2"-(10-(2-(8-(2-(4-(4-(isoquinolin-4-yl)phenyl)-1H-pyrazol-1-yl)acetyl)-2,8-diazaspiro[4.5]decane-2-yl)-2-oxoethyl)-1,4,7,10-tetraazacyclododecane-1,4,7-triyl)triacetate (7c)

[0082]

[0083] The intermediate compound of this example was obtained by referring to the preparation and purification method of compound 7a in Example 4. ESI-MS m / z = 1006.6160 [M+H] +.

[0084] Example 152, 2',2"-(10-(2-(8-(2-(4-(4-(isoquinolin-4-yl)phenyl)-1H-pyrazol-1-yl)acetyl)-2,8-diazaspiro[4.5]decan-2-yl)-2-oxoethyl)-1,4,7,10-tetraazacyclododecane-1,4,7-triyl)triacetic acid (IRM-8c)

[0085]

[0086] The intermediate compound of this example was obtained by referring to the preparation and purification methods of compound IRM-8a in Example 5. ESI-MS m / z = 838.4252 [M+H]+; 860.4077 [M+Na]+; 876.3737 [M+K]+.

[0087] Example 16 Radiolabeling

[0088] 68 Ga-IRM-8a-8c were prepared from IRM-8a-8c, respectively, and the mixture was adjusted with sodium acetate (1.25 M). 68 The pH value of GaCl3 solution in 0.05M hydrochloric acid was adjusted to 4.5. 10 μg of labeling precursor was added to 1 mL68 The labeled product was obtained by heating the mixture in a GaCl3 solution (pH 4.5) at 100°C for 10 min. The radiochemical purity of the product was determined by radio-thin layer scanning and was over 97%, so no further purification was required.

[0089] In vitro activity test of the compound of Example 17

[0090] IC values of the precursor compound IRM-8a-IRM-8c and the non-radioactive ligand Ga-IRM-8a-Ga-IRM-8c 50 The values are shown in Table 1 below.

[0091] Table 1 IC of compounds 50 test

[0092]

[0093] As can be seen from Table 1, under the same test conditions, the IC 50 The values were all below 1 μM, indicating that linker optimization effectively enhanced the binding ability of the ligand. Although the gallium chelates were generally less active than their precursors, they were significantly more active than the control compound Ga-10c. In particular, Ga-IRM-8c was 2.24 times more active than Ga-10c.

[0094] Example 18 68 In vivo PET / CT experiments of Ga-IRM-8a-8c in CDK19 overexpression mouse models

[0095] Radioactive tracers 68 Ga-IRM-8a–8c was used for PET / CT imaging of NOD / SCID xenograft tumors in mice. Each mouse was injected with 3.7±0.4 MBq of Ga-IRM-8a–8c via the tail vein. 68 Ga-IRM-8a, 8b, or 8c. PET images were taken at 0.5, 1, 2, and 3 hours after injection. Figure 1 The imaging results are shown, and the SUVmean values of tumor and other normal tissues were calculated from the ROI. First, all three tracers successfully delineated clear tumor lesions within 3 hours after administration. Next, the in vivo distribution of the different tracers was carefully compared using the SUVmean values. 68 The uptake of Ga-IRM-8a in the liver and kidney was significantly higher than that in the tumor, while the uptake in the heart, spleen, and stomach was comparable to that in the tumor. 68 The metabolic rate of Ga-IRM-8b in the kidney is higher than that in the liver, and the amount absorbed in the heart, liver, spleen, and stomach is almost the same as that in the tumor. 68For Ga-IRM-8c, although the liver and kidney are the main metabolic organs, the uptake of the tracer in tumors is significantly higher than that in organs such as the spleen and stomach.

[0096] To better compare the three tracers, we calculated the ratio of tumor to non-tumor tissue based on the SUVmean value ( Figure 2 ). Analysis of tumor and kidney uptake, 68 The performance of Ga-IRM-8c is 68 Ga-10c is similar to 68 Ga-IRM-8a and 68 Ga-IRM-8b performed well compared to the other two. 68 Ga-IRM-8c showed a clear advantage, which gradually increased over time and reached two times at 3 hours. 68 The tumor to lung, spleen, and stomach ratios of Ga-IRM-8c were consistently higher than those of other tracers, exceeding 2. Therefore, based on imaging efficacy and tissue safety, we believe that 68 Ga-IRM-8c has significant advantages and great potential for further research.

[0097] Example 19 68 In vivo blocking imaging and tissue distribution of Ga-IRM-8c

[0098] Blockade experiments were performed by administering a 100-fold dose of the CDK19 inhibitor BI-1347 before the injection of the labeled ligand. Tumor uptake was almost absent at 30 minutes and at 1, 2, and 3 hours, demonstrating that the radioligand 68 Ga-IRM-8c targeting specificity for CDK19 ( Figure 3 A) Resected organs and tissues from NOD / SCID mice bearing P-16 xenograft tumors. 68 Ga-IRM-8c was further subjected to biodistribution studies, and mice were euthanized 1 and 2 hours after injection ( Figure 3 B) The results were consistent with those from PET / CT imaging. In addition to the tumor, significant drug distribution was also observed in the heart, kidneys, and blood. The imaging agent was rapidly cleared from the heart, kidneys, and blood, but was metabolized more slowly in the liver and tumor. While both the liver and kidneys play a role in metabolizing the tracer, the kidneys demonstrated a more dominant role. Notably, two hours after administration, the %ID / g value at the tumor site remained close to 1, significantly higher than that in other non-target tissues, providing higher contrast and clearer imaging.

[0099] Example 20 68 PET / CT study of Ga-IRM-8c in prostate cancer patient 1

[0100] Patient 1 is a 69-year-old man with prostate cancer who developed multiple bone metastases after radical prostatectomy. The patient was undergoing castration and rezviramide therapy and recently had a pelvic mass detected on CT imaging. To further evaluate the nature of the lesion, 68 Ga-IRM-8c and 68 Ga-PSMA-11 imaging, the results are as follows Figure 4 shown. Figure 4 AB shows 68 Imaging results of Ga-IRM-8c. The drug showed high accumulation in blood vessels and kidneys, while its uptake in various solid organs was low. 68 Ga-IRM-8c provided clear visualization of the pelvic lesion, with its localization consistent with the findings from CT imaging. The maximum standardized uptake value (SUVmax) of the lesion was 3.31, significantly higher than that of the surrounding normal tissue, helping to clearly delineate the tumor margins.

[0101] Example 21 68 PET / CT study of Ga-IRM-8c in prostate cancer patients 2

[0102] Patient 2 is an 81-year-old man with early-stage prostate cancer, diagnosed with prostate cancer by needle biopsy. 68 Ga-IRM-8c was used for PET / CT imaging 60 minutes later. Figure 4 As shown in CD, the radiotracer mainly accumulated in the blood, liver, kidneys, and bladder, and no significant accumulation was observed in early prostate cancer lesions. After imaging, the patient underwent radical prostatectomy. As expected, immunohistochemical analysis of the patient's prostate cancer tissue confirmed low expression of CDK19 protein ( Figure 5 E).

[0103] Example 22 68 PET / CT study of Ga-IRM-8c in prostate cancer patients 3

[0104] Patient 3 is an 81-year-old man with prostate cancer and multiple bone metastases who is receiving a combination of enzalutamide and goserelin. Despite treatment, his prostate-specific antigen (PSA) level has been gradually increasing, prompting the use of 68 Ga-IRM-8c and 68 Ga-PSMA-11 PET / CT imaging was further studied. 68 The imaging results of Ga-IRM-8c are as follows Figure 5 As shown. Maximum intensity projection image ( Figure 5 A) shows that the drug has the highest concentrations in the kidney and bladder, consistent with its known biodistribution profile. Figure 5 B shows a direct prostate lesion, while Figure 5 C shows sacral metastatic lesions with SUVmax values of 2.93 and 2.73, respectively. 68 Ga-IRM-8c exhibited focal punctate uptake within prostate lesions, indicating enhanced specificity in detecting focal tumor sites.

[0105] In contrast, the same patient 68 Ga-PSMA-11 PET / CT imaging ( Figure 6 AC) shows diffuse uptake throughout the prostate area. This indicates 68 Ga-IRM-8c has the potential to predict local progression of prostate cancer lesions. To test this hypothesis, we performed a follow-up evaluation of the patient. Six months after the initial imaging, the patient underwent contrast-enhanced CT and transurethral prostatectomy due to worsening dysuria. Contrast-enhanced CT confirmed that the previously 68 The lesions marked by Ga-IRM-8c imaging have significantly increased in size ( Figure 6 D). Immunohistochemical analysis of resected tumor tissue showed high expression of CDK19 ( Figure 5 D), further confirming the presence and progression of prostate cancer in the identified lesion.

[0106] As an example, the present invention successfully performed PET / CT examinations on three prostate patients, including two patients with metastatic castration-resistant prostate cancer (patients 1 and 3) and one patient with primary early prostate cancer (patient 2). 68 Ga-IRM-8c detected three different lesions in patients 1 and 3, located in the pelvis, sacrum, and prostate, with SUVmax values of 3.31, 2.93, and 2.73, respectively, and corresponding tumor-to-nontumor (T / NT) ratios of 2.30, 2.59, and 2.42, respectively. 68 The lesion detection results obtained by Ga-IRM-8c were 68 The results of Ga-PSMA-11 were generally consistent, and these results were further confirmed by CT imaging and immunohistochemical staining. However, a key difference was observed. 68 The distribution of Ga-PSMA-11 in normal tissues was significantly higher than that in 68 To provide a clearer comparison, we calculated and analyzed the tissue distribution average SUVmean values of the two patients under the two tracers, as shown in Figure 2. Figure 7 shown.

[0107] 68Ga-PSMA-11 showed ultrahigh uptake in spleen and salivary glands, moderate uptake in kidney, liver, intestine and colon, and low uptake in other tissues. 68 Ga-IRM-8c is similar. In contrast, as mentioned above, 68 Ga-IRM-8c showed the highest uptake in tumors other than the kidney. It was more likely to show focal uptake in vivo. These findings highlight 68 Clinical utility of Ga-IRM-8c in detecting and delineating prostate cancer lesions, particularly in differentiating malignant sites from normal tissue. 68 The unique punctate uptake pattern of Ga-IRM-8c in prostate lesions may provide an additional diagnostic advantage, allowing for more precise localization of tumors within the prostate.

[0108] No significant signal was observed in Patient 2, who had primary early-stage prostate cancer, confirming that CDK19 expression levels are relatively low in early-stage prostate cancer. However, uptake of the CDK19 imaging agent was significantly increased in castration-resistant prostate cancer (CRPC) lesions compared with early-stage prostate cancer, and immunohistochemical analysis of CDK19 expression levels also showed consistent results. Notably, while previous reports involved database analysis and post-biopsy immunohistochemistry to determine CDK19 expression levels, this study represents the first in vivo characterization of CDK19 expression using a radioactive imaging agent and PET / CT. These results also suggest that CDK19 may be more applicable in advanced prostate cancer, consistent with previous reports. Importantly, one case of mCRPC (Patient 3) demonstrated punctate radioactive accumulation in the prostate region, with nodular changes observed on corresponding CT images. Six months later, enhanced CT scans revealed significant enlargement of the nodules, and transthoracic resection confirmed elevated CDK19 expression in the tumor region. In this patient, the CDK19 imaging agent accurately predicted local progression of prostate cancer in CRPC patients at an early stage. Corresponding PSMA imaging revealed only diffuse uptake in the prostate, likely due to high PSMA expression in benign lesions such as prostatic hyperplasia, where the highly concentrated prostate tissue obscures the visualization of these lesions. Therefore, we believe these human imaging results demonstrate the superiority of CDK19 imaging agents in detecting advanced prostate cancer lesions. Furthermore, as highlighted by existing studies, approximately 20% of PSMA-negative tumors cannot be accurately detected. Preliminary CDK19 PET / CT imaging results suggest that CDK19 may serve as a valuable augmentative or complementary target to PSMA.

[0109] In summary, the three new PET imaging agents provided by the present invention are 68Ga-IRM-8a-8c has good in vitro stability, obvious imaging effect, and high affinity and specificity for CDK19. Further preclinical animal experiments and PET / CT imaging of prostate cancer patients have confirmed that it can be used as a potential tool for monitoring CDK19 expression levels in vivo and exploring the mechanism of prostate cancer and clinical diagnosis.

[0110] It should be understood that the above-described specific embodiments of the present invention are merely illustrative of the invention or explanation of the principles of the present invention, and do not constitute limitations of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included within the scope of protection of the present invention. In addition, the appended claims are intended to cover all variations and modifications that fall within the scope and metes and bounds of the appended claims, or equivalents of such scope and metes and bounds.

Claims

1. Category I 68 Ga-labeled tumor imaging agents:

2. The tumor imaging agent according to claim 1, comprising a prodrug and a radionuclide 68 Ga was prepared, and its prodrug structure is as follows:

3. The method for preparing the compound according to claim 1, characterized in that: 1) 2-Chloroacetyl chloride was coupled with the linker compound (2a-2c) in DCM at room temperature using triethylamine as a base to obtain the intermediate compound 3a-3c in high yield; 2) Compounds 3a-3c and compound 4 were coupled at room temperature in the presence of potassium carbonate and acetonitrile to give compounds 5a-5c; 3) Removal of BOC protection under TFA and DCM conditions to give compounds 6a-6c; 4) Compounds 6a-6c obtained in step 3) were reacted with tri-tert-butyl 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid in the presence of HATU and DIPEA to undergo an acid ammonium condensation reaction to obtain compounds 7a-7c; 5) hydrolyzing the compounds 7a-7c obtained in step 4) under acidic conditions to obtain labeled precursor compounds IRM-8a-8c; 6) The labeled precursor compound IRM-8a-8c obtained in step 5) is mixed with water. 68 GaCl3 complexation can produce radiolabeled compounds 68 Ga-IRM-8a-8c.

4. Use of the tumor imaging agent and / or its pharmaceutically acceptable salt and pharmaceutical composition according to claim 1 in the preparation of a radionuclide reagent.

5. The use according to claim 4, wherein the radionuclide agent targets cyclin-dependent kinase. The use according to claim 5 , wherein the cyclin-dependent kinase is CDK19.

7. The use according to claim 6, which is used in the preparation of a radionuclide reagent for cancers with high CDK19 expression.

8. The use according to claim 7, wherein the radionuclide agent is used in the preparation of a radionuclide agent for prostate cancer with high CDK19 expression.

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