scholarly journals Norovirus: Clinical Findings and Pharmaceutical Developments

2021 ◽  
Author(s):  
Ying-Fei Yang ◽  
Chung-Min Liao
Keyword(s):  
Clinical Trials ◽  
Vaccine Development ◽  
Antiviral Drug ◽  
Point Mutations ◽  
Clinical Findings ◽  
Protection Mechanism ◽  
Healthcare Facilities ◽  
Travel Industry ◽  
High Immunogenicity

Norovirus (NoV) is one of the most ubiquitous factors contributing to acute gastroenteritis that causes widespread outbreaks in travel industry, military, or healthcare facilities. NoV could lead to serious symptoms and result in severe societal costs worldwide. Surprisingly, there has been no available licensed vaccines, albeit there are ongoing pre-clinical or clinical trials of several candidate vaccines. Development of effective universal vaccines has been found difficult clinically due to the frequent point mutations and a lack of robust animal model and cell culture system. Preclinical studies showed that vaccines with virus-like particles (VLPs) have high immunogenicity and efficacies and were demonstrated to be protective and safe. Recent in vitro research also suggests that human intestinal enteroids can enhance our understanding of protection mechanism and give guidance for vaccine development. Overall, this chapter will give a comprehensive review of the current challenge and progress of clinical findings, efficacy/safety of the developing vaccines, and antiviral drug developments for NoV in clinical trials or preclinical investigations.

scholarly journals A comparative analysis of SARS-CoV-2 antivirals characterizes 3CLpro inhibitor PF-00835231 as a potential new treatment for COVID-19

2021 ◽  
Author(s):  
Maren de Vries ◽  
Adil S. Mohamed ◽  
Rachel A. Prescott ◽  
Ana M. Valero-Jimenez ◽  
Ludovic Desvignes ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Life Cycle ◽  
Comparative Analysis ◽  
Airway Epithelium ◽  
Antiviral Drug ◽  
Viral Polymerase ◽  
Direct Acting Antiviral ◽  
Polymerase Inhibitor ◽  
Direct Acting

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the etiological agent of Coronavirus Disease 2019 (COVID-19). There is a dire need for novel effective antivirals to treat COVID-19, as the only approved direct-acting antiviral to date is remdesivir, targeting the viral polymerase complex. A potential alternate target in the viral life cycle is the main SARS-CoV-2 protease 3CLpro (Mpro). The drug candidate PF-00835231 is the active compound of the first anti-3CLpro regimen in clinical trials. Here, we perform a comparative analysis of PF-00835231, the pre-clinical 3CLpro inhibitor GC-376, and the polymerase inhibitor remdesivir, in alveolar basal epithelial cells modified to express ACE2 (A549+ACE2 cells). We find PF-00835231 with at least similar or higher potency than remdesivir or GC-376. A time-of-drug-addition approach delineates the timing of early SARS-CoV-2 life cycle steps in A549+ACE2 cells and validates PF-00835231’s early time of action. In a model of the human polarized airway epithelium, both PF-00835231 and remdesivir potently inhibit SARS-CoV-2 at low micromolar concentrations. Finally, we show that the efflux transporter P-glycoprotein, which was previously suggested to diminish PF-00835231’s efficacy based on experiments in monkey kidney Vero E6 cells, does not negatively impact PF-00835231 efficacy in either A549+ACE2 cells or human polarized airway epithelial cultures. Thus, our study provides in vitro evidence for the potential of PF-00835231 as an effective SARS-CoV-2 antiviral and addresses concerns that emerged based on prior studies in non-human in vitro models. Importance: The arsenal of SARS-CoV-2 specific antiviral drugs is extremely limited. Only one direct-acting antiviral drug is currently approved, the viral polymerase inhibitor remdesivir, and it has limited efficacy. Thus, there is a substantial need to develop additional antiviral compounds with minimal side effects and alternate viral targets. One such alternate target is its main protease, 3CLpro (Mpro), an essential component of the SARS-CoV-2 life cycle processing the viral polyprotein into the components of the viral polymerase complex. In this study, we characterize a novel antiviral drug, PF-00835231, which is the active component of the first-in-class 3CLpro-targeting regimen in clinical trials. Using 3D in vitro models of the human airway epithelium, we demonstrate the antiviral potential of PF-00835231 for inhibition of SARS-CoV-2.

scholarly journals Missing clinical trial data: the evidence gap in the safety of potential COVID-19 drugs

2020 ◽  
Author(s):  
Florence Rodgers ◽  
Toby Pepperrell ◽  
Sarai Keestra ◽  
Victoria Pilkington
Keyword(s):  
Clinical Trial ◽  
Clinical Trials ◽  
Severe Disease ◽  
Safety Information ◽  
Safety Data ◽  
Clinical Trial Data ◽  
Clinical Findings ◽  
Rapid Review ◽  
Clinical Trial Results

Abstract Background: Several drugs are being repurposed for the treatment of the coronavirus disease 2019 (COVID-19) pandemic based on in vitro or early clinical findings. As these drugs are being used in varied regimens and dosages, it is important to enable synthesis of existing safety data from clinical trials. However, availability of safety information is limited by a lack of timely reporting of clinical trial results on public registries or through academic publication. We aimed to analyse the evidence gap in safety data by quantifying the number of missing clinical trial results for drugs potentially being repurposed for COVID-19 by conducting a rapid review of results posting on ClinicalTrials.gov and in academic publications. Methods: ClinicalTrials.gov was searched for 19 drugs that have been identified as potential treatments for COVID-19. Relevant clinical trials for any prior indication were listed by identifier (NCT number) and checked for results and for timely result reporting (within 395 days of the primary completion date). Additionally, PubMed and Google Scholar were searched to identify publications of results not listed on the registry. A second, blinded search of 10% of trials was conducted to assess reviewer concordance. Results: Of 3754 completed trials, 1516 (40.4%) did not post results on ClinicalTrials.gov or in the academic literature. 1172 (31.2%) completed trials had tabular results on ClinicalTrials.gov. A further 1066 (28.4%) completed trials had results from the literature search, but did not report results on ClinicalTrials.gov. Key drugs missing clinical trial results include hydroxychloroquine (37.0% completed trials unreported), favipiravir (77.8%) and lopinavir (40.5%). Conclusions: There is an important evidence gap for the safety of drugs being repurposed for COVID-19. This uncertainty could cause a large burden of additional morbidity and mortality during the pandemic. We recommend caution in experimental drug use for non-severe disease and urge clinical trial sponsors to report missing results retrospectively.

scholarly journals A nucleobase-binding pocket in a viral RNA-dependent RNA polymerase contributes to elongation complex stability

2019 ◽  
Vol 48 (3) ◽  
pp. 1392-1405 ◽  
Author(s):  
Wei Shi ◽  
Han-Qing Ye ◽  
Cheng-Lin Deng ◽  
Rui Li ◽  
Bo Zhang ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Rna Binding ◽  
Vaccine Development ◽  
Antiviral Drug ◽  
Enterovirus 71 ◽  
Binding Pocket ◽  
Genome Replication ◽  
Elongation Complex ◽  
Rna Dependent Rna Polymerase

Abstract The enterovirus 71 (EV71) 3Dpol is an RNA-dependent RNA polymerase (RdRP) that plays the central role in the viral genome replication, and is an important target in antiviral studies. Here, we report a crystal structure of EV71 3Dpol elongation complex (EC) at 1.8 Å resolution. The structure reveals that the 5′-end guanosine of the downstream RNA template interacts with a fingers domain pocket, with the base sandwiched by H44 and R277 side chains through hydrophobic stacking interactions, and these interactions are still maintained after one in-crystal translocation event induced by nucleotide incorporation, implying that the pocket could regulate the functional properties of the polymerase by interacting with RNA. When mutated, residue R277 showed an impact on virus proliferation in virological studies with residue H44 having a synergistic effect. In vitro biochemical data further suggest that mutations at these two sites affect RNA binding, EC stability, but not polymerase catalytic rate (kcat) and apparent NTP affinity (KM,NTP). We propose that, although rarely captured by crystallography, similar surface pocket interaction with nucleobase may commonly exist in nucleic acid motor enzymes to facilitate their processivity. Potential applications in antiviral drug and vaccine development are also discussed.

scholarly journals Combination Treatment With Remdesivir and Ivermectin Exerts Highly Synergistic and Potent Antiviral Activity Against Murine Coronavirus Infection

2021 ◽  
Vol 11 ◽  
Author(s):  
Yu Ling Tan ◽  
Kevin S. W. Tan ◽  
Justin Jang Hann Chu ◽  
Vincent T. Chow
Keyword(s):  
Clinical Trials ◽  
Hepatitis Virus ◽  
Antiviral Drug ◽  
Viral Rna ◽  
Murine Hepatitis Virus ◽  
Combination Drug ◽  
Live Virus ◽  
Raw264.7 Macrophages

The recent COVID-19 pandemic has highlighted the urgency to develop effective antiviral therapies against the disease. Murine hepatitis virus (MHV) is a coronavirus that infects mice and shares some sequence identity to SARS-CoV-2. Both viruses belong to the Betacoronavirus genus, and MHV thus serves as a useful and safe surrogate model for SARS-CoV-2 infections. Clinical trials have indicated that remdesivir is a potentially promising antiviral drug against COVID-19. Using an in vitro model of MHV infection of RAW264.7 macrophages, the safety and efficacy of monotherapy of remdesivir, chloroquine, ivermectin, and doxycycline were investigated. Of the four drugs tested, remdesivir monotherapy exerted the strongest inhibition of live virus and viral RNA replication of about 2-log10 and 1-log10, respectively (at 6 µM). Ivermectin treatment showed the highest selectivity index. Combination drug therapy was also evaluated using remdesivir (6 µM) together with chloroquine (15 µM), ivermectin (2 µM) or doxycycline (15 µM) – above their IC50 values and at high macrophage cell viability of over 95%. The combination of remdesivir and ivermectin exhibited highly potent synergism by achieving significant reductions of about 7-log10 of live virus and 2.5-log10 of viral RNA in infected macrophages. This combination also resulted in the lowest cytokine levels of IL-6, TNF-α, and leukemia inhibitory factor. The next best synergistic combination was remdesivir with doxycycline, which decreased levels of live virus by ~3-log10 and viral RNA by ~1.5-log10. These results warrant further studies to explore the mechanisms of action of the combination therapy, as well as future in vivo experiments and clinical trials for the treatment of SARS-CoV-2 infection.

scholarly journals Missing clinical trial data: the knowledge gap in the safety of potential COVID-19 drugs

2020 ◽  
Author(s):  
Florence Rodgers ◽  
Toby Pepperrell ◽  
Sarai Keestra ◽  
Victoria Pilkington
Keyword(s):  
Clinical Trial ◽  
Clinical Trials ◽  
Severe Disease ◽  
Safety Information ◽  
Safety Data ◽  
Clinical Trial Data ◽  
Clinical Findings ◽  
Knowledge Gap ◽  
Clinical Trial Results

AbstractObjectivesSeveral drugs are being repurposed for the treatment of the coronavirus disease 2019 (COVID-19) pandemic based on in vitro or early clinical findings. As these drugs are being used in varied regimens and dosages, it is important to enable synthesis of existing safety data from clinical trials. However, availability of safety information is limited by a lack of timely reporting of clinical trial results on public registries or through academic publication. We aimed to analyse the knowledge gap in safety data by quantifying the number of missing clinical trial results for drugs potentially being repurposed for COVID-19.DesignClinicalTrials.gov was searched for 19 drugs that have been identified as potential treatments for COVID-19. Relevant clinical trials for any prior indication were listed by identifier (NCT number) and checked for timely result reporting (within 395 days of the primary completion date). Additionally, PubMed and Google Scholar were searched using the NCT number to identify publications of results not listed on the registry. A second, blinded search of 10% of trials was conducted to assess reviewer concordance.ResultsOf 3754 completed trials, 1516 (40.4%) did not post results on ClinicalTrials.gov or in the academic literature. 1172 (31.2%) completed trials had tabular results on ClinicalTrials.gov. A further 1066 (28.4%) completed trials had results from the literature search, but did not report results on ClinicalTrials.gov. Key drugs missing clinical trial results include hydroxychloroquine (37.0% completed trials unreported), favipiravir (77.8%) and lopinavir (40.5%).ConclusionThere is an important evidence gap for the safety of drugs being repurposed for COVID-19. This uncertainty could cause a large burden of additional morbidity and mortality during the pandemic. We recommend caution in experimental drug use for non-severe disease and urge clinical trial sponsors to report missing results retrospectively.

scholarly journals RNA Vaccines: A Suitable Platform for Tackling Emerging Pandemics?

2020 ◽  
Vol 11 ◽  
Author(s):  
Jonas B. Sandbrink ◽  
Robin J. Shattock
Keyword(s):  
Vaccine Development ◽  
Single Injection ◽  
Low Cost ◽  
Phase 1 ◽  
Manufacturing Costs ◽  
Efficacy Trials ◽  
Delivery Mechanism ◽  
High Immunogenicity ◽  
Rna Vaccine

The COVID-19 pandemic demonstrates the ongoing threat of pandemics caused by novel, previously unrecognized, or mutated pathogens with high transmissibility. Currently, vaccine development is too slow for vaccines to be used in the control of emerging pandemics. RNA-based vaccines might be suitable to meet this challenge. The use of an RNA-based delivery mechanism promises fast vaccine development, clinical approval, and production. The simplicity of in vitro transcription of mRNA suggests potential for fast, scalable, and low-cost manufacture. RNA vaccines are safe in theory and have shown acceptable tolerability in first clinical trials. Immunogenicity of SARS-CoV-2 mRNA vaccines in phase 1 trials looks promising, however induction of cellular immunity needs to be confirmed and optimized. Further optimization of RNA vaccine modification and formulation to this end is needed, which may also enable single injection regimens to be achievable. Self-amplifying RNA vaccines, which show high immunogenicity at low doses, might help to improve potency while keeping manufacturing costs low and speed high. With theoretical properties of RNA vaccines looking promising, their clinical efficacy is the key remaining question with regard to their suitability for tackling emerging pandemics. This question might be answered by ongoing efficacy trials of SARS-CoV-2 mRNA vaccines.

scholarly journals A PBMC-Based System to Assess Human T Cell Responses to Influenza Vaccine Candidates In Vitro

Vaccines ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 181 ◽  
Author(s):  
Gabriela Tapia-Calle ◽  
Philip A. Born ◽  
Georgia Koutsoumpli ◽  
Martin Ignacio Gonzalez-Rodriguez ◽  
Wouter L. J. Hinrichs ◽  
...  
Keyword(s):  
Clinical Trials ◽  
T Cell ◽  
Animal Models ◽  
Vaccine Development ◽  
Animal Experiments ◽  
T Cell Responses ◽  
T Cell Subsets ◽  
Vaccine Candidates ◽  
Cell Responses

Vaccine development is an expensive and time-consuming process that heavily relies on animal models. Yet, vaccine candidates that have previously succeeded in animal experiments often fail in clinical trials questioning the predictive value of animal models. Alternative assay systems that can add to the screening and evaluation of functional characteristics of vaccines in a human context before embarking on costly clinical trials are therefore urgently needed. In this study, we have established an in vitro system consisting of long-term cultures of unfractionated peripheral blood mononuclear cells (PBMCs) from healthy volunteers to assess (recall) T cell responses to vaccine candidates. We observed that different types of influenza vaccines (whole inactivated virus (WIV), split, and peptide vaccines) were all able to stimulate CD4 and CD8 T cell responses but to different extents in line with their reported in vivo properties. In-depth analyses of different T cell subsets revealed that the tested vaccines evoked mainly recall responses as indicated by the fact that the vast majority of the responding T cells had a memory phenotype. Furthermore, we observed vaccine-induced activation of T follicular helper cells, which are associated with the induction of humoral immune responses. Our results demonstrate the suitability of the established PBMC-based system for the in vitro evaluation of memory T cell responses to vaccines and the comparison of vaccine candidates in a human immune cell context. As such, it can help to bridge the gap between animal experiments and clinical trials and assist in the selection of promising vaccine candidates, at least for recall antigens.

scholarly journals Attenuated dengue viruses are genetically more diverse than their respective wild-type parents

npj Vaccines ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Amanda Makha Bifani ◽  
Milly M. Choy ◽  
Hwee Cheng Tan ◽  
Eng Eong Ooi
Keyword(s):  
Clinical Trials ◽  
Vaccine Development ◽  
Infectious Clone ◽  
Phase 1 ◽  
Genomic Diversity ◽  
Genome Diversity ◽  
Wild Type ◽  
Safety Outcome ◽  
Significant Burden

AbstractDengue poses a significant burden of individual health, health systems and the economy in dengue endemic regions. As such, dengue vaccine development has been an active area of research. Previous studies selected attenuated vaccine candidates based on plaque size. However, these candidates led to mixed safety outcome in clinical trials, suggesting it is insufficiently informative as an indicator of dengue virus (DENV) attenuation. In this study, we examined the genome diversity of wild-type DENVs and their attenuated derivatives developed by Mahidol University and tested in phase 1 clinical trials. We found that the attenuated DENVs, in particular the strain under clinical development by Takeda Vaccines, DENV2 PDK53, showed significantly higher genome diversity than its wild-type parent, DENV2 16681. The determinant of genomic diversity was intrinsic to the PDK53 genome as infectious clone of PDK53 showed greater genomic diversity after a single in vitro passage compared to 16681 infectious clone. Similar trends were observed with attenuated DENV1 and DENV4, both of which were shown to be attenuated clinically, but not DENV3 that was not adequately attenuated clinically. Taken together, evidence presented here suggests that genome diversity could be developed into a marker of DENV attenuation.

The role of aromatic microbial metabolites

2018 ◽  
pp. 97-108
Author(s):  
Н.В. Белобородова ◽  
В.В. Мороз ◽  
А.Ю. Бедова
Keyword(s):  
Process Integration ◽  
Biological Effects ◽  
Clinical Findings ◽  
Multiple Organ ◽  
Critical Conditions ◽  
Clear Understanding ◽  
Microbial Metabolites ◽  
Blood Concentrations

Интеграция метаболизма макроорганизма и его микробиоты, обеспечивающая в норме симбиоз и саногенез, нарушается при заболеваниях, травме, критическом состоянии, и вектор взаимодействия может изменяться в пользу прокариотов по принципу «метаболиты бактерий - против хозяина». Анализ литературы показал, что, с одной стороны, имеется живой интерес к ароматическим микробным метаболитам, с другой - отсутствует четкое представление об их роли в организме человека. Публикации, касающиеся ряда ароматических микробных метаболитов (фенилкарбоновых кислот, ФКК), как правило, не связаны между собой по тематике и направлены на решение тех или иных прикладных задач в разных областях биологии и медицины. Цель обзора - анализ информации о происхождении, биологических эффектах ФКК в экспериментах in vitro и in vivo , и клинических наблюдениях. Обобщая результаты приведенных в обзоре исследований на клеточном, субклеточном и молекулярном уровнях, логично предположить участие ароматических микробных метаболитов в патогенезе полиорганной недостаточности при сепсисе. Наиболее перспективным для раскрытия роли ароматических микробных метаболитов представляется изучение механизмов вторичной почечной недостаточности и септической энцефалопатии. Важным направлением для будущих исследований является изучение влияния продуктов микробной биодеградации ароматических соединений на развитие диссеминированного внутрисосудистого свертывания крови, артериальной гипотензии и септического шока. Результаты дальнейших исследований будут иметь не только фундаментальное значение, но и обогатят практическую медицину новыми диагностическими и лечебными технологиями. Significant increases in blood concentrations of some aromatic metabolites (phenylcarboxylic acids, PhCAs) in patients with sepsis have been previously shown. Enhanced bacterial biodegradation of aromatic compounds has been demonstrated to considerably contribute to this process. Integration of macroorganism metabolism and its microbiota, which provides normal symbiosis and sanogenesis, is disturbed in diseases, trauma, and critical conditions. Direction of this interaction may change in favor of prokaryotes according to the principle, “bacterial metabolites are against the host”. Analysis of literature showed a particular interest of many investigators to aromatic microbial metabolites. However, there is no clear understanding of their role in the human body. Publications on PhCAs are generally not thematically interrelated and usually focus on solving applied tasks in different fields of biology and medicine. The aim of this work was to consolidate existing information about origin and biological effects of PhCAs in in vitro / in vivo experiments and some clinical findings. The presented summary of reported data from studies performed at cellular, sub-cellular, and molecular levels suggests participation of aromatic microbial metabolites in the pathogenesis of multiple organ failure in sepsis. Studying mechanisms of secondary renal failure and septic encephalopathy is most promising for discovering the function of aromatic microbial metabolites. Effects of microbial biodegradation products of aromatic substances on development of disseminated intravascular coagulation, hypotension, and septic shock are an important challenge for future studies. Results of further investigations will be not only fundamental, but will also enrich medical practice with new diagnostic and therapeutic technologies.

Solubility Enhancement of Poorly Water-Soluble Antifungal Drug Acyclovir by Nanocrystal Formulation Approach

2018 ◽  
Vol 11 (2) ◽  
pp. 4036-4042
Author(s):  
Prakash Goudanavar ◽  
Ankit Acharya ◽  
Vinay C.H
Keyword(s):  
Chemical Interaction ◽  
Research Work ◽  
Antiviral Drug ◽  
In Vitro Release ◽  
Oral Route ◽  
Water Soluble ◽  
Precipitation Method ◽  
Dsc Studies ◽  
Ft Ir

Administration of an antiviral drug, acyclovir via the oral route leads to low and variable bioavailability (15-30%). Therefore, this research work was aimed to enhance bioavailability of acyclovir by nanocrystallization technique. The drug nanocrystals were prepared by anti-solvent precipitation method in which different stabilizers were used. The formed nanocrystals are subjected to biopharmaceutical characterization including solubility, particle size and in-vitro release. SEM studies showed nano-crystals were crystalline nature with sharp peaks. The formulated drug nanocrystals were found to be in the range of 600-900nm and formulations NC7 and NC8 showed marked improvement in dissolution velocity when compared to pure drug, thus providing greater bioavailability. FT-IR and DSC studies revealed the absence of any chemical interaction between drug and polymers used. 

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