Radiopharmaceutical imaging method of adenomyosis

Abstract

The present invention relates to methods of imaging adenomyosis using the radiopharmaceutical agent 99mTc-maraciclatide. The technetium-99m radiopharmaceutical is suitably prepared from a non-radioactive kit containing the RGD peptide maraciclatide. Also described are methods of diagnosis, therapy selection and therapy monitoring of adenomyosis using the agent. The invention also includes the use of the kit and / or gamma camera or gamma detector in the methods of the invention.

Description

[0001] 2025.05.09 Specification – P000705WO 1 Radiopharmaceutical Imaging Method. Field of the Invention. The present invention relates to methods of imaging adenomyosis using the radiopharmaceutical agent99mTc-maraciclatide. The technetium-99m radiopharmaceutical is suitably prepared from a non-radioactive kit. Also described are methods of diagnosis, therapy selection and therapy monitoring of adenomyosis using the agent. The invention also includes the use of the kit and / or gamma camera or gamma detector in the methods of the invention. Background to the Invention. Adenomyosis is a benign disorder of the uterus, in which endometrial tissue, that is tissue from the lining of the uterus (i.e. the endometrium) grows into the muscle wall (or myometrium) of the mammalian uterus. The endometrium is the epithelial lining of the cavity of the uterus along with its mucous membrane. In humans, the endometrial lining is normally shed once a month during menstruation, and then regrows. Adenomyosis can lead to symptoms of heavy, painful and prolonged menstrual periods, as well as chronic pelvic pain, pain during sex and potential infertility. Up to one third of adenomyosis patients can, however, be asymptomatic. In contrast, endometriosis is a gynaecological disorder of the female reproductive system, characterised by the presence of abnormal (i.e. ectopic, out of place), proliferating endometrial cells outside the uterus. Adenomyosis is a “poorly understood condition” [Schrager et al, Am.Fam.Physician, 105(1), 33-38 (2022)], with the diagnosis and classification of the disease still an evolving situation. Khan et al [J.Clin Med., 11, 4057 (2022) states that “The exact pathogenesis of adenomyosis is still elusive”. Vannuccini et al [F1000Research 2019, 8(F1000 Faculty Rev), 283 (2019)] report that: (a) there are currently no international guidelines for the surgical or medical treatment of adenomyosis; (b) although adenomyosis has historically been considered a condition of multiparous women >40 years old who have pain and heavy menstrual bleeding, diagnosed at hysterectomy, the epidemiological scenario has changed completely; (c) adenomyosis is increasingly 2025.05.09 Specification – P000705WO 2 identified in young women with pain, and or infertility in which endometriosis may also be present. CN 110964086 B discloses an integrin polypeptide having the sequence RWRNR [arginine-Tryptophan-(D-Arginine)-Asparagine-Arginine], and labelled versions thereof for in vivo imaging via fluorescence, ultrasound, CT, PET or MRI. The agents are claimed to be useful in the diagnosis of diseases such as acute and chronic hepatic nephropathy, rheumatoid arthritis, adenomyosis, thrombosis, and cancers in which the integrin beta 3 receptor is highly expressed; including breast cancer, cervical cancer, liver cancer, brain glioma, prostate cancer, ovarian cancer, gastric cancer and melanoma. The supporting data of CN 110964086 B is limited to uptake of a dye- labelled peptide in a murine tumour model. WO 03 / 006491 discloses compounds of Formula (I): (I) or pharmaceutically acceptable salt thereof wherein: G represents glycine D represents aspartic acid R1represents -(CH2)n- or -(CH2)n-C6H4- wherein n represents a positive integer 1 to 10, h represents a positive integer 1 or 2, X1represents an amino acid residue wherein said amino acid possesses a functional side-chain such as an acid or amine, X2and X4represent independently an amino acid residue capable of forming a disulfide bond, X3represents arginine, N-methylarginine or an arginine mimetic, X5represents a hydrophobic amino acid or derivatives thereof, 2025.05.09 Specification – P000705WO 3 X6represents a thiol-containing amino acid residue, X7 is absent or represents a biomodifier moiety, Z1represents an anti-neoplastic agent, a chelating agent or a reporter moiety and W1is absent or represents a spacer moiety. WO 03 / 006491 discloses that a preferred chelating moiety has the formula shown, and includes99mTc complexes of said chelator conjugate of Formula I therein: WO 03 / 006491 states that: “Diseases and indications associated with angiogenesis are e.g. different forms of cancer and metastasis, e.g. breast, skin, colorectal, pancreatic, prostate, lung or ovarian cancer. Other diseases and indications are inflammation (e.g. chronic), atherosclerosis, rheumatoid arthritis and gingivitis. Further diseases and indications associated with angiogenesis are arteriovenous malformations, astrocytomas, choriocarcinomas, glioblastomas, gliomas, haemangiomas (childhood, capillary), hepatomas, hyperplastic endometrium, ischemic myocardium, endometriosis, Kaposi sarcoma, macular degeneration, melanoma, neuroblastomas, occluding peripheral artery disease, osteoarthritis, psoriasis, retinopathy (diabetic, proliferative), scleroderma, seminomas and ulcerative colitis.” However, this is a broad list of possibilities and WO 03 / 006491 does not disclose which agents and ‘reporter moieties’ within the scope would be useful for which medical conditions, and how each of these conditions may be imaged in a way that can be usefully interpreted. Edwards et al [Nucl.Med.Biol., 35, 365-375 (2008)] discloses that99mTc-NC100692 (99mTc-maraciclatide) is being developed as an in vivo diagnostic marker of vitronectin integrin receptor expression. Edwards suggests that a marker of 2025.05.09 Specification – P000705WO 4 vitronectin expression could be of value in the diagnosis or monitoring of angiogenesis associated with: cancer, atherosclerosis, rheumatoid arthritis, chronic inflammation and endometriosis. The Edwards publication relates to an agent “in development” and is limited to in vitro vitronectin affinity data, plus biodistribution in rats – no evidence of utility in humans or radiopharmaceutical imaging feasibility for any of the disease states described is provided. Harmsen et al [Human Reprod. Update, 25(5), 647-671 (2019)] review the literature on the possible role of abnormal vascularisation and angiogenesis in adenomyosis. Harmsen teaches (page 662) that “the potential role of angiogenesis in the pathophysiology of adenomyosis and its related symptoms is complex”. Harmsen discusses a range of angiogenic parameters (Table 1, pages 652-654), but neither vitronectin nor αvβ3 / 5 integrins are included. Harmsen states (page 663) “VEGF is a specific and important angiogenic parameter….” Harmsen (page 665) concludes with a discussion on the possible implications for the treatment of adenomyosis - if ongoing angiogenesis in the occurrence of adenomyosis can indeed be confirmed. Harmsen is silent on the diagnosis or imaging of adenomyosis. Rossi et al [Curr.Obstet.Gyneco.Rep., 11, 95-102 (2022)] reviews all the mechanisms involved in the pathogenesis of adenomyosis. A wide variety of factors associated with inflammation, neurogenesis, fibrosis and neoangiogenesis are discussed (Figure 1 page 97). Rossi concludes (page 100) that “Further studies are needed to have a better comprehension of all the mechanisms involved in this disease, leading to a more precise diagnosis and treatment”. Moawad et al [J.Clin.Med., 12, 4828 (2023)] review the diagnosis and classification of adenomyosis. They report and discuss many studies based on MRI or ultrasonography, but none using other imaging modalities. EP 2598175 B1 (WO 2012 / 013701 A1) discloses radiopharmaceutical compositions of the bicyclic RGD peptide maraciclatide, labelled with99mTc and stabilised with para-aminobenzoic acid (pABA). Also described are non-radioactive kits containing pABA for the preparation of such radiopharmaceutical compositions. 2025.05.09 Specification – P000705WO 5 US 10,729,793 (WO 2016 / 207636 A1) discloses methods of imaging arthritis using radiopharmaceuticals based on chelator conjugates of bicyclic RGD peptides similar to those of Formula I of WO 03 / 006491 (above). A preferred such radiopharmaceutical for imaging arthritis is99mTc-maraciclatide. WO 2023 / 166305 A1 discloses a method of imaging site(s) of endometriosis in a subject, which comprises prior administration of the radiopharmaceutical99mTc- maraciclatide to said subject, followed by extra-uterine imaging of the radioactive emissions from said99mTc-maraciclatide in vivo, wherein said site(s) comprise one or more of the following: (i) abdominal endometriosis; (ii) peritoneal endometriosis; (iii) thoracic endometriosis. Endometriosis is a distinct condition from adenomyosis, characterised by the presence of abnormal (i.e. ectopic, out of place), proliferating endometrial cells outside the uterus. However, the symptoms from endometriosis and adenomyosis may overlap. Although the99mTc-maraciclatide radiopharmaceutical of the present invention has been previously used to image and diagnose endometriosis, its use to image and diagnose adenomyosis is surprising. Whereas endometriosis is characterised by abnormal blood vessel formation, adenomyosis is thought to also be mediated through lesion growth and a local inflammatory response, although the pathogenesis remains unclear. These are therefore distinct conditions with different underlying etiology. Furthermore, whereas endometriosis is associated with genomic integrin expression, targeted by the radiopharmaceutical, adenomyosis is not. Summary of the Present Invention. Differential diagnosis of adenomyosis to distinguish it from other potentially comorbid disease with similar signs and symptoms such as endometriosis is a significant challenge. A recent review concluded that no biomarkers tested could diagnose or rule out adenomyosis with high certainty [Burghaus et al, Int. J. Gynecol Obstet., 164: 305-314. (2024) doi:10.1002 / ijgo.15062]. The current diagnosis of 2025.05.09 Specification – P000705WO 6 adenomyosis involves: a physical examination; imaging via TVUS (trans-vaginal ultrasound) or MRI; or perhaps biopsy. Definitive diagnosis of adenomyosis requires a histologic examination of uterine tissue. TVUS is generally the first imaging test used because it is usually well-tolerated, available and affordable. However, even when performed by an expert sonographer, it is not 100% accurate and lesions can be missed. This may be because the lesion is small or because of low image quality (e.g. due to scar tissue after a previous operation or because of shadow caused by bowel content). This also means that the physician might wrongly think there is adenomyosis. This might be because another lesion (e.g. a uterine fibroid) mimics an adenomyosis lesion. Furthermore, TVUS is intrusive and can also be quite painful for some subjects. MRI is the modality of choice following an inconclusive ultrasound, and can demonstrate wall thickening of the uterus. However, both TVUS and MRI suffer from poor inter-observer reproducibility. Consequently, an integrated approach, considering risk factor profile, clinical symptoms, clinical examination and non- invasive imaging, is employed to diagnose adenomyosis. Due to uncertainties in imaging, laparoscopic surgery may ultimately be required for definitive diagnosis. The present invention provides a non-invasive, radiopharmaceutical imaging method to assist in the diagnosis of adenomyosis.99mTc-maraciclatide undergoes rapid clearance in vivo, which helps reduce radiation dose to the patient, as well as being favourable for imaging. Biodistribution of99mTc-maraciclatide into the tissues / organs in the vicinity of the uterus (excluding the bladder) is slow, providing a broad time window for uterine imaging. Since it uses the generator-produced radioisotope99mTc, together with a non-radioactive kit for the preparation of99mTc-maraciclatide, the radiopharmaceutical itself is expected to be widely-available. Similarly, since99mTc is a gamma-emitting radioisotope long-established in nuclear medicine, there is an extensive installed base of suitable gamma cameras for the imaging of the invention. Use of the ubiquitous99mTc radionuclide thus provides broad access to diagnosis, which should shorten significantly the average time between symptom onset and final diagnosis, enabling earlier treatment, hence reducing the need for surgical intervention. The99mTc-maraciclatide radiopharmaceutical uses a standardised imaging procedure – with the result that successful scanning is not dependent upon 2025.05.09 Specification – P000705WO 7 the skill of the operator.99mTc-maraciclatide has been shown to be safe in a human volunteer study [Gibbons et al, Nucl.Med.Comm., 45, 295-303 (2024)]. Furthermore, both TVUS and MRI provide anatomical rather than functional information. The99mTc-maraciclatide radiopharmaceutical of the present invention provides more functional information, since it is a marker of angiogenesis and inflammation – and hence locations of active tissue growth or inflammation and early disease where treatment is likely to be more effective. In addition, adenomyosis frequently occurs together with endometriosis in the same subject, and the conditions share similar signs and symptoms. There is therefore a need for a non-invasive imaging method useful in the diagnosis of adenomyosis, and in confirming adenomyosis over endometriosis. The present method also assists in identifying women who do not have active adenomyosis, and hence individuals where alternative diagnoses need to be pursued. An accurate and timely diagnosis of adenomyosis would lead to earlier initiation of appropriate treatment and potentially improved long-term outcomes. This would also reduce the negative impact of undiagnosed and untreated adenomyosis on women’s lives. Detailed Description of the Invention. In a first aspect, the present invention provides a method of imaging adenomyosis in a subject, which comprises prior administration of the radiopharmaceutical99mTc- maraciclatide to said subject, followed by pelvic imaging of the radioactive emissions from said99mTc-maraciclatide in vivo. The term “adenomyosis” has its conventional meaning, and refers to a benign gynaecological condition where tissue from the lining of the uterus (i.e. the endometrium) grows into the muscle wall (or myometrium) of the mammalian uterus. In contrast, the term “endometriosis” has its’ conventional meaning, and refers to a gynaecological disorder of the female reproductive system, characterised by the presence of abnormal (i.e. ectopic, out of place), proliferating endometrial cells outside the uterus. 2025.05.09 Specification – P000705WO 8 By the term “pelvic imaging” is meant that the region of interest (ROI) for radiopharmaceutical imaging is focused on the pelvis of the subject, including the uterus of the subject. Preferably, said imaging focuses on uterine imaging. Thus, the imaging of the first aspect assists in the confirmation of the presence or absence of adenomyosis in the subject. It therefore assists in identifying subjects who are suffering from either: (a) adenomyosis alone; (b) both adenomyosis and endometriosis; or (c) neither adenomyosis nor endometriosis. This can affect patient management and treatment, as described in the second and third aspects (below). Thus, the uptake of99mTc-maraciclatide into lesions differs between the two conditions. In subjects with adenomyosis, uptake is seen within the uterus whereas in subjects with endometriosis, uptake is seen as focal uptake elsewhere within the pelvis (e.g. pouch of Douglas, pelvic walls, sigmoid colon or bladder) or outside the pelvis (e.g. lungs) and / or on the surface of the uterus. Preferably, the imaging of the first aspect helps distinguish adenomyosis from endometriosis – i.e. it differentiates those subjects suffering from adenomyosis and not endometriosis. Alternatively, said imaging can also preferably differentiate subjects suffering from both adenomyosis and endometriosis. The terms “comprising” or “comprises” have their conventional meaning throughout this application and imply that the composition must have the components listed, but that other, unspecified compounds or species may be present in addition. The term ‘comprising’ includes as a preferred subset “consisting essentially of” which means that the composition has the components listed without other compounds or species being present. The term “subject” refers to an intact mammalian body with a uterus in vivo, preferably a human female patient, more preferably a human female of reproductive to post-menopausal age, most preferably a human female of reproductive age.99mTc is the radioisotope Technetium-99m, which decays with a half-life of 6.02 hours to technetium-99 (99Tc). The radioactive decay is accompanied by the emission of a gamma ray with a photon energy of 140 keV that is near ideal for medical imaging. It is these gamma rays that are the “radioactive emissions” of the first aspect.99mTc and99mTc-radiopharmaceuticals are well known in the art, and99mTc is readily available from commercially-available Technetium-99m generators. It can also be produced in 2025.05.09 Specification – P000705WO 9 cyclotrons by irradiation of99Mo or100Mo.99mTc radiopharmaceuticals, methods of imaging and associated kits are described in Technetium-99m Pharmaceuticals: Preparation and Quality Control in Nuclear Medicine, I. Zolle (Ed), Springer (2006). Maraciclatide is the recommended INN (USA Approved Name) for NC100692. The term “maraciclatide” refers to the compound known in the scientific literature as NC100692 [D.Edwards et al, Nucl.Med.Biol., 35, 365-375 (2008)]. The chemical structure of maraciclatide is as follows: Maraciclatide Maraciclatide is a bicyclic RGD (Arg-Gly-Asp) peptide, having conjugated thereto a diaminedioxime chelating agent. The chelating agent forms a metal complex with the technetium radiometal, which is a neutral technetium complex. Maraciclatide can be used in the free base form, or in the salt form (e.g. the trifluoroacetate). The syntheses of maraciclatide,99mTc-maraciclatide and kits for the preparation of99mTc-maraciclatide are given in the present Examples. The term “radiopharmaceutical” has its conventional meaning, and refers to a radioactive compound in a form suitable for in vivo mammalian administration for use in diagnosis or therapy. By the phrase “in a form suitable for mammalian administration” is meant a composition which is sterile, pyrogen-free, lacks compounds which produce toxic or adverse effects, and is formulated at a biocompatible pH (approximately pH 4.0 to 10.5, preferably 6.5 to 9.5 for the agent of the present invention) and physiologically compatible osmolality. Such compositions 2025.05.09 Specification – P000705WO 10 lack particulates which could risk causing emboli in vivo, and are formulated so that precipitation does not occur on contact with biological fluids (e.g. blood). Such compositions also contain only biologically compatible excipients, and are preferably isotonic.The 99mTc-maraciclatide radiopharmaceutical of the present invention is provided in abiocompatible carrier. The “biocompatible carrier” is a fluid, especially a liquid, in which the radiopharmaceutical can be suspended or preferably dissolved, such that the composition is physiologically tolerable, i.e. can be administered to the mammalian body without toxicity or undue discomfort. The biocompatible carrier is suitably an injectable carrier liquid such as sterile, pyrogen-free water for injection; an aqueous solution such as saline (which may advantageously be balanced so that the final product for injection is isotonic); an aqueous buffer solution comprising a biocompatible buffering agent (e.g. phosphate buffer); an aqueous solution of one or more tonicity-adjusting substances (e.g. salts of plasma cations with biocompatible counterions), sugars (e.g. glucose or sucrose), sugar alcohols (e.g. sorbitol or -- mannitol), glycols (e.g. glycerol), or other non-ionic polyol materials (e.g. polyethyleneglycols, propylene glycols and the like). Preferably the biocompatible carrier is pyrogen-free water for injection, isotonic saline or phosphate buffer. The radiopharmaceutical composition is suitably provided in a pharmaceutical grade container. A preferred such container is a septum-sealed vial, wherein the gas-tight closure is crimped on with an overseal (typically of aluminium). The closure is suitable for single or multiple puncturing with a hypodermic needle (e.g. a crimped-on septum seal closure) whilst maintaining sterile integrity. Such containers have the additional advantage that the closure can withstand vacuum if desired (e.g. to change the headspace gas or degas solutions), and withstand pressure changes such as reductions in pressure without permitting ingress of external atmospheric gases, such as oxygen or water vapour. Preferred multiple dose containers comprise a single bulk vial (e.g. of 6 to 30 cm3volume) which contains multiple patient doses, whereby single patient doses can thus be withdrawn into clinical grade syringes at various time intervals during the viable lifetime of the preparation to suit the clinical situation. 2025.05.09 Specification – P000705WO 11 The radiopharmaceutical composition may also be provided in a syringe. Pre-filled syringes are designed to contain a single human dose, or “unit dose” and are therefore preferably a single-use or other syringe suitable for clinical use. The term “prior administration” refers to the fact that the99mTc-maraciclatide radiopharmaceutical is administered to the subject before the imaging of the first aspect is carried out. Preferably, the99mTc-maraciclatide radiopharmaceutical is administered to the subject in a minimally invasive manner, i.e. without a substantial health risk to the mammalian subject even when carried out under professional medical expertise. Such minimally invasive administration is preferably intravenous administration into a peripheral vein of said subject, without the need for local or general anaesthetic. In the method of the first aspect, the radioactive emissions are preferably detected and processed using: a conventional or high resolution gamma camera; a gamma detector; image processing software or combinations thereof. Conventional gamma cameras or ‘Anger cameras’ typically comprise a sodium iodide scintillator crystal coupled to an array of photomultiplier tubes. The imaging preferably employs a gamma camera, for either planar or tomographic imaging. More preferably, said imaging is tomographic imaging and comprises SPECT imaging. Most preferably, said imaging comprises SPECT imaging with CT (SPECT-CT) for attenuation correction and anatomical identification. In the present invention, the gamma camera is preferably a high-resolution gamma camera capable of 360-degree imaging, ideally with sub-millimetre spatial resolution. The gamma camera is most preferably a high-resolution gamma camera which comprises a CZT detector. The “CZT detector” is a Cd-Zn-Te or cadmium-zinc- telluride solid state detector, and suitable such cameras equipped with CZT detectors are commercially available as Veriton CT, D-SPECT (Spectrum Dynamics Medical, Israel) or Starguide / Discovery NM / CT 870 CZT, NM 530c (GE Healthcare). The imaging typically commences 1 minute to 12-hours after administration of the radiopharmaceutical of the invention, with image acquisition for 5 to 45 minutes, preferably 10-30 minutes by planar scintigraphy, SPECT or SPECT-CT. Further information on radiopharmaceutical emission detection for medical imaging and / or 2025.05.09 Specification – P000705WO 12 diagnosis is given in the second aspect (below). The sensitivity of the CZT detector permits effective imaging with lower doses of radiopharmaceutical, thus reducing the radiation burden to the subject. The CZT detector also provides improved resolution over conventional SPECT imaging. In the method of the first aspect, the99mTc-maraciclatide radiopharmaceutical is suitably prepared by reaction of maraciclatide with99mTc-pertechnetate in the presence of a reducing agent suitable for reducing pertechnetate, as is known in the art for technetium radiopharmaceuticals. The99mTc-maraciclatide radiopharmaceutical is preferably prepared by reconstitution of a maraciclatide kit. That is because99mTc- maraciclatide, once prepared, has a 6-hour half-life, so 50% of the usable activity for imaging is lost every 6-hours (i.e. a limited time for use), and requires radioactive safety handling precautions. The term “kit” has its conventional meaning in the field of technetium-99m radiopharmaceuticals, and refers to one or more pharmaceutical grade containers, comprising the necessary non-radioactive chemicals to prepare the desired radiopharmaceutical composition, together with operating instructions. The kit is designed to be reconstituted with99mTc, especially as pertechnetate, to give a solution suitable for human administration with the minimum of manipulation. Preferably, the kit is suitable for the preparation of the99mTc-radiopharmaceutcial at ambient temperature. The kit of the present invention preferably comprises a lyophilised composition containing all the kit components in a single lyophilised formulation in a single container. The kit is non-radioactive (and is hence sometimes described as a ‘cold kit’), has a usable shelf-life of several months, and can be used to prepare99mTc- maraciclatide in minutes. Due to the convenience of the kit, long-established commercial practice in the field of99mTc radiopharmaceuticals is to commercialise the kit, rather than the radioactive99mTc radiopharmaceutical itself. The term “maraciclatide kit” thus has its conventional meaning in the field of99mTc radiopharmaceuticals, and refers to a non-radioactive kit containing at least maraciclatide and a reducing agent for pertechnetate. The maraciclatide kit is used solely to obtain the99mTc-maraciclatide radiopharmaceutical, in a form suitable for human administration. Consequently, the maraciclatide kit is preferably sterile, and is 2025.05.09 Specification – P000705WO 13 most preferably lyophilised. Said kit may comprise one or more vials, but is preferably a single vial containing all the necessary components, more preferably when all the kit components are lyophilised together in a single vial. The kit is designed to be reconstituted with sterile99mTc-pertechnetate (TcO4-) from a99mTc radioisotope generator to give a solution suitable for human administration without further manipulation. The maraciclatide kit is designed to be reconstituted with99mTc-pertechnetate once only. The maraciclatide kit most preferably comprises: a) maraciclatide; b) para-aminobenzoic acid or a salt thereof with a biocompatible cation; c) a stannous reductant; d) methylene diphosphonic acid or a salt thereof with a biocompatible cation. para-Aminobenzoic acid is commercially available, including in pharmaceutical grade purity. Preferably, pharmaceutical grade material is used. By the term “biocompatible cation” is meant a positively charged counterion which forms a salt with an ionised, negatively charged group, where said positively charged counterion is also non-toxic and hence suitable for administration to the mammalian body, especially the human body. Examples of suitable biocompatible cations include: the alkali metals sodium or potassium; the alkaline earth metals calcium and magnesium; and the ammonium ion. Preferred biocompatible cations are sodium and potassium, most preferably sodium. Most preferably, the para-aminobenzoic acid salt of the present invention consists essentially of sodium para-aminobenzoate. The term “stannous reductant” has its conventional meaning in the field of99mTc radiopharmaceuticals and kits, and refers to a salt of Sn2+, i.e. tin in the Sn(II) oxidation state. Suitable such salts may be in the hydrated or anhydrous form, and include: stannous chloride, stannous fluoride and stannous tartrate. A preferred such stannous reductant is stannous chloride. The term “methylene diphosphonic acid” has its conventional chemical meaning, and is abbreviated MDP. The maraciclatide kit preferably further comprises a buffer which comprises a mixture of sodium hydrogen carbonate and anhydrous sodium carbonate. 2025.05.09 Specification – P000705WO 14 A most preferred maraciclatide kit has the formulation as follows (Example 7): Component Quantity per vial Maraciclatide 75μg Stannous chloride dihydrate 17.8 μg Methylene diphosphonic acid (MDP) 90 μg Para-aminobenzoic acid 200 μg (pABA), sodium salt Sodium hydrogen carbonate 1800 μg Sodium carbonate anhydrous 630 μg The method of imaging of the first aspect is useful in the diagnosis of adenomyosis, but is not the complete diagnosis. That is because the radiopharmaceutical images obtained would need one or more of: (a) comparison with normal, i.e. disease-free images; (b) interpretation by a clinical expert, or (c) analysis by suitable computerised algorithms or artificial intelligence – alone or in combinations thereof. That diagnostic method is addressed in the second aspect below. In a second aspect, the present invention provides a method of diagnosis of adenomyosis which comprises the method of imaging as defined in the first aspect. Preferred aspects of the adenomyosis imaging and distinguishing adenomyosis from endometriosis, subject; radioactive emissions detection; the99mTc-maraciclatide radiopharmaceutical; the method of preparation of99mTc-maraciclatide and non- radioactive kit in the second aspect are all as described in the first aspect (above). The method of diagnosis of the second aspect includes the step of administration of the99mTc-maraciclatide radiopharmaceutical to the subject. The imaging of the first aspect provides medical images. The data from the imaging of the subject using a suitable gamma camera or gamma detector is processed by algorithms as is known in the art to produce medical images. Gamma camera, gamma detectors and image processing are reviewed in: Handbook of Nuclear Medicine and Molecular Imaging for Physicists, M.Ljungberg (Ed), 3 volume set, CRC Press (2021). Image interpretation for a given subject is then achieved by options A and B: 2025.05.09 Specification – P000705WO 15 Option A (i) review of the images by a radiologist; (ii) qualitative or quantification scoring of radiopharmaceutical uptake in a region of interest (ROI); (iii) decision by the radiologist or clinical team as to whether to proceed to instigate a course of treatment or exclude adenomyosis from the diagnosis, and pursue alternative avenues. Option B (i) image analysis using one or more machine learning derived algorithms to highlight lesions in a ROI; (ii) review of the images by a radiologist; (iii) decision by radiologist or clinical team as to whether to instigate a course of treatment or rule out adenomyosis from the diagnosis, and pursue alternative avenues. In both options A and B, the radiologist may optionally use reference to one or more normal scans. By the term “normal scan” is meant at least one reference image using the same radiopharmaceutical, and preferably the same gamma camera, means of detection and image processing methodology in a different subject, where no adenomyosis was found. More than one such normal scan may be used as a library of images, to assist with normal variation in images. Thus, laparoscopic surgery when utilised, would be to obtain a confirmatory diagnosis, especially when used in conjunction with biopsy which would permits clinical characterisation of the lesion, and thus assist in the determination of subsequent patient management or treatment. In a third aspect, the present invention provides a method of determination of therapy of adenomyosis in a subject, which comprises the method of imaging of the first aspect or the method of diagnosis of the second aspect. In the third aspect, preferred aspects of the: adenomyosis imaging and distinguishing adenomyosis from endometriosis; subject; radioactive emissions detection; the99mTc-maraciclatide radiopharmaceutical; method of preparation of99mTc-maraciclatide; and non- radioactive kit in the third aspect are as described in the first aspect (above). 2025.05.09 Specification – P000705WO 16 Preferred aspects of the method of diagnosis in the third aspect are as described in the second aspect. Differential diagnosis of adenomyosis to distinguish it from other diseases such as endometriosis represents a significant challenge and affects subsequent treatment. Hence, the present invention contributes to improved patient management and treatment. Thus, the treatment of endometriosis involves the use of combined hormonal contraceptives; progestins; and Gonadotropin-releasing hormone (GnRH) agonists / antagonists and surgical excision / ablation of lesions. In contrast, the question of how to treat adenomyosis to resolve the underlying condition is still unclear. Currently, the best available option is to attempt to moderate the symptoms of adenomyosis. In this regard, the Levonorgestrel intrauterine system is an effective treatment for adenomyosis-associated heavy menstrual bleeding and pain. Hysterectomy is the preferred surgical treatment in women who no longer desire pregnancy. The present invention provides the possibility of evaluating possible therapeutic options for adenomyosis, by seeing whether e.g. anti-angiogenic or anti- inflammatory drugs reduce uptake of99mTc-maraciclatide and hence indicate improvement in the underlying condition. The fourth aspect of this invention (below) refers to such therapy monitoring. Harmsen et al [Human Reprod. Update, 25(5), 647-671 (2019)] discuss how angiostatic drugs could potentially be used to treat adenomyosis. In this aspect, the imaging of the first aspect may confirm the presence of adenomyosis. That in itself may be enough information to help determine subsequent patient management or treatment. In other circumstances, the method of diagnosis of the second aspect is necessary. Knowledge of the extent (i.e. limited / focal or widespread throughout the myometrium) of disease may help determine the subsequent treatment or therapy – either surgical or medication or combinations thereof. 2025.05.09 Specification – P000705WO 17 In a fourth aspect, the present invention provides a method of monitoring of a therapy of adenomyosis in a subject, which comprises the method of imaging of the first aspect or the method of diagnosis of the second aspect. In the fourth aspect, preferred aspects of the: adenomyosis imaging and distinguishingadenomyosis from endometriosis; subject; radioactive emissions detection; the 99mTc-maraciclatide radiopharmaceutical; method of preparation of99mTc-maraciclatide; and non-radioactive kit in the third aspect are as described in the first aspect (above). Preferred aspects of the method of diagnosis in the fourth aspect are as described in the second aspect (above). By the term “monitoring” is meant carrying out multiple imaging of the same subject before and at chosen time intervals during a course of therapy. Comparison of these images qualitatively or quantitatively then provides the clinician with information as to whether the therapy is reducing the degree of adenomyosis in the ROI for said subject or whether the attempted therapy is proving ineffective by allowing existing disease to progress, or new lesions to develop. The method of imaging or diagnosis of the invention is thus expected to help determine whether a given course of therapy is proving successful for the individual subject. If a positive result is found, then later images may be used to confirm the progression of therapy. If negative, then alternative therapies may be chosen and a new monitoring as per this fourth aspect of the invention initiated. In a fifth aspect, the present invention provides the use of99mTc-maraciclatide or a maraciclatide kit in one or more of the following: (i) the method of imaging of the first aspect, (ii) the method of diagnosis of the second aspect; (iii) the method of determination of therapy of the third aspect; (iv) the method of monitoring of therapy of the fourth aspect; wherein said maraciclatide kit is for the preparation of99mTc-maraciclatide, and is as defined in the first aspect. 2025.05.09 Specification – P000705WO 18 The term “maraciclatide kit”, and preferred embodiments thereof in this fifth aspect, are as defined in the first aspect (above). This fifth aspect also includes99mTc-maraciclatide or a maraciclatide kit for use in one or more of the methods (i)-(iv). In particular, the fifth aspect includes99mTc- maraciclatide for use in a method of diagnosis of adenomyosis, wherein said method of diagnosis comprises the method of imaging of the first aspect. Preferred aspects of the adenomyosis imaging and distinguishing adenomyosis from endometriosis; subject; radioactive emissions detection; method of preparation of99mTc-maraciclatide and non-radioactive kit in the fifth aspect are as described in the first aspect (above). In the fifth aspect, the kit is used in a method of preparation of the99mTc- maraciclatide radiopharmaceutical, which is then used in one or more of the methods (i)-(iv). Hence, within the scope of this aspect are any of the methods (i)-(iv) where the non-radioactive kit is used to provide the maraciclatide and / or99mTc- maraciclatide. In a sixth aspect, the present invention provides the use of a gamma camera, gamma detector and / or image processing software in one or more of the following: (i) the method of imaging of the first aspect, (ii) the method of diagnosis of the second aspect; (iii) the method of determination of therapy of the third aspect; (iv) the method of monitoring of therapy of the fourth aspect; In the sixth aspect, preferred aspects of the: adenomyosis imaging and distinguishing adenomyosis from endometriosis; subject; radioactive emissions detection, method of preparation of99mTc-maraciclatide and non-radioactive kit are as described in the first aspect (above). In the sixth aspect, the phrase “image processing software” includes algorithms, in particular artificial intelligence algorithms – especially machine learning adapted to 2025.05.09 Specification – P000705WO 19 work with99mTc-maraciclatide images. Gamma camera, gamma detectors and such image processing is reviewed in: Handbook of Nuclear Medicine and Molecular Imaging for Physicists, M.Ljungberg (Ed), 3 volume set, CRC Press (2021). Artificial intelligence in medical imaging has been reviewed by Seah et al [Br.J.Radiol., 94(1126), 20210406 (2021)]. Machine learning in medical imaging has been described by T. Sadad et al [Curr.Med.Imaging, 17(6), 686-694 (2021)]. In a further aspect, the present invention provides the radiopharmaceutical99mTc- maraciclatide for use in an in vivo imaging diagnostic method of adenomyosis in a subject. In this further aspect, the definitions of terms and preferred embodiments thereof are as described in the first and second aspects (above). The invention is illustrated by the non-limiting Examples detailed below. Examples 1 to 3 provide the synthesis of Chelator 1 (also called carba-Pn216) of the invention. Example 4 provides the synthesis of Chelator 1A of the invention – an active ester- functionalised version of Chelator 1. Example 5 provides the synthesis of cyclic peptides of the invention and chelator conjugation. Example 6 provides the synthesis of maraciclatide. Example 7 provides the preparation of a maraciclatide lyophilised kit. Example 8 provides the method of reconstituting the kit to obtain the99mTc- maraciclatide radiopharmaceutical. Example 9 provides a human imaging study showing uterine imaging of adenomyosis, which was confirmed by subsequent laparoscopic surgery. In subjects without adenomyosis, no pelvic99mTc signal was observed above background. Description of the Figures. Figure 1 provides a SPECT image showing99mTc-maraciclatide uptake in the uterus of a patient (cross-hairs) with adenomyosis confirmed by laparoscopic surgery. Black and white colour scheme, associated CT image not included. Review of the image showed uptake throughout the uterus, as well as other pelvic uptake associated with endometriosis. Following surgery, adenomyosis was seen as well as an endometrioma. Figure 2 provides a SPECT image showing99mTc-maraciclatide uptake in the uterus of a patient (cross-hairs) with adenomyosis confirmed by laparoscopic surgery. 2025.05.09 Specification – P000705WO 20 Alternative graded colour scheme rendered in black and white, associated CT image not included. Abbreviations. Conventional single letter or 3-letter amino acid abbreviations are used. Ac: Acetyl. Boc: tert-Butyloxycarbonyl. tBu: tertiary-butyl. CZT: cadmium-zinc-telluride. DIE: deep infiltrating endometriosis. DMF: Dimethylformamide. DMSO: Dimethylsulfoxide. Fmoc: 9-Fluorenylmethoxycarbonyl. HATU: O-(7-Azabenzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate. HBTU: O-Benzotriazol-1-yl-N,N,N',N'-tetramethyluronium hexafluorophosphate HPLC: High performance liquid chromatography. MDP: methylene diphosphonic acid. MRI: Magnetic Resonance Imaging. NMM: N-Methylmorpholine. pABA: para-amino-benzoic acid sodium salt PBS: Phosphate-buffered saline PEG: polyethyleneglycol, repeat units of (OCH2CH2)n, where n is an integer, PET: positron emission tomography. RCP: radiochemical purity. ROI: region of interest. RP-HPLC: reversed-phase HPLC. SPECT: Single Photon Emission Computer Tomography. SPECT-CT - Single Photon Emission Computer Tomography- Computer Tomography. TFA: Trifluoroacetic acid THF: Tetrahydrofuran. TIS: Triisopropylsilane TLC: thin layer chromatography Trt: Trityl. TVUS: trans-vaginal ultrasound. 2025.05.09 Specification – P000705WO 21 Compounds of the Invention. Compound Structure Chelator 1 Chelator 1A Example 1: Synthesis of 1,1,1-Tris(2-aminoethyl)methane. Step 1(a): 3(methoxycarbonylmethylene)glutaric acid dimethylester. Carbomethoxymethylenetriphenylphosphorane (167g, 0.5mol) in toluene (600ml) was treated with dimethyl 3-oxoglutarate (87g, 0.5mol) and the reaction heated to 100°C on an oil bath at 120 °C under an atmosphere of nitrogen for 36h. The reaction was then concentrated in vacuo and the oily residue triturated with 40 / 60 petrol ether / diethylether (1:1, 600 ml). Triphenylphosphine oxide precipitated out and the supernatant liquid was decanted / filtered off. The residue on evaporation in vacuo was Kugelrohr distilled under high vacuum Bpt (oven temperature 180-200°C at 0.2 torr) to give 3-(methoxycarbonylmethylene)glutaric acid dimethylester (89.08g, 53%). NMR1H(CDCl3): δ 3.31 (2H, s, CH2), 3.7(9H, s, 3xOCH3), 3.87 (2H, s, CH2), 5.79 (1H, s, =CH, ) ppm. NMR13C(CDCl3), δ 36.56,CH3, 48.7, 2xCH3, 52.09 and 52.5 (2xCH2); 122.3 and 146.16 C=CH; 165.9, 170.0 and 170.53xCOO ppm. Step 1(b): Hydrogenation of 3-(methoxycarbonylmethylene)glutaric acid dimethylester. 3-(Methoxycarbonylmethylene)glutaric acid dimethylester (89g, 267mmol) in methanol (200ml) was shaken with (10% palladium on charcoal: 50% water) (9 g) under an atmosphere of hydrogen gas (3.5 bar) for 30h. The solution was filtered 2025.05.09 Specification – P000705WO 22 through kieselguhr and concentrated in vacuo to give 3- (methoxycarbonylmethyl)glutaric acid dimethylester as an oil, yield (84.9g, 94 %). NMR1H(CDCl3), δ 2.48 (6H, d, J=8Hz, 3xCH2), 2.78 (1H, hextet, J=8Hz CH, ) 3.7 (9H, s, 3xCH3). NMR13C(CDCl3), δ 28.6, CH; 37.50, 3xCH3; 51.6, 3xCH2; 172.28,3 x COO. Step 1(c): Reduction and esterification of trimethyl ester to the triacetate. Under an atmosphere of nitrogen in a 3 necked 2L round bottomed flask lithium aluminium hydride (20g, 588 mmol) in THF (400ml) was treated cautiously with tris(methyloxycarbonylmethyl)methane (40g, 212 mmol) in THF (200ml) over 1h. A strongly exothermic reaction occurred, causing the solvent to reflux strongly. The reaction was heated on an oil bath at 90°C at reflux for 3 days. The reaction was quenched by the cautious dropwise addition of acetic acid (100ml) until the evolution of hydrogen ceased. The stirred reaction mixture was cautiously treated with acetic anhydride solution (500ml) at such a rate as to cause gentle reflux. The flask was equipped for distillation and stirred and then heating at 90°C (oil bath temperature) to distil out the THF. A further portion of acetic anhydride (300ml) was added, the reaction returned to reflux configuration and stirred and heated in an oil bath at 140°C for 5h. The reaction was allowed to cool and filtered. The aluminium oxide precipitate was washed with ethyl acetate and the combined filtrates concentrated on a rotary evaporator at a water bath temperature of 50°C in vacuo (5 mmHg) to afford an oil. The oil was taken up in ethyl acetate (500ml) and washed with saturated aqueous potassium carbonate solution. The ethyl acetate solution was separated, dried over sodium sulfate, and concentrated in vacuo to afford an oil. The oil was Kugelrohr distilled in high vacuum to give tris(2-acetoxyethyl)methane (45.3g, 95.9%) as an oil. Bp. 220 ºC at 0.1 mmHg. NMR1H(CDCl3), δ 1.66(7H, m, 3xCH2, CH), 2.08(1H, s, 3xCH3); 4.1(6H, t, 3xCH2O).NMR 13C(CDCl3), δ 20.9, CH3; 29.34, CH; 32.17, CH2; 62.15, CH2O; 171, CO.Step 1(d): Removal of Acetate groups from the triacetate. Tris(2-acetoxyethyl)methane (45.3g, 165mM) in methanol (200ml) and 880 ammonia (100ml) was heated on an oil bath at 80°C for 2 days. The reaction was treated with a further portion of 880 ammonia (50ml) and heated at 80°C in an oil bath for 24h. A further portion of 880 ammonia (50ml) was added and the reaction heated at 80°C for 24h. The reaction was then concentrated in vacuo to remove all solvents to give an 2025.05.09 Specification – P000705WO 23 oil. This was taken up into 880 ammonia (150ml) and heated at 80°C for 24h. The reaction was then concentrated in vacuo to remove all solvents to give an oil. Kugelrohr distillation gave acetamide bp 170-1800.2mm. The bulbs containing the acetamide were washed clean and the distillation continued. Tris(2- hydroxyethyl)methane (22.53g, 92%) distilled at bp 220 °C 0.2mm. NMR1H(CDCl3), δ 1.45(6H, q, 3xCH2), 2.2(1H, quintet, CH); 3.7(6H, t 3xCH2OH); 5.5(3H, brs, 3xOH). NMR13C(CDCl3), δ 22.13, CH; 33.95, 3xCH2; 57.8, 3xCH2OH. Step 1(e): Conversion of the triol to the tris(methanesulfonate). To an stirred ice-cooled solution of tris(2-hydroxyethyl)methane (10g, 0.0676mol) in dichloromethane (50ml) was slowly dripped a solution of methanesulfonyl chloride (40g, 0.349mol) in dichloromethane (50ml) under nitrogen at such a rate that the temperature did not rise above 15°C. Pyridine (21.4g, 0.27mol, 4eq) dissolved in dichloromethane (50ml) was then added drop-wise at such a rate that the temperature did not rise above 15°C, exothermic reaction. The reaction was left to stir at room temperature for 24h and then treated with 5N hydrochloric acid solution (80ml) and the layers separated. The aqueous layer was extracted with further dichloromethane (50ml) and the organic extracts combined, dried over sodium sulfate, filtered and concentrated in vacuo to give tris[2-(methylsulfonyloxy)ethyl]methane contaminated with excess methanesulfonyl chloride. The theoretical yield was 25.8g. NMR1H(CDCl3), δ 4.3 (6H, t, 2xCH2), 3.0 (9H, s, 3xCH3), 2 (1H, hextet, CH), 1.85 (6H, q, 3xCH2). Step 1(f): Preparation of 1,1,1-tris(2-azidoethyl)methane. A stirred solution of tris[2-(methylsulfonyloxy)ethyl]methane [from Step 1(e), contaminated with excess methylsulfonyl chloride] (25.8g, 67mmol, theoretical) in dry DMF (250ml) under nitrogen was treated with sodium azide (30.7g, 0.47mol) portion-wise over 15 minutes. An exotherm was observed and the reaction was cooled on an ice bath. After 30 minutes, the reaction mixture was heated on an oil bath at 50°C for 24h. The reaction became brown in colour. The reaction was allowed to cool, treated with dilute potassium carbonate solution (200ml) and extracted three times with 40 / 60 petrol ether / diethylether 10:1 (3x150ml). The organic extracts were washed with water (2x150ml), dried over sodium sulfate and filtered. Ethanol (200ml) was added to the petrol / ether solution to keep the triazide in 2025.05.09 Specification – P000705WO 24 solution and the volume reduced in vacuo to no less than 200ml. Ethanol (200ml) was added and reconcentrated in vacuo to remove the last traces of petrol leaving no less than 200ml of ethanolic solution. The ethanol solution of triazide was used directly in Step 1(g). CARE: DO NOT REMOVE ALL THE SOLVENT AS THE AZIDE IS POTENTIALLY EXPLOSIVE AND SHOULD BE KEPT IN DILUTE SOLUTION AT ALL TIMES. Less than 0.2ml of the solution was evaporated in vacuo to remove the ethanol and an NMR run on this small sample: NMR1H(CDCl3), δ 3.35 (6H, t, 3xCH2), 1.8 (1H, septet, CH,), 1.6 (6H, q, 3xCH2). Step 1(g): Preparation of 1,1,1-tris(2-aminoethyl)methane. Tris(2-azidoethyl)methane (15.06g, 0.0676 mol), (assuming 100% yield from previous reaction) in ethanol (200ml) was treated with 10% palladium on charcoal (2g, 50% water) and hydrogenated for 12h. The reaction vessel was evacuated every 2 hours to remove nitrogen evolved from the reaction and refilled with hydrogen. A sample was taken for NMR analysis to confirm complete conversion of the triazide to the triamine. Caution: unreduced azide could explode on distillation. The reaction was filtered through a celite pad to remove the catalyst and concentrated in vacuo to give tris(2- aminoethyl)methane as an oil. This was further purified by Kugelrohr distillation bp.180–200°C at 0.4mm / Hg to give a colourless oil (8.1g, 82.7% overall yield). NMR1H(CDCl3), δ 2.72 (6H, t, 3xCH2N), 1.41 (H, septet, CH), 1.39 (6H, q, 3xCH2). NMR13C(CDCl3), δ 39.8 (CH2NH2), 38.2 (CH2), 31.0 (CH). Example 2: Preparation of 3-Chloro-3-methyl-2-nitrosobutane. A mixture of 2-methylbut-2-ene (147ml, 1.4mol) and isoamyl nitrite (156ml, 1.16mol) was cooled to –30 °C in a bath of cardice and methanol and vigorously stirred with an overhead air stirrer and treated dropwise with concentrated hydrochloric acid (140ml, 1.68mol) at such a rate that the temperature was maintained below –20°C. This requires about 1h as there is a significant exotherm and care must be taken to prevent overheating. Ethanol (100ml) was added to reduce the viscosity of the slurry that had formed at the end of the addition and the reaction stirred at –20 to –10°C for a further 2h to complete the reaction. The precipitate was collected by 2025.05.09 Specification – P000705WO 25 filtration under vacuum and washed with 4x30ml of cold (-20°C) ethanol and 100ml of ice-cold water, and dried in vacuo to give 3-chloro-3-methyl-2-nitrosobutane as a white solid. The ethanol filtrate and washings were combined and diluted with water (200ml) and cooled and allowed to stand for 1h at –10°C when a further crop of 3- chloro-3-methyl-2-nitrosobutane crystallised out. The precipitate was collected by filtration and washed with the minimum of water and dried in vacuo to give 3-chloro- 3-methyl-2-nitrosobutane (115g 0.85mol, 73%) >98% pure by NMR. NMR1H(CDCl3), mixture of isomers (isomer1, 90%) 1.5 d, (2H, CH3), 1.65 d, (4H, 2 xCH3), 5.85,q, and 5.95,q, together 1H. (isomer2, 10%), 1.76 s, (6H, 2x CH3), 2.07(3H, CH3). Example 3: Synthesis of dimethyl-2-N-hydroxyimine propyl)2- aminoethyl]-(2- (Chelator 1). To a solution of tris(2-aminoethyl)methane (Example 1; 4.047g, 27.9mmol) in dry ethanol (30ml) was added potassium carbonate anhydrous (7.7g, 55.8mmol, 2eq) at room temperature with vigorous stirring under a nitrogen atmosphere. A solution of 3-chloro-3-methyl-2-nitrosobutane (Example 2; 7.56g, 55.8mol, 2eq) was dissolved in dry ethanol (100ml) and 75ml of this solution was dripped slowly into the reaction mixture. The reaction was followed by TLC on silica [plates run in dichloromethane, methanol, concentrated (0.88sg) ammonia; 100 / 30 / 5 and the TLC plate developed by spraying with ninhydrin and heating]. The mono-, di- and tri-alkylated products were seen with RF’s increasing in that order. Analytical HPLC was run using PRP reverse phase column in a gradient of 7.5-75% acetonitrile in 3% aqueous ammonia. The reaction was concentrated in vacuo to remove the ethanol and re-suspended in water (110ml). The aqueous slurry was extracted with ether (100ml) to remove some of the trialkylated compound and lipophilic impurities leaving the mono and desired dialkylated product in the water layer. The aqueous solution was buffered with ammonium acetate (2eq, 4.3g, 55.8mmol) to ensure good chromatography. The aqueous solution was stored at 4°C overnight before purifying by automated preparative HPLC. Yield (2.2g, 6.4mmol, 23%). Mass spec; Positive ion 10 V cone voltage. Found: 344; calculated M+H= 344. NMR1H(CDCl3), δ 1.24(6H, s, 2xCH3), 1.3(6H, s, 2xCH3), 1.25-1.75(7H, m, 3xCH2,CH), (3H, s, 2xCH2), 2.58 (4H, m, CH2N), 2.88(2H, t CH2N), 5.0 (6H, s, NH2, 2xNH, 2xOH). 2025.05.09 Specification – P000705WO 26 NMR1H ((CD3)2SO) δ 1.14xCH; 1.29, 3xCH2; 2.1 (4H, t, 2xCH2); NMR13C((CD3)2SO), δ 9.0 (4xCH3), 25.8 (2xCH3), 31.02xCH2, 34.6 CH2, 56.82xCH2N; 160.3, C=N. HPLC conditions: flow rate 8ml / min using a 25mm PRP column [A=3% ammonia solution (sp.gr = 0.88) / water; B = Acetonitrile]. Gradient Time (min) 0 15 20 22 30 % B 7.5 75.0 75.0 7.5 7.5 Load 3ml of aqueous solution per run, and collect in a time window of 12.5-13.5 min. Example 4: Synthesis of Tetrafluorothiophenyl ester of Chelator 1-glutaric acid (Chelator 1A). (Step 4a) Synthesis of [Chelator 1]-glutaric acid intermediate. Chelator 1 (100 mg, 0.29 mmol) was dissolved in DMF (10 ml) and glutaric anhydride (33 mg, 0.29 mmol) added by portions with stirring. The reaction was stirred for 23 hours to afford complete conversion to the desired product. The pure acid was obtained following RP-HPLC in good yield. (Step 4b) Synthesis of Chelator 1A. Chelator 1A To [Chelator 1]-glutaric acid (from Step 4a; 300 mg, 0.66 mmol) in DMF (2 ml) was added HATU (249 mg, 0.66 mmol) and NMM (132 µL, 1.32 mmol). The mixture was stirred for 5 minutes then tetrafluorothiophenol (0.66 mmol, 119 mg) was added. The solution was stirred for 10 minutes then the reaction mixture was diluted with 20 % acetonitrile / water (8 ml) and the product purified by RP-HPLC yielding 110 mg of the desired product following freeze-drying. 2025.05.09 Specification – P000705WO 27 Example 5: Synthesis of disulfide [Cys2-6] thioether cyclo[CH2CO-Lys(Chelator 1-glutaryl)-Cys2-Arg-Gly-Asp-Cys6-Phe-Cys]-NH2. (Step 5a) Synthesis of ClCH2CO-Lys-Cys(tBu)-Arg-Gly-Asp-Cys(tBu)-Phe-Cys- NH2 The peptide was synthesised on an ABI 433A automatic peptide synthesiser starting with Rink Amide AM resin on a 0.25 mmol scale using 1 mmol amino acid cartridges. The amino acids were pre-activated using HBTU before coupling. N-terminal amine groups were chloroacetylated using a solution of chloroacetic anhydride in DMF for 30 min. The simultaneous removal of peptide and side-chain protecting groups (except tBu) from the resin was carried out in TFA containing TIS (5 %), H2O (5 %) and phenol (2.5 %) for two hours. After work-up 295 mg of crude peptide was obtained (Analytical HPLC: Gradient, 5-50 % B over 10 min where A = H2O / 0.1 % TFA and B = CH3CN / 0.1 % TFA; column, Phenomenex Luna 3µ C18 (2) 50 x 4.6 mm; flow, 2 ml / min; detection, UV 214 nm; product retention time, 6.42 min). Further product characterisation was carried out using mass spectrometry: Expected, M+H at 1118.5, found, at 1118.6). 2025.05.09 Specification – P000705WO 28 (Step 5b) Synthesis of thioether Lys-Cys(tBu)-Arg-Gly-Asp-Cys(tBu)- Phe-Cys]-NH2. 295 mg of ClCH2CO-Lys-Cys(tBu)-Arg-Gly-Asp-Cys(tBu)-Phe-Cys-NH2was dissolved in water / acetonitrile. The mixture was adjusted to pH 8 with ammonia solution and stirred for 16 hours. After work-up 217 mg of crude peptide was obtained (Analytical HPLC: Gradient, 5-50 % B over 10 min where A = H2O / 0.1 % TFA and B = CH3CN / 0.1 % TFA; column, Phenomenex Luna 3µ C18 (2) 50 x 4.6 mm; flow, 2 ml / min; detection, UV 214 nm; product retention time, 6.18 min). Further product characterisation was carried out using mass spectrometry: Expected, M+H at 1882.5, found, at 1882.6). (Step 5c) Synthesis of disulfide [Cys2-6] thioether cyclo[CH2CO-Lys-Cys2-Arg-Gly- Asp-Cys6-Phe-Cys]-NH2. 217 mg of thioether cyclo[CH2CO-Lys-Cys(tBu)-Arg-Gly-Asp-Cys(tBu)-Phe-Cys]- NH2was treated with a solution of anisole (500 µL), DMSO (2 ml) and TFA (100 ml) for 60 min following which the TFA was removed in vacuo and the peptide precipitated by the addition of diethyl ether. Purification by preparative HPLC (Phenomenex Luna 10µ C18 (2) 250 x 50 mm column) of the crude material (202 mg) was carried out using 0-30 % B, where A = H2O / 0.1 % TFA and B = CH3CN / 0.1 % TFA, over 60 min at a flow rate of 50 ml / min. After lyophilisation 112 mg of pure material was obtained (Analytical HPLC: Gradient, 5-50 % B over 10 min where A = H2O / 0.1 % TFA and B = CH3CN / 0.1 % TFA; column, Phenomenex Luna 3µ C18 (2) 50 x 4.6 mm; flow, 2 ml / min; detection, UV 214 nm; product retention time, 5.50 2025.05.09 Specification – P000705WO 29 min). Further product characterisation was carried out using mass spectrometry: Expected, M+H at 968, found, at 971). (Step 5d) Synthesis of disulfide [Cys2-6] thioether cyclo[CH2CO-Lys(Chelator 1- glutaryl)-Cys2-Arg-Gly-Asp-Cys6-Phe-Cys]-NH2. Cys]-NH2, 9.1 mg of Chelator 1A (Example 5) and 6 µL of NMM was dissolved in DMF (0.5 ml). The mixture was stirred for 3 hours. Purification by preparative HPLC (Phenomenex Luna 5µ C18 (2) 250 x 21.20 mm column) of the reaction mixture was carried out using 0-30 % B, where A = H2O / 0.1 % TFA and B = CH3CN / 0.1 % TFA, over 40 min at a flow rate of 10 ml / min. After lyophilisation 5.7 mg of pure material was obtained (Analytical HPLC: Gradient, 0-30 % B over 10 min where A = H2O / 0.1 % TFA and B = CH3CN / 0.1 % TFA; column, Phenomenex Luna 3 µ C18 (2) 50 x 4.6 mm; flow, 2 ml / min; detection, UV 214 nm; product retention time, 7.32 min). Further product characterisation was carried out using mass spectrometry: Expected, M+H at 1407.7, found, at 1407.6). Example 6: Synthesis of disulfide [Cys2-6] thioether cyclo[CH2CO-Lys(Chelator 1-glutaryl)-Cys2-Arg-Gly-Asp-Cys6-Phe-Cys]-(PEG)3-NH2 (Maraciclatide). (Step 6a) Synthesis of 17-(Fmoc-amino)-5-oxo-6-aza-3,9,12,15- tetraoxaheptadecanoic acid. This building block is coupled to the solid-phase using Fmoc chemistry. 1,11-Diazido-3,6,9-trioxaundecane. 2025.05.09 Specification – P000705WO 30 A solution of dry tetraethyleneglycol (19.4 g, 0.100 mol) and methanesulfonyl chloride (25.2 g, 0.220 mol) in dry THF (100 ml) was kept under argon and cooled to 0 °C in an ice / water bath. To the flask was added a solution of triethylamine (22.6 g, 0.220 mol) in dry THF (25 ml) dropwise over 45 min. After 1 hr the cooling bath was removed and stirring was continued for 4 hrs. Water (60 ml) was added. To the mixture was added sodium hydrogen carbonate (6 g, to pH 8) and sodium azide (14.3 g, 0.220 mmol), in that order. THF was removed by distillation and the aqueous solution was refluxed for 24 h (two layers formed). The mixture was cooled and ether (100 ml) was added. The aqueous phase was saturated with sodium chloride. The phases were separated and the aqueous phase was extracted with ether (4 x 50 ml). Combined organic phases were washed with brine (2 x 50 ml) and dried (MgSO4). Filtration and concentration gave 22.1 g (91%) of yellow oil. The product was used in the next step without further purification. 11-Azido-3,6,9-trioxaundecanamine. To a mechanically, vigorously stirred suspension of 1,11-diazido-3,6,9- trioxaundecane (20.8 g, 0.085 mol) in 5% hydrochloric acid (200 ml) was added a solution of triphenylphosphine (19.9 g, 0.073 mol) in ether (150 ml) over 3 hrs at room temperature. The reaction mixture was stirred for additional 24 hrs. The phases were separated and the aqueous phase was extracted with dichloromethane (3 x 40 ml). The aqueous phase was cooled in an ice / water bath and pH was adjusted to ca 12 by addition of KOH. The product was extracted into dichloromethane (5 x 50 ml). Combined organic phases were dried (MgSO4). Filtration and evaporation gave 14.0 g (88%) of yellow oil. Analysis by MALDI-TOF mass spectroscopy (matrix: α- cyano-4-hydroxycinnamic acid) gave a M+H peak at 219 as expected. Further characterisation using1H (500 MHz) and13C (125 MHz) NMR spectroscopy verified the structure. 17-Azido-5-oxo-6-aza-3,9,12,15-tetraoxaheptadecanoic acid. To a solution of 11-azido-3,6,9-trioxaundecanamine (10.9 g, 50.0 mmol) in dichloromethane (100 ml) was added diglycolic anhydride (6.38 g, 55.0 mmol). The reaction mixture was stirred overnight. HPLC analysis (column Vydac 218TP54; solvents: A = water / 0.1% TFA and B = acetonitrile / 0.1% TFA; gradient 4-16% B over 20 min; flow 1.0 ml / min; UV detection at 214 and 284 nm), showed complete conversion of starting material to a product with retention time 18.3 min. The 2025.05.09 Specification – P000705WO 31 solution was concentrated to give quantitative yield of a yellow syrup. The product was analysed by LC-MS (ES ionisation) giving [MH]+ at 335 as expected.1H (500 MHz) and13C (125 MHz) NMR spectroscopy was in agreement with structure The product was used in the next step without further purification. 17-Amino-5-oxo-6-aza-3,9,12,15-tetraoxaheptadecanoic acid. A solution of 17-azido-5-oxo-6-aza-3,9,12,15-tetraoxaheptadecanoic acid (8.36 g, 25.0 mmol) in water (100 ml) was reduced using H2(g)-Pd / C (10%). The reaction was run until LC-MS analysis showed complete conversion of starting material (column Vydac 218TP54; solvents: A = water / 0.1% TFA and B = acetonitrile / 0.1% TFA; gradient 4-16% B over 20 min; flow 1.0 ml / min; UV detection at 214 and 284 nm, ES ionisation giving M+H at 335 for starting material and 309 for the product). The solution was filtered and used directly in the next step. 17-(Fmoc-amino)-5-oxo-6-aza-3,9,12,15-tetraoxaheptadecanoic acid. To the aqueous solution of 17-amino-5-oxo-6-aza-3,9,12,15-tetraoxaheptadecanoic acid from above (corresponding to 25.0 mmol amino acid) was added sodium bicarbonate (5.04 g, 60.0 mmol) and dioxan (40 ml). A solution of Fmoc-chloride (7.11 g, 0.275 mol) in dioxan (40 ml) was added dropwise. The reaction mixture was stirred overnight. Dioxan was evaporated off (rotavapor) and the aqueous phase was extracted with ethyl acetate. The aqueous phase was acidified by addition of hydrochloric acid and precipitated material was extracted into chloroform. The organic phase was dried (MgSO4), filtered and concentrated to give 11.3 g (85%) of a yellow syrup. The structure was confirmed by LC-MS analysis (column Vydac 218TP54; solvents: A = water / 0.1% TFA and B = acetonitrile / 0.1% TFA; gradient 40- 60% B over 20 min; flow 1.0 ml / min; UV detection at 214 and 254 nm, ES ionisation giving M+H at 531 as expected for the product peak at 5,8 minutes). The analysis showed very low content of side products and the material was used without further purification. (Step 6b) Synthesis of ClCH2CO-Lys-Cys(tBu)-Arg-Gly-Asp-Cys(tBu)-Phe-Cys- (PEG)3-NH2. 2025.05.09 Specification – P000705WO 32 The PEG unit was coupled manually to Rink Amide AM resin, starting on a 0.25 mmol scale, mediated by HATU activation. The remaining peptide was assembled on an ABI 433A automatic peptide synthesiser using 1 mmol amino acid cartridges. The amino acids were pre-activated using HBTU before coupling. N-terminal amine groups were chloroacetylated using a solution of chloroacetic anhydride in DMF for 30 min. The simultaneous removal of peptide and side-chain protecting groups (except tBu) from the resin was carried out in TFA containing TIS (5 %), H2O (5 %) and phenol (2.5 %) for two hours. After work-up 322 mg of crude peptide was obtained (Analytical HPLC: Gradient, 5-50 % B over 10 min where A = H2O / 0.1 % TFA and B = CH3CN / 0.1 % TFA; column, Phenomenex Luna 3µ C18 (2) 50 x 4.6 mm; flow, 2 ml / min; detection, UV 214 nm; product retention time, 6.37 min). Further product characterisation was carried out using mass spectrometry: Expected, M+H at 1409, found, at 1415). (Step 6c) Synthesis of thioether cyclo[CH2CO-Lys-Cys(tBu)-Arg-Gly-Asp-Cys(tBu)- Phe-Cys]-(PEG)3-NH2(NC100717). See Indrevoll et al [Bioorg.Med.Chem.Lett., 16, 6190-6193 (2006)]. 322 mg of ClCH2CO-Lys-Cys(tBu)-Arg-Gly-Asp-Cys(tBu)-Phe-Cys-(PEG)3-NH2was dissolved in water / acetonitrile. The mixture was adjusted to pH 8 with ammonia solution and stirred for 16 hours. After work-up, crude peptide was obtained (Analytical HPLC: Gradient, 5-50 % B over 10 min where A = H2O / 0.1 % TFA and B = CH3CN / 0.1 % TFA; column, Phenomenex Luna 3µ C18 (2) 50 x 4.6 mm; flow, 2 ml / min; detection, UV 214 nm; 2025.05.09 Specification – P000705WO 33 product retention time, 6.22 min). Further product characterisation was carried out using mass spectrometry: Expected, M+H at 1373, found, at 1378). (Step 6d) Synthesis of disulfide [Cys2-6] thioether cyclo[CH2CO-Lys-Cys2-Arg-Gly- Thioether cyclo[CH2CO-Lys-Cys(tBu)-Arg-Gly-Asp-Cys(tBu)-Phe-Cys]-(PEG)3-NH2was treated with a solution of anisole (200 µL), DMSO (2 ml) and TFA (100 ml) for 60 min following which the TFA was removed in vacuo and the peptide precipitated by the addition of diethyl ether. Purification by preparative HPLC (Phenomenex Luna 5µ C18 (2) 250 x 21.20 mm column) of 70 mg crude material was carried out using 0-30 % B, where A = H2O / 0.1 % TFA and B = CH3CN / 0.1 % TFA, over 40 min at a flow rate of 10 ml / min. After lyophilisation 46 mg of pure material was obtained (Analytical HPLC: Gradient, 0-30 % B over 10 min where A = H2O / 0.1 % TFA and B = CH3CN / 0.1 % TFA; column, Phenomenex Luna 3µ C18 (2) 50 x 4.6 mm; flow, 2 ml / min; detection, UV 214 nm; product retention time, 6.80 min). Further product characterisation was carried out using mass spectrometry: Expected, M+H at 1258.5, found, at 1258.8).

[0002] 2025.05.09 Specification – P000705WO 34 (Step 6e) Synthesis of disulfide [Cys2-6] thioether cyclo[CH2CO-Lys(Chelator 1- glutaryl)- 13 mg of 9.6 mg of Chelator 1A and 8 µL of NMM was dissolved in DMF (0.5 ml). The mixture was stirred for 2 hours and 30 minutes. Purification by preparative HPLC (Phenomenex Luna 5µ C18 (2) 250 x 21.20 mm column) of the reaction mixture was carried out using 0-30 % B, where A = H2O / 0.1 % TFA and B = CH3CN / 0.1 % TFA, over 40 min at a flow rate of 10 ml / min. After lyophilisation 14.2 mg of pure material was obtained (Analytical HPLC: Gradient, 0-30 % B over 10 min where A = H2O / 0.1 % TFA and B = CH3CN / 0.1 % TFA; column, Phenomenex Luna 3µ C18 (2) 50 x 4.6 mm; flow, 2 ml / min; detection, UV 214 nm; product retention time, 7.87 min). Further product characterisation was carried out using mass spectrometry: Expected, M+H at 1697.8, found, at 1697.9). A lyophilised kit was prepared having the following formulation: Component Quantity per vial ( g)Maraciclatide 75 Stannous chloride dihydrate 17.8 Methylene diphosphonic acid sodium salt 90 Para-amino-benzoic acid (pABA) sodium salt 200 Sodium hydrogen carbonate 1800 Sodium carbonate anhydrous 630 The Maraciclatide and excipients are dissolved in water for injection under a nitrogen atmosphere. Aliquots are dispensed into glass vials after sterile filtration and a synthetic rubber closure added. The solution is then frozen at -42oC and lyophilised 2025.05.09 Specification – P000705WO 35 under vacuum to remove the water. The lyophilised material is then closed under a nitrogen atmosphere and sealed with an aluminium overseal. The vials may be stored at 2-8oC for an extended period before use. Example 8: Preparation of99mTc-Maraciclatide. The kit of Example 7 was reconstituted with generator eluate of up to 3.1 GBq / 6 ml from a commercial Technetium Generator under aseptic conditions and allowed to stand at room temperature for 20 minutes. Quality Control is performed by both visual assessment and measurement of radiochemical purity (RCP) with thin layer chromatograph using silica coated paper and a mobile phase comprising 50:50 methanol and 1 molar ammonium acetate. The reconstituted solution is colourless and free from visible particles with RCP greater than 85%. Sufficient material to provide a patient dose is withdrawn into a syringe under aseptic conditions. Example 9: Imaging of Adenomyosis in Human Subjects. The99mTc-maraciclatide radiopharmaceutical was prepared as per Example 8. Each subject was given an intravenous injection of 740MBq99mTc-maraciclatide. SPECT / CT commenced within 30 minutes of injection. Image acquisition took 10 minutes using a Spectrum Dynamics Veriton 360 camera. The subject lay flat on the scanner bed for the duration of the scanning. A CT of the pelvis was acquired in parallel with SPECT imaging of99mTc uptake 30 minutes after administration of99mTc-maraciclatide. The raw SPECT data was reconstructed using a standardalgorithm that corrected for tissue density. The SPECT and CT images were reviewed separately and as a fused image to confirm position of uptake relative to organs. The image in Figure 1 shows the axial, sagittal and coronal views for the SPECT image from one representative subject. The image in Figure 2 shows the axial, sagittal and coronal views for the same representative subject using an alternative colour scheme rendered in black and white. Similar images were seen in several subjects in the same clinical study where adenomyosis diagnosis was supported by other data. Uterus uptake visualised by SPECT was absent in clinical subjects known not to have adenomyosis. The subject of Figure 1 and Figure 2 was aged 39, and was taking progesterone.

Claims

2025.05.09 Specification – P000705WO 36 CLAIMS.

1. A method of imaging adenomyosis in a subject, which comprises prior administration of the radiopharmaceutical99mTc-maraciclatide to said subject, followed by pelvic imaging of the radioactive emissions from said99mTc- maraciclatide in vivo.

2. The method of claim 1, where said imaging differentiates adenomyosis from endometriosis.

3. The method of claim 1, where said imaging differentiates subjects suffering from both adenomyosis and endometriosis.

4. The method of any one of claims 1 to 3, where the radioactive emissions are detected and processed using: a gamma camera; a gamma detector; image processing software or combinations thereof.

5. The method of any one of claims 1 to 4, where said imaging comprises a gamma camera with either planar or tomographic imaging.

6. The method of claim 5, where said imaging is tomographic imaging and comprises SPECT imaging.

7. The method of claim 6, where said imaging is SPECT-CT imaging.

8. The method of any one of claims 5 to 7, where the gamma camera is a high resolution gamma camera which comprises a CZT detector.

9. The method of any one of claims 1 to 8, where said99mTc-maraciclatide radiopharmaceutical is prepared by reaction of maraciclatide with99mTc-pertechnetate in the presence of a reducing agent.

10. The method of any one of claims 1 to 9, where said99mTc-maraciclatide radiopharmaceutical is prepared by reconstitution of a maraciclatide kit with a2025.05.09 Specification – P000705WO 37 solution of99mTc-pertechnetate, wherein said maraciclatide kit is non-radioactive, and comprises: a) maraciclatide; b) para-aminobenzoic acid or a salt thereof with a biocompatible cation; c) a stannous reductant; d) methylene diphosphonic acid or a salt thereof with a biocompatible cation.

11. A method of diagnosis of adenomyosis which comprises the method of imaging of any one of claims 1 to 10.

12. A method of determination of therapy of adenomyosis in a subject, which comprises the method of imaging of any one of claims 1 to 10, or the method of diagnosis of claim 11.

13. A method of monitoring of a therapy of adenomyosis in a subject, which comprises the method of imaging of any one of claims 1 to 10, or the method of diagnosis of claim 11.

14. The use of99mTc-maraciclatide or a non-radioactive maraciclatide kit in one or more of the following: (i) the method of imaging of any one of claims 1 to 10, (ii) the method of diagnosis of claim 11; (iii) the method of determination of therapy of claim 12; (iv) the method of monitoring of therapy of claim 13; wherein said maraciclatide kit is for the preparation of99mTc-maraciclatide.

15. The use of a gamma camera, gamma detector and / or image processing software in one or more of the following: (i) the method of imaging of any one of claims 1 to 10, (ii) the method of diagnosis of claim 11; (iii) the method of determination of therapy of claim 12; (iv) the method of monitoring of therapy of claim 13.2025.05.09 Specification – P000705WO 38 16.99mTc-maraciclatide for use in a method of diagnosis of adenomyosis, wherein said method of diagnosis comprises the method of imaging of any one of claims 1 to 10.

Images