New direct-acting antiviral therapies have become essential because severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has developed worldwide, which is highly transmissible, pathogenic, and immune-resistant variants that worry healthcare providers. Research has identified main protease (MPro) as an optimal SARS-CoV-2 combat target, and both nirmatrelvir and ensitrelvir serve as active COVID-19 medications presently used for treatment. The ongoing evolution of SARS-CoV-2 demands new antiviral medicines with broad activity against multiple coronaviruses. Research has recently discovered AVI-4516 as an uracil-based nonpeptidic MPro inhibitor that demonstrates high effectiveness against SARS-CoV-2 and other human coronaviruses. The development of this inhibitor family represents a rational approach to face potential viral risks after controlling the present epidemic.
This study aims to develop a novel MPro inhibitor that can inhibit the SARS-CoV-2 virus. This finding provides valuable information about the inhibitor’s potential in future research. The study investigated different assays and screening methods to evaluate compounds for antiviral activity specifically against SARS-CoV-2.
The researchers examined AVI-4516 as a new MPro inhibitor to strengthen the existing SARS-CoV-2 antiviral prevention strategies. This study includes the dynamic light scattering (DLS), intact protein mass spectrometry, and NMR analysis to demonstrate the compound’s effectiveness against different viral entities. Permeability assessment used the parallel artificial membrane permeability assay (PAMPA) method, and the cytotoxicity screening was conducted on A549-ACE2h cells, and the antiviral activity testing was conducted via live-cell analysis. Crystallography and other structural analyses revealed that the compounds interact with SARS-CoV-2 MPro. The essential element of this research involved direct testing of the compounds against SARS-CoV-2 and other coronaviruses in living systems.
Experimental results revealed that AVI-4516 shows exceptional potency with an ICâ‚…â‚€ value of 29 nM, surpassing earlier analogs by a factor of 100. Research findings demonstrated that AVI-4516, when combined with molnupiravir, showed synergistic effects that support the potential use in combination COVID-19 drug treatments.
Testing of these compounds demonstrated their optimal pharmacological features, consisting of high bioavailability through oral administration in combination with low clearance rates and negligible cytochrome P450 enzyme effects for minimizing drug interaction risk. The study revealed that the new inhibitors contained a latent electrophilic factor that differentiated them from existing drugs, such as nirmatrelvir and ensitrelvir. The irreversible MPro inhibition properties of both AVI-4516 and related compounds allow for extended dosing with less frequent drug administration, making them ideal for longer treatment times.
Preclinical testing gave promising results, which suggest that C6-aryl compounds and other subcategories are leading candidates for antiviral development to treat both present and future coronavirus infections. AVI-4516 and its analogs present a substantial opportunity as pan-coronavirus therapeutic drugs which could lead to better treatments against SARS-CoV-2 and other coronavirus strains in future medical developments. The discovered data serve to advance antiviral investigation and prepare for intensifying viral outbreaks.
Reference: Detomasi TC, Degotte G, Huang S, et al. Structure-based discovery of highly bioavailable, covalent, broad-spectrum coronavirus MPro inhibitors with potent in vivo efficacy. Sci Adv. 2025;11(17):eadt7836. doi:10.1126/sciadv.adt7836
