MSD takes over Cidara. The laboratory has made an offer of $9.2 billion (€8 billion) to acquire the biotech, based in San Diego. A colossal amount worthy of the challenge: recovering the rights to CD388, an antiviral positioned as an alternative to preventive vaccines against seasonal flu.
Generally associated with fever and intense cough, the flu is one of the most common respiratory infections. Although it can be cured within a few weeks in healthy people, it can prove fatal in certain populations at risk, including seniors, newborns and immunocompromised people. In 2024, it is thus responsible for 1.3 million hospitalizations and 130,000 deaths worldwide.
Faced with this seasonal epidemic, the vaccine, of which Sanofi is one of the specialists, remains the most effective means of prevention. However, in certain people, particularly those with cancer, it can cause serious complications. To address this public health problem, which would impact 110 million people in the United States alone according to MSD, Cidara has developed CD388, a new generation drug with an innovative mechanism.
Unlike traditional vaccines, which work by stimulating the immune system to produce antibodies, the drug candidate works by combining an antiviral with a human antibody fragment, to give it prolonged action in the body. A technology called Drug-FC Conjugatewhich has already demonstrated its effectiveness.
During phase II clinical trials, CD388 prevented flu symptoms for 76.1% of participants over a period of six months, thus providing complete seasonal protection.
A strategic transaction for MSD
By paying $9.2 billion to buy Cidara, MSD was generous. The laboratory thus formulated an offer twice the value of Cidara’s shares at the time of the announcement. It must be said that the laboratory wants to believe in the potential of CD388, which would be the first treatment on the market for preventing influenza without a vaccine.
« We are confident that CD388 has the potential to become another significant growth engine over the next decade », justified Robert M. Davis, CEO of MSD. The laboratory therefore expects the drug to bring in more than $5 billion over the next few years.
Currently evaluated in phase III, the drug is on track to obtain authorization quickly. Especially since it benefits from the status “ Fast Track » and the designation “ Breakthough Therapy » in the United States, systems aimed at facilitating the approval of innovative drugs or those meeting unmet needs.
An operation in line with the diversification strategy undertaken by MSD, which seeks to compensate for the loss of income linked to the expiration of the patent for its Keytruda (pembrolizumab) by the end of the decade. For several consecutive years, the drug has been the best-selling drug in the world, with $28.5 billion in sales in 2024.
With this new acquisition, which must be finalized in the first quarter of 2026, MSD completes an infectious pipeline already composed of several antivirals, including one against Covid-19, and drugs intended for patients at high risk of influenza complications.
This is the second major acquisition for MSD in 2025. In July, the laboratory had already spent $10 billion to acquire the British biotech Verona Pharma and recover from a “ future blockbuster », approved against COPD.