Vaccine Info

PF-07321332 Oral Antiviral

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Last reviewed
May 13, 2021

PF-07321332 Protease Inhibitor Antiviral Description

Pfizer's PF-07321332 is an oral antiviral therapeutic targeting the SARS-CoV-2 virus to prevent COVID-19. Pfizer's PF-07321332 is a protease inhibitor that has demonstrated potent in vitro antiviral activity against SARS-CoV-2 and activity against other coronaviruses, suggesting potential for use in the treatment of COVID-19, as well as potential use to address future coronavirus threats, says Pfizer.

By inhibiting the main protease, PF-07321332 prevents the virus from cleaving long protein chains into the parts it needs to reproduce itself.

Protease inhibitors bind to a viral enzyme (called a protease), preventing the virus from replicating in the cell. Protease inhibitors have effectively treated other viral pathogens such as HIV and hepatitis C virus, both alone and in combination with other antivirals. 

Pfizer is also investigating an intravenously administered investigational protease inhibitor, PF-07304814, which is currently in Phase 1b multi-dose trial in hospitalized clinical trial participants with COVID-19.

Mikael Dolsten, M.D., Ph.D., Chief Scientific Officer and President, Worldwide Research, Development, and Medical of Pfizer, commented in a press release issued on March 23, 2021, “We have designed PF-07321332 as a potential oral therapy that could be prescribed at the first sign of infection, without requiring that patients are hospitalized or in critical care. At the same time, Pfizer’s intravenous antiviral candidate is a potential novel treatment option for hospitalized patients. Together, the two have the potential to create an end to end treatment paradigm that complements vaccination in cases where the disease still occurs.”

Chemical Formula: C23H32F3N5O4 To learn more, please visit

PF-07321332 Protease Inhibitor Antiviral Indication

PF-07321332 Antiviral Therapeutic is indicated to prevent the SARS-CoV-2 from replicating in human host cells. If successful, PF-07321332 can be prescribed to patients before they require hospitalization.

PF-07321332 Protease Inhibitor Antiviral News

May 4, 2021 - Pfizer Inc. published today its 'Key Near-term Potential Milestones for COVID-19 Vaccine Program (2021)' on slide #8 within its financial report.

March 23, 2021 - Pfizer Inc. announced that it is progressing to multiple ascending doses after completing the dosing of single ascending doses in a Phase 1 study in healthy adults to evaluate the safety and tolerability of an investigational, novel oral antiviral therapy for SARS-CoV-2, the virus that causes COVID-19. This Phase 1 trial is being conducted in the United States.

PF-07321332 Protease Inhibitor Antiviral Clinical Trial

A Phase 1, double-blind, sponsor open, single, and multiple ascending dose study evaluates the safety, tolerability, and pharmacokinetics of PF-07321332 in healthy participants.

Clinical Trials

No clinical trials found