The double-blind, placebo-controlled trial is designed to evaluate the safety, tolerability, and pharmacokinetics of the candidate.

In preliminary preclinical studies conducted by New York University (NYU) Grossman School of Medicine and Pfizer, the drug was shown to block the action of the main protease, which is necessary for the replication of SARS-CoV-2. In one set of cell culture experiments, the candidate was found to be 3.3 times more potent a blocker of replication compared to remdesivir, the only antiviral drug authorized for emergency use against COVID-19.

A study posted to bioRxiv evaluating the candidate in 3D airway model cells demonstrated that it is effective at lower concentrations than other drugs targeting the main protease that are currently under development.

Pfizer designed, manufactured, and supplied PF-00835231 for the preclinical experiments. NYU Langone researchers performed the study experiments, building on their extensive research with influenza to design one of the first airway cell culture model systems for the study of SARS-CoV-2.