The US has its first and only oral COVID-19 post-exposure prophylaxis (PEP) on its way, after a Phase III trial of the drug ensitrelvir met goals required for approval by the US Food and Drug Administration (FDA).
Ensitrelvir, which will be sold under the brand name Xocova in the US, was developed by Japanese pharmaceutical company Shionogi. It's been approved for use in Japan since 2024.
As an anti–SARS-CoV-2 drug, ensitrelvir is designed to cut the risk of contracting the virus following exposure. The treatment is a five-day regimen of tablets, with three taken up front and then one pill each day for the remaining period.
“The FDA approval of Xocova provides an important new approach to preventing COVID-19, which continues to impact lives," said Frederick Hayden, MD, a medical professor at the University of Virginia School of Medicine, in a Shionogi statement. "COVID-19 can become severe, and even when mild or moderate, it can worsen or exacerbate chronic conditions or trigger new ones, including long COVID.
“Ensitrelvir inhibits viral replication, helping protect people who have been exposed to COVID-19 from developing illness," he added. "The PEP strategy has the potential to benefit anyone who does not want to get COVID-19. It could be useful not only in household settings but also in other exposure circumstances, such as outbreaks in nursing homes, chronic or acute care facilities and following travel-related exposures.”
In the SCORPIO-PREP Phase III trial,1,030 participants received ensitrelvir within 72 hours of household exposure to a symptomatic close contact, while 1,011 took a placebo.
Xocova reduced the risk of symptomatic COVID-19 by 67% following exposure to an infected individual through Day 10, compared with the control.
Side effects, most commonly headache, diarrhea and cough, were low – 15.1% in the ensitrelvir group and 15.5% in the placebo group – with the risk of serious adverse events extremely rare, at 0.2% for both cohorts.
Critically, none of the COVID-19 infections required hospitalizations.
“Xocova is the first and only oral option clinically proven to help prevent symptomatic COVID-19 after exposure among study participants regardless of vaccination status or baseline immunity from prior infection," said Nathan McCutcheon, President and CEO, Shionogi Inc. "With Xocova, people who are exposed to COVID-19 can act early to help protect themselves.”
While antiviral medications such as molnupiravir (brand name Lavegrio) have been available to reduce the severity of the virus in patients, ensitrelvir becomes the first drug on the market to help prevent infection.
Xocova will be available for all adults and individuals aged 12 years and older.
The results of the study were published in the New England Journal of Medicine.
Source: Shionogi
Fact-checked by Mike McRae
