Pharmaceutical company Romark disclosed on Tuesday the start of a Phase 3 clinical trial of its investigational new drug candidate NT-300 (nitazoxanide extended-release tablets) for the treatment for mild or moderate COVID-19.

Under a multicentre, randomized, double-blind trial, the company said it will enroll up to 800 people 12 years and older with fever and respiratory symptoms consistent with COVID-19. These participants will be given either NT-300 or placebo twice daily for five days. The primary endpoint is a reduction in the time to sustained response (a measure of recovery time) compared with placebo.

In cell cultures, the active ingredient in NT-300, nitazoxanide, inhibits replication of a broad range of respiratory viruses, including the SARS-CoV-2 virus that causes COVID-19. Nitazoxanide has also been shown to inhibit replication of SARS, MERS and other coronaviruses as well as influenza viruses, rhinoviruses, parainfluenza viruses, RSV in cell culture studies, stated the company.

The oral NT-300 tablets are designed to deliver antiviral concentrations of drug to the respiratory tract throughout twice-daily dosing. The 600 mg dose was selected based upon a dose-range-finding clinical trial conducted in outpatients with influenza, Romark concluded.