Sanofi (SNY) entered a merger agreement on December 24, 2025, to acquire Dynavax Technologies Corporation (DVAX) in a deal valued at $2.2 billion.
Sanofi will commence a cash tender offer to acquire all outstanding shares of Dynavax for $15.50 per share in cash, representing a 39.26% premium from the stock’s last close.
Dynavax is a commercial-stage biopharmaceutical company that develops and markets vaccines to prevent infectious diseases, including the HEPLISAV-B hepatitis B vaccine and the CpG 1018 adjuvant, primarily in the U.S. and Europe.
Sanofi is a healthcare company that researches, develops, manufactures, and markets medicines and vaccines across pharmaceuticals, vaccines, and consumer healthcare.
Dynavax’s adult hepatitis B vaccine, HEPLISAV-B, is marketed in the United States and is differentiated by its two-dose regimen administered over one month, enabling faster achievement of high seroprotection rates compared with other hepatitis B vaccines, which require three doses over six months. Chronic hepatitis B infection can damage the liver and may lead to cirrhosis and liver cancer.
The acquisition also includes Dynavax’s shingles vaccine candidate, Z-1018, which is currently being tested in early-stage clinical trials, as well as other vaccine projects in development. Shingles is caused by the varicella zoster virus and affects about one in three adults at some point in their lives. It usually causes a painful, itchy rash, but in some people it can lead to long-lasting nerve pain, serious eye infections that affect vision, and, in rare cases, dangerous swelling of the brain.
Sanofi plans to pay for the acquisition using its existing cash and expects the deal to close in the first quarter of 2026.
Centerview Partners and Goldman Sachs advised Dynavax on the financial aspects of the deal, and Cooley acted as its legal advisor.
Sanofi’s acquisition price represents a multiple of 5.69 times the sales of Dynavax.
For a more in-depth analysis of this M&A transaction, please visit the Deal Metrics page:
Deal Metrics for the acquisition of Dynavax Technologies Corporation (DVAX) by Sanofi (SNY)
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Editor’s Note: Baranjot Kaur contributed to this article