Sanofi has agreed to acquire U.S.-based vaccines developer Dynavax Technologies in an all-cash transaction valued at about $2.2 billion, a deal structured as a tender offer at $15.50 per share, representing a roughly 39 % premium over Dynavax’s recent closing stock price.
The agreement, approved by Dynavax’s board, is expected to close in the first quarter of 2026, subject to customary closing conditions and regulatory approvals, and will be funded using Sanofi’s available cash resources without altering its 2025 financial guidance.
Under the terms of the acquisition, Sanofi will gain control of Dynavax’s marketed adult hepatitis B vaccine, HEPLISAV-B, an approved two-dose vaccine regimen administered over one month that offers faster seroprotection compared with traditional three-dose schedules, along with a shingles vaccine candidate (Z-1018) currently in Phase 1/2 clinical development and other early-stage vaccine pipeline assets.
These assets are expected to expand and strengthen Sanofi’s adult immunization portfolio by adding differentiated products that complement its existing vaccines lineup and support broader adult vaccine coverage.
The acquisition comes at a time when adult vaccination remains a significant public health focus, with sizable populations in markets such as the United States still unvaccinated against hepatitis B, presenting commercial and health-impact opportunities for Sanofi’s expanded offerings.
