Pfizer has secured the US Food and Drug Administration (FDA) approval for Paxlovid (nirmatrelvir and ritonavir tablets), the company’s oral antiviral to treat adults with Covid-19.

The drug is indicated for the treatment of mild-to-moderate Covid-19 in adults, who are at elevated risk for progression to severe Covid-19, including hospitalisation or death.

Paxlovid is an oral SARS-CoV-2 main protease (Mpro) inhibitor therapy, prescribed early after infection to help prevent potential severe Covid-19 in adult patients.

It is generally administered at a standard dose containing 300mg (two 150 mg tablets) of nirmatrelvir with one 100mg tablet of ritonavir, given twice daily for five days.

The US Department of Health and Human Services has been offering Paxlovid in the US, since December 2021, under the FDA Emergency Use Authorisation (EUA).

Paxlovid will be available for adults, along with eligible children aged 12 to 18 years, who are not covered by the current approval, said the US FDA.

Pfizer chairman and CEO said: “Great advancements have been made in the fight against Covid-19, yet the virus remains a present and unpredictable concern.

“This is especially true for the hundreds of millions of American adults who are age 50 or older or are otherwise at high risk for progression to severe illness, even if symptoms are initially mild.

“Today marks a monumental milestone as Paxlovid became the first Covid-19 oral treatment to be approved by the US FDA, underscoring the value it brings to patients, providers, and health systems alike.”

The FDA approved Paxlovid based on the totality of scientific evidence shared by Pfizer, including safety and efficacy data from the EPIC clinical development programme.

It includes results from the Phase 2/3 EPIC-HR study, which enrolled unvaccinated, non-hospitalised adults with Covid-19, who were at increased risk of progressing to severe disease.

In the Phase 2/3 study, patients who initiated treatment with Paxlovid experienced an 86% reduction in risk of Covid-19-related hospitalisation or death, compared to placebo.

The drug also reduced Covid-19-related hospitalisations or death in a sub-group of non-hospitalised adults with confirmed Covid-19 who had at least one risk factor for progression.

Furthermore, recent real-world studies showed that Paxlovid is effective among both vaccinated and unvaccinated high-risk patients.