Ludger Dinkelborg

• PhD
• Managing Director at Life Molecular Imaging

Background The PET tracer (4S)-4-(3-[18F]fluoropropyl)-l-glutamate (18F-FSPG) targets the system xC- cotransporter, which is overexpressed in various tumors. Purpose To assess the role of 18F-FSPG PET/CT in intracranial malignancies. Materials and Methods Twenty-six patients (mean age, 54 years ± 12; 17 men; 48 total lesions) with primary brain tum...

Tau aggregates represent a critical pathology in Alzheimer’s disease (AD) and other forms of dementia. The extent of Tau neurofibrillary tangles across defined brain regions corresponds well to the observed level of cognitive decline in AD. Compound 1 (PI-2620) was recently identified as a promising Tau positron emission tomography tracer for AD an...

The compound screening was initiated with a direct staining assay to identify compounds binding to Tau aggregates and not Abeta plaques using human brain sections derived from late stage Alzheimer's disease donors. The binding of Tau aggregate selective compounds was then quantitatively assessed with human brain derived paired helical filaments uti...

18F-PI-2620 is a next generation tau positron emission tomography (PET)-tracer that has demonstrated ability to image the spatial distribution of suspected tau pathology. The objective of this study was to assess the tracer biodistribution, dosimetry and quantitative methods of 18F-PI-2620 in the human brain. Full kinetic modelling approaches to qu...

18F-PI-2620 is a positron emission tomography (PET) tracer with high binding affinity for aggregated tau, a key pathologic feature of Alzheimer's disease (AD) and other neurodegenerative disorders. Preclinically, 18F-PI-2620 binds to both, 3R and 4R tau isoforms. The purpose of this first-in-human study was to evaluate the ability of 18F-PI-2620 to...

Purpose Tau deposition is a key pathological feature of Alzheimer’s disease (AD) and other neurodegenerative disorders. The spreading of tau neurofibrillary tangles across defined brain regions corresponds to the observed level of cognitive decline in AD. Positron-emission tomography (PET) has proved to be an important tool for the detection of amy...

Introduction: 18F-florbetaben is currently approved for the visual rule out of β-amyloid (Aβ) pathology. It is also used for recruitment and as an outcome measure in therapeutic trials, requiring accurate and reproducible quantification of Aβ burden in the brain. Methods: Data from eighty-eight subjects (52 male subjects, aged 79.8 ± 10.6 years)...

Thrombus formation can lead to heart attacks, stroke and pulmonary embolism, which are major causes of mortality. Current standard diagnostic imaging methods detect anatomic abnormalities such as vascular flow impairment but have limitations. By using a targeted molecular imaging approach critical components of a pathology can be selectively visual...

Purpose: The Centiloid (CL) method enables quantitative values from Aβ-amyloid (Aβ) imaging to be expressed in a universal unit providing pathological, diagnostic and prognostic thresholds in clinical practice and research and allowing integration of multiple tracers and methods. The method was developed for (11)C-PiB scans with zero CL set as the...

Molecular imaging biomarkers offer the unique possibility for earlier disease detection and better characterisation, as well as enabling of drug development. Addressing a relevant biomedical question, selecting the right target and the optimisation of ligand binding as well as pharmacokinetic parameters in preclinical models are the crucial steps b...

Thromboembolic diseases such as myocardial infarction, stroke, transient ischemic attacks and pulmonary embolism are major causes of morbidity and mortality worldwide. GPIIb/IIIa is the key receptor involved in platelet aggregation and is a validated target for therapeutic approaches and diagnostic imaging. The aim of this study was to develop and...

Purpose: (S)-4-(3-[18F]Fluoropropyl)-L-glutamic acid (18F-FSPG) is a novel radiopharmaceutical for Positron Emission Tomography (PET) imaging. It is a glutamate analogue that can be used to measure xC- transporter activity. This study was performed to assess the feasibility of 18F-FSPG for imaging orthotopic brain tumors in small animals and the t...

TREND Checklist. (PDF)

Specific inclusion and exclusion criteria for enrollment in the human 18F-FSPG PET/CT imaging trial. (DOCX)

Average and standard deviation (S.D.) values for subjects’ vital signs, blood hematologies, and blood chemistries before injection of 18F-FSPG, after completion of imaging (approximately 3 hours post-injection), and the next day (approximately 24 hours post-injection). (DOCX)

Time-activity curves of 18F-FSPG (SUV mean in g/ml) for various normal organs for all five subjects. Each data point represents the mean value with standard deviations across all subjects. There is a gradual decrease in activity in all normal organs except for the pancreas. The values are decay-corrected. (TIFF)

Time-activity curves of 18F-FSPG (SUV mean in g/ml) for primary and metastatic brain tumor lesions from all five patients. The brain lesions show a gradual increase in activity until 30 minutes then decreasing minimally. The only exception is Subject 2 with the low-grade oligodendroglioma who had no uptake. (TIFF)

Time-activity curves of 18F-FSPG (SUV mean in g/ml) for various non-brain primary and metastatic lesions for two patients who had them. The active primary lung tumor and bone metastases for Subject 3 showed continually increasing activity over the time-course of imaging. The treated primary lung tumor and inflammatory lymph nodes for Subject 4 show...

Study Protocol. (PDF)

The comparison of the 18F-FSPG, 18F-FET and 18F-FDG uptake in blood, normal brain and brain tumor as well as analyses of tumor-to normal brain and tumor-to-blood ratios. Significant differences are marked in bold. (DOCX)

Purpose: Carbon-11- and fluorine-18-labeled choline derivatives are commonly used in prostate cancer imaging in the clinical setting for staging and re-staging of prostate cancer. Due to a limited detection rate of established positron emission tomography (PET) tracers, there is a clinical need for innovative tumor-specific PET compounds addressin...

Methods: In ten patients with various inflammatory/infectious diseases, as many as five of the largest inflammatory lesions were selected as reference lesions. (18)F-FSPG images were assessed visually and quantitatively. Expression levels of xCT, CD44, and surface markers of inflammatory cells were evaluated by immunohistochemistry. Results: (18...

Piramal Imaging, a division of Piramal Enterprises Ltd, is a global radiopharmaceutical company that is actively developing novel PET radiotracers for use in molecular imaging. The company focuses on developing innovative products that improve early detection and characterization of chronic and life-threatening diseases, leading to better therapeut...

The extracellular matrix protein ED-B fibronectin (ED-B) is upregulated in inflammatory atherosclerotic lesions. However, functional in vivo imaging of ED-B-containing plaques has not been explored. This study evaluated whether [99mTc]-conjugated AP39 ([99mTc]-AP39), a single-chain antibody specific to ED-B, can be used for in vivo detection of ath...

The aim of this "first in man" study was to demonstrate the feasibility, safety and tolerability, as well as to provide dosimetric data and to evaluate the imaging properties in a small group of patients of the Bombesin analogue BAY 864367 PET/CT in patients with primary and recurrent prostate cancer (PCa). Ten patients with biopsy proven PCa (n =...

Purpose: (2RS,4S)-2-[(18)F]Fluoro-4-phosphonomethyl-pentanedioic acid (BAY1075553) shows increased uptake in prostate cancer cells. We compared the diagnostic potential of positron emission tomography (PET)-X-ray computed tomography (CT) imaging using BAY1075553 versus [(18)F]f luorocholine (FCH) PET-CT. Procedures: Twelve prostate cancer patien...

UNLABELLED: (d)-(18)F-fluoromethyltyrosine (d-(18)F-FMT), or BAY 86-9596, is a novel (18)F-labeled tyrosine derivative rapidly transported by the l-amino acid transporter (LAT-1), with a faster blood pool clearance than the corresponding l-isomer. The aim of this study was to demonstrate the feasibility of tumor detection in patients with non-small...

Purpose 18F-Florbetaben is a positron emission tomography (PET) tracer indicated for imaging cerebral beta-amyloid deposition in adult patients with cognitive impairment who are being evaluated for Alzheimer’s disease and other causes of cognitive decline. The present study examined ethnic comparability of the plasma pharmacokinetics, which is the...

Introduction Atherosclerotic plaque rupture is the primary cause for myocardial infarction and stroke. During plaque progression macrophages and mast cells secrete matrix-degrading proteolytic enzymes, such as matrix metalloproteinases (MMPs). We studied levels of MMPs and tissue inhibitor of metalloproteinases-3 (TIMP-3) in relation to the charact...

Background We assessed the clinical utility of β-amyloid (Aβ) imaging with 18F-florbetaben (FBB) in mild cognitive impairment (MCI) by evaluating its prognostic accuracy for progression to Alzheimer's disease (AD), comparing semiquantitative with visual scan assessment, and exploring the relationships among Aβ, hippocampal volume (HV) and memory ov...

The radiosynthesis of [(18) F]fluoropyruvate was investigated using numerous precursors were synthesized from ethyl 2,2-diethoxy-3-hydroxypropanoate (5) containing different leaving groups: mesylate, tosylate, triflate, and nonaflate. These precursors were evaluated for [(18) F]fluoride incorporation with triflate being superior. The subsequent hyd...

Silicon-containing prosthetic groups have been conjugated to peptides to allow for a single-step labeling with (18)F radioisotope. The fairly lipophilic di-tert-butylphenylsilane building block contributes unfavorably to the pharmacokinetic profile of the bombesin radiotracer. In this article, theoretical and experimental studies towards the develo...

Prostate-specific membrane antigen (PSMA) is a transmembrane protein overexpressed in prostate cancer and is therefore being explored as a biomarker for diagnosing and staging of the disease. Here we report preclinical data on BAY 1075553 (a 9:1 mixture of (2S,4S)- and (2R,4S)-2-[(18)F]fluoro-4-phosphonomethyl-pentanedioic acid), a novel (18)F-labe...

Novel tracers for the diagnosis of malignant disease with PET and PET/CT are being developed as the most commonly used (18)F deoxyglucose (FDG) tracer shows certain limitations. Employing radioactively labelled glutamate derivatives for specific imaging of the truncated citrate cycle potentially allows more specific tumour imaging. Radiation dosime...

Fluorine-18 labeled (2S,4S)-2-[18F]fluoro-4-(phosphonomethyl)pentanedioic acid (BAY 1075553) has been identified as a prostate specific membrane antigen inhibitor ligand and is being investigated in clinical PET studies for its application in the diagnosis and staging of prostate cancer. To facilitate its transfer to the clinics, it was imperative...

The activity of matrix metalloproteinases (MMPs) is elevated locally under many pathological condi-tions. Gelatinases MMP2 and MMP9 are of particular interest because of their implication in angiogen-esis, cancer cell proliferation and metastasis, and atherosclerotic plaque rupture. The aim of this study was to identify and develop a selective gela...

Unlabelled: The glutamic acid derivative (S)-4-(3-(18)F-Fluoropropyl)-l-glutamic acid ((18)F-FSPG, alias BAY 94-9392), a new PET tracer for the detection of malignant diseases, displayed promising results in non-small cell lung cancer patients. The aim of this study was to provide dosimetry estimates for (18)F-FSPG based on human whole-body PET/CT...

Unlabelled: (4S)-4-(3-(18)F-fluoropropyl)-l-glutamate ((18)F-FSPG, or BAY 94-9392) is a new tracer to assess system x(C)(¯) transporter activity with PET. The aim of this study was to explore the tumor detection rate of (18)F-FSPG, compared with that of (18)F-FDG, in patients with hepatocellular carcinoma (HCC). Methods: Preclinically, in vivo H...

The [(18)F]fluorocyclobutyl group has the potential to be a metabolically stable prosthetic group for PET tracers. The synthesis of the radiolabeling precursor cis-cyclobutane-1,3-diyl bis(toluene-4-sulfonate) 8 was obtained from epibromohydrin in 7 steps (2% overall yield). The radiolabeling of this precursor 8 and its conjugation to l-tyrosine as...

For prostate cancer, prostate specific membrane antigen (PSMA) has been identified as a diagnostic and therapeutic target. Fluorinated derivatives of 2-(phosphonomethyl)pentanedioic acid were designed and synthesized to explore whether this fluorine-substituent is tolerated in the pentanedioic acid moiety that is common to almost all PSMA targeting...

Unlabelled: Imaging of amyloid-β (Aβ) plaques by PET is more and more integrated into concepts for Alzheimer disease (AD) diagnosis and drug development. The objective of this study was to find novel chemical entities that can be transformed into (18)F-labeled Aβ tracers with favorable brain washout kinetics and low background signal. Methods: H...

(4S)-4-(3-[(18)F]fluoropropyl)-l-glutamate (BAY 94-9392, alias [(18)F]FSPG) is a new tracer to image x(C)(-) transporter activity with positron emission tomography (PET). We aimed to explore the tumor detection rate of [(18)F]FSPG in patients relative to 2-[(18)F]fluoro-2-deoxyglucose ([(18)F]FDG). The correlation of [(18)F]FSPG uptake with immunoh...

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL Purpose Radiolabeled tryptophan is capable of visualizing the amino acid metabolism of tumor cells. We investigated the indirectly labeled derivative L-5-F-18-ethoxy-Trp for its potential to differentiate tumors from inflammation by Positron-Emission-Tomography (PET) and...

Visualizing adaptations of tumor metabolism by employing positron emission tomography (PET) with a specific imaging probe has the potential to better characterize tumors with higher sensitivity and specificity. The glutamate-cystine exchanger (system xC-, a SLC7A11/SLC3A2 heterodimer) is an important transporter in tumor cells and a promising new t...

Purpose: Amyloid-β (Aβ) plaques are a major pathological hallmark of Alzheimer's disease (AD). The noninvasive detection of Aβ plaques may increase the accuracy of clinical diagnosis as well as monitor therapeutic interventions. While [(11)C]-PiB is the most widely used Aβ positron emission tomography (PET) radiotracer, due to the short half-life...

A new method for the 18F-radiolabeling of aromatic compounds based on the aromatic nucleophilic substitution (SNAr) reaction using triarylsulfonium salts has been developed. Experiments and DFT calculations indicated that sulfonium ions have the potential to be optimized for labeling nonactivated and deactivated aryl rings that have Hammett σP subs...

F18 2-Fluoro 2-deoxyglucose (FDG) has been the gold standard in positron emission tomography (PET) oncologic imaging since its introduction into the clinics several years ago. Seeking to complement FDG in the diagnosis of breast cancer using radio labeled fructose based analogs, we investigated the expression of the chief fructose transporter-GLUT...

(18)F-labeled small molecules targeting adaptations of tumor metabolism possess the potential for early tumor detection with high sensitivity and specificity by positron emission tomography (PET) imaging. Compounds tracing deranged pathways other than glycolysis may have advantages in situations where 2-[¹⁸F]fluoro-2-deoxy-d-glucose (FDG) has limit...

There is a high demand for a tumor specific imaging, staging and therapy monitoring by PET. Currently, FDG (2-[F-18]fluoro-2-deoxyglucose) is the commonly used agent for tumor detection and staging. However, this method cannot differentiate between tumor and inflammatory lesions. In addition, FDG does not accumulate in tumors with low glycolytic ac...

Bombesin is a peptide exhibiting high affinity for the gastrin-releasing peptide receptor (GRPr), which is highly overexpressed on prostate cancer cells. In the present study, we developed an (18)F-labeled bombesin analog, (18)F-BAY 86-4367, which is currently being clinically tested for use in PET of prostate cancer. In vitro pharmacologic studies...

There is a high demand for tumor specific PET tracers in oncology imaging. Besides glucose, certain amino acids also serve as energy sources and anabolic precursors for tumors. Therefore, (18)F-labeled amino acids are interesting probes for tumor specific PET imaging. As glutamine and glutamate play a key role in the adapted intermediary metabolism...

The gastrin-releasing peptide receptor (GRPR) is overexpressed on a number of human tumors and has been targeted with radiolabeled bombesin analogues for the diagnosis and therapy of these cancers. Seven bombesin analogues containing various linkers and peptide sequences were designed, synthesized, radiolabeled with (18)F, and characterized in vitr...

Radiolabeled benzamides are attractive candidates for targeted radiotherapy of metastatic melanoma as they bind melanin and exhibit high tumor uptake and retention. One such benzamide, N-(2-diethylamino-ethyl)-4-(4-fluoro-benzamido)-5-iodo-2-methoxy-benzamide (MIP-1145), was evaluated for its ability to distinguish melanin-expressing from amelanoti...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The extracellular matrix protein ED-B fibronectin (ED-B) is upregulated in inflammatory atherosclerotic lesions and is associated with local macrophage accumulation. In the present study we evaluated whether a conjugate of 99mTc with the single chain antibody against ED-B (99mTC-anti-ED-B) can be used for in vivo detection of atherosclerotic plaque...

Methods for the radiolabeling molecules of interest with [18F]-fluoride need to be rapid, convenient, and efficient. Numerous [18F]-labeled prosthetic groups, e.g., N-succinimidyl 4 [18F]-fluorobenzoate ([18F]-SFB), 4-azidophenacyl-[18F]-fluoride ([18F]-APF), and 1-(3-(2-[18F]fluoropyridin-3-yloxy)propyl)pyrrole-2,5-dione ([18F]-FpyMe), for conjuga...

The direct labeling of biomolecules with fluorine-18 is highly desirable. An option is the ring-opening of an activated aziridine moiety in a biomolecule using 18F-fluoride. Therefore, a series of aziridine-based model compounds and three aziridine-based biomolecules four aziridine-based model compounds were synthesized and evaluated as potential p...

The detection of human epidermal growth factor receptor type 2 (HER2) expression in malignant tumors provides important information influencing patient management. Radionuclide in vivo imaging of HER2 may permit the detection of HER2 in both primary tumors and metastases by a single noninvasive procedure. Small (7 kDa) high-affinity anti-HER2 Affib...

Purpose The human monoclonal antibody (MAb) fragment L19-SIP is directed against extra domain B (ED-B) of fibronectin, a marker of tumour angiogenesis. A clinical radioimmunotherapy (RIT) trial with 131I-L19-SIP was recently started. In the present study, after GMP production of 124I and efficient production of 124I-L19-SIP, we aimed to demonstrate...

Beta-amyloid (Abeta) imaging has great potential to aid in the diagnosis of Alzheimer disease and the development of therapeutics. The radiation dosimetry of Abeta radioligands may influence their application; therefore, we calculated and compared the effective doses (EDs) of 11C-PiB and a new 18F-labeled ligand, 18F-BAY94-9172. Attenuation-correct...

The gastrin-releasing peptide receptor (GRPr) is overexpressed on various human tumors. The goal of our study was the synthesis of new 18F-labeled bombesin analogues for the PET imaging of GRPr expression in prostate tumor using a silicon-based one-step n. c. a. radiolabeling method. The silicon-containing building blocks were efficiently coupled t...

Molecular imaging can allow the non-invasive assessment of biological and biochemical processes in living subjects. Such technologies therefore have the potential to enhance our understanding of disease and drug activity during preclinical and clinical drug development, which could aid decisions to select candidates that seem most likely to be succ...

The successful use of peptides as potential radiopharmaceuticals essentially requires the modification of the bioactive peptide hormones to introduce chelators for radiolabeling. In this study, four Y 1/Y 2 receptor-selective NPY analogues with different receptor subtype specificities have been investigated. For in vitro studies, the cold metal sur...

Landeplatz für Fluor: Durch einen einstufigen Ansatz gelingt die einfache 18F-Markierung von Biomolekülen über Siliciumgruppen unter milden Bedingungen (siehe Schema). Ein Di-tert-butylsilyl-Derivat mit Aryllinker wurde an ein Tetrapeptid angehängt. Das Konstrukt wies eine Hydrolysebeständigkeit auf, die einen Einsatz in der Positronenemissionstomo...

(Equation Presented) Radio-controlled landing of F: The facile 18F labeling of biomolecules has been achieved under mild conditions by using a unique silicon-based one-step approach (see scheme). A di-tert-butylsilyl derivative with an aryl linker was attached to a tetrapeptide. The assembly shows a hydrolytic stability that appears to be within th...

Amyloid-beta (Abeta) plaque formation is a hallmark of Alzheimer's disease (AD) and precedes the onset of dementia. Abeta imaging should allow earlier diagnosis, but clinical application is hindered by the short decay half-life of current Abeta-specific ligands. (18)F-BAY94-9172 is an Abeta ligand that, due to the half-life of (18)F, is suitable fo...

The technetium 99 m (99mTc)-radiolabeled, leukocyte-avid peptide-glycoseaminoglycan complex, [99mTc]P1827DS, has been synthesized as an improved infection/inflammation imaging agent to [99mTc]P483H (LeukoTect, Diatide). In a phase I/II clinical trail, [99mTc]P483H images were equivalent to those obtained with 111In ex vivo labeled leukocytes. Howev...

The aim of this study was to image the extra domain B (ED-B) of fibronectin, an angiogenesis-related target, in solid tumors using small-animal PET. Toward this aim, an ED-B fibronectin-binding human antibody derivative (L19-SIP) was labeled with (76)Br via an enzymatic approach. Biodistribution and imaging studies were performed in human teratoma-...

Somatostatin derivative peptides previously designed for radiodiagnostic purposes (99mTc P829 or 99mTc depreotide) were reoptimized for radiotherapy of tumors with rhenium radioisotopes. An optimized pharmacophore peptide P1839 was derived by in vitro binding affinity assay to AR42J rat pancreatic tumor cell membranes. Peptides with chelating domai...

The aim of this study was to target the angiogenesis-associated extracellular matrix protein ED-B fibronectin for molecular imaging of solid tumors. Recombinant and chemically modified derivatives of the single-chain antibody fragment (scFv) L19, capable of being labeled with 99mTc, were synthesized and radiolabeled. The resulting compounds 99mTc-A...

Extra domain B (ED-B) fibronectin is a specific tumor matrix marker for targeting angiogenesis in solid tumors. In this study, the radiotherapeutic potential of the directly radioiodinated divalent anti-ED-B antibody fragment, L19 small immunoprotein (L19-SIP; 75,000 Da), was compared with a pretargeting approach using the bispecific antibody AP39x...

Objective: The human monoclonal antibody L19-SIP is directed against the extra domain B of fibronectin (ED-B), a marker of tumor angiogenesis. The potential of radioimmunotherapy (RIT) with L19-SIP was evaluated, either alone or in combination with the anti–epidermal growth factor receptor (EGFR) antibody cetuximab, for treatment of head and neck s...

The extra domain B of fibronectin (ED-B) is a marker of tumor angiogenesis. The human monoclonal antibody (mAb) L19-SIP (approximately 80 kDa; SIP is "small immunoprotein") has been selected for targeting of ED-B. The aim of this study was to evaluate the potential of radioimmunotherapy (RIT) with L19-SIP, either alone or in combination with cetuxi...

The aim of this study was to first calculate the dose-enhancement effect from internalized radiation by the presence of exogenous contrast media using Monte Carlo simulations, and then provide in vitro proof-of-concept for this novel method of radiation-dose enhancement. The Monte Carlo program EGSnrc (Electron Gamma Shower) was used to simulate th...

In Vivo Imaging: Modalities and Requirements Imaging ModalitiesRequirements for ImagingAptamers for In Vivo Imaging Oligonucleotide Properties for In Vivo ApplicationsComparison of Different Classes of Targeting AgentsAptamer Targets for ImagingLabeling of Aptamers SPECT IsotopesPET IsotopesOligonucleotides in SPECT and PET Imaging Non-targeting Ap...

To test the feasibility of self-expanding drug-coated nitinol stents for prevention of restenosis in an animal model. Stent implantation in the carotid artery (CA) has been shown to be feasible for treatment of CA stenosis. Even though the restenosis rate in CA is reported to be lower than in the coronary and peripheral arteries, problems may arise...

The expression of extra domain B (ED-B) fibronectin is always associated with angiogenic processes and can be exclusively observed in tissues undergoing growth and/or extensive remodeling. Due to this selective expression, ED-B fibronectin is an interesting target for radioimmunotherapy of malignant diseases. The aim of this study was to identify t...