A highly anticipated study of Pfizer’s Covid pill confirmed that it helps stave off severe disease, the company announced on Tuesday.

Pfizer also said its anti-viral pill worked in laboratory studies against the omicron variant, which is surging in South Africa and Europe and is expected to dominate US cases in the weeks ahead.

“We are confident that, if authorised or approved, this potential treatment could be a critical tool to help quell the pandemic,” Albert Bourla, Pfizer’s chief executive, said in a statement.

Last month, Pfizer asked the Food and Drug Administration to authorise the pill, known as Paxlovid, based on a preliminary batch of data. The new results will undoubtedly strengthen the company’s application, which could mean that Americans infected with the virus may have access to the pill within weeks.

In Tuesday’s announcement, Pfizer said that if given within three days of the onset of symptoms, Paxlovid reduced the risk of hospitalisation and death by 89 per cent. If given within five days, the risk was reduced almost as much, to 88 per cent.

The results, based on an analysis of 2,246 unvaccinated volunteers at high risk of severe disease, largely match the company’s initial, smaller analysis of the clinical trial, released last month.

Pfizer said that 0.7 per cent of patients who received Paxlovid were hospitalised within 28 days of entering the trial, and none died. By contrast, 6.5 per cent of patients who received a placebo were hospitalised or died.

Pfizer also released preliminary data from a separate trial looking at people with a lower risk. These volunteers including vaccinated people who carried a risk factor for severe disease, as well as unvaccinated patients with no risk factors.

Among this group of 662 volunteers, Paxlovid reduced the risk of hospitalisation and death by 70 per cent, the company said. Mikael Dolsten, the chief scientific officer of Pfizer, was exuberant about the results after having overseen the development of the drug since the spring of 2020, with more than 200 company scientists crafting the molecule and then testing it in animals and people.

While the drug was in development, Dr Dolsten held out hope that it might be 60 per cent effective. Its true potency left him stunned. _“We really hit the top of the board,” he said in an interview.

In both trials, most of the volunteers were infected with the Delta variant. But Pfizer said on Tuesday that in laboratory experiments, Paxlovid also performed well against the highly mutated Omicron variant. The drug jams into one of Omicron’s key proteins — called a protease — just as effectively as it does with other variants, Pfizer found.

New York Times News Service