Merck and Ridgeback Say Their Covid-19 Pill Cuts Chance of Hospitalisation and Death by Half

Merck and Ridgeback Say Their Covid-19 Pill Cuts Chance of Hospitalisation and Death by Half
Two capsules of the experimental drug molnupiravir, co-developed by Merck and Ridgeback Biotherapeutics and originally discovered by scientists from Emory University. (Photo: Merck, Getty Images)

A pill that can effectively prevent the worst outcomes of covid-19 may finally be on the way.

On Friday, pharmaceutical companies Merck and Ridgeback Biotherapeutics announced the preliminary results of a large trial testing out their experimental antiviral drug, called molnupiravir. The drug reportedly reduced the odds of later hospitalisation or death by about 50% in high-risk individuals with mild to moderate illness — results so dramatically positive that the trial was stopped early. The companies now plan to seek an emergency use authorization for the drug, though the findings have yet to be vetted by outside scientists.

Molnupiravir is said to work by interfering with a virus’s ability to replicate inside a host’s cells, hopefully limiting viral load and enabling the immune system to clear the infection faster, without progressing to more severe illness. The drug had been in development prior to the pandemic as a potential treatment for the flu and other viral diseases.

The Phase 3 randomised, double-blinded, and controlled trial of molnupiravir, called MOVe-OUT, was intended to involve around 1,500 unvaccinated patients who initially had mild to moderate covid-19 symptoms but were at higher risk of severe illness due to their preexisting health. As is commonplace, though, researchers conducted an interim analysis of the trial when only 775 patients had been treated. About 14% of those on placebo went on to become hospitalized or die within 30 days, compared to around 7% of those who took molnupiravir, No deaths at all were reported in the treatment group, compared to eight who died in the placebo group.

Clinical trials can be stopped early by an independent board of outside scientists because the treatment looks so unlikely to work that it would be unethical to continue. But they can also be stopped because the treatment appears so much better than standard care that it wouldn’t be right to keep enrolling participants to a control or placebo group. And that’s what the independent board agreed was the case here. The companies say that more than 90% of the trial had already been recruited by the time it was formally ended, though, so there will likely be more data to sift through.

“With the virus continuing to circulate widely, and because therapeutic options currently available are infused and/or require access to a healthcare facility, antiviral treatments that can be taken at home to keep people with COVID-19 out of the hospital are critically needed,” said Wendy Holman, CEO of Ridgeback Biotherapeutics, in a statement announcing the results.

Though molnupiravir has shown promise as a covid-19 treatment for some time now, there has been some controversy and failure surrounding it as well.

Last year, federal official and eventual whistleblower Rick Bright alleged that the Trump administration retaliated against him for several decisions, including the reluctance by him and others to issue additional funding to the original founders of the drug at Emory University and later Ridgeback for their development of the drug, prior to and during the pandemic. Bright argued that the drug, while promising, was already getting enough resources, and he expressed concern that extra funding would subvert the normal process of research and development. He also noted that some animal studies had suggested that similar drugs could cause harmful mutations that could be passed onto to children.

In April, Merck and Ridgeback Biotherapeutics also stopped one part of their MOVe-OUT trial, after it was determined that not enough evidence supported the use of molnupiravir for already hospitalized patients. In fairness, this has been a common pattern for many antivirals tested out during the pandemic and is at least partially due to the fact that severe illness from covid-19 tends to be caused by a destructive immune response, not the infection itself by that point. Moreover, studies of molnupiravir don’t seem to have found evidence of the harmful side effects Bright was concerned about, at least so far. Drugs suspected of causing mutagenic side effects have been approved in the past, usually with caveats against their use by currently pregnant or planning to be pregnant people.

Merck and Ridgeback are now planning to immediately submit the drug for emergency use authorization. Following that, the Food and Drug Administration and affiliated experts will be expected to pore over the safety and trial data and heavily discuss the drug’s potential risks and benefits. Should the drug win authorization, it may not be alone for long — several other antiviral pills for early covid-19 treatment and prevention are reaching the end of their clinical trials as well. The generic antidepressant fluvoxamine has also been shown to significantly prevent hospitalisation from covid-19 in a large-scale but as yet not peer-reviewed trial.