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Amended: Dynavax Plummets 57% After FDA Panel Says Hepatitis B Vaccine Data Inadequate To Establish Safety

Correcting Erroneous interpretation of FDA Panel Decision

Shares of Dynavax Technologies Corp. (DVAX) plummeted more than 57 percent in extended trading on Thursday after its Hepatitis vaccine Heplisav did not secure the backing of a U.S. Food and Drug Administration panel for its safety. However, the committee voted in favor of the drug on the efficacy aspect.

The FDA's Vaccines and Related Biological Products Advisory committee voted 13 to one, supporting the efficacy of the vaccine, terming the data as adequately demonstrating its immunogenicity.

On the other hand, the committee voted eight to five against the vaccine, with one abstention, on the grounds that data was insufficient to adequately support the safety of Heplisav.

Dynavax noted that it will continue working with the FDA to provide additional data to complete its review of the Heplisav Biologics License Application or BLA. The FDA decision date on the Heplisav BLA is set for February 24, 2013.

Dynavax has worldwide commercial rights to Heplisav, which combines hepatitis B surface antigen with a proprietary Toll-like Receptor 9 agonist to enhance the immune response. The worldwide market for adult hepatitis B vaccines is estimated to exceed $700 million annually.

Heplisav is a Phase 3 investigational adult hepatitis B prophylactic (preventive) vaccine designed to provide rapid and superior protection with fewer doses than the current commercial vaccines used to prevent hepatitis B infection like Engerix-B, produced by GlaxoSmithKline plc (GSK), and Recombivax-HB, produced by Merck $ Co. Inc. (MRK).

Dynavax submitted a Biologics License Application to the FDA for Heplisav, seeking approval for immunization against infection caused by all known subtypes of hepatitis B virus in adults 18 through 70 years of age, in April this year.

Heplisav's European licensure application has also been accepted and is under review by the European Medicines Agency or EMA.

Hepatitis B is a chronic disease which attacks the liver leading to cirrhosis of the liver or liver cancer. An estimated 2 billion people worldwide have been infected with HBV. In the U.S., 12 million people have been infected with hepatitis B while the number of chronic infections totals about 1.25 million.

Some of the FDA-approved drugs to treat hepatitis B include, Schering-Plough's Intron A, Roche's Pegasys, GlaxoSmithKline's Epivir, Gilead Sciences' Hepsera and Bristol-Myers Squibb's Baraclude, to name a few. However, there is no cure for chronic hepatitis B as yet. Therefore, prevention through effective hepatitis B vaccines is very important.

DVAX closed Thursday's regular trading session unchanged at $4.63. However, the stock plummeted $2.65 or 57.24% in the after-hours trading.

by RTTNews Staff Writer

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