FDA Committee Says Heplisav Hepatitis B Vaccine Is Effective, but Safety Data Inadequate

A U.S. Food and Drug Administration (FDA) committee last month concurred that Dynavax's investigational hepatitis B virus (HBV) vaccine Heplisav was effective in preventing infection, but a majority thought there was not enough data to show whether the vaccine is safe.

Widespread hepatitis B vaccination had led to a dramatic decrease in HBV incidence worldwide. GlaxoSmithKline's Engerix-B vaccine was approved more than a decade ago, and the company also makes a combination hepatitis A and B vaccine called Recombivax.

Heplisav, developed by Dynavax Technologies, includes both HBV antigens and a toll-like receptor 9 agonist that promotes immune response. A Phase 3 clinical trial of nearly 4000 healthy adults showed that 2 doses of Heplisav provided as much protection as 3 doses of Engerix-B, according to FDA briefing materials provided prior to the November 15 meeting of the Vaccines and Related Biological Products Advisory Committee. The most common adverse events for both vaccines were mild injection site reactions.

The briefing materials noted that subgroup analyses did not reveal clinically significant differences between antibody responses in younger and older study participants or between men and women. However, the committee wanted more information about how the vaccine works in different racial/ethnic groups.

Committee members also expressed concern that the vaccine might contribute to autoimmune reactions. In clinical trials, 2 people developed serious autoimmune conditions (Wegener’s granulomatosis and Guillain-Barré syndrome), but these reactions are too uncommon to determine whether they occurred by chance. The reviewers therefore recommended that post-marketing studies should be conducted if the new vaccine is approved. The full FDA is not required to follow committee recommendations, but it usually does so.

Below is an edited excerpt from a Dynavax press release describing the FDA committee decision.

Dynavax Announces FDA Advisory Committee Meeting Outcome for Heplisav

Berkeley, CA -- November 15, 2012 -- Dynavax Technologies Corporation (NASDAQ: DVAX) today announced that the U.S. Food and Drug Administration (FDA) Vaccines and Related Biological Products Advisory Committee voted 13 to one that Heplisav data adequately demonstrated immunogenicity. Additionally, the Committee voted eight to five with one abstention that there was insufficient data to adequately support the safety of Heplisav.

Now that Dynavax has received the committee's input and vote, the company will continue working with the FDA as it completes its review of the Heplisav application. The scheduled Prescription Drug User Fee Act (PDUFA) date for Heplisav is February 24, 2013.

About Heplisav

Heplisav is an investigational adult hepatitis B vaccine for which U.S. and European licensure applications have been accepted for review by the FDA and the EMA. The PDUFA date for completion of the FDA review of the Heplisav Biologic License Application is February 24, 2013. Dynavax has worldwide commercial rights to Heplisav. Heplisav combines hepatitis B surface antigen with a proprietary toll-like receptor 9 agonist to enhance the immune response.

About Dynavax

Dynavax, a clinical-stage biopharmaceutical company, discovers and develops novel products to prevent and treat infectious and inflammatory diseases. Dynavax's lead product candidate is Heplisav, a Phase 3 investigational adult hepatitis B vaccine. For more information visit www.dynavax.com.

12/21/12

Sources

Dynavax Technologies. Dynavax Announces FDA Advisory Committee Meeting Outcome for Heplisav. Press release. November 15, 2012.

Dynavax Technologies. HEPLISAV Hepatitis B Vaccine -- Vaccines and Related Biological Products Advisory Committee. Briefing Document for the 15 November 2012 Meeting.