Deena Bearsley

(Reuters). – An experiment in Pfizer Inc (NYSE:), announced Friday that it had stopped its experimental antiviral medication for COVID-19. The drug reduced by 89% the chance of dying or being hospitalized for those at highest risk.

The results appear to surpass those seen with Merck & Co Inc’s pill molnupiravir, which was shown last month to halve the likelihood of dying or being hospitalized for COVID-19 patients also at high risk of serious illness.

Both companies do not have full trial data.

Pfizer stated it will submit interim results from its drug combination, called Ritonavir-based, to the U.S. Food and Drug Administration in the context of an emergency application that it launched in October.

Paxlovid will be the name of this combination treatment. It consists three tablets that are taken twice daily.

Pfizer planned to analyze 1,219 COVID-19 patients. It looked at deaths and hospitalizations among those with moderate or severe COVID-19.

The study found that only 0.8% of patients who received Pfizer’s medication within the first three days of symptoms onset were admitted to hospital and no one had died before 28 days. This compares to the 7% hospitalization rate for placebo patients. Seven deaths were reported in the placebo-treated group.

The rates of patients who were treated within the first five days after symptoms began were comparable to the 6.7% hospitalization rate for the placebo, which had 10 deaths.

To be effective, antivirals must be administered as soon as possible to prevent infection from taking hold. Merck had its drug tested five days before symptoms arose.

Annaliesa Anderson of Pfizer, who is the head of its program, stated that they had high efficacy even though patients were treated five days later. “People might need to wait a while before receiving a test, or anything. But this shows that people have enough time to get treatment and actually provide a health benefit,” Anderson said.

Side effects of treatment were not disclosed by the company. However, adverse events have been reported in around 20% of treatment- and placebo-treated patients.

“These data suggest that our oral antiviral candidate, if approved by regulatory authorities, has the potential to save patients’ lives, reduce the severity of COVID-19 infections, and eliminate up to nine out of ten hospitalizations,” Pfizer Chief Executive Albert Bourla said in a statement.

Experts on infectious disease stress that COVID-19 prevention through widespread use of vaccines will be the best method to manage the outbreak. But only 58% Americans have been fully vaccinated, and there is very little access in other parts of the country.

Pfizer’s protease inhibitor, a drug that is part of a group known as protease inhibitors, works to prevent the coronavirus from multiplying.

Merck’s Molnupiravir uses a new mechanism to infuse errors into the virus’ genetic code. Merck sold the medication to millions, and it was also approved by U.K. regulators this week.

Britain announced earlier this month that 250,000 Pfizer Antivirals had been purchased.

Pfizer also studies whether the pill can be taken by individuals without serious COVID-19 risk factors, as well as to protect against coronavirus infections in those who are already exposed.