Warning for molnupiravir despite green-light from drug regulators

By Maryanne Demasi, PhD

Last October, I investigated the hype over a new antiviral drug called molnupiravir (branded Lagevrio), developed by Ridgeback Biotherapeutics and Merck Sharp & Dohme (MSD). 

It was touted to be the next blockbuster drug -- the first authorised oral pill for the treatment of COVID-19. But now, new data suggest the drug company exaggerated the benefits and underplayed the harms.

At the time, it was only “interim data” from a phase III trial called MOVe-OUT. In a press release published by MSD, the company claimed the drug could reduce hospitalisations and death by 50% in people with mild to moderate COVID-19 illness. 

Despite the paucity of data, the manufacturer managed to secure lucrative deals with major international governments pending approval by drug regulators.

The UK regulator was the first to grant “conditional marketing approval” for molnupiravir, with Health Secretary Sajid Javid publicly boasting it was an “historic day” for his country, and that the drug would be a “game-changer” and “ground-breaking.”

This was all before the completion of the trial. In the weeks that followed, American, Japanese, and Australian drug regulators, all gave their stamp of approval after the phase III trial was complete. 

In Australia for example, GPs may now prescribe molnupiravir for COVID-positive adults at high risk of developing severe disease, and the cost is largely subsidised by the government.

But not everyone is enamoured with the drug. France cancelled its order and there are now reports that Merck is struggling to win approval in Europe and Canada, because the data are proving to be “problematic” according to those familiar with the process.

As more data emerges, some experts warn against the use of molnupiravir, citing concerns over the drug’s clinical value and its safety.