Let’s make a deal, Merck (NYSE: MRK) to acquire Cidara for $9.2 billion

Merck (NYSE: MRK) announced it will acquire Cidara Therapeutics (CDTX) for $221.50 per share in cash, valuing the transaction at approximately $9.2 billion. The acquisition centers on Cidara’s lead candidate CD388, an investigational antiviral agent currently in Phase 3 trials for influenza prevention.

CD388 is designed to prevent influenza A and B infections in individuals at higher risk of complications. The drug consists of a small molecule neuraminidase inhibitor conjugated to a proprietary fragment of a human antibody. The U.S. Food and Drug Administration granted CD388 Breakthrough Therapy Designation based on results from the Phase 2b NAVIGATE study, which met its primary and secondary endpoints for preventing symptomatic laboratory-confirmed influenza in healthy unvaccinated adults ages 18 to 64.

The drug is currently being evaluated in the Phase 3 ANCHOR study among adult and adolescent participants at higher risk of developing influenza complications. The study began dosing participants in September and has a target enrollment of 6,000 participants across 150 sites in the United States and United Kingdom. An interim analysis is planned for the first quarter of 2026.

Both companies’ boards of directors have approved the transaction. The acquisition is structured as a tender offer and is subject to a majority of Cidara stockholders tendering their shares, expiration of the Hart-Scott-Rodino antitrust waiting period, and other customary conditions. The transaction is expected to close in the first quarter of 2026.