Clinical Development Program for NT-300 Includes Trials Addressing Prevention and Treatment of COVID-19 and Other Viral Respiratory Illnesses


TAMPA, Fla. – April 27, 2020 – Romark announced today it will initiate two clinical trials of its investigational new drug candidate NT-300 (nitazoxanide extended-release tablets) for prevention of COVID-19 and other viral respiratory illnesses in high-risk populations, including elderly residents of long-term care facilities and healthcare workers.

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-19.1-4 Nitazoxanide has also been shown to inhibit replication of SARS, MERS and other coronaviruses as well as influenza viruses, rhinoviruses, parainfluenza viruses, RSV and other respiratory viruses in cell culture studies.2-4 The broad-spectrum antiviral activity of nitazoxanide is attributed to its interference with human cellular pathways that the virus exploits to replicate, rather than to a virus-targeted mechanism.2,4


“These new clinical trials we have initiated aim to investigate the safety and efficacy of NT-300 in preventing viral respiratory infections, with particular emphasis on COVID-19,” said Jean-François Rossignol, M.D., Ph.D., Chief Medical and Scientific Officer of Romark. “Prevention is an important strategy in controlling infectious diseases and could be especially important in the context of the ongoing COVID-19 pandemic. The ability of NT-300 to thwart infection of human cells by viruses supports an investigation for its use early in the course of infection to prevent disease. We look forward to learning more about its potential for managing COVID-19 and other serious viral illnesses.”


The first trial is designed to enroll 800 elderly residents of long-term care facilities following reports of the first case of COVID-19 at the sites. The second will enroll 800 healthcare workers who are at risk of exposure to the SARS-CoV-2 coronavirus. In both studies, participants will receive either NT-300 or placebo for six weeks, and the primary endpoint is the rate of COVID-19 illness for NT-300 versus placebo.


In addition to these prevention studies, Romark plans to conduct a third clinical trial of NT-300 for the early treatment of COVID-19 and other viral respiratory illnesses.


Romark has been studying the potential of NT-300 in emerging and drug-resistant viruses for nearly a decade, and its development program has been supported by the U.S. Department of Health and Human Services.


The only drugs approved for treating viral respiratory illnesses are direct-acting antiviral drugs such as oseltamivir (Tamiflu®) for treating and preventing influenza, and these drugs can be associated with problems of resistance. There are no approved treatments for other viral respiratory illnesses caused by rhinoviruses, enteroviruses, coronaviruses, parainfluenza viruses, respiratory syncytial viruses (RSV), human metapneumovirus or bocavirus.  


About Nitazoxanide

Nitazoxanide, the active ingredient of NT-300, was originally developed for treating intestinal protozoan infections caused by Cryptosporidium parvum and Giardia lamblia. Laboratory studies demonstrating broad-spectrum antiviral activity led to the development of nitazoxanide as a broad-spectrum, host-directed antiviral drug.

Laboratory studies to evaluate the potential for resistance of influenza A virus to tizoxanide have been unable to select for resistant viruses, suggesting a low potential for viral resistance. Other studies have shown tizoxanide suppresses secretion of pro-inflammatory cytokines that are upregulated by viral respiratory infections including IL-6.5 The antiviral and anti-cytokine activities of nitazoxanide are attributed to modulation of mitochondrial function and consequential effects on cell signaling pathways.


About NT-300

NT-300 (nitazoxanide extended-release tablets) is an investigational broad-spectrum antiviral drug undergoing Phase 3 clinical development for treating and preventing acute respiratory illnesses caused by a broad range of seasonal, emerging or drug-resistant respiratory viruses, including influenza viruses, rhinoviruses, other enteroviruses, coronaviruses, parainfluenza viruses, respiratory syncytial viruses (RSV), human metapneumovirus or bocavirus.


The NT-300 tablets, administered orally, 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.6 To date, clinical trials of NT-300 for treatment of viral respiratory illnesses have included more than 5,000 patients. The NT-300 clinical development program has been designed to provide robust evidence of effectiveness to support use of NT-300 and to ensure maximum benefit to the very large number of patients that experience these illnesses.


About Romark

Romark is a vertically-integrated, research-based pharmaceutical company focused on the discovery, development and delivery of innovative new medicines, primarily in the field of infectious diseases.  Romark has operations in the United States, Puerto Rico and Europe, and it conducts research and development and commercializes its products globally.


Romark is a leader in developing new drugs for treating a broad range of seasonal, emerging and drug-resistant viral respiratory illnesses. It is also developing a new product aimed at inducing functional cure of chronic hepatitis B. Products discovered, developed and commercialized by Romark have been used to positively impact the lives of more than 400 million people worldwide.



  1. Wang M, Cao R, Zhang L, et al. Remdesivir and chloroquine effectively inhibit the recently emerged novel coronavirus (2019-nCoV) in vitro. Cell Res 2020; 0:1-3.
  2. Rossignol JF. Nitazoxanide: A first-in-class broad-spectrum antiviral agent. Antivir Res 2014; 110:94-103.
  3. Cao J, Forrest JC, Zhang X. A screen of NIH Clinical Collection small molecule library identifies potential anti-coronavirus drugs. Antivir Res 2015; 114:1-10.
  4. Rossignol JF. Nitazoxanide, a new drug candidate for the treatment of Middle East respiratory syndrome coronavirus. J Infect Public Health 2016; 9:227-230.
  5. Hong SK, Kim HG, Chong CS, Choi IS, Lee JB, Park SY. Nitazoxanide suppresses IL-6 production in LPS-stimulated mouse macrophages and TG-injected mice. Int Immunopharmacol 2012; 13:23-7.
  6. Haffizula J, Hartman A, Hoppers M, et al. A randomized, double-blind, placebo controlled clinical trial of nitazoxanide in adults and adolescents with acute uncomplicated influenza. Lancet Infect Dis 2014; 14:609-618.

Development of NT-300 has been supported by the U.S. Department of Health and Human Services (HHS)/Office of the Assistant Secretary of Preparedness and Response (ASPR)/Biomedical Advanced Research and Development Authority (BARDA) under contract HHSO100201300004C.


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