Merck Acquires Cidara Therapeutics, Expands Portfolio with Antiviral Innovations

Merck has entered into a definitive agreement to acquire Cidara Therapeutics for approximately $9.2 billion. The deal values Cidara’s shares at $221.50 each.

Strategic Acquisition Expands Merck’s Portfolio

This acquisition aligns with Merck’s strategy to enhance its pipeline through innovative science-led business development. CD388, Cidara’s long-acting antiviral agent, is a key part of this strategy. The drug is currently in Phase 3 trials aimed at preventing influenza in high-risk populations.

Details on CD388

CD388 is a drug-Fc conjugate that serves as a neuraminidase inhibitor designed for broader flu prevention. It is being tested in the Phase 3 ANCHOR study, which engages adult and adolescent participants susceptible to influenza complications.

• Clinical Studies:
  • ANCHOR Study (NCT07159763): Ongoing with a target enrollment of 6,000 participants.
  • NAVIGATE Study: Demonstrated strong efficacy in preventing influenza and achieved all primary and secondary endpoints.
• FDA Designations:
  • Breakthrough Therapy Designation granted in October 2025.
  • Fast Track Designation previously given by the FDA.

Significance of the Acquisition

Merck’s acquisition is expected to complement its respiratory drug portfolio. Influenza remains a critical global health issue, affecting millions annually. In the U.S. alone, the flu causes substantial health complications and tens of thousands of deaths each year.

Merck’s CEO, Robert M. Davis, emphasized that the acquisition of Cidara aims to enhance shareholder value and promote development in antiviral innovations. The merger is subject to approval from Cidara’s stockholders and other regulatory conditions, with closure anticipated in the first quarter of 2026.

About the Companies

Founded as a premier biopharmaceutical company, Merck, known as MSD outside North America, has a long history of creating impactful medicines. Cidara Therapeutics focuses on the development of drug-Fc conjugates using its proprietary Cloudbreak platform to tackle infectious diseases effectively.

This merger signifies a significant step towards enhancing antiviral treatments and addressing unmet public health needs related to influenza.