Merck completes $9.2 billion Cidara Therapeutics acquisition for flu-prevention drug CD388

Merck completed its cash tender offer for Cidara Therapeutics at $221.50 per share after about 85.96% of Cidara's shares were tendered by the January 6 expiration, and it moved to a merger to buy the rest. The deal brings CD388, a long-acting antiviral for influenza prevention, into Merck's pipeline. Because Merck is treating it as an asset acquisition, about $9.0 billion lands in 2026 R&D expense, which is why the company's 2026 EPS outlook carries a large one-time charge.

• Price: $221.50 per share in cash
• Tender: about 27.1 million shares, or 85.96% of Cidara, by the January 6 expiration
• Accounting: about $9.0 billion of 2026 R&D expense (about $3.65 per share)
• Asset: CD388, a long-acting antiviral for flu prevention