Dynavax Soars 39% on $2.2 Billion Acquisition by Sanofi
The French pharmaceutical giant is paying a hefty premium to acquire Dynavax's growing hepatitis B vaccine and a promising shingles candidate.
Shares of Dynavax Technologies (DVAX) surged nearly 39% in morning trading after French pharmaceutical firm Sanofi announced it would acquire the vaccine maker in an all-cash deal valued at approximately $2.2 billion.
Sanofi agreed to pay $15.50 per share, a substantial 39% premium to Dynavax's previous closing price of $11.13. The offer price pushed the stock to the top of its 52-week range, with trading volume exploding to over 75 million shares compared to a daily average of just 1.2 million, signaling strong investor approval of the buyout.
The acquisition, which was unanimously approved by the boards of both companies, brings Dynavax's flagship product, the adult hepatitis B vaccine HEPLISAV-B, into Sanofi's extensive vaccine portfolio. According to a joint press release, the deal also includes Dynavax's early-stage shingles vaccine candidate, currently in Phase 1/2 trials.
"Dynavax enhances Sanofi’s adult immunization presence by adding differentiated vaccines that complement Sanofi’s expertise," said Thomas Triomphe, Executive Vice President of Vaccines at Sanofi. He noted the deal underscores the company's "commitment to providing vaccine protection across the lifespan."
The transaction marks a strategic push by Sanofi to strengthen its position in the vaccine market. HEPLISAV-B has been a strong growth story, steadily taking market share from long-time rival Engerix-B from GSK. Recent market analysis shows HEPLISAV-B has captured approximately 44% of the U.S. adult hepatitis B vaccine market, demonstrating its competitive strength.
For Dynavax, the acquisition offers a significant acceleration in its commercial ambitions. "Joining Sanofi will provide the global scale and expertise needed to maximize the impact of our vaccine portfolio," said Ryan Spencer, CEO of Dynavax. "We are confident that this transaction – and the compelling value it provides – is in the best interests of the Company and its stockholders."
The deal also gives Sanofi a foothold in the highly lucrative shingles vaccine market, which is currently dominated by GSK's Shingrix. While Dynavax's candidate is still in early development, its inclusion provides Sanofi with a strategic option to compete in a market with high unmet needs and significant revenue potential. The shingles vaccine market has seen immense growth, making new pipeline entrants a key focus for pharmaceutical majors.
The acquisition price of $15.50 per share is notably below the average Wall Street analyst price target of $20.33 for Dynavax, which may suggest that some on the street saw higher long-term standalone value. However, the all-cash offer provides certainty and a significant immediate return for shareholders.
The transaction is expected to close in the first quarter of 2026, pending customary closing conditions, including shareholder approval and regulatory clearance. The move is the latest in a series of bolt-on acquisitions by large pharmaceutical companies seeking to replenish their pipelines with innovative assets from smaller biotech firms.