Dynavax’s Heplisav Vaccine Works on Hepatitis B, FDA Says

Dynavax Technologies Corp.’s Heplisav vaccine works against the contagious liver disease hepatitis B, Food and Drug Administration staff said. The company’s shares jumped the most in about 14 months on the report.

Heplisav worked as well after two doses as three doses of GlaxoSmithKline Plc’s Engerix-B vaccine to protect patients against the virus, FDA staff said today in a report released ahead of an advisory panel meeting scheduled Nov. 15 on Dynavax’s vaccine. Heplisav also had a similar safety profile to Engerix-B, agency staff said.

Heplisav would be Berkeley, California-based Dynavax’s first product if the vaccine is cleared by Feb. 24 when the FDA is scheduled to decide on approval. The vaccine may generate an estimated $775 million in peak worldwide sales in 2020, Katherine Xu, an analyst with William Blair & Co. in New York, said in an e-mail.

Dynavax rose 13 percent to $4.74 at the close in New York, the largest single-day increase since Sept. 16, 2011. The company has gained 43 percent this year.

Dynavax originally sought to market the drug to healthy adults ages 40 and older. When the company met with the FDA in February, the agency determined the vaccine should be for healthy adults 18 to 70 years old.

Attacks Liver

Hepatitis B, like HIV, is transmitted through the exchange of body fluids such as blood, saliva or semen, according to the Centers for Disease Control and Prevention. It attacks the liver, which removes toxins from the body, and can lead to scarring, cancer or organ failure.

In a final-phase study of about 2,400 patients ages 18 to 55, 95 percent of those who took two doses of Heplisav were protected from hepatitis B compared with 81 percent of those who took three doses of Glaxo’s Engerix-B, FDA staff said in a report.

FDA staff recommended evaluation of Heplisav after the drug is on the market because some patients experienced autoimmune diseases. Two main trials on the vaccine weren’t set up to detect such rare adverse events, according to the report.

One woman experienced Wegener’s granulomatosis, a rare disease in which blood vessels are inflamed and another woman developed Guillain-Barré syndrome, a disorder in which the body’s immune system attacks the nerves. The woman with Guillain-Barré syndrome also received an influenza vaccine that was thought to have caused the disorder rather than Heplisav.

The FDA put a hold on two clinical trials in March 2008 after a patient given the vaccine was diagnosed with Wegener’s granulomatosis. U.S. regulators allowed testing to resume in September 2009.

Dynavax plans to submit an application to expand Heplisav’s use to patients with chronic kidney disease if the drug is approved in healthy adults, the company has said.

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