Dataset Information

First experience of 18F-alfatide in lung cancer patients using a new lyophilized kit for rapid radiofluorination.

ABSTRACT: UNLABELLED:(18)F-FPPRGD2, which was approved for clinical study recently, has favorable properties for integrin targeting and showed potential for antiangiogenic therapy and early response monitoring. However, the time-consuming multiple-step synthesis may limit its widespread applications in the clinic. In this study, we developed a simple lyophilized kit for labeling PRGD2 peptide ((18)F-AlF-NOTA-PRGD2, denoted as (18)F-alfatide) using a fluoride-aluminum complex that significantly simplified the labeling procedure. METHODS:Nine patients with a primary diagnosis of lung cancer were examined by both static and dynamic PET imaging with (18)F-alfatide, and 1 tuberculosis patient was investigated using both (18)F-alfatide and (18)F-FDG imaging. Standardized uptake values were measured in tumors and other main organs at 30 min and 1 h after injection. Kinetic parameters were calculated by Logan graphical analysis. Immunohistochemistry and staining intensity quantification were performed to confirm the expression of integrin ?(v)?(3). RESULTS:Under the optimal conditions, the whole radiosynthesis including purification was accomplished within 20 min with a decay-corrected yield of 42.1% ± 2.0% and radiochemical purity of more than 95%. (18)F-alfatide PET imaging identified all tumors, with mean standardized uptake values of 2.90 ± 0.10. Tumor-to-muscle and tumor-to-blood ratios were 5.87 ± 2.02 and 2.71 ± 0.92, respectively. CONCLUSION:(18)F-alfatide can be produced with excellent radiochemical yield and purity via a simple, 1-step, lyophilized kit. PET scanning with (18)F-alfatide allows specific imaging of ?v?3 expression with good contrast in lung cancer patients. This technique might be used for the assessment of angiogenesis and for planning and response evaluation of cancer therapies that would affect angiogenesis status and integrin expression levels.

SUBMITTER: Wan W

PROVIDER: S-EPMC3683452 | biostudies-literature | 2013 May

REPOSITORIES: biostudies-literature

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First experience of 18F-alfatide in lung cancer patients using a new lyophilized kit for rapid radiofluorination.

Wan Weixing W Guo Ning N Pan Donghui D Yu Chunjing C Weng Yuan Y Luo Shineng S Ding Hong H Xu Yuping Y Wang Lizhen L Lang Lixin L Xie Qingguo Q Yang Min M Chen Xiaoyuan X

Journal of nuclear medicine : official publication, Society of Nuclear Medicine 20130403 5

<h4>Unlabelled</h4>(18)F-FPPRGD2, which was approved for clinical study recently, has favorable properties for integrin targeting and showed potential for antiangiogenic therapy and early response monitoring. However, the time-consuming multiple-step synthesis may limit its widespread applications in the clinic. In this study, we developed a simple lyophilized kit for labeling PRGD2 peptide ((18)F-AlF-NOTA-PRGD2, denoted as (18)F-alfatide) using a fluoride-aluminum complex that significantly sim ...[more]

PMID: 23554506

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Project description:Radiolabeling compounds with positron-emitting radionuclides often involves a time-consuming, customized process. Herein, we report a simple lyophilized kit formulation for labeling peptides with (18)F, based on the aluminum-fluoride procedure. The prototype kit contains IMP485, a NODA (1,4,7-triazacyclononane-1,4-diacetate)-MPAA (methyl phenylacetic acid)-di-HSG (histamine-succinyl-glycine) hapten-peptide, [NODA-MPAA-D-Lys(HSG)-D-Tyr-D-Lys(HSG)-NH(2)], used for pretargeting, but we also examined a similar kit formulation for a somatostatin-binding peptide [IMP466, NOTA-D-Phe-Cys-Phe-D-Trp-Lys-Thr-Cys-Throl] bearing a NOTA ligand to determine if the benefits of using a kit can be extended to other AlF-binding peptides. The NODA-MPAA ligand forms a single stable complex with (AlF)(2+) in high yields. In order to establish suitable conditions for a facile kit, the formulation was optimized for pH, peptide to Al(3+) ratio, bulking agent, radioprotectant, and the buffer. For optimal labeling, the kit was reconstituted with an aqueous solution of (18)F(-) and ethanol (1:1), heated at 100-110 °C for 15 min, and then simply and rapidly purified using one of two equally effective solid-phase extraction (SPE) methods. Al(18)F-IMP485 was isolated as a single isomer complex, in high yield (45-97%) and high specific activity (up to 223 GBq/?mol), within 20 min. The labeled product was stable in human serum at 37 °C for 4 h and in vivo, urine samples showed the intact product was eliminated. Tumor targeting of the Al(18)F-IMP485 in nude mice bearing human colon cancer xenografts pretargeted with an anti-CEACAM5 bispecific antibody showed very low uptake (0.06% ± 0.02 ID/g) in bone, further illustrating its stability. At 1 h, pretargeted animals had high Al(18)F-IMP485 tumor uptake (28.1% ± 4.5 ID/g), with ratios of 9 ± 4, 123 ± 38, 110 ± 43, and 120 ± 108 for kidney, liver, blood and bone, respectively. Tumor uptake remained high at 3 h postinjection, with increased tumor/nontumor ratios. The NOTA-somatostatin-binding peptide also was fluorinated with good yield and high specific activity in the same kit formulation. However, yields were somewhat lower than those achieved with IMP485 containing the NODA-MPAA ligand, likely reflecting this ligand's superior binding properties over the simple NOTA. These studies indicate that (18)F-labeled peptides can be reproducibly prepared as stable Al-F complexes with good radiochemical yield and high specific activity using a simple, one-step, lyophilized kit followed by a rapid purification by SPE that provides the (18)F-peptide ready for patient injection within 30 min.

Project description:Aim(18)F-DPA-714 is a PET tracer that recognizes macrophage translocator protein (TSPO), and (18)F-Alfatide II ((18)F-AlF-NOTA-E[PEG4-c(RGDfk)]2) is specific for integrin αvβ3. This study aims to apply these two tracers for longitudinal PET imaging of muscular inflammation, and evaluate the value of (18)F-DPA-714 in differentiating inflammation from tumor.MethodsRAW264.7 mouse macrophage cells were used for cell uptake analysis of (18)F-DPA-714. A mouse hind limb muscular inflammation model was established by intramuscular injection of turpentine oil. For the inflammation model, PET imaging was performed at different days using (18)F-DPA-714 and (18)F-Alfatide II. The specificity of the imaging probes was tested by co- or pre-injection of PK11195 or unlabeled RGD (Arg-Gly-Asp) peptide. PET imaging using (18)F-DPA-714 was performed in A549, HT29, U87MG, INS-1, and 4T1 xenograft models. Immunofluorescence staining was performed to evaluate infiltrated macrophages and angiogenesis in inflammation and/or tumors.ResultsUptake of (18)F-DPA-714 in RAW264.7 cells was 45.5% at 1 h after incubation, and could be blocked by PK11195. PET imaging showed increased (18)F-DPA-714 and (18)F-Alfatide II uptake at inflammatory muscles. Peak uptake of (18)F-DPA-714 was seen on day 6 (4.02 ± 0.64 %ID/g), and peak uptake of (18)F-Alfatide II was shown on day 12 (1.87 ± 0.35 %ID/g) at 1 h p.i.. Tracer uptakes could be inhibited by PK11195 for (18)F-DPA-714 or cold RGD for (18)F-Alfatide II. Moreover, macrophage depletion with liposomal clodronate also reduced the local accumulation of both tracers. A549, HT29, U87MG, INS-1, and 4T1 tumor uptakes of (18)F-DPA-714 (0.46 ± 0.28, 0.91 ± 0.08, 1.69 ± 0.67, 1.13 ± 0.33, 1.22 ± 0.55 %ID/g at 1 h p.i., respectively) were significantly lower than inflammation uptake (All P < 0.05).ConclusionPET imaging using (18)F-DPA-714 as a TSPO targeting tracer could evaluate the dynamics of macrophage activation and infiltration in different stages of inflammatory diseases. The concomitant longitudinal PET imaging with both (18)F-DPA-714 and (18)F-Alfatide II matched the causal relationship between macrophage infiltration and angiogenesis. Moreover, we found (18)F-DPA-714 uptake in several types of tumors is significantly lower than that in inflammatory muscles, suggesting (18)F-DPA-714 PET has the potential for better differentiation of tumor and non-tumor inflammation.

Project description:Prostate-specific membrane antigen (PSMA)-targeted PET imaging for prostate cancer with 68Ga-labeled compounds has rapidly become adopted as part of routine clinical care in many parts of the world. However, recent years have witnessed the start of a shift from 68Ga- to 18F-labeled PSMA-targeted compounds. The latter imaging agents have several key advantages, which may lay the groundwork for an even more widespread adoption into the clinic. First, facilitated delivery from distant suppliers expands the availability of PET radiopharmaceuticals in smaller hospitals operating a PET center but lacking the patient volume to justify an onsite 68Ge/68Ga generator. Thus, such an approach meets the increasing demand for PSMA-targeted PET imaging in areas with lower population density and may even lead to cost-savings compared to in-house production. Moreover, 18F-labeled radiotracers have a higher positron yield and lower positron energy, which in turn decreases image noise, improves contrast resolution, and maximizes the likelihood of detecting subtle lesions. In addition, the longer half-life of 110 min allows for improved delayed imaging protocols and flexibility in study design, which may further increase diagnostic accuracy. Moreover, such compounds can be distributed to sites which are not allowed to produce radiotracers on-site due to regulatory issues or to centers without access to a cyclotron. In light of these advantageous characteristics, 18F-labeled PSMA-targeted PET radiotracers may play an important role in both optimizing this transformative imaging modality and making it widely available. We have aimed to provide a concise overview of emerging 18F-labeled PSMA-targeted radiotracers undergoing active clinical development. Given the wide array of available radiotracers, comparative studies are needed to firmly establish the role of the available 18F-labeled compounds in the field of molecular PCa imaging, preferably in different clinical scenarios.

Dataset Information

First experience of 18F-alfatide in lung cancer patients using a new lyophilized kit for rapid radiofluorination.

Publications

First experience of 18F-alfatide in lung cancer patients using a new lyophilized kit for rapid radiofluorination.

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