Technische Universität Dresden: Qucosa
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Simulation of Tetrahedral Profiled Carbon Rovings for Concrete Reinforcements
No full textTextile reinforcements are increasingly establishing their position in the construction industry due to their high tensile properties and corrosion resistance for concrete applications. In contrast to ribbed monolithic steel bars with a defined form-fit effect, the conventional carbon rovings’ bond force is transmitted primarily by an adhesive bond (material fit) between the textile surface and the surrounding concrete matrix. As a result, relatively large bonding lengths are required to transmit bond forces, resulting in inefficient material utilization. Novel solutions such as tetrahedral profiled rovings promise significant improvements in the bonding behavior of textile reinforcements by creating an additional mechanical interlock with the concrete matrix while maintaining the high tensile properties of carbon fibers. Therefore, simulative investigations of tensile and bond behavior have been conducted to increase the transmittable bond force and bond stiffness of profiled rovings through a defined roving geometry. Geometric and material models were thus hereby developed, and tensile and pullout tests were simulated. The results of the simulations and characterizations could enable the optimization of the geometric parameters of tetrahedral profiled rovings to achieve better bond and tensile properties and provide basic principles for the simulative modeling of profiled textile reinforcements
Red-Light-Selective Organic Photodiodes via Optical and Material Tuning for Implantable Sensors
No full textNarrowband organic photodiodes (OPDs) are highly attractive for biomedical imaging due to their flexibility, biocompatibility, and compact form. Unlike their inorganic counterparts, OPDs can achieve spectral selectivity through the choice of material and device architecture. This is especially important in fluorescence imaging, where detecting faint signals while blocking out intense excitation light is critical. In this study, we investigated different strategies to achieve red-light-selective OPDs. First, we used an intrinsically narrowband organic absorber material able to absorb red light at relatively low FWHM. Next, we investigated OPDs with charge collection narrowing and a self-filtering approach, both of which demonstrated a strong bichromatic responsivity ratio for red to green light of approximately 125:1 and 20:1, respectively. Subsequently, we incorporated an external absorption filter that blocks blue and green light effectively while allowing red light to transmit onto a broadband-absorbing OPD. The last strategy enabled excellent narrowband red-light detection with a responsivity ratio of up to 66,000:1 for red to green light. The results are promising for future implementation in fluorescence imaging sensors
The regulation of medical devices in developing EU frameworks
No full textBackground
The regulation of medical devices plays an important role in ensuring patient safety and promoting innovation in healthcare. Medical devices include a variety of technologies, applications, and products, ranging from simple everyday items like bandages and thermometers to sophisticated systems such as pacemakers and computed tomography scanners. Digital medical products, including software, artificial intelligence (AI), and mobile health applications, which have increasingly entered the market in recent years, are also often considered medical devices, depending on the intended purpose defined by the manufacturer. If a product is designed for medical purposes, such as diagnosing, treating, or monitoring diseases, it is considered a medical device under many regulatory frameworks worldwide.
In the European Union (EU), medical devices are regulated under Regulation (EU) 2017/745 on medical devices, commonly referred to as the Medical Device Regulation (MDR). The MDR was adopted in 2017 and entered into force in the early 2020s. It was introduced as a response to prior safety scandals involving defective medical devices to enhance patient safety, improve market surveillance, and increase transparency. Unlike pharmaceuticals, which require centralized approval in the EU, medical devices undergo a decentralized conformity assessment process that relies on independent Notified Bodies to certify compliance. The MDR categorizes medical devices into four risk classes, with regulatory requirements increasing according to the level of risk.
Despite the intended improvements, the MDR has introduced new challenges, particularly in the context of innovative technologies. While providing a structured regulatory pathway for traditional hardware-based devices, its suitability for innovative and often digital technologies such as medical extended reality (MXR), gamification in health applications, cybersecurity, and generative AI remains uncertain. These technologies introduce new risks and complexities that were not fully anticipated when the MDR was drafted. Gaps in the current regulatory framework have raised concerns about barriers to innovation, increased costs for manufacturers, and potential delays in market access for new medical devices. Addressing these regulatory challenges is essential to ensure that the European medical device ecosystem remains competitive while maintaining high standards of safety and efficacy.
Research Question/Hypothesis
Technological progress in the healthcare sector and the risks associated with the specific characteristics of these technologies have highlighted the challenges associated with the regulation of these products. This thesis aims to examine these challenges by analyzing how innovative technologies, such as cybersecurity and generative AI, interact with the existing regulatory framework in the EU. This thesis has two main objectives: (1) to identify gaps in the EU regulatory framework that hinder the adoption of innovative medical devices, and (2) to develop recommendations for an improved EU regulatory framework that promotes medical device innovation while ensuring patient safety. By addressing these objectives, this work aims to contribute to the development of a resilient and innovative medical device ecosystem in Europe.
Materials and Methods
To achieve the research objectives of this thesis, innovative technologies that challenge the current EU regulatory framework were identified. The selected technologies, MXR, gamification, cybersecurity, and generative AI, were analyzed using various methodologies to ensure a diverse and comprehensive perspective.
MXR was examined as an example of hardware innovation in medical devices. The analysis focused on how immersive technologies balance technological potential and practical implementation in healthcare. Current guidance documents were examined to assess the regulatory framework and existing solution strategies.
Gamification has been identified as a growing trend in healthcare, particularly in digital health applications. This study examined its regulatory implications by identifying gamified health apps available in app stores and evaluating their compliance with the EU regulatory framework through an expert panel assessment.
Cybersecurity was examined as a significant challenge for medical software and healthcare infrastructure. The research systematically assessed how cybersecurity risks are integrated into the regulatory benefit-risk evaluation of medical devices, highlighting gaps in existing frameworks and the implications for medical device certification.
Generative AI, with a focus on Large Language Models (LLMs), was investigated in two publications. In the first publication, existing LLM-based health applications have been identified, and a subset has been tested and assessed for their compliance with regulatory requirements. The second publication built upon these findings by examining the risks associated with unregulated LLM-based health applications and suggesting recommendations for a future regulatory framework.
Results and Conclusions
The analysis of four innovative medical device technologies showed substantial regulatory gaps and challenges in the current EU framework. However, the implications of these gaps and challenges differ depending on the technology due to their varying regulatory statuses and the necessary adjustments to regulatory systems.
The main challenge for MXR is that there are no clear regulatory guidelines for usability, validation methods, and performance evaluation. Gamification in digital health applications has introduced unique mechanisms for patient engagement that could influence patient behaviour and which are not sufficiently addressed in the current risk management frameworks. Additionally, the regulatory compliance of these applications remains problematic, as many gamified health apps are not adequately certified as medical devices. Cybersecurity was identified as a critical area where regulatory gaps present substantial risks to patient safety. The regulatory framework lacks clear methodologies for incorporating cybersecurity risk into benefit-risk assessments. The publications on generative AI, particularly LLMs, have revealed the most substantial regulatory challenges. These models exhibit unpredictable behaviour, have limited explainability, and introduce new risks that are not compatible with traditional safety assessment methods. Despite their growing importance in healthcare, there is currently no structured approval process for generative AI-based medical applications, which results in unregulated and potentially unsafe products entering the market.
Adapting the existing regulatory framework to address these gaps and challenges involves, among other things, developing specific guidelines for MXR and gamification, defining benefit-risk methodologies for cybersecurity, and establishing a structured regulatory pathway for generative AI. By updating regulations to keep pace with technological advances, the EU can promote a more flexible, efficient, and innovation-friendly regulatory environment that ensures both the safety and accessibility of new medical devices.:Table of Contents – I
List of Tables – III
List of Figures – IV
List of Abbreviations – V
Zusammenfassung – 1
Summary – 5
Introduction – 8
Medical Devices – 8
The Regulation of Medical Devices – 11
The Current Regulatory Framework in the EU – 13
Steps of the Regulatory Process for Medical Devices in the EU – 14
Additional Applicable Regulations for Medical Devices in the EU – 17
Limitations and Challenges of the Current Regulatory Framework in the EU – 21
Regulatory Science – 23
Rational and Research Objectives – 24
Methodology – 25
Publications – 27
Author contributions – 27
Publication 1 - Bridging between hype and implementation in medical extended reality – 29
Publication 2 - The regulatory status of health apps that employ gamification – 33
Publication 3 - Consideration of Cybersecurity in the Benefit-Risk Analysis of Medical Devices: A Scoping Review – 52
Publication 4 - A future role for health applications of large language models depends on regulators enforcing safety standards – 77
Publication 5 - Policing the Boundary Between Responsible and Irresponsible Placing on the Market of LLM Health Applications – 89
Discussion – 101
Primary Results – 101
Gaps and Challenges of the Regulatory Framework – 102
Gaps and Challenges Related to MXR and Gamification – 103
Gaps and Challenges Related to Cybersecurity – 103
Gaps and Challenges Related to AI – 104
Gaps and Challenges Related to Software – 105
Technology-Independent Gaps and Challenges – 105
Consequences for the European Market – 107
Recommendations for an Improved Regulatory Framework – 108
Recommendations Related to MXR and Gamification – 108
Recommendations Related to Cybersecurity – 108
Recommendations Related to AI – 108
Recommendations Related to Software – 109
Recommendations Related to Non-Technical Aspects – 110
Conclusion – 111
References – 113
Acknowledgements – 128
Anlage 1 – 129
Anlage 2 – 13
Development of a risk score to identify patients at high risk for a severe course of COVID‑19
No full textAim: We aimed to develop a risk score to calculate a person’s individual risk for a severe COVID-19 course (POINTED score) to support prioritization of especially vulnerable patients for a (booster) vaccination. - Subject and methods: This cohort study was based on German claims data and included 623,363 individuals with a COVID-19 diagnosis in 2020. The outcome was COVID-19 related treatment in an intensive care unit, mechanical ventilation, or death after a COVID-19 infection. Data were split into a training and a test sample. Poisson regression models with robust standard errors including 35 predefined risk factors were calculated. Coefficients were rescaled with a min–max normalization to derive numeric score values between 0 and 20 for each risk factor. The scores’ discriminatory ability was evaluated by calculating the area under the curve (AUC). - Results: Besides age, down syndrome and hematologic cancer with therapy, immunosuppressive therapy, and other neurological conditions were the risk factors with the highest risk for a severe COVID-19 course. The AUC of the POINTED score was 0.889, indicating very good predictive validity. - Conclusion: The POINTED score is a valid tool to calculate a person’s risk for a severe COVID-19 course
Socioeconomic differences in the utilization of diagnostic imaging and nonpharmaceutical conservative therapies for spinal diseases
No full textBackground:
A different utilization of health care services due to socioeconomic status on the same health plan contradicts the principle of equal treatment. We investigated the presence and magnitude of socioeconomic differences in utilization of diagnostic imaging and non-pharmaceutical conservative therapies for patients with spinal diseases.
Methods:
The cohort study based on routine healthcare data from Germany with 11.7 million patient-years between 2012 and 2016 for patients with physician-confirmed spinal diseases (ICD-10: M40-M54), occupation and age 20 to 64 years. A Poisson model estimated the effects of the socioeconomic status (school education, professional education and occupational position) for the risk ratio of receiving diagnostic imaging (radiography, computed tomography, magnetic resonance imaging) and non-pharmaceutical conservative therapies (physical therapy including exercise therapy, manual therapy and massage, spinal manipulative therapy, acupuncture).
Results:
Patients received diagnostic imaging in 26%, physical therapy in 32%, spinal manipulative therapy in 25%, and acupuncture in 4% of all patient-years. Similar to previous survey-based studies higher rates of utilization were associated with higher socioeconomic status. These differences were most pronounced for manual therapy, exercise therapy, and magnetic resonance imaging.
Conclusions:
The observed differences in health care utilization were highly related to socioeconomic status. Socioeconomic differences were higher for more expensive health services. Further research is necessary to identify barriers to equitable access to health services and to take appropriate action to decrease existing social disparities
Clinical-scale development of universal CAR regulatory T cells guided by insights from polyclonal therapy
No full textAutoimmune diseases and transplant-related allogenic disorders, such as graft-versus-host disease (GvHD), are currently managed using systemic immunosuppressive drugs. However, these systemic therapies are associated with serious risks such as infections and cancer. Therefore, there is a crucial need for more targeted immunosuppressive strategies to improve patient outcomes and quality of life.
The goal of this PhD project was to advance regulatory T cell (Treg) therapy by studying immune responses in patients with steroid-refractory chronic graft-versus-host disease (cGvHD) treated with polyclonal Tregs. Insights gained from this study argued for the development of advanced, antigen-targeted Treg therapies, such as Chimeric Antigen Receptor (CAR)-Treg therapies and led to the establishment of a clinical-scale, GMP-compatible manufacturing process. To further advance the therapy, a universal CAR product was developed to broaden clinical applicability and reduce future development time and cost.
The first part of the project involved monitoring immune responses in cGvHD patients treated with stem cell donor-derived expanded polyclonal Tregs, using longitudinal peripheral blood mononuclear cells (PBMCs) samples collected before and after therapy. To perform high-dimensional immune monitoring, I established and validated a 39-marker mass cytometry (Cytometry by Time of Flight, CyTOF) panel and developed a customized pipeline for longitudinal data analysis. Baseline (pre-therapy) immune analysis revealed major disruptions in immune cell subset distributions, consistent with impaired immune reconstitution, treatment-related depletions and ongoing inflammation. Functional impairments in the patients' endogenous Tregs were evident, accompanied by reduced frequencies. Two out of seven patients showed a partial clinical response with symptom improvement following Treg infusion, while the others predominantly exhibited stable disease throughout the monitored timeframe. Longitudinal analysis showed that circulating Treg levels mainly peaked between one- and four-weeks post-infusion and declined thereafter. Clinical improvements followed the peak of circulating Tregs, but were transient. This highlighted the need for strategies aimed at increasing Treg persistence in vivo to achieve more sustained therapeutic effects. In addition, clinical records indicated that four patients developed infections or cancer following therapy. However, these events were more likely linked to underlying immune deficiencies (such as low frequency of CD4+ T and B cells) in combination with multiple lines treatment rather than directly to Treg infusion. Nonetheless, this emphasized the importance of developing antigen-specific therapies capable of localized immune suppression to minimize systemic risks. Analysis of the infused Treg products showed no clear dose-response relationship with clinical outcomes or in vivo persistence. Instead, I found that Treg products with lower in vitro fold expansion correlated with greater in vivo persistence and improved clinical outcomes. These findings underscore that the quality of the expanded Tregs, rather than their quantity alone, should be considered during manufacturing. Longitudinal immune monitoring revealed that reductions in inflammatory immune subsets (CXCR3+ CD4+ non-Tregs and CXCR3+ CD8+ T cells) occurred as early as 24 hours post-infusion, followed by a decrease in activation marker-expressing subsets (CD38+ and HLA-DR+) that showed a high correlation with clinical response. These immune changes were observed consistently across both responders and patients with stable disease and non-responders. Based on this strong correlation, these immune signatures may be used to monitor and predict therapeutic outcomes in future studies.
Building on these findings, I dedicated the second part of my PhD project to developing a clinical-scale manufacturing protocol for producing antigen-specific Tregs engineered with the Reversed CAR (RevCAR) platform. Instead of a conventional single-chain variable fragment (scFv) for antigen recognition, RevCAR Tregs are engineered to express an inert peptide epitope. Target specificity is conferred through a bispecific reversed target module (RevTM), which simultaneously binds the peptide epitope and the target antigen. These universal adapter RevCAR Tregs can be applied to various disease indications with specific antigen-directing RevTMs to provide localized immunosuppression. As a proof-of-concept, acute GvHD (aGvHD) was selected as the model disease, targeting carcinoembryonic antigen (CEA) highly expressed in the gut. I established a clinical-scale, GMP-compliant manufacturing process integrating GMP-compatible closed-system Treg isolation (MACSQuant Tyto) and closed-system automated gene transfer and expansion (CliniMACS Prodigy).
Across five independent clinical-scale manufacturing runs, isolation of Tregs from healthy donor apheresis material using the designed protocol consistently produced highly pure Treg products. These products could be expanded to reach clinically relevant yields, while maintaining high purity and demonstrating good transduction efficiency. Expanded Tregs preserved a stable regulatory phenotype, characterized by the expression of key co-stimulatory, co-inhibitory and homing markers. Importantly, they maintained FOXP3 and Helios expression even under pro-inflammatory conditions, without producing T effector cytokines such as IL-2 or IL-17A. Functional testing confirmed that RevCAR Tregs were specifically activated in the presence of CEA-expressing target cells. As an exploratory method, I used atomic force microscopy-based single-cell force spectroscopy to measure adhesion forces between RevCAR Tregs and target cells. This technique showed promising potential to quantify specific CAR-antigen adhesion forces important for mechanotransduction, efficient recruitment and retention at target sites. Finally, I demonstrated that RevCAR Tregs retained strong suppressive function and showed dose-dependent suppression of effector T cell proliferation after polyclonal stimulation. Together, these results confirm that the established manufacturing process successfully produces universal RevCAR Tregs with high purity, clinically-relevant yield, efficient transduction and phenotypic stability that can be specifically activated and exert potent suppressive capacity.
In conclusion, this PhD project achieved two major goals. First, immune monitoring after polyclonal Treg therapy provided critical insights into the limitations and opportunities for improving Treg-based therapies, emphasizing the importance of early intervention, antigen-specific targeting, maintenance of Treg persistence and ensuring high product quality. Second, I successfully established a GMP-compatible, clinical-scale process for generating universal RevCAR Tregs. The universal nature supports the advancement of RevCAR Tregs not only for the treatment of aGvHD, but also for a broad range of autoimmune and inflammatory diseases. Moreover, the CyTOF-based immune monitoring pipeline developed in the first part of this project could support future CAR Treg clinical studies through detailed immune profiling to evaluate therapeutic efficacy
Para Badminton: Planungsgrundlagen für eine Mehrzwecksporthalle
No full textIn den letzten Jahren hat sich das Para Badminton auf internationaler Ebene, insbesondere durch die Paralympics 2020 in Tokio, zunehmend im Leistungssport etabliert. In Sachsen ist das Para Badminton im Vereins- und Breitensport nur geringfügig verankert. Für die vermehrte Etablierung des Sports müssen zunächst grundlegende Voraussetzungen geschaffen werden. Ziel dieser Arbeit ist es herauszufinden welche Anforderungen das Para Badminton an die Gestaltung von Mehrzwecksporthallen stellt. [... aus dem Text
Investigation of operating point-dependent, multiaxial friction effects using a combined experimental-analytical approach in the context of virtual load data determination for Battery Electric Vehicle (BEV) elastomeric mounts
No full textVirtual load data determination for mounting systems of electrified powertrains constitutes a significant contribution to reducing development costs in the contemporary automotive industry. In order to improve the predictive accuracy of virtual methods, the transmission behaviour of the mounting components is experimentally investigated within their specific operating range. In particular, the study focuses on the combined deformation and frictional behaviour of the auxiliary stop elements. An existing mount model, originally developed for internal combustion engine (ICE) applications, is adapted to replicate the identified transmission characteristics of battery electric vehicle (BEV) mounts. The model is intended for durability assessment and is primarily used to generate operating load signals via multibody simulation. Model parameterisation is carried out using a particle swarm optimisation algorithm with multiaxial stochastic excitation signals serving as input. The proposed modelling approach has been shown to yield improved predictive accuracy in comparison to conventional standard models. Validation is conducted using measured multiaxial operating load signals with cumulative signal damage and statistical simulation error analysis serving as evaluation metrics. Finally, potential directions for further methodical advancements are outlined
Hierarchical conductive metal-organic framework films enabling efficient interfacial mass transfer
No full textHeterogeneous reactions associated with porous solid films are ubiquitous and play an important role in both nature and industrial processes. However, due to the no-slip boundary condition in pressure-driven flows, the interfacial mass transfer between the porous solid surface and the environment is largely limited to slow molecular diffusion, which severely hinders the enhancement of heterogeneous reaction kinetics. Herein, we report a hierarchical-structure-accelerated interfacial dynamic strategy to improve interfacial gas transfer on hierarchical conductive metal-organic framework (c-MOF) films. Hierarchical c-MOF films are synthesized via the in-situ transformation of insulating MOF film precursors using π-conjugated ligands and comprise both a nanoporous shell and hollow inner voids. The introduction of hollow structures in the c-MOF films enables an increase of gas permeability, thus enhancing the motion velocity of gas molecules toward the c-MOF film surface, which is more than 8.0-fold higher than that of bulk-type film. The c-MOF film-based chemiresistive sensor exhibits a faster response towards ammonia than other reported chemiresistive ammonia sensors at room temperature and a response speed 10 times faster than that of the bulk-type film
Adaptation of a switchable CAR technology for the treatment of glioblastoma
No full textGlioblastoma (GBM) is the most common and aggressive primary brain tumor in adults, with a dismal prognosis and limited treatment options. The current standard of care, involving surgery, radiotherapy, and chemotherapy, often fails to prevent recurrence due to the tumor's invasive nature and immunosuppressive microenvironment. Immunotherapy has emerged as a promising avenue for GBM treatment, aiming to harness the patient's immune system to combat cancer cells. This thesis explores the potential of the UniCAR T cell platform, a switchable chimeric antigen receptor (CAR) technology, to address the challenges of antigen escape and T cell exhaustion in GBM.
The UniCAR platform offers a unique approach to CAR T cell therapy by separating the antigen recognition and T cell activation functions into two distinct components: a universal CAR T cell and a soluble targeting module (TM). This modular design allows for flexible targeting of multiple tumor antigens and precise control over T cell activation, potentially mitigating the risk of antigen escape and T cell exhaustion. The thesis focuses on developing TMs against two tumor-associated antigens (TAAs) commonly overexpressed in GBM: interleukin-13 receptor subunit alpha 2 (IL-13Rα2) and human epidermal growth factor receptor 2 (HER2).
For IL-13Rα2 targeting, the thesis explores two distinct approaches: ligand-based and antibody-based TMs. The ligand-based approach utilizes the natural ligand of IL-13Rα2, interleukin-13 (IL-13), which exhibits high affinity for the receptor. However, IL-13 also interacts with the ubiquitously expressed IL-13Rα1, raising concerns about potential cross-reactivity and off-target effects. To address this, the thesis investigates various IL-13 muteins with amino acid substitutions designed to enhance specificity for IL-13Rα2 while minimizing interaction with IL-13Rα1. TM-IL13mut-V6 was selected as the lead ligand-based TM due to its optimal balance of high potency against IL13Rα2-expressing cells and absence of cross-reactivity with IL13Rα1. Additionally, the thesis explores the fusion of IL-13-based TMs with a silenced IgG1 Fc domain to extend their half-life in plasma, potentially improving therapeutic efficacy and reducing the need for continuous infusions in patients with reduced tumor burden.
The antibody-based approach involves developing novel murine antibodies against IL-13Rα2 and humanizing them to minimize immunogenicity in humans. The thesis describes the generation and characterization of several scFv-based TMs derived from these antibodies, with a focus on optimizing their affinity, potency, and biochemical properties. The lead candidate, TM-IL13Rα2-huV4, demonstrates high affinity and potency against IL-13Rα2-expressing cells, along with favorable stability and reduced immunogenicity risk.
For HER2 targeting, the thesis develops a TM based on the well-established monoclonal antibody trastuzumab, which has shown clinical success in treating HER2-positive breast cancer. The trastuzumab-derived TM exhibits high affinity and potency against HER2-expressing cells, with favorable biochemical and pharmacokinetic properties.
The thesis also investigates the pharmacodynamic properties of the lead TMs, including their internalization kinetics and therapeutic efficacy in vivo. The ligand-based TM-IL13mut-V6 demonstrates faster internalization in glioblastoma cells compared to the scFv-based TMs, potentially contributing to its rapid clearance. In vivo studies in mouse models demonstrate the ability of the TMs to engage UniCAR T cells and mediate tumor cell lysis, confirming their therapeutic potential. However, challenges such as alloreactivity and the need for improved animal models are identified, highlighting areas for further research and development.
In conclusion, this thesis provides a comprehensive exploration of the UniCAR T cell platform for glioblastoma treatment, focusing on the development and characterization of TMs against IL-13Rα2 and HER2. The findings demonstrate the feasibility of targeting these TAAs with UniCAR T cells and highlight the potential of this modular approach to overcome the challenges of antigen escape and T cell exhaustion in GBM. The thesis also identifies areas for further research, including the development of more sophisticated animal models and the optimization of TM design and delivery strategies. Overall, this research contributes to the growing body of knowledge on CAR T cell therapy for solid tumors and offers promising avenues for the development of more effective treatments for glioblastoma.Glioblastom (GBM) ist der häufigste und aggressivste primäre Hirntumor bei Erwachsenen mit einer düsteren Prognose und begrenzten Behandlungsmöglichkeiten. Die derzeitige Standardbehandlung, die chirurgische Entfernung, Strahlentherapie und Chemotherapie umfasst, kann ein Wiederauftreten aufgrund der Invasivität des Tumors und der immunsuppressiven Mikroumgebung oft nicht verhindern. Die Immuntherapie, die das Immunsystem des Patienten zur Bekämpfung von Krebszellen nutzt, hat sich als vielversprechender Weg für die GBM-Behandlung erwiesen. Diese Arbeit untersucht das Potenzial der UniCAR-T-Zellplattform, einer schaltbaren chimären Antigenrezeptor-(CAR)-Technologie, um die Herausforderungen des Antigenverlusts und der T-Zellerschöpfung bei GBM anzugehen.
Die UniCAR-Plattform bietet einen einzigartigen Ansatz für die CAR-T-Zelltherapie, indem sie die Funktionen der Antigenerkennung und der T-Zellaktivierung in zwei verschiedene Komponenten trennt: eine universelle CAR-T-Zelle und ein lösliches Targeting-Modul (TM). Dieses modulare Design ermöglicht eine flexible Ausrichtung auf mehrere Tumorantigene und eine präzise Kontrolle über die T-Zellaktivierung, wodurch möglicherweise das Risiko eines Antigenverlusts und einer T-Zellerschöpfung verringert wird. Die Arbeit konzentriert sich auf die Entwicklung von TMs gegen zwei tumorassoziierte Antigene (TAAs), die bei GBM häufig überexprimiert werden: Interleukin-13-Rezeptor-Untereinheit alpha 2 (IL-13Rα2) und humaner epidermaler Wachstumsfaktor-Rezeptor 2 (HER2).
Für das IL-13Rα2-Targeting untersucht die Arbeit zwei unterschiedliche Ansätze: Liganden-basierte und Antikörper-basierte TMs. Der Liganden-basierte Ansatz nutzt den natürlichen Liganden von IL-13Rα2, Interleukin-13 (IL-13), der eine hohe Affinität für den Rezeptor aufweist. IL-13 interagiert jedoch auch mit dem ubiquitär exprimierten IL-13Rα1, was Bedenken hinsichtlich potenzieller Kreuzreaktivität und Off-Target-Effekten aufwirft. Um dies zu beheben, untersucht die Arbeit verschiedene IL-13-Muteine mit Aminosäuresubstitutionen, die darauf abzielen, die Spezifität für IL-13Rα2 zu erhöhen und gleichzeitig die Wechselwirkung mit IL-13Rα1 zu minimieren. TM-IL13mut-V6 wurde als führendes Liganden-basiertes TM ausgewählt, da es eine optimale Balance zwischen hoher Wirksamkeit gegen IL13Rα2-exprimierende Zellen und fehlender Kreuzreaktivität mit IL13Rα1 bietet. Zusätzlich untersucht die Arbeit die Fusion von IL-13-basierten TMs mit einer stummen IgG1-Fc-Domäne, um ihre Halbwertszeit im Plasma zu verlängern, was möglicherweise die therapeutische Wirksamkeit verbessert und die Notwendigkeit kontinuierlicher Infusionen bei Patienten mit reduzierter Tumorlast verringert.
Der Antikörper-basierte Ansatz beinhaltet die Entwicklung neuartiger muriner Antikörper gegen IL-13Rα2 und deren Humanisierung, um die Immunogenität beim Menschen zu minimieren. Die Arbeit beschreibt die Erzeugung und Charakterisierung mehrerer scFv-basierter TMs, die von diesen Antikörpern abgeleitet sind, mit dem Fokus auf der Optimierung ihrer Affinität, Wirksamkeit und biochemischen Eigenschaften. Der Hauptkandidat, TM-IL13Rα2-huV4, zeigt eine hohe Affinität und Wirksamkeit gegen IL-13Rα2-exprimierende Zellen, zusammen mit einer günstigen Stabilität und einem reduzierten Immunogenitätsrisiko.
Für das HER2-Targeting entwickelt die Arbeit ein TM, das auf dem etablierten monoklonalen Antikörper Trastuzumab basiert, welcher klinische Erfolge bei der Behandlung von HER2-positivem Brustkrebs gezeigt hat. Das von Trastuzumab abgeleitete TM weist eine hohe Affinität und Wirksamkeit gegen HER2-exprimierende Zellen auf, zusammen mit günstigen biochemischen und pharmakokinetischen Eigenschaften.
Die Arbeit untersucht auch die pharmakodynamischen Eigenschaften der führenden TMs, einschließlich ihrer Internalisierungskinetik und therapeutischen Wirksamkeit in vivo. Das Liganden-basierte TM-IL13mut-V6 zeigt eine schnellere Internalisierung in Glioblastomzellen im Vergleich zu den scFv-basierten TMs, was möglicherweise zu seiner schnellen Clearance beiträgt. In-vivo-Studien in Mausmodellen zeigen die Fähigkeit der TMs, UniCAR-T-Zellen zu aktivieren und die Lyse von Tumorzellen zu vermitteln, was ihr therapeutisches Potenzial bestätigt. Herausforderungen wie Alloreaktivität und die Notwendigkeit verbesserter Tiermodelle werden jedoch identifiziert, was Bereiche für weitere Forschung und Entwicklung hervorhebt.
Zusammenfassend bietet diese Arbeit eine umfassende Untersuchung der UniCAR-T-Zellplattform für die Glioblastom-Behandlung, wobei der Schwerpunkt auf der Entwicklung und Charakterisierung von TMs gegen IL-13Rα2 und HER2 liegt. Die Ergebnisse zeigen die Machbarkeit des Targetings dieser TAAs mit UniCAR-T-Zellen und unterstreichen das Potenzial dieses modularen Ansatzes, die Herausforderungen des Antigenverlusts und der T-Zellerschöpfung bei GBM zu überwinden. Die Arbeit identifiziert auch Bereiche für weitere Forschung, einschließlich der Entwicklung anspruchsvollerer Tiermodelle und der Optimierung von TM-Design und Verabreichungsstrategien. Insgesamt trägt diese Forschung zum wachsenden Wissen über die CAR-T-Zelltherapie für solide Tumore bei und bietet vielversprechende Wege für die Entwicklung wirksamerer Behandlungen für Glioblastom