Pfizer says its experimental antiviral pill for COVID-19 cut rates of hospitalisation and death by nearly 90 per cent in high-risk adults, as the drugmaker joined the race for an easy-to-use medication to treat the coronavirus.

Pfizer said it would ask the FDA and international regulators to authorise its pill as soon as possible, after independent experts recommended halting the company’s study based on the strength of its results.

Once Pfizer applies, the FDA could make a decision within weeks or months.

On Friday, Pfizer released preliminary results of its study of 775 adults

Patients who received the company’s drug along with another antiviral shortly after showing COVID symptoms had an 89 per cent reduction in their combined rate of hospitalisation or death after a month, compared to patients taking a dummy pill.

Fewer than 1 per cent of patients taking the drug needed to be hospitalised and none died.

In the comparison group, 7 per cent were hospitalised and there were seven deaths.

“We were hoping that we had something extraordinary, but it’s rare that you see great drugs come through with almost 90 per cent efficacy and 100 per cent protection for death,” said Mikael Dolsten, Pfizer’s chief scientific officer.

Study participants were unvaccinated, with mild-to-moderate COVID, and were considered high risk for hospitalisation due to health problems like obesity, diabetes or heart disease.

Treatment began within three to five days of initial symptoms, and lasted for five days.

Patients who received the drug earlier showed slightly better results, underscoring the need for speedy testing and treatment.

Pfizer reported few details on side effects but said rates of problems were similar between the groups at about 20 per cent.

Pfizer’s drug is part of a decades-old family of antiviral drugs known as protease inhibitors, which revolutionised the treatment of HIV and hepatitis C.

The drugs block a key enzyme viruses need to multiply in the human body.

The drug was first identified during the SARS outbreak originating in Asia in 2003.

Last year, company researchers decided to revive the medication and study it for COVID, given the similarities between the two coronaviruses.