Merck and its partner Ridgeback Biotherapeutics announced that its experimental Covid-19 pill molnupiravir reduced hospitalisation and deaths by half in people recently infected with the coronavirus and that it would soon ask health officials in the US and around the world to authorize its use.

If cleared, Merck's drug would be the first pill shown to treat Covid-19, a potentially major advance in efforts to fight the pandemic. All Covid-19 therapies now authorised in the US require an IV or injection.

Early results showed patients who received molnupiravir, within five days of Covid-19 symptoms had about half the rate of hospitalisation and death as patients who received a dummy pill.

The study tracked 775 adults with mild-to-moderate Covid-19 who were considered at higher risk for severe disease due to health problems such as obesity, diabetes or heart disease.

Among patients taking molnupiravir, 7.3 per cent were either hospitalised or died at the end of 30 days, compared with 14.1% of those getting the dummy pill. There were no deaths in the drug group after that period compared with eight deaths in the placebo group. The results were released by the company and have not been peer-reviewed.

An independent group of medical experts monitoring the trial recommended stopping it early because the interim results were strong. Company executives said they are in discussions with the U.S. Food and Drug Administration and plan to submit the data for review in the coming days.

“More tools and treatments are urgently needed to fight the Covid-19 pandemic, which has become a leading cause of death and continues to profoundly affect patients, families, and societies and strain health care systems all around the world. With these compelling results, we are optimistic that molnupiravir can become an important medicine as part of the global effort to fight the pandemic and will add to Merck’s unique legacy of bringing forward breakthroughs in infectious diseases when they are needed most. Consistent with Merck’s unwavering commitment to save and improve lives, we will continue to work with regulatory agencies on our applications and do everything we can to bring molnupiravir to patients as quickly as possible,” said Robert M. Davis, chief executive officer and president, Merck.

“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, chief executive officer of Ridgeback Biotherapeutics. “We are very encouraged by the results from the interim analysis and hope molnupiravir, if authorized for use, can make a profound impact in controlling the pandemic. Our partnership with Merck is critical to ensuring rapid global access if this medicine is approved, and we appreciate the collaborative effort to reach this important stage of development.”