R&D driven, AI-powered biopharma company Sanofi (Euronext Paris: SAN) (Nasdaq: SNY) announced on Wednesday that it has agreed to acquire Dynavax Technologies Corporation (Nasdaq: DVAX) in an all-cash transaction valued at approximately USD2.2bn, expanding its footprint in adult immunisation with a marketed hepatitis B vaccine and a clinical-stage shingles candidate.

The transaction gives Sanofi ownership of HEPLISAV-B, an adult hepatitis B vaccine marketed in the US and differentiated by a two-dose, one-month regimen, and Z-1018, a shingles vaccine candidate currently in phase 1/2 development, alongside additional pipeline programmes.

Under terms of the agreement, Sanofi will launch a cash tender offer to acquire all outstanding Dynavax shares for USD15.50 per share, representing a premium of around 39% to Dynavax's closing price on 23 December 2025 and approximately 46% to the three-month volume-weighted average price as of the same date. Dynavax board of directors has unanimously approved the deal.

Sanofi plans to fund the acquisition using available cash resources. Completion is subject to customary closing conditions, including regulatory approvals and shareholder tender requirements, with closing expected in the first quarter of 2026.

This acquisition will support Sanofi's strategy to scale its adult vaccine portfolio by combining Dynavax's assets with Sanofi's global development and commercial capabilities, targeting significant unmet needs in hepatitis B and shingles prevention.