Dynavax Technologies is an Emeryville, California biopharmaceutical company built around CpG 1018, a proprietary vaccine adjuvant that sharpens the immune system's response. Its flagship product, HEPLISAV-B, is the first and only two-dose adult hepatitis B vaccine approved in the U.S. and Europe, and had grown to roughly 44% U.S. market share by the end of 2024. Beyond hepatitis B, Dynavax licenses CpG 1018 to other vaccine developers - most visibly as an ingredient in several COVID-19 vaccines - and has advanced its own pipeline in shingles, plague, pandemic influenza, and Lyme disease. In December 2025 Sanofi agreed to acquire Dynavax for about $2.2 billion; the deal closed in February 2026.
Ryan Spencer is the CEO of Dynavax Technologies, the Emeryville biotech behind HEPLISAV-B and the CpG 1018 adjuvant. He joined as an interim controller in 2005, climbed for fourteen years through finance, IR, and commercial roles, and took the top job in December 2019. Under him, Dynavax supplied adjuvant for nearly a billion COVID-19 vaccine doses and, in December 2025, agreed to be acquired by Sanofi for roughly $2.2 billion.