Trends in clinical trials for stroke by cell therapy: data mining ClinicalTrials.gov and the ICTRP portal site

Stem cell therapy: a new hope for stroke and traumatic brain injury recovery and the challenge for rural minorities in South Carolina

Stroke and traumatic brain injury (TBI) are a significant cause of death and disability nationwide. Both are considered public health concerns in rural communities in the state of South Carolina (SC), particularly affecting the African American population resulting in considerable morbidity, mortality, and economic burden. Stem cell therapy (SCT) has emerged as a potential intervention for both diseases with increasing research trials showing promising results. In this perspective article, the authors aim to discuss the current research in the field of SCT, the results of early phase trials, and the utilization of outcome measures and biomarkers of recovery. We searched PubMed from inception to December 2023 for articles on stem cell therapy in stroke and traumatic brain injury and its impact on rural communities, particularly in SC. Early phase trials of SCT in Stroke and Traumatic Brain injury yield promising safety profile and efficacy results, but the findings have not yet been consistently replicated. Early trials using mesenchymal stem cells for stroke survivors showed safety, feasibility, and improved functional outcomes using broad and domain-specific outcome measures. Neuroimaging markers of recovery such as Functional Magnetic Resonance Imaging (fMRI) and electroencephalography (EEG) combined with neuromodulation, although not widely used in SCT research, could represent a breakthrough when evaluating brain injury and its functional consequences. This article highlights the role of SCT as a promising intervention while addressing the underlying social determinants of health that affect therapeutic outcomes in relation to rural communities such as SC. It also addresses the challenges ethical concerns of stem cell sourcing, the high cost of autologous cell therapies, and the technical difficulties in ensuring transplanted cell survival and strategies to overcome barriers to clinical trial enrollment such as the ethical concerns of stem cell sourcing, the high cost of autologous cell therapies, and the technical difficulties in ensuring transplanted cell survival and equitable healthcare.

Depression clinical trials worldwide: a systematic analysis of the ICTRP and comparison with ClinicalTrials.gov

Major depressive disorder (MDD), commonly known as depression, affects over 300 million people worldwide as of 2018 and presents a wide range of clinical symptoms. The international clinical trials registry platform (ICTRP) introduced by WHO includes aggregated data from ClinicalTrials.gov and 17 other national registers, making it the largest clinical trial platform. Here we analysed data in ICTRP with the aim of providing comprehensive insights into clinical trials on depression. Applying a novel hidden duplicate identification method, 10,606 depression trials were identified in ICTRP, with ANZCTR being the largest non- ClinicalTrials.gov database at 1031 trials, followed by IRCT with 576 trials, ISRCTN with 501 trials, CHiCTR with 489 trials, and EUCTR with 351 trials. The top four most studied drugs, ketamine, sertraline, duloxetine, and fluoxetine, were consistent in both groups, but ClinicalTrials.gov had more trials for each drug compared to the non-ClinicalTrials.gov group. Out of 9229 interventional trials, 663 unique agents were identified, including approved drugs (74.5%), investigational drugs (23.2%), withdrawn drugs (1.8%), nutraceuticals (0.3%), and illicit substances (0.2%). Both ClinicalTrials.gov and non-ClinicalTrials.gov databases revealed that the largest categories were antidepressive agents (1172 in ClinicalTrials.gov and 659 in non-ClinicalTrials.gov) and nutrients, amino acids, and chemical elements (250 in ClinicalTrials.gov and 659 in non-ClinicalTrials.gov), indicating a focus on alternative treatments involving dietary supplements and nutrients. Additionally, 26 investigational antidepressive agents targeting 16 different drug targets were identified, with buprenorphine (opioid agonist), saredutant (NK2 antagonist), and seltorexant (OX2 antagonist) being the most frequently studied. This analysis addresses 40 approved drugs for depression treatment including new drug classes like GABA modulators and NMDA antagonists that are offering new prospects for treating MDD, including drug-resistant depression and postpartum depression subtypes.

Stem Cell Therapy for Repair of the Injured Brain: Five Principles

Cell therapy holds great promise for regenerative treatment of disease. Despite recent breakthroughs in clinical research, applications of cell therapies to the injured brain have not yielded the desired results. We pinpoint current limitations and suggest five principles to advance stem cell therapies for brain regeneration. While we focus on cell therapy for stroke, all principles also apply for other brain diseases.

Stem cell-based interventions for the treatment of stroke in newborn infants

BACKGROUND

Perinatal stroke refers to a diverse but specific group of cerebrovascular diseases that occur between 20 weeks of fetal life and 28 days of postnatal life. Acute treatment options for perinatal stroke are limited supportive care, such as controlling hypoglycemia and seizures. Stem cell-based therapies offer a potential therapeutic approach to repair, restore, or regenerate injured brain tissue. Preclinical findings have culminated in ongoing human neonatal studies.

OBJECTIVES

To evaluate the benefits and harms of stem cell-based interventions for the treatment of stroke in newborn infants compared to control (placebo or no treatment) or stem-cell based interventions of a different type or source.

SEARCH METHODS

We searched CENTRAL, PubMed, Embase, and three trials registries in February 2023. We planned to search the reference lists of included studies and relevant systematic reviews for studies not identified by the database searches.

SELECTION CRITERIA

We attempted to include randomized controlled trials, quasi-randomized controlled trials, and cluster trials that evaluated any of the following comparisons. • Stem cell-based interventions (any type) versus control (placebo or no treatment) • Mesenchymal stem/stromal cells (MSCs) of a specifictype (e.g. number of doses or passages) or source (e.g. autologous/allogeneic or bone marrow/cord) versus MSCs of another type or source • Stem cell-based interventions (other than MSCs) of a specific type (e.g. mononuclear cells, oligodendrocyte progenitor cells, neural stem cells, hematopoietic stem cells, or induced pluripotent stem cell-derived cells) or source (e.g. autologous/allogeneic or bone marrow/cord) versus stem cell-based interventions (other than MSCs) of another type or source • MSCs versus stem cell-based interventions other than MSCs We planned to include all types of transplantation regardless of cell source (bone marrow, cord blood, Wharton's jelly, placenta, adipose tissue, peripheral blood), type of graft (autologous or allogeneic), and dose.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were all-cause neonatal mortality, major neurodevelopmental disability, and immune rejection or any serious adverse event. Our secondary outcomes included all-cause mortality prior to first hospital discharge, seizures, adverse effects, and death or major neurodevelopmental disability at 18 to 24 months of age. We planned to use GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

We identified no completed or ongoing randomized trials that met our inclusion criteria. We excluded three studies: two were phase 1 trials, and one included newborn infants with conditions other than stroke (i.e. cerebral ischemia and anemia). Among the three excluded studies, we identified the first phase 1 trial on the use of stem cells for neonatal stroke. It reported that a single intranasal application of bone marrow-derived MSCs in term neonates with a diagnosis of perinatal arterial ischemic stroke (PAIS) was feasible and apparently not associated with severe adverse events. However, the trial included only 10 infants, and follow-up was limited to three months.

AUTHORS' CONCLUSIONS

No evidence is currently available to evaluate the benefits and harms of stem cell-based interventions for treatment of stroke in newborn infants. We identified no ongoing studies. Future clinical trials should focus on standardizing the timing and method of cell delivery and cell processing to optimize the therapeutic potential of stem cell-based interventions and safety profiles. Phase 1 and large animal studies might provide the groundwork for future randomized trials. Outcome measures should include all-cause mortality, major neurodevelopmental disability and immune rejection, and any other serious adverse events.

Bone marrow-derived mononuclear cells ameliorate neurological function in chronic cerebral infarction model mice via improvement of cerebral blood flow

BACKGROUND AIMS

Stroke is a frequently observed neurological disorder that might lead to permanent and severe disability. Recently, various regenerative therapies have been developed, some of which have already been applied clinically. However, their outcomes have not been fully satisfactory. In particular, the development of regenerative therapies for chronic ischemic stroke is greatly needed. Herein intracerebral administration of bone marrow-derived mononuclear cells (BM-MNCs) was assessed as a potential treatment for chronic ischemic stroke using a severe combined immunodeficiency mouse model characterized by minimal vascular variation unrelated to immunodeficiency.

METHODS

A reproducible model of permanent middle cerebral artery occlusion was prepared, and intracerebral BM-MNC transplantation was performed 14 days after stroke induction in the infarcted brain.

RESULTS

Sensorimotor behavioral function and cerebral blood flow were significantly improved upon treatment with BM-MNCs compared to control medium injection. The transplanted cells exhibited characteristics of the vascular endothelium and microglia/macrophages. Significant angiogenesis and suppression of astrogliosis and microgliosis were observed in the affected brain. Messenger RNA expression analysis showed significant increases in anti-inflammatory cytokines, A2 astrocyte/anti-inflammatory microglia markers and vascular endothelial markers such as vascular endothelial growth factor and significant decreases in pro-inflammatory cytokines and A1 astrocyte/pro-inflammatory microglia markers following BM-MNC transplantation.

CONCLUSIONS

These results suggest that intracerebral administration of BM-MNCs should be considered an effective cell therapy for chronic stroke.

The international clinical trials registry platform (ICTRP): data integrity and the trends in clinical trials, diseases, and drugs

Introduction: Clinical trials are the gold standard for testing new therapies. Databases like ClinicalTrials.gov provide access to trial information, mainly covering the US and Europe. In 2006, WHO introduced the global ICTRP, aggregating data from ClinicalTrials.gov and 17 other national registers, making it the largest clinical trial platform by June 2019. This study conducts a comprehensive global analysis of the ICTRP database and provides framework for large-scale data analysis, data preparation, curation, and filtering. Materials and methods: The trends in 689,793 records from the ICTRP database (covering trials registered from 1990 to 2020) were analyzed. Records were adjusted for duplicates and mapping of agents to drug classes was performed. Several databases, including DrugBank, MESH, and the NIH Drug Information Portal were used to investigate trends in agent classes. Results: Our novel approach unveiled that 0.5% of the trials we identified were hidden duplicates, primarily originating from the EUCTR database, which accounted for 82.9% of these duplicates. However, the overall number of hidden duplicates within the ICTRP seems to be decreasing. In total, 689 793 trials (478 345 interventional) were registered in the ICTRP between 1990 and 2020, surpassing the count of trials in ClinicalTrials.gov (362 500 trials by the end of 2020). We identified 4 865 unique agents in trials with DrugBank, whereas 2 633 agents were identified with NIH Drug Information Portal data. After the ClinicalTrials.gov, EUCTR had the most trials in the ICTRP, followed by CTRI, IRCT, CHiCTR, and ISRCTN. CHiCTR displayed a significant surge in trial registration around 2015, while CTRI experienced rapid growth starting in 2016. Conclusion: This study highlights both the strengths and weaknesses of using the ICTRP as a data source for analyzing trends in clinical trials, and emphasizes the value of utilizing multiple registries for a comprehensive analysis.

A Pilot Study on Result Reporting Rates from Clinical Trials of Regenerative Medicine

Sharing the methods and results of clinical trials with full transparency is an ethical obligation for those involved in clinical research. In this regard, ClinicalTrials.gov requires reporting of results to the registry within 1 year of completion of the trial. However, a poor result reporting rate has been pointed out, with approximately half the trial results not been reported. It has been suggested that one of the reasons behind this could be the influence of sponsors who conduct the clinical trials. In the course of our previous trend analysis on regenerative medicine for stroke (STR) using ClinicalTrials.gov and the International Clinical Trials Registry Platform (ICTRP) portal site as data sources, we suspected whether the results of gene and/or cell therapy trials are poorly reported. For this reason, a multivariate analysis using data from ClinicalTrials.gov was performed to identify the factors suppressing the result reporting rate, expanding our study to four different kinds of neurological diseases and regenerative medicine as a treatment modality when small-molecule compounds and biologics were set up as controls, in addition to the sponsor type factor. As a result, we found gene and/or cell therapy (therapeutic modality) in addition to STR (disease area), trials completed in 2005-2007, and clinical phases II and IV as independent factors that suppressed the rate of reporting results to ClinicalTrials.gov. On the other hand, big pharmaceutical companies were identified as a factor that increased the reporting result rate to ClinicalTrials.gov. When we applied result reporting publications through PubMed as an index, our study data revealed that the following factors were not identified as the cause for a decrease in the reporting result rate: STR (as disease area), trials completed between 2005 and 2007, and gene/cell therapy (as treatment modality). In this context, our findings indicate that gene/cell therapy has led to the suppression of the result reporting rate to ClinicalTrials.gov. This confirmed our initial suspicion of the low result reporting rate of gene/cell therapy trials. We believe that further studies are required to elucidate the factors affecting the result reporting rate from the perspective of disease area and treatment modality. Impact Statement Several studies have addressed the poor result reporting rate of clinical trials, which still remains an issue. Regenerative medicine holds great promise for the future and the process of its practical application is expected to be challenging. Although having a limited disease area and small sample size, to the best of our knowledge, this is the first study to point out insufficient result reporting of clinical trials of regenerative medicine from the perspective of treatment modality. This report highlights an issue for discussing the path toward its translation through an overview of various factors in comparison with conventional treatment modalities.

Clinical trials of stem cell-based therapies for pediatric diseases: a comprehensive analysis of trials registered on ClinicalTrials.gov and the ICTRP portal site

BACKGROUND

Research on clinical trials that employ stem cells to treat children's diseases is limited. The clinical trial registry database provides a unique window to us to get known about clinical trial researches with different statuses. However, few studies aimed to perform a comprehensive and thorough analysis of those registered trials in the aforementioned field based on ClinicalTrials.gov and the ICTRP portal site.

METHODS

Our study covered the clinical researches about stem cell therapy enrolling subjects aged under 18 years old registered on ClinicalTrials.gov and WHO ICTRP before May 18, 2021. A cross-sectional study was implemented to comprehensively describe and analyze the included trials that met the criteria. Results were available on ClinicalTrials.gov, and publications related to the included trials were identified. All analyses were performed utilizing the SPSS 25.0 software.

RESULTS

Eventually, 202 clinical trials were included and evaluated. The participant number of trials tended to be small; 71.3% were enrolled < 50. And 93.5% of the subjects were without gender restrictions. Till May 2020, 112 trials had been preliminary completed, of which only 39 trials had published papers or uploaded results. Most (73.6%) of 186 interventional trials were in phase 1 and phase 2, where 131 (70.4%) trials were conducted without masking, and 26.3% trials were randomized; 55.4% trials were performed single group assignment. Of 16 observational trials, case-only/series took up 37.5%. Hematopoietic stem cells (37.1%) and mesenchymal stem cells (36.1%) were mostly employed, while umbilical cord blood (UCB)-derived cells (24.3%) and bone marrow (BM)-derived cells (20.8%) were the major sources.

CONCLUSIONS

This study provided an overall picture of utilizing stem cells for treatment and management of childhood diseases. Since clinical trials in this area are insufficient in quantity and quality, there is an urgent need of larger, better-designed trials. Increased investment in clinical research of stem cell treatment products should be carried out to achieve the transformation of results as soon as possible. Moreover, it is important to optimize the management of the registration platform and shorten the time it takes for research results to be published.

Present and future avenues of cell-based therapy for brain injury: The enteric nervous system as a potential cell source

Cell therapy is a promising strategy in the field of regenerative medicine; however, several concerns limit the effective clinical use, namely a valid cell source. The gastrointestinal tract, which contains a highly organized network of nerves called the enteric nervous system (ENS), is a valuable reservoir of nerve cells. Together with neurons and neuronal precursor cells, it contains glial cells with a well described neurotrophic potential and a newly identified neurogenic one. Recently, enteric glia is looked at as a candidate for cell therapy in intestinal neuropathies. Here, we present the therapeutic potential of the ENS as cell source for brain repair, too. The example of stroke is introduced as a brain injury where cell therapy appears promising. This disease is the first cause of handicap in adults. The therapies developed in recent years allow a partial response to the consequences of the disease. The only prospect of recovery in the chronic phase is currently based on rehabilitation. The urgency to offer other treatments is therefore tangible. In the first part of the review, some elements of stroke pathophysiology are presented. An update on the available therapeutic strategies is provided, focusing on cell‐ and biomaterial‐based approaches. Following, the ENS is presented with its anatomical and functional characteristics, focusing on glial cells. The properties of these cells are depicted, with particular attention to their neurotrophic and, recently identified, neurogenic properties. Finally, preliminary data on a possible therapeutic approach combining ENS‐derived cells and a biomaterial are presented.

The Beneficial Potential of Genetically Modified Stem Cells in the Treatment of Stroke: a Review

The last two decades have witnessed a surge in investigations proposing stem cells as a promising strategy to treat stroke. Since growth factor release is considered as one of the most important aspects of cell-based therapy, stem cells over-expressing growth factors are hypothesized to yield higher levels of therapeutic efficiency. In pre-clinical studies of the last 15 years that were investigating the efficiency of stem cell therapy for stroke, a variety of stem cell types were genetically modified to over-express various factors. In this review we summarize the current knowledge on the therapeutic efficiency of stem cell-derived growth factors, encompassing techniques employed and time points to evaluate. In addition, we discuss several types of stem cells, including the recently developed model of epidermal neural crest stem cells, and genetically modified stem cells over-expressing specific factors, which could elevate the restorative potential of naive stem cells. The restorative potential is based on enhanced survival/differentiation potential of transplanted cells, apoptosis inhibition, infarct volume reduction, neovascularization or functional improvement. Since the majority of studies have focused on the short-term curative effects of genetically engineered stem cells, we emphasize the need to address their long-term impact.

Mesenchymal Stem Cells for Neurological Disorders

Neurological disorders are becoming a growing burden as society ages, and there is a compelling need to address this spiraling problem. Stem cell-based regenerative medicine is becoming an increasingly attractive approach to designing therapies for such disorders. The unique characteristics of mesenchymal stem cells (MSCs) make them among the most sought after cell sources. Researchers have extensively studied the modulatory properties of MSCs and their engineering, labeling, and delivery methods to the brain. The first part of this review provides an overview of studies on the application of MSCs to various neurological diseases, including stroke, traumatic brain injury, spinal cord injury, multiple sclerosis, amyotrophic lateral sclerosis, Alzheimer's disease, Huntington's disease, Parkinson's disease, and other less frequently studied clinical entities. In the second part, stem cell delivery to the brain is focused. This fundamental but still understudied problem needs to be overcome to apply stem cells to brain diseases successfully. Here the value of cell engineering is also emphasized to facilitate MSC diapedesis, migration, and homing to brain areas affected by the disease to implement precision medicine paradigms into stem cell-based therapies.

Automated Identification of Common Disease-Specific Outcomes for Comparative Effectiveness Research Using ClinicalTrials.gov: Algorithm Development and Validation Study

Background

Common disease-specific outcomes are vital for ensuring comparability of clinical trial data and enabling meta analyses and interstudy comparisons. Traditionally, the process of deciding which outcomes should be recommended as common for a particular disease relied on assembling and surveying panels of subject-matter experts. This is usually a time-consuming and laborious process.

Objective

The objectives of this work were to develop and evaluate a generalized pipeline that can automatically identify common outcomes specific to any given disease by finding, downloading, and analyzing data of previous clinical trials relevant to that disease.

Methods

An automated pipeline to interface with ClinicalTrials.gov’s application programming interface and download the relevant trials for the input condition was designed. The primary and secondary outcomes of those trials were parsed and grouped based on text similarity and ranked based on frequency. The quality and usefulness of the pipeline’s output were assessed by comparing the top outcomes identified by it for chronic obstructive pulmonary disease (COPD) to a list of 80 outcomes manually abstracted from the most frequently cited and comprehensive reviews delineating clinical outcomes for COPD.

Results

The common disease-specific outcome pipeline successfully downloaded and processed 3876 studies related to COPD. Manual verification indicated that the pipeline was downloading and processing the same number of trials as were obtained from the self-service ClinicalTrials.gov portal. Evaluating the automatically identified outcomes against the manually abstracted ones showed that the pipeline achieved a recall of 92% and precision of 79%. The precision number indicated that the pipeline was identifying many outcomes that were not covered in the literature reviews. Assessment of those outcomes indicated that they are relevant to COPD and could be considered in future research.

Conclusions

An automated evidence-based pipeline can identify common clinical trial outcomes of comparable breadth and quality as the outcomes identified in comprehensive literature reviews. Moreover, such an approach can highlight relevant outcomes for further consideration.

Bidirectional Enhancement of Cell Proliferation Between Iron Oxide Nanoparticle-Labeled Mesenchymal Stem Cells and Choroid Plexus in a Cell-Based Therapy Model of Ischemic Stroke

PURPOSE

Stem cell therapy for ischemic stroke has shown success in experimental settings, but its translation into clinical practice is challenging. The choroid plexus (CP) plays a regulatory role in neural regeneration. Mesenchymal stem cells (MSCs) promote neurogenesis in the ventricular-subventricular zone. However, it is unclear whether MSCs interact with the CP in brain tissue repair.

METHODS

Rat (r)MSCs were labeled with iron oxide nanoparticles (IONs) and transduced with red fluorescent protein, and then injected into the brain of rats with ischemic stroke and monitored over time by magnetic resonance imaging. The functional recovery of rats was determined by the corner test score, Modified Neurological Severity score, and stroke volume. MSCs and CP were also co-cultured for 14 days, and the medium was analyzed with a cytokine array.

RESULTS

In vivo imaging and histologic analysis revealed that ION-labeled MSCs were mainly located at the injection site and migrated to the infarct area and to the CP. Functional recovery was greater in rats treated with MSCs as compared to those that received mock treatment. Bidirectional enhancement of proliferation in MSCs and CP was observed in the co-culture; moreover, MSCs migrated to the CP. Cytokine analysis revealed elevated levels of proliferation- and adhesion-related cytokines and chemokines in the culture medium. Wikipathway predictions indicated that insulin-like growth factor 1/Akt signaling (WP3675), chemokine signaling pathway (WP2292), and spinal cord injury (WP2432) are involved in the increased proliferation and migration of MSCs co-cultured with the CP.

CONCLUSION

Crosstalk with the CP enhances MSC proliferation and migration in a transwell assay. Moreover, MRI reveals MSC migration towards the CP in an ischemic stroke model. The secreted factors resulting from this interaction have therapeutic potential for promoting functional recovery in the brain after ischemic stroke.

Global trends in clinical trials involving pluripotent stem cells: a systematic multi-database analysis

Pluripotent stem cells (PSCs) hold great potential for novel therapeutic approaches to regenerate or replace functionally impaired tissues. Since the introduction of the induced pluripotent stem cell technology in 2006, the number of scientific publications on this topic has constantly been increasing. However, so far no therapy based on PSCs has found its way into routine clinical use. In this study, we examined research trends related to clinical trials involving PSCs based on data obtained from ClinicalTrials.gov, the ICTRP database from the World Health Organization, as well as from a search of all individual databases that are included in the ICTRP using a multistep search algorithm. Following a stringent inclusion/exclusion procedure 131 studies remained that could be classified as clinical trials involving PSCs. The magnitude of these studies (77.1%) was observational, which implies that no cells were transplanted into patients, and only a minority of studies (22.9%) were of an interventional study type. The number of clinical trials involving induced pluripotent stem cells (iPSCs, 74.8%) was substantially higher than the one involving embryonic stem cells (ESCs, 25.2%). However, the picture changes completely when focusing on interventional studies, where in the majority (73.3%) of cases ESCs were used. Interestingly, also the study duration was significantly shorter for interventional versus observational trials (p = 0.002). When focusing on the geographical study regions, it became obvious that the greatest part of all observational trials was performed in the USA (41.6%) and in France (16.8%), while the magnitude of interventional studies was performed in Asian countries (China 36.7%, Japan 13.3%, South Korea 10.0%) and in the field of ophthalmology. In summary, these results indicate that only a limited number of trials were focusing on the actual transplantation of PSCs into patients in a rather narrow field of diagnoses. The future will tell us, if the iPSC technology will ultimately overcome the current challenges and will finally make its way into routine clinical use.