A worker holds a bottle of Merck & Co.’s antiviral drug Molnupiravir at a warehouse in Shoham, Israel, Jan. 18, 2022.
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A new study published on Monday says Merck’s widely used Covid antiviral pill can cause mutations in the virus that are occasionally transmitted to other people, raising questions about whether the drug has the potential to speed up the development of Covid .
The findings could add to scrutiny of the benefits of treatment molnupiravir, one of the first Covid drugs available to doctors worldwide during the pandemic.
Molnupiravir works by causing mutations in Covid’s genetic information, which weakens or destroys the virus and reduces the amount of Covid in the body. But the study, published Monday in the journal Nature, found that Covid can sometimes survive treatment with molnupiravir, leading to mutated versions of the virus that have been shown to spread to other patients.
Researchers in the US and UK specifically analyzed 15 million Covid genomes to see which mutations had occurred and when. They found that mutations increased in 2022 after the introduction of molnupiravir in many countries.
The study says there is no evidence that molnupiravir, sold under the brand name Lagevrio, has caused more transmissible or severe variants of Covid.
But the findings are important for regulators as they continue to assess the risks and benefits of molnupiravir, Theo Sanderson, the study’s lead author and a researcher at the Francis Crick Institute in London, wrote in a post on X, formerly Twitter.
A spokesman for Merck dismissed the new study, claiming that the researchers assumed the mutations they analyzed were associated with patients treated with molnupiravir, “without documented evidence of this transmission.”
“Instead, the authors rely on circumstantial relationships between the region from which the sequence was identified and the time frame of sequence collection in countries where molnupiravir is available to reach their conclusion,” the spokesperson said.
The spokesperson added that genomes with the mutations were “unusual and associated with sporadic cases.”
The company also disputed in February an earlier study by the same research team that suggested molnupiravir led to new mutations of the virus in some patients. Based on the data at the time, a Merck spokesman said it did not believe molnupiravir was likely to contribute to Covid mutations.
The new study comes at a time when Covid is regaining a stronger foothold in the US, largely due to newer strains of the virus.
But the U.S. and other countries appear to be relying less on molnupiravir to fend off Covid this year: Sales of the drug fell to about $200 million in Merck’s third quarter, an 83% decline from more than 1 billion US dollars in the same period of the year ago.
Merck’s molnupiravir has long been controversial because of its ability to cause genetic mutations.
The U.S. Food and Drug Administration first approved the drug for emergency use in late 2021. However, the FDA recommends against using Lagevrio during pregnancy because nonclinical studies suggest it could harm the fetus.
Molnupiravir is also not approved for use in patients under 18 years of age because it may affect bone and cartilage growth.
Source : www.cnbc.com