Dynavax's Heplisav hepatitis B vaccine provides greater protection, study says

By Angela McDaniels

Seattle, Dec. 19 - Dynavax Technologies Corp. said Heplisav, its hepatitis B virus vaccine, met primary efficacy endpoints better than GlaxoSmithKline's Engerix-B vaccine during a phase 2/3 clinical trial.

Heplisav produced superior seroprotection and geometric mean concentration: 100% and 1698 mIU/mL, respectively, compared to 90.5% and 569 mIU/mL for the group treated with Engerix-B.

Results also showed that subjects treated with Heplisav experienced more durable seroprotection, the company said. At week 50, the Heplisav-treated group measured 100% seroprotection and geometric mean concentration of 499 mIU/mL, compared to 86% and 153 mIU/mL for the Engerix-B treated group.

The double-blind, controlled phase 2/3 trial was conducted in an older adult population, aged 40 to 70 years, in whom achieving seroprotection with conventional vaccine is more difficult than in younger adults, the company said.

On an intent-to-treat basis, the study involved 88 healthy, seronegative subjects aged 40 to 70 randomized into two treatment groups.

One group received three doses of Dynavax's hepatitis B vaccine, administered at a dose of 20 micrograms HBsAg plus 3 milligrams of immunostimulatory sequence, by intramuscular injection at zero, two months and six months. The other group received three doses of Engerix-B administered at a dose of 20 micrograms HBsAg by intramuscular injection at zero, one and six months.

The primary endpoint of the trial was seroprotection following three doses, and a key secondary endpoint was geometric mean concentration, a measure of the robustness of antibody response. The safety profile of the vaccine was highly favorable, the company said.

The primary endpoint analysis was based on results four weeks after administration of the third dose at week 28. Subjects were followed for an additional five months to assess duration of protective response.

The data was presented at the 45th Annual Interscience Conference on Antimicrobial Agents and Chemotherapy Washington, D.C.

"The pivotal phase 3 clinical program is well underway. Our commercial strategy is designed to target high-value, high-risk patient populations whose need for rapid and effective protection against hepatitis B is urgent and who are underserved by conventional vaccines," president and chief executive officer Dino Dina said in the release.

"We are initially focusing on patients with chronic renal failure who are either about to undergo hemodialysis or already on hemodialysis and who are at substantial risk for hepatitis B infection. We also intend to focus on people with HIV and hepatitis C infections for whom co-infection with hepatitis B is a serious concern.

"We believe that health care workers and emergency personnel, who face significant occupational risks of infection, as well as discretionary travelers, also represent important potential markets for Heplisav."

Dynavax's hepatitis B vaccine is based on its proprietary immunostimulatory sequence that specifically targets Toll-Like Receptor 9 to stimulate an innate immune response.

Dynavax is based in Berkeley, Calif., and develops products to treat and prevent allergies, infectious diseases and chronic inflammatory diseases using proprietary approaches that alter immune system responses.

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