Tumor neuroendocrino y terapia con lutecio / Neuroendocrine tumor and lutetium therapy / Tumor neuroendócrino e terapia com lutecio

Resumen: Introducción: los tumores neuroendocrinos gastroenteropancreáticos (GEP-NET) son un grupo diversos de tumores de origen en las células neuroendocrinas, la mayoría son esporádicos. Se clasifican según origen, secreción hormonal y diferenciación celular. El tratamiento con péptidos radiomarcados o Peptide Receptor Radionuclide Therapy (PRRT) con lutecio 177-DOTATATE fue aprobado por la FDA en el 2018, ya que ha mostrado buenos resultados en tumores avanzados comparado con otras terapias. Presentamos un caso de una paciente con tumor neuroendocrino pancreático con secundarismo hepático tratada con este fármaco. Caso clínico: paciente de sexo femenino de 65 años, portadora de un tumor neuroendocrino pancreático con secundarismo hepático diagnosticado por biopsia y con expresión de receptores de somatostatina. Por su extensión lesional se indica tratamiento médico con análogos de somatostatina que son mal tolerados, tras lo cual se plantea quimioterapia (QT), con progresión tumoral bajo tratamiento. Dada la mala evolución se inicia tratamiento con PRRT como es lutecio 177-DOTATATE. Se observó que los ciclos con lutecio 177-DOTATATE lograron una disminución mínima del tamaño y de la captación tumoral a nivel pancreático, las metástasis hepáticas no presentaron cambios, y la paciente persistió clínicamente estable. Conclusión: El tratamiento con lutecio 177-DOTATATE en una paciente con un tumor neuroendocrino no funcionante con metástasis, irresecable quirúrgicamente, produjo una respuesta aceptable para un tratamiento paliativo, ya que no se produjo progresión tumoral. La paciente persiste clínicamente estable, asintomática, con un seguimiento a 8 años. El tratamiento con lutecio 177-DOTATATE es una opción efectiva con efectos adversos limitados en tumores GEP-NET irresecables o con metástasis.

Summary: Introduction: gastroenteropancreatic neuroendocrine neoplasms (GEP-NET) are a group of several tumors originated in neuroendocrine cells, most of which are sporadic. These tumors are classified according to hormone secretion and cell differentiation. Treatment with radiomarked peptides or Peptide Receptor Radio- nuclide Therapy (PRRT) with lutetium 177-DOTATATE was approved by the FDA in 2018, since it has evidenced good results in advanced tumors compared to other therapies. The study presents the case of a patient with a pancreatic neuroendocrine tumor with secondary hepa tic disease who was treated with this drug. Clinical case: 65-year-old female patient carrier of a pancreatic neuroendocrine tumor with secondary hepatic disease who was diagnosed with a biopsy and presented somatostatin receptor (SSTR) expression. Given the extension of the lesion, medical treatment is indicated with somatostatin analogues that are poorly tolerated. Consequently, chemotherapy is indicated, with low performance tumor progression. Given the poor outcome, PRRT treatment as lutetium 177-DOTATATE is initiated. Cycles with lutetium 177-DOTATATE were observed to cause a minimum reduction in size and tumor uptake in the liver. Liver metastases evidenced no change and the patient remained clinically stable. Conclusion: lutetium 177-DOTATATE therapy in a patient with a metastatic nonfunctioning neuroendocrine tumor, that could not be surgically resected produced an acceptable response for palliative treatment, since the tumor failed to progress. The patient continues to be clinically stable, asymptomatic, after 8 years of follow-up. Lutetium 177-DOTATATE therapy constitutes an effective option with limited side effects in unresectable GEP-NET tumors, or in the presence of metas tases.

Resumo: Introdução: os tumores neuroendócrinos gastroenteropancreáticos (GEP-NET) são um grupo diverso de tumores de origem em células neuroendócrinas, a maioria das quais esporádicos. São classificados de acordo com a origem, secreção hormonal e diferenciação celular. O tratamento com peptídeos radiomarcados ou terapia com radionuclídeos com receptor de peptídeos (PRRT) com 177 Lutecio-Dotatate foi aprovado pela FDA em 2018, pois mostrou bons resultados em tumores avançados em comparação com outras terapias. Apresentamos o caso de um paciente com tumor neuroendócrino pancreático com secundarismo hepático tratado com esse medicamento. Caso clínico: paciente do sexo feminino, 65 anos, portadora de tumor neuroendócrino pancreático com doença hepática secundária diagnosticada por biópsia e com expressão de receptores de somatostatina. Devido à extensão da lesão, o tratamento clínico é indicado com análogos da somatostatina que são pouco tolerados, após o que se considera a quimioterapia (TC), com progressão do tumor em tratamento. Dada a má evolução, foi iniciado tratamento com PRRT, como o 177 Lutecio-Dotatate. Observou-se que os ciclos com 177 Lutecio-Dotatate obtiveram diminuição mínima no tamanho e captação do tumor em nível pancreático, as metástases hepáticas não apresentaram alterações e o paciente manteve-se clinicamente estável. Conclusão: o tratamento com 177Lutecio-Dotatate em um paciente com tumor neuroendócrino não funcionante com metástases, não ressecável cirurgicamente, produziu uma resposta aceitável para o tratamento paliativo, uma vez que não ocorreu progressão do tumor. O paciente permanece clinicamente estável, assintomático, com seguimento de 8 anos. O tratamento com 177Lu-Dotatate é uma opção eficaz com efeitos adversos limitados em tumores GEP-NET não ressecáveis ou metastáticos.

Safety Profile and Therapeutic Efficacy of One Cycle of Lu177-PSMA in End-Stage Metastatic Castration-Resistant Prostate Cancer Patients with Low Performance Status / 대한핵의학회잡지

PURPOSE: The aim of this study was to evaluate safety and therapeutic efficacy of lutetium 177 prostate-specific membrane antigen (Lu-177-PSMA) in metastatic castration-resistant prostate cancer (mCRPC) patients with low performance status.METHODS: Twenty-two patients already treated with anti-androgens and docetaxel were enrolled for one cycle of Lu-177-PSMA therapy. Haemoglobin, total leukocyte counts, platelets and serum creatinine for toxicity profile while prostate specific antigen (PSA), Eastern Cooperative Oncology Group (ECOG) performance status, visual analogue scale (VAS) and analgesic quantification scale (AQS) for therapeutic efficacy were recorded pre and 8 weeks post therapy. Wilcoxon signed-rank and ANOVA tests were used for statistical analysis.RESULTS: Partial response (PR), stable disease (SD) and progressive disease (PD) for PSAwere seen in 5 (22.7%), 13 (59.1%) and 4 (18.2%) patients respectively treated with mean 6.88 GBq dose of Lu-177-PSMA. 8/22 (36.4%) patients showed ≥ 30% drop in PSA. Grade 3 haemoglobin toxicity was seen in 5/22 (22.7%) patients. No patient developed grade 4 haemoglobin toxicity. No patients had grade 3 or 4 leukocytopenia or thrombocytopenia. Wilcoxon signed-rank test showed statistical significant (P < 0.05) difference in pre and post treatment ECOG, VAS, and AQS scores. The ANOVA test showed statistically significant difference in mean doses of Lu-177-PSMA used in three PSA response groups while difference was non-significant for other variables.CONCLUSION: We concluded that Lu-177-PSMA therapy has adequate pain palliation in end-stage mCRPC patients with low performance status and it has a potential to become effective therapeutic option in properly selected patients.

Current Status and Growth of Nuclear Theranostics in Singapore / 대한핵의학회잡지

The concept of theranostics, where individual patient-level biological information is used to choose the optimal therapy for that individual, has become more popular in the modern era of ‘personalised’ medicine. With the growth of theranostics, nuclear medicine as a specialty is uniquely poised to grow along with the ever-increasing number of concepts combining imaging and therapy. This special report summarises the status and growth of Theranostic Nuclear Medicine in Singapore.We will cover our experience with the use of radioiodine, radioiodinated metaiodobenzylguanidine, peptide receptor radionuclide therapy, prostate specific membrane antigen radioligand therapy, radium-223 and yttrium-90 selective internal radiation therapy.We also include a section on our radiopharmacy laboratory, crucial to our implementation of theranostic principles. Radionuclide theranostics has seen tremendous growth and we hope to be able to grow alongside to continue to serve the patients in Singapore and in the region.

Peptide Receptor Radionuclide Therapy and the Treatment of Gastroentero-pancreatic Neuroendocrine Tumors: Current Findings and Future Perspectives / 대한핵의학회잡지

PURPOSE AND METHODS: Patients with inoperable andmetastasized neuroendocrine tumors (NETs), particularly those with grades 1 and 2, usually receive treatment with somatostatin analogues (SSAs). Peptide receptor radionuclide therapy (PRRT) has gained momentum over the past two decades in patients who progress on SSAs. 177Lu-DOTATATE is currently the most widely used radiopeptide for PRRT. We reviewed the recent evidence on PRRT and the treatment of gastroentero-pancreatic neuroendocrine tumors (GEP-NETs).RESULTS: ¹⁷⁷Lu-DOTATATE can be used as neoadjuvant treatment in patients with inoperable GEP-NETs, who might be candidate for surgery after treatment and as adjuvant therapy after surgical intervention. Combination treatments of PRRT with chemotherapy or targeted agents as well as combinations of radionuclides in patients with NETs have been explored over the last few years. The majority of patients with NETs experience partial response or have disease stabilization, a small percentage has complete response, while some 30% of patients, however, will have disease progression. The safety and efficacy of retreatment with extra cycles of PRRT as salvage therapy have been evaluated in small retrospective series.CONCLUSION: Overall, there is evidence that disease control and quality of life improve significantly after 117Lu PRRT therapy. Clinical trials on this therapy are scarce, and there is a need for further studies to establish proper management guidelines.

Production, quality control, biodistribution assessment and preliminary dose evaluation of [177Lu]-tetra phenyl porphyrin complex as a possible therapeutic agent / Produção, controle de qualidade, avaliação de biodistribuição e avaliação da dose preliminar de [177Lu] -tetra complexo fenil porfirina como um possível agente terapêutico

Due to interesting therapeutic properties of ¹⁷⁷Lu and tumor avidity of tetraphenyl porphyrins (TPPs), ¹⁷⁷Lu-tetraphenyl porphyrin was developed as a possible therapeutic compound. ¹⁷⁷Lu of 2.6-3 GBq/mg specific activity was obtained by irradiation of natural Lu₂O₃sample with thermal neutron flux of 4 × 10¹³ n.cm^-2.s^-1. Tetraphenyl porphyrin was synthetized and labeled with ¹⁷⁷Lu. Radiochemical purity of the complex was studied using Instant thin layer chromatography (ITLC) method. Stability of the complex was checked in final formulation and human serum for 48 h. The biodistribution of the labeled compound in vital organs of wild-type rats was studied up to 7 d. The absorbed dose of each human organ was calculated by medical internal radiation dose (MIRD) method. A detailed comparative pharmacokinetic study was performed for ¹⁷⁷Lu cation and [¹⁷⁷Lu]-TPP. The complex was prepared with a radiochemical purity: >97±1% and specific activity: 970-1000 MBq/mmol. Biodistribution data and dosimetric results showed that all tissues receive approximately an insignificant absorbed dose due to rapid excretion of the complex through the urinary tract. [¹⁷⁷Lu]-TPP can be an interesting tumor targeting agent due to low liver uptake and very low absorbed dose of approximately 0.036 to the total body of human...

Devido às propriedades interessantes do ¹⁷⁷Lu e da avidez tumoral das tetrafenil porfirinas (TPP), desenvolveu-se a ¹⁷⁷Lu-tetrafenil porfirina como composto terapêutico potencial. ¹⁷⁷Lu de atividade específica de 2,6-3 GBq/mg foi obtido por irradiação de amostra de Lu₂O₃ com fluxo térmico de nêutrons de 4 × 10¹³ n.cm^-2.s^-1. Sintetizou-se a tetrafenil porfirina e marcou-se com ¹⁷⁷Lu. A pureza radioquímica do complexo foi estudada usando método de Cromatografia Instantânea de Camada Delgada ( ITLC). A estabilidade do complexo foi checada na formulação final e no ser humano por 48 h. A biodistribuição do composto marcado em órgãos vitais de ratos do tipo selvagem foi estudada por mais de 7 dias. A dose absorvida para cada órgão humano foi calculada pelo método da Dose Médica de Radiação Interna (MIRD). Estudo farmacocinético comparativo detalhado foi efetuado para o cátion ¹⁷⁷Lu e para o [¹⁷⁷Lu]-TPP. O complexo foi preparado com pureza radioquímica >97±1% e atividade específica de 970-1000 MBq/mmol. Os dados de biodistribuição e os resultados dosimétricos mostraram que todos os tecidos receberam uma dose absorvida aproximadamente insignificante devido à rápida excreção do complexo pelo trato urinário. O [¹⁷⁷Lu]-TPP pode ser um agente interessante de direcionamento do tumor devido à baixa captação pelo fígado e pela dose bem baixa absorvida, de, aproximadamente, 0,036 do corpo humano total...

Estudio biocinético y dosimétrico de un kit de producción local de 177Lu-EDTMP para su uso como agente paliativo del dolor / Biokinetic and dosimetric study of 177Lu-EDTMP in the palliative treatment of skeletal metastasis

Los radiofármacos con afinidad por el tejido óseo como el ácido etilen-diamino-tetrametilen-fosfónico (EDTMP) marcado con radioisótopos emisores beta- han demostrado su eficacia en el tratamiento paliativo de las metástasis óseas. Se realizó un estudio biocinético y dosimétrico del 177Lu-EDTMP en ratones NIH. Los resultados obtenidos fueron extrapolados a humanos. Se estimó la dosis absorbida en órganos para dos modelos: un hombre adulto y una mujer adulta. El 177Lu-EDTMP posee una selectiva captación en hueso, una rápida eliminación en sangre e insignificante captación en tejidos no óseos. La dosis en hueso estimada para el hombre se encuentra entre 14,7-15,3 cGy/mCi y entre 19,6-20,4 cGy/mCi para la mujer. La toxicidad en médula ósea representa el factor limitante de este tipo de terapia, y para evitar superar la dosis máxima que ésta puede tolerar (200 cGy), se encontró que la actividad máxima segura de 177Lu-EDTMP que puede ser inyectada al hombre (73,9Kg), corresponde a un valor de 1,01 mCi/kg y a un valor de 1,25 mCi/Kg para la mujer (56,9Kg).

Bone-seeking radiopharmaceuticals like the ethylenediaminetetramethylene phosphonic acid (EDTMP) labeled with beta--emitting radioisotopes have demonstrated their efficacy in the palliative treatment of skeletal metastasis. A biokinetic and dosimetric study of 177Lu-EDTMP in NIH mice was performed. The results obtained were extrapolated to human. We estimate the absorbed doses in organs for two models: an adult male and an adult female. 177Lu-EDTMP has a selective uptake in bone, a rapid elimination from blood and negligible uptake in non-skeletal tissues. The estimated dose in bone is between 14.7-15.3 cGy/mCi for men and between 19.6-20.4 cGy/mCi for women. Bone marrow toxicity represents the limiting factor in this kind of therapy, and to avoid exceed the maximum dose it can tolerate (200 cGy), it was found that the maximum safe activity of 177Lu-EDTMP to be injected to male (73.9 kg), corresponds to a value of 1.01 mCi/kg and a value of 1.25 mCi/kg for female (56.9 kg).

Ensayos in-vitro e in-vivo del péptido marcado 177Lu-DOTA-Sustancia P y evaluación de los cálculos dosimétricos en la etapa preclínica / Tests in-vitro and in vivo of 177Lu-DOTA-SP labeled peptide and evaluation of the dosimetric calculations in the preclinical stage

Introducción: El péptido Sustancia P (SP) es el ligando principal de los receptores de neurokininas tipo 1, los cuales se encuentran sobreexpresados en los gliomas malignos. Método: Se obtuvo 177Lu-DOTA-SP con elevada pureza radioquímica. Se realizaron biodistribuciones en ratones normales a diferentes tiempos. Se calcularon las dosis absorbidas para los diferentes órganos del ratón (cGy/uCi). Utilizando los métodos de escalación por tiempo (A) y extrapolación directa (B), se obtuvieron las dosis en los diferentes órganos humanos. Se calcularon las máximas dosis tolerables en función de los órganos críticos (mCi/kg). Resultados: La máxima actividad tolerable que puede ser inyectada sin producir toxicidad en riñones es 11,2 mCi/kg (hombre adulto) y 11,4 mCi/kg (mujer adulta) según el método A y de 47,2 mCi/kg y 56,2 mCi/kg, respectivamente según el método B. Conclusiones: Hasta el momento se pudo obtener 177Lu-DOTA-SP con Ae= 0,05mCi/ ug de péptido. La misma puede aumentarse utilizando el 177LuCl3 de mayor actividad específica.

Introduction: Substance P (SP) is the main ligand of neurokin type 1 receptors, which are consistently overexpressed in malignant gliomas. Method: 177Lu-DOTA-SP was obtained with high radiochemical purity. Biodistribution in normal mice at different times, were done. Absorbed doses were calculated for different mice organs (cGy/uCi). Absorbed doses in human organs were calculated using two different methods, time scaling (A) and data extrapolation (B). Maximum tolerated doses were calculated according to critical organs (mCi/kg). Results: Maximum tolerated dose that can be injected without kidney toxicity is 11,2 mCi/kg (adult man) and 11,4 mCi/kg (adult woman) according to method A and 47,2 mCi/kg, 56,2 mCi/kg, respectively according to method B. Conclusion: So far, 177Lu-DOTA-SP was achieved with a specific activity (S.a) of 0,05 mCi/ ug of peptide. This S.a can be increased using 177LuCl3 of higher specific activity.

Tratamiento de tumores neuroendocrinos (TNE) con péptidos análogos de la somatostatina marcados con radionucleidos / Treatment of neuroendocrine tumors (NET) with radiolabelled somatostatin analogues

Propósito. Los TNE avanzados tienen escasa respuesta a radioterapia o quimioterapia, el tratamiento sistémico con análogos de la SST radiactivos es una herramienta promisoria en su tratamiento. Presentamos nuestra experiencia, pionera en Latinoamérica, utilizando análogos de SST marcados con 90Y ó 177Lu. Material. Evaluamos 40 pacientes (50.3 años, rango 12-74) con TNE confirmados histológicamente y sobre-expresión de receptores de SST demostrada mediante imágenes. SPECT (111In-DOTATOC) ó PET/CT (68Ga-DOTATATE). Se evaluó respuesta clínica, laboratorio, imágenes con 111In-DOTATATE, post-terapia con 90Y ó 177Lu, 68Ga-DOTATATE PET/CT o TAC. Resultados. Observamos progresión de enfermedad en 10 (25.0 por ciento), remisión parcial en 25 (62.5 por ciento), enfermedad estable en 3 (7.5 por ciento) y remisión completa en 2 (5.0 por ciento). Hubo escasa toxicidad sin deterioro renal significativo. Observamos reducción tumoral y mejoría de calidad de vida en la mayoría de los pacientes. Conclusión. La terapia con radiopéptidos es un procedimento seguro y efectivo en el tratamiento de TNE avanzados.

Purpose. Advanced NETs have little response to radiotherapy or chemotherapy, systemic treatment with radioactive SST analogous is a promissory tool in its treatment. We present our pioneering experience in Latin America using analogous of SST labeled either with 90Y or 177Lu. Materials. We evaluated 40 patients (50.3 years, range 12-74) with histological proved NET and SST receptors over-expression demonstrated by SPECT or PET/CT images with 111In-DOTATOC or 68Ga-DOTATATE. We evaluated clinical response, laboratory test, images with 111In-DOTATATE, 90Y, 177Lu, and 68Ga-DOTATATE PET/CT or CT. Results. We observed progression of disease in 10 (7,5 percent), partial remission in 25 (62,5 percent), stable disease in 3 (7,5 percent) and complete remission in 2 (5,0 percent). There was little toxicity without significant renal deterioration. We observed tumor mass reduction and improvement of quality of life in most of the patients. Conclusion. The therapy with radiopeptides is a safe and effective procedure in the treatment of advanced NET.

Production of 177Lu and formulation of Ethylene diamine tetramethylene phosphonate [EDTMP] kits as a bone-seeking radiopharmaceutical

Owing to its favourable decay characteristics 177Lu [T1/2= 6.71 d, Ebeta[max]= 497 keV] is an attractive radionuclide for various therapeutic applications. Ethylene diamine tatramethylene phosphonate [EDTMP] is one of the most widely used ligands which form stable complexes with various radionuclides and all the complexes. Enriched 176Lu2O3 was dissolved in 0.1 N HCl and evaporated several times and 176LuCl3 target was irradiated at 2.6x1013 n.Cm- 2.S-1 thermal neutron flux for 14 days.177LuCl3 was dissolved in 1N HCl. EDTMP was dissolved in double distilled water at pH=7.5-8.5 and freeze-dried kits was radiolabeled with 177LuCl3. Distribution studies were done in healthy mice. The yield of 177Lu was [220 TBq/g; 6000 Ci/g], the radionuclidic purity was 99%.The radiolabeling yield of EDTMP kits at 37°C after 30 min and 4 hours was 98 +/- 0.5% and after 72 hours was 90 +/- 2.1%, the in vitro stability in human serum at 37°C up to 72 hours post radiolabeling was 85 +/- 1.8%.The biodistribution studies of 177Lu-EDTMP and 177LuCl3 in normal mice showed skeleton uptake and low soft-tissue concentration. In this study, we produce 220 TBq/g [6000 Ci/g] of 177Lu by neutron activation of 176Lu in the Tehran Research Reactor. Our results showed 177Lu-EDTMP as a bone-seeking radiopharmaceutical. Due to its suitable nuclear characteristics 177Lu appears to be worthwhile for palliative therapy of bone metastasis

Labeling of DOTA-Tyr3-octreotate with 177Lu - stability and biodistribution study

The labeling with 177Lu and quality control procedures to produced DOTA (1,4,7,10-N,N´,N´´,N´´´, tetraazaciclododecane tetraacetic acid) coupled octreotate labeled peptide was evaluated. The labeling was performed using 30µg of DOTA-Tyr3-octreotate and 500 and 1110 MBq of 177Lu, buffered with sodium acetate/acetic acid 0.4M pH 4.5 for 20 minutes at 100ºC. The radiochemical purity was determined by ITLC na HPLC. Biological distribution studies were performed on Nude mices with tumours (AR42J rat pancreatic tumour cells) by invasive method. The stability of the 177Lu-DOTA-Tyr3-octreotate was followed by 7 days, and in both labeling procedures, the radiochemical purity were superior than 98 percent. Biodistribution studies showed fast blood clearance and the kidneys were the critical organs. The uptake in tumour were significant after 24 hours and the labeled peptide showed high in vivo stability.

Development of a Small Animal Positron Emission Tomography Using Dual-Layer Phoswich Detector and Position Sensitive Photomultiplier Tube: Preliminary Results / 대한핵의학회잡지

PURPOSE: The purpose of this study was to develop a small animal PET using dual layer phoswich detector to minimize parallax error that degrades spatial resolution at the outer part of field-of-view (FOV). MATERIALS AND METHODS: A simulation tool GATE (Geant4 Application for Tomographic Emission) was used to derive optimal parameters of small PET, and PET was developed employing the parameters. Lutetium Oxyorthosilicate (LSO) and Lutetium-Yttrium Aluminate-Perovskite (LuYAP) was used to construct dual layer phoswitch crystal. 8 X 8 arrays of LSO and LuYAP pixels, 2 mm X 2 mm X 8 mm in size, were coupled to a 64-channel position sensitive photomultiplier tube. The system consisted of 16 detector modules arranged to one ring configuration (ring inner diameter 10 cm, FOV of 8 cm). The data from phoswich detector modules were fed into an ADC board in the data acquisition and preprocessing PC via sockets, decoder block, FPGA board, and bus board. These were linked to the master PC that stored the events data on hard disk. RESULTS: In a preliminary test of the system, reconstructed images were obtained by using a pair of detectors and sensitivity and spatial resolution were measured. Spatial resolution was 2.3 mm FWHM and sensitivity was 10.9 cps/micro Ci at the center of FOV. CONCLUSION: The radioactivity distribution patterns were accurately represented in sinograms and images obtained by PET with a pair of detectors. These preliminary results indicate that it is promising to develop a high performance small animal PET.