UPDATE: Merck & Co. has just announced its agreement to acquire Cidara Therapeutics for approximately $9.2 billion, a strategic move to enhance its antiviral pipeline with a promising drug aimed at preventing influenza. This acquisition marks a significant step in Merck’s efforts to address urgent public health needs, especially for individuals at higher risk of flu complications.
Cidara’s lead candidate, CD388, is currently in the Phase III ANCHOR trial, which is designed to evaluate its effectiveness in preventing influenza among adults and adolescents deemed at risk. The trial, which began enrolling participants in September 2025, aims to include 6,000 participants across the United States and the United Kingdom.
Robert M. Davis, Chairman and CEO of Merck, stated, “We intend to build on the Cidara team’s remarkable progress and are confident that CD388 has the potential to be another important driver of growth through the next decade.” This acquisition comes on the heels of Cidara’s recent success with its Phase IIb NAVIGATE trial, which demonstrated significant prevention efficacy for CD388 against symptomatic influenza.
The NAVIGATE trial results showcased a prevention efficacy ranging from 57.7% to 76.1% among participants, establishing CD388 as a viable alternative to existing vaccines and antiviral treatments. Cidara’s President and CEO, Jeffrey Stein, emphasized the importance of this acquisition, stating, “Merck’s global development, regulatory, and commercial capabilities provide the expertise needed to bring this important innovation to those individuals who need it most.”
The deal is structured to acquire all outstanding shares of Cidara at $221.50 per share, reflecting a 109% premium over Cidara’s previous closing price of $105.99. This acquisition underscores Merck’s commitment to expanding its portfolio as it faces potential revenue losses from aging blockbuster drugs losing patent exclusivity.
Merck’s recent initiatives, including a $10 billion acquisition of Verona Pharma, demonstrate a proactive approach to maintaining its market position amid a challenging pharmaceutical landscape. Investors reacted positively, sending Cidara’s shares soaring by 105% to close at $217.71 on NASDAQ.
The acquisition is expected to close in the first quarter of 2026, pending the completion of customary conditions and the approval from Cidara’s shareholders. As Merck positions itself for future growth, the integration of Cidara’s innovative therapies could redefine influenza prevention strategies, addressing a critical gap in public health.
This pivotal transaction could enhance treatment options for millions globally, driving forward the fight against influenza and potentially saving lives in the process. As details continue to unfold, stakeholders and investors alike will be watching closely for further developments in this significant acquisition.
