WASHINGTON — Drugmaker Merck said Friday that its experimental COVID-19 pill reduced hospitalizations and deaths by half in people recently infected with the coronavirus and that it would soon ask health officials in the U.S. and around the world to authorize its use.

If cleared, the drug would be the first pill shown to treat COVID-19, a potentially major step forward in global efforts to control the pandemic. All COVID-19 therapies now authorized in the U.S. require an IV or injection.

A pill that could be taken at home, by contrast, could keep many patients out of the hospital, easing the workload on strained health care professionals. It could also help curb outbreaks in lower-income countries that don't have access to the more expensive infusion therapies.

Merck and its partner Ridgeback Biotherapeutics said early results showed patients who received the drug, called molnupiravir, within five days of COVID-19 symptoms had about half the rate of hospitalization and death as patients who received a dummy pill. The study tracked 775 adults with mild-to-moderate COVID-19 who were considered higher risk for severe disease due to health problems such as obesity, diabetes or heart disease. The results have not been peer reviewed by outside experts, the usual procedure for vetting new medical research.

Among patients taking molnupiravir, 7.3% were either hospitalized 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 time period compared with eight deaths in the placebo group, according to Merck.

An independent group of medical experts monitoring the trial recommended stopping it early because the interim results were so strong. That is typical when early results show so clearly that a treatment works that there is no need for further testing before applying for authorization. Company executives said they plan to submit the data for review by the Food and Drug Administration in coming days. 

Once the submission is complete, the FDA could make a decision within weeks — and, if OK'd, the drug could be on the market soon after. Merck only studied its drug in people who were not vaccinated. But FDA regulators may consider authorizing it for broader use in vaccinated patients who get COVID-19 symptoms.

"It exceeded what I thought the drug might be able to do in this clinical trial," said Dr. Dean Li, vice president of Merck Research Laboratories. "When you see a 50% reduction in hospitalization or death that's a substantial clinical impact."

Patients take eight pills per day for five days. Side effects were reported by both groups in the Merck trial, but they were slightly more common among the group that received a dummy pill. The company did not specify the problems. 

Earlier study results showed the drug did not benefit patients who were already hospitalized with severe disease.

The U.S. has approved one antiviral drug, remdesivir, specifically for COVID-19, and allowed emergency use of three antibody therapies that help the immune system fight the virus. But all the drugs have to given by IV or injection at hospitals or medical clinics, and supplies have been stretched by the latest surge of the delta variant. 

Health experts including the top U.S. infectious disease expert Dr. Anthony Fauci have long called for a convenient pill that patients could take when COVID-19 symptoms first appear, much the way the standard flu medication Tamiflu helps fight influenza. Such medications are seen as key to controlling future waves of infection and reducing the impact of the pandemic.

Vaccines remain the most effective way of protecting against COVID-19, but effective drugs are critical given that billions of people around the world remain unvaccinated.

Merck's pill works by interfering with the coronavirus's ability to copy its genetic code and reproduce itself. It has shown similar activity against other viruses.

The U.S. government has committed to purchase 1.7 million doses of the drug if it is authorized by the FDA. Merck has said it can produce 10 million doses by the end of the year and has contracts with governments worldwide. The company has not announced prices.

Several other companies, including Pfizer and Roche, are studying similar drugs that could report results in the coming weeks and months. 

Merck had planned to enroll more than 1,500 patients in its late-stage trial before the independent board stopped it early. The results reported Friday included patients enrolled across Latin America, Europe and Africa. Executives estimated about 10% of patients studied were from the U.S.