TNX-3500 (sangivamycin) is a small molecule antiviral in development to treat COVID-19. It demonstrated broad-spectrum antiviral activity in laboratory-based assays against the coronaviruses SARS-CoV-2 and MERS-CoV. Sangivamycin also demonstrated that it acts as a dual target specific antiviral against filoviruses such as Ebola virus in cell culture infectivity studies. TNX-3500 was studied in the U.S. at the National Cancer Institute (NCI), part of NIH, as an investigational new drug for treating cancer in the 1960s. Studies at that time demonstrated safety in nonhuman primates and human adults when dosed daily or weekly. TNX-3500 was demonstrated in studies in mice to persist in tissues for greater than 12 days following a single dose. Its long half-life in tissues suggests that a single dose or weekly dosing may be sufficient for antiviral treatments.
Based on cell culture infectivity studies, TNX-3500 was 65 times more potent than remdesivir in inhibiting SARS-CoV-2. TNX-3500’s antiviral effect is additive when combined with remdesivir and reduces the amount of each drug necessary for an IC90. Combination therapies for other viruses have reduced the emergence of drug resistant viral strains.
TNX-3500 is an investigational new drug and has not been approved for any indication.