Shionogi acquires Torii, FDA reviews COVID-19 prevention drug

Shionogi & Co. completed its acquisition of Torii Pharmaceutical Co. on September 1, 2025, following a tender offer and subsequent stock consolidation, making Torii Pharmaceutical a wholly-owned subsidiary. The transaction involved Shionogi acquiring 10,977,091 shares of Torii Pharmaceutical stock and then proceeding with a stock consolidation and a Treasury Share Acquisition, resulting in Shionogi holding 5 shares of Torii Pharmaceutical stock, representing 100.00% of voting rights after the Treasury Share Acquisition.

Separately, on September 3, 2025, Shionogi announced the U.S. FDA's acceptance for review of a New Drug Application (NDA) for ensitrelvir (Xocova®) as an oral antiviral for post-exposure prevention of COVID-19. The FDA has set a PDUFA action date of June 16, 2026. This application is based on positive results from the global, double-blind, randomized, placebo-controlled Phase 3 SCORPIO-PEP study. Ensitrelvir, already approved in Japan for COVID-19 treatment, would be the first and only oral therapy for post-exposure prevention if approved.