Sanofi Strengthens Vaccine Portfolio with $2.2B Dynavax Acquisition
Sanofi has announced it has agreed to acquire Dynavax Technologies Corporation, a publicly traded vaccines company, in a move that expands Sanofi’s presence in adult immunisation and adds both a marketed hepatitis B vaccine and a shingles vaccine candidate to its pipeline.
The acquisition brings HEPLISAV-B®, Dynavax’s adult hepatitis B vaccine currently marketed in the United States, into Sanofi’s vaccines portfolio, along with Z-1018, a differentiated shingles vaccine candidate in phase 1/2 clinical development. Additional vaccine pipeline projects are also included as part of the transaction.
Strategic Acquisition Expands Sanofi’s Adult Immunisation Footprint
Sanofi stated that the acquisition is intended to strengthen its adult immunisation pipeline by combining Dynavax’s vaccine assets with Sanofi’s global scale, development expertise, and commercial reach.
Thomas Triomphe, Executive Vice President, Vaccines, Sanofi, said:
“Dynavax enhances Sanofi’s adult immunization presence by adding differentiated vaccines that complement Sanofi’s expertise. 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.”
HEPLISAV-B Differentiates in Hepatitis B Vaccination with Two-Dose Regimen
HEPLISAV-B is differentiated from other adult hepatitis B vaccines by its two-dose regimen administered over one month, enabling faster achievement of high levels of seroprotection. In comparison, other hepatitis B vaccines are typically administered in three doses over six months.
The vaccine is currently marketed in the United States and targets adult populations with unmet vaccination needs.
Early-stage Shingles Vaccine Candidate Adds Pipeline Optionality
The acquisition also includes Dynavax’s shingles vaccine candidate, Z-1018, which is currently in phase 1/2 clinical development. The addition of this program further expands Sanofi’s vaccine pipeline in adult immunisation and reflects a continued focus on infectious disease prevention across the lifespan.
Addressing Unmet Public Health Needs in Adult Vaccination
Hepatitis B and shingles continue to represent significant public health challenges. In the United States, nearly 100 million adults born before 1991 remain unvaccinated against hepatitis B, leaving many at risk of infection. Chronic hepatitis B infection can lead to liver damage, cirrhosis, and liver cancer.
Shingles, caused by the varicella zoster virus, affects one in three adults over their lifetime, according to the World Health Organisation. While often associated with a painful rash, shingles can also result in long-term nerve pain, serious eye infections with potential vision damage, and, in rare cases, inflammation of the brain.
Dynavax Highlights Scale and Global Reach under Sanofi Ownership
Dynavax emphasised that the transaction will allow its vaccine portfolio to benefit from Sanofi’s commercial reach and development capabilities.
Ryan Spencer, Chief Executive Officer, Dynavax, said:
“Joining Sanofi will provide the global scale and expertise needed to maximize the impact of our 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, further advancing our mission to help protect the world against infectious disease. We are confident that this transaction – and the compelling value it provides – is in the best interests of the Company and its stockholders.”
Transaction Valued at Approximately $2.2 Billion
Under the terms of the merger agreement, Sanofi will launch a cash tender offer to acquire all outstanding shares of Dynavax for $15.50 per share, representing a total equity value of approximately $2.2 billion.
The transaction has been unanimously approved by Dynavax’s board of directors. Completion is subject to customary closing conditions, including the tender of a majority of Dynavax’s outstanding shares, expiration or termination of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, required foreign regulatory clearances, and other standard conditions.
Following completion of the tender offer, a wholly owned subsidiary of Sanofi will merge with Dynavax, and any shares not tendered will be converted into the right to receive the same $15.50 per share in cash.
Sanofi plans to fund the acquisition using available cash resources. The company stated that the transaction is not expected to impact its financial guidance for 2025 and is expected to close in the first quarter of 2026, subject to customary closing conditions.
About HEPLISAV-B
HEPLISAV-B is an adult hepatitis B vaccine that combines hepatitis B surface antigen with Dynavax’s vaccine adjuvant, a toll-like receptor (TLR) 9 agonist, designed to enhance the immune response.
The vaccine is indicated for adults 18 years of age and older and is administered as an intramuscular injection, typically in the arm, in two doses given one month apart by a healthcare provider.
Company profiles: Sanofi and Dynavax
Sanofi is an R&D-driven, AI-powered biopharma company focused on developing medicines and vaccines to treat and protect millions of people worldwide. The company applies its understanding of the immune system across a broad pipeline and is listed on Euronext: SAN and NASDAQ: SNY.
Dynavax is a commercial-stage biopharmaceutical company developing and commercialising vaccines to protect against infectious diseases. Its products include HEPLISAV-B® [Hepatitis B Vaccine (Recombinant), Adjuvanted], which is approved in the United States, the European Union, and the United Kingdom for adults aged 18 years and older.
Original Source: Sanofi, Press Release – December 24, 2025: Sanofi to acquire Dynavax, adding a marketed adult hepatitis B vaccine and phase 1/2 shingles candidate to the pipeline
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