The US Food and Drug Administration (FDA) has granted Fast Track designation to Shionogi and Co Ltd’s investigational COVID-19 oral antiviral ensitrelvir (ensitrelvir fumaric acid). 

The FDA Fast Track designation is designed to facilitate the development and expedite the review of potential new therapies that treat serious conditions and fulfill an unmet medical need.

Ensitrelvir, known as Xocova 125 mg tablet in Japan, recently received emergency regulatory approval from the Ministry of Health, Labour, and Welfare for the treatment of SARS-CoV-2 infection. It remains an investigational drug outside Japan.

“There is a need for additional COVID-19 treatment options as SARS-CoV-2 continues to affect people in the US. Receiving Fast Track designation from the FDA recognizes the potential of ensitrelvir as a once-daily, oral antiviral for SARS-CoV-2,” says Nathan McCutcheon, CEO of Shionogi Inc, the US subsidiary of Shionogi, in a press release. “We look forward to our continued discussions with the FDA to bring ensitrelvir to patients as soon as possible.”

Ensitrelvir is an oral antiviral agent administered once daily for five days that suppresses the replication of SARS-CoV-2 by selectively inhibiting the viral 3CL protease. Shionogi recently presented results from the phase 3 part of the pivotal SCORPIO-SR trial (Phase 2/3 study) conducted in Japan, South Korea, and Vietnam at the Conference on Retroviruses and Opportunistic Infections. 

Several additional phase 3 clinical studies evaluating the safety and efficacy of oral antiviral ensitrelvir across a range of COVID-19 patient populations are planned and ongoing.