An experimental antiviral pill developed by US drugmaker Merck & Co could reduce the risk of hospitalization or death due to severe COVID-19 by about half, interim clinical trial results suggest.
The tablet, molnupiravir, was given twice a day to patients recently diagnosed with the disease. The drugmaker Merck said its results were so positive that outside monitors had asked to stop the trial early.
Merck and its partner Ridgeback Biotherapeutics said that they would apply for emergency use authorization for the drug in the US in the next two weeks. If it gets approval, molnupiravir, which is designed to introduce errors into the genetic code of the virus, would be the first oral antiviral medication for COVID-19.
Dr. Anthony Fauci, the chief medical adviser to US President Joe Biden, stated that the results were “very good news”, but urged caution until the US Food and Drug Administration (FDA) had reviewed the data.
“An oral antiviral that can impact hospitalization risk to such a degree would be game-changing,” said Mr. Amesh Adalja, senior scholar at the Johns Hopkins Center for Health Security. The existing treatments are “cumbersome and logistically challenging to administer. A simple oral pill would be the opposite of that,” he added.
Pfizer and Swiss drugmaker Roche Holding are also racing to develop an easy-to-administer antiviral pill for COVID-19. Currently, only antibody cocktails that have to be given intravenously are approved for non-hospitalized patients.
The pill, which was originally developed to treat influenza, is designed to introduce errors into the genetic code of the virus, preventing it from spreading in the body.
Planned interim analysis of 775 patients in Merck’s study looked at hospitalizations or deaths. It was found that 7.3 percent of those given molnupiravir were hospitalized and none had died by 29 days after treatment, compared with hospitalization of 14.1 percent of placebo patients. There were also eight deaths in the placebo group.
The data was published in a press release and has not yet been peer-reviewed. Unlike most COVID-19 vaccines, which target the spike protein on the outside of the virus, the treatment works by targeting an enzyme the virus uses to make copies of itself.
“A safe, affordable, and effective oral antiviral would be a huge advance in the fight against COVID-19,” said Mr. Peter Horby, a professor of emerging infectious diseases at the University of Oxford.
In the trial, molnupiravir was taken every 12 hours for five days. The study enrolled patients with laboratory-confirmed mild-to-moderate COVID-19, who had symptoms for no more than five days. All patients had at least one risk factor associated with poor disease outcomes, such as obesity or older age. It said rates of adverse events were similar for both molnupiravir and placebo patients but did not reveal details.
Merck said viral sequencing done so far shows that the pill is effective against all variants of the coronavirus including the highly transmissible Delta. The drug is also being studied in a Phase III trial for preventing infection in people exposed to the coronavirus.
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