68Ga-Labeled bismacrocyclic methylene phosphonate as potential bone seeking PET radiopharmaceutical.

Phosphonates-based agents are well-known bone-seeking radiopharmaceuticals with application in detection and therapy. With higher sensitivity and resolution offered by Positron Emission Tomography (PET), tracers based on this technique are gaining huge attention. 68Ga-based generator and radiotracers render independence from the on-site cyclotron. We report the development of 68Ga-labeled DOTA-based bismacrocyclic phosphonate derivative, for bone PET imaging. The synthesis and characterization of 68Ga- DO3P-AME-DO3P was carried out in > 95% purity. The radiotracer displayed high stability and low binding affinity (<3%) to blood serum. High in vitro binding affinity were observed for synthetic hydroxyapatite, SAOS-2, osteoclast and osteoblast cells. In vivo pharmacokinetics revealed fast washout with biphasic release pattern. The deposition of radiotracer in osseous tissues was high (Bone/Muscle ratio:18), as studied from the biodistribution studies. In vivo PET/CT and biodistribution analyses revealed the ability of 68Ga-DO3P-AME-DO3P to target and accumulate in bone, thus displaying its potential as a PET bone imaging agent.

Brigatinib Versus Crizotinib in Advanced ALK Inhibitor-Naive ALK-Positive Non-Small Cell Lung Cancer: Second Interim Analysis of the Phase III ALTA-1L Trial.

PURPOSE: Brigatinib, a next-generation anaplastic lymphoma kinase (ALK) inhibitor, demonstrated superior progression-free survival (PFS) and improved health-related quality of life (QoL) versus crizotinib in advanced ALK inhibitor-naive ALK-positive non-small cell lung cancer (NSCLC) at first interim analysis (99 events; median brigatinib follow-up, 11.0 months) in the open-label, phase III ALTA-1L trial (ClinicalTrials.gov identifier: NCT02737501). We report results of the second prespecified interim analysis (150 events). METHODS: Patients with ALK inhibitor-naive advanced ALK-positive NSCLC were randomly assigned 1:1 to brigatinib 180 mg once daily (7-day lead-in at 90 mg once daily) or crizotinib 250 mg twice daily. The primary end point was PFS as assessed by blinded independent review committee (BIRC). Investigator-assessed efficacy, blood samples for pharmacokinetic assessments, and patient-reported outcomes were also collected. RESULTS: Two hundred seventy-five patients were randomly assigned (brigatinib, n = 137; crizotinib, n = 138). With median follow-up of 24.9 months for brigatinib (150 PFS events), brigatinib showed consistent superiority in BIRC-assessed PFS versus crizotinib (hazard ratio [HR], 0.49 [95% CI, 0.35 to 0.68]; log-rank P < .0001; median, 24.0 v 11.0 months). Investigator-assessed PFS HR was 0.43 (95% CI, 0.31 to 0.61; median, 29.4 v 9.2 months). No new safety concerns emerged. Brigatinib delayed median time to worsening of global health status/QoL scores compared with crizotinib (HR, 0.70 [95% CI, 0.49 to 1.00]; log-rank P = .049). Brigatinib daily area under the plasma concentration-time curve was not a predictor of PFS (HR, 1.005 [95% CI, 0.98 to 1.031]; P = .69). CONCLUSION: Brigatinib represents a once-daily ALK inhibitor with superior efficacy, tolerability, and QoL over crizotinib, making it a promising first-line treatment of ALK-positive NSCLC.

(153)Sm-EDTMP for pain relief of bone metastases from prostate and breast cancer and other malignancies.

BACKGROUND AND AIMS: Approximately 85% of patients with cancer suffer severe metastatic bone pain for which radionuclide therapy has been employed for pain palliation. We undertook this study to evaluate the pain relief effect of (153)Sm-EDTMP in Mexican patients with severe and painful bone metastases from mainly prostate, breast, and renal cancer and other malignancies. METHODS: Patients (277) with intense sustained pain caused by bone metastases were referred to the Nuclear Medicine Department of the Oncology Hospital of the Mexican Social Security Institute. The patients had to have acceptable physical conditions, a previous positive (99m)Tc-MDP scan and blood values within normal range. (153)Sm-EDTMP was prepared at the Instituto Nacional de Investigaciones Nucleares (ININ) and 37 MBq/kg of body weight was injected intravenously. Pain palliation was evaluated with a visual analogue scale (VAS) and a verbal rating scale (VRS) before treatment and 3 and 12 weeks after treatment was started. RESULTS: The age interval of the patients was 24-92 years with a mean age of 64 ± 12 years. Mean values for hemoglobin, leukocyte and platelet counts did not statistically differ at zero time, 3 and 12 weeks after treatment. Pain intensity and relief assessment were statistically different: 9.1 ± 0.61 units initially; 4.2 ± 1.3 units 3 weeks later (54%) and after 12 weeks the pain diminished to 2.4 ± 1.4 units (74%) in the pain relief score scales. CONCLUSIONS: (153)Sm-EDTMP was readily available, safe and well tolerated. We conclude that (153)Sm-EDTMP was an adequate palliative agent and was the best option for our Mexican patients to relieve their severe metastatic bone pain.

Study of the correlation between blood cholinesterases activity, urinary dialkyl phosphates, and the frequency of micronucleated polychromatic erythrocytes in rats exposed to disulfoton

Organophosphates (OPs) are widely used as pesticides, and its urinary metabolites as well as the blood cholinesterases (ChEs) activity have been reported as possible biomarkers for the assessment of this pesticide exposure. Moreover, the OPs can induce mutagenesis, and the bone marrow micronucleus test is an efficient way to assess this chromosomal damage. This paper reports a study carried out to verify the correlation among the disulfoton exposure, blood ChEs activity, urinary diethyl thiophosphate (DETP), and diethyl dithiophosphate (DEDTP), as well as micronucleated polychromatic erythrocytes (MNPCEs) frequency. Four groups of rats (n=12) were exposed to disulfoton at 0, 2.8, 4.7, and 6.6 mg kg-1 body weight. The blood ChEs activity, urinary DETP and DEDTP concentrations, and MNPCEs frequency were determined. It was observed that the plasmatic and erythrocytary ChEs activity decreased from 2.9% to 0.5% and from 35.9 to 3.3%, respectively, when the disulfoton dose was increased from 0 to 6.6 mg kg-1 (correlation of 0.99). Urinary DETP and DEDTP concentrations, as well as the MNPCEs frequency, increased from 0 to 6.58 µg mL-1, from 0 to 0.04 µg mL-1, and from 0 to 1.4%, respectively, when the disulfoton dose was increased from 0 to 6.58 mg kg-1 body weight.

Os organofosforados (OPs) são amplamente usados como praguicidas e a atividade da colinesterase sanguínea bem como os metabólitos urinários desses praguicidas têm sido reportados como biomarcadores eficazes para avaliar casos de exposição. Além disso, os OPs podem induzir mutagênese e o teste de micronúcleo de medula óssea é uma boa alternativa para avaliar os danos cromossômicos. Esse artigo reporta um estudo sobre a correlação entre a exposição a dissulfoton, a atividade da colinesterase sanguínea, a excreção urinária de dietil tiofosfato e dietil ditiofosfato e a frequência de micronúcleos em eritrócitos policromáticos. Quatro grupos de ratos (n=12) foram expostos a dissulfotom nas doses de 0, 2,8, 4,7, e 6,6 mg kg-1 de peso corpóreo. A atividade da colinesterase sanguínea as concentrações urinárias de dietil tiofosfato e dietil ditiofosfato e a frequência de micronúcleos foram determinadas. Os resultados demonstraram que as atividades da colinesterase plasmática e eritrocitária diminuíram de 2,9 para 0,5% e de 35,9 para 3,3% , respectivamente, quando a dose de dissulfoton foi aumentada de 0 para 6,6 mg kg-1 (correlação de 0,99). As concentrações urinárias de dietil tiofosfato e dietil ditiofosfato bem como a frequência de micronúcleos aumentaram de 0 a 6,56 µg mL-1, 0 a 0.04 µg mL-1 e de 0 a 1.4%, respectivamente, quando a dose de dissulfotom foi aumentada de 0 a 6,58 mg kg-1.

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).

Biodistribution of samarium-153-EDTMP in rats treated with docetaxel / Biodistribuição de EDTMP-153-samário em ratos tratados com docetaxel

PURPOSE: Many patients with metastatic bone disease have to use radiopharmaceuticals associated with chemotherapy to relieve bone pain. The aim of this study was to assess the influence of docetaxel on the biodistribution of samarium-153-EDTMP in bones and other organs of rats. METHODS: Wistar male rats were randomly allocated into 2 groups of 6 rats each. The DS (docetaxel/samarium) group received docetaxel (15 mg/kg) intraperitoneally in two cycles 11 days apart. The S (samarium/control) group rats were not treated with docetaxel. Nine days after chemotherapy, all the rats were injected with 0.1ml of samarium-153-EDTMP via orbital plexus (25µCi). After 2 hours, the animals were killed and samples of the brain, thyroid, lung, heart, stomach, colon, liver, kidney and both femurs were removed. The percentage radioactivity of each sample ( percent ATI/g) was determined in an automatic gamma-counter (Wizard-1470, Perkin-Elmer, Finland). RESULTS: On the 9th day after the administration of the 2nd chemotherapy cycle, the rats had a significant weight loss (314.50±22.09g) compared (p<0.5) to pre-treatment weight (353.66± 22.8). The percent ATI/g in the samples of rats treated with samarium-153-EDTMP had a significant reduction in the right femur, left femur, kidney, liver and lungs of animals treated with docetaxel, compared to the control rats. CONCLUSION: The combination of docetaxel and samarium-153-EDTMP was associated with a lower response rate in the biodistribution of the radiopharmaceutical to targeted tissues. Further investigation into the impact of docetaxel on biodistribution of samarium-153-EDTMP would complement the findings of this study.

OBJETIVO: Muitos pacientes com metástases ósseas são tratados com radiofármacos associados com quimioterapia para alívio da dor óssea. O objetivo do trabalho foi estudar a influência do docetaxel na biodistribuição do EDTMP-153-samário nos ossos e outros órgãos de ratos. MÉTODOS: Ratos Wistar foram aleatoriamente alocados em 2 grupos de 6 animais cada. O grupo DS (docetaxel/samário) recebeu docetaxel (15 mg/kg) intraperitoneal em dois ciclos com 11 dias de intervalo. Os ratos do grupo S (samário/controle) não foram tratados com docetaxel. Nove dias após a quimioterapia, todos os animais receberam 0,1ml de EDTMP-153-samário via plexo orbital (25µCi). Após 2 horas, os animais foram mortos e feitas biópsias de cérebro, tireóide, pulmão, coração, estômago, cólon, fígado, rim e fêmures. O percentual de radioatividade por grama ( por centoATI/g) de tecido de cada biópsia foi determinado em contador gama automático (Wizard-1470, Perkin-Elmer, Finland). RESULTADOS: No 9º após 2º ciclo de docetaxel os ratos tiveram perda de peso significante, passando de 353,66± 22,8g (controle/pré-tratamento) para 314,50±22,09g (p<0,5). Os por cento ATI/g nos órgãos dos ratos tratados com EDTMP-153-samário e docataxel tiveram redução significante nos fêmures direito e esquerdo, rim, fígado e pulmão, quando comparados com os não tratados com docetaxel. CONCLUSÃO: A combinação de docetaxel com EDTMP-153-samário foi associada com resposta mais baixa na biodistribuição do radiofármaco em órgãos alvo. Futuras investigações sobre o impacto do docetaxel na biodistribuição do EDTMP-153-samário poderão complementar os achados teste estudo.

Biodistribution of samarium-153-EDTMP in rats treated with docetaxel.

PURPOSE: Many patients with metastatic bone disease have to use radiopharmaceuticals associated with chemotherapy to relieve bone pain. The aim of this study was to assess the influence of docetaxel on the biodistribution of samarium-153-EDTMP in bones and other organs of rats. METHODS: Wistar male rats were randomly allocated into 2 groups of 6 rats each. The DS (docetaxel/samarium) group received docetaxel (15 mg/kg) intraperitoneally in two cycles 11 days apart. The S (samarium/control) group rats were not treated with docetaxel. Nine days after chemotherapy, all the rats were injected with 0.1 ml of samarium-153-EDTMP via orbital plexus (25 microCi). After 2 hours, the animals were killed and samples of the brain, thyroid, lung, heart, stomach, colon, liver, kidney and both femurs were removed. The percentage radioactivity of each sample (% ATI/g) was determined in an automatic gamma-counter (Wizard-1470, Perkin-Elmer, Finland). RESULTS: On the 9th day after the administration of the 2nd chemotherapy cycle, the rats had a significant weight loss (314.50+/-22.09g) compared (p<0.5) to pre-treatment weight (353.66+/- 22.8). The % ATI/g in the samples of rats treated with samarium-153-EDTMP had a significant reduction in the right femur, left femur, kidney, liver and lungs of animals treated with docetaxel, compared to the control rats. CONCLUSION: The combination of docetaxel and samarium-153-EDTMP was associated with a lower response rate in the biodistribution of the radiopharmaceutical to targeted tissues. Further investigation into the impact of docetaxel on biodistribution of samarium-153-EDTMP would complement the findings of this study.

Preparation of (166)Dy/(166)Ho-EDTMP: a potential in vivo generator system for bone marrow ablation.

BACKGROUND AND AIM: Bone-seeking radiopharmaceuticals have been proposed for delivering ablative radiation doses to marrow in multiple myeloma and other haematological malignancies. The aim of this research was to examine the feasibility of labelling ethylenediaminetetramethylenephosphonate (EDTMP) with Dy/Ho as an in vivo generator system and to evaluate whether the in vitro and in vivo stability of Dy-EDTMP and Ho-EDTMP complexes is maintained when the daughter Ho is formed. METHODS: Dy was obtained by neutron irradiation of enriched Dy2O3 in a TRIGA Mark III reactor. Labelling was carried out in an aqueous phosphate medium at pH 8.0 by addition of DyCl3 to EDTMP at a molar ratio 1:1.75. Dy/Ho labelled EDTMP was obtained with a 99.3+/-0.6% radiochemical purity determined by thin-layer chromatography and high-performance liquid chromatography. RESULTS: In vitro studies demonstrated that Dy/Ho-EDTMP is unstable after dilution in saline and stable in human serum and no translocation of the daughter nucleus occurring subsequent to beta decay of Dy which could produce release of Ho. Biodistribution in mice shows a fast blood clearance after administration of Dy/Ho-EDTMP with a skeletal uptake of 22.32+/-1.86% ID/g at 2 h and 20.12+/-1.94% ID/g after 10 d, a rapid renal elimination and no accumulation in other organs. Theoretical bone marrow absorbed dose calculations indicate that the Dy/Ho-EDTMP in vivo generator system would produce 7.80 times more radiation dose to marrow than that produced by Sm-EDTMP and 3.47 times more than Ho-DOTMP per unit of initial activity retained in the skeleton. CONCLUSION: The prepared radiolabelled EDTMP has adequate properties as a stable in vivo generator system for bone marrow ablation.

Cell signalling-mediating insulin increase of mRNA expression for cationic amino acid transporters-1 and -2 and membrane hyperpolarization in human umbilical vein endothelial cells.

Insulin induces vasodilatation in human subjects and increases L-arginine transport and NO synthesis in human umbilical vein endothelial cells (HUVEC). Cell signalling events associated with insulin effects on activity and mRNA expression of the human cationic amino acid transporters 1 (hCAT-1) and 2B (hCAT-2B) are unknown. L-arginine transport and eNOS activity were determined in HUVEC exposed to insulin. mRNA levels for hCAT-1, hCAT-2B and eNOS were quantitated by real time RT-PCR and endothelial NO synthase (eNOS) protein was identified by Western blot analysis. Intracellular Ca2+, L-arginine and L-citrulline levels, L-[3H]citrulline formation from L-[(3)H]arginine, cGMP formation, nitrite level, ATP release and membrane potential were determined. Insulin increased L-arginine transport and the mRNA levels for hCAT-1 and hCAT-2B and eNOS expression and activity. Insulin also induced membrane hyperpolarization and increased intracellular Ca2+, L-[3H]citrulline, cGMP and nitrite formation. Insulin-mediated stimulation of the L-arginine/NO pathway is thus associated with increased hCAT-1 and hCAT-2B mRNA, and eNOS expression, via mechanisms involving membrane hyperpolarization, mitogen-activated protein kinases p42 and p44, phosphatidylinositol 3-kinase, NO and protein kinase C. We have characterized a cell signalling pathway by which hyperinsulinaemia could lead to vasodilatation in human subjects, and which could have implications in patients in whom plasma insulin levels are altered, such as in diabetes mellitus.

Rapid stimulation of L-arginine transport by D-glucose involves p42/44(mapk) and nitric oxide in human umbilical vein endothelium.

D-glucose infusion and gestational diabetes induce vasodilatation in humans and increase L-arginine transport and nitric oxide (NO) synthesis in human umbilical vein endothelial cells. High D-glucose (25 mmol/L, 2 minutes) induced membrane hyperpolarization and an increase of L-arginine transport (V(max) 6.1+/-0.7 versus 4.4+/-0.1 pmol/ microg protein per minute) with no change in transport affinity (K(m) 105+/-9 versus 111+/-16 micromol/L). L-[3H]citrulline formation and intracellular cGMP, but not intracellular Ca2+, were increased by high D-glucose. The effects of D-glucose were mimicked by levcromakalim (ATP-sensitive K+ channel blocker), paralleled by p42/p44(mapk) and Ser(1177)-endothelial NO synthase phosphorylation, inhibited by N(G)-nitro-L-arginine methyl ester (L-NAME; NO synthesis inhibitor), glibenclamide (ATP-sensitive K+ channel blocker), KT-5823 (protein kinase G inhibitor), PD-98059 (mitogen-activated protein kinase kinase 1/2 inhibitor), and wortmannin (phosphatidylinositol 3-kinase inhibitor), but they were unaffected by calphostin C (protein kinase C inhibitor). Elevated D-glucose did not alter superoxide dismutase activity. Our findings demonstrate that the human fetal endothelial L-arginine/NO signaling pathway is rapidly activated by elevated D-glucose via NO and p42/44(mapk). This could be determinant in pathologies in which rapid fluctuations of plasma D-glucose may occur and may underlie the reported vasodilatation in early stages of diabetes mellitus.

Usefulness of 99Tcm-tetrofosmin scintimammography in palpable breast tumours.

The aim of this exploratory study was to assess the potential of discriminating malignant from non-malignant lesions using 99Tcm-tetrofosmin scintimammography in the detection of palpable breast tumours. Nine patients with palpable masses were studied; seven had malignant lesions and two had non-malignant lesions. All diagnoses were established by fine-needle aspiration (FNA) biopsy cytology. Each patient received 925 MBq (25 mCi) 99Tcm-tetrosfosmin intravenously. Planar prone views were acquired in the right lateral, left lateral and anterior positions, and the axillary regions were included in the field of view. Scintimammography showed focally increased tracer uptake in seven patients with a positive FNA result. The two patients with a negative FNA result showed no increased uptake. We suggest that 99Tcm-tetrosfosmin shows promise as a radiopharmaceutical in the detection and discrimination of the nature of palpable breast tumours. Larger studies are required to confirm these findings.