BREAKING NEWS: Merck & Co. has officially announced its acquisition of Cidara Therapeutics for approximately $9.2 billion, a move that significantly enhances Merck’s antiviral pipeline. This acquisition comes as Cidara’s promising drug, CD388, is currently in Phase III trials aimed at preventing influenza in high-risk individuals.
This transformative deal was confirmed just moments ago and is set to bolster Merck’s efforts to address urgent public health needs. The acquisition, which values Cidara at $221.50 per share, represents a 109% premium over the company’s closing price prior to the announcement.
The lead candidate, CD388, is a long-acting antiviral designed to offer universal prevention against both seasonal and pandemic influenza. Currently, it is undergoing testing in the Phase III ANCHOR trial (NCT07159763), which aims to evaluate its efficacy among adults and adolescents at heightened risk for influenza complications. This trial commenced in September 2025 and is expected to enroll up to 6,000 participants across 150 sites in the U.S. and the UK.
Robert M. Davis, Merck’s Chairman and CEO, stated, “We intend to build on the Cidara team’s remarkable progress… creating real value for shareholders.” This acquisition follows Cidara’s recent success in the Phase IIb NAVIGATE trial, where CD388 demonstrated a statistically significant prevention efficacy of up to 76.1% in preventing symptomatic influenza among participants.
The urgency of this acquisition is underscored by ongoing concerns surrounding influenza outbreaks, particularly in vulnerable populations. As the flu season approaches, the need for effective preventative measures is more critical than ever.
Cidara’s president and CEO, Jeffrey Stein, PhD, highlighted the importance of this partnership, stating, “Merck’s global development… capabilities provide the expertise needed to bring this important innovation to those individuals who need it most.”
Merck is strategically positioning itself to replace revenue from aging blockbuster drugs, including Keytruda and Gardasil, which are set to lose patent protection soon. The acquisition of Cidara is part of a broader strategy to enhance Merck’s portfolio in response to the so-called “patent cliff” that many pharmaceutical companies face.
Investors reacted positively to the news, sending Cidara’s shares soaring by over 105%, closing at $217.71 on NASDAQ. Meanwhile, Merck’s shares remained stable at $92.93 on the New York Stock Exchange.
The deal has been approved by both Merck and Cidara’s boards and is expected to finalize in the first quarter of 2026, pending regulatory approvals. This acquisition marks a significant milestone in the fight against influenza, with potential implications for public health on a global scale.
As Merck moves forward with this acquisition, all eyes will be on the outcomes of the ANCHOR trial and how CD388 could transform influenza prevention strategies in the near future. Stay tuned for more updates as this developing story unfolds.
