SAN FRANCISCO (CBS SF/AP) — Pfizer’s Friday announcement that its experimental antiviral pill for COVID-19 cut rates of hospitalization and death by nearly 90% in high-risk adults could be a game changer in the treatment of the virus.

At least that was the initial opinion of UCSF Professor of Medicine and Infections Disease Dr. Monica Gandhi.

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“I was really amazed by how effective it was,” she told KPIX 5.

Pfizer said it will ask the FDA and international regulators to authorize 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.

“This game changing aspect of this, it’s an oral pill, it’s easy to give,” Gandhi said. “You just sent someone home with it like we send people with Tamiflu, with influenza, but this is even more effective.”

The pill, called Paxlovid and also known by the experimental name PF-07321332, is what’s known as a protease inhibitor. It’s designed to stop the virus from multiplying. Giving it along with ritonavir slows its breakdown in the body, the company said.

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Pfizer said 0.8% of patients who got the drug combination within three days were hospitalized within four weeks — three out of 389 patients — compared to 7% of patients who got placebos, or 27 out of 385. And seven of those who got placebos died, Pfizer said. No one who got the treatment died within a month.

Study participants were unvaccinated, with mild-to-moderate COVID-19, and were considered high risk for hospitalization due to health problems like obesity, diabetes or heart disease.

President Joe Biden said federal health officials were studying the results.

“We have already secured millions of doses and the therapy would be another tool in our toolbox to protect people from the worst outcomes of COVID,” he said.

Since the beginning of the pandemic last year, researchers worldwide have been racing to find a pill to treat COVID-19 that can be taken at home to ease symptoms, speed recovery and keep people out of the hospital.

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© Copyright 2021 CBS Broadcasting Inc. All Rights Reserved. KPIX 5 reporter Jocelyn Moran, The Associated Press and CNN contributed to this report.