Brief insight into the in silico properties, structure-activity relationships and biotransformation of fruquintinib, an anticancer drug of a new generation containing a privileged benzofuran scaffold.

Current trends in drug design notably consider so-called privileged scaffolds as the core structural fragments with decisive impact on affinity to properly chosen biological targets, potency, selectivity and toxicological characteristics of drugs and prospective drug candidates. Fruquintinib (1) is a novel synthetic selective inhibitor of vascular endothelial growth factor receptor (VEGFR) isoforms, i.e., VEGFR-1, VEGFR-2 and VEGFR-3. The therapeutic agent (1) consists of a flat bicyclic heteroaromatic ring, in which two nitrogens are suitablyincorporated, a core bicyclic heteroaromatic ring - privileged (substituted) benzofuran scaffold, and a pair of hydrogen bond (H-bond) donor and acceptor group, i.e., amide functional moiety. Fruquintinib (1) was first approved in China for the treatment of metastatic colorectal cancer, a severe malignant disease with a high mortality rate. The review article offered a brief insight into the topic of privileged structures, their drug- -like ranges of several parameters, pharmacodynamic characteristics of fruquintinib (1) and various in silico descriptors characterizing drug's structural and physicochemical properties (molecular weight, number of heavy atoms, number of aromatic heavy atoms, fraction of sp3 C-atoms, number of H-bond acceptors, number of H-bond donors, total polar surface area, molar refractivity, molecular volume as well as parameters of lipophilicity and solubility). Some of these descriptors were related to pharmacokinetics and distribution of fruquintinib (1), and, in addition, might help predict its ability to cross passively the blood-brain barrier (BBB). Moreover, a possible connection between the induction potential on cytochrome P450 isoenzymes (CYP1A2 and CYP3A4) and passive transport of a given drug into the central nervous system via BBB was investigated. Current clinical experience and future directions regarding of fruquintinib (1) were also briefly outlined.

The efficacy of triazavirin (riamilovir)-based treatment for coronavirus disease 2019 (COVID-19) in clinical trials and preliminary practical experiences.

Coronavirus disease 2019 (COVID-19) caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has plagued the human population as 2019 turned into 2020, when first cases were confirmed to be infected with the pathogen in Wuhan City, the largest mega-city and capital of Hubei Province in Central China. Since this time, many pharmacotherapeutic modalities were suggested and used to treat the patients suffering from COVID-19. Triazavirin (TZV; riamilovir) is a synthetic non-toxic broad-spectrum antiviral drug belonging into an azolotriazine class. Several hypotheses and suggestions based on the knowledge about morphology, structure of virion, genome, replication cycle and functions of particular proteins within SARS-CoV-2 as well as in silico analyzes were published aiming to employ TZV for the treatment of COVID-19. Results and conclusions from a well-known randomized controlled trial registered under the Registration No. ChiCTR2000030001, which was carried out in China in 2020, indicated not only the anti-SARS-CoV-2 efficacy of given aza analogue of guanine but also some limitations of these outcomes in the context of their general interpretability and applicability. Thus, a primary aim of this review article was to provide more complex view on pharmacotherapeutic interventions based on TZV against COVID-19/SARS-CoV-2. The focus was on relevant results and conclusions from clinical trials as well as practical experiences with given antiviral agent considering not only real benefits of chosen therapeutic strategies but also several obstacles connected with them.

Telacebec (Q203): Is there a novel effective and safe anti-tuberculosis drug on the horizon?

High prevalence and stronger emergency of various forms of drug-resistant tuberculosis (DR-TB), including the multidrug-resistant (MDR-TB) as well as extensively drug-resistant (XDR-TB) ones, caused by variously resistant Mycobacterium tuberculosis pathogens, make first-line anti-tuberculosis (anti-TB) agents therapeutically more and more ineffective. Therefore, there is an imperative to develop novel highly efficient (synthetic) agents against both drug-sensitive-TB and DR-TB. The exploration of various heterocycles as prospective core scaffolds for the discovery, development and optimization of anti-TB drugs remains an intriguing scientific endeavour. Telacebec (Q203; TCB), a molecule containing an imidazo[1,2-a]pyridine-3-carboxamide (IPA) structural motif, is considered a novel very promising anti-TB agent showing a unique mechanism of action. The compound blocks oxidative phosphorylation by inhibiting a mycobacterial respiratory chain due to interference with a specific cytochrome b subunit (QcrB) of transmembrane bc1 menaquinol-cytochrome c oxidoreductase as an essential component for transporting electrons across the membrane from menaquinol to other specific subunit, cytochrome c (QcrC). Thus, the ability of mycobacteria to synthesize adenosine-5´-triphosphate is limited and energy generating machinery is disabled. The TCB molecule effectively fights drug-susceptible, MDR as well as XDR M. tuberculosis strains. The article briefly explains a mechanism of an anti-TB action related to the compounds containing a variously substituted IPA scaffold and is focused on their fundamental structure-anti-TB activity relationships as well. Special consideration is paid to TCB indicating the importance of particular structural fragments for maintaining (or even improving) favourable pharmacodynamic, pharmacokinetic and/or toxicological properties. High lipophilicity of TCB might be regarded as one of the key physicochemical properties with positive impact on anti-TB effect of the drug. In January 2021, the TCB molecule was also involved in phase-II clinical trials focused on the treatment of Coronavirus Disease-19 caused by Severe Acute Respiratory Syndrome Coronavirus 2.

Telacebec (Q203): Is there a novel effective and safe anti-tuberculosis drug on the horizon?

High prevalence and stronger emergency of various forms of drug-resistant tuberculosis (DR-TB), including the multidrug-resistant (MDR-TB) as well as extensively drug-resistant (XDR-TB) ones, caused by variously resistant Mycobacterium tuberculosis pathogens, make first-line anti-tuberculosis (anti-TB) agents therapeutically more and more ineffective. Therefore, there is an imperative to develop novel highly efficient (synthetic) agents against both drug-sensitive-TB and DR-TB. The exploration of various heterocycles as prospective core scaffolds for the discovery, development and optimization of anti-TB drugs remains an intriguing scientific endeavour. Telacebec (Q203; TCB), a molecule containing an imidazo[1,2-a]pyridine-3-carboxamide (IPA) structural motif, is considered a novel very promising anti-TB agent showing a unique mechanism of action. The compound blocks oxidative phosphorylation by inhibiting a mycobacterial respiratory chain due to interference with a specific cytochrome b subunit (QcrB) of transmembrane bc1 menaquinol-cytochrome c oxidoreductase as an essential component for transporting electrons across the membrane from menaquinol to other specific subunit, cytochrome c (QcrC). Thus, the ability of mycobacteria to synthesize adenosine-5´-triphosphate is limited and energy generating machinery is disabled. The TCB molecule effectively fights drug-susceptible, MDR as well as XDR M. tuberculosis strains. The article briefly explains a mechanism of an anti-TB action related to the compounds containing a variously substituted IPA scaffold and is focused on their fundamental structure-anti-TB activity relationships as well. Special consideration is paid to TCB indicating the importance of particular structural fragments for maintaining (or even improving) favourable pharmacodynamic, pharmacokinetic and/or toxicological properties. High lipophilicity of TCB might be regarded as one of the key physicochemical properties with positive impact on anti-TB effect of the drug. In January 2021, the TCB molecule was also involved in phase-II clinical trials focused on the treatment of Coronavirus Disease-19 caused by Severe Acute Respiratory Syndrome Coronavirus 2.

Ingavirin might be a promising agent to combat Severe Acute Respiratory Coronavirus 2 (SARS-CoV-2).

The Severe Acute Respiratory Coronavirus 2 (SARS--CoV-2) and Coronavirus Disease-19 (COVID-19) pandemic, caused by the virus, have changed the world in just half a year. Lack of effective treatment, coupled with etiology of COVID-19, has resulted in more than 500,000 confirmed deaths at the time of writing, and the global economy is at an unseen unprecedented low level with unknown near- and long-term consequences. Ingavirin has been considered a non-toxic broad-spectrum antiviral with a complex mechanism of action. The molecule was originally designed for the prophylaxis and treatment of flu caused by both Influenza A and B viruses and for the treatment of viral causes of acute respiratory illness. The article hypothesized that the efficiency of given 1H-imidazol-4-yl heterocyclic scaffold-containing compound against SARS-CoV-2 might be connected with its ability to interfere with specific heterogeneous nuclear ribonucleoproteins (A1, for example). These specific cellular RNA-binding proteins showed affinity to Severe Acute Respiratory Coronavirus (SARS-CoV) nucleocapsid (N) protein, which shared high homology with the N protein of SARS-CoV-2 and the fact was expressed by a sequence identity of 90.52%. Impairing of the interactions between nuclear ribonucleoproteins and nucleocapsid (N) protein of SARS-CoV-2 might result in the inhibition of a viral replication cycle. Additional immunomodulating properties of ingavirin could be favorable for induction of adaptive immunity of host cells.