French pharmaceutical giant Sanofi SA said on Wednesday it has agreed to acquire US-based vaccines company Dynavax Technologies Corp in a $2.2 billion deal, strengthening its presence in the adult immunization market.
Under the agreement, Sanofi will launch a cash tender offer of $15.50 per Dynavax share, representing a 39% premium to the company’s pre-deal stock price.
Dynavax’s portfolio includes the US-marketed adult hepatitis B vaccine HEPLISAV-B, which features a two-dose regimen over one month, offering faster protection than traditional three-dose vaccines. The acquisition also brings Dynavax’s shingles vaccine candidate, Z-1018, currently in early-stage clinical trials, along with other pipeline projects.
“Dynavax enhances Sanofi’s adult immunization presence by adding differentiated vaccines that complement Sanofi’s expertise,” said Thomas Triomphe, executive vice president, vaccines, Sanofi. “Its marketed adult hepatitis B vaccine and shingles candidate bring new options to our portfolio and underscore our commitment to providing vaccine protection across the lifespan.”
Dynavax CEO Ryan Spencer told investors that joining Sanofi will give Dynavax the global scale and expertise needed to maximize the impact of its vaccine portfolio. “We believe Sanofi’s commercial reach, development capabilities, and commitment to evidence-based immunization will amplify the opportunity for HEPLISAV-B and our innovative pipeline to address important public health needs.”
Adult vaccination remains a major public health challenge in the US, with nearly 100 million adults born before 1991 unvaccinated against hepatitis B. Shingles affects roughly one in three adults during their lifetime, often causing severe nerve pain and, in rare cases, serious complications.
Sanofi said the acquisition will be funded with cash reserves and is not expected to impact its 2025 financial guidance.
Dynavax shares surged 39% in early US trading following the announcement.