Efforts to innovate within the combat in opposition to influenza embody common influenza vaccines — none profitable to date. Merck is aiming for universality with a drug, not a vaccine, by way of the $9.2 billion acquisition of Cidara Therapeutics, a biotechnology firm whose lead program brings properties of each small molecule and biologic therapies to supply long-acting safety in opposition to viral pathogens.
The deal introduced Friday comes as San Diego-based Cidara continues Part 3 testing of its influenza drug candidate, CD388. For Merck, the deal diversifies its pipeline by including a late-stage asset with blockbuster potential together with a platform expertise that might assist the pharmaceutical large’s drug R&D work in infectious illness and past.
As a common influenza drug, CD388 is meant to guard in opposition to each influenza A and B viruses in addition to strains that might trigger a pandemic, similar to H5N1, Cidara mentioned in its annual report. Cidara’s medicine have two primary elements, every with a distinct mechanism of motion. The primary half is a small molecule designed to bind to a goal on the floor of the pathogen to inhibit viral proliferation. The small molecule is conjugated to the second element, the Fc area of the human antibody IgG1. This protein fragment extends a Cidara drug’s half-life and engages the immune system to supply a further response. Cidara calls this new sort of remedy a drug-Fc conjugate, or DFC.
CD388 incorporates a number of copies of small molecule inhibitors of neuraminidase, an enzyme discovered on the floor of flu viruses. Neuraminidase inhibitors are already broadly accessible in influenza antiviral merchandise similar to Tamiflu from Roche and Relenza from GSK. In Cidara’s drug, the neuraminidase inhibitors are conjugated to an Fc fragment. Cidara is growing this DFC for the prevention of influenza an infection in these at larger danger of flu problems. The corporate has mentioned that as a result of CD388 isn’t a vaccine, it doesn’t depend on an immune response and is anticipated to work in these with weaker immune methods. Additionally, its long-acting impact affords the potential for cover throughout your complete flu season.
This previous June, Cidara reported preliminary information from a placebo-controlled Part 2b examine that enrolled about 5,000 unvaccinated adults. Outcomes confirmed the subcutaneously injected drug met the examine’s primary objective, demonstrating statistically vital prevention efficacy for every of the three doses examined. The examine drug was protected and effectively tolerated.
In September, Cidara started a Part 3 examine whose begin was accelerated by six months to be able to overlap with the 2025 flu season within the Northern Hemisphere. This system will proceed into the spring of subsequent yr to enroll members within the Southern Hemisphere. Merck mentioned an interim evaluation is deliberate for the primary quarter of 2026 to evaluate trial dimension and powering assumptions, and in addition to find out whether or not to extend enrollment past the 6,000 members deliberate for the examine.
With the Cidara acquisition, Merck is getting an asset that Johnson & Johnson deserted. In 2021, Cidara entered a partnership with J&J subsidiary Janssen Prescribed drugs, which secured international rights to CD388 and took over Part 2 growth. However in 2023, Janssen stopped work on a lot of its infectious illness pipeline, together with the Cidara antiviral. Final yr, Cidara reacquired rights to CD388 and raised funding to proceed mid-stage medical growth of this system.
Merck may even get Cloudbreak, the proprietary Cidara platform expertise that yielded CD388. Cloudbreak has extra purposes in oncology and it has produced DFCs for targets in strong tumors, the place the biotech mentioned one of these remedy might have benefits over antibody drug conjugates. Cidara has been exploring enterprise alternatives for these preclinical packages, however Merck may select to maintain them for its personal most cancers pipeline.
Merck’s portfolio is headlined by the most cancers immunotherapy Keytruda, which accounted for $29.4 billion in income in 2024 and is presently the corporate’s top-selling product. However Keytruda faces patent expiration in 2028, so Merck has been placing enterprise offers for late-stage medicine with the potential to interchange Keytruda’s income. Earlier this yr, Merck paid $10 billion to purchase Verona Pharma, whose blockbuster prospect Ohtuvayre is accepted for treating power obstructive pulmonary illness and has potential purposes in different respiratory problems. Merck’s enterprise growth efforts in 2024 included offers that introduced blockbuster prospects for most cancers and eye illnesses.
The $9.2 billion acquisition worth for Cidara breaks right down to $221.50 in money per share. That’s greater than double the inventory’s Thursday closing worth. When Cidara went public in 2015, the then preclinical biotech priced its shares at $16 apiece. Cidara’s inventory worth has been climbing steadily for the reason that June report of Part 2 information for CD388.
“This acquisition expands and enhances our respiratory portfolio and pipeline,” Dean Li, president of Merck Analysis Laboratories, mentioned in a ready assertion. “Influenza continues to pose a big international well being risk, inflicting widespread sickness, morbidity and loss of life annually particularly in older adults and immunocompromised people, similar to these with most cancers and power illnesses.”
The Merck and Cidara boards of administrators have accepted the transaction, which is anticipated to shut within the first quarter of 2026. Merck has scheduled a Monday 8 a.m. investor name to debate the deal.
Picture by Flickr person quapan by way of a Artistic Commons license
