In an announcement on Tuesday, Pfizer Inc. said that it is starting its Phase 1 Study of an oral drug to treat COVID-19.
The company said 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.” It also noted that while its candidate might be able to be used to treat COVID-19, it could also be used “to address future coronavirus threats.” The trial is being carried out in the United States.
The clinical candidate, PF-07321332, is a “protease inhibitor with potent anti-viral activity against SARS-CoV-2.” Protease inhibitors attach to a viral enzyme (named a protease) and prohibit the virus from replicating in a cell. The company’s statement adds that such inhibitors 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.”
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 statement from the company continues, “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.”
The company is also looking into the use of “an intravenously administered investigational protease inhibitor” which 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, said, “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 added, “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.”
Pfizer’s COVID-19 vaccine was the first vaccine to be authorized by the U.S. Food and Drug Administration, receiving emergency use authorization in December for people over the age of 16. The vaccine includes two doses, which are administered three weeks apart from one another. It was found to be 95% effective at preventing COVID-19 disease.
In October, the FDA approved the use of Veklury (remdesivir) for the treatment of COVID-19. It was the first drug to be approved to treat COVID-19 “for use in adults and pediatric patients 12 years of age and older and weighing at least 40 kg (about 88 pounds) requiring hospitalization.” The FDA had previously authorized the use of Veklury (remdesivir) with an emergency use authorization in May, which it later updated.