Discovery of Novel Bicyclic[3.3.0]proline Peptidyl α-Ketoamides as Potent 3CL-Protease Inhibitors for SARS-CoV-2

On the origins of SARS-CoV-2 main protease inhibitors

In order to address the world-wide health challenge caused by the COVID-19 pandemic, the 3CL protease/SARS-CoV-2 main protease (SARS-CoV-2-Mpro) coded by its nsp5 gene became one of the biochemical targets for the design of antiviral drugs. In less than 3 years of research, 4 inhibitors of SARS-CoV-2-Mpro have actually been authorized for COVID-19 treatment (nirmatrelvir, ensitrelvir, leritrelvir and simnotrelvir) and more such as EDP-235, FB-2001 and STI-1558/Olgotrelvir or five undisclosed compounds (CDI-988, ASC11, ALG-097558, QLS1128 and H-10517) are undergoing clinical trials. This review is an attempt to picture this quite unprecedented medicinal chemistry feat and provide insights on how these cysteine protease inhibitors were discovered. Since many series of covalent SARS-CoV-2-Mpro inhibitors owe some of their origins to previous work on other proteases, we first provided a description of various inhibitors of cysteine-bearing human caspase-1 or cathepsin K, as well as inhibitors of serine proteases such as human dipeptidyl peptidase-4 or the hepatitis C protein complex NS3/4A. This is then followed by a description of the results of the approaches adopted (repurposing, structure-based and high throughput screening) to discover coronavirus main protease inhibitors.

Small-molecule anti-COVID-19 drugs and a focus on China's homegrown mindeudesivir (VV116)

The coronavirus disease 2019 (COVID-19) pandemic has stimulated tremendous efforts to develop therapeutic agents that target severe acute respiratory syndrome coronavirus 2 to control viral infection. So far, a few small-molecule antiviral drugs, including nirmatrelvir-ritonavir (Paxlovid), remdesivir, and molnupiravir have been marketed for the treatment of COVID-19. Nirmatrelvir-ritonavir has been recommended by the World Health Organization as an early treatment for outpatients with mild-to-moderate COVID-19. However, the existing treatment options have limitations, and effective treatment strategies that are cost-effective and convenient for tackling COVID-19 are still needed. To date, four domestically developed oral anti-COVID-19 drugs have been granted conditional market approval in China. These drugs include azvudine, simnotrelvir-ritonavir (Xiannuoxin), leritrelvir, and mindeudesivir (VV116). Preclinical and clinical studies have explored the efficacy and tolerability of mindeudesivir and supported its early use in mild-to-moderate COVID-19 cases at high risk for progression. In this review, we discuss the most recent findings regarding the pharmacological mechanism and therapeutic effects focusing on mindeudesivir and other small-molecule antiviral agents for COVID-19. These findings will expand our understanding and highlight the potential widespread application of China's homegrown anti-COVID-19 drugs.