Is Remdesivir Effective Against New COVID-19 Variants?

This is part 2 of an interview with remdesivir investigator Mark Thrun, MD. Click here to watch part 1.

At this week’s 30th Conference on Retroviruses and Opportunistic Infections (CROI 2023), Contagion interviewed Mark Thrun, MD, an infectious disease specialist with Gilead Sciences and a lead investigator of several remdesivir studies.

Remdesivir (Veklury), the broad-spectrum antiviral, has become the standard-of-care for many hospitalized COVID-19 patients. However, when the only constant of the COVID-19 pandemic is change, can remdesivir remain effective against new and emerging variants?

“The SARS-CoV-2 virus mutates fairly readily,” Thrun acknowledged, “especially at sites in which it attaches to cells in the body.” Many COVID-19 therapeutics target this spike protein, but remdesivir targets the interior RNA dependent RNA polymerase (RdRp)of the virus, which is less susceptible to change.

“Remdesivir targets RdRp specifically, and so unlike other therapeutics…Remdesivir has remained effective against all the variants of concern so far,” said Thrun.

Thrun and fellow investigators are continuing to evaluate remdesivir to determine whether COVID-19 is undergoing any genetic changes that may predispose to resistance.

“We actually look in the lab, in in vitro studies, to determine ‘does remdesivir truly still treat this new variant?’” explained Thrun, “And indeed, throughout the course of the pandemic, that’s been the case.” Thrun noted his team presented additional data demonstrating the efficacy of remdesivir against the newer Omicron variants at CROI 2023.

“We don’t see the virus evolving away from being able to be combatted by remdesivir,” said Thrun.

Thrun noted that while COVID-19 patients admitted with severe illness may be able to benefit from remdesivir, the treatment works best when administered early. “We clearly know the earlier you treat the better,” said Thrun. “I think that’s a really big take-home message for all of us in health care, to educate patients that if they’re at risk for progressing, if they’re immunocompromised, if they’re older, that they should seek out care.”

“We’re tired of worrying about COVID, but there’s still a lot of COVID around,” said Thrun. “I would continue to encourage people that if they are symptomatic, that they should get tested, that there is an opportunity to get treated.”