Merck Covid antiviral pill did not lower risk of hospitalization, study found

Merck’s Covid-19 antiviral pill has failed to show it can reduce the risk of hospitalization and death in adults at higher risk of the disease, according to results from a pivotal UK clinical trial.

Preliminary results released Thursday from a study of more than 25,000 people show that taking molnupiravir – a key treatment for Covid – can shorten a patient’s recovery time. However, the drug showed no benefit compared to taking a placebo in terms of reducing hospitalizations, one of the key measures regulators use to recommend antiviral treatments.

Chris Butler, Professor of Primary Care at Oxford University and lead investigator for the studystopped calling it a failure but said there was “no difference” between taking the drug or a placebo in the context of low hospitalization during the Omicron wave of Covid-19.

Omicron has been shown to be less severe than previously circulating variants. Butler stressed that the results are preliminary and that further analysis would allow regulators to make decisions about the drug’s use.

Some health experts said the results cast further doubts on the effectiveness of molnupiravir, a treatment costing nearly $5 billion.

Merck’s Lagevrio-branded drug raised hopes and sent the company’s shares higher last year after early data from a late-stage study suggested it halved the risk of death and hospitalization. However, subsequent analysis revealed that its effectiveness, at 30 percent, was lower than previously thought.

dr Andrew Hill, senior visiting research fellow at the University of Liverpool, said the failure to meet a target of reducing hospitalizations or deaths raises questions, especially as the UK study is the largest ever for a Covid-19 treatment was carried out.

“If molnupiravir doesn’t show any benefit, it will be difficult for health authorities to justify the $5.5 billion that has been spent on this drug worldwide to date,” he said.

“We’ve seen this situation before with other Covid-19 drugs like remdesivir. Initial results looked encouraging, but then larger studies showed no benefit.”

The UK study has been cited as important evidence for approval of molnupiravir in the European Union. But the bloc’s drug regulator, the European Medicines Agency, has stalled its review over concerns about its effectiveness, the Financial Times reported earlier this year.

One person with knowledge of the regulator’s mindset said it was difficult to assess whether the drug was having a significant effect. “Unfortunately, it’s difficult to say much about molnupiravir other than that it doesn’t appear to affect molnupiravir [disease] progression.”

The EMA hasn’t approved it yet.

The UK regulator, the Medicines and Healthcare Products Regulatory Agency, has given limited approval for the drug. The US Food and Drug Administration has approved molnupiravir but restricted its use. Most regulators have said it should be used as a second- or third-line drug for the disease.

Merck said the study provided important results and underscored the value of Lagevrio in this evolving pandemic, where vaccination rates are higher and the Omicron variant causes less serious illness, including fewer hospitalizations and deaths.