This past Tuesday, Pfizer Inc. released an announcement that it is beginning its Phase 1 Study of an oral drug to treat Covid-19.
In the announcement, the company stated that the study is being conducted in order “to evaluate the safety and tolerability of an investigational, novel oral antiviral therapeutic for SARS-CoV-2, the virus that causes COVID-19.” Pfizer also stated that in addition to the fact that its candidate might be able to treat COVID-19, it could also be used “to address future coronavirus threats.” Pfizer plans to carry out the trials of its candidate in the United States.
The candidate of the trial, PF-07321332, is a “protease inhibitor with potent anti-viral activity against SARS-CoV-2.” the way protease inhibitors work is that they attach to a viral enzyme, the protease) and stop the virus from replicating inside cells. The company’s announcement also states that inhibitors such as this have been successful in the past “at treating other viral pathogens such as HIV and hepatitis C virus, both alone and in combination with other antivirals.”
Pfizer has said that the Phase 1 trial is “a randomized, double-blind, sponsor-open, placebo-controlled, single- and multiple-dose escalation study in healthy adults” that will evaluate “the safety, tolerability and pharmacokinetics” of the oral candidate.
The announcement from the company also states that “initiation of this study is supported by preclinical studies that demonstrated the antiviral activity of this potential first-in-class SARS-CoV-2 therapeutic designed specifically to inhibit replication of the SARS-CoV2 virus. The structure of [the candidate], together with the pre-clinical data, will be shared in a COVID-19 session of the Spring American Chemical Society meeting on April 6.”
Pfizer has also stated that it is looking into the use of “an intravenously administered investigational protease inhibitor.” This is currently being used in a trial with hospitalized clinical trial participants who have COVID-19.
Mikael Dolsten, MD, PhD., Chief Scientific Officer and President, Worldwide Research, Development and Medical of Pfizer, stated, “Tackling the COVID-19 pandemic requires both prevention via vaccine and targeted treatment for those who contract the virus. Given the way that SARS-CoV-2 is mutating and the continued global impact of COVID-19, it appears likely that it will be critical to have access to therapeutic options both now and beyond the pandemic.”
Dolsten continued, “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 disease still occurs.”
As we know, Pfizer had the first vaccine for COVID-19 to be authorized by the U.S. Food and Drug Administration. It received emergency use authorization this past December for people over 16 and was found to be ~95% effective at preventing COVID-19.