Dynavax Presents Data Showing That HEPLISAV-B Provides Significantly Higher Seroprotection Rates Against Hepatitis B Infection in Populations Known to Have a Reduced Immune Response to Currently Licensed Vaccines

BERKELEY, CA--(Marketwired - October 26, 2016) - Dynavax Technologies Corporation (NASDAQ: DVAX) today announced sub-group results from HBV-23, the pivotal Phase 3 trial of its investigational hepatitis B vaccine HEPLISAV-B™ [Hepatitis B Vaccine, Recombinant (Adjuvanted)]. The new subgroup analysis demonstrated that HEPLISAV-B, when administered as two doses over one month, induced significantly higher seroprotection rates than the approved hepatitis B vaccine Engerix-B^®, when administered as three doses over six months. This result was observed in all prespecified groups of study participants, including those with characteristics that are known to have a reduced immune response to currently licensed hepatitis B vaccines. These characteristics include older age, high body mass index (BMI), diabetes mellitus, male gender and persons who smoke. The data were presented today in the "Vaccines: New and Novel" Poster Abstract Session at the Infectious Diseases Society of America's (IDSA) annual IDWeek 2016 meeting in New Orleans.

"Hepatitis B remains an important health problem in the United States with approximately 20,000 new infections in adults every year. Although hepatitis B vaccines have been available for 25 years and served an important role in preventing the disease, approved hepatitis B vaccines have several limitations, including lower protection rates in some populations," said Rob Janssen, M.D., chief medical officer for Dynavax. "We were encouraged to see that HEPLISAV-B administered as two doses over one month provided a significantly higher rate of seroprotection in these individuals than the existing hepatitis B vaccine. The lower immunogenicity observed in sub-groups in the Engerix-B arm of this Phase 3 study demonstrates the critical need for a hepatitis B vaccine that can provide higher rates of seroprotection with fewer doses to adequately protect adults against the consequences of this chronic viral infection."

Results of New Analysis of Phase 3 Study (Poster #754)
The pivotal Phase 3 trial, HBV-23, was a randomized, observer-blinded, active-controlled, multi-center study that compared two doses of HEPLISAV-B over four weeks with three doses of Engerix-B over 24 weeks in 8,374 adults age 18 to 70. Demographics consisting of age, sex and race were generally similar between the two treatment arms. Overall study results showing a significantly higher seroprotection rate with HEPLISAV-B versus Engerix-B (95.4 percent at week 24 vs. 81.3 percent at week 28, respectively) and comparable safety were previously reported.