News that an experimental antiviral drug from Merck appears to halve the risk of hospitalization or death from Covid-19 has bolstered hopes of finding a simple at-home treatment for the virus.
The drug, molnupiravir, is given as a pill. It performed well enough in a late-stage clinical trial of adults at high risk of severe Covid-19 that the independent review board overseeing the study recommended that it be ended early. Now Merck and its partner Ridgeback Biotherapeutics will seek FDA authorization for the drug “as soon as possible,” they said Friday.
If those promising preliminary results hold, the new drug could help fill a significant gap in the world’s Covid-19 arsenal. As the pandemic nears the end of its second year, there are still only a handful of treatments for Covid-19 — and none that people can take at home. Finding a drug that can minimize the risk of severe illness could ease the burden on the country’s hospitals and blunt future surges of infection, in combination with vaccines and public health measures like mask-wearing.
Currently, “very few treatment options [are] available,” said Matthew Hall, a biologist at the National Institutes of Health’s National Center for Advancing Translational Sciences. “Someone can go to an infusion center and be infused with a neutralizing antibody, but [there’s] nothing in a pill form that’s able to just be prescribed to take in early in an infection to reduce the severity of symptoms and the extent of symptoms.”
At a press conference Friday, the president’s chief medical adviser, Anthony Fauci, called the trial results “impressive” and “very good news.” Fauci said that Merck had briefed government health officials last night on the trial data.
All 775 participants included in Merck’s interim analysis had tested positive for mild or moderate Covid-19 within five days of joining the study. And all study participants were unvaccinated and had at least one condition that increased their risk of developing severe Covid-19 — such as being older than 60, obese or having diabetes or heart disease.
Just over 7 percent of patients who received the drug, which is taken twice a day for five days, had been hospitalized through the 29th day of the study. Roughly 14 percent in the placebo group were hospitalized or died, Merck said.
No deaths were reported in patients given molnupiravir during that time, but eight people given the placebo died. Side effects were mild.
Merck did not say which groups would be covered by its authorization request. The global study examined unvaccinated adults at high risk of severe illness and death, rather than the broader adult population.
While much of the attention early in the pandemic focused on vaccine development, the quest for drugs to treat Covid-19 has gained steam in recent months. The Biden administration has channeled billions of dollars into finding new therapies, seeing them as crucial to help end the pandemic.
“Having an effective treatment for Covid-19 in a pill form would have a significant positive impact on this pandemic,” said Molly Howell, the immunization program manager for the North Dakota Department of Health.
Vaccines are powerful at preventing infection but cannot treat the disease. The only Covid antiviral drug available now, Gilead Sciences’ remdesivir, must be given as an infusion in a clinical setting, and evidence for its effectiveness is mixed. And although monoclonal antibodies are more effective than molnupiravir at reducing the risk of hospitalization and death, they are expensive and hard to make and can only be given via infusion or injection.
Other available treatments, like the steroid dexamethasone, can reduce the risk of death in severely ill patients, but are not effective in people with mild or moderate Covid.
“We want to manage patients outside the hospital,” said Raymund Razonable, an infectious disease specialist at the Mayo Clinic in Rochester, Minn. “We don’t want patients to develop severe illness.”
The relatively rapid development of molnupiravir for Covid-19 is due to “easily over a decade of work that had gone into this molecule for other viruses beforehand,” said Hall.
The NIH’s Antiviral Program for Pandemics aims to ferry more antiviral drug candidates through the development pipeline in anticipation of future infectious-disease threats.
The goal, Hall said, “is to make drug candidates now.” That way, “this short timeline can unfold when a new pathogen emerges, rather than what is on average 15 years and billions of dollars per drug. We obviously don’t want to operate on those timelines.
He said that ideally, molnupiravir would be given to anyone who tests positive for Covid-19 in the first few days after diagnosis. “It should, irrespective of their vaccination status and things like that, it should reduce the length of symptoms,” he said.
Merck expects to produce 10 million treatment courses of molnupiravir by the end of 2021. It has also licensed the drug to five Indian manufacturers to produce doses for India and more than 100 low- and middle-income countries. The company said it will offer tiered pricing based on a nation’s ability to pay.
The U.S. government agreed earlier this year to purchase 1.7 million treatment courses of the drug pending FDA authorization, at a cost of $1.2 billion.
Jeffrey Zients, the White House Covid-19 coordinator, said Friday that the government has options to purchase additional doses. He also cautioned that any antiviral would not supplant the need to vaccinate as many Americans as possible. “If approved, this is an additional tool in our toolbox, but it is really important to remember that vaccination remains our best tool.”
“It is always better to prevent infection than to treat infection,” said Howell. “Vaccinations and treatment are not mutually exclusive and in combination are the way to control the pandemic.”
Merck plans to publish the data from the clinical trial, which has not undergone peer review, in a scientific journal. The company will also seek authorization or approval from regulatory agencies outside the United States.
David Lim contributed to this report.