Sanofi Bolsters Vaccine Portfolio with Major Dynavax Acquisition

In a strategic move to enhance its adult vaccine offerings, Sanofi has finalized a deal to acquire Dynavax Technologies Corporation for approximately $2.2 billion. The transaction, valued at $15.50 per share in cash, is set to conclude in the first quarter of 2026. This purchase price represents a significant 39% premium over Dynavax's closing share price on December 23, 2025.

The acquisition delivers two pivotal assets to Sanofi’s pipeline. The first is HEPLISAV-B®, an already commercialized hepatitis B vaccine for adults. This product stands out from competitors due to its accelerated dosing regimen. Traditional hepatitis B vaccines typically require three doses administered over six months, whereas HEPLISAV-B® achieves protection with just two doses within a single month, facilitating quicker immunization.

The second asset is Z-1018, a clinical-stage shingles vaccine candidate currently in Phase 1/2 development. Preliminary data from 2025 indicates it may elicit an immune response comparable to the market leader, Shingrix®, while demonstrating a favorable tolerability profile. An ongoing study is specifically evaluating the candidate in adults over 70 years of age.

Should investors sell immediately? Or is it worth buying Dynavax?

Sanofi’s management believes integrating these assets will accelerate progress toward its ambitious goal of generating over €10 billion in vaccine sales by 2030. The plan involves leveraging Sanofi’s extensive global commercial network to expand the reach of HEPLISAV-B® and fast-track the development of the combined research pipeline.

Dynavax's Financial Performance and Market Impact

Dynavax enters this agreement on a strong financial footing. For the third quarter of 2025, the company reported net product revenue of $90 million from its hepatitis B vaccine, marking a 13% year-over-year increase. Management has previously provided full-year 2025 revenue guidance in the range of $305 million to $325 million.

The takeover will trigger an immediate change in the equities market. Effective at the start of trading on Tuesday, February 10, 2026, Dynavax will be removed from the S&P SmallCap 600 Index. OneSpaWorld Holdings Ltd. is slated to fill the vacant position in the index.

• Acquiring Company: Sanofi
• Acquisition Target: Dynavax Technologies Corporation
• Deal Value: Approximately $2.2 billion (all-cash at $15.50 per share)
• Share Premium: 39% above the closing price on December 23, 2025
• Core Products: HEPLISAV-B® (Hepatitis B vaccine), Z-1018 (Shingles vaccine candidate)
• Index Change: Removal from S&P SmallCap 600 on February 10, 2026