Sanofi To Acquire Dynavax For $2.2 Billion, Adding HEPLISAV-B Hepatitis B Vaccine And Z-1018 Shingles Candidate To Its Adult Immunization Portfolio

Sanofi has announced that it has reached an agreement to acquire Dynavax Technologies Corporation, a publicly listed vaccines company known for its adult hepatitis B vaccine, HEPLISAV-B, and its promising shingles vaccine candidate. This acquisition will strengthen Sanofi’s position in the adult immunization market by combining Dynavax’s products and research programs with Sanofi’s global development and commercial capabilities.

Dynavax currently markets HEPLISAV-B in the United States. The vaccine is notable for its two-dose schedule given over one month, which allows adults to achieve strong seroprotection more quickly compared with other hepatitis B vaccines that require three doses over six months. Along with the marketed hepatitis B vaccine, the acquisition also includes Dynavax’s shingles vaccine candidate Z-1018, which is currently in phase 1/2 studies, as well as several other pipeline projects focused on infectious diseases.

According to Thomas Triomphe, Executive Vice President of Vaccines at Sanofi, adding Dynavax’s portfolio will help broaden Sanofi’s adult vaccine offerings and reinforce its commitment to long-term protection across different stages of life. Dynavax’s CEO, Ryan Spencer, said that joining Sanofi will give the company the scale and resources needed to fully realize the potential of its existing products and clinical programs. He added that Sanofi’s global reach and scientific expertise will help expand the impact of HEPLISAV-B and support the advancement of its vaccine pipeline in addressing important public health challenges.

Both hepatitis B and shingles continue to be areas of significant unmet need, especially among adults. In the United States, close to 100 million adults born before 1991 remain unvaccinated for hepatitis B, leaving many at risk of infection, which can cause long-term liver damage, cirrhosis, or even liver cancer. Shingles, caused by the varicella zoster virus, affects one in three adults at some point in their lives. While many patients experience a painful rash, complications can be severe in certain cases, including chronic nerve pain, eye infections that may affect vision, and, in rare situations, inflammation of the brain.

Under the terms of the agreement, Sanofi will launch a cash tender offer to purchase all outstanding shares of Dynavax at a price of $15.50 per share, valuing the company at approximately $2.2 billion. Dynavax’s board of directors has unanimously approved the transaction. Completion of the tender offer will depend on several customary conditions, including a minimum number of shares being tendered, regulatory approvals such as clearance under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, foreign regulatory filings, and other standard closing requirements.

If the tender offer is completed, a Sanofi subsidiary will merge with Dynavax, and any remaining shares not tendered will be converted into the right to receive the same $15.50 per share in cash. Sanofi intends to finance the acquisition using its available cash. The planned acquisition is not expected to affect Sanofi’s financial guidance for 2025. If all closing conditions are met or waived as required, the deal is expected to be finalized in the first quarter of 2026.