Dynavax share price wilts after FDA panel snub

Dynavax Technologies ($DVAX) didn't get the safety nod it sought for its hepatitis B vaccine from FDA advisers Thursday, and its shares plummeted in extended trading. The Berkeley, CA-based biotech is seeking U.S. approval of the vaccine, Heplisav, which provides the developer its best shot at having a marketed product.

The company's visit with the FDA's Vaccines and Related Biological Products Advisory Committee was a mixed bag. The advisers voted 13-1 in favor of the vaccine's ability to block infections from the liver-attacking virus. However, the panel didn't back the safety of the vaccine candidate, voting 8-5 with one abstention that the company fell short of providing enough evidence of safety.

Dynavax's shares tumbled down as much as 60% after the panel votes in extended trading after trading was halted for the advisory committee meeting, Bloomberg reported. This morning the company's stock was trading down 49% to $2.35 per share. The setback for the stock price followed an FDA staff review that noted that the vaccine in two doses matched the efficacy of GlaxoSmithKline's ($GSK) marketed Engerix-B in three doses.

Yet physicians have and will closely scrutinize any risks associated with Heplisav, which wouldn't be the first vaccine for hep B. As Bloomberg noted, studies indicated that patients who took the vaccine candidate developed some rare side effects, including one woman who battled an inflammation of the blood vessels called Wegener's granulomatosis and another woman who developed an uncommon nerve-attacking disease called Guillain-Barre syndrome.

"Since we have vaccines that maybe aren't as optimal as we want but are effective, that is too flimsy," Edgar Marcuse, a panel member and associate medical director at Seattle Children's Hospital, said during the committee meeting, as quoted by the news service.

- here's Dynavax's release
- see Bloomberg's article
- get more from FierceVaccines

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