Pfizer Inc. (New York, NY, USA) progresses to multiple ascending doses after completion of single ascending doses in a phase 1 study in healthy adults to assess the safety and tolerability of the investigative, new oral antiviral therapy drug for SARS-CoV-2, a virus that causes COVID-19.
Oral antiviral clinical candidate PF-07321332, a protease inhibitor of SARS-CoV2-3CL (external link), showed strong in vitro antiviral activity against SARS-CoV-2, as well as activity against other coronaviruses, suggesting potential for use in the treatment of COVID- 19, as well as potential use to address future coronavirus threats.
Protease inhibitors bind to a viral enzyme (called a protease), preventing the virus from replicating in the cell. Protease inhibitors have been effective in treating other viral pathogens such as HIV and hepatitis C virus, both alone and in combination with other antivirals. Currently available therapeutic products that target viral proteases are not usually associated with toxicity and as such, this class of molecules can potentially provide well-tolerated treatments against COVID-19.
A phase 1 trial was a randomized, double-blind, sponsored, placebo-controlled, escalation study of one or more doses in healthy adults evaluating the safety, tolerability, and pharmacokinetics of PF-07321332. The initiation of this study was supported by preclinical studies that demonstrated the antiviral activity of this potential first-class SARS-CoV-2 therapeutic agent specifically designed to inhibit SARS-CoV2 virus replication. Structure PF-07321332, along with preclinical data, will be shared at COVID-19 at the April 6 meeting of the American Chemical Society. Pfizer is also investigating an intravenously administered research protease inhibitor, PF-07304814, which is currently in a multi-dose phase 1b trial phase in hospitalized participants in a COVID-19 clinical trial.
“Resolving the COVID-19 pandemic requires both vaccine prevention and targeted treatment of those infected with the virus. Given the way in which SARS-CoV-2 mutates and the continued global impact of COVID-19, it seems likely that it will be crucial to have access to therapeutic options both now and outside the pandemic, ”said Dr. Mikael Dolsten., Chief Scientific Officer and President, Pfizer, World Research, Development and Medicine. “We designed PF-07321332 as a potential oral therapy that can be prescribed at the first signs of infection, without the need for patients to be hospitalized or in need of critical care. At the same time, Pfizer’s intravenous antiviral candidate is a potential new treatment option for hospitalized patients. Together, the two can create an end-to-end treatment paradigm that complements vaccination in cases where the disease still occurs. “