A healthcare titan wants to buy the biotech's vaccines.Shares of Dynavax Technologies (DVAX +38.19%) popped on Wednesday after the vaccine maker struck a deal to be acquired by Sanofi (SNY +0.08%). As of 3:00 p.m. EST, Dynavax's stock price was up more than 38%. An appealing offer for Dynavax's investorsUnder the terms of the deal, Sanofi will begin a tender offer to purchase Dynavax's stock for $15.50 per share in cash. That values the biotech at roughly$2.2 billion, a premium of 39% compared to its closi ...