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"Geis, Nicolas M."
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Development and preclinical characterization of a novel radiotheranostic EphA2-targeting bicyclic peptide
2024
Erythropoietin-producing hepatocellular receptor A2 (EphA2), is a receptor tyrosine kinase involved in cell-cell interactions. It is known to be overexpressed in various tumors and is associated with poor prognosis. EphA2 has been proposed as a target for theranostic applications. Low molecular weight peptide-based scaffolds with low nanomolar affinities have been shown to be ideal in such applications. Bicyclic peptides have emerged as an alternative to traditional peptides for this purpose, offering affinities comparable to antibodies due to their constrained nature, along with high tissue penetration, and improved stability compared to linear counterparts. This study presents the development and comprehensive
and
preclinical evaluation of BCY18469, a novel EphA2-targeting bicyclic peptide-based radiotheranostic agent.
The EphA2-targeting Bicycle
peptide BCY18469 was identified through phage-display and chemically optimized. BCY18469 was radiolabeled with
Ga,
Lu and
In. The physicochemical properties, binding affinity and internalization as well as specificity of the peptide were evaluated
.
PET/MR and SPECT/CT imaging studies were performed using [
Ga]Ga-BCY18469 and [
In]In-BCY18469, respectively, along with biodistribution of [
Lu]Lu-BCY18469 up to 24 h post injection in HT1080- and PC-3-tumor bearing BALB/c nu/nu EphA2-overexpressing xenograft mouse models.
The EphA2-targeting bicyclic peptide BCY18469 showed high binding affinity toward human and mouse EphA2 (1.9 and 3.8 nM, respectively). BCY18469 specifically bound and internalized into EphA2-expressing HT1080 cells. Imaging studies showed high tumor enrichment at early time-points (SUV of 1.7 g/mL at 1 h p.i. and 1.2 g/mL at 2 h p.i. in PET/MRI, HT1080 xenograft) with tumor contrast as early as 5 min p.i. and kidney-mediated clearance. Biodistribution studies revealed high early tumor uptake (19.5 ± 3.5 %ID/g at 1 h p.i., HT1080 xenograft) with SPECT/CT imaging further confirming these findings (5.7 ± 1.5 %ID/g at 1 h p.i., PC-3 xenograft).
BCY18469 demonstrated high affinity, specific targeting of EphA2, a favorable biodistribution profile, and clearance through renal pathways. These findings underscore the potentially important role of bicyclic peptides in advancing radiotheranostic approaches and encourage additional translational research.
Journal Article
PSMA-Targeting Radiopharmaceuticals for Prostate Cancer Therapy: Recent Developments and Future Perspectives
by
Eder, Matthias
,
El Fakiri, Mohamed
,
Geis, Nicolas M.
in
Adenocarcinoma
,
Amino acids
,
Binding sites
2021
Prostate cancer (PC) is the second most common cancer among men, with 1.3 million yearly cases worldwide. Among those cancer-afflicted men, 30% will develop metastases and some will progress into metastatic castration-resistant prostate cancer (mCRPC), which is associated with a poor prognosis and median survival time that ranges from nine to 13 months. Nevertheless, the discovery of prostate specific membrane antigen (PSMA), a marker overexpressed in the majority of prostatic cancerous tissue, revolutionised PC care. Ever since, PSMA-targeted radionuclide therapy has gained remarkable international visibility in translational oncology. Furthermore, on first clinical application, it has shown significant influence on therapeutic management and patient care in metastatic and hormone-refractory prostate cancer, a disease that previously had remained immedicable. In this article, we provide a general overview of the main milestones in the development of ligands for PSMA-targeted radionuclide therapy, ranging from the firstly developed monoclonal antibodies to the current state-of-the-art low molecular weight entities conjugated with various radionuclides, as well as potential future efforts related to PSMA-targeted radionuclide therapy.
Journal Article
Optimizing PSMA-617-based inhibitors through charged linker modifications: Insights into structure-activity relationships
by
Meyer, Phillip T.
,
Braunwarth, Yvonne
,
Eder, Matthias
in
Animals
,
Antigens, Surface - metabolism
,
Cell Line, Tumor
2026
The introduction of Pluvicto
([
Lu]Lu-vipivotide tetraxetan; [
Lu]Lu-PSMA-617) marks a milestone in radioligand therapy (RLT) for PSMA-positive metastatic castration-resistant prostate cancer (mCRPC). While dose escalation of [
Lu]Lu-PSMA-617 and alpha-emitting agents like [
Ac]Ac-PSMA-617 improves efficacy, it is limited by dose-dependent toxicity in critical organs, including kidneys, bone marrow and salivary glands. Modifications of the linker region in PSMA inhibitors have been proven to highly influence the pharmacokinetic profile. The utilization of charged linker moieties resulted in clinically used PSMA-targeting radiotracers such as [
F]PSMA-1007. This study explores histidine and/or glutamic acid-modified variants of PSMA-617 to investigate their effects on pharmacokinetic properties.
Based on the core structure of PSMA-617, eleven novel PSMA-targeting inhibitors were synthesized by introducing histidine and/or glutamic acid moieties at three positions within the linker region. Compounds were radiolabeled with [
Ga]Ga
and [
Lu]Lu
to assess their chemical and stability properties. Biological activity was evaluated in competitive cell binding and internalization assays with PSMA-expressing LNCaP cells. Dynamic and static small-animal PET imaging studies were conducted with the
Ga-labeled inhibitors in LNCaP bearing BALB/c nu/nu xenografts to investigate their pharmacokinetic profiles.
Precursors of linker-modified PSMA inhibitors presented high radiochemical purities (RCPs) for the complexation reactions with both radionuclides (>94%).
Ga-labeled compounds demonstrated significantly lower lipophilicity (ranging from -3.4 to -3.9) compared to the reference compound [
Ga]Ga-PSMA-617 (-2.8 ± 0.3). Substantial effects on the affinity to PSMA were observed depending on the position and nature of modification (IC
ranging from 10.40 ± 2.94 nM to 78.6 ± 44.1 nM). Modification with glutamic acid adjacent to the chelator resulted in a two-fold increase in affinity, while variants containing histidine and glutamic acid led to significant improvements in cell surface binding and internalization (
< 0.05). Dynamic small-animal PET scans with the novel
Ga-labeled variants revealed an improved accumulation in LNCaP xenograft tumors (SUV
: 0.21 ± 0.05 to 1.32 ± 0.08 g/ml) accompanied by a fast clearance from the kidneys and background tissue within the initial 60 min. Static PET scans 2 h p.i. confirmed a high tumor uptake and a rapid renal excretion.
The introduction of histidine and/or glutamic acid moieties into the linker region of PSMA-617 resulted in measurable changes in pharmacokinetic properties both
and
. While some modifications led to improved tumor-to-kidney ratios and favorable early-stage excretion, it remains challenging to predict clinical off-targeting effects like salivary gland uptake. This study provides important insights into the structure-activity relationships of PSMA-617-related linker modifications and warrant additional investigation, including mechanistic and translational studies, to more accurately evaluate their therapeutic potential.
Journal Article
A distributable German clinical corpus containing cardiovascular clinical routine doctor’s letters
2023
We present CARDIO:DE, the first freely available and distributable large German clinical corpus from the cardiovascular domain. CARDIO:DE encompasses 500 clinical routine German doctor’s letters from Heidelberg University Hospital, which were manually annotated. Our prospective study design complies well with current data protection regulations and allows us to keep the original structure of clinical documents consistent. In order to ease access to our corpus, we manually de-identified all letters. To enable various information extraction tasks the temporal information in the documents was preserved. We added two high-quality manual annotation layers to CARDIO:DE, (1) medication information and (2) CDA-compliant section classes. To the best of our knowledge, CARDIO:DE is the first freely available and distributable German clinical corpus in the cardiovascular domain. In summary, our corpus offers unique opportunities for collaborative and reproducible research on natural language processing models for German clinical texts.
Journal Article
Automatic extraction of 12 cardiovascular concepts from German discharge letters using pre-trained language models
by
Kiriakou, Christina
,
Richter-Pechanski, Phillip
,
Schwab, Dominic M
in
Deep learning
,
Original Research
2021
Objective
A vast amount of medical data is still stored in unstructured text documents. We present an automated method of information extraction from German unstructured clinical routine data from the cardiology domain enabling their usage in state-of-the-art data-driven deep learning projects.
Methods
We evaluated pre-trained language models to extract a set of 12 cardiovascular concepts in German discharge letters. We compared three bidirectional encoder representations from transformers pre-trained on different corpora and fine-tuned them on the task of cardiovascular concept extraction using 204 discharge letters manually annotated by cardiologists at the University Hospital Heidelberg. We compared our results with traditional machine learning methods based on a long short-term memory network and a conditional random field.
Results
Our best performing model, based on publicly available German pre-trained bidirectional encoder representations from the transformer model, achieved a token-wise micro-average F1-score of 86% and outperformed the baseline by at least 6%. Moreover, this approach achieved the best trade-off between precision (positive predictive value) and recall (sensitivity).
Conclusion
Our results show the applicability of state-of-the-art deep learning methods using pre-trained language models for the task of cardiovascular concept extraction using limited training data. This minimizes annotation efforts, which are currently the bottleneck of any application of data-driven deep learning projects in the clinical domain for German and many other European languages.
Journal Article
Invasive hemodynamics and cardiac biomarkers to predict outcomes after percutaneous edge-to-edge mitral valve repair in patients with severe heart failure
by
Pleger, Sven T
,
Greiner, Sebastian
,
Bekeredjian, Raffi
in
Biomarkers
,
Calcium-binding protein
,
Catheterization
2019
BackgroundPercutaneous mitral valve repair (PMVR) via MitraClip implantation is a therapeutic option for high-risk or non-surgical candidates with severe mitral regurgitation (MR) and advanced stages of heart failure (HF). However, these patients have a high mortality despite PMVR, and predictors for outcomes are not well established. Here, we evaluated invasive hemodynamics, echocardiography parameters, and biomarkers to predict outcomes after PMVR in severe HF patients.MethodsPatients with reduced ejection fraction (EF) and severe and moderate-to-severe MR undergoing PMVR at our centre between September 2009 and January 2016 were analysed retrospectively. Inclusion criteria were: left ventricular EF < 45%, preoperative right heart catheterization, successful MitraClip deployment (“technical success”), and follow-up for at least 1 year after the procedure. Data from preoperative right heart catheterization, echocardiography, and biomarkers were assessed. Primary endpoint was all-cause mortality at 1 year after PMVR. We performed univariate and multivariate Cox regression analyses and generated a risk score to predict outcomes.ResultsOf 174 patients with PMVR and severe HF, 79.9% had functional MR. Mean EF was 25% (17.2; 30.7) and advanced New York Heart Association functional class was prevalent (class II: 13%; class III: 70%; and class IV: 17%). The cumulative incidences of all-cause death were 6.9% and 17.8% at 30 days and 1 year, respectively. In the Cox multivariate model, high-sensitive troponin T [hsTnT; hazard ratio (HR) 1.01; confidence interval (CI) 1.01–1.02; p < 0.0001] and mixed venous O2-saturation (HR 0.92; CI 0.89–0.96; p < 0.0001) were found to significantly and independently predict outcomes. A simple risk score including these two parameters was sufficient to discriminate between low- and high-risk patients (HR 7.22; CI 3.4–15.5; p < 0.001).ConclusionIn a cohort of patients with severe HF undergoing PMVR, patients with elevated hsTnT and reduced mixed venous O2-saturation carried the worst prognosis. A simple risk score including these two parameters may improve patient selection and outcomes after PMVR.
Journal Article
Impact of Percutaneous Mitral Valve Repair Using the MitraClipTM System on Ventricular Arrhythmias and ICD Therapies
by
Schlegel, Philipp
,
Täger, Tobias
,
Kreusser, Michael M.
in
Arrhythmia
,
Cardiac arrhythmia
,
Ejection fraction
2022
Transcatheter edge-to-edge repair (TEER) using the MitraClip™ device has been established as a suitable alternative to mitral valve surgery in patients with severe mitral regurgitation (MR) and high or prohibitive surgical risk. Only limited information regarding the impact of TEER on ventricular arrhythmias (VA) has been reported. The aim of the present study was to assess the impact of TEER using the MitraClipTM device on the burden of VA and ICD (Implantable Cardioverter Defibrillator) therapies. Among 600 MitraClipTM implantations performed in our clinic between September 2009 and October 2018, we identified 86 patients with successful TEER and an active implantable cardiac device (pacemaker, ICD, CRT-P/D (Cardiac Resynchronization Therapy-Pacemaker/Defibrillator)) eligible for retrospective VA analyses. These patients presented with mainly functional MR (81.4%) and severely reduced left ventricular ejection fraction (mean LVEF 22.1% ± 10.3%). The observation period comprised 456 ± 313 days before and 424 ± 287 days after TEER. The burden of ventricular arrhythmias (sustained ventricular tachycardia (sVT) and ventricular fibrillation (VF)) was significantly reduced after TEER (0.85 ± 3.47 vs. 0.43 ± 2.03 events per patient per month, p = 0.01). Furthermore, the rate of ICD therapies (anti-tachycardia pacing (ATP) and ICD shock) decreased significantly after MitraClipTM implantation (1.0 ± 3.87 vs. 0.32 ± 1.41, p = 0.014). However, reduction of VA burden did not result in improved two-year survival in this patient cohort with severely reduced LVEF. Mitral valve TEER using the MitraClip™ device was associated with a significant reduction of ventricular arrhythmias and ICD therapies.
Journal Article
MitraClip implantation followed by insertion of a left ventricular assist device in patients with advanced heart failure
by
Grossekettler, Leonie
,
Kreusser, Michael M.
,
Volz, Martin J.
in
Advanced heart failure
,
Creatinine
,
Ejection fraction
2020
Aims Mitral valve regurgitation (MR) is common in patients with advanced heart failure (HF). Percutaneous mitral valve repair (PMVR) via MitraClip (MC) has emerged as a feasible treatment strategy for these high‐risk patients. However, as HF often further progresses, there is a frequent need for left ventricular assist device (LVAD) implantation in these patients. We aimed to investigate whether prior MC implantation affects the subsequent LVAD implantation and outcome. Methods and results Thirty‐seven patients with advanced HF and significant MR who underwent LVAD implantation were retrospectively analysed. Follow‐up data were collected at 1 year after LVAD implantation. Primary endpoint was all‐cause mortality. Secondary endpoint included peri‐operative parameters and clinical development depicted as New York Heart Association (NYHA) class and Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) level. Seventeen patients initially received a MC device (MC group), resulting in a significant reduction in MR grade. After MC, NYHA class and INTERMACS level further worsened, leading to subsequent LVAD implantation after a median time of 475 days in the MC group. At LVAD implantation, overall characteristics were comparable with those of the patients undergoing LVAD implantation without prior MC placement (no‐MC group). Procedural data revealed a higher incidence of right ventricular (RV) failure needing mechanical RV assistance and a longer need for nitric oxide ventilation in the MC group after LVAD implantation. One‐year survival was slightly better in the no‐MC group compared with the MC group [41% (n = 7/17) vs. 65% (n = 13/20); P = 0.15], albeit event‐free survival was comparable between both groups, MC and no‐MC. Conclusions LVAD implantation after MC is feasible and safe. However, in patients with advanced HF and severe MR, PMVR may only delay a needed LVAD implantation and thereby lead to poorer peri‐operative RV function and impaired outcome. Arguably, these patients might benefit from the timely management of advanced HF by the means of early LVAD implantation or heart transplantation.
Journal Article
PASCAL‐based mitral valve repair in an all‐comer population: acute and mid‐term clinical results
by
Schlegel, Philipp
,
Crespo López, Patricia
,
Kreusser, Michael M.
in
Cardiac arrhythmia
,
Cardiovascular disease
,
Catheters
2021
Aims We investigated short and mid‐term safety and efficacy of the PASCAL system for percutaneous mitral valve repair (PMVr) in severe mitral regurgitation (MR) in an all‐comer population. Methods and results In the first consecutive 41 patients undergoing PMVr using the PASCAL system in our centre, procedural success and safety were assessed. Efficacy in improving MR and functional class were evaluated. Median patient age was 74 years, 58.5% were male patients, and median European System for Cardiac Operative Risk Evaluation Score II was 5.1%. All patients suffered from severe MR with 59% functional MR, 29% degenerative MR, and 12% of mixed aetiology MR. The technical success rate was 90%, limited by four cases where PASCAL implantation was aborted due to a prohibitive mitral gradient. On average, 1.16 PASCAL devices per patient were implanted. All patients successfully implanted with a PASCAL device were discharged with MR grade ≤ 2 and 79% with MR grade ≤ 1. Mean follow‐up was 8.7 ± 4.9 months. Ninety‐seven per cent of patients remained at MR ≤ 2 at follow‐up, which translated into a significantly improved New York Heart Association functional class as well as a significant reduction of systolic pulmonary artery pressure and brain natriuretic peptide levels. The procedure‐related rate for major adverse events was 3%. Neither early nor late single‐leaflet detachment was found. In one patient, air embolism occurred, resulting in modification of the PASCAL instructions for use. Conclusions Percutaneous mitral valve repair using PASCAL in a real‐world, all‐comer population was feasible and safe, resulting in a significant mid‐term reduction of MR with persistent clinical improvement.
Journal Article
Re‐do MitraClip in patients with functional mitral valve regurgitation and advanced heart failure
by
Grossekettler, Leonie
,
Kreusser, Michael M.
,
Volz, Martin J.
in
Advanced heart failure
,
Cardiomyopathy
,
Dyspnea
2021
Aim Percutaneous mitral valve repair (PMVR) via MitraClip implantation is a therapeutic option for severe mitral regurgitation (MR) in advanced stages of heart failure (HF). However, progressive left ventricular dilation in these patients may lead to recurrent MR after PMVR and consequent re‐do MitraClip implantation. Here, we describe the characteristics and outcomes of this clinical scenario. Methods and results Patients with systolic HF and functional MR undergoing a re‐do MitraClip procedure were retrospectively analysed. Inclusion criteria were age ≥18 years, technical, device and procedural success at first MitraClip procedure, functional MR and systolic HF with an ejection fraction (EF) of <45%. Seventeen out of 684 patients undergoing PMVR with the MitraClip device at our institution between September 2009 and July 2019 were included. All patients displayed advanced HF with an EF of 20% (±9.9) and highly elevated N‐terminal pro‐brain natriuretic peptide. Technical success of the re‐do MitraClip procedure was 100%, whereas procedural and device success were only achieved in 11 patients (65%). Unsuccessful re‐do procedures were related to lower EF and implantation of more than one clip at initial procedure. However, despite reduction in MR grade and no occurrence of significant mitral stenosis after the procedure, the mortality during 12 months follow‐up remained high (8 of 17; 47%). Conclusions In a cohort of patients with advanced HF undergoing PMVR, re‐do MitraClip procedure was feasible, but procedural success was unsatisfactory and morbidity and mortality remained high, possibly reflecting the advanced stage of HF in these patients.
Journal Article