Biodistribution Studies of a New Antitumor Compound Based on Nanoporous Nanodiamond Composite Labeled with Rhenium-188

This study evaluated a new drug delivery system for local radiotherapy on the base of nanoporous nanodiamond composites (NDC) labeled with β-emitting radionuclide rhenium-188. The biodistribution of labeled compound was assessed after intratumoral (i.t.) and intramuscular (i.m.) injection. 24 mice-bearing solid Ehrlich carcinoma xenografts received i.t. injections of 0.370 ± 0.074 MBq 188Re-nanoporous diamond composites. Another 24 intact mice were injected with the same preparation intramuscularly. The samples of different organs and tissues were collected for gamma count. After i.t. and i.m. administration of 188Re-nanoporous NDC a considerable amount of radioactivity retained at the site of injection. In tumor tissue the total amount of activity decreased from 92.68 % to 9.63 % of injected dose (ID) throughout the study. The removal of injected activity from muscular tissue was faster as compared with tumor tissue, and declined from 81.06 % to 8.40 % ID for up to 72 h. Therefore, after i.m. injection the accumulation of radioactivity in healthy organs and tissues was slightly higher than after i.t. injection. In conclusion, it was demonstrated that 188Renanoporous diamond composites had the potential radiotherapeutic significance. Keywords: composite materials, nanodiamond, rhenium-188, cancer radiotherapy, local radiotherapy

Preliminary Biological Evaluation of Leucine Labeled with Gallium-68—A Potential Agent for Tumor Imaging

Amino acids are important nutrients for proliferating tumor cells, so their transport is generally increased in many malignant tumor cells. Radiolabeled amino acids are of great interest as they can be alternative or complement tracers to the already wellestablished radiopharmaceuticals such as 18F-FDG. The purpose of this study was to synthesize and characterize a novel 68Ga labeled leucine analog, 68Ga-leucine, as a potential imaging agent for tumors which may not be amenable to imaging by 18F-FDG PET. Biodistribution studies of 68Ga-leucine were performed in Wistar rats with transplanted cholangioma RS-1 xenografts after intravenous injection. 68Ga-leucine demonstrated high in vivo stability. Accumulation of 68Ga-leucine at xenograft tumors was about 2-4 higher as compared with 68GaCl3 and reached 0.79% ID/g. Among the soft tissue organs, only kidney had a relatively high uptake. The amount of radioactivity in other organs didn’t exceed 1% ID/g. The results suggest that 68Ga-leucine has the potential to be a new additional diagnostic tool for PET imaging of tumors. Keywords: gallium-68, leucine, radiolabeled amino acids, positron emission tomography, tumor imaging

Preclinical Evaluation of Antitumor Efficacy of a New Radiopharmaceutical Based on Thermoresponsive Carrier and Samarium-153

This work is devoted to studying the in vivo antitumor efficacy of the new injection radiopharmaceutical based on thermoresponsive polymer and β−-emitting radionuclide samarium-153 (153Sm-KARP-CheM). The study of in vivo antitumor efficacy was performed using mice F1 and C57Bl/6 with transplanted subcutaneously sarcoma S37 and melanoma B16, respectively. The animals received single intratumoral bolus injections of 37 MBq (1 mCi), or 18.5 MBq (0.5 mCi) of 153Sm-KARP-CheM, or saline in a volume 0.1 ml. The efficacy of antitumortreatment was evaluated using tumor growth inhibition index (TGI, %) and increase of average life span (ILS, %). The most meaningful therapeutic efficacy after intratumoral injection of 153Sm-KARPCheM was observed in melanoma-bearing mice C57Bl/6. The highest values of TGI for melanoma B16 were 79.5% and 79.6% after treatment with 18.5 MBq or 37 MBq, respectively. An increase of average life span by 17.1% was found in group of melanoma-bearing mice treated with 37 MBq of 153Sm-KARP-CheM only. Tumor growth inhibition of sarcoma S37 was slightly lower as compared with melanoma B16: 62.5% and 59.0% in 37 MBq and 18.5 MBq groups, respectively. 153Sm-KARP-CheM didn’t increase average life span of treated animals. In conclusion, 153Sm-KARP-CheM seems to be effective radiopharmaceutical for local tumor radiotherapy. Keywords: thermoresponsive polymer, samarium-153, radionuclide therapy of cancer, sarcoma S37, melanoma B16, antitumor efficacy

Antitumor Activity of Auger Electron Emitter 111In Delivered by Modular Nanotransporter for Treatment of Bladder Cancer With EGFR Overexpression

Gamma-ray emitting 111In, which is extensively used for imaging, is also a source of short-range Auger electrons (AE). While exhibiting negligible effect outside cells, these AE become highly toxic near DNA within the cell nucleus. Therefore, these radionuclides can be used as a therapeutic anticancer agent if delivered precisely into the nuclei of tumor target cells. Modular nanotransporters (MNTs) designed to provide receptor-targeted delivery of short-range therapeutic cargoes into the nuclei of target cells are perspective candidates for specific intracellular delivery of AE emitters. The objective of this study was to evaluate the in vitro and in vivo efficacy of 111In attached MNTs to kill human bladder cancer cells overexpressing epidermal growth factor receptor (EGFR). The cytotoxicity of 111In delivered by the EGFR-targeted MNT (111In-MNT) was greatly enhanced on EJ-, HT-1376-, and 5637-expressing EGFR bladder cancer cell lines compared with 111In non-targeted control. In vivo microSPECT/CT imaging and antitumor efficacy studies revealed prolonged intratumoral retention of 111In-MNT with t½ = 4.1 ± 0.5 days as well as significant dose-dependent tumor growth delay (up to 90% growth inhibition) after local infusion of 111In-MNT in EJ xenograft-bearing mice

Распределение активности в крови и моче пациентов, получающих системную терапию радиофармпрепаратом с 177Lu и локальную (внутрисуставную) терапию радиофармпрепаратом с 188Re

Pharmacokinetic parameters are important for calculating the absorbed dose; they also provide an indirect measure of the in vivo stability of a radiopharmaceutical. The aim of the study was to determine the excretion rate of the activity of 177Lu-DOTA-PSMA-617 and MCA 5–10 microns, 188Re, from the blood and urine of patients undergoing systemic and local radiotherapy in clinical trials. Materials and methods: the study involved radiometry of blood and urine samples of 12 male patients with metastatic prostate cancer and 20 patients of both sexes with chronic synovitis, selected after radiotherapy with the experimental radiopharmaceuticals 177Lu-DOTA-PSMA-617 and MCA 5–10 microns, 188Re, respectively. The activity of the samples was measured using a dose calibrator and a gamma counter. Results: the activity of 177Lu in the blood of patients was 36.0–89.3%, 10.4–55.7%, 14.6–32.8%, 10.6–35.7%, and 7.3–25.1% at 5 minutes and at 1, 3, 6 and 8 hours after the administration of 177Lu-DOTA-PSMA-617, respectively. The 48-hour urine excretion varied within 34.4–88.8% for 177Lu-DOTA-PSMA-617 and within 0.15–2.91% for MCA 5–10 microns, 188Re. Conclusions: the maximum values of 177Lu-DOTA-PSMA-617 activity in the blood 8 hours after administration (9.6–25.1%) corresponded to the maximum injected activity of the radiopharmaceutical product. The low rate of 188Re urinary excretion after intra-articular administration of MCA 5–10 microns, 188Re, is an indirect indication of the quality of the radiopharmaceutical. The obtained pharmacokinetic parameters show high in vivo stability of the 177Lu and 188Re medicinal products. The results obtained will be used to calculate absorbed doses in patients.Параметры фармакокинетики радиофармпрепарата являются важными характеристиками для расчета поглощенной дозы, а также косвенной характеристикой его стабильности in vivo. Цель работы: определить скорость выведения активности «177Lu-ДОТА-ПСМА» и «МСА 5–10 мкм, 188Re» из крови и мочи пациентов при проведении системной и локальной радиотерапии в рамках клинических исследований. Материалы и методы: для радиометрии использовались образцы крови и мочи 12 мужчин с метастатическим раком простаты и 20 пациентов обоего пола с хроническим синовитом, отобранные после проведения радиотерапии экспериментальными радиофармпрепаратами: «177Lu-ДОТА-ПСМА» и «МСА 5–10 мкм, 188Re». Измерения активности образцов проводились на дозкалибраторе и гамма-счетчике. Результаты: активность 177Lu в крови через 5 мин, 1, 3, 6 и 8 ч после введения «177Lu-ДОТА-ПСМА» составила 36,0–89,3, 10,4–55,7, 14,6–32,8, 10,6–35,7 и 7,3–25,1% соответственно. Выведение с мочой препаратов из организма через 48 ч после радиотерапии для «177Lu-ДОТА-ПСМА» составила 34,4–88,8%, для «МСА 5–10 мкм, 188Re» – 0,15–2,91%. Выводы: максимальные значения активности в крови через 8 ч после инъекции «177Lu-ДОТА-ПСМА» 9,6–25,1% соответствовали максимальной введенной активности препарата. Низкая скорость выведения с мочой 188Re при внутрисуставном введении «МСА 5–10 мкм, 188Re» косвенно указывает на качество радиофармпрепаратов. Полученные фармакокинетические параметры свидетельствуют о высокой стабильности препаратов с 177Lu и 188Re in vivo. Полученные результаты будут использованы при расчете поглощенных доз в организме пациентов

Радиолигандная терапия 177Lu-ДОТА-ПСМА при метастатическом кастрационно-резистентном раке предстательной железы. Фармакокинетика, безопасность, противоопухолевая эффективность

INTRODUCTION: The results of studies of clinical potential of a new domestic radiopharmaceutical 177Lu-DOTA-PSMA in patients with metastatic castration-resistant prostate cancer are presented in this article.OBJECTIVE: The pharmacokinetics, safety and tolerability of radiopharmaceutical were studied. Tolerability of increasing activities — 5.0, 7.5 and 10.0 GBq was investigated.MATERIALS AND METHODS: The study included 12 patients with metastatic castration-resistant prostate cancer, who progressed after previous treatment. The first 4 patients was treated by 5 GBq of 177Lu DOTA-PSMA, the next 4 patients of the second group was treated by 7.5 GBq, and the 4 patients of the third group was treated by 10 GBq. Radiopharmacokinetics was studied by whole-body scintigraphy, SPECT/CT, blood and urine radiometry. The radiation-absorbed dose (RAD) of metastases and organs at risk was studied by clinical dosimetry. Safety assessment also was studied by hematological status. All patients was taken a complete blood count, a biochemical blood test before course of therapy treatable and during the case study.RESULTS: Study data showed high accumulation of 177Lu-DOTA-PSMA the in pathological focus, the distribution in the body conformed to the previous data of PET/CT study. Blood radiometry showed that 177Lu-DOTA-PSMA rapidly excreted from the bloodstream (during the first hours after injection). Urine radiometry showed that, more than half of the injected dose was excreted during 2 days (from 34.4% to 88.8%).DISCUSSION: During the study was solicited increasing of pain syndrome, dry mouth. Most patients had moderate myelosuppression. Changes in hematological parameters had a transistor character, the adverse event resolved without consequences in 5 week. 4th grade of NCI CTCAE hematological toxicity criteria wasn’t identified. Serious adverse events weren’t identified too.CONCLUSIONS: Radiopharmaceutical demonstrated high affinity for tumor tissue and safety in the clinical use. Data, which demonstrating a high potential anti-tumor efficacy of radiopharmaceutical, were obtained. Dosimetric studies showed radiation safety of work with radiopharmaceutical for the personnel.ВВЕДЕНИЕ: В статье представлены результаты исследований клинических возможностей нового отечественного радиофармпрепарата 177Lu-ДОТА-ПСМА у пациентов с метастатическим кастрационно-резистентным раком предстательной железы.ЦЕЛЬ: Изучена фармакокинетика, безопасность и переносимость препарата. Исследована переносимость возрастающих активностей — 5, 7,5 и 10 ГБк.МАТЕРИАЛЫ И МЕТОДЫ: В исследование были включены 12 пациентов с метастатическим кастрационно-резистентным раком предстательной железы, прогрессирующим на фоне предшествующего лечения. Всем пациентам препарат вводили однократно внутривенно. Первые 4 пациента получили по 5 ГБк 177Lu-ДОТА-ПСМА, следующие 4 пациента второй группы, получили по 7,5 ГБк, а 4 пациента третьей группы — по 10 ГБк. С целью изучения фармакокинетики препарата каждому из 12 пациентов после введения 177Lu-ДОТА-ПСМА проводили сцинтиграфию всего тела, ОФЭКТ/КТ. Для изучения динамики выведения препарата из организма выполнялась радиометрия крови и мочи. С целью дозиметрии проводилась оценка величин поглощенных доз внутреннего облучения в метастатических очагах и органах риска. Для изучения безопасности всем пациентам выполнялся общий анализ крови, биохимический анализ крови, до введения и на протяжении 5 недель наблюдения в установленные сроки согласно протоколу клинического исследования.РЕЗУЛЬТАТЫ: По данным сцинтиграфии всего тела и ОФЭКТ/КТ исследуемый препарат продемонстрировал высокое накопление в патологических очагах, его распределение в организме соответствовало данным, полученным при предшествующем ПЭТ/КТ исследовании. Величины поглощенных доз в метастатических очагах сильно различались как у разных пациентов, так и в различных очагах одного и того же пациента. Их значения достигали 30 Гр и более. Радиометрия крови показала, что препарат 177Lu-ДОТА-ПСМА быстро (в течение первых часов после введения) выводится из кровяного русла. Радиометрия мочи показала, что в течение 2 суток с мочой выводится в среднем более половины от введенной активности (от 34,4 до 88,8%).ОБСУЖДЕНИЯ: Нежелательные явления: было отмечено усиление болевого синдрома у 2 пациентов, умеренная сухость во рту у 3 пациентов. У большинства пациентов наблюдалась умеренная миелосупрессия. Изменения гематологических показателей имели транзиторный характер, к пятой неделе в большинстве случаев нежелательные явление разрешились без последствий. Осложнений 4-й степени согласно критериям гематологической токсичности NCI CTCAE отмечено не было. Серьезных нежелательных явлений обнаружено не было.ЗАКЛЮЧЕНИЕ: Получены данные, демонстрирующие высокую потенциальную противоопухолевую эффективность препарата. Дозиметрические исследования показали радиационную безопасность работ с препаратом для персонала. Препарат продемонстрировал высокую тропность к опухолевой ткани и безопасность при клиническом применении

Radioactivity distribution in the blood and urine of patients receiving systemic therapy with a ¹⁷⁷Lu radiopharmaceutical and local (intra-articular) therapy with a ¹⁸⁸Re radiopharmaceutical

Pharmacokinetic parameters are important for calculating the absorbed dose; they also provide an indirect measure of the in vivo stability of a radiopharmaceutical. The aim of the study was to determine the excretion rate of the activity of 177Lu-DOTA-PSMA-617 and MCA 5–10 microns, 188Re, from the blood and urine of patients undergoing systemic and local radiotherapy in clinical trials. Materials and methods: the study involved radiometry of blood and urine samples of 12 male patients with metastatic prostate cancer and 20 patients of both sexes with chronic synovitis, selected after radiotherapy with the experimental radiopharmaceuticals 177Lu-DOTA-PSMA-617 and MCA 5–10 microns, 188Re, respectively. The activity of the samples was measured using a dose calibrator and a gamma counter. Results: the activity of 177Lu in the blood of patients was 36.0–89.3%, 10.4–55.7%, 14.6–32.8%, 10.6–35.7%, and 7.3–25.1% at 5 minutes and at 1, 3, 6 and 8 hours after the administration of 177Lu-DOTA-PSMA-617, respectively. The 48-hour urine excretion varied within 34.4–88.8% for 177Lu-DOTA-PSMA-617 and within 0.15–2.91% for MCA 5–10 microns, 188Re. Conclusions: the maximum values of 177Lu-DOTA-PSMA-617 activity in the blood 8 hours after administration (9.6–25.1%) corresponded to the maximum injected activity of the radiopharmaceutical product. The low rate of 188Re urinary excretion after intra-articular administration of MCA 5–10 microns, 188Re, is an indirect indication of the quality of the radiopharmaceutical. The obtained pharmacokinetic parameters show high in vivo stability of the 177Lu and 188Re medicinal products. The results obtained will be used to calculate absorbed doses in patients