The efficacy of Zafirlukast as a SARS-CoV-2 helicase inhibitor in adult patients with moderate COVID-19 Pneumonia (pilot randomized clinical trial).

OBJECTIVE: To assess the efficacy of Zafirlukast as a SARS-CoV-2 Helicase Inhibitor in adult patients with moderate COVID-19 symptoms (hospitalized patients with COVID-19 pneumonia who were not admitted to an intensive care unit). METHODS: We conducted a randomized, double blind, placebo-controlled, pilot trial with adult patients with moderate COVID-19 pneumonia. The sample was randomized to Zafirlukast 10 mg BD for 10 days plus standard care vs placebo plus standard care. The primary outcome was the complete resolution of all symptoms. The secondary outcomes were the duration of oxygen therapy, and length of hospital stay (LOS). RESULTS: In total, 40 patients were randomized (20 to Zafirlukast and 20 to the control). The time to the resolution of clinical symptoms in both groups was not significantly different. Regarding the fever, 0.3 days [95 % CI, - 1.19, 0.69], p = 0.76, for shortness of breath, the difference was 0.4 days [95 % CI, - 2.67, 3.46], p = 0.68, for cough the difference was 0.2 days [95 % CI, - 1.45, 1.95], p = 0.98, for sputum the difference was 0.5 days [95 % CI, - 0.75, 1.85], p = 0.09, for vomiting the difference was 0.1 days [95 % CI, - 0.50, 0.30], p = 0.93, for fatigue the difference was 0.3 days [95 % CI, - 4.32, 3.62], p = 0.64. The LOS per day for the two groups was not significantly different, 1.1 days [95 % CI,- 2.03, 4.28], p = 0.94, nor was the duration of oxygen therapy per days, 1.3 days [95 % CI, - 1.79, 4.49], p = 0.49. Regarding the 7 category ordinary scale, there was no significant difference between the two groups at day 7 (p-value = 0.62), day 14 (p-value = 0.60) and day 28 (p-value = 0.48). CONCLUSION: Among adult patients hospitalized with COVID-19 pneumonia, the treatment with Zafirlukast, compared to placebo, did not significantly improve symptoms resolution.

Anti-leukotriene drugs in the therapy of inflammatory diseases

A key part of many chronic diseases is inflammation controlled by inflammatory mediators. Regulation of their function allows muting the inflammatory response, which is the desired effect in the treatment of inflammatory diseases. The source of mediators is arachidonic acid, converted to pro-inflammatory mediators by cyclooxygenases (COX) or lipooxygenases (LOX). The 5-LOX pathway is full of target points for the regulation of biosynthesis of cysteinyl leukotrienes (CysLT) - one of the major classes of inflammatory mediators. These compounds exert their activity through specific leukotriene receptors - first (CysLT1R) and second (CysLT2R). Drugs that inhibit CysLT synthesis, as well as leukotriene receptor antagonists (LTRA), form a group of drugs known as anti-leukotriene drugs. Currently, only a few representatives of this group are available in the pharmacies around the world: The 5-LOX inhibitor - zileuton - and three CysLT1R antagonists - montelukast, pranlukast, and zafirlukast. LTRAs due to their wide range of anti-inflammatory effects are a group of drugs with a high potential in the treatment of inflammatory diseases. The study of new applications of known LTRAs and the search for new members of the LTRA group are the main directions of development in this field of pharmacy. This work summarizes the benefits of using anti-leukotriene drugs in the treatment of chronic diseases and presents new directions for using LTRAs.

Mutation Pattern in the Receptor Binding Motif of SARS-Cov-2 Variants and the Effect on Molecular Interactions in Docked Ligand Complexes

The spike glycoprotein of SARS-Cov-2 is a therapeutic target for Covid-19 and mutations in the Receptor Binding Motif (RBM) may alter the binding properties of ligands proposed to inhibit viral entry. This study aimed to identify the existence of a mutation pattern in the RBMs of SARS-Cov-2 variants and study the effect on ligand binding interactions. RBM sequences were obtained using NCBI BLASTP and subjected to multiple and pairwise sequence alignment analysis. Hypothetical generations were drawn from the phylogenetic tree. The effect of mutation on ligand binding was studied by docking zafirlukast on selected RBMs. Molecular dynamics simulations were conducted to explain molecular interactions. The sequences at the same phylogenetic level showed higher similarity with the observed differences defined by the crystallized chain length. 6XDG_E, a leaf node sequence was 76% similar to 7NXA_E, a branch from the root, and had the highest mutation. Differences in sequence similarity across successive generations were based on mutations and crystallized chain length and the amino acid substitution is not predictable. Different bond types and binding affinities were observed as well as varying Root Mean Square Deviation (RMSD), Root Mean Square Fluctuation (RMSF), and Region of Gyration (RoG) values for the RBMs in different variants. The RMSD, RMSF, and RoG did not differ significantly in the bound and free states of RBM from specific variants suggesting that the observed differences are attributable to amino acid substitutions. This information is crucial for drug development intended to block SARS-Cov-2 entry.

Discovery of Zafirlukast as a novel SARS-CoV-2 helicase inhibitor using in silico modelling and a FRET-based assay.

The coronavirus helicase is an essential enzyme required for viral replication/transcription pathways. Structural studies revealed a sulphate moiety that interacts with key residues within the nucleotide-binding site of the helicase. Compounds with a sulphoxide or a sulphone moiety could interfere with these interactions and consequently inhibit the enzyme. The molecular operating environment (MOE) was used to dock 189 sulphoxide and sulphone-containing FDA-approved compounds to the nucleotide-binding site. Zafirlukast, a leukotriene receptor antagonist used to treat chronic asthma, achieved the lowest docking score at -8.75 kcals/mol. The inhibitory effect of the compounds on the SARS-CoV-2 helicase dsDNA unwinding activity was tested by a FRET-based assay. Zafirlukast was the only compound to inhibit the enzyme (IC50 = 16.3 µM). The treatment of Vero E6 cells with 25 µM zafirlukast prior to SARS-CoV-2 infection decreased the cytopathic effects of SARS-CoV-2 significantly. These results suggest that zafirlukast alleviates SARS-CoV-2 pathogenicity by inhibiting the viral helicase and impairing the viral replication/transcription pathway. Zafirlukast could be clinically developed as a new antiviral treatment for SARS-CoV-2 and other coronavirus diseases. This discovery is based on molecular modelling, in vitro inhibition of the SARS-CoV helicase activity and cell-based SARS-CoV-2 viral replication.

AI drug discovery screening for COVID-19 reveals zafirlukast as a repurposing candidate.

AIMS: Over the past few years, AI has been considered as potential important area for improving drug development and in the current urgent need to fight the global COVID-19 pandemic new technologies are even more in focus with the hope to speed up this process. The purpose of our study was to identify the best repurposing candidates among FDA-approved drugs, based on their predicted antiviral activity against SARS-CoV-2. MATERIALS AND METHODS: This article describes a drug discovery screening based on a supervised machine learning model, trained on in vitro data encoded in chemical fingerprints, representing particular molecular substructures. Predictive performance of our model has been evaluated using so-called scaffold splits offering a state-of-the-art setup for assessing model's ability to generalize to new chemical spaces, critical for drug repurposing applications. KEY FINDINGS: Our study identified zafirlukast as the best repurposing candidate for COVID-19. SIGNIFICANCE: Zafirlukast could be potent against COVID-19 both due to its predicted antiviral properties and its ability to attenuate the so called cytokine storm. Thus, these two critical mechanisms of action may be combined in one drug as a novel and promising pharmacotherapy in the current pandemic.