Sanofi is boosting its vaccine portfolio and pipeline by the acquisition of Dynavax Applied sciences, a $2.2 billion deal bringing belongings that would give the corporate aggressive benefits over merchandise marketed by rival vaccines maker GSK.
The acquisition phrases introduced Wednesday name for Sanofi to pay $15.50 in money for every share of Dynavax, representing a 39% premium to the inventory’s Tuesday closing value. When Emeryville, California-based Dynavax went public in 2004, it priced its shares at $7.50 apiece.
Heplisav B, a hepatitis B vaccine accepted within the U.S. and Europe for adults, is Dynavax’s sole commercialized product. This vaccine is run as two intramuscular injections one month aside. In contrast, GSK’s Engerix-B, a hepatitis B vaccine, and Twinrix, which protects towards each hepatitis A and B, are each administered in a three-shot routine throughout six months. Dynavax contends its vaccine permits a affected person to realize excessive ranges of protecting antibodies sooner than different vaccines and with an analogous security profile.
Dynavax reported $268.4 million in Heplisav B gross sales in 2024, a 26% enhance in comparison with the prior yr. In its report of third quarter 2025 monetary outcomes, the corporate mentioned it estimates this product elevated its share of the hepatitis B vaccines market to 46%, up from 44% in 2024.
Sanofi’s presence in hepatitis B vaccines covers solely kids. Vaxelis, commercialized below a partnership with Merck, protects towards hepatitis B and 5 different pathogens. The 2023 FDA approval of Vaxelis, given in a three-shot sequence over six months, covers its use in kids from age 6 weeks by 4 years outdated.
The Dynavax pipeline consists of the shingles vaccine candidate Z-1018. In August, the corporate reported encouraging preliminary knowledge from an early-stage examine that examined this vaccine face to face towards Shingrix, the GSK product that at the moment dominates the shingles vaccine market. Dynavax mentioned its shingles vaccine was nicely tolerated, displaying decrease native and systemic post-injection reactions in comparison with Shingrix. Sturdy immune responses have been reported in any respect doses, together with the dose chosen to advance to the second a part of the Section 1/2 examine; preliminary knowledge are anticipated within the second half of 2026.
“Dynavax enhances Sanofi’s grownup immunization presence by including differentiated vaccines that complement Sanofi’s experience,” Thomas Triomphe, Sanofi’s govt vp, vaccines, mentioned in a ready assertion. “Its marketed grownup hepatitis B vaccine and shingles candidate deliver new choices to our portfolio and underscore our dedication to offering vaccine safety throughout the lifespan.”
The acquisition announcement comes as hepatitis B vaccines face larger regulatory scrutiny from the Trump administration. In early December, the Advisory Committee on Immunization Practices (ACIP), a panel that makes vaccine suggestions to the Facilities for Illness Management and Prevention, voted to advocate shared choice making for hepatitis B vaccination for kids. That’s a weaker advice than the ACIP’s decades-old advice that these vaccinations begin at delivery.
To William Blair analyst Matt Phipps, the acquisition is smart for Dynavax given rising regulatory issues round vaccines and investor questions on administration’s technique for worth creation. It additionally is smart for Sanofi.
“Sanofi is a logical acquisition companion for Dynavax given the corporate has in depth vaccine capabilities however the portfolio doesn’t have an grownup hepatitis B or shingles program,” Phipps mentioned in a analysis word.
Moreover the shingles vaccine candidate, the Dynavax pipeline features a plague vaccine in improvement below a partnership with the U.S. Division of Protection in addition to wholly owned clinical-stage applications for pandemic influenza and Lyme illness. In November, Dynavax licensed world rights to Vaxart’s oral Covid-19 vaccine candidate, at the moment in mid-stage testing. Per deal phrases, Dynavax paid $25 million up entrance and made a $5 million fairness funding in Vaxart.
Dynavax is Sanofi’s second vaccines M&A deal this yr. In July, the pharmaceutical large agreed to pay $1.15 billion to purchase Vicebio, a startup whose lead program is a bivalent vaccine in early-stage improvement for respiratory syncytial virus (RSV) and human metapneumovirus (hMPV).
Sanofi mentioned it should finance the Dynavax acquisition with obtainable money sources. The Dynavax board of administrators has accepted the deal, which nonetheless requires a majority of shareholders to tender their shares. The transaction is anticipated to shut within the first quarter of 2026.
Photograph: Francesco Carta fotografo, Getty Pictures
