Merck (NYSE: MRK), known as MSD outside of the United States and Canada, announced the successful completion of the cash tender offer, through a subsidiary, for all the outstanding shares of common stock of Cidara Therapeutics, Inc. (Nasdaq: CDTX) (“Cidara”).
“The acquisition of Cidara strengthens and complements our expanding respiratory portfolio and exemplifies our business development strategy of investing where compelling science and value meet,” said Robert M. Davis, chairman and chief executive officer, Merck. “CD388, a potentially first-in-class, long-acting antiviral with strain-agnostic properties, underscores that approach. We look forward to building on Cidara’s progress and further evaluating the potential of this candidate for the prevention of symptomatic influenza in certain individuals at high risk of complications.”
Merck completed the cash offer at a purchase price of $221.50 per share of common stock of Cidara, without interest and subject to deduction for any required tax withholding. As of the tender offer expiration at one minute after 11:59 p.m., Eastern Time, on January 6, 2026, 27,149,333 shares of common stock were validly tendered and not withdrawn, representing approximately 85.96% of the total number of Cidara’s issued and outstanding shares of common stock. All such shares have been accepted for payment in accordance with the terms of the tender offer, and Merck expects to promptly pay for such shares.
Merck intends to complete the acquisition through a merger of Merck’s wholly owned subsidiary with and into Cidara, with Cidara being the surviving corporation, in which all shares of common stock not tendered into the offer will be cancelled and converted into the right to receive cash equal to the $221.50 offer price per common share, without interest and subject to deduction for any required tax withholding. After the completion of the merger, Cidara will become a wholly owned subsidiary of Merck and the common stock of Cidara will no longer be listed or traded on the Nasdaq Global Market. The acquisition is expected to be accounted for as an asset acquisition, resulting in a charge that will increase 2026 research and development expenses by approximately $9.0 billion or approximately $3.65 per share, included in GAAP and non-GAAP results. Additionally, GAAP and non-GAAP EPS are expected to be negatively impacted by approximately $0.30 per share in the first 12 months, representing costs associated with advancing CD388 and costs of financing.
About Influenza
Influenza is an acute respiratory infection caused predominantly by influenza viruses A and B. An estimated one billion people worldwide are infected by seasonal influenza each year. Of the one billion, three to five million have severe cases of flu. Complications include pneumonia, exacerbation of chronic conditions, sepsis, myocarditis, encephalitis and death in the most severe cases. Globally, an estimated 290,000-650,000 deaths occur due to flu each year with 6,300-52,000 deaths in the U.S.
About CD388
CD388 is an investigational drug-Fc conjugate (DFC) comprised of multiple copies of a potent small molecule neuraminidase inhibitor stably conjugated to a proprietary Fc fragment of a human antibody. DFCs are not vaccines or monoclonal antibodies but are low molecular weight biologics which are designed to function as long-acting small molecule inhibitors. CD388 was designed to prevent influenza infection in individuals at higher risk of influenza complications with the potential to provide season-long protection. In preclinical studies, broad antiviral activity has been observed against influenza A and B viruses, including certain strains of pandemic concern. CD388 is not a vaccine, therefore its activity is not dependent on an immune response and is expected to be efficacious in individuals regardless of immune status. CD388 is currently being evaluated in the Phase 3 ANCHOR study (NCT07159763) among adult and adolescent participants who are at higher risk of developing complications from influenza.
About Merck
At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than 130 years, we have brought hope to humanity through the development of important medicines and vaccines. We aspire to be the premier research-intensive biopharmaceutical company in the world - and today, we are at the forefront of research to deliver innovative health solutions that advance the prevention and treatment of diseases in people and animals. We foster a diverse and inclusive global workforce and operate responsibly every day to enable a safe, sustainable and healthy future for all people and communities.