US pharmaceutical company Merck & Co Inc (NYSE:MRK), known as MSD outside the US and Canada, confirmed on Wednesday that it has completed its cash tender offer for all outstanding shares of Cidara Therapeutics Inc (Nasdaq:CDTX), a biotechnology company developing drug-Fc conjugate (DFC) therapeutics.

Merck paid USD221.50 per share, acquiring approximately 85.96% of Cidara's shares.

Subsequently, Merck intends to merge its subsidiary into Cidara, making Cidara a wholly owned subsidiary, and Cidara's Nasdaq-listed shares will be cancelled. All shares of common stock not tendered into the offer will be cancelled and converted into the right to receive cash equal to the USD221.50 offer price per share.

The acquisition is expected to be treated as an asset acquisition, increasing Merck's 2026 R&D expenses by approximately USD9.0bn and reducing GAAP and non-GAAP EPS by approximately USD0.30 per share in the first year.

Cidara's lead asset, CD388, is a long-acting, strain-agnostic antiviral currently in Phase 3 development to prevent influenza in high-risk individuals. The drug has received Breakthrough Therapy and Fast Track designations from the US Food and Drug Administration (FDA), based on positive Phase 2b study results.

Merck views this acquisition as a strategic expansion of its respiratory portfolio and pipeline, aligned with its science-led business development approach. The company plans to advance CD388 toward potential market approval while leveraging Cidara's existing expertise.