Optimization of potent, broad-spectrum, and specific anti-influenza compounds targeting RNA polymerase PA-PB1 heterodimerization.

Influenza viruses (IV) are single-stranded RNA viruses with a negative-sense genome and have the potential to cause pandemics. While vaccines exist for influenza, their protection is only partial. Additionally, there is only a limited number of approved anti-IV drugs, which are associated to emergence of drug resistance. To address these issues, for years we have focused on the development of small-molecules that can interfere with the heterodimerization of PA and PB1 subunits of the IV RNA-dependent RNA polymerase (RdRP). In this study, starting from a cycloheptathiophene-3-carboxamide compound that we recently identified, we performed iterative cycles of medicinal chemistry optimization that led to the identification of compounds 43 and 45 with activity in the nanomolar range against circulating A and B strains of IV. Mechanistic studies demonstrated the ability of 43 and 45 to interfere with viral RdRP activity by disrupting PA-PB1 subunits heterodimerization and to bind to the PA C-terminal domain through biophysical assays. Most important, ADME studies of 45 also showed an improvement in the pharmacokinetic profile with respect to the starting hit.

SARS-CoV-2 and influenza virus coinfections in the Tuscan population during the 2021/2022 influenza season.

Introduction: The 2021/2022 influenza season was not characterised by a well-defined incidence peak. As reported by the Italian National Institute of Health, a high value of incidence of influenza cases was recorded in week 13, but it was still lower than in other influenza seasons. This abnormal circulation was probably due to relaxation of the COVID-19 pandemic restriction measures, such as social distancing, smart-working, home leaning and the use of masks, which greatly reduced the circulation of respiratory-transmitted viruses, including human respiratory syncytial virus (HRSV). The symptoms of SARS-CoV-2 and influenza are quite similar, sharing the human-to-human transmission route via respiratory droplets. Methods: The aim of this study was to estimate the rate of coinfection with influenza viruses and/or HRSV in SARS-CoV-2-positive subjects (N = 940) in a population of central Italy during the 2021/2022 season. Results: A total of 54 cases of coinfection were detected during the study period, 51 cases (5.4%) of SARS-CoV-2 and influenza virus and three cases (0.3%) of SARS-CoV-2 and HRSV coinfection. Conclusions: These results highlight the importance of continuous monitoring of the circulation of influenza virus and other respiratory viruses in the context of the COVID-19 pandemic.

Incorporating temporal dynamics of mutations to enhance the prediction capability of antiretroviral therapy's outcome for HIV-1.

MOTIVATION: In predicting HIV therapy outcomes, a critical clinical question is whether using historical information can enhance predictive capabilities compared with current or latest available data analysis. This study analyses whether historical knowledge, which includes viral mutations detected in all genotypic tests before therapy, their temporal occurrence, and concomitant viral load measurements, can bring improvements. We introduce a method to weigh mutations, considering the previously enumerated factors and the reference mutation-drug Stanford resistance tables. We compare a model encompassing history (H) with one not using this information (NH). RESULTS: The H-model demonstrates superior discriminative ability, with a higher ROC-AUC score (76.34%) than the NH-model (74.98%). Wilcoxon test results confirm significant improvement of predictive accuracy for treatment outcomes through incorporating historical information. The increased performance of the H-model might be attributed to its consideration of latent HIV reservoirs, probably obtained when leveraging historical information. The findings emphasize the importance of temporal dynamics in acquiring mutations. However, our result also shows that prediction accuracy remains relatively high even when no historical information is available. AVAILABILITY AND IMPLEMENTATION: This analysis was conducted using the Euresist Integrated DataBase (EIDB). For further validation, we encourage reproducing this study with the latest release of the EIDB, which can be accessed upon request through the Euresist Network.

Serendipitous Identification of Azine Anticancer Agents Using a Privileged Scaffold Morphing Strategy.

The use of privileged scaffolds as a starting point for the construction of libraries of bioactive compounds is a widely used strategy in drug discovery and development. Scaffold decoration, morphing and hopping are additional techniques that enable the modification of the chosen privileged framework and better explore the chemical space around it. In this study, two series of highly functionalized pyrimidine and pyridine derivatives were synthesized using a scaffold morphing approach consisting of triazine compounds obtained previously as antiviral agents. Newly synthesized azines were evaluated against lymphoma, hepatocarcinoma, and colon epithelial carcinoma cells, showing in five cases acceptable to good anticancer activity associated with low cytotoxicity on healthy fibroblasts. Finally, ADME in vitro studies were conducted on the best derivatives of the two series showing good passive permeability and resistance to metabolic degradation.

In Vitro Combinatorial Activity of Direct Acting Antivirals and Monoclonal Antibodies against the Ancestral B.1 and BQ.1.1 SARS-CoV-2 Viral Variants.

Combination antiviral therapy may be helpful in the treatment of SARS-CoV-2 infection; however, no clinical trial data are available, and combined use of direct-acting antivirals (DAA) and monoclonal antibodies (mAb) has been reported only anecdotally. To assess the cooperative effects of dual drug combinations in vitro, we used a VERO E6 cell-based in vitro system with the ancestral B.1 or the highly divergent BQ.1.1 virus to test pairwise combinations of the licensed DAA, including nirmatrelvir (NRM), remdesivir (RDV) and the active metabolite of molnupiravir (EIDD-1931) as well the combination of RDV with four licensed mAbs (sotrovimab, bebtelovimab, cilgavimab, tixagevimab; tested only with the susceptible B.1 virus). According to SynergyFinder 3.0 summary and weighted scores, all the combinations had an additive effect. Within DAA/DAA combinations, paired scores with the B.1 and BQ.1.1 variants were comparable. In the post hoc analysis weighting synergy by concentrations, several cases of highly synergistic scores were detected at specific drug concentrations, both for DAA/DAA and for RDV/mAb combinations. This was supported by in vitro confirmation experiments showing a more than a linear shift of a drug-effective concentration (IC50) at increasing concentrations of the companion drug, although the effect was prominent with DAA/DAA combinations and minimal or null with RDV/mAb combinations. These results support the cooperative effects of dual drug combinations in vitro, which should be further investigated in animal models before introduction into the clinic.

Switching the three-component Biginelli-like reaction conditions for the regioselective synthesis of new 2-amino[1,2,4]triazolo[1,5-a]pyrimidines.

Among the eight different triazolopyrimidine isomers existing in nature, 1,2,4-triazolo[1,5-a]pyrimidine (TZP) is one of the most studied and used isomers in medicinal chemistry. For some years, our group has been involved in developing regioselective one-pot procedures for the synthesis of 2-amino-7-aryl-5-methyl- and 2-amino-5-aryl-7-methyl-TZPs of interest in the preparation of antiviral agents. In this work, taking advantage of a Biginelli-like multicomponent reaction (MCR), we report the identification of finely tunable conditions to regioselectively synthesize C-6 ester-substituted amino-TZP analogues, both in dihydro and oxidized forms. Indeed, the use of mild acidic conditions is strongly directed toward the regioselective synthesis of 5-aryl-7-methyl C-6-substituted TZP analogues, while the use of neutral ionic liquids shifted the regioselectivity towards 7-aryl-5-methyl derivatives. In addition, the novel synthesized scaffolds were functionalized at the C-2 position and evaluated for their antiviral activity against RNA viruses (influenza virus, flaviviruses, and SARS-CoV-2). Compounds 25 and 26 emerged as promising anti-flavivirus agents, showing activity in the low micromolar range.