siRNA Therapeutics for the Therapy of COVID-19 and Other Coronaviruses.

The ongoing pandemic of global concern has killed about three million humans and affected around 151 million people worldwide, as of April 30, 2021. Although recently approved vaccines for COVID-19 are engendering hope, finding new ways to cure the viral pandemic is still a quest for researchers worldwide. Major pandemics in history have been of viral origin, such as SARS, MERS, H1NI, Spanish flu, and so on. A larger emphasis has been on discovering potential vaccines, novel antiviral drugs, and agents that can mitigate the viral infection symptoms; however, a relatively new area, RNA interference (RNAi), has proven effective as an antiviral agent. The RNAi phenomenon has been largely exploited to cure cancer, neurodegenerative diseases, and some rare diseases. The U.S. Food and Drug Administration has recently approved three siRNA products for human use that garner significant hope in siRNA therapeutics for coronaviruses. There have been some commentaries and communications addressing this area. We have summarized and illustrated the significance and the potential of the siRNA therapeutics available as of April 30, 2021 to combat the ongoing viral pandemic and the emerging new variants such as B.1.1.7 and B.1.351. Numerous successful in vitro studies and several investigations to address the clinical application of siRNA therapeutics provide great hope in this field. This seminal Review describes the significance of siRNA-based therapy to treat diverse viral infections in addition to the current coronavirus challenge. In addition, we have thoroughly reviewed the patents approved for coronaviruses, the major challenges in siRNA therapy, and the potential approaches to address them, followed by innovation and prospects.

Drug Discovery of Nucleos(t)ide Antiviral Agents: Dedicated to Prof. Dr. Erik De Clercq on Occasion of His 80th Birthday.

Nucleoside and nucleotide analogues are essential antivirals in the treatment of infectious diseases such as human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), herpes simplex virus (HSV), varicella-zoster virus (VZV), and human cytomegalovirus (HCMV). To celebrate the 80th birthday of Prof. Dr. Erik De Clercq on 28 March 2021, this review provides an overview of his contributions to eight approved nucleos(t)ide drugs: (i) three adenosine nucleotide analogues, namely tenofovir disoproxil fumarate (Viread®) and tenofovir alafenamide (Vemlidy®) against HIV and HBV infections and adefovir dipivoxil (Hepsera®) against HBV infections; (ii) two thymidine nucleoside analogues, namely brivudine (Zostex®) against HSV-1 and VZV infections and stavudine (Zerit®) against HIV infections; (iii) two guanosine analogues, namely valacyclovir (Valtrex®, Zelitrex®) against HSV and VZV and rabacfosadine (Tanovea®-CA1) for the treatment of lymphoma in dogs; and (iv) one cytidine nucleotide analogue, namely cidofovir (Vistide®) for the treatment of HCMV retinitis in AIDS patients. Although adefovir dipivoxil, stavudine, and cidofovir are virtually discontinued for clinical use, tenofovir disoproxil fumarate and tenofovir alafenamide remain the most important antivirals against HIV and HBV infections worldwide. Overall, the broad-spectrum antiviral potential of nucleos(t)ide analogues supports their development to treat or prevent current and emerging infectious diseases worldwide.

En el mes de la concesión de los Premios Nobel, rendimos homenaje a Alfred Nobel y a los galardonados con el Premio de Fisiología y Medicina de 2020 / In the month of the Nobel Prize Awards, we pay tribute to Alfred Nobel and to the recipients of the 2020 Prize in Physiology and Medicine

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Potential Targets for Treatment of Coronavirus Disease 2019 (COVID-19): A Review of Qing-Fei-Pai-Du-Tang and Its Major Herbs.

COVID-19 has been declared a pandemic by WHO on March 11, 2020. No specific treatment and vaccine with documented safety and efficacy for the disease have been established. Hence it is of utmost importance to identify more therapeutics such as Chinese medicine formulae to meet the urgent need. Qing Fei Pai Du Tang (QFPDT), a Chinese medicine formula consisting of 21 herbs from five classical formulae has been reported to be efficacious on COVID-19 in 10 provinces in mainland China. QFPDT could prevent the progression from mild cases and shorten the average duration of symptoms and hospital stay. It has been recommended in the 6th and 7th versions of Clinical Practice Guideline on COVID-19 in China. The basic scientific studies, supported by network pharmacology, on the possible therapeutic targets of QFPDT and its constituent herbs including Ephedra sinica, Bupleurum chinense, Pogostemon cablin, Cinnamomum cassia, Scutellaria baicalensis were reviewed. The anti-oxidation, immuno-modulation and antiviral mechanisms through different pathways were collated. Two clusters of actions identified were cytokine storm prevention and angiotensin converting enzyme 2 (ACE2) receptor binding regulation. The multi-target mechanisms of QFPDT for treating viral infection in general and COVID-19 in particular were validated. While large scale clinical studies on QFPDT are being conducted in China, one should use real world data for exploration of integrative treatment with inclusion of pharmacokinetic, pharmacodynamic and herb-drug interaction studies.

Recent Trends in RSV Immunoprophylaxis: Clinical Implications for the Infant.

Respiratory syncytial virus (RSV) remains the leading cause for hospitalizations in infants worldwide, resulting in significant health and financial burden. Since 1998, the humanized monoclonal antibody palivizumab remains the only available option licensed for the prevention of severe RSV disease in high-risk children, namely premature infants and those with chronic lung disease and congenital heart disease. In 2014, the American Academy of Pediatrics modified the recommendations on the use of RSV prophylaxis in these high-risk children, and limited its use to premature infants born at < 28 weeks' gestational age (wGA). Following this last guidance update, studies have confirmed that premature infants of 29 to 34 wGA remain at high risk for severe RSV disease, especially those of younger chronologic age. New and more cost-effective strategies are being developed that would help alleviate both the health and financial burden associated with severe RSV disease.

Influenza update 2018-2019: 100 years after the great pandemic.

Four influenza pandemics, starting with the historic 1918 pandemic, have killed thousands of people around the world. Vaccination, still the most important means of preventing influenza, is currently recommended yearly for all people age 6 months and older, with a goal of vaccinating 80% of all Americans and 90% of at-risk populations. Neuraminidase inhibitors are underused, and a new drug with a different mechanism of action, baloxavir marboxil, is expected to be approved soon in the United States.

100 Years of Medical Countermeasures and Pandemic Influenza Preparedness.

The 1918 influenza pandemic spread rapidly around the globe, leading to high mortality and social disruption. The countermeasures available to mitigate the pandemic were limited and relied on nonpharmaceutical interventions. Over the past 100 years, improvements in medical care, influenza vaccines, antiviral medications, community mitigation efforts, diagnosis, and communications have improved pandemic response. A number of gaps remain, including vaccines that are more rapidly manufactured, antiviral drugs that are more effective and available, and better respiratory protective devices.

Innovation and trends in the development and approval of antiviral medicines: 1987-2017 and beyond.

2017 marked the 30th anniversary of the approval of zidovudine (AZT) as the first HIV/AIDS therapy. Since then, more than eighty antiviral drugs have received FDA approval, half of which treat HIV infection. Here, we provide a retrospective analysis of approved antiviral drugs, including therapeutics against other major chronic infections such as hepatitis B and C, and herpes viruses, over the last thirty years. During this time, only a few drugs were approved to treat acute viral infections, mainly influenza. Analysis of these approved antiviral drugs based on molecular class and mode of action shows that a large majority are small molecules and direct-acting agents as opposed to proteins, peptides, or oligonucleotides and host-targeting therapies. In addition, approvals of combination therapies accelerated over the last five years. We also provide a prospective study of future potential antiviral therapies, based on current clinical research pipelines across the pharmaceutical industry. Comparing past drug approvals with current clinical candidates hints at the future evolution in antiviral therapies and reveals how antiviral medicines are often discovered. Overall, this work helps forecast future trends and innovation in the field of antiviral research and development.

An Industry Perspective on Dengue Drug Discovery and Development.

Dengue is the most important mosquito-borne viral disease in the world, representing a major unmet medical need and a growing public health concern. The disease imposes a heavy burden to the affected individuals, to the health care systems, and to the economies of endemic countries. Vector control is the most widespread tool to curb dengue epidemics, but has been insufficient. Therefore, additional means such as vaccines and antivirals are required to aid in a coordinated response. The discovery and development of small molecule dengue virus inhibitors as a tool to prevent and/or treat dengue disease faces major hurdles in combining pan-serotypic efficacy, safety, and optimal drug-like properties. Moreover, the financial return of dengue drug projects may not compensate for the initial investment in research and development. This review article addresses the efforts undertaken to face the dengue epidemics, focusing on antiviral drug development. The dengue drug research and development process is described in detail and a dengue antiviral target product profile is proposed. The article discusses collaborations between the different players in the research field: government and government-sponsored organizations, pharmaceutical and biotechnology companies, academia, and non-profit and philanthropic organizations. Public-private partnerships are proposed as a model to boost dengue research and development towards an approved antiviral drug in the near future.

[Synthesis, conformation, and spectroscopy of nucleoside analogues concerning their antiviral activity]. / Synteza, konformacja i spektroskopia analogów nukleozydów oraz ich aktywnosc antywirusowa.

Chemically modified analogues of nucleosides and nucleotides, have been thoroughly investigated since the discovery of DNA double helix by Watson and Crick in 1953 (Nature 171: 737). Chemical structures, first of all tautomerism, of the nucleic acid bases, as well as the conformations of the nucleic acids constituents, determine the secondary and tertiary structures of DNA and RNA polymers. Similarly, structural and dynamic parameters of nucleoside derivatives determine their biological activity in mutagenesis, neoplastic transformation, as well as antiviral or anticancer properties. In this review, a multidisciplinary approach of Prof. David Shugar's group is presented in the studies on nucleosides and nucleotides. It consists in chemical syntheses of suitable analogues, measurements of physicochemical and spectral parameters, conformational analysis by means of nuclear magnetic resonance (NMR) and X-ray diffraction, as well as characteristics of the nucleoside analogues as inhibitors of some selected, target enzymes, crucial in respect to antiviral activity of the analogues. These long-lasting studies follows upon the line of the main paradigm of molecular biophysics, i. e. structure-activity relationship.

Antiviral adhesion molecular mechanisms for influenza: W. G. Laver's lifetime obsession.

Infection by the influenza virus depends firstly on cell adhesion via the sialic-acid-binding viral surface protein, haemagglutinin, and secondly on the successful escape of progeny viruses from the host cell to enable the virus to spread to other cells. To achieve the latter, influenza uses another glycoprotein, the enzyme neuraminidase (NA), to cleave the sialic acid receptors from the surface of the original host cell. This paper traces the development of anti-influenza drugs, from the initial suggestion by MacFarlane Burnet in 1948 that an effective 'competitive poison' of the virus' NA might be useful in controlling infection by the virus, through to the determination of the structure of NA by X-ray crystallography and the realization of Burnet's idea with the design of NA inhibitors. A focus is the contribution of the late William Graeme Laver, FRS, to this research.