Sanofi Boosts Vaccine Portfolio with $2.2B Acquisition of Dynavax
Sanofi, the French pharmaceutical titan, has finalized a definitive agreement to acquire Dynavax Technologies Corporation in an all-cash deal worth approximately $2.2 billion. Sanofi’s offer of $15.50 per share represents a 39% premium over Dynavax’s closing price as of December 23, 2025.
This strategic acquisition bolsters Sanofi’s foothold in the adult immunization sector. The deal brings with it Dynavax’s marketed hepatitis B vaccine, HEPLISAV-B. This vaccine stands out with its two-dose regimen over one month, a significant improvement over traditional three-dose schedules spanning six months. Additionally, the acquisition encompasses Dynavax’s shingles vaccine candidate Z-1018, currently in Phase 1/2 clinical development, along with other pipeline projects.
There are nearly 100 million adults in the United States, born before 1991, who remain unvaccinated against hepatitis B. This represents a significant market opportunity. The transaction, which has received unanimous approval from the boards of directors of both companies, is slated to close in the first quarter of 2026. This is, of course, subject to regulatory approvals and customary closing conditions. Sanofi plans to fund the acquisition using available cash resources.
Source: Sanofi Press Release