USA News today : PARIS & EMERYVILLE, Calif. — In a move that underscores the diverging fortunes of the global pharmaceutical landscape, French healthcare giant Sanofi (SNY) has announced a definitive agreement to acquire Dynavax Technologies (DVAX) for approximately $2.2 billion in an all-cash transaction. The deal, aimed at fortifying Sanofi’s world-leading vaccine portfolio, comes at a critical juncture as the company simultaneously navigates a regulatory hurdle in its neurology pipeline, having received a Complete Response Letter (CRL) from the U.S. Food and Drug Administration (FDA) regarding its highly anticipated Multiple Sclerosis (MS) candidate.
The dual announcement highlights Sanofi CEO Paul Hudson’s “Play to Win” strategy: a ruthless prioritization of immunology and vaccines, even as the company faces the inherent volatility of drug development in high-stakes therapeutic areas.
The Dynavax Acquisition: Securing the Hepatitis B Crown
Under the terms of the agreement, Sanofi will launch a tender offer to acquire all outstanding shares of Dynavax for $18.50 per share. The price represents a significant premium over Dynavax’s recent trading average, reflecting the high value Sanofi places on Heplisav-B, the only FDA-approved two-dose hepatitis B vaccine for adults.
For Sanofi, the acquisition is a strategic masterstroke. While the company already commands a massive share of the pediatric and flu vaccine markets, the adult hepatitis B segment has long been a battlefield. Dynavax’s Heplisav-B has steadily gained market share against GlaxoSmithKline’s (GSK) three-dose incumbent, Engerix-B, thanks to its superior dosing schedule (two doses in one month versus three doses over six months) and higher seroprotection rates, particularly in “difficult-to-treat” populations such as diabetics and older adults.
“The addition of Dynavax’s proven platform and the Heplisav-B franchise aligns perfectly with our ambition to lead the vaccine market through innovation,” said Thomas Triomphe, Executive Vice President of Sanofi Vaccines. “By integrating their CpG 1018 adjuvant technology with our global manufacturing and commercial scale, we are positioned to accelerate the protection of adult populations worldwide.”
The deal also grants Sanofi access to Dynavax’s adjuvant pipeline, which is currently being explored in partnerships for shingles, Tdap, and plague vaccines. The CpG 1018 adjuvant, which played a pivotal role in several COVID-19 vaccine collaborations, is seen as a “platform-in-a-box” that could enhance the efficacy of Sanofi’s next-generation mRNA and recombinant protein vaccines.
A Stumble in Neurology: The MS CRL
The celebratory tone of the acquisition was tempered by news from the FDA. Sanofi confirmed it has received a Complete Response Letter (CRL) for its investigational Bruton’s tyrosine kinase (BTK) inhibitor, intended for the treatment of relapsing forms of Multiple Sclerosis.
The FDA’s letter reportedly requests additional data regarding long-term liver safety and the clinical meaningfulness of certain imaging endpoints. This setback is not entirely unexpected for those following the BTK inhibitor class, which has been plagued by safety concerns across the industry. Rival candidates from Merck KGaA and Roche have also faced regulatory scrutiny and clinical holds due to cases of drug-induced liver injury (DILI).
Sanofi had hoped its candidate would differentiate itself through superior brain penetration and a cleaner safety profile. While the CRL does not kill the program, it likely pushes a potential launch back by at least 18 to 24 months, allowing competitors like Novartis to further solidify their grip on the MS market with existing therapies.
“We remain confident in the potential of our BTK inhibitor to transform the lives of people living with MS,” a Sanofi spokesperson stated. “We will work closely with the FDA to address the requests in the CRL and provide the necessary data to bring this important therapy to patients.”
The Strategic Pivot: Vaccines as the Bedrock
The juxtaposition of the Dynavax deal and the MS setback illustrates Sanofi’s shifting center of gravity. Under Hudson, Sanofi has exited general medicines and consumer health to focus on “first-in-class” or “best-in-class” assets.
The $2.2 billion spent on Dynavax is seen by analysts as a “defensive-aggressive” move. As patents expire on older blockbusters, the steady, recurring revenue from a best-in-class vaccine like Heplisav-B provides the cash flow necessary to fund the riskier bets in the immunology pipeline.
Industry analyst Marc-Andre Gauthier of Biotech Insights noted, “Sanofi is making a clear statement. They are doubled down on vaccines where they have a clear competitive moat. The MS CRL is a blow to their neurology ambitions, but the Dynavax acquisition ensures that their growth engine remains fueled by reliable, high-margin products.”
Market Reaction and Future Outlook
Shares of Dynavax surged nearly 30% in pre-market trading following the announcement, while Sanofi’s stock remained relatively flat as investors weighed the vaccine acquisition against the MS delay.
The acquisition is expected to close in the first half of 2026, subject to customary closing conditions and regulatory approvals. For Dynavax, the deal represents the culmination of a decade-long journey from a struggling biotech to a commercial success story. For Sanofi, it is another piece of the puzzle in its quest to become the world’s preeminent immunology company.
As the industry looks toward 2026, all eyes will be on how Sanofi integrates the Dynavax team and whether they can successfully navigate the FDA’s stringent requirements for their MS pipeline. For now, the message is clear: Sanofi is playing to win, even if the road to victory includes a few regulatory detours.