Dynavax Presents Pivotal Phase 3 Data Showing HEPLISAV-B(TM) Provides Significantly Higher Protection Against Hepatitis B Than Engerix-B(R)

BERKELEY, CA--(Marketwired - April 18, 2016) - Dynavax Technologies Corporation (NASDAQ: DVAX) today announced results from HBV-23, a pivotal Phase 3 trial that provides head-to-head safety and immunogenicity data comparing its investigational adult hepatitis B vaccine, HEPLISAV-B, with the leading vaccine, Engerix-B, in adults 18 to 70 years of age. These data were presented at the National Foundation for Infectious Diseases' (NFID) 19th Annual Conference on Vaccine Research (ACVR) in Baltimore, MD.

Results of the trial demonstrated that both co-primary endpoints were met. HEPLISAV-B provided a statistically significant higher rate of protection with fewer doses than Engerix-B with a similar safety profile.

HBV-23 was a randomized, observer-blinded, active-controlled, multi-center study. Participants were randomized to HEPLISAV-B or Engerix-B in a two to one ratio. They were stratified into two age groups, 18 to 39 years and 40 to 70 years. Two doses of HEPLISAV-B were given one month apart compared to the conventional Engerix-B regimen of three doses given over six months. HEPLISAV-B participants were followed for 52 weeks after the last dose, and Engerix-B participants were followed for 28 weeks after the last dose. 

HEPLISAV-B demonstrated statistically significant higher protection rates than Engerix-B in both age groups. The seroprotection rate in all participants who received HEPLISAV-B was 95 percent compared to 81 percent for Engerix-B. Of participants 18 to 39 years of age, 99 percent who received HEPLISAV-B and 93 percent who received Engerix-B were seroprotected. In participants 40 to 70 years of age, a larger difference in seroprotection rates was seen with the HEPLISAV-B rate of 95 percent compared to 79 percent for Engerix-B.

The rates of local and systemic reactions, adverse events, serious adverse events, and deaths were similar between the HEPLISAV-B and Engerix-B groups. All adverse events considered to represent potential immune-mediated disorders were reviewed by an independent, blinded Safety Evaluation and Adjudication Committee and classified as not related to vaccination. Of the new onset immune-mediated adverse events, Bell's palsy occurred in 0.09% of HEPLISAV-B and 0.04% of Engerix-B participants. Additionally, in the HEPLISAV-B group, there was a single case each of alopecia areata, polymyalgia rheumatica, and ulcerative colitis. With the HBV-23 trial, the total safety database now comprises 14,238 participants: 10,038 of whom received HEPLISAV-B and 4200 of whom received Engerix-B.