Merck Completes Strategic Acquisition of Cidara Therapeutics in $9.2 Billion Deal

CIDARA THERAPEUTICS US1717572069

Pharmaceutical giant Merck & Co. has finalized its acquisition of Cidara Therapeutics, bringing the clinical-stage biotech firm fully under its corporate umbrella in a transaction valued at approximately $9.2 billion. The move is widely seen as a strategic play to bolster Merck's pipeline, with a particular focus on the promising antiviral candidate CD388.

Shareholders of Cidara are receiving $221.50 in cash for each share they hold. The deal, which was confirmed on January 7 following a successful tender offer, saw Cidara's stock trading near the offer price at the market open. Merck secured financial advisory services from BofA Securities, while Cidara was counseled by Evercore and Goldman Sachs.

To fund the acquisition, Merck utilized a combination of newly issued debt and commercial paper. This financing structure included a substantial $8 billion bond issuance that was completed in December.

The Strategic Driver: Antiviral Candidate CD388

At the heart of this acquisition is CD388, an investigational long-acting antiviral designed for the universal prevention of both Influenza A and B. The candidate is a Drug-Fc Conjugate, a mechanism intended to provide protection without directly activating the patient's immune system. This profile makes it potentially valuable for high-risk populations, including the elderly and immunocompromised individuals.

CD388 is currently being evaluated in the Phase 3 ANCHOR trial, which has successfully met its enrollment target of 6,000 patients. The study is scheduled to run through late 2025. Merck has outlined that an interim analysis is planned for the first quarter of 2026. The outcome of this review could support an early regulatory submission or may necessitate expanded patient recruitment in the Southern Hemisphere.

For Merck, the purchase aligns with a broader strategy to diversify its respiratory portfolio and mitigate future financial risk, especially as it faces the impending patent expiration for its flagship oncology drug, Keytruda.

Integration Plans and Forward-Looking Catalysts

With the transaction closed, Cidara shares will be delisted from the Nasdaq exchange. Future developments concerning CD388 and Cidara's Cloudbreak® platform will be reported within Merck's consolidated corporate updates.

The company has announced it will provide further details regarding integration costs and updated revenue projections during its fourth-quarter and full-year 2025 earnings presentation on February 3, 2026.

Market analysts from firms including Guggenheim and BofA have identified the success of CD388 as a pivotal component in Merck's ambition to generate an additional $70 billion in revenue by the mid-2030s. Consequently, the interim analysis in early 2026 stands as the most significant near-term catalyst for the newly acquired business unit.