Gastrin-releasing peptide receptor (GRPR)-targeted compounds and uses thereof

Abstract

The present invention relates to gastrin-releasing peptide receptor (GRPR)-targeted compounds and their use for imaging and treatment of diseases or conditions characterized by expression of the gastrin-releasing peptide receptor.

Description

GASTRIN-RELEASING PEPTIDE RECEPTOR (GRPR)-TARGETED COMPOUNDS AND USES THEREOF CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No.63 / 694,257, filed on September 13, 2024, the contents of which is hereby incorporated by reference in its entirety for all purposes. REFERENCE TO AN ELECTRONIC SEQUENCE LISTING

[0002] The contents of the electronic sequence listing (A9TH_025_01WO_SeqList_ST26.xml; Size: 218,099 bytes; and Date of Creation: September 11, 2025) are herein incorporated by reference in its entirety. FIELD

[0003] The present invention relates to gastrin-releasing peptide receptor (GRPR)-targeted compounds and their use for imaging and treatment of diseases or conditions characterized by expression of the gastrin-releasing peptide receptor. BACKGROUND

[0004] Gastrin-releasing peptide receptor (GRPR) is a G protein-coupled receptor of the bombesin (BBN) receptor family (Roesler & Schwartsmann. 2012. Front Endocrinol (Lausanne) 3:159; Bitar & Zhu.1993. Gastroenterology.105:1672-1680; Weber.2009. Curr Opin Endocrinol Diabetes Obes. 16:66-71). Together with its endogenous ligand, gastrin-releasing peptide (GRP), GRPR is involved in synaptic plasticity, emotional and feeding behavior, hormone secretion, smooth muscle contraction, and cell proliferation (ibid.). In normal conditions, the expression of GRPR is restricted to the central nervous system, pancreas, adrenal cortex and gastrointestinal tract (Jensen, et al. 2008. Pharmacol Rev. 60:1-42). GRPR is also implicated in neoplastic progression, with overexpression of GRPR having been reported in many cancer subtypes including lung, head and neck, colon, kidney, ovarian, breast and prostate cancers (Cornelio, et al. Ann Oncol.2007, 18:1457-1466). This ectopic expression in cancers makes it an attractive target for personalized therapies.

[0005] BBN is a 14 amino acid GRPR binding peptide (Lin, et al. 2004. Bioconjugate Chemistry. Vol 15. American Chemical Society pages 1416-1423; Inkster, et al. 2013 Bioorganic Med Chem Lett.23:3920-3926; Mansi, et al.2016 J Nucl Med.57:67S-72S; Bodei, et al.2007.177Lu-AMBA Bombesin analogue in hormone refractory prostate cancer patients: a phase I escalation study with single-cycle administrations. In: JOINT EANM-EORTCSymposium; Sah, et al. 2015 J Nucl Med. 56:372-378; Zang, et al. 2018 Clin Nucl Med. 43:663-669; Nock, et al.2017 J Nucl Med.58:75-80; Maina, et al.2016 Eur J Nucl Med Mol Imaging 43:964-973). BBN derivatives have been radiolabeled for imaging with single photon emission computed tomography (SPECT), positron emission tomography (PET), and have also been radiolabeled for therapy with beta and alpha emitters (Maina, et al. PET Clin. 2017;12:297-309; Lin, et al. 2004. Bioconjugate Chemistry. Vol 15. American Chemical Society pages 1416-1423; Inkster, et al. 2013 Bioorganic Med Chem Lett. 23:3920-3926). Often, a radiolabelled group is appended directly onto the structure or via a linker at the N-terminus, while modifications at the C-terminus dictate agonist / antagonist properties. For targeting GRPR, antagonists are preferred since agonists have been shown to induce gastrointestinal adverse events (Bodei, et al. 2007.177Lu-AMBA Bombesin analogue in hormone refractory prostate cancer patients: a phase I escalation study with single-cycle administrations. In: JOINT EANM-EORTC Symposium). Examples of GRPR antagonists evaluated in the clinic include:68Ga-RM2,68Ga-SB3,68Ga-NeoBOMB1,68Ga-RM26,18F-BAY-864367, and64Cu-CB-TE2A-AR06 (Mansi, et al.2016 J Nucl Med.57:67S-72S; Sah, et al.2015 J Nucl Med.56:372-378; Zang, et al.2018 Clin Nucl Med.43:663-669; Nock, et al. 2017 J Nucl Med. 58:75-80; Maina, et al. 2016 Eur J Nucl Med Mol Imaging 43:964-973; Kahkonen, et al. Clin Cancer Res. 2013;19:5434-5443, Kahkonen, et al. Clin Cancer Res. 2013;19:5434-5443; Baum, et al.2007 Journal of Nuclear Medicine 48, 79P-79P). However, high pancreas uptake remains the major limitation of currently reported GRPR-targeting radioligands.

[0006] In a study, the high pancreas uptake of68Ga-labeled AMBA was up to 54.9 SUV (SUV: standard uptake value) (Baum, et al. 2007 Journal of Nuclear Medicine 48, 79P-79P). In addition,68Ga-labeled RM2 was also reported to show high uptake in pancreas (Kurth, et al. 2020. European journal of nuclear medicine and molecular imaging 47, 123-135; Minamimoto, et al.2016 J Nucl Med.57:557-562). It has also been reported that radiolabeled NeoBOMB1 showed high pancreas uptake in both PC-3 tumor-bearing mice and prostate cancer patients (Nock, et al.2017 J Nucl Med.58:75-80).

[0007] Another limitation for most of the reported GRPR-targeting ligands is their in vivo metabolic instability (Bakker, et al. 2018 Molecular imaging and biology 20, 973-983; Rousseau, et al.2020 Journal of Labelled Compounds and Radiopharmaceuticals 63, 56-64) due to enzymatic degradation by neutral endopeptidase (NEP) (Nock, et al.2014 J Nucl Med. 55:121-127). His12-Leu13, Trp8-Ala9and Gln7-Trp8were reported to be the main cleavage sites within the AMBA’s sequence, and Trp8-Ala9, Ala9-Val10and Gln7-Trp8were considered to be the cleavage sites of RM2 (Kahkonen, et al.2013 Clin Cancer Res.19:5434-5443; Linder et al.2009 Bioconjugate chemistry 20, 1171-1178).

[0008] A series of bombesin analogs modifying its C-terminal Leu13-Met14have beendeveloped. See, Rousseau, E. et al. Journal of Labelled Compounds and Radiopharmaceuticals 63, 56-64 (2020), Lau, J. et al. ACS omega 4, 1470-1478 (2019), and Bratanovic, I. J. et al. J. of Nuclear Medicine July 2021, jnumed.120.257758, each of which is hereby incorporated by reference in its entirety for all purposes. However, there still remain a need in the field for improved tracers for the non-invasive in-vivo imaging of the GRPR. Such tracers are useful for the diagnosis of disorders related to aberrant / ectopic expression of GRPR, including but not limited to cancer (e.g., prostate cancer). There also remains an unmet need for improved radiotherapeutic agents for treatment of diseases / disorders related to aberrant / ectopic expression of GRPR, including but not limited to cancer (e.g., prostate cancer). In particular, there is a need for GRPR-targeting radioligands (for imaging and / or therapy) with lower pancreas uptake, and useful stability in vivo.

[0009] No admission is necessarily intended, nor should it be construed, that any of the preceding information constitutes prior art against the present invention. SUMMARY

[0010] In one aspect, this disclosure provides a peptidic compound of Formula (A), or a salt or solvate thereof: Rradn6-RL-[linker]-RL-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-[ψ-Xaa9-(Xaa10)m2]m1-R (A) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI,2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; Xaa8is statine (Sta), Leu, D-Pro, Phe, cis-4-NHRa-D-Pro or cis-4-ORa-D-Pro, wherein Rais alkyl, cycloalkyl, or aryl; R is -NH2or -NHOH; m1 is 0 or 1; m2 is 0 or 1; when m1 is 1 and m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m1 is 1 and m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, Me2Thz (5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; each RLis independently absent, –(C1-6alkyl)-, –(C1-6alkyl)-C(O)–, –C(O)–, –NH–C(O)–, or –NH–C(S)–; the linker is a linear or branched chain of n1 units of -Xaa11-, and / or –L1R1– and / or –(L1)2R1–, wherein: n1 is 1-20; each Xaa11is independently an amino acid; each R1is, independently, a linear, branched, and / or cyclic C1-20alkylenyl, alkenylenyl and / or alkynylenyl, wherein any carbon bonded to two other carbons is optionally independently replaced by N, S, or O, and carbons are optionally independently substituted with oxo, hydroxyl, sulfhydryl, -SeH, halogen, guanidino, amine, amide, urea, carboxylic acid, sulfonic acid, sulfinic acid, or phosphoric acid; L1bonds to carbon, wherein each L1is independently –S–, –N(R2)C(O)–,–C(O)N(R2)–, –NH–C(O)–NH–, –NH–C(S)–NH–, , , ,or ; and R2is H, methyl or ethyl; optionally, the linker comprises an albumin binder (Ralb), wherein the albumin binder is:-(CH2)n3-CH3wherein n3 is 8-20; -(CH2)n4-C(O)OH wherein n4 is 8-20;wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl;wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; orn6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; wherein: (i) Xaa3is αMe-Trp, provided that the compound is not AMTG, AMTG2, and / or LW01186 (DOTA-Pip-D-Phe-Gln-αMe-Trp-Ala-Tle-Gly-His-Leu-ψ-Thz-NH2(SEQ ID NO: 1)); (ii) Xaa7is Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); (iii) Xaa2is Gly, Arg, Asp, Glu, citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), or 2-amino-4-guanidinobutyric acid (Agb); (iv) m2 is 1; (v) at least one Rradis CROWN, CROWNGA, TCMC, PSC, a prosthetic group containing a trifluoroborate, an aryl or heteroaryl substituted with at least one radiohalogen, or an aryl or heteroaryl substituted with at least one fluorineprecursor leaving group; (vi) m1 is 0; or (vii) any combinations of (i)-(vi); and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated.

[0011] In another aspect, this disclosure provides a peptidic compound of Formula (B-1), or a salt or solvate thereof: Rrad-[linker]-Xaa13-[Xaa12-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-ψ-Xaa9-(Xaa10)m2-R]2(B-1) wherein: Xaa12is an N-terminal amino acid residue selected from p-aminomethylaniline-diglycolic acid (pABzA-DIG), 4-amino-(1-carboxymethyl)piperidine (Pip), 9-amino-4,7-dioxanonanoic acid (dPEG2), or 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp); Xaa1is D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is statine (Sta), Leu, D-Pro, or Phe; R is -NH2or -NHOH; m2 is 0 or 1;when m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; Xaa13is an amino acid with a sidechain comprising a carboxylic acid, wherein one Xaa12is bonded to the C-terminus of Xaa13and the other Xaa12is bonded to the sidechain of Xaa13; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; the linker absent or is a linear or branched chain of n1 units of -Xaa11-, wherein: n1 is 1-6; each Xaa11is independently an amino acid; Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated.

[0012] In still another aspect, the disclosure provides a composition comprising any one of the peptidic compounds as described herein and a pharmaceutically acceptable carrier or excipient.

[0013] In a further aspect, the disclosure provides a method of imaging gastrin-releasing peptide receptor (GRPR)-expressing tissue in a subject, the method comprising administering to the subject any one of the peptidic compounds described herein or compositions thereof, and imaging tissue of the subject.

[0014] In an additional aspect, the disclosure provides a method of treating cancer in a subject comprising, administering to the subject in need thereof a therapeutically effective amount of any one of the peptidic compounds described herein or compositions thereof. DETAILED DESCRIPTION

[0015] As used herein, the terms “comprising,” “having”, “including” and “containing,” andgrammatical variations thereof, are inclusive or open-ended and do not exclude additional, unrecited elements and / or method steps, even if a feature / component defined as a part thereof consists or consists essentially of specified feature(s) / component(s). The term “consisting essentially of” if used herein in connection with a compound, composition, use or method, denotes that additional elements and / or method steps may be present, but that these additions do not materially affect the manner in which the recited compound, composition, method or use functions. The term “consisting of” if used herein in connection with a feature of a compound, composition, use or method, excludes the presence of additional elements and / or method steps in that feature. A compound, composition, use or method described herein as comprising certain elements and / or steps may also, in certain embodiments consist essentially of those elements and / or steps, and in other embodiments consist of those elements and / or steps, whether or not these embodiments are specifically referred to. A use or method described herein as comprising certain elements and / or steps may also, in certain embodiments consist essentially of those elements and / or steps, and in other embodiments consist of those elements and / or steps, whether or not these embodiments are specifically referred to.

[0016] A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the elements is present, unless the context clearly requires that there be one and only one of the elements. The singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. The use of the word “a” or “an” when used herein in conjunction with the term “comprising” may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one” and “one or more than one.”

[0017] The term “about” can mean within an acceptable error range for the particular value as determined by one of ordinary skill in the art, which will depend in part on how the value is measured or determined, i.e., the limitations of the measurement system. For example, “about” can refer to a range of ±20%, ±15%, ±10%, ±5%, or ±1% of a given value.

[0018] In this disclosure, the recitation of numerical ranges by endpoints includes all numbers subsumed within that range including all whole numbers, all integers and, where suitable, all fractional intermediates (e.g., 1 to 5 may include 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5 etc.).

[0019] Unless otherwise specified, “certain embodiments”, “various embodiments”, “an embodiment” and similar terms includes the particular feature(s) described for that embodiment either alone or in combination with any other embodiment or embodiments described herein, whether or not the other embodiments are directly or indirectly referenced and regardless of whether the feature or embodiment is described in the context of a method, product, use, composition, compound, et cetera.

[0020] As used herein, the terms “treat”, “treatment”, “therapeutic” and the like includes ameliorating symptoms, reducing disease progression, improving prognosis and reducingrecurrence.

[0021] As used herein, the term “diagnostic agent” includes an “imaging agent”. As such, a “diagnostic radionuclide” includes radionuclides that are suitable for use in imaging agents.

[0022] The term “subject” refers to an animal (e.g., a mammal or a non-mammal animal). The subject may be a human or a non-human primate. The subject may be a laboratory mammal (e.g., mouse, rat, rabbit, hamster and the like). The subject may be an agricultural animal (e.g., equine, ovine, bovine, porcine, camelid and the like) or a domestic animal (e.g., canine, feline and the like). In some embodiments, the subject is a human.

[0023] The compounds disclosed herein may also include base-free forms, solvates, salts or pharmaceutically acceptable salts thereof. Unless otherwise specified or indicated, the compounds claimed and described herein are meant to include all racemic mixtures and all individual enantiomers or combinations thereof, whether or not they are explicitly represented herein.

[0024] The compounds disclosed herein may be shown as having one or more charged groups, may be shown with ionizable groups in an uncharged (e.g., protonated) state or may be shown without specifying formal charges. As will be appreciated by a person of skill in the art, the ionization state of certain groups within a compound (e.g., without limitation, COOH, and the like) is dependent, inter alia, on the pKa of that group and the pH at that location. For example, but without limitation, a carboxylic acid group (i.e. COOH) would be understood to usually be deprotonated (and negatively charged) at neutral pH and at most physiological pH values, unless the protonated state is stabilized.

[0025] As used herein, the terms “salt” and “solvate” have their usual meaning in chemistry. As such, when the compound is a salt or solvate, it is associated with a suitable counter-ion. It is well known in the art how to prepare salts or to exchange counter-ions. Generally, such salts can be prepared by reacting free acid forms of these compounds with a stoichiometric amount of a suitable base (e.g., without limitation, Na, Ca, Mg, or K hydroxide, carbonate, bicarbonate, or the like), or by reacting free base forms of these compounds with a stoichiometric amount of a suitable acid. Such reactions are generally carried out in water or in an organic solvent, or in a mixture of the two. Counter-ions may be changed, for example, by ion-exchange techniques such as ion-exchange chromatography. All zwitterions, salts, solvates and counter-ions are intended, unless a particular form is specifically indicated.

[0026] In certain embodiments, the salt or counter-ion may be pharmaceutically acceptable, for administration to a subject. As used herein, “pharmaceutically acceptable” means suitable for in vivo use in a subject, and is not necessarily restricted to therapeutic use, but also includes diagnostic use. More generally, with respect to any pharmaceutical composition disclosed herein, non-limiting examples of suitable excipients include any suitable buffers, stabilizing agents, salts, antioxidants, complexing agents, tonicity agents, cryoprotectants,lyoprotectants, suspending agents, emulsifying agents, antimicrobial agents, preservatives, chelating agents, binding agents, surfactants, wetting agents, non-aqueous vehicles such as fixed oils, or polymers for sustained or controlled release. See, for example, Berge et al.1977. (J. Pharm Sci.66:1-19), or Remington– The Science and Practice of Pharmacy, 21st edition (Gennaro et al editors. Lippincott Williams & Wilkins Philadelphia), each of which is incorporated by reference in its entirety.

[0027] As used herein, the expression “Cn” where n is an integer (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,17, 18, 19, 20, and the like) or where n is defined as a range of integers (e.g., 1-20, 1-18, 2-15, 3-20, and the like) refers to the number of carbons in a compound, R-group, L-group, or substituent, or refers to the number of carbons plus heteroatoms in a compound, R-group, L-group, or substituent. A range of integers includes all integers in the range; e.g., the range 1-20 includes the integers 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20. Unless otherwise defined, heteroatoms may include any, some or all possible heteroatoms. For example, in some embodiments, the heteroatoms may be selected from N, O, S, P and Se. In some embodiments, the heteroatoms are selected from N, S, or O. Such embodiments are non-limiting. The alternative expression “Cy-Cz”, where y and z are integers (e.g., C3-C15and the like), is equivalent to “Cn” where n is a range of integers from y to z.

[0028] The terms “alkyl”, “alkylenyl”, “alkenylenyl”, and “alkynylenyl” have their usual meanings in organic chemistry. For example, an “alkyenylenyl” has at least one carbon-carbon double bond, and may have any number of carbon-carbon single bonds. Similarly, an “alkynylenyl” has at least one carbon-carbon triple bond, and may have any number of carbon-carbon single bonds. The expressions “alkylenyl, alkenylenyl and / or alkynylenyl” and “alkylenyl, alkenylenyl or alkynylenyl” are intended to be equivalent and each includes hydrocarbon chains that can have any reasonable number or combination of carbon-carbon single bonds, double bonds, and triple bonds. These hydrocarbon chains can be linear, branched, cyclic, or any combination of linear and branched, linear and cyclic, cyclic and branched, branched and cyclic, or linear, branched and cyclic. Cyclic hydrocarbons may be nonaromatic, partially aromatic, or aromatic. Unless otherwise specified, the term “cyclic” includes single rings, multiple non-fused rings, fused rings, bridged rings, and combinations thereof.

[0029] The expression “wherein any carbon … is optionally independently replaced by N, S, or O” and other similar expressions means that the defined hydrocarbon (e.g., “alkyl”, “alkylenyl”, “alkenylenyl”, or “alkynylenyl”) includes zero, one, more than one, or any reasonable combination of two or more heteroatoms selected from N, S, and O. The above expression therefore expands the defined hydrocarbon to additionally encompass heteroalkyls, heteroalkylenyls, heteroalkenylenyls, and heteroalkynylenyls, etc. A person ofskill in the art would understand that various combinations of different heteroatoms may be used. The expression “wherein any carbon bonded to two other carbons is optionally independently replaced by N, S, or O” and other similar expressions means that any carbon in the defined hydrocarbon bonded to two other carbons (e.g., the underlined carbon in -C-C-C-), whether those bonds are single, double, or triple bonds, may be a heteroatom, but excludes heteroatoms bonded to other heteroatoms (e.g., excludes -C-N-S-, -S-S-N-, -N-S-C-, and the like).

[0030] Various R-groups (e.g., R1, R2, R3, etc.) and L-groups (e.g., L1, L2, L3, etc.) are defined in this disclosure. Some groups are divalent (e.g., –S–, –NH–C(O)–, –C(O)–NH–, –N(alkyl)–C(O)–, –C(O)–N(alkyl)–, –NH–C(O)–NH–, –NH–C(S)–NH–, , ,, or ).

[0031] If unspecified, the size of an R-group or L-group is what would be considered reasonable to a person of skill in the art. For example, but without limitation, if unspecified, the size of an alkyl may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or more than 20 carbons in length, subject to the common general knowledge of the person of skill in the art. Further, but without limitation, if unspecified, the size of a heteroalkyl may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or more than 20 carbons and heteroatoms in length, subject to the common general knowledge of the person of skill in the art. In the context of the expression “alkyl, alkenyl or alkynyl” and similar expressions, the “alkyl” would be understood to be a saturated alkyl, and the “alkenyl” and the “alkynyl” would be understood to be unsaturated.

[0032] As used herein, in the context of an alkyl / heteroalkyl group of a compound, the term “linear” may be used as it is normally understood to a person of skill in the art and generally refers to a chemical entity that comprises a skeleton or main chain that does not split off into more than one contiguous chain. Non-limiting examples of linear alkyls include methyl, ethyl, n-propyl, and n-butyl.

[0033] As used herein, the term “branched” may be used as it is normally understood to a person of skill in the art and generally refers to a chemical entity that comprises a skeleton or main chain that splits off into more than one contiguous chain. The portions of the skeleton or main chain that split off in more than one direction may be linear, cyclic or any combination thereof. Non-limiting examples of a branched alkyl group include tert-butyl and isopropyl.

[0034] The term “alkylenyl” refers to a divalent analog of an alkyl group. In the context of the expression “alkylenyl, alkenylenyl and / or alkynylenyl”, and similar expressions, the “alkylenyl”would be understood to be a saturated alkylenyl, and the “alkenylenyl” and the “alkynylenyl” would be understood to be unsaturated. The term “heteroalkylenyl” refers to a divalent analog of a heteroalkyl group. The term “heteroalkenylenyl” refers to a divalent analog of a heteroalkenyl group. The term “heteroalkynylenyl” refers to a divalent analog of a heteroalkynyl group.

[0035] As used herein, the term “saturated” when referring to a chemical entity may be used as it is normally understood to a person of skill in the art and generally refers to a chemical entity that comprises only single bonds, and may include linear, branched, and / or cyclic groups. Non-limiting examples of a saturated C1-C20alkyl group may include methyl, ethyl, n-propyl, i-propyl, sec-propyl, n-butyl, i-butyl, sec-butyl, t-butyl, n-pentyl, i-pentyl, sec-pentyl, t-pentyl, n-hexyl, i-hexyl, 1,2-dimethylpropyl, 2-ethylpropyl, 1-methyl-2-ethylpropyl, l-ethyl-2-methylpropyl, 1,1,2-trimethylpropyl, 1,1,2-triethylpropyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 2-ethylbutyl, 1,3-dimethylbutyl, 2-methylpentyl, 3-methylpentyl, sec-hexyl, t-hexyl, n-heptyl, i-heptyl, sec-heptyl, t-heptyl, n-octyl, i-octyl, sec-octyl, t-octyl, n-nonyl, i-nonyl, sec-nonyl, t-nonyl, n-decyl, i-decyl, sec-decyl, t-decyl, cyclopropanyl, cyclobutanyl, cyclopentanyl, cyclohexanyl, cycloheptanyl, cyclooctanyl, cyclononanyl, cyclodecanyl, and the like. Unless otherwise specified, a C1-C20alkylenyl therefore encompasses, without limitation, all divalent analogs of the above-listed saturated alkyl groups.

[0036] As used herein, the term “unsaturated” when referring to a chemical entity may be used as it is normally understood to a person of skill in the art and generally refers to a chemical entity that comprises at least one double or triple bond, and may include linear, branched, and / or cyclic groups. Non-limiting examples of a C2-C20alkenyl group may include vinyl, allyl, isopropenyl, l-propene-2-yl, 1-butene-l-yl, l-butene-2-yl, l-butene-3-yl, 2-butene-l-yl, 2-butene-2-yl, octenyl, decenyl, cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, cyclooctenyl, cyclononanenyl, cyclodecanenyl, and the like. Unless otherwise specified, a C1-C20alkenylenyl therefore encompasses, without limitation, all divalent analogs of the above-listed alkenyl groups. Non-limiting examples of a C2-C20alkynyl group may include ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl, octynyl, nonynyl, decynyl, and the like. Unless otherwise specified, a C1-C20alkynylenyl therefore encompasses, without limitation, all divalent analogs of the above-listed alkynyl groups.

[0037] Non-limiting examples of non-aromatic cyclic groups include cylcopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and the like. Non-limiting examples of non-aromatic heterocyclic groups include aziridinyl, azetidinyl, diazetidinyl, pyrrolidinyl, pyrrolinyl, piperidinyl, piperazinyl, imidazolinyl, pyrazolidinyl, imidazolydinyl, phthalimidyl, succinimidyl, oxiranyl, tetrahydropyranyl, oxetanyl, dioxanyl, thietanyl, thiepinyl, morpholinyl, oxathiolanyl, and the like.

[0038] Unless further specified, an “aryl” group includes both single aromatic rings as well asfused rings containing at least one aromatic ring. non-limiting examples of C3-C20aryl groups include phenyl (Ph), pentalenyl, indenyl, naphthyl and azulenyl. Non-limiting examples of aromatic heterocyclic groups of similar size include pyrrolyl, imidazolyl, pyrazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pirazinyl, quinolinyl, isoquinolinyl, acridinyl, indolyl, isoindolyl, indolizinyl, purinyl, carbazolyl, indazolyl, phthalazinyl, naphthyridinyl, quinoxalinyl, quinazolinyl, cinnolinyl, pteridinyl, phenanthridinyl, phenazinyl, phenanthrolinyl, perimidinyl, furyl, dibenzofuryl, xanthenyl, benzofuryl, thiophenyl, thianthrenyl, benzothiophenyl, phosphorinyl, phosphinolinyl, phosphindolyl, thiazolyl, oxazolyl, isoxazolyl, and the like.

[0039] As used herein, the term “substituted” is used as it would normally be understood to a person of skill in the art and generally refers to a compound or chemical entity that has one chemical group replaced with a different chemical group. Unless otherwise specified, a substituted alkyl, alkylenyl, alkenylenyl, or alkynylenyl has one or more hydrogen atom(s) independently replaced with an atom that is not hydrogen. For example, chloromethyl is a non-limiting example of a substituted alkyl, more particularly an example of a substituted methyl. Aminoethyl is another non-limiting example of a substituted alkyl, more particularly an example of a substituted ethyl. Unless otherwise specified, a substituted compound or group (e.g., R-group or L-group) may be substituted with any chemical group reasonable to a person of skill in the art. For example, but without limitation, a hydrogen bonded to a carbon or heteroatom (e.g., N) may be substituted with halide (e.g., F, I, Br, Cl), amine, amide, oxo, hydroxyl, thiol, phosphate, phosphonate, sulfate, SO2H, SO3H, alkyls, heteroalkyls, aryl, heteroaryl, ketones, carboxaldehyde, carboxylates, carboxamides, nitriles, monohalomethyl, dihalomethyl or trihalomethyl. In some embodiments, each carbon may be independently substituted or unsubstituted with oxo, hydroxyl, sulfhydryl, amine, amide, urea, halogen, guanidino, carboxylic acid, sulfonic acid, sulfinic acid, or phosphoric acid. In some embodiments, the amide substituent is –C(O)-NH2.

[0040] As used herein, the term “unsubstituted” is used as it would normally be understood to a person of skill in the art. Non-limiting examples of unsubstituted alkyls include methyl, ethyl, tert-butyl, pentyl and the like. The expression “optionally substituted” is used interchangeably with the expression “unsubstituted or substituted”. The expression “optionally independently substituted” means that each location may be substituted or may not be substituted, and when substituted each substituent may be the same or different.

[0041] In the structures provided herein, hydrogen may or may not be shown. In some embodiments, hydrogens (whether shown or implicit) may be protium (i.e.1H), deuterium (i.e.2H) or combinations of1H and2H. Methods for exchanging1H with2H are well known in the art. For solvent-exchangeable hydrogens, the exchange of1H with2H occurs readily in the presence of a suitable deuterium source, without any catalyst. The use of acid, base or metal catalysts, coupled with conditions of increased temperature and pressure, can facilitate theexchange of non-exchangeable hydrogen atoms, generally resulting in the exchange of all1H to2H in a molecule.

[0042] The term “Xaa” refers to an amino acid residue in a peptide chain or an amino acid that is otherwise part of a compound. Amino acids have both an amino group and a carboxylic acid group, either or both of which can be used for covalent attachment. In attaching to the remainder of the compound, the amino group and / or the carboxylic acid group may be converted to an amide or other structure; e.g., a carboxylic acid group of a first amino acid is converted to an amide (i.e. a peptide bond) when bonded to the amino group of a second amino acid. As such, Xaa may have the formula –N(Ra)RbC(O)–, where Raand Rbare R-groups. Rawill typically be hydrogen or alkyl (e.g., methyl) or Raand Rbmay form a cyclic structure. The amino acid residues of a peptide may comprise typical peptide (amide) bonds and may further comprise bonds between side chain functional groups and the side chain or main chain functional group of another amino acid. For example, the side chain carboxylate of one amino acid residue in the peptide (e.g., Asp, Glu, etc.) may be bonded to and the amine of another amino acid residue in the peptide (e.g., Dap, Dab, Orn, Lys). Further details are provided below. Unless otherwise indicated, “Xaa” may be any amino acid, including a proteinogenic or nonproteinogenic amino acid. Non-limiting examples of nonproteinogenic amino acids are shown in Table A and include: D-amino acids (including without limitation any D-form of the following amino acids), ornithine (Orn), 3-(1-naphtyl)alanine (Nal), 3-(2-naphtyl)alanine (2-Nal), α^aminobutyric acid, norvaline, norleucine (Nle), homonorleucine, beta-(1,2,3-triazol-4-yl)-L-alanine, 1,2,4-triazole-3-alanine, Phe(4-F), Phe(4-Cl), Phe(4-Br), Phe(4-I), Phe(4-NH2), Phe(4-NO2), homoarginine (hArg), 2-amino-4-guanidinobutyric acid (Agb), 2-amino-3-guanidinopropionic acid (Agp), Β-alanine, 4-aminobutyric acid, 5-aminovaleric acid, 6-aminohexanoic acid, 7-aminoheptanoic acid, 8-aminooctanoic acid, 9-aminononanoic acid, 10-aminodecanoic acid, 2-aminooctanoic acid, 2-amino-3-(anthracen-2-yl)propanoic acid, 2-amino-3-(anthracen-9-yl)propanoic acid, 2-amino-3-(pyren-1-yl)propanoic acid, Trp(5-Br), Trp(5-OCH3), Trp(6-F), Trp(5-OH) or Trp(CHO), 2-aminoadipic acid (2˗Aad), 3-aminoadipic acid (3˗Aad), propargylglycine (Pra), homopropargylglycine (Hpg), beta-homopropargylglycine (Bpg), 2,3-diaminopropionic acid (Dap), 2,4-diaminobutyric acid (Dab), azidolysine (Lys(N3)), azido-ornithine (Orn(N3)), 2-amino-4-azidobutanoic acid Dab(N3), Dap(N3), 2-(5'-azidopentyl)alanine, 2-(6'-azidohexyl)alanine, 4-amino-1-carboxymethyl-piperidine (Pip), 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp), tranexamic acid, tert-leucine (Tle), 4-chlorophenylalanine (Cpa), thiazoline-4-carboxylic acid (Thz), αMe-Trp, p-aminomethylaniline-diglycolic acid (pABzA-DIG), 4-amino-1-carboxymethyl-piperidine (Pip), NH2(CH2)2O(CH2)2C(O)OH, NH2(CH2)2[O(CH2)2]2C(O)OH (dPEG2), NH2(CH2)2[O(CH2)2]3C(O)OH, NH2(CH2)2[O(CH2)2]4C(O)OH, NH2(CH2)2[O(CH2)2]5C(O)OH,NH2(CH2)2[O(CH2)2]6C(O)OH, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (diFPro), statine (Sta), β-(3-benzothienyl)alanine (Bta), citrulline (Cit), Trp(Me), Trp (7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(5-F), Trp(4-F) or cyclopentylglycine (Cpa). If not specified as an L- or D-amino acid, then the amino acid includes both L- and D-amino acid. If an unspecified (with respect to L- or D-) amino acid is listed together with its corresponding D-amino acid (e.g., Pro and D-Pro), then the unspecified amino acid is understood to be an L-amino acid.

[0043] TABLE A. List of non-limiting examples of non-proteinogenic amino acids.

[0044] The wavy line “ ” symbol shown through or at the end of a bond in a chemicalformula (e.g., in the definitions L1or RAof Formula I) is intended to define the group on one side of the wavy line, without modifying the definition of the structure on the opposite side of the wavy line. Where an R-group or L-group is bonded on two or more sides, any atoms shown outside the wavy lines are intended to clarify orientation of the defined group. As such, only the atoms between the two wavy lines constitute the definition of the R-group or L-group. When atoms are not shown outside the wavy lines (e.g., L1), or for a chemical group shown without wavy lines but does have bonds on multiple sides (e.g., –C(O)NH–, and the like), the chemical group should be read from left to right matching the orientation in the formula that the group relates to; e.g., for formula –Ra–Rb–Rc–, the definition of Rbas –C(O)NH– would be incorporated into the formula as –Ra–C(O)NH–Rc– not as –Ra–NHC(O)–Rc–.

[0045] The term “therapeutically effective amount” as used herein refers to an amount effective at the dosage and duration necessary to achieve the desired therapeutic result. A therapeutically effective amount of the composition may vary depending on factors such as the individual’s condition, age, sex, and weight, and the ability of the protein to elicit the desired response of the individual. A therapeutically effective amount can also be an amountthat exceeds any toxic or deleterious effect of the composition that would have a beneficial effect on the treatment. Compounds

[0046] Previously, a series of bombesin analogs modifying its C-terminal Leu13-Met14have been developed. See, Rousseau, E. et al. Journal of Labelled Compounds and Radiopharmaceuticals 63, 56-64 (2020), Lau, J. et al. ACS omega 4, 1470-1478 (2019), and Bratanovic, I. J. et al. J. of Nuclear Medicine July 2021, jnumed.120.257758, each of which is hereby incorporated by reference in its entirety for all purposes.

[0047] In one aspect, this disclosure provides a peptidic compound of Formula (A), (I), (IA), (IA-1), (IB), (IB-1), (IC), (IC-1), (ID), (ID-1), (IE), (IE-1), (IF), (IF-1), (II), (IIA), (B), or (B-1) (each as defined below), or a salt or solvate thereof.

[0048] In some embodiments, the present disclosure relates to a peptidic compound of Formula (A), or a salt or solvate of Formula (A), Rradn6-RL-[linker]-RL-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-[ψ-Xaa9-(Xaa10)m2]m1-R (A) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala);Xaa8is statine (Sta), Leu, D-Pro, Phe, cis-4-NHRa-D-Pro or cis-4-ORa-D-Pro, wherein Rais alkyl, cycloalkyl, or aryl; R is -NH2or -NHOH; m1 is 0 or 1; m2 is 0 or 1; when m1 is 1 and m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m1 is 1 and m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; each RLis independently absent, –(C1-6alkyl)-, –(C1-6alkyl)-C(O)–, –C(O)–, –NH–C(O)–, or –NH–C(S)–; the linker is a linear or branched chain of n1 units of -Xaa11-, and / or –L1R1– and / or –(L1)2R1–, wherein: n1 is 1-20; each Xaa11is independently an amino acid; each R1is, independently, a linear, branched, and / or cyclic C1-20alkylenyl, alkenylenyl and / or alkynylenyl, wherein any carbon bonded to two other carbons is optionally independently replaced by N, S, or O, and carbons are optionally independently substituted with oxo, hydroxyl, sulfhydryl, -SeH, halogen, guanidino, amine, amide, urea, carboxylic acid, sulfonic acid, sulfinic acid, or phosphoric acid; L1bonds to carbon, wherein each L1is independently –S–, –N(R2)C(O)–,–C(O)N(R2)–, –NH–C(O)–NH–, –NH–C(S)–NH–, , , ,or ; and R2is H, methyl or ethyl; optionally, the linker comprises an albumin binder (Ralb), wherein the albumin binder is: -(CH2)n3-CH3wherein n3 is 8-20; -(CH2)n4-C(O)OH wherein n4 is 8-20;wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl;wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; orn6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated.

[0049] In some embodiments, the present disclosure relates to a peptidic compound of Formula (I), or a salt or solvate of Formula (I), Rradn6-[linker]-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-[ψ-Xaa9-(Xaa10)m2]m1-R (I) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; Xaa4is Ala, D-Ala, or Ser;Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; Xaa8is statine (Sta), Leu, D-Pro, Phe, cis-4-NHRa-D-Pro or cis-4-ORa-D-Pro, wherein Rais alkyl, cycloalkyl, or aryl; R is -NH2or -NHOH; m1 is 0 or 1; m2 is 0 or 1; when m1 is 1 and m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m1 is 1 and m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, Me2Thz (5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; the linker is a linear or branched chain of n1 units of -Xaa11-; n1 is 1-20; each Xaa11is independently an amino acid; optionally, the linker comprises an albumin binder (Ralb), wherein the albumin binder is: -(CH2)n3-CH3wherein n3 is 8-20; -(CH2)n4-C(O)OH wherein n4 is 8-20;wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl;wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; orn6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated.

[0050] In some embodiments of the compound of formula (A) or (I), or a salt or solvate of formula (A) or (I): (i) Xaa3is αMe-Trp, provided that the compound is not AMTG, AMTG2, and / or LW01186; (ii) Xaa7is Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); (iii) Xaa2is Gly, Arg, Asp, Glu, citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), or 2-amino-4-guanidinobutyric acid (Agb); (iv) m2 is 1; (v) at least one Rradis CROWN, CROWNGA, TCMC, PSC, a prosthetic group containing a trifluoroborate, an aryl or heteroaryl substituted with at least one radiohalogen, or an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; (vi) m1 is 0; or (vii) any combinations of (i)-(vi).

[0051] In some embodiments of the compound of formula (A) or (I), or a salt or solvate offormula (A) or (I), at least one Rradis CROWN, CROWNGA, TCMC, PSC, a prosthetic group containing a trifluoroborate, an aryl or heteroaryl substituted with at least one radiohalogen, or an aryl or heteroaryl substituted with at least one fluorine precursor leaving group. In some embodiments of the compound of formula (A) or (I), or a salt or solvate of formula (A) or (I), at least one Rradis CROWN, TCMC, PSC, a prosthetic group containing a trifluoroborate, an aryl or heteroaryl substituted with at least one radiohalogen, or an aryl or heteroaryl substituted with at least one fluorine precursor leaving group.

[0052] In some embodiments, Xaa1being an N-terminal amino acid residue D-Phe indicates Xaa1having the structure where * indicates the connectivity to the –[linker]-or to the –[linker]-RL- and ** indicates the connectivity to Xaa2. In embodiments, similar configuration is understood with other Xaa1amino acids.

[0053] In some embodiments of the compound of formula (A) or (I), or salt or solvate of formula (A) or (I), each Xaa11is independently selected from any proteinogenic amino acid or nonproteinogenic amino acid disclosed in Table A.

[0054] In some embodiments, the present disclosure relates to a peptidic compound of Formula (IA), or a salt or solvate of Formula (IA), Rradn6-[linker]-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-[ψ-Xaa9-(Xaa10)m2]m1-R (IA) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is αMe-Trp; Xaa4is Ala, D-Ala, or Ser; Xaa5is Val or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala);Xaa8is statine (Sta), Leu, D-Pro, Phe, cis-4-NHRa-D-Pro or cis-4-ORa-D-Pro, wherein Rais alkyl, cycloalkyl, or aryl; R is -NH2or -NHOH; m1 is 0 or 1; when m1 is 1 and m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, or Leu, wherein Rais alkyl, cycloalkyl, or aryl; when m1 is 1 and m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; RLis absent, –(C1-6alkyl)-, –(C1-6alkyl)-C(O)–, –C(O)–, –NH–C(O)–, or –NH–C(S)–; the linker is a linear or branched chain of n1 units of -Xaa11-: n1 is 1-20; each Xaa11is independently an amino acid; optionally, the linker is bonded to an albumin binder (Ralb), wherein Ralbis: -(CH2)n3-CH3wherein n3 is 8-20; -(CH2)n4-C(O)OH wherein n4 is 8-20;wherein n2 is 1-5, n5 is 1-4, each R3ais independently H or methyl, and each R3bis independently I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; wherein n2 is 1-5, n5 is 1-4, each R3aisindependently H or methyl, and each R3bis independently I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; orn6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator;an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; wherein when Xaa5is Val, RLis absent, and the linker is 4-amino-(1-carboxymethyl)piperidine (Pip), then Rradis not DOTA or DOTAGA; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated.

[0055] In some embodiments of the compounds of Formula (A), (I) or (IA), the linker and RLtogether form a p-aminomethylaniline-diglycolic acid (pABzA-DIG) linker, a 4-amino-(1-carboxymethyl)piperidine (Pip) linker, a 9-amino-4,7-dioxanonanoic acid (dPEG2) linker, or a 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp) linker.

[0056] In some embodiments, the present disclosure relates to a peptidic compound of Formula (IA-1), or a salt or solvate of Formula (IA-1), Rrad-[linker]-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-ψ-Xaa9-(Xaa10)m2-R (SEQ ID NO: 2) (IA-1) wherein: Xaa1is an N-terminal amino acid residue of D-Phe; Xaa2is Gln; Xaa3is αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly; Xaa7is His; Xaa8is Sta or Leu; R is -NH2or -NHOH; when m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro or Leu; when m2 is 1, Xaa9is Pro or Leu; and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val or Tle; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; the linker is, wherein * indicates the connectivity to Rrad; Rradis a radiometal chelator; wherein when Xaa5is Val, then Rradis not DOTA or DOTAGA; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated.

[0057] In some embodiments, the present disclosure relates to a peptidic compound of Formula (IB), or a salt or solvate of Formula (IB), Rradn6-[linker]-RL-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-[ψ-Xaa9-(Xaa10)m2]m1-R (IB) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is statine (Sta), Leu, D-Pro, Phe, cis-4-NHRa-D-Pro or cis-4-ORa-D-Pro, wherein Rais alkyl, cycloalkyl, or aryl R is -NH2or -NHOH; m1 is 0 or 1;m2 is 0 or 1; when m1 is 1 and m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz); when m1 is 1 and m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; RLis absent, –C(O)–, –NH–C(O)–, or –NH–C(S)–; the linker is a linear or branched chain of n1 units of -Xaa11-, and / or –L1R1– and / or –(L1)2R1–, wherein: n1 is 1-20; each Xaa11is independently an amino acid; each R1is, independently, a linear, branched, and / or cyclic C1-20alkylenyl, C2-20alkenylenyl and / or C2-20alkynylenyl, wherein any carbon bonded to two other carbons is optionally independently replaced by N, S, or O, and carbons are optionally independently substituted with oxo, hydroxyl, sulfhydryl, -SeH, halogen, guanidino, amine, amide, urea, carboxylic acid, sulfonic acid, sulfinic acid, or phosphoric acid; L1bonds to carbon, wherein each L1is independently –S–, –N(R2)C(O)–,–C(O)N(R2)–, –NH–C(O)–NH–, –NH–C(S)–NH–, , , ,or ; andR2is H, methyl or ethyl; optionally, the linker is bonded to an albumin binder (Ralb), wherein Ralbis: -(CH2)n3-CH3wherein n3 is 8-20; -(CH2)n4-C(O)OH wherein n4 is 8-20; wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl;wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, andR3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; orn6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated.

[0058] In some embodiments, the present disclosure relates to a peptidic compound of Formula (IB-1), or a salt or solvate of Formula (IB-1), Rrad-[linker]-RL-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-ψ-Xaa9-(Xaa10)m2-R (IB-1) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala;Xaa7is Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is statine (Sta), Leu, D-Pro, or Phe; R is -NH2or -NHOH; m2 is 0 or 1; when m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, Me2Thz (5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; the linker and RLtogether form a p-aminomethylaniline-diglycolic acid (pABzA-DIG) linker, a 4-amino-(1-carboxymethyl)piperidine (Pip) linker, a 9-amino-4,7-dioxanonanoic acid (dPEG2) linker, or a 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp) linker; Rradis a radiometal chelator; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated.

[0059] In some embodiments of the compounds of formula (IB) or (IB-1), Xaa7is Trp, Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), 3-Quin-Ala, or 2-Quin-Ala. In some embodiments, Xaa7is Trp, Trp(5-F), or 3-Quin-Ala.

[0060] In some embodiments of the compounds of formula (IB) or (IB-1), Xaa1is an N-terminal amino acid residue D-Phe. In some embodiments, Xaa2is Gln or Cit. In some embodiments, Xaa2is Gln. In some embodiments, Xaa3is Trp or αMe-Trp. In some embodiments, Xaa4is Ala. In some embodiments, Xaa5is Val or Tle. In some embodiments, Xaa6is Gly or NMe-Gly. In some embodiments, Xaa8is Sta or Leu. In some embodiments, m2 is 0 and Xaa9-R is a C-terminally amidated (R is -NH2) amino acid residue Pro or Leu. In some embodiments, m2 is 1 and Xaa9is Pro or Leu.

[0061] In some embodiments of the compounds of formula (IB) or (IB-1), Xaa1is an N-terminal amino acid residue D-Phe and Xaa2is Gln or Cit. In some embodiments, Xaa1is anN-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; and Xaa3is Trp or αMe-Trp. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; and Xaa4is Ala. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; and Xaa5is Val or Tle. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; and Xaa6is Gly or NMe-Gly. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; and Xaa8is Sta or Leu. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; Xaa7is Trp, Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), 3-Quin-Ala, or 2-Quin-Ala; and Xaa8is Sta or Leu. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; Xaa7is Trp, Trp(5-F), or 3-Quin-Ala; and Xaa8is Sta or Leu.

[0062] In some embodiments, the present disclosure relates to a peptidic compound of Formula (I), or a salt or solvate of Formula (I): Rradn6-[linker]-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-[ψ-Xaa9-(Xaa10)m2]m1-R (I) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, D-Cpa, D-Nal, or D-2-Nal; Xaa2is Asp, Asn, Gln, or Glu; Xaa3is Trp, Trp(Me), αMe-Trp, Trp(7-F), Trp(6-F), Trp(5-F), or Trp(4-F); Xaa4is Ala or D-Ala; Xaa5is Val or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), or αMe-Trp; Xaa8is Leu; m1 is 1 and m2 is 0; Xaa9is Pro, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), or 4,4-difluoroproline (difluoroPro); R is -NH2; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; the linker comprises p-aminomethylaniline-diglycolic acid (pABzA-DIG),4-amino-(1-carboxymethyl)piperidine (Pip, 9-amino-4,7-dioxanonanoic acid(dPEG2), or 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp), wherein the linker optionally comprises an albumin binder; n6 is 1; Rradis a radiometal chelator; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, or Xaa9is each optionally N-methylated.

[0063] In some embodiments, the compound is selected from the group consisting of: (Compound 6; SEQ ID NO: 26), (Compound 6A; SEQ ID NO: 27), (Compound 8; SEQ ID NO: 30),(Compound 10A; SEQ ID NO: 33), or a salt or solvate thereof. In some embodiments, the compound is conjugated by a radiometal. In some embodiments, the radiometal is68Ga,177Lu, or225Ac.

[0064] In some embodiments, the present disclosure relates to a peptidic compound of Formula (IC), or a salt or solvate of Formula (IC), Rradn6-[linker]-RL-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-[ψ-Xaa9-(Xaa10)m2]m1-R (IC) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Glu, citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), or 2-amino-4-guanidinobutyric acid (Agb); Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is statine (Sta), Leu, D-Pro, Phe, cis-4-NHRa-D-Pro or cis-4-ORa-D-Pro, wherein Rais alkyl, cycloalkyl, or aryl; R is -NH2or -NHOH;m1 is 0 or 1; m2 is 0 or 1; when m1 is 1 and m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m1 is 1 and m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; RLis –C(O)–, –NH–C(O)–, or –NH–C(S)–; the linker is a linear or branched chain of n1 units of -Xaa11-, and / or –L1R1– and / or –(L1)2R1–, wherein: n1 is 1-20; each Xaa11is independently an amino acid; each R1is, independently, a linear, branched, and / or cyclic C1-20alkylenyl, C2-20alkenylenyl and / or C2-20alkynylenyl, wherein any carbon bonded to two other carbons is optionally independently replaced by N, S, or O, and carbons are optionally independently substituted with oxo, hydroxyl, sulfhydryl, -SeH, halogen, guanidino, amine, amide, urea, carboxylic acid, sulfonic acid, sulfinic acid, or phosphoric acid; L1bonds to carbon, wherein each L1is independently –S–, –N(R2)C(O)–,–C(O)N(R2)–, –NH–C(O)–NH–, –NH–C(S)–NH–, , , ,or ; andR2is H, methyl or ethyl; optionally, the linker is bonded to an albumin binder (Ralb), wherein Ralbis: -(CH2)n3-CH3wherein n3 is 8-20; -(CH2)n4-C(O)OH wherein n4 is 8-20;wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl;wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; or ; n6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated.

[0065] In some embodiments, the present disclosure relates to a peptidic compound of Formula (IC-1), or a salt or solvate of Formula (IC-1), Rrad-[linker]-RL-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-ψ-Xaa9-(Xaa10)m2-R (IC-1) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Glu, citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), or 2-amino-4-guanidinobutyric acid (Agb); Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala;Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is statine (Sta), Leu, D-Pro, or Phe; R is -NH2or -NHOH; m2 is 0 or 1; when m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; the linker and RLtogether form a p-aminomethylaniline-diglycolic acid (pABzA-DIG) linker, a 4-amino-(1-carboxymethyl)piperidine (Pip) linker, a 9-amino-4,7-dioxanonanoic acid (dPEG2) linker, or a 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp) linker; Rradis a radiometal chelator; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated.

[0066] In some embodiments of the compounds of formula (IC) or (IC-1), Xaa2is Cit, Glu, or Agb. In some embodiments, Xaa2is Cit.

[0067] In some embodiments of the compounds of formula (IC) or (IC-1), Xaa1is an N-terminal amino acid residue D-Phe. In some embodiments, Xaa3is Trp or αMe-Trp. In some embodiments, Xaa4is Ala. In some embodiments, Xaa5is Val or Tle. In some embodiments, Xaa6is Gly or NMe-Gly. In some embodiments, Xaa7is His, Trp, Trp(5-F), 3-Quin-Ala, or 2-Quin-Ala. In some embodiments, Xaa8is Sta or Leu. In some embodiments, m2 is 0 and Xaa9-R is a C-terminally amidated (R is -NH2) amino acid residue Pro or Leu. In some embodiments, m2 is 1 and Xaa9is Pro or Leu.

[0068] In some embodiments of the compounds of formula (IC) or (IC-1), Xaa1is an N-terminal amino acid residue D-Phe and Xaa3is Trp or αMe-Trp. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa3is Trp or αMe-Trp; and Xaa4is Ala. Insome embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa3is Trp or αMe-Trp; Xaa4is Ala; and Xaa5is Val or Tle. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; and Xaa6is Gly or NMe-Gly. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; and Xaa7is His, Trp, Trp(5-F), 3-Quin-Ala, or 2-Quin-Ala. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; Xaa7is His, Trp, Trp(5-F), 3-Quin-Ala, or 2-Quin-Ala; and Xaa8is Sta or Leu. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; Xaa7is His, Trp, Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), 3-Quin-Ala, or 2-Quin-Ala; and Xaa8is Sta or Leu. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; Xaa7is His, Trp, Trp(5-F), or 3-Quin-Ala; and Xaa8is Sta or Leu. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Cit, Glu, or Agb; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; Xaa7is His, Trp, Trp(5-F), or 3-Quin-Ala; and Xaa8is Sta or Leu. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; Xaa7is His, Trp, Trp(5-F), or 3-Quin-Ala; and Xaa8is Sta or Leu.

[0069] In some embodiments, the present disclosure relates to a peptidic compound of Formula (ID), or a salt or solvate of Formula (ID), Rradn6-[linker]-RL-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-ψ-Xaa9-(Xaa10)m2-R (ID) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine,L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is statine (Sta), Leu, D-Pro, or Phe; Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz); R is -NH2or -NHOH; m2 is 1; Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; RLis –C(O)–, –NH–C(O)–, or –NH–C(S)–; the linker is a linear or branched chain of n1 units of -Xaa11-, and / or –L1R1– and / or –(L1)2R1–, wherein: n1 is 1-20; each Xaa11is independently an amino acid; each R1is, independently, a linear, branched, and / or cyclic C1-20alkylenyl, C2-20alkenylenyl and / or C2-20alkynylenyl, wherein any carbon bonded to two other carbons is optionally independently replaced by N, S, or O, and carbons are optionally independently substituted with oxo, hydroxyl, sulfhydryl, -SeH, halogen, guanidino, amine, amide, urea, carboxylic acid, sulfonic acid, sulfinic acid, or phosphoric acid; L1bonds to carbon, wherein each L1is independently –S–, –N(R2)C(O)–,–C(O)N(R2)–, –NH–C(O)–NH–, –NH–C(S)–NH–, , , ,or ; andR2is H, methyl or ethyl; optionally, the linker is bonded to an albumin binder (Ralb), wherein Ralbis: -(CH2)n3-CH3wherein n3 is 8-20; -(CH2)n4-C(O)OH wherein n4 is 8-20;wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl;wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; orn6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated.

[0070] In some embodiments, the present disclosure relates to a peptidic compound of Formula (ID-1), or a salt or solvate of Formula (ID-1), Rrad-[linker]-RL-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-ψ-Xaa9-(Xaa10)m2-R (ID-1) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala);Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is statine (Sta), Leu, D-Pro, or Phe; Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz); R is -NH2or -NHOH; m2 is 1; Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; the linker and RLtogether form a p-aminomethylaniline-diglycolic acid (pABzA-DIG) linker, a 4-amino-(1-carboxymethyl)piperidine (Pip) linker, a 9-amino-4,7-dioxanonanoic acid (dPEG2) linker, or a 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp) linker; Rradis a radiometal chelator; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated.

[0071] In some embodiments of the compounds of formula (ID) or (ID-1), Xaa1is an N-terminal amino acid residue D-Phe. In some embodiments, Xaa2is Gln or Cit. In some embodiments, Xaa3is Trp or αMe-Trp. In some embodiments, Xaa4is Ala. In some embodiments, Xaa5is Val or Tle. In some embodiments, Xaa6is Gly or NMe-Gly. In some embodiments, Xaa7is His, Trp, Trp(5-F), 3-Quin-Ala, or 2-Quin-Ala. In some embodiments, Xaa8is Sta or Leu. In some embodiments, Xaa9is Pro or Leu. In some embodiments, Xaa10is Val or Tle.

[0072] In some embodiments of the compounds of formula (ID) or (ID-1), Xaa1is an N-terminal amino acid residue D-Phe and Xaa2is Gln or Cit. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; and Xaa3is Trp or αMe-Trp. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; ad Xaa3is Trp or αMe-Trp; and Xaa4is Ala. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; and Xaa5is Val or Tle.In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; and Xaa6is Gly or NMe-Gly. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; and Xaa7is His, Trp, Trp(5-F), 3-Quin-Ala, or 2-Quin-Ala. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; Xaa7is His, Trp, Trp(5-F), 3-Quin-Ala, or 2-Quin-Ala; and Xaa8is Sta or Leu. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; Xaa7is His, Trp(5-F), or 3-Quin-Ala; and Xaa8is Sta or Leu. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; Xaa7is His, Trp, Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), 3-Quin-Ala, or 2-Quin-Ala; and Xaa8is Sta or Leu. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; Xaa7is His, Trp, Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), 3-Quin-Ala, or 2-Quin-Ala; Xaa8is Sta or Leu; and Xaa9is Pro or Leu. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; Xaa7is His, Trp(5-F), or 3-Quin-Ala; and Xaa8is Sta or Leu. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; Xaa7is His, Trp(5-F), or 3-Quin-Ala; Xaa8is Sta or Leu; and Xaa9is Pro or Leu.

[0073] In some embodiments, the present disclosure relates to a peptidic compound of Formula (IE), or a salt or solvate of Formula (IE), Rradn6-RL-[linker]-RL-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-[ψ-Xaa9-(Xaa10)m2]m1-R (IE) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or3-quinoylalanine (3-Quin-Ala); Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is statine (Sta), Leu, D-Pro, Phe, cis-4-NHRa-D-Pro or cis-4-ORa-D-Pro, wherein Rais alkyl, cycloalkyl, or aryl; R is -NH2or -NHOH; m1 is 0 or 1; m2 is 0 or 1; when m1 is 1 and m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m1 is 1 and m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; each RLis independently absent, –(C1-6alkyl)-, –(C1-6alkyl)-C(O)–, –C(O)–, –NH–C(O)–, or –NH–C(S)–; the linker is a linear or branched chain of n1 units of -Xaa11-, and / or –L1R1– and / or –(L1)2R1–, wherein: n1 is 1-20; each Xaa11is independently an amino acid; each R1is, independently, a linear, branched, and / or cyclic C1-20alkylenyl, alkenylenyl and / or alkynylenyl, wherein any carbon bonded to two other carbons is optionally independently replaced by N, S, or O, and carbons are optionally independently substituted with oxo, hydroxyl, sulfhydryl, -SeH, halogen, guanidino, amine, amide, urea, carboxylic acid, sulfonic acid, sulfinic acid, or phosphoric acid;L1bonds to carbon, wherein each L1is independently –S–, –N(R2)C(O)–,–C(O)N(R2)–, –NH–C(O)–NH–, –NH–C(S)–NH–, , , ,or ; and R2is H, methyl or ethyl; optionally, the linker comprises an albumin binder (Ralb), wherein the albumin binder is: -(CH2)n3-CH3wherein n3 is 8-20; -(CH2)n4-C(O)OH wherein n4 is 8-20; wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; or ; n6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; wherein at least one Rradis CROWN, CROWNGA, TCMC, PSC, a prosthetic group containing a trifluoroborate, an aryl or heteroaryl substituted with at least one radiohalogen, or an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated.

[0074] In some embodiments, of a compound of Formula (IE), or a salt or solvate of Formula (IE), at least one Rradis CROWN, TCMC, PSC, a prosthetic group containing a trifluoroborate, an aryl or heteroaryl substituted with at least one radiohalogen, or an aryl or heteroaryl substituted with at least one fluorine precursor leaving group.

[0075] In some embodiments, the present disclosure relates to a peptidic compound of Formula (IE-1), or a salt or solvate of Formula (IE-1), Rrad-RL-[linker]-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-ψ-Xaa9-(Xaa10)m2-R (IE-1) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is statine (Sta), Leu, D-Pro, or Phe R is -NH2or -NHOH; m2 is 0 or 1; when m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val,Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; RLis independently absent, –(C1-3alkyl)-, –(C1-3alkyl)-C(O)–, –C(O)–, –NH–C(O)–, or –NH–C(S)–; the linker is a linear or branched chain of n1 units of -Xaa11-, and / or –L1R1– and / or –(L1)2R1–, wherein: n1 is 1-6; each Xaa11is independently an amino acid; each R1is, independently, a linear, branched, and / or cyclic C1-6alkylenyl, C2-6alkenylenyl and / or C2-6alkynylenyl, wherein any carbon bonded to two other carbons is optionally independently replaced by N, S, or O, and carbons are optionally independently substituted with oxo, hydroxyl, sulfhydryl, -SeH, halogen, guanidino, amine, amide, urea, carboxylic acid, sulfonic acid, sulfinic acid, or phosphoric acid; L1bonds to carbon, wherein each L1is independently –S–, –N(R2)C(O)–,–C(O)N(R2)–, –NH–C(O)–NH–, –NH–C(S)–NH–, , , ,or ; and R2is H, methyl or ethyl; Rradis CROWN, CROWNGA, TCMC, PSC, a prosthetic group containing a trifluoroborate, an aryl or heteroaryl substituted with at least one radiohalogen, or an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated.

[0076] In some embodiments, a compound of Formula (IE-1), or a salt or solvate of Formula (IE-1), at least one Rradis CROWN, TCMC, PSC, a prosthetic group containing a trifluoroborate, an aryl or heteroaryl substituted with at least one radiohalogen, or an aryl or heteroaryl substituted with at least one fluorine precursor leaving group.

[0077] In some embodiments of the compounds of formula (IE) or (IE-1), the linker is -Xaa11-. In some embodiments, the linker is -Xaa11- and RLis absent. In some embodiments, the linker is Pip and RLis absent. In some embodiments, the linker is -Xaa11- and RLis –(C1-3alkyl)-, –(C1-3alkyl)-C(O)–, or –C(O)–. In some embodiments, the linker is -Xaa11- and RLis –C(O)–. In some embodiments, the linker is Pip and RLis –C(O)–.

[0078] In some embodiments of the compounds of formula (IE) or (IE-1), the linker is a linear or branched chain of n1 units of -Xaa11- and / or –L1R1–. In some embodiments, n1 is 1-3. In some embodiments, n1 is 1 or 2.

[0079] In some embodiments of the compounds of formula (IE) or (IE-1), the linker is -Xaa11-–R1L1–. In some embodiments, the linker is *-Xaa11–R1L1–, where * indicates the connectivity to Xaa1. In some embodiments, the linker is *-Xaa11–C(O)CH2–L1–, where * indicates the connectivity to Xaa1. In some embodiments, the linker is *-Xaa11–C(O)CH2–L1–, where * indicates the connectivity to Xaa1 and L1 is , or . In some embodiments, RLis –(C1-3alkyl)–, –(C1-3alkyl)-C(O)–, or –C(O)–. In some embodiments, RLis –(C1-3alkyl)–. In some embodiments, RLis –CH2–. In some embodiments, RLis absent.

[0080] In some embodiments of the compounds of formula (IE) or (IE-1), Xaa1is an N-terminal amino acid residue D-Phe. In some embodiments, Xaa2is Gln or Cit. In some embodiments, Xaa3is Trp or αMe-Trp. In some embodiments, Xaa4is Ala. In some embodiments, Xaa5is Val or Tle. In some embodiments, Xaa6is Gly or NMe-Gly. In some embodiments, Xaa7is His, Trp, Trp(5-F), 3-Quin-Ala, or 2-Quin-Ala. In some embodiments, Xaa8is Sta or Leu. In some embodiments, m2 is 0 and Xaa9-R is a C-terminally amidated (R is -NH2) amino acid residue Pro or Leu. In some embodiments, m2 is 1 and Xaa9is Pro or Leu.

[0081] In some embodiments of the compounds of formula (IE) or (IE-1), Xaa1is an N-terminal amino acid residue D-Phe and Xaa2is Gln or Cit. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; and Xaa3is Trp or αMe-Trp. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; ad Xaa3is Trp or αMe-Trp; and Xaa4is Ala. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; and Xaa5is Val or Tle. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; and Xaa6is Gly or NMe-Gly. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; and Xaa7is His, Trp, Trp(5-F), 3-Quin-Ala, or 2-Quin-Ala. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; Xaa7is His, Trp, Trp(5-F), 3-Quin-Ala, or 2-Quin-Ala; and Xaa8is Sta or Leu. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; Xaa7is His, Trp, Trp(5-F), or 3-Quin-Ala; and Xaa8is Sta or Leu. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; Xaa7is His, Trp, Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), 3-Quin-Ala, or 2-Quin-Ala; and Xaa8is Sta or Leu. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; Xaa7is His, Trp, Trp(7-F), Trp(6-F), Trp(5-F),Trp(4-F), 3-Quin-Ala, or 2-Quin-Ala; Xaa8is Sta or Leu; and Xaa9is Pro or Leu. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; Xaa7is His, Trp, Trp(5-F), or 3-Quin-Ala; and Xaa8is Sta or Leu. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; Xaa7is His, Trp, Trp(5-F), or 3-Quin-Ala; Xaa8is Sta or Leu; and Xaa9is Pro or Leu.In some embodiments, the present disclosure relates to a peptidic compound of Formula (IF), or a salt or solvate of Formula (IF), Rradn6-RL-[linker]-RL-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8--R (IF) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(5-OH), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; R is -NH2or -NHOH; Xaa8-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from statine (Sta), Leu, D-Pro, Phe, cis-4-NHRa-D-Pro or cis-4-ORa-D-Pro, wherein Rais alkyl, cycloalkyl, or aryl; each RLis independently absent, –(C1-6alkyl)-, –(C1-6alkyl)-C(O)–, –C(O)–, –NH–C(O)–, or –NH–C(S)–; the linker is a linear or branched chain of n1 units of -Xaa11-, and / or –L1R1– and / or–(L1)2R1–, wherein: n1 is 1-20; each Xaa11is independently an amino acid; each R1is, independently, a linear, branched, and / or cyclic C1-20alkylenyl, alkenylenyl and / or alkynylenyl, wherein any carbon bonded to two other carbons is optionally independently replaced by N, S, or O, and carbons are optionally independently substituted with oxo, hydroxyl, sulfhydryl, -SeH, halogen, guanidino, amine, amide, urea, carboxylic acid, sulfonic acid, sulfinic acid, or phosphoric acid; L1bonds to carbon, wherein each L1is independently –S–, –N(R2)C(O)–,–C(O)N(R2)–, –NH–C(O)–NH–, –NH–C(S)–NH–, , , ,or ; and R2is H, methyl or ethyl; optionally, the linker comprises an albumin binder (Ralb), wherein the albumin binder is: -(CH2)n3-CH3wherein n3 is 8-20; -(CH2)n4-C(O)OH wherein n4 is 8-20; wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; or ; n6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, or Xaa8is each optionallymethylated.

[0082] In some embodiments, the present disclosure relates to a peptidic compound of Formula (IF-1), or a salt or solvate of Formula (IF-1), Rrad-RL-[linker]-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8--R (IF-1) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(5-OH), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; R is -NH2or -NHOH; Xaa8-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from is statine (Sta), Leu, D-Pro, Phe, cis-4-NHRa-D-Pro or cis-4-ORa-D-Pro, wherein Rais alkyl, cycloalkyl, or aryl; the linker and RLtogether form a p-aminomethylaniline-diglycolic acid (pABzA-DIG) linker, a 4-amino-(1-carboxymethyl)piperidine (Pip) linker, a 9-amino-4,7-dioxanonanoic acid (dPEG2) linker, or a 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp) linker; Rradis a radiometal chelator; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, or Xaa8, is each optionally N-methylated.

[0083] In some embodiments of the compounds of formula (IF) or (IF-1), Xaa8-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) aminoacid residue selected from D-Pro, cis-4-NHRa-D-Pro or cis-4-ORa-D-Pro, wherein Rais alkyl, cycloalkyl, or aryl. In some embodiments, Rais C1-C6alkyl, C3-C7cycloalkyl, or phenyl. In some embodiments, Rais C3-C7cycloalkyl. In some embodiments, Rais C6cycloalkyl.

[0084] In some embodiments of the compounds of formula (IF) or (IF-1), Xaa8-R is a C-terminally amidated (R is -NH2) amino acid residue selected from cis-4-cyclohexyloxy-D-Pro or cis-4-cyclohexylamino-D-Pro.

[0085] In some embodiments of the compounds of formula (IF) or (IF-1), Xaa1is an N-terminal amino acid residue D-Phe. In some embodiments, Xaa2is Gln or Cit. In some embodiments, Xaa3is Trp or αMe-Trp. In some embodiments, Xaa4is Ala. In some embodiments, Xaa5is Val or Tle. In some embodiments, Xaa6is Gly or NMe-Gly. In some embodiments, Xaa7is His, Trp, Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), 3-Quin-Ala, or 2-Quin-Ala. In some embodiments, Xaa7is His, Trp, Trp(5-F), or 3-Quin-Ala.

[0086] In some embodiments of the compounds of formula (IF) or (IF-1), Xaa1is an N-terminal amino acid residue D-Phe and Xaa2is Gln or Cit. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; and Xaa3is Trp or αMe-Trp. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; and Xaa4is Ala. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; and Xaa5is Val or Tle. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; and Xaa6is Gly or NMe-Gly. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; and Xaa7is His, Trp, Trp(5-F), or 3-Quin-Ala. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; Xaa7is His, Trp, Trp(5-F), or 3-Quin-Ala; and Xaa8-R is a C-terminally amidated (R is -NH2) amino acid residue selected from cis-4-cyclohexyloxy-D-Pro or cis-4-cyclohexylamino-D-Pro.

[0087] In some embodiments, the present disclosure relates to a peptidic compound of Formula (II), or a salt or solvate of Formula (II), Rradn6-[linker]-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-[ψ-Xaa9-(Xaa10)m2]m1-R (II) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His;Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is statine (Sta), Leu, D-Pro, Phe, cis-4-NHRa-D-Pro or cis-4-ORa-D-Pro, wherein Rais alkyl, cycloalkyl, or aryl; R is -NH2or -NHOH; m1 is 0 or 1; m2 is 0 or 1; when m1 is 1 and m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m1 is 1 and m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; the linker is a linear or branched chain of n1 units of -Xaa11-, wherein at least one Xaa11is bonded to albumin binder (Ralb); n1 is 1-20; each Xaa11is independently an amino acid; Ralbis: -(CH2)n3-CH3wherein n3 is 8-20;-(CH2)n4-C(O)OH wherein n4 is 8-20; wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; or ; n6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, or Xaa10is each optionally methylated.

[0088] In some embodiments of the compounds of formula (II) the linker is a linear peptide of 3 to 6 amino acid residues, –Xaa11A–Xaa11B–(Xaa11C)1˗4–, wherein Xaa11A, Xaa11B, and Xaa11Care each independently an amino acid and wherein the radiolabeling group and the albumin-binding group are bonded to the free N-terminus of Xaa11Aand the side chain of Xaa11B, respectively, or are bonded to the side chain of Xaa11Band the free N-terminus of Xaa11A, respectively. In some embodiments, Xaa11Ais Gly, Glu, D-Glu, Asp, D-Asp, 2˗Aad, D-2-Aad, 3-Aad, or D-3-Aad. In some embodiments, Xaa11Ais Gly, Glu or D-Glu. In some embodiments, Xaa11Ais Gly. In some embodiments, Xaa11Bis Lys, Orn, D-Orn, Dab, D-Dab, Dap or D-Dap, any of which can form an amide bond with a carboxylate of a radiolabeling group or an albumin binding group. In some embodiments, Xaa11Bis Lys or D-Lys. In some such embodiments, (Xaa11C)1-4is diglycine. In some such embodiments, (Xaa11C)1-4is p-aminomethylaniline-diglycolic acid (pABzA-DIG), a 4-amino-(1-carboxymethyl)piperidine (Pip), a 9-amino-4,7-dioxanonanoic acid (dPEG2), or a 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp). In some such embodiments, (Xaa11C)1-4is Pip. In some embodiments, the C-terminus of Xaa11Cand the N-terminus of Xaa1arebonded.

[0089] In some embodiments of the compounds of formula (II) the linker is a branched peptide of 3 to 6 amino acid residues, –Xaa11B(Xaa11A)–(Xaa11C)1-4–, wherein Xaa11A, Xaa11B, and Xaa11Care each independently an amino acid and wherein the C-terminus of Xaa11Aforms an amide with the side chain of Xaa11B, and wherein the radiolabeling group and the albumin-binding group are bonded to the free N-termini of Xaa11Aand Xaa11B, respectively, or are bonded to the free N-termini of Xaa11Band Xaa11A, respectively. In some embodiments, Xaa11Ais Gly, Glu, D-Glu, Asp, D-Asp, 2˗Aad, D-2-Aad, 3-Aad, or D-3-Aad. In some embodiments, Xaa11Ais Glu or D-Glu. In some embodiments, Xaa11Bis Lys, D-Lys, Orn, D-Orn, Dab, D-Dab, Dap or D-Dap. In some embodiments, Xaa11Bis Lys or D-Lys. In some such embodiments, (Xaa11C)1-4is diglycine. In some such embodiments, (Xaa11C)1-4is p-aminomethylaniline-diglycolic acid (pABzA-DIG), a 4-amino-(1-carboxymethyl)piperidine (Pip), a 9-amino-4,7-dioxanonanoic acid (dPEG2), or a 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp). In some such embodiments, (Xaa11C)1-4is Pip. In some embodiments, the C-terminus of Xaa11Cand the N-terminus of Xaa1are bonded.

[0090] In some embodiments, the present disclosure relates to a peptidic compound of Formula (IIA), or a salt or solvate of Formula (IIA), Rrad-[linker]-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-ψ-Xaa9-(Xaa10)m2-R (IIA) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me),Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is statine (Sta), Leu, D-Pro, or Phe; R is -NH2or -NHOH; m2 is 0 or 1; when m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, Me2Thz (5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, Me2Thz (5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; the linker is: a linear peptide of 3 to 6 amino acid residues, –Xaa11A–Xaa11B–(Xaa11C)1˗4–, wherein Xaa11A, Xaa11B, and Xaa11Care each independently an amino acid and wherein the radiolabeling group and the albumin-binding group are bonded to the free N-terminus of Xaa11Aand the side chain of Xaa11B, respectively, or are bonded to the side chain of Xaa11Band the free N-terminus of Xaa11A, respectively; or a branched peptide of 3 to 6 amino acid residues, –Xaa11B(Xaa11A)–(Xaa11C)1-4–, wherein Xaa11A, Xaa11B, and Xaa11Care each independently an amino acid and wherein the C-terminus of Xaa11Aforms an amide with the side chain of Xaa11B, and wherein the radiolabeling group and the albumin-binding group are bonded to the free N-termini of Xaa11Aand Xaa11B, respectively, or are bonded to the free N-termini of Xaa11Band Xaa11A, respectively; Ralbisn2 is 1-5; n5 is 1-4; each R3ais independently H or methyl; each R3bis independently I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl;Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, or Xaa10is each optionally methylated.

[0091] In some embodiments of the compounds of formula (II) or (IIA), n2 is 1. In some embodiments, Ralbis . In some embodiments, Ralbis

[0092] In some embodiments of the compounds of formula (II) or (IIA) the linker is a linear peptide of 3 amino acid residues, –Xaa11A–Xaa11B–Xaa11C–, wherein Xaa11A, Xaa11B, and Xaa11Care each independently an amino acid and wherein the radiolabeling group and the albumin-binding group are bonded to the free N-terminus of Xaa11Aand the side chain of Xaa11B, respectively, or are bonded to the side chain of Xaa11Band the free N-terminus of Xaa11A, respectively. In some embodiments, Xaa11Ais Gly, Glu, D-Glu, Asp, D-Asp, 2˗Aad, D-2-Aad, 3-Aad, or D-3-Aad. In some embodiments, Xaa11Ais Gly, Glu or D-Glu. In some embodiments, Xaa11Ais Gly. In some embodiments, Xaa11Bis Lys, D-Lys, Orn, D-Orn, Dab, D-Dab, Dap or D-Dap, any of which can form an amide bond with a carboxylate of a radiolabeling group or an albumin binding group. In some embodiments, Xaa11Bis Lys or D-Lys. In some such embodiments, Xaa11Cis p-aminomethylaniline-diglycolic acid (pABzA-DIG), a 4-amino-(1-carboxymethyl)piperidine (Pip), a 9-amino-4,7-dioxanonanoic acid (dPEG2), or a 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp). In some such embodiments, Xaa11Cis Pip. In some embodiments, the C-terminus of Xaa11Cand the N-terminus of Xaa1are bonded.

[0093] In some embodiments of the compounds of formula (II) or (IIA) the linker is -Gly-Lys-Pip-. In some embodiments, the radiolabeling group is bonded to the free N-terminus of Xaa11Aand the albumin-binding group is bonded to the side chain of Xaa11B. In some embodiments, the radiolabeling group is bonded to the free N-terminus of Gly and the albumin-binding group is bonded to the side chain of Lys.

[0094] In some embodiments of the compounds of formula (II) or (IIA) the linker is a branched peptide of 3 amino acid residues, –Xaa11B(Xaa11A)–Xaa11C–, wherein Xaa11A, Xaa11B, andXaa11Care each independently an amino acid and wherein the C-terminus of Xaa11Aforms an amide with the side chain of Xaa11B, and wherein the radiolabeling group and the albumin-binding group are bonded to the free N-termini of Xaa11Aand Xaa11B, respectively, or are bonded to the free N-termini of Xaa11Band Xaa11A, respectively. In some embodiments, Xaa11Ais Gly, Glu, D-Glu, Asp, D-Asp, 2˗Aad, D-2-Aad, 3-Aad, or D-3-Aad. In some embodiments, Xaa11Ais Glu or D-Glu. In some embodiments, Xaa11Bis Lys, D-Lys, Orn, D-Orn, Dab, D-Dab, Dap or D-Dap. In some embodiments, Xaa11Bis Lys or D-Lys. In some such embodiments, Xaa11Cis p-aminomethylaniline-diglycolic acid (pABzA-DIG), a 4-amino-(1-carboxymethyl)piperidine (Pip), a 9-amino-4,7-dioxanonanoic acid (dPEG2), or a 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp). In some such embodiments, Xaa11Cis Pip. In some embodiments, the C-terminus of Xaa11Cand the N-terminus of Xaa1are bonded.

[0095] In some embodiments of the compounds of formula (II) or (IIA), Xaa1is an N-terminal amino acid residue D-Phe. In some embodiments, Xaa2is Gln or Cit. In some embodiments, Xaa2is Gln. In some embodiments, Xaa3is Trp or αMe-Trp. In some embodiments, Xaa4is Ala. In some embodiments, Xaa5is Val or Tle. In some embodiments, Xaa6is Gly or NMe-Gly. In some embodiments, Xaa7is His, Trp, Trp(7-F), Trp(6-F), Trp(5-F), or Trp(4-F). In some embodiments, Xaa8is Sta or Leu. In some embodiments, m2 is 0 and Xaa9-R is a C-terminally amidated (R is -NH2) amino acid residue Pro or Leu. In some embodiments, m2 is 1 and Xaa9is Pro or Leu.

[0096] In some embodiments of the compounds of formula (II) or (IIA), Xaa1is an N-terminal amino acid residue D-Phe and Xaa2is Gln or Cit. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; and Xaa3is Trp or αMe-Trp. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; and Xaa4is Ala. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; and Xaa5is Val or Tle. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; and Xaa6is Gly or NMe-Gly. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; and Xaa7is His, Trp, Trp(5-F), or 3-Quin-Ala. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; Xaa7is His, Trp, Trp(5-F), or 3-Quin-Ala; and Xaa8is Sta or Leu. In some embodiments, Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; Xaa7is His, Trp, Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), 3-Quin-Ala, or 2-Quin-Ala; and Xaa8is Sta or Leu.

[0097] In some embodiments, the present disclosure relates to a peptidic compound of Formula (B), or a salt or solvate of Formula (B), (B) wherein: each Xaa12is independently an N-terminal amino acid residue selected from p-aminomethylaniline-diglycolic acid (pABzA-DIG), 4-amino-(1-carboxymethyl)piperidine (Pip), 9-amino-4,7-dioxanonanoic acid (dPEG2), or 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp); each Xaa1is independently D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; each Xaa2is independently Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; each Xaa3is independently Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); each Xaa4is independently Ala, D-Ala, or Ser; each Xaa5is independently Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); each Xaa6is independently Gly or D-Ala; each Xaa7is independently His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); each Xaa8is independently statine (Sta), Leu, D-Pro, Phe, cis-4-NHRa-D-Pro or cis-4-ORa-D-Pro, wherein Rais alkyl, cycloalkyl, or aryl; each R is independently -NH2or -NHOH; each m1 is independently 0 or 1; each m2 is independently 0 or 1; when m1 is 1 and m2 is 0, each Xaa9-R is independently a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residueselected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m1 is 1 and m2 is 1, each Xaa9is independently Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; Xaa13is an amino acid with a sidechain comprising a carboxylic acid, wherein one Xaa12is bonded to the C-terminus of Xaa13and the other Xaa12is bonded to the sidechain of Xaa13; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; RLis absent, –(C1-6alkyl)-, –(C1-6alkyl)-C(O)–, –C(O)–, –NH–C(O)–, or –NH–C(S)–; L is a linker and the linker absent or is a linear or branched chain of n1 units of -Xaa11-, and / or –L1R1– and / or –(L1)2R1–, wherein: n1 is 1-20; each Xaa11is independently an amino acid; each R1is, independently, a linear, branched, and / or cyclic C1-20alkylenyl, alkenylenyl and / or alkynylenyl, wherein any carbon bonded to two other carbons is optionally independently replaced by N, S, or O, and carbons are optionally independently substituted with oxo, hydroxyl, sulfhydryl, -SeH, halogen, guanidino, amine, amide, urea, carboxylic acid, sulfonic acid, sulfinic acid, or phosphoric acid; L1bonds to carbon, wherein each L1is independently –S–, –N(R2)C(O)–,–C(O)N(R2)–, –NH–C(O)–NH–, –NH–C(S)–NH–, , , ,or ; and R2is H, methyl or ethyl; optionally, the linker comprises an albumin binder (Ralb), wherein the albumin binder is: -(CH2)n3-CH3wherein n3 is 8-20; -(CH2)n4-C(O)OH wherein n4 is 8-20; wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl;wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; or n6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated.

[0098] In some embodiments, the present disclosure relates to a peptidic compound of Formula (B-1), or a salt or solvate of formula (B-1), Rrad-[linker]-Xaa13-[Xaa12-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-ψ-Xaa9-(Xaa10)m2-R]2(B-1) wherein: Xaa12is an N-terminal amino acid residue selected from p-aminomethylaniline-diglycolic acid (pABzA-DIG), 4-amino-(1-carboxymethyl)piperidine (Pip), 9-amino-4,7-dioxanonanoic acid (dPEG2), or 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp); Xaa1is D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala);Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is statine (Sta), Leu, D-Pro, or Phe; R is -NH2or -NHOH; m2 is 0 or 1; when m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; Xaa13is an amino acid with a sidechain comprising a carboxylic acid, wherein one Xaa12is bonded to the C-terminus of Xaa13and the other Xaa12is bonded to the sidechain of Xaa13; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; the linker absent or is a linear or branched chain of n1 units of -Xaa11-, wherein: n1 is 1-6; each Xaa11is independently an amino acid; Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated.

[0099] In some embodiments of the peptidic compound of formula (B), the compound has the structure: Rradn6-RL-[linker]-Xaa13-[Xaa12-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-ψ-Xaa9-(Xaa10)m-R]2.

[0100] In some embodiments of the peptidic compound of formula (B) or (B-1), both Xaa12is the same amino acid. In some embodiments, each Xaa12is the same or different amino acids.

[0101] In some embodiments of the peptidic compound of formula (B) or (B-1), both Xaa1is the same amino acid. In some embodiments, each Xaa1is the same or different amino acids.

[0102] In some embodiments of the peptidic compound of formula (B) or (B-1), both Xaa2is the same amino acid. In some embodiments, each Xaa2is the same or different amino acids.

[0103] In some embodiments of the peptidic compound of formula (B) or (B-1), both Xaa3is the same amino acid. In some embodiments, each Xaa3is the same or different amino acids.

[0104] In some embodiments of the peptidic compound of formula (B) or (B-1), both Xaa4is the same amino acid. In some embodiments, each Xaa4is the same or different amino acids.

[0105] In some embodiments of the peptidic compound of formula (B) or (B-1), both Xaa5is the same amino acid. In some embodiments, each Xaa5is the same or different amino acids.

[0106] In some embodiments of the peptidic compound of formula (B) or (B-1), both Xaa6is the same amino acid. In some embodiments, each Xaa6is the same or different amino acids.

[0107] In some embodiments of the peptidic compound of formula (B) or (B-1), both Xaa7is the same amino acid. In some embodiments, each Xaa7is the same or different amino acids.

[0108] In some embodiments of the peptidic compound of formula (B) or (B-1), both Xaa8is the same amino acid. In some embodiments, each Xaa8is the same or different amino acids.

[0109] In some embodiments of the peptidic compound of formula (B) or (B-1), both Xaa9is the same amino acid. In some embodiments, each Xaa9is the same or different amino acids.

[0110] In some embodiments of the peptidic compound of formula (B) or (B-1), both Xaa10is the same amino acid. In some embodiments, each Xaa10is the same or different amino acids.

[0111] In some embodiments of the compounds of formula (B) or (B-1), Xaa1is D-Phe. Insome embodiments, Xaa1is Cpa or D-Cpa. In some embodiments, Xaa1is NaI, D-NaI, 2-NaI, D-2-NaI. In some embodiments, Xaa1is D-Cpa, Tpi, D-Tpi or D-Nal.

[0112] In some embodiments of the compounds of formula (B) or (B-1), Xaa12is Pip.

[0113] In some embodiments of the compounds of formula (B) or (B-1), Xaa13is Glu, D-Glu, Asp, or D-Asp. In some embodiments, Xaa13is Glu.

[0114] In some embodiments of the compounds of formula (B) or (B-1), the linker is absent.

[0115] In some embodiments of the compounds of formula (B) or (B-1), the linker is a linear or branched chain of n1 units of -Xaa11-, wherein n1 is 1-3, and each Xaa11is independently 2-aminoadipic acid (2˗Aad) or 3-aminoadipic acid (3˗Aad). In some embodiments, each Xaa11is 2-Aad. In some embodiments, the linker is -2-Aad-2-Aad-.

[0116] In some embodiments of the compounds of formula (B) or (B-1), n1 is 1, 2, or 3.

[0117] In some embodiments of the compounds of formula (B) or (B-1), Rradis a radiometal chelator. In some embodiments, the radiometal chelator is bound to a radiometal. As used herein, phrases that a radiometal is “bound to a chelator,” “chelated to a chelator,” “conjugated to a chelator,” “conjugated with a chelator,” and “associated with a chelator“ are used interchangeably.

[0118] In some embodiments of the peptidic compound (e.g., compounds of formula (A), (I), (IA), (IA-1), (IB), (IB-1), (IC), (IC-1), (ID), (ID-1), (IE), (IE-1), (IF), (IF-1), (II), (IIA), (B), or (B-1) or salt or solvate thereof), R is -NH2.

[0119] In some embodiments of the peptidic compound, ψ represents a reduced peptide bond. In some embodiments, ψ represents a peptide bond.

[0120] In some embodiments of the peptidic compound, Xaa1is an N-terminal amino acid residue selected from D-Phe.

[0121] In some embodiments of the peptidic compound, Xaa2is Gln. In some embodiments, Xaa2is Cit. In some embodiments, Xaa2is Glu. In some embodiments, Xaa2is Agb. In some embodiments, Xaa2is Asn, Gln, or Hse. In some embodiments, Xaa2is Gln, Cit, Glu, or Agb. In some embodiments, Xaa2is Gln or Cit.

[0122] In some embodiments of the peptidic compound, Xaa3is Trp. In some embodiments, Xaa3is αMe-Trp. In some embodiments, Xaa3is Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala). In some embodiments, Xaa3is Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(5-OH), or αMe-Trp. In some embodiments, Xaa3is Trp, Trp(7-F), or αMe-Trp.

[0123] In some embodiments of the peptidic compound, Xaa4is Ala. In some embodiments, Xaa4is Ser.

[0124] In some embodiments of the peptidic compound, Xaa5is Val or Tle. In some embodiments, Xaa5is Val. In some embodiments, Xaa5is Tle. In some embodiments, Xaa5is Cpg.

[0125] In some embodiments of the peptidic compound, Xaa6is Gly or NMe-Gly. In some embodiments, Xaa6is Gly. In some embodiments, Xaa6is NMe-Gly. In some embodiments, Xaa6is Gly, NMe-Gly, or D-Ala.

[0126] In some embodiments of the peptidic compound, Xaa7is His. In some embodiments of the peptidic compound, Xaa7is Trp. In some embodiments of the peptidic compound, Xaa7is Trp(5-F). In some embodiments, Xaa7is Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), or αMe-Trp. In some embodiments, Xaa7is NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala). In some embodiments, Xaa7is His, Trp, Trp(5-F), or 3-Quin-Ala.

[0127] In some embodiments of the peptidic compound, Xaa8is Leu. In some embodiments, Xaa8is Sta. In some embodiments, Xaa8is D-Pro or Phe. In some embodiments, Xaa8is cis-4-cyclohexyloxy-D-Pro or cis-4-cyclohexylamino-D-Pro.

[0128] In some embodiments of the peptidic compound, Xaa8-R is a C-terminally amidated cis-4-cyclohexyloxy-D-Pro or cis-4-cyclohexylamino-D-Pro.

[0129] In some embodiments of the peptidic compound, Xaa9-R is a C-terminally amidated Pro or Leu. In some embodiments of the peptidic compound, Xaa9-R is a C-terminally amidated Pro. In some embodiments of the peptidic compound, Xaa9-R is a C-terminally amidated Leu. In some embodiments of the peptidic compound, Xaa9-R is a C-terminally amidated Phe, diFPro, 4-oxa-Pro, Me2Thz, or Thz. In some embodiments, Xaa9-R is a C-terminally amidated cis-4-cyclohexyloxy-D-Pro or cis-4-cyclohexylamino-D-Pro.

[0130] In some embodiments of the peptidic compound, Xaa9is Pro or Leu. In some embodiments of the peptidic compound, Xaa9is Pro. In some embodiments of the peptidic compound, Xaa9is Leu.

[0131] In some embodiments of the peptidic compound, Xaa10-R is a C-terminally amidated Val or Tle. some embodiments of the peptidic compound, Xaa10-R is a C-terminally amidated Val. some embodiments of the peptidic compound, Xaa10-R is a C-terminally amidated Tle.

[0132] In some embodiments of the peptidic compound, Xaa1is an N-terminal amino acid residue selected from D-Phe; Xaa2is Gln, Cit, Glu, or Agb; Xaa3is Trp or αMe-Trp; Xaa4is Ala;Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; Xaa7is His, Trp, Trp(5-F), or 3-Quin-Ala; Xaa8is Leu or Sta; and Xaa9-R is a C-terminally amidated Pro or Leu.

[0133] In some embodiments of the peptidic compound, Xaa1is an N-terminal amino acid residue selected from D-Phe; Xaa2is Gln, Cit, Glu, or Agb; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly or NMe-Gly; Xaa7is His, Trp, or Trp(5-F); Xaa8is Leu or Sta; Xaa9is Pro or Leu; and Xaa10-R is a C-terminally amidated Val or Tle.

[0134] In some embodiments of the peptidic compound, at least one of Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is N-methylated. In some embodiments, at least one of Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, or Xaa8is N-methylated. For example, if the compound has a definition of Xaa4as Ala, D-Ala, or Ser, then it also includes options for NMe-Ala, NMe-D-Ala, or NMe-Ser as Xaa4.

[0135] In some embodiments, Xaa6is N-methylated.

[0136] In a specific embodiment, the compounds of formula (A), (I), (IA), (IB), (IC), (ID), (IE), (B), (B-1) do not comprise an albumin binder Ralbin the linker.

[0137] In some embodiments of the peptidic compound (e.g., compound of formula (A), (I), (IA), (IA-1), (IB), (IB-1), (IC), (IC-1), (ID), (ID-1), (IE), (IE-1), (IF), (IF-1), (II), (IIA), (B), or (B-1)), ψ is a reduced peptide bond joining Xaa8to Xaa9, wherein Xaa8is Leu and Xaa9is Pro. In some embodiments, the reduced peptide bond joining Xaa8and Xaa9means that the main chain amide (e.g., ) formed between Xaa8and Xaa9is replaced by .

[0138] In some embodiments of the peptidic compound, ψ is a peptide bond joining Xaa8and Xaa9.

[0139] In some embodiments of the peptidic compound, RLis a linkage moiety joining the linker to the N-terminus of Xaa1or joining the linker and Rrad. In some embodiments, RLis –C(O)–. In other embodiments, RLis –NH–C(O)–. In yet other embodiments, RLis –NH–C(S)–. In some embodiments, RLis –(C1-3alkyl)–. In some embodiments, RLis –CH2–. In some embodiments, RLis –(C1-3alkyl)-C(O)–. In some embodiments, RLis –CH2–C(O)–.

[0140] In some embodiments of the peptidic compound, the linker and RLtogether form a Pip linker. In some embodiments, the linker and RLtogether comprises a Pip linker.

[0141] In some embodiments of the peptidic compound, a non-limiting example of a suitable linker is a peptide linker. More generally, the linker is a linear or branched chain of n1 units of –L1R1– and / or –(L1)2R1– (i.e. each unit is independently –L1R1– or –(L1)2R1–), wherein n1 is 1-20. In alternative embodiments, n1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20. In some embodiments, n1 is 1-7. In some embodiments, n1 is 1. In other embodiments, n1 is 2. In other embodiments, n1 is 3. In other embodiments, n1 is 4. In other embodiments, n1 is 5. In other embodiments, n1 is 6. In other embodiments, n1 is 7.

[0142] In some embodiments of the peptidic compound, the linker is a linear or branched chain of n1 units of -Xaa11-, wherein each Xaa11is independently an amino acid and n1 is 1-10. In some embodiments, the linker is a linear or branched chain of n1 units of -Xaa11-, wherein each Xaa11is independently an amino acid and n1 is 1-6. In some embodiments, the linker comprises Ralbbonded to a free N-terminus of a Xaa11. In some embodiments, the linker comprises Ralbbonded to a side chain of a Xaa11. In some embodiments, at least one Xaa11is Lys. In some embodiments, at least one Xaa11is Lys and Ralbis bonded to the side chain the Lys.

[0143] In some embodiments of the peptidic compound, the linker is a linear peptide of 3 to 6 amino acid residues, –Xaa11A–Xaa11B–(Xaa11C)1˗4–, wherein Xaa11A, Xaa11B, and Xaa11Care each independently an amino acid and wherein the radiolabeling group and the albumin-binding group are bonded to the free N-terminus of Xaa11Aand the side chain of Xaa11B, respectively, or are bonded to the side chain of Xaa11Band the free N-terminus of Xaa11A, respectively. In some embodiments, Xaa11Ais Gly, Glu, D-Glu, Asp, D-Asp, 2˗Aad, D-2-Aad, 3-Aad, or D-3-Aad. In some embodiments, Xaa11Ais Gly, Glu or D-Glu. In some embodiments, Xaa11Ais Gly. In some embodiments, Xaa11Bis Lys, Orn, D-Orn, Dab, D-Dab, Dap or D-Dap, any of which can form an amide bond with a carboxylate of a radiolabeling group or an albumin binding group. In some embodiments, Xaa11Bis Lys or D-Lys. In some such embodiments, (Xaa11C)1-4is diglycine. In some such embodiments, (Xaa11C)1-4is p-aminomethylaniline-diglycolic acid (pABzA-DIG), a 4-amino-(1-carboxymethyl)piperidine (Pip), a 9-amino-4,7-dioxanonanoic acid (dPEG2), or a 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp). In some such embodiments, (Xaa11C)1-4is Pip. In some embodiments, the C-terminus of Xaa11Cand the N-terminus of Xaa1are bonded.

[0144] In some embodiments of the peptidic compound, the linker is a branched peptide of 3 to 6 amino acid residues, –Xaa11B(Xaa11A)–(Xaa11C)1-4–, wherein Xaa11A, Xaa11B, and Xaa11Care each independently an amino acid and wherein the C-terminus of Xaa11Aforms an amide with the side chain of Xaa11B, and wherein the radiolabeling group and the albumin-binding group are bonded to the free N-termini of Xaa11Aand Xaa11B, respectively, or are bonded to the free N-termini of Xaa11Band Xaa11A, respectively. In some embodiments, Xaa11Ais Gly, Glu, D-Glu, Asp, D-Asp, 2˗Aad, D-2-Aad, 3-Aad, or D-3-Aad. In some embodiments, Xaa11Ais Glu or D-Glu. In some embodiments, Xaa11Bis Lys, D-Lys, Orn, D-Orn, Dab, D-Dab, Dap or D-Dap. In some embodiments, Xaa11Bis Lys or D-Lys. In some such embodiments, (Xaa11C)1-4is diglycine. In some such embodiments, (Xaa11C)1-4is p-aminomethylaniline-diglycolic acid (pABzA-DIG), a 4-amino-(1-carboxymethyl)piperidine (Pip), a 9-amino-4,7-dioxanonanoic acid (dPEG2), or a 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp). In some such embodiments, (Xaa11C)1-4is Pip. In some embodiments, the C-terminus of Xaa11Cand the N-terminus of Xaa1are bonded.

[0145] In some embodiments of the peptidic compound, the linker is a linear peptide of 3 amino acid residues, –Xaa11A–Xaa11B–Xaa11C–, wherein Xaa11A, Xaa11B, and Xaa11Care each independently an amino acid and wherein the radiolabeling group and the albumin-binding group are bonded to the free N-terminus of Xaa11Aand the side chain of Xaa11B, respectively, or are bonded to the side chain of Xaa11Band the free N-terminus of Xaa11A, respectively. In some embodiments, Xaa11Ais Gly, Glu, D-Glu, Asp, D-Asp, 2˗Aad, D-2-Aad, 3-Aad, or D-3-Aad. In some embodiments, Xaa11Ais Gly, Glu or D-Glu. In some embodiments, Xaa11Ais Gly. In some embodiments, Xaa11Bis Lys, D-Lys, Orn, D-Orn, Dab, D-Dab, Dap or D-Dap, any of which can form an amide bond with a carboxylate of a radiolabeling group or an albumin binding group. In some embodiments, Xaa11Bis Lys or D-Lys. In some such embodiments, Xaa11Cis p-aminomethylaniline-diglycolic acid (pABzA-DIG), a 4-amino-(1-carboxymethyl)piperidine (Pip), a 9-amino-4,7-dioxanonanoic acid (dPEG2), or a 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp). In some such embodiments, Xaa11Cis Pip. In some embodiments, the C-terminus of Xaa11Cand the N-terminus of Xaa1are bonded.

[0146] In some embodiments of the peptidic compound, the linker is -Gly-Lys-Pip-. In some embodiments, the radiolabeling group is bonded to the free N-terminus of Xaa11Aand the albumin-binding group is bonded to the side chain of Xaa11B. In some embodiments, the radiolabeling group is bonded to the free N-terminus of Gly and the albumin-binding group is bonded to the side chain of Lys. In some embodiments, the C-terminus of Pip and the N-terminus of Xaa1are bonded.

[0147] In some embodiments of the peptidic compound, the linker is a branched peptide of 3 amino acid residues, –Xaa11B(Xaa11A)–Xaa11C–, wherein Xaa11A, Xaa11B, and Xaa11Care each independently an amino acid and wherein the C-terminus of Xaa11Aforms an amide with the side chain of Xaa11B, and wherein the radiolabeling group and the albumin-binding group are bonded to the free N-termini of Xaa11Aand Xaa11B, respectively, or are bonded to the free N-termini of Xaa11Band Xaa11A, respectively. In some embodiments, Xaa11Ais Gly, Glu, D-Glu, Asp, D-Asp, 2˗Aad, D-2-Aad, 3-Aad, or D-3-Aad. In some embodiments, Xaa11Ais Glu or D-Glu. In some embodiments, Xaa11Bis Lys, D-Lys, Orn, D-Orn, Dab, D-Dab, Dap or D-Dap. In some embodiments, Xaa11Bis Lys or D-Lys. In some such embodiments, Xaa11Cis p-aminomethylaniline-diglycolic acid (pABzA-DIG), a 4-amino-(1-carboxymethyl)piperidine (Pip), a 9-amino-4,7-dioxanonanoic acid (dPEG2), or a 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp). In some such embodiments, Xaa11Cis Pip. In some embodiments, the C-terminus of Xaa11Cand the N-terminus of Xaa1are bonded.

[0148] In some embodiments of the peptidic compound, RLbetween Xaa11of the linker and Xaa1is absent and Xaa11of the linker joins with the N-terminus of Xaa1. In someembodiments, RLbetween Xaa11of the linker and Xaa1is absent and Xaa11of the linker joins with the N-terminus of Xaa1by forming an amide bond (i.e., peptide bond between Xaa11-Xaa1).

[0149] In some embodiments of the peptidic compound, the linker and RLtogether formn some embodiments the linker is .

[0150] In some embodiments of the peptidic compound, an albumin binder (Ralb) is bonded to the linker. In some embodiments of the peptidic compound, the linker does not comprise Ralb.

[0151] In some embodiments of the peptidic compound, n6 is 1-5. In some embodiments, n6 is 1. In other embodiments, n6 is 2. In other embodiments, n6 is 3. In other embodiments, n6 is 4. In other embodiments, n6 is 5.

[0152] In some embodiments of the peptidic compound, n6 is 1 and n1 is 1. In some embodiments, n6 is 1, n1 is 1, and L1is –C(O)NH–. In some embodiments, n6 is 1, n1 is 1, L1is –C(O)NH–, and RLis –C(O)–. In some embodiments, n6 is 1, n1 is 1, L1is –C(O)NH–, RLis –C(O)–, and R1is a linear C1-5alkylenyl or –(CH2)2–[O(CH2)2]1-6–(CH2)0-2.

[0153] In some embodiments of the peptidic compound, Rradn6-[linker]- is configured as shown in Formula (a): (a), wherein L1and R1are as defined in the definition of the linker in Formula a, and Rrad / albis either Rrador Ralb, and wherein 0-1 Rrad / albis Ralb.

[0154] In some embodiments of the peptidic compound, R1is, independently, a linear, branched, and / or cyclic C1-20alkylenyl, C2-20alkenylenyl and / or C2-20alkynylenyl, wherein any carbon bonded to two other carbons is optionally independently replaced by N, S, or O, and carbons are optionally independently substituted. In some embodiments, R1is, independently, a linear, branched, and / or cyclic C1-15alkylenyl, C2-15alkenylenyl and / or C2-15alkynylenyl, wherein any carbon bonded to two other carbons is optionally independently replaced by N,S, or O, and carbons are optionally independently substituted. In some embodiments, R1is, independently, a linear, branched, and / or cyclic C1-10alkylenyl, C2-10alkenylenyl and / or C2-10alkynylenyl, wherein any carbon bonded to two other carbons is optionally independently replaced by N, S, or O, and carbons are optionally independently substituted. In some embodiments, R1is, independently, a linear, branched, and / or cyclic C1-10alkylenyl. In some embodiments, each R1is independently a linear C1-5alkylenyl or –(CH2)2–[O(CH2)2]1-6–(CH2)0-2–.

[0155] In some embodiments of the peptidic compound, n1 is 1-7. In some embodiments, each R1is independently –C(Raa)H–, wherein each Raais independently the sidechain of a proteinogenic amino acid or the sidechain of an alpha amino acid from Table A. In some embodiments, each R1is independently a proteinogenic amino acid or an amino acid from Table A omitting the backbone amino and carboxylic acid groups of the amino acid.

[0156] In some embodiments of the peptidic compound, L1is a linkage group. In some embodiments, at least one L1is –S–. In some embodiments, at least one L1is –N(R2)C(O)–; in some of these embodiments, at least one R2is hydrogen. In some embodiments, at least one L1is –C(O)N(R2)–; in some of these embodiments, at least one R2is hydrogen. In some embodiments, at least one L1is –NH–C(O)–NH–. In some embodiments, at least one L1is–NH–C(S)–NH–. In some embodiments, at least one L1is . In some embodiments, at least one L1is . In some embodiments, at least one L1is . In some embodiments, at least one L1is .

[0157] In some embodiments of the peptidic compound, the linker has the configuration shown in Formula a, and each R1is independently a linear C1-5alkylenyl or –(CH2)2–[O(CH2)2]1-6–(CH2)0-2–.

[0158] In some embodiments of the peptidic compound, n6 is 1, the linker is L1R1and together with RLforms –C(O)–Xaa11– wherein Xaa11is a proteinogenic amino acid residue or an amino acid residue selected from Table A. In some embodiments, Xaa11is pABzA-DIG. In other embodiments, Xaa11is Pip. In other embodiments, Xaa11is dPEG2. In other embodiments, Xaa11is Acp.

[0159] In some embodiments of the peptidic compound, the linker together with RLforms a peptide linker, wherein peptide (amide) bonds are independently optionally methylated, optionally replacing one or more amide bonds with 1,2,3-triazole linkages (product of a reaction between an azide and an alkyne). In some embodiments, the peptide linker is a linearpeptide linker, optionally replacing one or more amide bonds with 1,2,3-triazole linkages. In some embodiments, the peptide linker is a branched peptide linker, where the amino acid residues may be connected through a combination of main chain amide (peptide) bonds and ‘side chain’-to-‘main chain’ or ‘side chain’-to-‘side chain’ bonds. For example, a branched peptide may be connected by one or more of: backbone (main chain) peptide (amide) bonds, ‘main chain’-to-side chain amide bonds (between an amino group and a carboxylic acid group), optionally replacing one or more amide bonds with 1,2,3-triazole linkages. In some such embodiments, the peptide linker is (XaaA)1-20, wherein each XaaAis independently a proteinogenic amino acid residue or a non-proteinogenic amino acid residue (e.g., selected from Table A) linked together as a linear or branched peptide linker. In some embodiments, (XaaA)1-20is a linear peptide linker. In some embodiments, (XaaA)1-20is a branched peptide linker. Rradis bonded to the peptide linker through an amide bond or another L1linkage group; in some embodiments, Rradis bonded to the peptide linker through an amide bond.

[0160] In some embodiments, each XaaAis independently –N(Ra)RbC(O)– wherein: Ramay be H or methyl; Rbmay be a 1- to 30-atom alkylenyl, heteroalkylenyl, alkenylenyl, heteroalkenylenyl, alkynylenyl, or heteroalkynylenyl, including linear, branched, and / or cyclic (whether aromatic or nonaromatic as well as mono-cyclic, multicyclic or fused cyclic) structures; or N, Raand Rbtogether may form a 5- to 7-atom heteroalkylenyl or heteroalkenylenyl.

[0161] In some embodiments, (XaaA)1-20consists of a single amino acid or residue. In some embodiments, (XaaA)1-20is a dipeptide, wherein each XaaAmay be the same or different. In some embodiments, (XaaA)1-20is a tripeptide, wherein each XaaAmay be the same, different or a combination thereof. In some embodiments, (XaaA)1-20consists of 4 amino acid residues connected by peptide bonds, wherein each XaaAmay be the same, different or a combination thereof. In some embodiments, each XaaAis independently selected from proteinogenic amino acids and the non-proteinogenic amino acids listed in Table A, wherein each peptide backbone amino group of the peptide linker is independently optionally methylated. In some embodiments, all peptide backbone amino groups of the peptide linker are methylated. In other embodiments, only one peptide backbone amino group of the peptide linker is methylated. In other embodiments, only two peptide backbone amino groups of the peptide linker are methylated. In other embodiments, no peptide backbone amino groups of the peptide linker are methylated.

[0162] In some embodiments of the peptidic compound, Ralbis -(CH2)n3-CH3wherein n3 is 8-20. In some embodiments, n3 is 8-15.

[0163] In some embodiments of the peptidic compound, Ralbis -(CH2)n4-C(O)OH wherein n4 is 8-20. In some embodiments, n4 is 8-15.

[0164] In some embodiments of the peptidic compound, Ralbiswherein n2 is 1-5, n5 is 1-4, and each R3ais independently H or methyl, and each R3bindependently is I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl. In some embodiments, n2 is 1. In some embodiments, n5 is 1, 2, 3, or 4. In some embodiments, each R3ais H. In some embodiments, each R3ais methyl. In some embodiments, each R3bis I, Br, F, or Cl, optionally in para position. In some embodiments, R3bis H. In some embodiments, R3bis OH, optionally in para position. In some embodiments, R3bis OCH3, optionally in para position. In certain embodiments, R3bis NH2, optionally in para position. In some embodiments, R3bis NO2, optionally in para position. In some embodiments, R3bis C1-C6alkyl, optionally in para position. In some embodiments, R3ais H and R3bis OCH3or NO2.

[0165] In some embodiments of the peptidic compound, Ralbis . In some embodiments, Ralbis . In some embodiments, R3bis I, Br, F, Cl, H, OH, OCH3, NH2, or NO2.

[0166] In some embodiments of the peptidic compound, Ralbis wherein n5 is 1-4 and each R3ais independently H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl. In some embodiments, each R3ais H. In some embodiments, each R3ais methyl. In some embodiments, R3bis I, Br, F, or Cl, optionally in para position. In some embodiments, R3bis H. In some embodiments, R3bis OH, optionally in para position. In some embodiments, R3bis OCH3, optionally in para position. In some embodiments, R3bis NH2, optionally in para position. In certain embodiments, R3bis NO2, optionally in para position. In some embodiments, R3bis C1-C6alkyl, optionally in para position. In some embodiments, R3ais H and R3bis OCH3or NO2.

[0167] In some embodiments of the peptidic compound, Ralbis.

[0168] In some embodiments, at least one Rradis or comprises a radiometal chelator. The radiometal chelator may be any chelator suitable for binding a radiometal, a radionuclide-bound metal, or a radionuclide-bound metal-containing prosthetic group, and which is attached to the linker by forming an amide bond (between an amino group and a carboxylic acid group) or a 1,2,3-triazole (reaction between an azide and an alkyne), or by reaction between a maleimide and a thiol group. Many suitable radiometal chelators are known, e.g., as summarized in Price and Orvig, Chem. Soc. Rev., 2014, 43, 260-290. In some embodiments, but without limitation, each radiometal chelator is independently selected from the group consisting of: DOTA and DOTA derivatives; DOTAGA (2-(4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododecan-1-yl)pentanedioic acid); PSC (1,4,7,10-tetraazacyclododecane- 1,4,7,10-tetriacetic acid); NOTA; NODAGA; NODASA; CB-DO2A; 3p-C-DEPA; TCMC (also known as DOTAM); DO3A; DTPA and DTPA analogues optionally selected from CHX-A”-DTPA and 1B4M-DTPA; TETA; NOPO; Me-3,2-HOPO; CB-TE1A1P; CB-TE2P; MM-TE2A; DM-TE2A; sarcophagine and sarcophagine derivatives optionally selected from SarAr, SarAr-NCS, diamSar, AmBaSar, and BaBaSar; TRAP; AAZTA; DATA and DATA derivatives; H2-macropa or a derivative thereof; H2dedpa, H4octapa, H4py4pa, H4Pypa, H2azapa, H5decapa, and other picolinic acid derivatives; CP256; PCTA; C-NETA; C-NE3TA; HBED; SHBED; BCPA; CP256; YM103; desferrioxamine (DFO) and DFO derivatives; H6phospa; a trithiol chelate; mercaptoacetyl; hydrazinonicotinamide; dimercaptosuccinic acid; 1,2-ethylenediylbis-L-cysteine diethyl ester; methylenediphosphonate; hexamethylpropyleneamineoxime; and hexakis(methoxy isobutyl isonitrile). In some embodiments, at least one radiometal chelator is DOTA or a DOTA derivative.

[0169] In some embodiments, when Rradis a radiometal chelator, an atom or a chemical group of the radiometal chelator is replaced to form a covalent bond to the linker. For example, a hydroxyl group (-OH) of a carboxylic acid of DOTA is replaced with a covalent bond to the linker. In another example, an amine group (-NH2) of an acetamide of TCMC is replaced with a covalent bond to the linker.

[0170] In some embodiments, when Rradis DOTA and –RL-[linker]-RL-, –[linker]-RL-, or –[linker]- is Pip, and Rrad–[linker]-RL- has the structure: n some embodiments, when Rradis DOTA andRL-[linker]-RL-, –[linker]-RL-, or –[linker]- is Pip, and Rrad–RL-[linker]-RL-Xaa1- Rrad–[linker]-RL-Xaa1- or Rrad–[linker]-Xaa1- has the structure

[0171] In some embodiments, when Rradis DOTAGA and –RL-[linker]-RL-, –[linker]-RL-, or –[linker]- is Pip, and Rrad–[linker]-RL- has the structure: . In some embodiments, when Rradis DOTAGA and RL-[linker]-RL-, –[linker]-RL-, or –[linker]- is Pip, and Rrad–RL-[linker]-RL-Xaa1- Rrad–[linker]-RL-Xaa1- or Rrad–[linker]-Xaa1- has the structure: .

[0172] In some embodiments, when Rradis CROWN and –RL-[linker]-RL-, –[linker]-RL-, or –[linker]- is Pip, and Rrad–RL-[linker]-RL-Xaa1- Rrad–[linker]-RL-Xaa1- or Rrad–[linker]-Xaa1- has the structure: . In some embodiments, when Rradis CROWN and –RL-[linker]-RL-, –[linker]-RL-, or –[linker]- is Pip, and RradRrad–RL-[linker]-RL-Xaa1- Rrad–[linker]-RL-Xaa1- or Rrad–[linker]-Xaa1- has the structure:

[0173] In some embodiments, when Rradis CROWNGA and –RL-[linker]-RL-, –[linker]-RL-, or –[linker]- is Pip, and Rrad–RL-[linker]-RL-Xaa1- Rrad–[linker]-RL-Xaa1- or Rrad–[linker]-Xaa1- has the structure: . In some embodiments, when Rradis CROWNGA and –RL-[linker]-RL-, –[linker]-RL-, or –[linker]- is Pip, and RradRrad–RL-[linker]-RL-Xaa1- Rrad–[linker]-RL-Xaa1- or Rrad–[linker]-Xaa1- has the structure: .

[0174] In some embodiments, when Rradis TCMC and –RL-[linker]-RL-, –[linker]-RL-, or –[linker]- is Pip, and Rrad–[linker]-RL- has the structure: .

[0175] In some embodiments, when Rradis PSC and –RL-[linker]-RL-, –[linker]-RL-, or –[linker]- is Pip, and Rrad–RL-[linker]-RL-Xaa1- Rrad–[linker]-RL-Xaa1- or Rrad–[linker]-Xaa1- has the structure:

[0176] TABLE B: Exemplary radiometal chelators and exemplary radiometals

[0177] In some embodiments of the peptidic compound, each radiometal chelator is independently selected from Table B, wherein each chelator is optionally bound by a radiometal. In some embodiments, each radiometal chelator is bound by one of the corresponding radiometal shown in Table B. In some embodiments, the radiometal chelator is bound by a radiometal, a radionuclide-bound metal, or a radionuclide-bound metal-containing prosthetic group.

[0178] In some embodiments of the peptidic compound, at least one Rradis DOTA, or a derivative thereof, linked via an amide (e.g., formed from one of the carboxyl groups shown in Table B. In some embodiments, at least one Rradis CB-DO2A, or a derivative thereof, linked via an amide (e.g., formed from one of the carboxyl groups shown in Table B). In some embodiments, at least one Rradis TCMC, or a derivative thereof, linked via an amide (e.g., formed from one of the –CONH2groups shown in Table B). In some embodiments, the chelator at least one Rradis 3p-C-DEPA, or a derivative thereof, linked via an amide (e.g., formed from one of the carboxyl groups shown in Table B). In some embodiments, at least one Rradis p-NH2-Bn-Oxo-DO3A or a derivative thereof, linked via an amide (e.g., formed from one of the carboxyl groups shown in Table B). In some embodiments, at least one Rradis TETA, ora derivative thereof, linked via an amide (e.g., formed from one of the carboxyl groups shown in Table B). In some embodiments, at least one Rradis CB-TE2A, or a derivative thereof, linked via an amide (e.g., formed from one of the carboxyl groups shown in Table B). In some embodiments, at least one Rradis Diamsar, or a derivative thereof, linked via an amide (e.g., formed from one of the amino groups shown in Table B). In some embodiments, at least one Rradis NOTA, or a derivative thereof, linked via an amide (e.g., formed from one of the carboxyl groups shown in Table B). In some embodiments, at least one Rradis NETA, or a derivative thereof, linked via an amide (e.g., formed from one of the carboxyl groups shown in Table B). In some embodiments, at least one Rradis HxTSE, or a derivative thereof, linked via an amide (e.g., formed from one of the amino groups shown in Table B). In some embodiments, at least one Rradis P2N2Ph2, or a derivative thereof, linked via an amide (e.g., formed from one of the amino groups shown in Table B). In some embodiments, at least one Rradis DTPA, or a derivative thereof, linked via an amide (e.g., formed from one of the carboxyl groups shown in Table B). In some embodiments, at least one Rradis CHX-A00-DTPA, or a derivative thereof, linked via an amide (e.g., formed from one of the carboxyl groups shown in Table B). In some embodiments, at least one Rradis H2dedpa, or a derivative thereof, linked via an amide (e.g., formed from one of the carboxyl groups shown in Table B). In some embodiments, at least one Rradis H2azapa, or a derivative thereof, linked via an amide (e.g., formed from one of the carboxyl groups shown in Table B). In some embodiments, at least one Rradis H4octapa, or a derivative thereof, linked via an amide (e.g., formed from one of the carboxyl groups shown in Table B). In some embodiments, at least one Rradis H6phospa, or a derivative thereof, linked via an amide (e.g., formed from one of the carboxyl groups shown in Table B). In some embodiments, at least one Rradis H4CHXoctapa, or a derivative thereof, linked via an amide (e.g., formed from one of the carboxyl groups shown in Table B). In some embodiments, at least one Rradis H5decapa, or a derivative thereof, linked via an amide (e.g., formed from one of the carboxyl groups shown in Table B). In some embodiments, at least one Rradis H4neunpa-p-Bn-NO2, or a derivative thereof, linked via an amide (e.g., formed from one of the carboxyl groups shown in Table B). In some embodiments, at least one Rradis SHBED, or a derivative thereof, linked via an amide (e.g., formed from one of the carboxyl groups shown in Table B). In some embodiments, at least one Rradis BPCA, or a derivative thereof, linked via an amide (e.g., formed from one of the carboxyl groups shown in Table B). In some embodiments, at least one Rradis PCTA, or a derivative thereof, linked via an amide (e.g., formed from one of the carboxyl groups shown in Table B). In some embodiments, at least one Rradis H2-MACROPA, or a derivative thereof, linked via an amide (e.g., formed from one of the carboxyl groups shown in Table B). In some embodiments, at least one Rradis CROWN, or a derivative thereof, linked via an amide (e.g., formed from one of the carboxyl groups shown in Table B). In some embodiments, at least one Rradis CROWNGA, or a derivative thereof, linkedvia an amide (e.g., formed from one of the carboxyl groups shown in Table B). In some embodiments, at least one Rradis HYNIC, or a derivative thereof, linked via an amide (e.g., formed from the carboxyl group shown in Table B). In some embodiments, at least one Rradis N4, or a derivative thereof, linked via an amide (e.g., formed from the carboxyl group shown in Table B). In some embodiments, at least one Rradis HBED-CC, or a derivative thereof, linked via an amide (e.g., formed from one of the carboxyl groups shown in Table B).

[0179] In some embodiments of the peptidic compound, the radiometal chelator (or one of the radiometal chelators) is a derivative of a radiometal chelator shown in Table B. A derivative may include, e.g., (1) modification of a functional group of the chelator (e.g., a carboxyl group, an amino group, etc.) or (2) attachment of a new functional group (e.g., attachment of an R-group to an ethylene carbon located between two nitrogen atoms, wherein the R-group is a functional group fused to a spacer). In some embodiments, a carboxyl functional group shown in Table B is replaced with azidopropyl ethylacetamide (e.g., azido-mono-amide-DOTA), butynylacetamide (e.g., butyne-DOTA), thioethylacetamide (e.g., DO3A-thiol), maleimidoethylacetamide (e.g., maleimido-mono-amide-DOTA), or N-hydroxysuccinimide ester (e.g., DOTA-NHS-ester). When linked, these derivative chelators can be linked either via an amide (formed from a remaining carboxyl group) or via –C(O)–NH–(CH2)2-3–(triazole) or –C(O)–NH–(CH2)2-3–(thiomaleimide). In other embodiments, a backbone carbon (e.g., in an ethylene positioned between two backbone nitrogen atoms) in the chelator ring is fused to an R-group containing a functional group, optionally wherein the R-group is –(CH2)1-3–(phenyl)–N=C=S or –(CH2)1-3–(phenyl)–N=C=O, optionally 1,4-isothiocyanatobenzyl; e.g., p-SCN-Bn-DOTA (S-2-(4-isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane tetraacetic acid), p-SCN-Bn-NOTA (2-S-(4-isothiocyanatobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid), and the like. When linked, these derivatives can form a urea linkage (formed from isocyanate) or a thiourea linkage (formed from isothiocyanate).

[0180] In some embodiments of the peptidic compound, the radiometal chelator is 1,4,7,10-tetraazacyclotetradecane-1,4,7,10-tetraacetic acid (DOTA), 2-(4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododecan-1-yl)pentanedioic acid (DOTAGA), 1,4,7-triazacyclononane-triacetic acid (NOTA), 1,4,7-triazacyclononane-1-glutaric acid-4,7-diacetic acid (NODAGA), 1,4,7-Triazacyclononane-1-succinic acid-4,7-diacetic acid (NODASA), 1,8-N,N’-bis-(carboxymethyl)-1,4,8,11- tetraazacyclotetradecane (TE2A), 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13- triene-3,6,9-triacetic acid (PCTA), 1-substituted 1,4,7,-tricarboxymethyl-1,4,7,10-teraazacyclododecane triacetic acid (DO3A), DEDPA (6,6’-[1,2-ethanediylbis(iminomethylene)] bis(2-pyridinecarboxylic acid) and 1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetraacetic acid (TETA),ethylenediaminetetraacetic acid (EDTA), diethylenetriamine pentaacetic acid (DTPA), CB-DO2A, 3p-C-DEPA, TCMC, DO3A, DTPA, CHX-A”-DTPA, 1B4M-DTPA, TETA, NOPO, Me-3,2-HOPO, CB-TE1A1P, CB-TE2P, MM-TE2A, DM-TE2A, sarcophagine, SarAr, SarAr-NCS, diamSar, AmBaSar, BaBaSar, TRAP, AAZTA, DATA, H2-macropa, H2dedpa, H4octapa, H4py4pa, H4Pypa, H2azapa, H5decapa, H4CHXoctapa, H4neunpa-p-Bn-NO2, CP256, PCTA, {4-[2-(bis-carboxymethylamino)-ethyl]- 7-carboxymethyl-[1,4,7]triazonan-1-yl}-acetic acid (NETA), C-NETA, C-NE3TA, HBED, HBED-CC, BCPA, CP256, YM103, desferrioxamine (DFO), H6phospa, a trithiol chelate, mercaptoacetyl, hydrazinonicotinamide, dimercaptosuccinic acid, 1,2-ethylenediylbis-L-cysteine diethyl ester, methylenediphosphonate, N, N’-bis(2-hydroxy-5-sulfobenzyl)-ethylenediamine-N, N-diacetic acid (SHBED), hexamethylpropyleneamineoxime, hexakis(methoxy isobutyl isonitrile), 2,2',2'',2'''-(1,10-dioxa-4,7,13,16-tetraazacyclooctadecane-4,7,13,16-tetrayl) tetraacetic acid (CROWN), 2-(7,13,16-tris(carboxymethyl)-1,10-dioxa-4,7,13,16-tetraazacyclooctadecan-4-yl)pentanedio ic acid (CROWNGA), H4py4pa-phenyl-NCS, PSC, bis-aminoethanethiol (BAT), TE3A, TE2A, CB-TE2A, triazacyclononane (TACN), 1,4,7-Trimethyl-1,4,7-triazacyclononane (TM-TACN), BPCA, HEHA, PEPA, H6phospha, noneunpa, or DOTAM.

[0181] In some embodiments of the peptidic compound, the radiometal chelator is TETA (1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetraacetic acid), SarAr (1-N-(4-Aminobenzyl)-3,6,10,13,16,19-hexaazabicyclo[6.6.6]-eicosane-1,8-diamine), NOTA (1,4,7-triazacyclononane-1,4,7-triacetic acid), TRAP (1,4,7-triazacyclononane-1,4,7-tris[methyl(2-carboxyethyl)phosphinic acid), HBED (N,N’-bis(2-hydroxybenzyl)-ethylenediamine-N,N’-diacetic acid), 2,3-HOPO (3-hydroxypyridin-2-one), PCTA (3,6,9,15-tetraazabicyclo[9.3.1]-pentadeca-1(15),11,13-triene-3,6,9,-triacetic acid), DFO (desferrioxamine), DTPA (diethylenetriaminepentaacetic acid), OCTAPA (N,N’-bis(6-carboxy-2-pyridylmethyl)-ethylenediamine-N,N’-diacetic acid) or another picolinic acid derivative.

[0182] In some embodiments of the peptidic compound, the radiometal chelator is DOTA, PSC (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetriacetic acid), TCMC, or CROWN. In some embodiments, the radiometal chelator is DOTA, DOTAGA, PSC, TCMC, CROWN or CROWNGA. In some embodiments, the radiometal chelator is DOTA or CROWN. In some embodiments, the radiometal chelator is DOTA, DOTAGA, CROWN, or CROWNGA.

[0183] In some embodiments of the peptidic compound, a Rradis a radiometal chelator for radiolabelling with99mTc,94mTc,186Re, or188Re, such as mercaptoacetyl, hydrazinonicotinamide, dimercaptosuccinic acid, 1,2-ethylenediylbis-L-cysteine diethyl ester,methylenediphosphonate, hexamethylpropyleneamineoxime and hexakis(methoxy isobutyl isonitrile), and the like. In some embodiments, a Rradis mercaptoacetyl, hydrazinonicotinamide, dimercaptosuccinic acid, 1,2-ethylenediylbis-L-cysteine diethyl ester, methylenediphosphonate, hexamethylpropyleneamineoxime or hexakis(methoxy isobutyl isonitrile). In some of these embodiments, the chelator is bound by a radiometal selected from99mTc,94mTc,186Re, or188Re.

[0184] In some embodiments of the peptidic compound, Rradis a chelator that can bind18F-aluminum fluoride ([18F]AlF), such as 1,4,7-triazacyclononane-1,4-diacetate (NODA) and the like. In some embodiments, the chelator is NODA. In some embodiments, the chelator is bound by [18F]AlF.

[0185] In some embodiments of the peptidic compound, Rradis a chelator that can bind72As or77As, such as a trithiol chelate and the like. In some embodiments, the chelator is a trithiol chelate. In some embodiments, the chelator is conjugated to72As. In some embodiments, the chelator is conjugated to77As.

[0186] In some embodiments, the radiometal chelator is DOTA or a derivative thereof conjugated with44Sc,47Sc,64Cu,67Cu,68Ga,86Y,90Y,111In,117mSn,149Tb,152Tb,153Sm,155Tb,161Tb,165Er,177Lu,203Pb,212Pb,212Bi,213Bi,224Ra,225Ac,227Th, or223Ra. In some embodiments, the radiometal chelator is DOTA or a derivative thereof conjugated with68Ga or177Lu. In some embodiments, the radiometal chelator is DOTAGA or a derivative thereof conjugated with44Sc,47Sc,64Cu,67Cu,68Ga,86Y,90Y,111In,117mSn,149Tb,152Tb,153Sm,155Tb,161Tb,165Er,177Lu,203Pb,212Pb,212Bi,213Bi,224Ra,225Ac,227Th, or223Ra. In some embodiments, the radiometal chelator is DOTAGA or a derivative thereof conjugated with68Ga or177Lu.

[0187] In some embodiments, the radiometal chelator is CROWN conjugated with225Ac,177Lu or68Ga. In some embodiments, the radiometal chelator is CROWNGA conjugated with225Ac,177Lu or68Ga.

[0188] In some embodiments, the radiometal chelator is TCMC conjugated with203Pb or212Pb. In some embodiments, the radiometal chelator is PSC conjugated with203Pb or212Pb.

[0189] In some embodiments, the radiometal chelator is H2-MACROPA conjugated with225Ac. In some embodiments, the radiometal chelator is Me-3,2-HOPO conjugated with227Th. In some embodiments, the radiometal chelator is H4py4pa conjugated with225Ac,227Th or177Lu. In some embodiments, the radiometal chelator is H4pypa conjugated with177Lu. In some embodiments, the radiometal chelator is NODAGA conjugated with68Ga. In some embodiments, the radiometal chelator is DTPA conjugated with111In. In some embodiments, the radiometal chelator is or DFO conjugated with89Zr.

[0190] In some embodiments, an Rradis a chelator that can bind18F-aluminum fluoride ([18F]AlF), such as 1,4,7-triazacyclononane-1,4-diacetate (NODA) and the like. In some embodiments, the chelator is NODA. In some embodiments, the chelator is bound by [18F]AlF.

[0191] In some embodiments, an Rradis a chelator that can bind72As or77As, such as a trithiol chelate and the like. In some embodiments, the chelator is a trithiol chelate. In some embodiments, the chelator is conjugated to72As. In some embodiments, the chelator is conjugated to77As.

[0192] In some embodiments, Rradn6-[linker]-RL- is DOTA-Pip-, DOTAGA-Pip-, CROWN-Pip-, or CROWNGA-Pip-.

[0193] In some embodiments of the peptidic compound, at least one Rradis a prosthetic group containing a trifluoroborate (BF3), capable of18F / 19F exchange radiolabeling. In some embodiments, Rradis BF3–R5–R4–, wherein R4is –(CH2)1-5– and wherein BF3–R5–forms: wherein R5a and R5b are each independently a C1-C5 linear or branchedalkyl group. In some embodiments, R4is –CH2–. In some embodiments, R5ais methyl. In some embodiments, R5ais ethyl. In some embodiments, R5ais propyl. In some embodiments, R5ais isopropyl. In some embodiments, R5ais butyl. In some embodiments, R5ais n-butyl. In some embodiments, R5ais pentyl. In some embodiments, R5bis methyl. In some embodiments, R5bis ethyl. In some embodiments, R5bis propyl. In some embodiments, R5bis isopropyl. In some embodiments, R5bis butyl. In some embodiments, R5bis n-butyl. In some embodiments, R5bis pentyl. In some embodiments, R5aand R5bare both methyl. In some embodiments, BF3–R5–is . In some embodiments, at least one Rrad is . In someembodiments, one fluorine in BF3is18F. In some embodiments, one, two, or three fluorines in BF3are18F. In some embodiments, all three fluorines in BF3are18F. In some embodiments, all three fluorines in BF3are19F.

[0194] In some embodiments of the peptidic compound, at least one Rradhas the structure listed in Table C or Table D. in Tables C and D, each R in –OR, –SR, –NR–, –NHR or ˗NR2is independently a C1-C5linear or branched alkyl. In some embodiments, one fluorine in BF3is18F. In some embodiments, one, two, or three fluorines in BF3are18F. In some embodiments, all three fluorines in BF3are18F. In some embodiments, all three fluorines in BF3are19F.

[0195] TABLE C: Exemplary BF3–R5– groups.

[0197] In some embodiments, a BF3–R5– may independently selected from Table C, in which each R (when present) in the pyridine substituted –OR, –SR, –NR–, –NHR or –NR2is independently a linear or branched C1-C5alkyl. In some embodiments, R is methyl. In some embodiments, R is ethyl. In some embodiments, R is propyl. In some embodiments, R is isopropyl. In some embodiments, R is n-butyl. The trifluoroborate-containing prosthetic group(s) may comprise18F. In some embodiments, one fluorine is a BF3–R5– is18F. In some embodiments, all three fluorines in a BF3–R5– are18F. In some embodiments, all three fluorines in a BF3–R5– are19F.

[0198] In some embodiments, a BF3–R5– may independently form selected from Table D, in which each R (when present) in the pyridine substituted –OR, –SR, –NR–, –NHR or –NR2is independently a linear or branched C1-C5alkyl. In some embodiments, R is methyl. In some embodiments, R is ethyl. In some embodiments, R is propyl. In some embodiments, R is isopropyl. In some embodiments, R is n-butyl. In some embodiments, a BF3–R5– is . In some embodiments, all three fluorines in a BF3–R5– are18F. In some embodiments, one fluorine in a BF3–R5– is18F. In some embodiments, all three fluorines in a BF3–R5– are19F.

[0199] In some embodiments, at least one Rradis an aryl or heteroaryl substituted with at least one radiohalogen. In some embodiments, at least one Rradis an aryl or an N-heteroaryl substituted with at least one radiohalogen. In some embodiments, at least one Rradis an aryl or a 6-membered heteroaryl substituted with at least one radiohalogen. In some embodiments, at least one Rradis a phenyl, a pyridyl, or a quinoyl substituted with at least one radiohalogen. In some embodiments, at least one Rradis a pyridyl or a quinoyl substituted with at least one radiohalogen. In some embodiments, at least one Rradis a pyridyl or a quinoyl substituted with at least one18F. In some embodiments, at least one Rradis a pyridyl or a quinoyl substituted with a18F. In some embodiments, at least one Rradis a pyridyl substituted with a18F. In some embodiments, at least one Rradis .

[0200] In some embodiments, at least one Rradis an aryl or heteroaryl substituted with at least one fluorine precursor leaving group. In some embodiments, the fluorine precursor leaving group is an electron-withdrawing leaving group. In some embodiments, the fluorine precursor leaving group is a sulfonate leaving group, aryl iodonium group, diazonium group, -NMe3+, -NO2, F, Cl, Br, I, -CN, or -CF3. In some embodiments, the fluorine precursor leaving group is a -OTs (tosylate), -OMe (mesylate), -Ons (nosylate), -NMe3+, -NO2, F, Cl, Br, I, -CN, or -CF3. In some embodiments, at least one Rradis an aryl or heteroaryl substituted with at least one -NMe3+, -NO2, F, Cl, Br, I, -CN, or -CF3. In some embodiments, at least one Rradis an aryl or an N-heteroaryl substituted with at least one -NMe3+, -NO2, F, Cl, Br, I, -CN, or -CF3. In some embodiments, at least one Rradis an aryl or a 6-membered heteroaryl substituted with at least one -NMe3+, -NO2, F, Cl, Br, I, -CN, or -CF3. In some embodiments, at least one Rradis an aryl or a pyridyl substituted with at least one -NMe3+, -NO2, F, Cl, Br, I, -CN, or -CF3. In some embodiments, at least one Rradis an aryl or a pyridyl substituted with at least one-NMe3+. In some embodiments, at least one Rradis .

[0201] In some embodiments, -Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-ψ-Xaa9-R is: D-Phe-Gln-αMeTrp-Ala-Tle-Gly-His-LeuψPro-NH2(SEQ ID NO: 3); D-Phe-Gln-αMeTrp-Ala-Val-Gly-His-Sta-Leu-NH2(SEQ ID NO: 4); D-Phe-Gln-αMeTrp-Ala-Tle-Gly-His-Sta-Leu-NH2(SEQ ID NO: 5); D-Phe-Gln-Trp-Ala-Val-N-MeGly-Trp-LeuψPro-NH2(SEQ ID NO: 6); D-Phe-Gln-αMeTrp-Ala-Tle-Gly-Trp-LeuψPro-NH2(SEQ ID NO: 7); D-Phe-Gln-αMeTrp-Ala-Tle-Gly-Trp(5-F)-LeuψPro-NH2(SEQ ID NO: 8); D-Phe-Gln-αMeTrp-Ala-Tle-Gly-Trp-Sta-Leu-NH2(SEQ ID NO: 9); D-Phe-Gln-αMeTrp-Ala-Tle-Gly-Trp(5-F)-Sta-Leu-NH2(SEQ ID NO: 10); D-Phe-Cit-αMeTrp-Ala-Tle-Gly-His-LeuψPro-NH2(SEQ ID NO: 11); D-Phe-Glu-αMeTrp-Ala-Tle-Gly-His-LeuψPro-NH2(SEQ ID NO: 12); D-Phe-Agb-αMeTrp-Ala-Tle-Gly-His-LeuψPro-NH2(SEQ ID NO: 13); D-Phe-Gln-αMeTrp-N-MeGly-Tle-Gly-His-LeuψPro-NH2(SEQ ID NO: 14); or D-Phe-Gln-αMeTrp-N-MeGly-Tle-Gly-Trp-LeuψPro-NH2(SEQ ID NO: 15), wherein ψ is a reduced peptide bond.

[0202] In some embodiments, -Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-ψ-Xaa9-Xaa10-R is D-Phe-Gln-Trp-Ala-Val-N-MeGly-His-LeuψPro-NH2(SEQ ID NO: 16).

[0203] In some embodiments, -Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-ψ-Xaa9-Xaa10-R is D-Phe-Gln-Trp-Ala-Val-N-MeGly-Trp-LeuψPro-Val-NH2(SEQ ID NO: 17); D-Phe-Gln-Trp-Ala-Val-N-MeGly-His-LeuψPro-Val-NH2(SEQ ID NO: 18); D-Phe-Gln-αMeTrp-Ala-Tle-Gly-Trp-LeuψPro-Tle-NH2(SEQ ID NO: 19); or D-Phe-Gln-αMeTrp-Ala-Tle-Gly-His-LeuψPro-Tle-NH2(SEQ ID NO: 20), wherein ψ is a reduced peptide bond.

[0204] In some embodiments, [Xaa12-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-ψ-Xaa9-R] is Pip-D-Phe-Gln-7FTrp-Ala-Tle-Gly-His-LeuψPro-NH2(SEQ ID NO: 21).

[0205] In some embodiments, the compounds of formula (A), (I), (IA), (IA-1), (IB), (IB-1), (IC), (IC-1), (ID), (ID-1), (IE), or (IE-1), excludes compounds disclosed in WO2009 / 109332. PCT application publication WO2009 / 109332 is incorporated by reference in its entirety herein.

[0206] In some embodiments, the compounds of formula (A), (I), (IA), (IA-1), (IB), (IB-1),(IC), (IC-1), (ID), (ID-1), (IE), or (IE-1), excludes compounds disclosed in WO2021 / 068051. PCT application publication WO2021 / 068051 is incorporated by reference in its entirety herein.

[0207] In some embodiments, the compounds of formula (A), (I), (IA), (IA-1), (IB), (IB-1), (IC), (IC-1), (ID), (ID-1), (IE), or (IE-1), excludes compounds described in Wang, L et al., Molecules, 202227, 3777, which is incorporated by reference in its entirety herein.

[0208] In some embodiments, the compounds of formula (A), (I), (IA), (IA-1), (IB), (IB-1), (IC), (IC-1), (ID), (ID-1), (IE), or (IE-1), excludes compounds described in Wang, L et al., Molecules, 202227, 3777, which is incorporated by reference in its entirety herein.

[0209] In some embodiments, the compounds of formula (A), (I), (IA), (IA-1), (IB), (IB-1), (IC), (IC-1), (ID), (ID-1), (IE), or (IE-1), excludes LW01186.

[0210] In some embodiments, the compounds of formula (A), (I), (IA), (IA-1), (IB), (IB-1), (IC), (IC-1), (ID), (ID-1), (IE), or (IE-1), excludes AMTG having the structure (SEQ ID NO: 66).

[0211] In some embodiments, the compounds of formula (A), (I), (IA), (IA-1), (IB), (IB-1), (IC), (IC-1), (ID), (ID-1), (IE), or (IE-1), excludes AMTG2 having the structure (SEQ ID NO: 67).

[0212] In some embodiments, the peptidic compound described herein is: (Compound 1; SEQ ID NO: 22),(Compound 2; SEQ ID NO: 23), (Compound 3; SEQ ID NO: 24), (Compound 4; SEQ ID NO: 25), or (Compound 5; SEQ ID NO: 52), or a salt or a solvate thereof. In some embodiments, the compound is conjugated by a radiometal. In some embodiments, the radiometal is68Ga,177Lu, or225Ac.

[0213] In some embodiments, the peptidic compound described herein is: (Compound 6; SEQ ID NO: 26), (Compound 7; SEQ ID NO: 47), (Compound 8; SEQ ID NO: 30), (Compound 9; SEQ ID NO: 28), (Compound 10; SEQ ID NO: 32),(Compound 11; SEQ ID NO: 49), (Compound 12; SEQ ID NO: 34), (Compound 13; SEQ ID NO: 35), (Compound 14; SEQ ID NO: 58), (Compound 15; SEQ ID NO: 51),(Compound 16; SEQ ID NO: 41), (Compound 17; SEQ ID NO: 42), or (Compound 18; SEQ ID NO: 44), or a salt or a solvate thereof. In some embodiments, the compound is conjugated by a radiometal. In some embodiments, the radiometal is68Ga,177Lu, or225Ac.

[0214] In some embodiments, the peptidic compound described herein is: (Compound 19; SEQ ID NO: 36),(Compound 20; SEQ ID NO: 37), (Compound 21; SEQ ID NO: 38), or (Compound 22; SEQ ID NO: 43), or a salt or a solvate thereof. In some embodiments, the compound is conjugated by a radiometal. In some embodiments, the radiometal is68Ga,177Lu, or225Ac.

[0215] In some embodiments, the peptidic compound described herein is: (Compound 7; SEQ ID NO: 47),(Compound 23; SEQ ID NO: 48),(Compound 11; SEQ ID NO: 49), (Compound 24; SEQ ID NO: 50), (Compound 15; SEQ ID NO: 51), (Compound 16; SEQ ID NO: 41), or (Compound 25; SEQ ID NO: 53), or a salt or a solvate thereof. In some embodiments, thecompound is conjugated by a radiometal. In some embodiments, the radiometal is68Ga,177Lu, or225Ac.

[0216] In some embodiments, the peptidic compound described herein is:(Compound 26; SEQ ID NO: 39), or(Compound 27; SEQ ID NO: 40), or a salt or a solvate thereof. In some embodiments, the compound is conjugated by a radiometal. In some embodiments, the radiometal is68Ga,177Lu, or225Ac.

[0217] In some embodiments, the peptidic compound described herein is: (Compound 28; SEQ ID NO: 59) or (Compound 29; SEQ ID NO: 46), or a salt or a solvate thereof. In some embodiments, the compound is conjugated by a radiometal. In some embodiments, the compound is conjugated with203Pb or212Pb.

[0218] In some embodiments, the peptidic compound described herein is: (Compound 30; SEQ ID NO: 60), or a salt or a solvate thereof. In some embodiments, at least one fluorine in -BF3¯ is18F. In some embodiments, one or more fluorines in -BF3¯ is18F. In some embodiments, all fluorines in -BF3¯ is18F.

[0219] In some embodiments, the peptidic compound described herein is: (Compound 31; SEQ ID NO: 61), or a salt or a solvate thereof.

[0220] In some embodiments, the peptidic compound described herein is: (Compound 32; SEQ ID NO: 62), or a salt or a solvate thereof. In some embodiments, the fluorine (substituted on pyridine) is18F.

[0221] In some embodiments, the peptidic compound described herein is: (Compound 33; SEQ ID NO: 63) or a salt or a solvate thereof.

[0222] In some embodiments, the peptidic compound described herein is: (Compound 34; SEQ ID NO: 64) or (Compound 35; SEQ ID NO: 65), or a salt or a solvate thereof. In some embodiments, the compound is conjugated by a radiometal. In some embodiments, the radiometal is68Ga,177Lu, or225Ac.

[0223] In some embodiments, the peptidic compound described herein is: (Compound 36; SEQ ID NOs: 54 and 55) or(Compound 37; SEQ ID NOs: 56 and 57), or a salt or a solvate thereof. In some embodiments, the compound is conjugated by a radiometal. In some embodiments, the radiometal is68Ga, 177Lu, or225Ac.

[0224] In some embodiments, the peptidic compound described herein is selected from any one of Compounds 1-37 (including Compounds 6A, 8A, 9A, and 10A).

[0225] In some embodiments, the peptidic compound is DOTA-Pip-D-Phe-Gln-αMeTrp-Ala-Tle-Gly-His-LeuψPro-NH2(SEQ ID NO: 22); CROWN-Pip-D-Phe-Gln-αMeTrp-Ala-Tle-Gly-His-LeuψPro-NH2(SEQ ID NO: 23); CROWN-Pip-D-Phe-Gln-αMeTrp-Ala-Val-Gly-His-Sta-Leu-NH2(SEQ ID NO: 24); CROWN-Pip-D-Phe-Gln-αMeTrp-Ala-Tle-Gly-His-Sta-Leu-NH2(SEQ ID NO: 25); DOTA-Pip-D-Phe-Gln-Trp-Ala-Val-N-MeGly-Trp-LeuψPro-NH2(SEQ ID NO: 26); DOTAGA-Pip-D-Phe-Gln-Trp-Ala-Val-N-MeGly-Trp-LeuψPro-NH2(SEQ ID NO: 27); DOTA-Pip-D-Phe-Gln-αMeTrp-Ala-Tle-Gly-Trp-LeuψPro-NH2(SEQ ID NO: 28); DOTAGA-Pip-D-Phe-Gln-αMeTrp-Ala-Tle-Gly-Trp-LeuψPro-NH2(SEQ ID NO: 29); CROWN-Pip-D-Phe-Gln-αMeTrp-Ala-Tle-Gly-Trp-LeuψPro-NH2(SEQ ID NO: 30); CROWNGA-Pip-D-Phe-Gln-αMeTrp-Ala-Tle-Gly-Trp-LeuψPro-NH2(SEQ ID NO: 31); DOTA-Pip-D-Phe-Gln-αMeTrp-Ala-Tle-Gly-Trp(5-F)-LeuψPro-NH2(SEQ ID NO: 32); DOTAGA-Pip-D-Phe-Gln-αMeTrp-Ala-Tle-Gly-Trp(5-F)-LeuψPro-NH2(SEQ ID NO: 33); CROWN-Pip-D-Phe-Gln-αMeTrp-Ala-Tle-Gly-Trp-Sta-Leu-NH2(SEQ ID NO: 34); CROWN-Pip-D-Phe-Gln-αMeTrp-Ala-Tle-Gly-Trp(5-F)-Sta-Leu-NH2(SEQ ID NO: 35); CROWN-Pip-D-Phe-Cit-αMeTrp-Ala-Tle-Gly-His-LeuψPro-NH2(SEQ ID NO: 36); CROWN-Pip-D-Phe-Glu-αMeTrp-Ala-Tle-Gly-His-LeuψPro-NH2(SEQ ID NO: 37); CROWN-Pip-D-Phe-Agb-αMeTrp-Ala-Tle-Gly-His-LeuψPro-NH2(SEQ ID NO: 38); CROWN-Pip-D-Phe-Gln-αMeTrp-Ala-Tle-Gly-Trp-(cis-4-OCy-D-Pro)-NH2(SEQ ID NO: 39); CROWN-Pip-D-Phe-Gln-αMeTrp-Ala-Tle-Gly-Trp-(cis-4-NHCy-D-Pro)-NH2(SEQ ID NO: 40); DOTA-Pip-D-Phe-Gln-αMeTrp-Ala-Tle-Gly-5FTrp-LeuψPro-Tle-NH2(SEQ ID NO: 41); DOTA-Pip-D-Phe-Cit-αMeTrp-Ala-Tle-Gly-(3-Quin-Ala)-LeuψPro-NH2(SEQ ID NO: 42); DOTA-Pip-D-Phe-Cit-αMeTrp-Ala-Val-Gly-His-Sta-Leu-NH2(SEQ ID NO: 43); orDOTA-Pip-D-Phe-Cit-αMeTrp-Ala-Val-Gly-5FTrp-Sta-Leu-NH2(SEQ ID NO: 44); wherein ψ is a reduced peptide bond. In some embodiments, the compound is conjugated by a radiometal. In some embodiments, the radiometal is68Ga,177Lu, or225Ac.

[0226] In some embodiments, the peptidic compound is TCMC-Pip-D-Phe-Gln-Trp-Ala-Val-N-MeGly-His-LeuψPro-NH2 (SEQ ID NO: 45) or PSC-Pip-D-Phe-Gln-Trp-Ala-Val-N-MeGly-His-LeuψPro-NH2 (SEQ ID NO: 46), wherein ψ is a reduced peptide bond. In some embodiments, the compound is conjugated by a radiometal. In some embodiments, the radiometal is68Ga,177Lu,203Pb,212Pb, or225Ac. In some embodiments, the radiometal is203Pb or212Pb.

[0227] In some embodiments, the peptidic compound is DOTA-Pip-D-Phe-Gln-Trp-Ala-Val-N-MeGly-Trp-LeuψPro-Val-NH2(SEQ ID NO: 47); DOTA-Pip-D-Phe-Gln-Trp-Ala-Val-N-MeGly-His-LeuψPro-Val-NH2(SEQ ID NO: 48); CROWN-Pip-D-Phe-Gln-αMeTrp-Ala-Tle-Gly-Trp-LeuψPro-Tle-NH2(SEQ ID NO: 49); or CROWN-Pip-D-Phe-Gln-αMeTrp-Ala-Tle-Gly-His-LeuψPro-Tle-NH2(SEQ ID NO: 50); CROWN -Pip-D-Phe-Cit-αMeTrp-Ala-Tle-Gly-(3-Quin-Ala)-LeuψPro-Tle-NH2(SEQ ID NO: 51); DOTAGA-Pip-D-Phe-Gln-αMeTrp-Ala-Tle-Gly-His-LeuψPro-NH2(SEQ ID NO: 52); or DOTA-Pip-D-Phe-Gln-αMeTrp-Ala-Tle-Gly-His-LeuψPro-Tle-NH2(SEQ ID NO: 53); wherein ψ is a reduced peptide bond. In some embodiments, the compound is conjugated by a radiometal. In some embodiments, the radiometal is68Ga,177Lu, or225Ac.

[0228] In some embodiments, the peptidic compound is DOTA-Glu(Pip-DPhe-Gln-7FTrp-Ala-Tle-Gly-His-LeuψPro-NH2)2(SEQ ID NOs: 54 and 55) or CROWN-Aad-Aad-Glu(Pip-DPhe-Gln-αMeTrp-Ala-Tle-Gly-His-LeuψPro-NH2)2(SEQ ID NOs: 56 and 57), wherein ψ is a reduced peptide bond. In some embodiments, the compound is conjugated by a radiometal. In some embodiments, the radiometal is68Ga,177Lu, or225Ac.

[0229] In some embodiments of the peptidic compound described herein (e.g., compounds of formula (A), (I), (IA), (IA-1), (IB), (IB-1), (IC), (IC-1), (ID), (ID-1), (IE), (IE-1), (IF), (IF-1), (II), (IIA), (B), or (B-1) or salt or solvate thereof), the compound is bound to (or conjugated with) or include a radiometal, a radiohalogen, or a radiohalogen containing metal. In some embodiments, the radiometal, the radiohalogen, or the radiohalogen containing metal is [18F]AlF,44Sc,47Sc,61Cu,64Cu,67Cu,67Ga,68Ga,72As,77As,86Y,89Zr,90Y,90Nb,94mTc,99mTc,105Rh,109Pd,110mIn,111In,114mIn,117mSn,123I,124I,131I,132La,133La,134La,134Ce,135La,142Pr,149Tb,149Pm,152Tb,153Sm,155Tb,159Gd,161Tb,165Er,166Ho,175Yb,177Lu,186Re,188Re,198Au,199Au,203Pb,211At,212Pb,212Bi,213Bi,223Ra,224Ra,225Ac, or227Th.. In some embodiments, the radiometal, the radiohalogen, or the radiohalogen containing metal is [18F]AlF,44Sc,61Cu,64Cu,67Ga,68Ga,72As,86Y,89Zr,90Nb,99mTc,110mIn,111In,123I,124I,131I,152Tb,155Tb,177Lu,203Pb,212Pb, or225Ac. In some embodiments, the radiometal is47Sc,64Cu,67Cu,77As,90Y,105Rh,109Pd,111In,117mSn,142Pr,149Pm,149Tb,153Sm,159Gd,161Tb,165Er,166Ho,175Yb,177Lu,186Re,188Re,198Au,199Au,211At,212Pb,212Bi,213Bi,223Ra,224Ra,225Ac, or227Th. In some embodiments, the radiometal is44Sc,47Sc,64Cu,67Ga,67Cu,68Ga,86Y,90Y,111In,117mSn,149Tb,152Tb,153Sm,155Tb,161Tb,165Er,177Lu,203Pb,212Pb,212Bi,213Bi,223Ra,224Ra,225Ac, or227Th. In some embodiments, the radiometal is44Sc,61Cu,64Cu,67Cu,67Ga,68Ga,86Y,90Y,111In,177Lu,213Bi,212Bi, or225Ac. In some embodiments, the radiometal is68Ga,177Lu,203Pb,212Pb, or225Ac. In some embodiments, the radiometal is68Ga,177Lu, or225Ac.

[0230] In some embodiments, the peptidic compounds described herein are gastrin-releasing peptide receptor (GRPR) antagonists.

[0231] In some embodiments, the peptidic compounds described herein the compound is conjugated with a radiometal, a radiohalogen, or a radiohalogen for positron emission tomography (PET) or single photon emission computed tomography (SPECT) imaging of GRPR expressing tumors, wherein the compound is conjugated with a radiometal, a radiohalogen, or a radiohalogen that is a positron emitter or a gamma emitter. In some embodiments, the positron or gamma emitter is18F,44Sc,61Cu,64Cu,67Ga,68Ga,72As,86Y,89Zr,90Nb,99mTc,110mIn,111In,123I,124I,131I,132La,133La,134La,134Ce,152Tb,155Tb, or203Pb.

[0232] In some embodiments, the peptidic compounds described herein the compound is conjugated with a radiometal that is used for therapy. In some embodiments, the radiometal is47Sc,64Cu,67Cu,77As,90Y,105Rh,109Pd,111In,117mSn,135La,142Pr,149Pm,149Tb,153Sm,159Gd,161Tb,165Er,166Ho,175Yb,177Lu,186Re,188Re,198Au,199Au,211At,212Pb,212Bi,213Bi,223Ra,224Ra,225Ac, or227Th.

[0233] The peptidic compounds described herein can be prepared by known peptide synthesis methods, such as methods employing 9-fluorenylmethoxycarbonyl (Fmoc) and / or t-butyloxycarbonyl (Boc) protecting groups. In some embodiments, peptide synthesis is solid-phase peptide synthesis. Fmoc protecting groups can be removed from the amino acid on the solid support under basic conditions. The amino acid to be added can be activated for coupling using activating reagents such as 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HBTU), 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (TBTU), 2-(7-Aza-1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HATU), benzotriazole-1-yl-oxy-tris(dimethylamino)phosphoniumhexafluorophosphate (BOP), benzotriazole-1-yl-oxy-tris(pyrrolidino)phosphoniumhexafluorophosphate (PyBOP). Racemization is minimized by using triazoles, such as 1-hydroxy-benzotriazole (HOBt) and 1-hydroxy-7-aza-benzotriazole (HOAt). In some embodiments, the amino acid coupling reaction is performed in the presence of a suitable base to form a typical peptide bond.

[0234] Other than the formation of a typical amino acid peptide bond, amino acids can be coupled at their sidechain functional groups including carboxylic acid and amino groups.Amino acids with carboxylic acid or an amino group in their side chain can be used to form branched peptide chain. In some embodiments, an amino acid with a side chain with a carboxylic acid is Asp, D-Asp, Glu, or D-Glu. In some embodiments, an amino acid with a side chain with an amine is Lys, D-Lys, Orn, D-Orn, Dab, D-Dab, Dap, or D-Dap.

[0235] An amino acid with an azide side chain can be used to form a triazole with another amino acid or an input with an alkyne group. In some embodiments, an amino acid with a side chain with an azide is Lys(N3) or D-Lys(N3). In some embodiments, an amino acid with a side chain with an alkyne group is Pra or D-Pra.

[0236] In some embodiments of the peptidic compounds, Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated. In some embodiments, N-methylation can be achieved by directly using Fmoc-N-methylated amino acids during peptide synthesis.

[0237] In some embodiments, the radiolabeling group or the albumin binder is coupled to the peptide N-terminus while the peptide is attached to the solid support.

[0238] A prosthetic group containing a trifluoroborate, such as BF3–R5–R4– component, can be prepared according to reported procedures (Liu et al. Angew Chem Int Ed 2014 53:11876-11880; Liu et al. J Nucl Med 2015 55:1499-1505; Liu et al. Nat Protoc 2015 10:1423-1432; Kuo et al. J Nucl Med, 201960:1160-1166; each of which is incorporated by reference in its entirety).

[0239] 18F-labeling of the BF3-containing compounds via18F-19F isotope exchange reaction can be performed following reported procedures (Liu et al. Nat Protoc 2015 10:1423-1432, incorporated by reference in its entirety). Binding and Function

[0240] A person having ordinary skill in the art would appreciate that the compounds disclosed herein are bombesin derivatives and therefore function in a similar manner to bombesin. Bombesin and its derivatives are known to bind to GRPR by inserting their C-termini into the binding pocket of the receptor (Peng, et al.2023 Proc Natl Acad Sci USA 120). Bombesin derivatives comprising a chelated radionuclide also bind to GRPR in a similar fashion while delivering a cytotoxic radiation dose to a cell (e.g., a tumor cell). A skilled person also appreciates that the disclosed compounds selectively bind to tumors that overexpress GRPR over healthy tissues and organs (e.g., pancreas and kidneys) based on the Examples disclosed herein.

[0241] In an aspect, the peptidic compounds of the invention comprise a means for binding to a GRPR-expressing tumor in a subject, wherein the peptidic compound exhibits a tumor / pancreas uptake ratio of at least 1. In some embodiments, the peptidic compound exhibits a tumor / pancreas uptake ratio of about 1.5 or higher. In some embodiments, thepeptidic compound exhibits a tumor / pancreas uptake ratio of about 2 or higher. In some embodiments, the peptidic compound exhibits a tumor / pancreas uptake ratio of about 4 or higher. In some embodiments, the peptidic compound exhibits a tumor / pancreas uptake ratio of about 5 or higher. In some embodiments, the peptidic compound exhibits a tumor / pancreas uptake ratio of about 6 or higher. In some embodiments, the peptidic compound exhibits a tumor / pancreas uptake ratio of about 7 or higher. In some embodiments, the peptidic compound exhibits a tumor / pancreas uptake ratio of about 10 or higher. In some embodiments, the peptidic compound exhibits a tumor / pancreas uptake ratio of about 16. In some embodiments, the peptidic compound comprises a radiolabeling group. In some embodiments, the radiolabeling group is a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof. In some embodiments, the peptidic compound comprises a radiometal chelator optionally comprising or complexed with a radionuclide.

[0242] In another aspect, the peptidic compounds of the invention comprise a means for binding to a GRPR-expressing tumor in a subject, wherein the peptidic compound exhibits a tumor comparative time-activity integration (AUCtumor) of at least 1000 %ID / g•h. In some embodiments, the peptidic compound exhibits an AUCtumorof at least 1100 %ID / g•h. In some embodiments, the peptidic compound exhibits an AUCtumorof at least 1200 %ID / g•h. In some embodiments, the peptidic compound exhibits an AUCtumorof at least 1300 %ID / g•h. In some embodiments, the peptidic compound exhibits an AUCtumorof at least 1400 %ID / g•h. In some embodiments, the peptidic compound exhibits an AUCtumorof at least 1500 %ID / g•h. In some embodiments, the peptidic compound exhibits an AUCtumorof at least 1600 %ID / g•h. In some embodiments, the peptidic compound exhibits an AUCtumorof at least 1700 %ID / g•h. In some embodiments, the peptidic compound exhibits an AUCtumorof at least 1800 %ID / g•h. In some embodiments, the peptidic compound exhibits an AUCtumorof at least 1900 %ID / g•h. In some embodiments, the peptidic compound exhibits an AUCtumorof at least 2000 %ID / g•h. In some embodiments, the peptidic compound exhibits an AUCtumorof at least 2100 %ID / g•h. In some embodiments, the peptidic compound comprises a radiolabeling group. In some embodiments, the radiolabeling group is a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof. In some embodiments, the peptidic compound comprises a radiometal chelator optionally comprisingor complexed with a radionuclide.

[0243] In yet another aspect, the peptidic compounds of the invention comprise a means for binding to a GRPR-expressing tumor in a subject, wherein the peptidic compound exhibits a tumor / kidney uptake ratio of at least 10. In some embodiments, the peptidic compound exhibits a tumor / kidney uptake ratio of at least 11. In some embodiments, the peptidic compound exhibits a tumor / kidney uptake ratio of at least 12. In some embodiments, the peptidic compound exhibits a tumor / kidney uptake ratio of at least 13. In some embodiments, the peptidic compound exhibits a tumor / kidney uptake ratio of at least 14. In some embodiments, the peptidic compound exhibits a tumor / kidney uptake ratio of at least 15. In some embodiments, the peptidic compound exhibits a tumor / kidney uptake ratio of at least 16. In some embodiments, the peptidic compound exhibits a tumor / kidney uptake ratio of at least 17. In some embodiments, the peptidic compound exhibits a tumor / kidney uptake ratio of at least 18. In some embodiments, the peptidic compound exhibits a tumor / kidney uptake ratio of at least 19. In some embodiments, the peptidic compound exhibits a tumor / kidney uptake ratio of at least 20. In some embodiments, the peptidic compound comprises a radiolabeling group. In some embodiments, the radiolabeling group is a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof. In some embodiments, the peptidic compound comprises a radiometal chelator optionally comprising or complexed with a radionuclide.

[0244] In an additional aspect, the peptidic compounds of the invention comprise a means for binding to a GRPR-expressing tumor in a subject, wherein the peptidic compound comprises a chelator optionally complexed with a radionuclide and wherein the peptidic compound exhibits a tumor / pancreas uptake ratio of at least 1. In some embodiments, the peptidic compound exhibits a tumor / pancreas uptake ratio of 1.5 or higher. In some embodiments, the peptidic compound exhibits a tumor / pancreas uptake ratio of 2 or higher. In some embodiments, the peptidic compound exhibits a tumor / pancreas uptake ratio of 4 or higher. In some embodiments, the peptidic compound exhibits a tumor / pancreas uptake ratio of 5 or higher. In some embodiments, the peptidic compound exhibits a tumor / pancreas uptake ratio of 6 or higher. In some embodiments, the peptidic compound exhibits a tumor / pancreas uptake ratio of about 7 or higher. In some embodiments, the peptidic compound exhibits a tumor / pancreas uptake ratio of about 10 or higher. In some embodiments, the peptidic compound exhibits a tumor / pancreas uptake ratio of about 16.

[0245] In a further aspect, the peptidic compounds of the invention comprise a means for binding to a GRPR-expressing tumor in a subject, wherein the peptidic compound comprisesa chelator optionally complexed with a radionuclide and wherein the peptidic compound exhibits a tumor comparative time-activity integration (AUCtumor) of at least 1000 %ID / g•h. In some embodiments, the peptidic compound exhibits an AUCtumorof at least 1100 %ID / g•h. In some embodiments, the peptidic compound exhibits an AUCtumorof at least 1200 %ID / g•h. In some embodiments, the peptidic compound exhibits an AUCtumorof at least 1300 %ID / g•h. In some embodiments, the peptidic compound exhibits an AUCtumorof at least 1400 %ID / g•h. In some embodiments, the peptidic compound exhibits an AUCtumorof at least 1500 %ID / g•h. In some embodiments, the peptidic compound exhibits an AUCtumorof at least 1600 %ID / g•h. In some embodiments, the peptidic compound exhibits an AUCtumorof at least 1700 %ID / g•h. In some embodiments, the peptidic compound exhibits an AUCtumorof at least 1800 %ID / g•h. In some embodiments, the peptidic compound exhibits an AUCtumorof at least 1900 %ID / g•h. In some embodiments, the peptidic compound exhibits an AUCtumorof at least 2000 %ID / g•h. In some embodiments, the peptidic compound exhibits an AUCtumorof at least 2100 %ID / g•h.

[0246] In yet another aspect, the peptidic compounds of the invention comprise a means for binding to a GRPR-expressing tumor in a subject, wherein the peptidic compound comprises a chelator optionally complexed with a radionuclide and wherein the peptidic compound exhibits a tumor / kidney uptake ratio of at least 10. In some embodiments, In some embodiments, the peptidic compound exhibits a tumor / kidney uptake ratio of at least 11. In some embodiments, the peptidic compound exhibits a tumor / kidney uptake ratio of at least 12. In some embodiments, the peptidic compound exhibits a tumor / kidney uptake ratio of at least 13. In some embodiments, the peptidic compound exhibits a tumor / kidney uptake ratio of at least 14. In some embodiments, the peptidic compound exhibits a tumor / kidney uptake ratio of at least 15. In some embodiments, the peptidic compound exhibits a tumor / kidney uptake ratio of at least 16. In some embodiments, the peptidic compound exhibits a tumor / kidney uptake ratio of at least 17. In some embodiments, the peptidic compound exhibits a tumor / kidney uptake ratio of at least 18. In some embodiments, the peptidic compound exhibits a tumor / kidney uptake ratio of at least 19. In some embodiments, the peptidic compound exhibits a tumor / kidney uptake ratio of at least 20.

[0247] In an additional aspect, the peptidic compounds of the invention comprise a means for binding to a GRPR-expressing tumor in a subject, wherein the peptidic compound comprises a chelator optionally complexed with a radionuclide and wherein the peptidic compound exhibits a tumor / pancreas uptake ratio of at least 1 (e.g., at least 1.5, at least 2, at least 4, at least 5, at least 6, at least 8, at least 10) and a tumor comparative time-activity integration (AUCtumor) of at least 1000 %ID / g•h (e.g., at least 1100, at least 1200, at least 1300, at least 1400, at least 1500, at least 1600, at least 1700, at least 1800, at least 1900, or at least 2000 %ID / g•h).

[0248] In another aspect, a peptidic compound of the invention comprises a means forbinding to a GRPR-expressing tumor in a subject, wherein the peptidic compound is a compound of Formula (A), or a salt or solvate of Formula (A): Rradn6-RL-[linker]-RL-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-[ψ-Xaa9-(Xaa10)m2]m1-R (A) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is statine (Sta), Leu, D-Pro, Phe, cis-4-NHRa-D-Pro or cis-4-ORa-D-Pro, wherein Rais alkyl, cycloalkyl, or aryl; R is -NH2or -NHOH; m1 is 0 or 1; m2 is 0 or 1; when m1 is 1 and m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m1 is 1 and m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylicacid (Me2Thz), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; each RLis independently absent, –(C1-6alkyl)-, –(C1-6alkyl)-C(O)–, –C(O)–, –NH–C(O)–, or –NH–C(S)–; the linker is a linear or branched chain of n1 units of -Xaa11-, and / or –L1R1– and / or –(L1)2R1–, wherein: n1 is 1-20; each Xaa11is independently an amino acid; each R1is, independently, a linear, branched, and / or cyclic C1-20alkylenyl, alkenylenyl and / or alkynylenyl, wherein any carbon bonded to two other carbons is optionally independently replaced by N, S, or O, and carbons are optionally independently substituted with oxo, hydroxyl, sulfhydryl, -SeH, halogen, guanidino, amine, amide, urea, carboxylic acid, sulfonic acid, sulfinic acid, or phosphoric acid; L1bonds to carbon, wherein each L1is independently –S–, –N(R2)C(O)–,–C(O)N(R2)–, –NH–C(O)–NH–, –NH–C(S)–NH–, , , ,or ; and R2is H, methyl or ethyl; optionally, the linker comprises an albumin binder (Ralb), wherein the albumin binder is: -(CH2)n3-CH3wherein n3 is 8-20; -(CH2)n4-C(O)OH wherein n4 is 8-20; wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; or ;n6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated; wherein the above peptidic compound of Formula (A) exhibits a tumor / pancreas uptake ratio of at least 1 (e.g., at least 1.5 or higher, about 2 or higher, about 4 or higher, about 5 or higher, about 6 or higher, about 7 or higher, about 10 or higher, or about 16).

[0249] In an aspect, a peptidic compound of the invention comprises a means for binding to a GRPR-expressing tumor in a subject, wherein the peptidic compound is a compound of Formula (A), or a salt or solvate of Formula (A): Rradn6-RL-[linker]-RL-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-[ψ-Xaa9-(Xaa10)m2]m1-R (A) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala);Xaa8is statine (Sta), Leu, D-Pro, Phe, cis-4-NHRa-D-Pro or cis-4-ORa-D-Pro, wherein Rais alkyl, cycloalkyl, or aryl; R is -NH2or -NHOH; m1 is 0 or 1; m2 is 0 or 1; when m1 is 1 and m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m1 is 1 and m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; each RLis independently absent, –(C1-6alkyl)-, –(C1-6alkyl)-C(O)–, –C(O)–, –NH–C(O)–, or –NH–C(S)–; the linker is a linear or branched chain of n1 units of -Xaa11-, and / or –L1R1– and / or –(L1)2R1–, wherein: n1 is 1-20; each Xaa11is independently an amino acid; each R1is, independently, a linear, branched, and / or cyclic C1-20alkylenyl, alkenylenyl and / or alkynylenyl, wherein any carbon bonded to two other carbons is optionally independently replaced by N, S, or O, and carbons are optionally independently substituted with oxo, hydroxyl, sulfhydryl, -SeH, halogen, guanidino, amine, amide, urea, carboxylic acid, sulfonic acid, sulfinic acid, or phosphoric acid; L1bonds to carbon, wherein each L1is independently –S–, –N(R2)C(O)–,–C(O)N(R2)–, –NH–C(O)–NH–, –NH–C(S)–NH–, , , ,or ; and R2is H, methyl or ethyl; optionally, the linker comprises an albumin binder (Ralb), wherein the albumin binder is: -(CH2)n3-CH3wherein n3 is 8-20; -(CH2)n4-C(O)OH wherein n4 is 8-20;wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; or ; n6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated; wherein the above peptidic compound of Formula (A) exhibits a tumor comparative time-activity integration (AUCtumor) of at least 1000 %ID / g•h (e.g., at least 1100 %ID / g•h, at least 1200 %ID / g•h, at least 1300 %ID / g•h, at least 1400 %ID / g•h, at least 1500 %ID / g•h, at least 1600 %ID / g•h, at least 1700 %ID / g•h, at least 1800 %ID / g•h, at least 1900 %ID / g•h, at least 2000 %ID / g•h, or at least 2100 %ID / g•h).

[0250] In yet another aspect, a peptidic compound of the invention comprises a means for binding to a GRPR-expressing tumor in a subject, wherein the peptidic compound is a compound of Formula (A), or a salt or solvate of Formula (A): Rradn6-RL-[linker]-RL-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-[ψ-Xaa9-(Xaa10)m2]m1-R (A) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me),Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is statine (Sta), Leu, D-Pro, Phe, cis-4-NHRa-D-Pro or cis-4-ORa-D-Pro, wherein Rais alkyl, cycloalkyl, or aryl; R is -NH2or -NHOH; m1 is 0 or 1; m2 is 0 or 1; when m1 is 1 and m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m1 is 1 and m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; each RLis independently absent, –(C1-6alkyl)-, –(C1-6alkyl)-C(O)–, –C(O)–, –NH–C(O)–, or –NH–C(S)–; the linker is a linear or branched chain of n1 units of -Xaa11-, and / or –L1R1– and / or –(L1)2R1–, wherein: n1 is 1-20; each Xaa11is independently an amino acid; each R1is, independently, a linear, branched, and / or cyclic C1-20alkylenyl,alkenylenyl and / or alkynylenyl, wherein any carbon bonded to two other carbons is optionally independently replaced by N, S, or O, and carbons are optionally independently substituted with oxo, hydroxyl, sulfhydryl, -SeH, halogen, guanidino, amine, amide, urea, carboxylic acid, sulfonic acid, sulfinic acid, or phosphoric acid; L1bonds to carbon, wherein each L1is independently –S–, –N(R2)C(O)–,–C(O)N(R2)–, –NH–C(O)–NH–, –NH–C(S)–NH–, , , ,or ; and R2is H, methyl or ethyl; optionally, the linker comprises an albumin binder (Ralb), wherein the albumin binder is: -(CH2)n3-CH3wherein n3 is 8-20; -(CH2)n4-C(O)OH wherein n4 is 8-20;wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; or n6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated; wherein the above peptidic compound exhibits a tumor / pancreas uptake ratio of at least 1 (e.g., at least 1.5, at least 2, at least 4, at least 5, at least 6, at least 8, at least 10) and a tumor comparative time-activity integration (AUCtumor) of at least 1000 (e.g., at least 1100, at least 1200, at least 1300, at least 1400, at least 1500, at least 1600, atleast 1700, at least 1800, at least 1900, or at least 2000) %ID / g•h.

[0251] In another aspect, a peptidic compound of the invention comprises a means for binding to a GRPR-expressing tumor in a subject, wherein the peptidic compound is a compound of Formula (I), or a salt or solvate of Formula (I), Rradn6-[linker]-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-[ψ-Xaa9-(Xaa10)m2]m1-R (I) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 22-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I),Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; Xaa8is statine (Sta), Leu, D-Pro, Phe, cis-4-NHRa-D-Pro or cis-4-ORa-D-Pro, wherein Rais alkyl, cycloalkyl, or aryl; R is -NH2or -NHOH; m1 is 0 or 1; m2 is 0 or 1; when m1 is 1 and m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m1 is 1 and m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid(4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, Me2Thz (5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; the linker is a linear or branched chain of n1 units of -Xaa11-; n1 is 1-20; each Xaa11is independently an amino acid; optionally, the linker comprises an albumin binder (Ralb), wherein the albumin binder is: -(CH2)n3-CH3wherein n3 is 8-20; -(CH2)n4-C(O)OH wherein n4 is 8-20;wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; or ; n6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated; wherein the above peptidic compound exhibits a tumor / pancreas uptake ratio of at least 1 (e.g., at least 1.5 or higher, about 2 or higher, about 4 or higher, about 5 or higher, about 6 or higher, about 7 or higher, about 10 or higher, or about 16).

[0252] In another aspect, a peptidic compound of the invention comprises a means for binding to a GRPR-expressing tumor in a subject, wherein the peptidic compound is acompound of Formula (I), or a salt or solvate of Formula (I), Rradn6-[linker]-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-[ψ-Xaa9-(Xaa10)m2]m1-R (I) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 22-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I),Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; Xaa8is statine (Sta), Leu, D-Pro, Phe, cis-4-NHRa-D-Pro or cis-4-ORa-D-Pro, wherein Rais alkyl, cycloalkyl, or aryl; R is -NH2or -NHOH; m1 is 0 or 1; m2 is 0 or 1; when m1 is 1 and m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m1 is 1 and m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, Me2Thz (5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is-NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; the linker is a linear or branched chain of n1 units of -Xaa11-; n1 is 1-20; each Xaa11is independently an amino acid; optionally, the linker comprises an albumin binder (Ralb), wherein the albumin binder is: -(CH2)n3-CH3wherein n3 is 8-20; -(CH2)n4-C(O)OH wherein n4 is 8-20; wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl;wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; or ; n6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated; wherein the above peptidic compound exhibits a tumor comparative time-activity integration (AUCtumor) of at least 1000 %ID / g•h (e.g., at least 1100 %ID / g•h, at least 1200 %ID / g•h, at least 1300 %ID / g•h, at least 1400 %ID / g•h, at least 1500 %ID / g•h, at least 1600 %ID / g•h, at least 1700 %ID / g•h, at least 1800 %ID / g•h, at least 1900 %ID / g•h, at least 2000 %ID / g•h, or at least 2100 %ID / g•h).

[0253] In another aspect, a peptidic compound of the invention comprises a means for binding to a GRPR-expressing tumor in a subject, wherein the peptidic compound is a compound of Formula (I), or a salt or solvate of Formula (I),Rradn6-[linker]-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-[ψ-Xaa9-(Xaa10)m2]m1-R (I) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 22-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I),Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; Xaa8is statine (Sta), Leu, D-Pro, Phe, cis-4-NHRa-D-Pro or cis-4-ORa-D-Pro, wherein Rais alkyl, cycloalkyl, or aryl; R is -NH2or -NHOH; m1 is 0 or 1; m2 is 0 or 1; when m1 is 1 and m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m1 is 1 and m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, Me2Thz (5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met;ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; the linker is a linear or branched chain of n1 units of -Xaa11-; n1 is 1-20; each Xaa11is independently an amino acid; optionally, the linker comprises an albumin binder (Ralb), wherein the albumin binder is: -(CH2)n3-CH3wherein n3 is 8-20; -(CH2)n4-C(O)OH wherein n4 is 8-20; wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, andR3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; or ;n6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated; wherein the above peptidic compound exhibits a tumor / pancreas uptake ratio of at least 1 (e.g., at least 1.5, at least 2, at least 4, at least 5, at least 6, at least 8, at least 10) and a tumor comparative time-activity integration (AUCtumor) of at least 1000 (e.g., at least 1100, at least 1200, at least 1300, at least 1400, at least 1500, at least 1600, at least 1700, at least 1800, at least 1900, or at least 2000) %ID / g•h.

[0254] In yet another aspect, a peptidic compound of the invention comprises a means for binding to a GRPR-expressing tumor in a subject, wherein the peptidic compound is a compound of Formula (A), or a salt or solvate of Formula (A): Rradn6-RL-[linker]-RL-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-[ψ-Xaa9-(Xaa10)m2]m1-R(A) wherein: Xaa1is an N-terminal residue comprising any proteinogenic or nonproteinogenic amino acid; Xaa2is any proteinogenic or nonproteinogenic amino acid; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa4is any proteinogenic or nonproteinogenic amino acid; Xaa5is any proteinogenic or nonproteinogenic amino acid; Xaa6is any proteinogenic or nonproteinogenic amino acid; Xaa7is Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is any proteinogenic or nonproteinogenic amino acid; R is -NH2or -NHOH; m1 is 0 or 1; m2 is 0 or 1; when m1 is 1 and m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue; when m1 is 1 and m2 is 1, Xaa9is any proteinogenic or nonproteinogenic amino acid; and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; each RLis independently absent, –(C1-6alkyl)-, –(C1-6alkyl)-C(O)–, –C(O)–, –NH–C(O)–, or –NH–C(S)–; the linker is a linear or branched chain optionally comprising an albumin binder; n6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic groupcontaining a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated; wherein the above peptidic compound of Formula (A) exhibits a tumor / pancreas uptake ratio of at least 1 (e.g., at least 1.5 or higher, about 2 or higher, about 4 or higher, about 5 or higher, about 6 or higher, about 7 or higher, about 10 or higher, or about 16).

[0255] In an aspect, a peptidic compound of the invention comprises a means for binding to a GRPR-expressing tumor in a subject, wherein the peptidic compound is a compound of Formula (A), or a salt or solvate of Formula (A): Rradn6-RL-[linker]-RL-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-[ψ-Xaa9-(Xaa10)m2]m1-R (A) wherein: Xaa1is an N-terminal residue comprising any proteinogenic or nonproteinogenic amino acid; Xaa2is any proteinogenic or nonproteinogenic amino acid; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa4is any proteinogenic or nonproteinogenic amino acid; Xaa5is any proteinogenic or nonproteinogenic amino acid; Xaa6is any proteinogenic or nonproteinogenic amino acid; Xaa7is Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is any proteinogenic or nonproteinogenic amino acid; R is -NH2or -NHOH; m1 is 0 or 1; m2 is 0 or 1; when m1 is 1 and m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue; when m1 is 1 and m2 is 1, Xaa9is any proteinogenic or nonproteinogenic amino acid; and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminallyhydroxylamidated (R is -NHOH) amino acid residue; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; each RLis independently absent, –(C1-6alkyl)-, –(C1-6alkyl)-C(O)–, –C(O)–, –NH–C(O)–, or –NH–C(S)–; the linker is a linear or branched chain optionally comprising an albumin binder; n6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated; wherein the above peptidic compound of Formula (A) exhibits a tumor comparative time-activity integration (AUCtumor) of at least 1000 %ID / g•h (e.g., at least 1100 %ID / g•h, at least 1200 %ID / g•h, at least 1300 %ID / g•h, at least 1400 %ID / g•h, at least 1500 %ID / g•h, at least 1600 %ID / g•h, at least 1700 %ID / g•h, at least 1800 %ID / g•h, at least 1900 %ID / g•h, at least 2000 %ID / g•h, or at least 2100 %ID / g•h).

[0256] In yet another aspect, a peptidic compound of the invention comprises a means for binding to a GRPR-expressing tumor in a subject, wherein the peptidic compound is a compound of Formula (A), or a salt or solvate of Formula (A): Rradn6-RL-[linker]-RL-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-[ψ-Xaa9-(Xaa10)m2]m1-R (A) wherein: Xaa1is an N-terminal amino acid residue comprising any proteinogenic or nonproteinogenic amino acid; Xaa2is any proteinogenic or nonproteinogenic amino acid; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa4is any proteinogenic or nonproteinogenic amino acid; Xaa5is any proteinogenic or nonproteinogenic amino acid; Xaa6is any proteinogenic or nonproteinogenic amino acid; Xaa7is Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br),Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is any proteinogenic or nonproteinogenic amino acid; R is -NH2or -NHOH; m1 is 0 or 1; m2 is 0 or 1; when m1 is 1 and m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue; when m1 is 1 and m2 is 1, Xaa9is any proteinogenic or nonproteinogenic amino acid; and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; each RLis independently absent, –(C1-6alkyl)-, –(C1-6alkyl)-C(O)–, –C(O)–, –NH–C(O)–, or –NH–C(S)–; the linker is a linear or branched chain optionally comprising an albumin binder; n6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated; wherein the above peptidic compound exhibits a tumor / pancreas uptake ratio of at least 1 (e.g., at least 1.5, at least 2, at least 4, at least 5, at least 6, at least 8, at least 10) and a tumor comparative time-activity integration (AUCtumor) of at least 1000 (e.g., at least 1100, at least 1200, at least 1300, at least 1400, at least 1500, at least 1600, at least 1700, at least 1800, at least 1900, or at least 2000) %ID / g•h.

[0257] In another aspect, a peptidic compound of the invention comprises a means for binding to a GRPR-expressing tumor in a subject, wherein the peptidic compound is a compound of Formula (I), or a salt or solvate of Formula (I), Rradn6-[linker]-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-[ψ-Xaa9-(Xaa10)m2]m1-R (I) wherein: Xaa1is an N-terminal amino acid residue comprising any proteinogenic or nonproteinogenic amino acid; Xaa2is any proteinogenic or nonproteinogenic amino acid;Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; Xaa4is any proteinogenic or nonproteinogenic amino acid; Xaa5is any proteinogenic or nonproteinogenic amino acid; Xaa6is any proteinogenic or nonproteinogenic amino acid; Xaa7is Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I),Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; Xaa8is any proteinogenic or nonproteinogenic amino acid; R is -NH2or -NHOH; m1 is 0 or 1; m2 is 0 or 1; when m1 is 1 and m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue; when m1 is 1 and m2 is 1, Xaa9is any proteinogenic or nonproteinogenic amino acid; and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; the linker is a linear or branched chain optionally comprising an albumin binder; n6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated; wherein the above peptidic compound exhibits a tumor / pancreas uptake ratio of at least 1 (e.g., at least 1.5 or higher, about 2 or higher, about 4 or higher, about 5 or higher, about 6 or higher, about 7 or higher, about 10 or higher, or about 16).

[0258] In another aspect, a peptidic compound of the invention comprises a means for binding to a GRPR-expressing tumor in a subject, wherein the peptidic compound is a compound of Formula (I), or a salt or solvate of Formula (I),Rradn6-[linker]-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-[ψ-Xaa9-(Xaa10)m2]m1-R (I) wherein: Xaa1is an N-terminal amino acid residue comprising any proteinogenic or nonproteinogenic amino acid; Xaa2is any proteinogenic or nonproteinogenic amino acid; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; Xaa4is any proteinogenic or nonproteinogenic amino acid; Xaa5is any proteinogenic or nonproteinogenic amino acid; Xaa6is any proteinogenic or nonproteinogenic amino acid; Xaa7is Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I),Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; Xaa8is any proteinogenic or nonproteinogenic amino acid; R is -NH2or -NHOH; m1 is 0 or 1; m2 is 0 or 1; when m1 is 1 and m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue; when m1 is 1 and m2 is 1, Xaa9is any proteinogenic or nonproteinogenic amino acid; and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; the linker is a linear or branched chain optionally comprising an albumin linker; n6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is eachoptionally N-methylated; wherein the above peptidic compound exhibits a tumor comparative time-activity integration (AUCtumor) of at least 1000 %ID / g•h (e.g., at least 1100 %ID / g•h, at least 1200 %ID / g•h, at least 1300 %ID / g•h, at least 1400 %ID / g•h, at least 1500 %ID / g•h, at least 1600 %ID / g•h, at least 1700 %ID / g•h, at least 1800 %ID / g•h, at least 1900 %ID / g•h, at least 2000 %ID / g•h, or at least 2100 %ID / g•h).

[0259] In another aspect, a peptidic compound of the invention comprises a means for binding to a GRPR-expressing tumor in a subject, wherein the peptidic compound is a compound of Formula (I), or a salt or solvate of Formula (I), Rradn6-[linker]-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-[ψ-Xaa9-(Xaa10)m2]m1-R (I) wherein: Xaa1is an N-terminal amino acid residue comprising any proteinogenic or nonproteinogenic amino acid; Xaa2is any proteinogenic or nonproteinogenic amino acid; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; Xaa4is any proteinogenic or nonproteinogenic amino acid; Xaa5is any proteinogenic or nonproteinogenic amino acid; Xaa6is any proteinogenic or nonproteinogenic amino acid; Xaa7is Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I),Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; Xaa8is any proteinogenic or nonproteinogenic amino acid; R is -NH2or -NHOH; m1 is 0 or 1; m2 is 0 or 1; when m1 is 1 and m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue; when m1 is 1 and m2 is 1, Xaa9is any proteinogenic or nonproteinogenic amino acid; and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9;the linker is a linear or branched chain optionally comprising an albumin binder; n6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated; wherein the above peptidic compound exhibits a tumor / pancreas uptake ratio of at least 1 (e.g., at least 1.5, at least 2, at least 4, at least 5, at least 6, at least 8, at least 10) and a tumor comparative time-activity integration (AUCtumor) of at least 1000 (e.g., at least 1100, at least 1200, at least 1300, at least 1400, at least 1500, at least 1600, at least 1700, at least 1800, at least 1900, or at least 2000) %ID / g•h.

[0260] In some embodiments, the means for binding to a GRPR-expressing tumor in a subject is achieved by a portion of the peptidic compound having any one of SEQ ID NOs: 3-21. In some embodiments, the means for binding to a GRPR-expressing tumor in a subject is achieved by a peptidic compound having SEQ ID NO: 2. In some embodiments, the means for binding to a GRPR-expressing tumor in a subject is achieved by a peptidic compound having any one of SEQ ID NOs: 22-65. Compositions

[0261] In another aspect, a composition comprising any one of the peptidic compounds as described herein is disclosed. In some embodiments, the composition is a pharmaceutical composition. In some embodiments, the composition comprises a pharmaceutically acceptable excipient or carrier.

[0262] The GRPR targeting compounds disclosed herein are typically formulated for administration to a patient, either before or after incorporation of a radiolabel. Certain embodiments of the invention thus relate to pharmaceutical compositions comprising one or more of the radio-labelled GRPR targeting compounds, or unlabeled GRPR targeting compounds, and a pharmaceutically acceptable carrier, diluent, or excipient. The pharmaceutical compositions are prepared by known procedures using well-known and readily available ingredients.

[0263] The pharmaceutical compositions comprising the GRPR targeting compounds are typically formulated for parenteral administration. The term parenteral as used herein includes subcutaneous, intradermal, intra-articular, intravenous, intraperitoneal, intramuscular, intravascular, intrasternal, intrathecal injection or infusion techniques.

[0264] In certain embodiments, the pharmaceutical compositions may be in the formof a sterile injectable aqueous or oleaginous suspension. This suspension may be formulated according to known art using those suitable dispersing or wetting agents and suspending agents that have been mentioned above. The sterile injectable preparation may also be a sterile injectable solution or a suspension in a non-toxic parentally acceptable diluent or solvent, for example as a solution in 1,3-butanediol. Among the acceptable vehicles and solvents that may be employed are water, Ringer's solution and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium. For this purpose, any bland fixed oil may be employed including synthetic mono- or diglycerides. In addition, fatty acids such as oleic acid find use in the preparation of injectables. Adjuvants such as local anesthetics, preservatives and buffering agents can also be included in the injectable solution or suspension.

[0265] Other pharmaceutical compositions and methods of preparing pharmaceutical compositions are known in the art and are described, for example, in “Remington: The Science and Practice of Pharmacy” (formerly “Remingtons Pharmaceutical Sciences”); Gennaro, A., Lippincott, Williams & Wilkins, Philadelphia, PA (2000). Diagnostic Applications

[0266] In a further aspect, this disclosure relates to diagnostic applications of the radio-labelled GRPR targeting compounds for imaging a cancer or tissue in which GRPR is expressed, aberrantly expressed, ectopically expressed, or overexpressed, for example, in oncology.

[0267] Overexpression of GRPR has been demonstrated in many malignancies, including psychiatric disorder, neurological disorder, inflammatory disease, prostate cancer, lung cancer, head and neck cancer, colon cancer, kidney cancer, ovarian cancer, liver cancer, pancreatic cancer, breast cancer, glioma (e.g., glioblastoma), or neuroblastoma. GRPR activation has been shown to potentiate malignant behaviors by inducing cell proliferation, migration, and angiogenesis. Certain embodiments of the invention thus contemplate that the radio-labelled GRPR targeting compounds could be used as imaging probes for cancers of prostate cancer, lung cancer, head and neck cancer, colon cancer, kidney cancer, ovarian cancer, liver cancer, pancreatic cancer, breast cancer, glioma (e.g., glioblastoma), or neuroblastoma, including for use in early diagnosis of solid malignancies that express GRPR, as imaging agents to confirm the diagnostic of malignancy, or to guide focal ablative treatment if the disease is localized. According to certain embodiments, the GRPR targeting compounds could also be used to monitor response to therapy, by providing an independent assessment of the residual cellular content of a tumor known to overexpress GRPR.

[0268] Radio-labelled GRPR targeting compounds of this disclosure can show high contrast, rapid renal clearance, minimal non-target organ uptake, and high tumour to normaltissue ratios, which properties make these compounds well-suited for use as imaging agents for cancer diagnosis, including diagnosis of early-stage cancer. In particular, certain GRPR targeting compounds according to embodiments of the invention exhibit relatively low renal retention, and relatively high ratio of tumor:kidney and / or tumor / pancreas uptake, facilitating safe and effective use of the compounds in diagnostic and radiotherapeutic treatments.

[0269] In some embodiments of the invention, it is contemplated that the radio-labelled GRPR targeting compounds may be used as PET / SPECT imaging probes to assist with precise localization of primary or recurrent cancer in order to guide and assist with focal ablative therapies.

[0270] In some embodiments, the invention contemplates that the radio-labelled GRPR targeting compounds could be used to monitor response to therapy, by providing an independent assessment of the residual cellular content of a tumour known to overexpress GRPR. Overexpression of GRPR may be an indicator of angiogenesis in tumours, as blocking of GRPR activation is known to have antiangiogenic activity.

[0271] There is some evidence that GRPR antagonists might cause growth inhibition in some cancers. In certain embodiments, GRPR expression and receptor blockage could be detected by imaging with the radio-labelled GRPR targeting compounds, which could then act as a predictive biomarker for treatment success.

[0102] In some embodiments, the use of the radio-labelled GRPR targeting compounds in multimodality imaging of cancers is contemplated, for example, combined functional imaging and anatomical imaging, such as PET / CT or SPECT / CT. Multimodality imaging may be useful in situations in which a cancer is present, but the uptake of imaging agent is low. Therapeutic Uses

[0272] In an additional aspect, the present disclosure provides a method for treating a disease or condition. In some embodiments, the disease or the condition is a GRPR-expressing condition or disease.

[0273] In an additional aspect, the present disclosure provides a method for treating a GRPR-expressing condition or disease comprises administering to a subject in need of imaging any one of the peptidic compounds or compositions comprising any one of the peptidic compounds disclosed herein. In some embodiments, the GRPR-expressing condition or disease is cancer. In some embodiments, the GRPR-expressing condition or disease is a psychiatric disorder, neurological disorder, inflammatory disease, prostate cancer, lung cancer, head and neck cancer, colon cancer, kidney cancer, ovarian cancer, liver cancer, pancreatic cancer, breast cancer, glioma (e.g., glioblastoma), or neuroblastoma. In some embodiments, the cancer is prostate cancer. In some embodiments, the cancer is breast cancer. In some embodiments, the cancer is glioblastoma. According to furtherembodiments, the GRPR targeting compounds can be used for endoradiotherapy targeting cells expressing GRPR, by radiolabelling the compound with a radioisotope, usually a β- or α-particle emitter, to deliver a high local dose of radiation to lesions, to inflict DNA damage and inducing cellular death. Unlike external beam radiation therapy, in certain embodiments this systemic treatment can be effective even in the treatment of metastases. Pharmaceutical Packs or Kits

[0274] Certain embodiments of the invention relate to pharmaceutical packs or kits containing one or more GRPR targeting compounds, for example, therapeutic or diagnostic packs or kits. The compounds may be provided radio-labelled or as precursors suitable for radio-labelling, in which case the kit may optionally include additional reagents for radio-labelling the compounds.

[0275] In certain embodiments, one or more of the components of the kit can be lyophilized and the kit can additionally contain a suitable solvent for reconstitution of the lyophilized components. Individual components of the kit would typically be packaged in separate containers and, associated with such containers, can be a notice in the form prescribed by a governmental agency regulating the manufacture, use or sale of pharmaceuticals or biological products, which notice reflects approval by the agency of manufacture, for use or sale for human or animal administration.

[0276] In certain embodiments, the compound(s) are provided in the kit in the form of pharmaceutical compositions suitable for administration to a subject. In this case, if desired, the container may itself be an inhalant, syringe, pipette, eye dropper, or other such like apparatus, from which the composition may be administered to the subject.

[0277] GRPR targeting compounds described herein can be synthesized according to conventional methods known to those of ordinary skill in the art. Exemplary, non-limiting procedures are provided in the Examples below.

[0278] It is contemplated that any embodiment discussed herein can be implemented with respect to any method, use or composition of the invention, and vice versa. Furthermore, compositions and kits of the invention can be used to achieve methods and uses of the invention.

[0279] To gain a better understanding of the invention described herein, the following examples are set forth. It will be understood that these examples are intended to describe illustrative embodiments of the invention and are not intended to limit the scope of the invention in any way.EXAMPLES

[0280] General methods

[0281] Chemicals were procured from commercial sources and used without further purification. All peptides were synthesized on a peptide synthesizer (Liberty Blue 2.0). Purification and quality control of peptide precursor and nonradioactive Lu-complexed and La-complexed standards were performed on Agilent HPLC and LC / MS systems. HPLC columns used were preparative columns (Luna 5 μm C18(2) 100 Å, LC Column 150 x 21.2 mm), (Luna 5 μm C18(2) 100 Å, LC Column 50 x 30 mm), semipreparative columns (Luna C18, 5 µm particle size, 100 Å pore size, 250 × 10 mm), (Aeris 3.6 μm PEPTIDE XB-C18100 Å, LC Column 250 x 4.6 mm) and analytical columns (Luna C18, 5 µm particle size, 100 Å pore size, 250 × 4.6 mm), (Kinetex 2.6 μm PS C18100 Å, LC Column 100 x 3 mm) and (Kinetex 2.6 μm C18100 Å, LC Column 100 x 3 mm) from Phenomenex. The collected HPLC eluates containing the desired peptides were lyophilized using a Labconco FreeZone 4.5 Plus freeze drier. Mass analyses were performed using Agilent mass spectrometer.

[0282] General Peptide Synthesis:

[0283] At a 0.1 mmol scale, Sieber resin or Rink Amide Resin was deprotected by treating the resin with 20% piperidine in DMF (3 × 8 min). Fmoc-Leu-ψ-Pro-OH (or the first amino acid) was coupled to the resin via solid-phase peptide synthesis using Fmoc-based chemistry. The coupling was carried out in DMF using Fmoc-Leu-ψ-Pro-OH (4 eq.), HATU (4 eq.), HOAt (4 eq.) and DIEPA (11 eq.) at room temperature for overnight (16 hours). The preloaded Fmoc-Leu-ψ-Pro-Sieber resin (or Rink Amide resin) was then loaded onto the Liberty Blue, and the Fmoc was deprotected with 10% Piperidine in DMF at 45°C (3 min x 3) or 20% piperidine in DMF at room temperature (3 × 8 min). According to the peptide sequence, each Fmoc-protected amino acid (4 eq., 0.4 mmol, 0.2 M in DMF) was subsequently coupled at 45°C (20 min) using 1 M DIC / 1 M Oxyma in DMF or coupled at room temperature (1-3h) using HATU (4 eq.), HOAt (4 eq.) in DMF, followed by Fmoc-deprotection as described above. Fmoc-Ala-OH was double-coupled at 45°C (20 min x 2) or room temperature (1h x 2). The synthesis continued with the addition of the linker, Fmoc-4-amino-(1-carboxymethyl) piperidine (4 eq.), using double coupling at 45°C for 1.5 h or couple at room temperature for 3 h and then followed by the chelator DOTA(tBu)3(4 eq) or Crown(tBu)3(4 eq) at 25°C for 18h. The coupling of the linker and the chelator were carried out using HATU / HOAt / DIPEA(4 / 4 / 11 eq). The peptide was then deprotected and simultaneously cleaved from the resin by treating with 95 / 5 trifluoroacetic acid (TFA) / triisopropylsilane (TIS) for 2 h at room temperature. After filtration, the crude peptide was precipitated by the addition of cold diethyl ether to the TFA solution and lyophilized in a H2O / MeCN mixture.

[0284] Cold Lutetium or Lanthanum cold complexations synthesis:

[0285] The precursor (1 eq., 5-10 mg) and LuCl3(5 eq.) or LaCl3(5 eq.) were dissolved in0.1 M aq. NaOAc and MeCN (2.5:1, DMSO was added when solubility is low). The reaction mixture was heated to 90°C for 30 minutes, at which point most reactions were complete (monitored by MS). The reaction mixture was then diluted with H2O / MeCN and directly purified by semi-prep HPLC (0.1% TFA in H2O / MeCN) to afford the Lu or La-cold standard. Isolated amounts ranged from 3-8 mg, and purities (HPLC) were between 95% and 99%.

[0286] General methods of radiolabeling with177Lu:

[0287] Generally, a small aliquot of the precursor (1-5 µL, 1-3 nmol) was dissolved in the reaction buffer / solution with a known pH. To the solution was added a known amount / activity of177LuCl3. Then, the reaction was heated to 85°C for 20-30 minutes. At this point, the reaction was cooled down and further diluted with the suitable formulation or dilution buffer. For analysis, the reaction mixtures and / or diluted solutions were analyzed using radio-TLC (iTLC) and radio-HPLC. Generally, iTLCs were run on SG paper plates, with 0.1 M sodium citrate as the eluent and other optional solvents as needed. The developed plates were then read using a radio-TLC reading instrument. HPLC analyses were performed using a suitable C18 column, with different combinations of H2O and MeCN (both with 0.1% TFA) as the eluent. The eluting components were visualized by UV (DAD) and radio-detection flow monitors. In all cases, the radiochemical purity of the radiolabeled compound was assessed at the end of synthesis (EOS) and after 3 h (estimated time between end of synthesis and in vivo experiments).

[0288] General methods of radiolabeling with225Ac:

[0289] Generally, a small aliquot of the precursor (1-10 µL, 1-10 nmol) was dissolved in the reaction buffer / solution with a known pH. To the solution was added a known amount / activity of225AcCl3or225Ac(NO3)3Then, the reaction was heated to 95°C for 15-30 minutes. At this point, the reaction was cooled down and further diluted with the suitable formulation or dilution buffer. For analysis, the reaction mixtures and / or diluted solutions were analyzed using radio-TLC (iTLC) and radio-HPLC. Generally, iTLCs were run on SG paper plates, with 0.1 M sodium citrate as the eluent and other optional solvents as needed. The developed plates were then read using a radio-TLC reading instrument. HPLC analyses were performed using a suitable C18 column, with different combinations of H2O and MeCN (both with 0.1% TFA) as the eluent. The eluting components were visualized by UV (DAD) and radio-detection flow monitors. To detect the emissions resulting from the decay chain of225Ac, all collected fractions from HPLC were allowed to equilibrate for 6 h, then were placed in a Gamma counting instrument for subsequent measurements. In all cases, the radiochemical purity of the radiolabeled compound was assessed at the end of synthesis (EOS) and after 3-5 h (estimated time between end of synthesis and in vivo experiments).

[0290] Example 1: Synthesis

[0291] Synthesis of Compound 1

[0292] Sieber resin was deprotected by treating the resin with 20% piperidine in DMF (3 × 8 min). Fmoc-Leu-ψ-Pro-OH was coupled to the resin via solid-phase peptide synthesis using Fmoc-based chemistry. The coupling was carried out in DMF using Fmoc-Leu-ψ-Pro-OH (4 eq.), HATU (4 eq.), HOAt (4 eq.) and DIEPA (11 eq.) at room temperature for overnight (16 hours). At a 0.15 mmol scale, the preloaded Fmoc-Leu-ψ-Pro-Sieber resin was then loaded onto the peptide synthesizer, and the Fmoc was deprotected with 10% Piperidine in DMF at 45°C (3 min x 3). Then, Fmoc-His(Boc)-OH (4 eq., 0.4 mmol, 0.2 M in DMF) was coupled at 45°C (10 min) using 1 M DIC / 1 M Oxyma in DMF (1 mL / 0.5 mL), followed by Fmoc-deprotection as described above. Fmoc-Gly-OH, Fmoc-Tle-OH, Fmoc-Ala-OH (x2), Fmoc-αMeTrp(Boc)-OH, Fmoc-Gln(Trt)-OH (x2), and Fmoc-D-Phe-OH were coupled consecutively in a similar manner, except Fmoc-Gln(Trt)-OH was using HATU / HOAt / DIEPA(4 / 4 / 11 eq.) as coupling reagents. The synthesis continued with the addition of the linker, Fmoc-4-amino-(1-carboxymethyl) piperidine (4 eq.), at 45°C for 1.5 h x2 and then followed by the chelator DOTA(tBu)3(4 eq) at 25°C for 18 h. The coupling of the linker and the chelator were carried out by using HATU / HOAt / DIPEA (4 / 4 / 11 eq.). The peptide was then deprotected and simultaneously cleaved from the resin by treating with 92.5 / 2.5 / 2.5 / 2.5 TFA / TIS / DODT / H2O for 50 min at 40°C. After filtration, the crude peptide was precipitated by the addition of cold diethyl ether to the TFA solution and lyophilized in a H2O / MeCN mixture. The crude peptide was purified with prep HPLC using solvents A: H2O / 0.1% TFA and B: MeCN / 0.1% TFA, 20 mL / min (21%-31% B over 7 min, tR = 6.5 min). The sample was lyophilized to a white solid. Calc mass [M+2H]2+ / 2: 797.45 m / z; found [M+2H]2+ / 2: 797.50 m / z.

[0293] Other compounds were synthesized in similar manner. Table 1 lists the LC-MS data for the synthesized compounds.

[0294] Table 1: Mass values obtained from LC-MS spectrum of illustrative compounds

[0295] Synthesis of Lu-Compound 1

[0296] The precursor of compound 1 (7.4 mg, 4.6 µmol) was dissolved in 600 µL 0.2 NaOAc buffer (4.5 pH) and to it was added 5 eq of LuCl3(23 µmol). The solution was heated to 90°C for 30 minutes and the reaction mixture was then purified by HPLC using the semipreparative column. The HPLC conditions were 24% acetonitrile in water with 0.1% TFA at a flow rate of 4 mL / min (tR=8.3 min). The HPLC eluates containing the desired peptide were collected, pooled, and lyophilized. The yield was 65% with 95% purity. ESI-MS: calculated [M+2H]2+for Lu-Compound 1 C77H215N20O17[Lu] 883.4; found [M+2H]2+883.7.

[0297] Synthesis of La-Compound 1

[0298] The precursor of compound 1 (5.6 mg, 3.5 µmol) was dissolved in 500 µL 0.2 NaOAc buffer (4.5 pH) and to it was added 5 eq of LaCl3(23 µmol). The solution was heated to 90°C for 30 minutes and the reaction mixture was then purified by HPLC using the analytic column. The HPLC conditions were 23% acetonitrile in water with 0.1% TFA at a flow rate of 1 mL / min (tR=10.6 min). The HPLC eluates containing the desired peptide were collected, pooled, and lyophilized. The yield was 29% with 97% purity. ESI-MS: calculated [M+2H]2+for La-Compound 1 C77H215N20O17[La] 865.4; found [M+2H]2+865.7.

[0299] Radiolabelling of177Lu-Compound 1

[0300] 2.4 µL aliquot of compound 1 precursor (1 mM, 2.4 nmol) was dissolved in 205.3 µL 0.2 M NaOAc (pH 5.5), followed by 8.3 µL, 126.9 MBq of177LuCl3. Then, the reaction was heated to 95°C for 15 minutes. After cooling down, the reaction mixture was further diluted with the formulation buffer. For quality control, the formulated solutions were analyzed using radio-TLC (iTLC) and radio-HPLC. iTLCs were run on SG paper plates, with 0.1 M sodiumcitrate (5% MeOH) as the eluent. The developed plates were then read using a radio-TLC reading instrument. HPLC analyses were performed using an analytical Luna column, the mobile phase condition was using gradient from 5 to 85% acetonitrile in water with 0.1% TFA in 15 minutes at a flow rate of 1 mL / min (tR=10.8 min). The eluting components were visualized by UV (DAD) and radio-detection flow monitors. The radiochemical purity of177Lu-compound 1 at EOS (end of synthesis) and after 3h were > 99% by iTLC and HPLC with molar activity 44.57 MBq / nmol.

[0301] Radiolabelling of225Ac-Compound 1

[0302] 5 µL aliquot of compound 1 precursor (1 mM, 5 nmol) was dissolved in 138 µL 0.2 M NaOAc (pH 5.5) and 20 µL EtOH (10%), followed by 37.3 µL, 1.06 MBq of225AcCl3. Then, the reaction was heated to 95°C for 15 minutes. After cooling down, the reaction mixture was diluted with 3800 µL formulation buffer. For quality control, the formulated solutions were analyzed using radio-TLC (iTLC) and radio-HPLC. iTLCs were run on SG paper plates, with 0.1 M sodium citrate (5% MeOH) as the eluent. The developed plates were then read using a radio-TLC reading instrument. HPLC analyses were performed using an analytical Luna column with fraction collection. The mobile phase condition was using gradient from 5 to 85% acetonitrile in water with 0.1% TFA in 15 minutes at a flow rate of 1 mL / min (tR=10.8 min). The eluting components were visualized by UV (DAD) and radio-detection flow monitors. To detect the emissions resulting from the decay chain of225Ac, all collected fractions from HPLC were allowed to equilibrate for 6 h, then were placed in a Gamma counting instrument for subsequent measurements. The radiochemical purity of225Ac-compound 1 at EOS (end of synthesis) and after 3h was > 97% by iTLC and > 92 % by HPLC with molar activity of 0.17 MBq / nmol.

[0303] Example 2: In vitro competition binding assay

[0304] PC-3 cells were seeded at 2 × 105cells / well in 24-well poly-D-lysine plates 24-48 hours prior to the experiment. The growth medium was replaced by 400 μL of reaction medium (RPMI 1640 containing 2 mg / mL BSA, 4.8 mg / mL HEPES, 1 U / mL penicillin G and 1 μg / mL streptomycin). Cells were incubated for 30–60 min at 37 °C. Peptides as provided in Table 9 below provided in 50 μL of decreasing concentrations (10 μM to 1 pM) and 50 μL of 0.011 nM [125I-Tyr4]bombesin were added to wells. The cells were incubated with moderate agitation for 1 h at 27 °C, washed twice with ice-cold PBS, harvested by trypsinization, and measured for radioactivity on the gamma counter. Data were analyzed using nonlinear regression (one binding site model for competition assay) with GraphPad Prism 8.

[0305] Table 2: Binding affinities (Ki, nM) of GRPR-targeting peptides

[0306] Example 3: Ex vivo biodistribution in PC-3 tumor-bearing mice

[0307] Biodistribution studies were performed using male NOD.Cg-Rag1tm1MomIl2rgtm1Wjl / SzJ (NRG) mice and conducted according to the guidelines established by the Canadian Council on Animal Care and approved by Animal Ethics Committee of the University of British Columbia. For tumor inoculations, mice were anesthetized by inhalation with 2% isoflurane in oxygen and implanted subcutaneously with 5 × 106PC-3 cells below the leftshoulder. Imaging and biodistribution studies were performed only after tumors grew to 5-8 mm in diameter.

[0308] For ex vivo biodistribution studies, mice were injected with ∼20 kBq of the225Ac-labeled tracer. Mice were euthanized at various times (1h, 4h, 24h, 48h, 72h, 96h, and / or 120h p.i.), blood was drawn from heart, and organs / tissues of interest were collected, rinsed with PBS, blotted dry, weighed, and counted using an automated gamma counter. The uptake in each organ / tissue was normalized to the injected dose and expressed as the percentage of the injected dose per gram of tissue (%ID / g).

[0309] Biodistribution data is shown in Tables 3-11.

[0319] Example 4: Ex vivo biodistribution in PC-3 tumor-bearing mice

[0320] Biodistribution studies were performed using male NOD.Cg-Rag1tm1MomIl2rgtm1Wjl / SzJ (NRG) mice and conducted according to the guidelines established by the Canadian Council on Animal Care and approved by Animal Ethics Committee of the University of British Columbia. For tumor inoculations, mice were anesthetized by inhalation with 2% isoflurane in oxygen and implanted subcutaneously with 5 × 106PC-3 cells below the left shoulder. Imaging and biodistribution studies were performed only after tumors grew to 5-8 mm in diameter.

[0321] For ex vivo biodistribution studies, mice were injected with ∼1 MBq of the177Lu-labeled tracer. Mice were euthanized at various times (1h, 4h, 24h, 48h, 72h, and / or 120h, 144h p.i.), blood was drawn from heart, and organs / tissues of interest were collected, rinsed with PBS, blotted dry, weighed, and counted using an automated gamma counter. The uptake in each organ / tissue was normalized to the injected dose and expressed as the percentage of the injected dose per gram of tissue (%ID / g).

[0322] Biodistribution data is shown in Tables 12-14.

[0326] Example 5: Ex vivo biodistribution in PC-3 tumor-bearing mice

[0327] Biodistribution studies were performed using male NOD.Cg-Rag1tm1MomIl2rgtm1Wjl / SzJ (NRG) mice and conducted according to the guidelines established by the Canadian Council on Animal Care and approved by Animal Ethics Committee of the University of British Columbia. For tumor inoculations, mice were anesthetized by inhalation with 2% isoflurane in oxygen and implanted subcutaneously with 5 × 106PC-3 cells below the left shoulder. Imaging and biodistribution studies were performed only after tumors grew to 5-8 mm in diameter.

[0328] For ex vivo biodistribution studies, mice were injected with ~1 MBq of the177Lu or ~20 kBq of the225Ac-labeled tracer. Mice were euthanized at various times (1h, 4h, 24h, 48h, 72h, and / or 120h, 144h p.i.), blood was drawn from heart, and organs / tissues of interest were collected, rinsed with PBS, blotted dry, weighed, and counted using an automated gamma counter. The uptake in each organ / tissue was normalized to the injected dose and expressed as the percentage of the injected dose per gram of tissue (%ID / g).

[0329] The biodistribution data was decayed from injection to its corresponding time point. Mono-exponential and / or bi-exponential fits were performed to generate the time-activity-curves for each organ. Activity under the curve (AUC) values were then integrated for each organ.

[0330] Comparative Time-Activity Integration (AUC) of various radiotracers is shown in Table 15.

[0331] Table 15. Comparative Time-Activity Integration (AUC) of Radiotracers Uptake in Tumor, Pancreas, and Kidney.

[0332] All publications, patents and patent applications, including any drawings andappendices therein are incorporated by reference in their entirety for all purposes to the same extent as if each individual publication, patent or patent application, drawing, or appendix was specifically and individually indicated to be incorporated by reference in its entirety for all purposes. It will be apparent to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention as defined in the following claims. The scope of the invention should therefore not be limited by the preferred embodiments set forth in the above Examples, but should be given the broadest interpretation consistent with the description as a whole.

Claims

WHAT IS CLAIMED IS:

1. A compound of Formula (A), or a salt or solvate of Formula (A),Rradn6-RL-[linker]-RL-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-[ψ-Xaa9-(Xaa10)m2]m1-R (A) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; Xaa8is statine (Sta), Leu, D-Pro, Phe, cis-4-NHRa-D-Pro, or cis-4-ORa-D-Pro, wherein Rais alkyl, cycloalkyl, or aryl; R is -NH2or -NHOH; m1 is 0 or 1; m2 is 0 or 1; when m1 is 1 and m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m1 is 1 and m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, Me2Thz (5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid), or thiazoline-4-carboxylic acid (Thz); andXaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; each RLis independently absent, –(C1-6alkyl)-, –(C1-6alkyl)-C(O)–, –C(O)–, –NH–C(O)–, or –NH–C(S)–; the linker is a linear or branched chain of n1 units of -Xaa11-, and / or –L1R1– and / or –(L1)2R1–, wherein: n1 is 1-20; each Xaa11is independently an amino acid; each R1is, independently, a linear, branched, and / or cyclic C1-20alkylenyl, alkenylenyl and / or alkynylenyl, wherein any carbon bonded to two other carbons is optionally independently replaced by N, S, or O, and carbons are optionally independently substituted with oxo, hydroxyl, sulfhydryl, -SeH, halogen, guanidino, amine, amide, urea, carboxylic acid, sulfonic acid, sulfinic acid, or phosphoric acid; L1bonds to carbon, wherein each L1is independently –S–, –N(R2)C(O)–,–C(O)N(R2)–, –NH–C(O)–NH–, –NH–C(S)–NH–, , , ,or ; and R2is H, methyl or ethyl; optionally, the linker comprises an albumin binder (Ralb), wherein the albumin binder is: -(CH2)n3-CH3wherein n3 is 8-20; -(CH2)n4-C(O)OH wherein n4 is 8-20; wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, andR3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; or ; n6 is 1-5; andeach Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; wherein: (i) Xaa3is αMe-Trp, provided that the compound is not AMTG, AMTG2, and / or LW01186; (ii) Xaa7is Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); (iii) Xaa2is Gly, Arg, Asp, Glu, citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), or 2-amino-4-guanidinobutyric acid (Agb); (iv) m2 is 1; (v) at least one Rradis CROWN, CROWNGA, TCMC, PSC, a prosthetic group containing a trifluoroborate, an aryl or heteroaryl substituted with at least one radiohalogen, or an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; (vi) m1 is 0; or any combinations of (i)-(vi); and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated.

2. The compound of claim 1, wherein the peptidic compound has the structure of Formula (IA), or a salt or solvate of Formula (IA): Rradn6-[linker]-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-[ψ-Xaa9-(Xaa10)m2]m1-R (IA) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is αMe-Trp;Xaa4is Ala, D-Ala, or Ser; Xaa5is Val or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is statine (Sta), Leu, D-Pro, Phe, cis-4-NHRa-D-Pro or cis-4-ORa-D-Pro, wherein Rais alkyl, cycloalkyl, or aryl; R is -NH2or -NHOH; m1 is 0 or 1; when m1 is 1 and m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, or Leu, wherein Rais alkyl, cycloalkyl, or aryl; when m1 is 1 and m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; RLis absent, –(C1-6alkyl)-, –(C1-6alkyl)-C(O)–, –C(O)–, –NH–C(O)–, or –NH–C(S)–; the linker is a linear or branched chain of n1 units of -Xaa11-: n1 is 1-20; each Xaa11is independently an amino acid; optionally, the linker is bonded to an albumin binder (Ralb), wherein Ralbis: -(CH2)n3-CH3wherein n3 is 8-20; -(CH2)n4-C(O)OH wherein n4 is 8-20;wherein n2 is 1-5, n5 is 1-4, each R3ais independently H or methyl, and each R3bis independently I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; wherein n2 is 1-5, n5 is 1-4, each R3aisindependently H or methyl, and each R3bis independently I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; or ; n6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; wherein when Xaa5is Val, RLis absent, and the linker is 4-amino-(1-carboxymethyl)piperidine (Pip), then Rradis not DOTA or DOTAGA; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated.

3. The compound of claim 1 or 2, wherein RLis absent and the linker is p-aminomethylaniline-diglycolic acid (pABzA-DIG), a 4-amino-(1-carboxymethyl)piperidine (Pip), a 9-amino-4,7-dioxanonanoic acid (dPEG2), or a 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp).

4. The compound of any one of claims 1-3, wherein the peptidic compound has the structure of Formula (IA-1), or a salt or solvate of Formula (IA-1): Rrad-[linker]-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-ψ-Xaa9-(Xaa10)m2-R (SEQ ID NO: 2) (IA-1) wherein: Xaa1is an N-terminal amino acid residue of D-Phe; Xaa2is Gln; Xaa3is αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly; Xaa7is His; Xaa8is Sta or Leu; R is -NH2or -NHOH;when m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro or Leu; when m2 is 1, Xaa9is Pro or Leu; and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val or Tle; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; the linker is, wherein * indicates the connectivity to Rrad; Rradis a radiometal chelator; wherein when Xaa5is Val, then Rradis not DOTA or DOTAGA; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated.

5. The compound of claim 1, wherein the peptidic compound has the structure of Formula (IB-1), or a salt or solvate of Formula (IB-1): Rrad-[linker]-RL-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-ψ-Xaa9-(Xaa10)m2-R (IB-1) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala;Xaa7is Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is statine (Sta), Leu, D-Pro, or Phe; R is -NH2or -NHOH; m2 is 0 or 1; when m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, Me2Thz (5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; the linker and RLtogether form a p-aminomethylaniline-diglycolic acid (pABzA-DIG) linker, a 4-amino-(1-carboxymethyl)piperidine (Pip) linker, a 9-amino-4,7-dioxanonanoic acid (dPEG2) linker, or a 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp) linker; Rradis a radiometal chelator; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated.

6. The compound of any one of claims 1, 2, and 5, wherein Xaa7is Trp, Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala).

7. The compound of claim 5, wherein Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly; Xaa7is Trp, Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), 2-quinoylalanine (2-Quin-Ala), or3-quinoylalanine (3-Quin-Ala); and Xaa8is Sta or Leu.

8. The compound of claim 1, wherein the peptidic compound has the structure of Formula (IC-1), or a salt or solvate of Formula (IC-1): Rrad-[linker]-RL-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-ψ-Xaa9-(Xaa10)m2-R (IC-1) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Glu, citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), or 2-amino-4-guanidinobutyric acid (Agb); Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is statine (Sta), Leu, D-Pro, or Phe; R is -NH2or -NHOH; m2 is 0 or 1; when m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro),4,4-difluoroproline (difluoroPro), Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; the linker and RLtogether form a p-aminomethylaniline-diglycolic acid (pABzA-DIG) linker, a 4-amino-(1-carboxymethyl)piperidine (Pip) linker, a 9-amino-4,7-dioxanonanoic acid (dPEG2) linker, or a 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp) linker; Rradis a radiometal chelator; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated.

9. The compound of claim 8, wherein Xaa1is an N-terminal amino acid residue D-Phe; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly; Xaa7is His, Trp, Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); and Xaa8is Sta or Leu.

10. The compound of any one of claims 1-9, wherein m2 is 0.

11. The compound of claim 10, wherein Xaa9-R is a C-terminally amidated (R is -NH2) amino acid residue selected from Pro or Leu.

12. The compound of claim 1, wherein the peptidic compound has the structure of Formula (ID-1), or a salt or solvate of Formula (ID-1): Rrad-[linker]-RL-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-ψ-Xaa9-(Xaa10)m2-R (ID-1) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His;Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is statine (Sta), Leu, D-Pro, or Phe; Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz); R is -NH2or -NHOH; m2 is 1; Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; the linker and RLtogether form a p-aminomethylaniline-diglycolic acid (pABzA-DIG) linker, a 4-amino-(1-carboxymethyl)piperidine (Pip) linker, a 9-amino-4,7-dioxanonanoic acid (dPEG2) linker, or a 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp) linker; Rradis a radiometal chelator; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated.

13. The compound of claim 12, wherein Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle;Xaa6is Gly; Xaa7is His, Trp, Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is Sta or Leu; and Xaa9is Pro or Leu.

14. The compound of claim 12 or 13, wherein Xaa10-R is a C-terminally amidated (R is -NH2) amino acid residue selected from Val or Tle.

15. The compound of claim 1, wherein the peptidic compound has the structure of Formula (IE-1), or a salt or solvate of Formula (IE-1): Rrad-RL-[linker]-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-ψ-Xaa9-(Xaa10)m2-R (IE-1) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is statine (Sta), Leu, D-Pro, or Phe R is -NH2or -NHOH; m2 is 0 or 1;when m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; RLis independently absent, –(C1-3alkyl)-, –(C1-3alkyl)-C(O)–, –C(O)–, –NH–C(O)–, or –NH–C(S)–; the linker is a linear or branched chain of n1 units of -Xaa11-, and / or –L1R1– and / or –(L1)2R1–, wherein: n1 is 1-6; each Xaa11is independently an amino acid; each R1is, independently, a linear, branched, and / or cyclic C1-6alkylenyl, C2-6alkenylenyl and / or C2-6alkynylenyl, wherein any carbon bonded to two other carbons is optionally independently replaced by N, S, or O, and carbons are optionally independently substituted with oxo, hydroxyl, sulfhydryl, -SeH, halogen, guanidino, amine, amide, urea, carboxylic acid, sulfonic acid, sulfinic acid, or phosphoric acid; L1bonds to carbon, wherein each L1is independently –S–, –N(R2)C(O)–,–C(O)N(R2)–, –NH–C(O)–NH–, –NH–C(S)–NH–, , , ,or ; andRradis CROWN, CROWNGA, TCMC, PSC, a prosthetic group containing a trifluoroborate, an aryl or heteroaryl substituted with at least one radiohalogen, or an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated.

16. The compound of claim 15, wherein the linker is -Xaa11-.

17. The compound of claim 15 or 16, wherein: RLis absent or –C(O)–; and the linker is p-aminomethylaniline-diglycolic acid (pABzA-DIG), a 4-amino-(1-carboxymethyl)piperidine (Pip), a 9-amino-4,7-dioxanonanoic acid (dPEG2), or a 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp).

18. The compound of claim 15, wherein the linker is *-Xaa11–R1L1–, where * indicates the connectivity to Xaa1.

19. The compound of claim 18, wherein the linker is *-Xaa11–C(O)CH2–L1–, where *indicates the connectivity to Xaa1 and L1 is , or .

20. The compound of claim 18 or 19, wherein RLis –CH2– or absent.

21. The compound of any one of claims 15-20, wherein Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly; Xaa7is His, Trp, Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is Sta or Leu; and Xaa9is Pro or Leu.

22. The compound of claim 1, wherein the peptidic compound has the structure of Formula (IF-1), or a salt or solvate of Formula (IF-1): Rrad-RL-[linker]-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8--R (IF-1) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit),2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(5-OH), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; R is -NH2or -NHOH; Xaa8-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from is statine (Sta), Leu, D-Pro, Phe, cis-4-NHRa-D-Pro or cis-4-ORa-D-Pro, wherein Rais alkyl, cycloalkyl, or aryl; the linker and RLtogether form a p-aminomethylaniline-diglycolic acid (pABzA-DIG) linker, a 4-amino-(1-carboxymethyl)piperidine (Pip) linker, a 9-amino-4,7-dioxanonanoic acid (dPEG2) linker, or a 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp) linker; Rradis a radiometal chelator; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, or Xaa8, is each optionally N-methylated.

23. The compound of claim 22, wherein Xaa8-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from cis-4-NHRa-D-Pro or cis-4-ORa-D-Pro, wherein Rais C1-C6alkyl, C3-C7cycloalkyl, or phenyl.

24. The compound of claim 22 or 23, wherein Xaa8-R is a C-terminally amidated (R is -NH2) amino acid residue selected from cis-4-cyclohexyloxy-D-Pro or cis-4-cyclohexylamino-D-Pro.

25. The compound of any one of claims 22-24, wherein Xaa1is an N-terminal amino acid residue D-Phe; Xaa2is Gln or Cit;Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly; and Xaa7is His, Trp, Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala).

26. The compound of any one of claims 1-17 and 21-25, wherein the linker and RLtogether form a Pip linker.

27. The compound of any one of claims 1-26, wherein Xaa1is an N-terminal amino acid residue of D-Phe.

28. The peptidic compounds of claim 1, wherein the peptidic compounds do not include an albumin binder Ralb.

29. The compound of claim 1, wherein the compound has the structure of Formula (IIA), or a salt or solvate of Formula (IIA), Rrad-[linker]-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-ψ-Xaa9-(Xaa10)m2-R (IIA) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa4is Ala, D-Ala, or Ser, ; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me),Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is statine (Sta), Leu, D-Pro, or Phe; R is -NH2or -NHOH; m2 is 0 or 1; when m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, Me2Thz (5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, Me2Thz (5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; the linker is: a linear peptide of 3 to 6 amino acid residues, –Xaa11A–Xaa11B–(Xaa11C)1˗4–, wherein Xaa11A, Xaa11B, and Xaa11Care each independently an amino acid and wherein the radiolabeling group and the albumin-binding group are bonded to the free N-terminus of Xaa11Aand the side chain of Xaa11B, respectively, or are bonded to the side chain of Xaa11Band the free N-terminus of Xaa11A, respectively; or a branched peptide of 3 to 6 amino acid residues, –Xaa11B(Xaa11A)–(Xaa11C)1-4–, wherein Xaa11A, Xaa11B, and Xaa11Care each independently an amino acid and wherein the C-terminus of Xaa11Aforms an amide with the side chain of Xaa11B, and wherein the radiolabeling group and the albumin-binding group are bonded to the free N-termini of Xaa11Aand Xaa11B, respectively, or are bonded to the free N-termini of Xaa11Band Xaa11A, respectively; Ralbisn2 is 1-5; n5 is 1-4; each R3ais independently H or methyl; each R3bis independently I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl;Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, or Xaa10is each optionally methylated.

30. The compound of claim 29, wherein Ralbis .

31. The compound of claim 29 or 30, wherein: Xaa1is an N-terminal amino acid residue of D-Phe; Xaa2is Gln or Cit; Xaa3is Trp or αMe-Trp; Xaa4is Ala; Xaa5is Val or Tle; Xaa6is Gly; Xaa7is His, Trp, Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); and Xaa8is Sta or Leu.

32. A compound of Formula (B-1), or a salt or solvate of Formula (B-1), Rrad-[linker]-Xaa13-[Xaa12-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-ψ-Xaa9-(Xaa10)m2-R]2(B-1) wherein: Xaa12is an N-terminal amino acid residue selected from p-aminomethylaniline-diglycolic acid (pABzA-DIG), 4-amino-(1-carboxymethyl)piperidine (Pip), 9-amino-4,7-dioxanonanoic acid (dPEG2), or 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp); Xaa1is D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me),Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); Xaa8is statine (Sta), Leu, D-Pro, or Phe; R is -NH2or -NHOH; m2 is 0 or 1; when m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz); and Xaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; Xaa13is an amino acid with a sidechain comprising a carboxylic acid, wherein one Xaa12is bonded to the C-terminus of Xaa13and the other Xaa12is bonded to the sidechain of Xaa13; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; the linker absent or is a linear or branched chain of n1 units of -Xaa11-, wherein: n1 is 1-6; each Xaa11is independently an amino acid; Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leavinggroup; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated.

33. The compound of claim 32, wherein Xaa1is D-Phe.

34. The compound of claim 32 or 33, wherein Xaa13is Glu, D-Glu, Asp, or D-Asp.

35. The compound of any one of claims 1-34, wherein R is -NH2.

36. The compound of any one of claims 1-35, wherein ψ represents a reduced peptide bond.

37. The compound of any one of claims 1-7 and 10-36, wherein Xaa2is Gln or Cit.

38. The compound of any one of claims 1-37, wherein Xaa3is αMe-Trp.

39. The compound of any one of claims 1-38, wherein Xaa4is Ala.

40. The compound of any one of claims 1-39, wherein Xaa5is Val or Tle.

41. The compound of any one of claims 1-40, wherein Xaa6is Gly.

42. The compound of any one of claims 1-4 and 8-41, wherein Xaa7is His, Trp, Trp(5-F), or 3-quinoylalanine (3-Quin-Ala).

43. The compounds of any one of claims 1-42, wherein at least one of Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is N-methylated.

44. The compound of any one of claims 1-42, wherein Xaa6is N-methylated.

45. The compound of any one of claims 2-14, wherein Rradn6-[linker]-RL- is DOTA-Pip-, DOTA-Pip-, CROWN-Pip-, or CROWNGA-Pip-.

46. The compound of any one of claims 1-4 and 15-21, wherein at least one Rradis a radiometal chelator.

47. A compound of Formula (I), or a salt or solvate of Formula (I), Rradn6-[linker]-Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-[ψ-Xaa9-(Xaa10)m2]m1-R (I) wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, 4-chlorophenylalanine (Cpa), D-Cpa, 3-(1-naphthyl)alanine (Nal), D-Nal, 3-(2-naphthyl)alanine (2-Nal), D-2-Nal, 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-3-carboxylic acid (Tpi), or D-Tpi; Xaa2is Gly, Arg, Asp, Asn, Gln, Glu, homoserine (Hse), citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), 2-amino-4-guanidinobutyric acid (Agb), or His; Xaa3is Trp, β-(3-benzothienyl)alanine (Bta), Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, Tpi, 7-azatryptophan (7-Aza), NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; Xaa4is Ala, D-Ala, or Ser; Xaa5is Val, 2,3-dehydro-Val, cyclopentylglycine (Cpg), L-cyclopropylglycine, L-cyclobutylglycine, or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is His, Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine, or 3-quinoylalanine; Xaa8is statine (Sta), Leu, D-Pro, Phe, cis-4-NHRa-D-Pro or cis-4-ORa-D-Pro, wherein Rais alkyl, cycloalkyl, or aryl; R is -NH2or -NHOH; m1 is 0 or 1; m2 is 0 or 1; when m1 is 1 and m2 is 0, Xaa9-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), cis-4-NHRa-D-Pro, cis-4-ORa-D-Pro, Leu, 5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid (Me2Thz), or thiazoline-4-carboxylic acid (Thz), wherein Rais alkyl, cycloalkyl, or aryl; when m1 is 1 and m2 is 1, Xaa9is Pro, Phe, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), 4,4-difluoroproline (difluoroPro), Leu, Me2Thz (5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid), or thiazoline-4-carboxylic acid (Thz); andXaa10-R is a C-terminally amidated (R is -NH2) or a C-terminally hydroxylamidated (R is -NHOH) amino acid residue selected from Val, Leu, Tle, Ile, Nle, Ala, Gly, or Met; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; the linker is a linear or branched chain of n1 units of -Xaa11-; n1 is 1-20; each Xaa11is independently an amino acid; optionally, the linker comprises an albumin binder (Ralb), wherein the albumin binder is: -(CH2)n3-CH3wherein n3 is 8-20; -(CH2)n4-C(O)OH wherein n4 is 8-20; wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl;wherein n2 is 1-5, n5 is 1-4, R3ais H or methyl, and R3bis I, Br, F, Cl, H, OH, OCH3, NH2, NO2or C1-C6alkyl; orn6 is 1-5; each Rradis a radiolabeling group independently selected from a radiometal chelator; an aryl or heteroaryl substituted with at least one radiohalogen; a prosthetic group containing a trifluoroborate; an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; a prosthetic group containing a silicon-fluorine-acceptor moiety; or a prosthetic group containing a fluorophosphate, fluorosulfate, sulfonyl fluoride, or a combination thereof; wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9or Xaa10is each optionally N-methylated; and wherein: (i) Xaa3is αMe-Trp, provided that the compound is not AMTG, AMTG2, and / or LW01186; (ii) Xaa7is Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I),Trp(5-OH), αMe-Trp, NaI, 2-pyridylalanine (2-Pal), 3-pyridylalanine (3-Pal), 4-pyridylalanine (4-Pal), 2-quinoylalanine (2-Quin-Ala), or 3-quinoylalanine (3-Quin-Ala); (iii) Xaa2is Gly, Arg, Asp, Glu, citrulline (Cit), 2-amino-4-ureidobutanoic acid (Aub), or 2-amino-4-guanidinobutyric acid (Agb); (iv) m2 is 1; (v) at least one Rradis CROWN, CROWNGA, TCMC, PSC, a prosthetic group containing a trifluoroborate, an aryl or heteroaryl substituted with at least one radiohalogen, or an aryl or heteroaryl substituted with at least one fluorine precursor leaving group; (vi) m1 is 0; or (vii) any combinations of (i)-(vi).

48. The compound of claim 47, wherein: Xaa1is an N-terminal amino acid residue selected from D-Phe, D-Cpa, D-Nal, or D-2-Nal; Xaa2is Asp, Asn, Gln, or Glu; Xaa3is Trp, Trp(Me), αMe-Trp, Trp(7-F), Trp(6-F), Trp(5-F), or Trp(4-F); Xaa4is Ala or D-Ala; Xaa5is Val or tert-leucine (Tle); Xaa6is Gly or D-Ala; Xaa7is Trp, Trp(Me), Trp(7-Me), Trp(6-Me), Trp(5-Me), Trp(4-Me), Trp(2-Me), Trp(7-F), Trp(6-F), Trp(5-F), Trp(4-F), Trp(7-Cl), Trp(6-Cl), Trp(5-Cl), Trp(4-Cl), Trp(7-Br), Trp(6-Br), Trp(5-Br), Trp(4-Br), Trp(7-I), Trp(6-I), Trp(5-I), Trp(4-I), Trp(5-OH), or αMe-Trp; Xaa8is Leu; m1 is 1 and m2 is 0; Xaa9is Pro, oxazolidine-4-carboxylic acid (4-oxa-L-Pro), or 4,4-difluoroproline (difluoroPro); R is -NH2; ψ represents a peptide bond or reduced peptide bond joining Xaa8to Xaa9; the linker comprises p-aminomethylaniline-diglycolic acid (pABzA-DIG),4-amino-(1-carboxymethyl)piperidine (Pip, 9-amino-4,7-dioxanonanoic acid (dPEG2), or 4-(2-aminoethyl)-1-carboxymethyl-piperazine (Acp), wherein the linker optionally comprises an albumin binder; n6 is 1; Rradis a radiometal chelator; and wherein Xaa1, Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, or Xaa9is each optionallyN-methylated.

49. The compound of any one of claims 1-48, wherein the radiometal chelator is selected from the group consisting of DOTA and derivatives; DOTAGA; NOTA; NODAGA; NODASA; CB-DO2A; 3p-C-DEPA; TCMC; DO3A; DTPA and DTPA analogues optionally selected from CHX-A”-DTPA and 1B4M-DTPA; TETA; NOPO; Me-3,2-HOPO; CB-TE1A1P; CB-TE2P; MM-TE2A; DM-TE2A; sarcophagine and sarcophagine derivatives optionally selected from SarAr, SarAr-NCS, diamSar, AmBaSar, and BaBaSar; TRAP; AAZTA; DATA and DATA derivatives; H2-macropa or a derivative thereof; H2dedpa, H4octapa, H4py4pa, H4Pypa, H2azapa, H5decapa, and other picolinic acid derivatives; CP256; PCTA; C-NETA; C-NE3TA; HBED; SHBED; BCPA; CP256; YM103; desferrioxamine (DFO) and DFO derivatives; H6phospa; a trithiol chelate; mercaptoacetyl; hydrazinonicotinamide; dimercaptosuccinic acid; 1,2-ethylenediylbis-L-cysteine diethyl ester; methylenediphosphonate; hexamethylpropyleneamineoxime; hexakis(methoxy isobutyl isonitrile), H4py4pa-phenyl-NCS, PSC, CROWN, and CROWNGA.

50. The compound of any one of claims 1-49, wherein the radiometal chelator is DOTA, DOTAGA, CROWN, or CROWNGA.

51. The compound of any one of claims 1-50, wherein the radiometal chelator is bound by or conjugated with a radiometal or a radiohalogen containing metal.

52. The compound of any one of claims 1-51, wherein the radiometal chelator is bound by or conjugated with a radiometal or a radiohalogen containing metal selected from [18F]AlF,44Sc,47Sc,61Cu,64Cu,67Cu,67Ga,68Ga,72As,77As,86Y,89Zr,90Y,90Nb,94mTc,99mTc,105Rh,109Pd,111In,114mIn,117mSn,132La,133La,134La,135La,134Ce,142Pr,149Pm,149Tb,152Tb,155Tb,159Gd,161Tb,165Er,166Ho,175Yb,177Lu,186Re,188Re,198Au,199Au,203Pb,211At,212Pb,212Bi,213Bi,225Ac, or227Th.

53. The compound of any one of claims 1-52, wherein the radiometal chelator is bound by a radiometal selected from68Ga,177Lu, or225Ac.

54. The compound of any one of claims 1-4 and 15-21, wherein at least one Rradis a trifluoroborate containing prosthetic group BF3–R5–R4–, R4is –(CH2)1-5–;BF3–R5– forms ; R5aand R5bare each independently a C1-C5linear or branched alkyl.

55. The compound of claim 54, wherein R4is –CH2– and R5aand R5bare each methyl.

56. The compound of any one of claims 1-4 and 15-21, wherein at least one Rradis an aryl or heteroaryl substituted with at least one fluorine precursor leaving group.

57. The compound of claim 56, wherein the at least one precursor leaving group is -NMe3+, -NO2, F, Cl, Br, I, -CN, or -CF3. I 58. The compound of claim 56 or 57, wherein at least one Rradis an aryl or a pyridyl substituted with at least one -NMe3+, -NO2, F, Cl, Br, I, -CN, or -CF3.

59. The compound of any one of claims 56-58, at least one Rradis .

60. The compound of any one of claims 1-4 and 15-21, wherein at least one Rradis an aryl or a heteroaryl substituted with at least one radiohalogen.

61. The compound of claim 60, wherein at least one Rradis an aryl or a pyridyl substituted with at least one18F.

62. The compound of claim 60 or 61, at least one Rradis .

63. The compound of claim 1 or 2 selected from(SEQ ID NO: 22), (SEQ ID NO: 23), (SEQ ID NO: 24), (SEQ ID NO: 25), or ( SEQ ID NO: 52), or a salt or a solvate thereof.

64. The compound of claim 1 or 5 selected from (SEQ ID NO: 26), (SEQ ID NO: 47), (SEQ ID NO: 30), (SEQ ID NO: 28), (SEQ ID NO: 32),(SEQ ID NO: 49), (SEQ ID NO: 34), (SEQ ID NO: 35), (SEQ ID NO: 58), (SEQ ID NO: 51),(SEQ ID NO: 41), (SEQ ID NO: 42), or (SEQ ID NO: 44), or a salt or a solvate thereof.

65. The compound of claim 1 or 8 selected from (SEQ ID NO: 36),(SEQ ID NO: 37), (SEQ ID NO: 38), or (SEQ ID NO: 43), or a salt or a solvate thereof.

66. The compound of claim 1 or 12 selected from (SEQ ID NO: 47), (SEQ ID NO: 48),(SEQ ID NO: 49), (SEQ ID NO: 50), (SEQ ID NO: 51), (SEQ ID NO: 41), or (SEQ ID NO: 53), or a salt or a solvate thereof.

67. The compound of claim 1 or 47 selected from (SEQ ID NO: 59), (SEQ ID NO: 46), (SEQ ID NO: 26),(SEQ ID NO: 27), (SEQ ID NO: 30),(SEQ ID NO: 31), (SEQ ID NO: 28), (SEQ ID NO: 29),(SEQ ID NO: 32), or (SEQ ID NO: 33), or a salt or a solvate thereof.

68. The compound of claim 1 or 22 selected from(SEQ ID NO: 39) or(SEQ ID NO: 40), or a salt or a solvate thereof.

69. The compound of claim 1 or 29 selected from (SEQ ID NO: 64) or(SEQ ID NO: 65), or a salt or a solvate thereof.

70. The compound of claim 1 or 32 selected from (SEQ ID NOs: 54 and 55) or (SEQ ID NOs: 56 and 57), or a salt or a solvate thereof.

71. The compound of any one of claims 51 and 63-70, wherein the compound is conjugated with [18F]AlF,44Sc,47Sc,61Cu,64Cu,67Cu,67Ga,68Ga,72As,77As,86Y,89Zr,90Y,90Nb,94mTc,99mTc,105Rh,109Pd,111In,114mIn,117mSn,132La,133La,134La,135La,134Ce,142Pr,149Pm,149Tb,152Tb,155Tb,159Gd,161Tb,165Er,166Ho,175Yb,177Lu,186Re,188Re,198Au,199Au,203Pb,211At,212Pb,212Bi,213Bi,225Ac, or227Th.

72. The compound of any one of claims 51 and 63-70, wherein the compound is conjugated with [18F]AlF,44Sc,61Cu,64Cu,67Ga,68Ga,72As,86Y,89Zr,90Nb,99mTc,110mIn,111In,123I,124I,131I,132La,133La,134La,134Ce,152Tb,155Tb, or203Pb.

73. The compound of any one of claims 51 and 63-70, wherein the compound is conjugated with47Sc,64Cu,67Cu,77As,90Y,105Rh,109Pd,111In,117mSn,135La,142Pr,149Tb,149Pm,153Sm,159Gd,161Tb,165Er,166Ho,175Yb,177Lu,186Re,188Re,198Au,199Au,211At,212Pb,212Bi,213Bi,223Ra,224Ra,225Ac, or227Th.

74. The compound of any one of claims 51 and 63-70, wherein compound is conjugated with68Ga,177Lu, or225Ac.

75. The compound of claim 51 or 67, wherein compound is conjugated with203Pb or212Pb.

76. The compound of claim 1 or 15, wherein the compound is (SEQ ID NO: 62), or a salt or a solvate thereof.

77. The compound of claim 1 or 15, wherein the compound is (SEQ ID NO: 60), or a salt or a solvate thereof.

78. The compound of claim 77, wherein at least one fluorine in -BF3¯ is18F.

79. The compound of claim 77 or 78, wherein all fluorines in -BF3¯ is18F.

80. The compound of claim 1 or 15, wherein the compound is (SEQ ID NO: 63), or a salt or a solvate thereof.

81. A composition comprising a compound of any one of claims 1-80 and a pharmaceutically acceptable carrier or excipient.

82. A method of imaging gastrin-releasing peptide receptor (GRPR)-expressing tissue in a subject, the method comprising: administering to the subject a compound of any one of claims 1-80 or a composition of claim 81; and imaging tissue of the subject.

83. A method of treating cancer in a subject comprising, administering to the subject in need thereof a therapeutically effective amount of a compound of any one of claims 1-80 or a composition of claim 81.

84. The method of claim 83, wherein the cancer is prostate cancer, lung cancer, head and neck cancer, colon cancer, kidney cancer, ovarian cancer, liver cancer, pancreatic cancer, breast cancer, glioma or neuroblastoma.

85. The method of claim 84, wherein the cancer is breast cancer or glioblastoma.

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