Dynavax Technologies Corp. /zigman2/quotes/203017054/composite DVAX +6.42% said late Thursday it will focus on its vaccine business and on its first commercial product, a hepatitis B vaccine, looking to unwind its immuno-oncology business. The company will also lay off workers and trim operations to focus on the vaccine's commercialization. "Following a comprehensive analysis of our assets, strengths and opportunities, we have determined we should focus our resources on our approved vaccine, HEPLISAV-B, which, as the only two-dose hepatitis B vaccine, is gaining market share and is well positioned to become the new standard of care in the U.S," Chief Executive Eddie Gray said. In the same press release, Gray said that the restructuring was "the optimal time" for his retirement, effective Aug. 1. The company's board of directors has created an interim office of the president and has appointed David Novack and Ryan Spencer, two senior vice presidents, as co-presidents effective immediately. Shares of Dynavax, halted earlier in the extended session, fell more than 5% when they resumed trading. The shares ended the regular session 0.2% lower.