Details about the study findings came from a Merck press release. In the planned interim analysis, Merck and Ridgeback evaluated data from 775 patients initially enrolled in the phase 3 MOVe-OUT trial.
All adults had lab-confirmed mild to moderate COVID-19, and reported onset of symptoms within 5 days of being randomly assigned to the drug or placebo. All had at least one risk factor linked with poor disease outcome (such as older age or obesity).
The drug is a ribonucleoside and works by creating mutations in the virus’s genome, halting the ability of the virus to replicate.
Through day 29 of the study, the drug reduced the risk or hospitalization or death by about 50%. While 7.3% of those who received the drug either died or were hospitalized by day 29, 14.1% of those on placebo did, a statistically significant difference (P = .0012).
Side effects were similar in both groups, with 35% of the drug-treated and 40% of the placebo group reporting some side effect, Merck reported. Adverse drug-related events were 12% in the drug group and 11% in the placebo group. While 1.3% of the drug-treated group quit the study because of an adverse event, 3.4% of the placebo group quit.
Pros, cons, and unknowns
The ability to take the drug orally, and at home, is a definite plus, Dr. Schaffner said, compared with the monoclonal antibody treatment currently approved that must be given intravenously or subcutaneously and in certain locations.
More people could be reached and helped with the option of an at-home, oral medicine, he and others agreed.
The regimen for molnupiravir is four pills, two times daily, for 5 days, even if symptoms are mild. As with other prescription drugs, “there will always be folks who don’t comply completely” with the prescribed regimen, Dr. Schaffner said. With this pill, that might be especially true if the symptoms are very mild.
The 50% reduction is not as effective as the benefit often quoted for monoclonal antibody treatment. In clinical trials of Regeneron’s monoclonal antibody treatment, the regimen reduced COVID-19–related hospitalization or death in high-risk patients by 70%.
Even so, the new pill could change the pandemic’s course, others say. “I think molnupiravir has the potential to change how we take care of people who have COVID and risk factors for developing severe disease,” Rajesh Tim Gandhi, MD, an infectious disease physician at Massachusetts General Hospital and Harvard Medical School in Boston, told this news organization.
“What we’ll need to do, however, is make sure that people get tested quickly after they develop symptoms and, if they’re confirmed to have COVID, start on the pills within 5 days of developing symptoms,” he said, while warning that more data are needed about the drug and the trial results.
Another concern is that the promise of a pill will stall vaccination rates, with some people figuring why get vaccinated when they can obtain the pill if they do get sick.
Relying on treatment alone won’t work, Dr. Schaffner said. “Let’s [also] focus on prevention, which is the vaccine. We have to keep working both sides of the street.”
Dr. Gandhi added: “It’s important to remember that even though molnupiravir reduced the likelihood of hospitalization and death, a number of people who received the drug still got sick enough to end up in the hospital.”
Also unknown, he said, is how severe their disease was and whether they will develop long COVID.
The Merck study included only unvaccinated people. Might it work for those vaccinated people who get a breakthrough infection? “From a purely scientific perspective, there is no reason to believe molnupiravir would not work in people who are vaccinated, but the overall efficacy on top of the vaccine is likely dependent on how well they were able to mount a protective immune response to the vaccine,” Ms. Moody said. Still, Merck believes the pill could be of benefit for these infections too, she added.
As for the expected cost, Ms. Moody said that the company takes into account a number of factors in setting pricing, “but fundamentally we look at the impact of the disease, the benefits that the drug delivers to patients and to society, and at supporting ongoing drug development.”