The Berkeley, Calif., biotech said the results came in a primary endpoint analysis of a Phase 3 trial comparing Heplisav to
Engerix-B vaccine in a difficult-to-immunize population of older adults. The primary endpoint is seroprotection four weeks after the third immunization, Dynavax said.
"These results once again demonstrate Heplisav's superior effectiveness over conventional hepatitis B vaccine," said CEO Dino Dina. "The most striking outcome from the trial is the vaccine's ability to generate 98.5% protection after two doses in older difficult-to-immunize adults. This has the potential to drive an important change in the way people are immunized against hepatitis B."
Shares rose $1.71 to $9.11.