Merck agreed to acquire Cidara Therapeutics for about $9.2 billion to add CD388, a long‑acting neuraminidase inhibitor–Fc conjugate, to its antiviral portfolio. CD388 is in Phase III (ANCHOR) as a single‑dose prevention candidate for high‑risk people; Cidara reported positive Phase IIb NAVIGATE results showing 58–76% prevention efficacy across dose groups. Merck cited confidence in CD388’s commercial potential and plans to integrate Cidara’s team into its R&D engine. The acquisition locks in an influenza prevention asset that could complement vaccines and existing antivirals, and positions Merck to pursue seasonal and pandemic indications. Sources: company announcements and Cidara’s NAVIGATE/ANCHOR trial registrations (NCT06609460, NCT07159763).