TolloTest™ is a diagnostic test that measures the 3CL protease from upper respiratory samples.
The 3CL protease is the main protease found in coronaviruses. It cleaves the coronavirus polyprotein at eleven conserved sites. It is a cysteine protease and a member of the PA clan of proteases. The 3CL protease is required for the replication of coronaviruses. Todos is using the 3CL protease biomarker as a new measure for viral load/contagiousness. This could provide clearer objective data to make end of quarantine decisions, when many PCR positive patients are likely inappropriately released from quarantine and able to infect others, or are inappropriately forced to quarantine due to continued positive PCR tests, when in fact they are no longer contagious due to the absence of 3CL protease. Todos is also using TolloTest as a surrogate marker to evaluate the ability of its COVID-19 antiviral 3CL protease inhibitor drug candidate Tollovir™ to reduce the SARS-CoV-2 virus.