Sanofi swoops on Dynavax with $2.5bn takeover deal

 Sanofi's last job before breaking up for the Christmas holiday? Putting the finishing touches on a $2.5 billion agreement to buy vaccine developer Dynavax.

The French pharma major has started a $15.50 per share cash tender offer for Emeryville, California-based Dynavax, which already markets an adult vaccine that protects against hepatitis B virus (HBV), called Heplisav-B, sales of which came in at around $95 million in the third quarter.

First approved by the FDA in 2017, Heplisav-B has steadily gained momentum, thanks to a two-dose regimen delivered within one month, which differentiates it from rival shots like GSK's Engerix-B and MSD's Recombivax HB, which require three doses over six months.

Dynavax has said its shot is leading the market for adult HBV vaccines, and as it is not approved for use in children, it will not be affected by recent changes to paediatric immunisation recommendations in the US that could suppress use of HBV shots and – according to some experts – result in cases of hepatitis B starting to rise again after decades of declines.

Shingles shot the star?

The big attraction for Sanofi, however, is thought to be Dynavax's experimental shingles vaccine, Z-1018, which could be a rival to GSK's blockbuster Shingrix jab, which dominates the global market and made sales of $4.5 billion last year.

In a recently announced phase 1/2 trial, Z-1018 showed comparable efficacy to Shingrix but was associated with fewer local and systemic post-injection reactions, potentially giving it a tolerability edge. Dynavax is now running the second stage of the trial, looking at two doses given eight weeks apart, in people aged 70-plus who are at risk of developing shingles, and will move ahead with registration trials if those results are positive.

There are around 1 million cases of shingles annually in the US, according to the Centres for Disease Control and Prevention (CDC) data, and Shingrix is the dominant vaccine with a market share of around 95%.

Dynavax's pipeline also includes an oral COVID-19 vaccine, licensed earlier this year from Vaxart, which is in mid-stage clinical testing, as well as candidates for plague, pandemic influenza, and Lyme disease.

"Dynavax enhances Sanofi's adult immunisation presence by adding differentiated vaccines that complement Sanofi's expertise," said Thomas Triomphe, the French group's vaccines head.

"Its marketed adult hepatitis B vaccine and shingles candidate bring new options to our portfolio and underscore our commitment to providing vaccine protection across the lifespan."

It is the second acquisition for Sanofi in the vaccines space this year, coming after it bought UK developer Vicebio and its experimental respiratory syncytial virus (RSV) jab VXB-241 for $1.6 billion in July.

Sanofi said the Dynavax deal is expected to close in the first quarter of 2026. Shares in the US company were up more than 40% in pre-market trading today.

pharmaphorum spoke with Dynavax CEO Ryan Spencer at JP Morgan back in January, where he discussed both the hepatitis B and shingles vaccines.

https://pharmaphorum.com/news/sanofi-swoops-dynavax-25bn-takeover-deal