The companies reported that molnupiravir showed a reduction in time to clear the virus; this was evaluated by the negativity of infectious virus isolation in nasopharyngeal swabs from participants with symptomatic SARS-CoV-2 infection. This secondary objective was determined by isolation in Vero cell line culture.

The phase IIA trial enrolled 202 nonhospitalized adults who had signs or symptoms of COVID-19 within seven days and confirmed active SARS-CoV-2 infection. The primary objective was reduction in time to viral negativity measured by reverse transcriptase polymerase chain reaction (RT-PCR) analysis of nasopharyngeal swabs.

Of the 182 participants with an evaluable nasopharyngeal swab, 42% showed detectable levels of cultured virus at baseline. The full study results remain blinded and will be shared at a later date when they become available, according to the companies. Additional phase II and phase II/III studies are underway.

Molnupiravir is an investigational, orally bioavailable form of a potent ribonucleoside analog that inhibits the replication of multiple RNA viruses including SARS-CoV-2. Molnupiravir was invented at Drug Innovations at Emory (DRIVE), a nonprofit biotechnology company that is wholly owned by Emory University.

Since licensed by Ridgeback, all funds used for the development of the antiviral by Ridgeback have been provided by Wayne and Wendy Holman (Ridgeback investors) and Merck.