Dynavax Technologies saw its shares surge 39.26% in pre-market trading after Sanofi announced a $2.2 billion cash offer to acquire the vaccine manufacturer. The proposed deal values Dynavax at $15.50 per share, representing a 39% premium over its last closing price. This acquisition aims to bolster Sanofi's adult immunization portfolio, leveraging Dynavax's hepatitis B vaccine and a promising shingles vaccine candidate currently in early trials. The transaction is expected to be finalized in the first quarter of 2026.