Listen to this articleThe basics:
- Merck to acquire Cidara for $9.2B, gaining experimental flu antiviral CD388
- CD388 is a potential single-dose, universal flu prevention now in late-stage trials
- Deal offers Merck pipeline diversification as Keytruda patent loss nears in 2028
- Acquisition follows Merck’s recent major buyouts, including Verona Pharma for $10B
Merck plans to acquire Cidara Therapeutics Inc. in a deal worth $9.2 billion.
As part of a deal announced Nov. 14, the Rahway-based drugmaker will gain access to the San Diego-headquartered biotech’s experimental flu antiviral.
Known as CD388, the therapy is under development as a non-vaccine alternative. Cidara believes the drug has the potential to be a single-dose, universal prevention against all flu strains.
CD388 has received breakthrough designation from the U.S. Food and Drug Administration. It is being studied in a late-stage trial in adults and adolescents at higher risk of developing complications from influenza.
Merck will pay $221.50 per share in cash for Cidara, a premium of 108.9% from its last closing price, the companies said. The transaction has been approved by the board of directors of both companies, they added.
The transaction is expected to close in the first quarter of 2026.
Reuters noted that the announcement comes as Merck tries to diversify ahead of patent loss for its blockbuster cancer drug Keytruda in late 2028.
Tripling the pipeline
Since 2021, Merck has nearly tripled its late-stage pipeline through in-house development and several major acquisitions.
The most recent was in October, when Merck completed a $10 billion buyout of U.K.-based Verona Pharma. Through that deal, Merck acquired Ohtuvayre, a newly approved drug for chronic obstructive pulmonary disease.
In a statement, Merck chairman and CEO Robert Davis said, “We continue to execute our science-led business development strategy, augmenting our pipeline with CD388, a potentially first-in-class, long-acting antiviral designed to prevent influenza in individuals at higher risk of complications. 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, creating real value for shareholders.”
Dr. Jeffrey Stein, president and CEO of Cidara, described the move as a “transformational moment” for his company and its mission to “redefine influenza prevention.”
“Merck’s global development, regulatory and commercial capabilities provide the expertise and resources needed to bring this important innovation to those individuals who need it most,” he said.
Vaccine scrutiny
Merck’s agreement comes amid heightened scrutiny of mRNA flu vaccines from Robert F. Kennedy Jr.’s Department of Health & Human Services.
However, Cidara has consistently emphasized throughout the year that its drug-Fc conjugates should not be confused with vaccines or monoclonal antibodies. Instead, the company describes them as low-molecular-weight biologics designed to act as “long-acting small-molecule inhibitors,” a point it reiterated in this week’s announcement.
