Shionogi rises as much as 4.7%; FDA accepts ensitrelvir NDA

Shionogi rises as much as 4.7%; FDA accepts ensitrelvir NDA

Shionogi's stock rose by 4.7% on September 2, 2025, following the U.S. Food and Drug Administration's (FDA) acceptance of a New Drug Application (NDA) for ensitrelvir, an oral antiviral therapy for the prevention of COVID-19 following exposure to an infected individual. This development marks a significant milestone for Shionogi and the broader healthcare industry.

The FDA has set an action date of June 16, 2026, under the Prescription Drug User Fee Act (PDUFA). Ensitrelvir, an investigational oral antiviral, is the first and only oral therapy to meet the primary endpoint of preventing COVID-19 following exposure to an infected individual. The NDA is supported by results from the global, double-blind, randomized, placebo-controlled Phase 3 Study, SCORPIO-PEP, which studied ensitrelvir as post-exposure prophylaxis (PEP).

Shionogi, a Japanese pharmaceutical company, has a history of innovation in infectious disease treatment and prevention. Ensitrelvir is a SARS-CoV-2 main protease inhibitor, developed through joint research between Hokkaido University and Shionogi. It suppresses the replication of SARS-CoV-2 by selectively inhibiting the main protease.

Ensitrelvir received emergency regulatory approval in Japan in November 2022 and full approval in March 2024 for the treatment of COVID-19. It is currently under regulatory review in various countries, including the United States, Singapore, and Taiwan, for both post-exposure prophylaxis and treatment.

The acceptance of the NDA by the FDA is a significant step forward in the fight against COVID-19. It provides hope for a new tool to prevent the spread of the virus, particularly among those who may be exposed to infected individuals. Ensitrelvir's potential to stop viral replication early after exposure could help mitigate the risk of severe disease and long-term complications associated with COVID-19.

Shionogi's stock price increase reflects investor confidence in the company's ability to deliver on the promise of ensitrelvir. The drug's potential to protect people from COVID-19 following exposure is seen as a valuable addition to the existing arsenal of COVID-19 treatments.

As ensitrelvir moves through the regulatory process, it will be crucial to monitor its safety and efficacy data. The company has already demonstrated promising results in clinical trials, but further validation is necessary before the drug can be widely used.

In conclusion, the FDA's acceptance of Shionogi's NDA for ensitrelvir represents a significant advancement in the prevention of COVID-19. The stock price increase reflects the market's optimism about the potential benefits of this new therapy.

References:

[1] https://www.morningstar.com/news/business-wire/20250902536554/fda-accepts-shionogis-ensitrelvir-nda-as-the-first-oral-therapy-for-the-prevention-of-covid-19-following-exposure