Sanofi agreed to acquire Dynavax Technologies for $2.2 billion in cash to add Dynavax’s hepatitis B vaccine capabilities to its vaccine portfolio. The transaction expands Sanofi’s capabilities in preventive medicine and represents its largest deal in recent years to scale vaccine supply and market reach. The purchase follows regulatory headwinds for other Sanofi programs and arrives as big pharma firms aim to secure late‑stage and marketed vaccine assets. Sanofi will integrate Dynavax’s manufacturing and platform assets to support existing immunization programs and future vaccine development.