NEW YORK--An experimental antiviral pill developed by Merck & Co could halve the chances of dying or being hospitalized for those most at risk of contracting severe COVID-19, according to data that experts hailed as a potential breakthrough in how the virus is treated.
If it gets authorization, molnupiravir, which is designed to introduce errors into the genetic code of the virus, would be the first oral antiviral medication for COVID-19. Merck and partner Ridgeback Biotherapeutics said they plan to seek U.S. emergency use authorization for the pill as soon as possible and to make regulatory applications worldwide.
"An oral antiviral that can impact hospitalization risk to such a degree would be game-changing," said Amesh Adalja, senior scholar at the Johns Hopkins Center for Health Security.
Current treatment options include Gilead Sciences Inc's infused antiviral remdesivir and generic steroid dexamethasone, both of which are generally only given once a patient has already been hospitalized. "This is going to change the dialogue around how to manage COVID-19," Merck Chief Executive Robert Davis told Reuters.
Existing treatments are "cumbersome and logistically challenging to administer. A simple oral pill would be the opposite of that," Adalja added.
The results from the Phase III trial, which sent Merck shares up more than 9%, were so strong that the study is being stopped early at the recommendation of outside monitors. Shares of Atea Pharmaceuticals Inc, which is developing a similar COVID-19 treatment, were up more than 21% on the news.
Shares of COVID-19 vaccine Moderna Inc were off more than 10%, while Pfizer was down less than 1%. Jefferies analyst Michael Yee said investors believe "people will be less afraid of COVID and less inclined to get vaccines if there is a simple pill that can treat COVID."
Pfizer and Swiss drugmaker Roche Holding AG are also racing to develop an easy-to-administer antiviral for COVID-19. For now, only antibody cocktails that have to be given intravenously are approved for non-hospitalized patients.
White House COVID-19 response coordinator Jeff Zients said on Friday that molnupiravir is "a potential additional tool... to protect people from the worst outcomes of COVID," but added that vaccination "remains far and away, our best tool against COVID-19."
A planned interim analysis of 775 patients in Merck's study looked at hospitalizations or deaths among people at risk for severe disease. It found that 7.3% of those given molnupiravir twice a day for five days were hospitalized and none had died by 29 days after treatment. That compared with a hospitalization rate of 14.1% for placebo patients. There were also eight deaths in the placebo group.
"Antiviral treatments that can be taken at home to keep people with COVID-19 out of the hospital are critically needed,” Wendy Holman, Ridgeback's CEO, said in a statement.