Dynavax Technologies announced positive data from the primary endpoint analysis of the company's hepatitis B virus (HBV) vaccine phase 2/3 clinical trial. The data showed statistically significant superiority in protective antibody response and robustness of protective effect after three vaccinations when compared to GlaxoSmithKline's Engerix-B vaccine in an older adult population that is difficult to immunize with conventional vaccine. The primary endpoint of the ongoing phase 2/3 trial is seroprotection four weeks after administration of the third dose.

"The clear demonstration of superiority of our HBV vaccine in a population with weakened immune responses is the cornerstone of our global regulatory and commercial strategy," said Dino Dina, MD, president and chief executive officer. "Based on the compendium of clinical data showing enhanced efficacy, faster response and shorter regimens, we believe that our vaccine could become a new standard of care, especially for populations that are at high risk, that are currently underserved and whose need for protection is urgent. These populations include dialysis patients, individuals who are infected with hepatitis C virus, people who have failed to achieve seroprotection with conventional vaccines as well as healthcare workers and international travellers. We believe we could readily compete in these high-value markets with a differentiated product that is safe and offers greater effectiveness and convenience."

Dynavax anticipates presenting the results of the primary endpoint analysis of the phase 2/3 trial at an upcoming major medical meeting. An abstract entitled, Recombinant Hepatitis B Surface Antigen (rHBsAg) Co- administered with an Immunostimulatory Phosphorothioate Oligonucleotide (1018 ISS) Provides Superior Protection in Older Subjects, has been submitted. The phase 2/3 trial is being conducted by Dr Lim Seng Gee at the National University Hospital, and Dr Chow Wan Cheng, at the Singapore General Hospital.

Dynavax's HBV vaccine combines its proprietary immunostimulatory sequence (ISS) co-administered with HBV surface antigen (HBsAg), designed to significantly enhance the level, speed and longevity of protection. Dynavax has previously reported positive interim results from the Phase 2/3 trial. Those results showed as well as positive results from a double-blind Phase 2 clinical trial conducted in young adults (18-28 years) that showed protective antibody responses were achieved faster (two vaccinations over two months compared to three over six months) and were maintained longer with Dynavax's HBV vaccine than with Engerix-B.

Dynavax intends to initiate pivotal phase 3 clinical trials of its HBV vaccine in the near-term. The first of these trials involving older adults in Asia will begin in mid-2005. A second Phase 3 trial is anticipated to begin in Canada and Europe in early 2006. The company also plans to conduct additional trials in selected high-risk populations, such as dialysis patients, in targeted markets in Europe, Canada and potentially in the United States.

Dynavax is currently evaluating global commercialization and distribution strategies for its HBV vaccine. Dynavax has a long-term supply contract with Switzerland-based Berna Biotech that includes a commercialization option. The companies are at the early stages of discussing this option.