Sanofi Buys Dynavax for $2.2B as It Diversifies Vaccines Portfolio

SanofiDealroom has a profile for this one. Try Dealroom → has agreed to acquire US vaccine maker Dynavax Technologies in an all-cash deal valued at $2.2 billion, marking another major acquisition as the French drugmaker seeks to reduce its reliance on a small number of top-selling medicines, including Dupixent.

Sanofi will pay $15.50 per share, a 39% premium, with the transaction expected to close in the first quarter of 2026.

Dynavax, based in Emeryville, California, focuses on adult vaccines and is best known for Heplisav-B, an approved hepatitis B vaccine in the US. The company is also developing a shingles vaccine candidate, giving Sanofi both an established product and a pipeline asset as it strengthens its vaccines portfolio.

For Sanofi, the acquisition adds scale in adult immunisation and complements its existing vaccines business with differentiated technology and products. Dynavax’s assets can benefit from Sanofi’s global manufacturing, development and commercial reach, while helping address gaps in adult vaccine coverage.

The Dynavax deal is the latest in a series of sizeable transactions by Sanofi this year. In July, the company agreed to buy UK-based private biotech Vicebio for $1.5 billion, and earlier completed an up to $9.5 billion acquisition of US rare disease drugmaker BluePrint Medicines.

Together, the deals underline Sanofi’s push to diversify its growth drivers across vaccines, rare diseases and specialty medicines.

Sources:
Dynavax
Sanofi
The Wall Street Journal
CNBC
Reuters
Bloomberg

J.V.