Research Finds Covid Antiviral Drug Linked to Transmitting Mutations

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A revolutionary drug developed by the renowned US pharmaceutical company Merck to combat Covid-19 has been found to be associated with mutations that are transmitted between patients, raising questions about its efficacy and the substantial investment made by governments worldwide for its procurement.

In a comprehensive analysis of 15 million coronavirus sequences, researchers discovered that mutations escalated in 2022 following the introduction of molnupiravir, also known as Lagevrio, in numerous nations. The mutations were particularly prevalent among older age groups, individuals at a higher risk of severe illness who were taking molnupiravir, and countries where the antiviral treatment was extensively employed.

Concerns about the effectiveness of antiviral drugs in treating Covid-19 will undoubtedly be amplified as health authorities brace themselves for a busy autumn, with a surge in cases triggered by Omicron subvariants containing a multitude of mutations.

The researchers, representing esteemed institutions such as the Francis Crick Institute, the universities of Cambridge, Liverpool, and Cape Town, Imperial College London, and the UK Health Security Agency, correlated these genetic mutations with the characteristics observed during clinical trials of molnupiravir.

Theo Sanderson, lead author and postdoctoral researcher at the Francis Crick Institute, stated, “Molnupiravir treatment can sometimes lead to the formation of viruses carrying a substantial number of mutations, yet these viruses remain viable and, in certain cases, transmissible.” Sanderson emphasized the importance of considering the possibility of persistent antiviral-induced mutations when developing similar drugs.

Antiviral medications are designed to target viruses, thereby preventing them from infecting healthy cells and aiding the immune system in fighting off the infection. Molnupiravir, marketed by Merck in collaboration with US biotech group Ridgeback Biotherapeutics, operates by introducing minor mutations in the virus itself.

The peer-reviewed study, published in Nature, also identified clusters of mutations capable of transmission between patients, although the genetic signature is not associated with any current variants of concern. The rise in cases associated with Omicron variants such as BA. 2.86 has not been linked to the use of molnupiravir.

The European Medicines Agency refused to grant marketing authorization for molnupiravir, a development initially reported by the Financial Times in 2022. Consequently, its usage in Western countries has become extremely limited. Merck initially contested this decision but subsequently withdrew its appeal.

In the United States, the Food and Drug Administration granted emergency use authorization for certain patient categories in late 2021.

Despite these setbacks, Merck recorded sales exceeding $6 billion between 2021 and 2022, excluding sales in developing markets where generic versions of the drug are produced under license.

Andrew Hill, a senior visiting research fellow at the pharmacology and therapeutics department of the University of Liverpool, highlighted potential side effects of the drug on pregnant women.

Furthermore, a clinical trial conducted in the UK last year indicated that the drug failed to demonstrate its ability to reduce the risk of hospitalization and death among adults at higher risk from the disease. This outcome was a significant disappointment following initial data indicating that molnupiravir could cut the risk of death or hospitalization in half, a figure later revised to approximately 30 percent.

In response to the study, Merck informed the FT that the authors themselves had acknowledged limitations in their research and that the company remained “confident” in the drug’s clinical profile.