Dynavax's hep B vaccine plans derailed by European request for extra safety data

Last week research firm GlobalData tipped the hepatitis B vaccine market to top $1 billion by 2022, with sales of Sanofi's ($SNY) Hexyon driving the sector's modest growth. Dynavax ($DVAX) hopes to claim a slice of the market too, but its hepatitis B vaccine received another blow this week.

The biotech withdrew the European market application for its vaccine, Heplisav, after the regulator said more safety data was needed. Officials at the European Medicines Agency (EMA) told Dynavax the safety database it presented to support the application was too small to rule out the risk of less common adverse events. In response, Dynavax has withdrawn the application while it works to generate the necessary clinical data.

An 8,000-subject clinical trial designed to gather additional safety data is due to start soon. Dynavax will use the results to ease the EMA's concerns, as well as to work through its issues with the FDA. Safety concerns prompted the U.S. regulator to reject Heplisav one year ago. Dynavax had hoped to quickly refile and win approval for use in a restricted population, but the FDA subsequently asked the biotech to run a new safety study.

Concerns about links between Heplisav and autoimmune disorders were raised by a FDA panel in 2012 and have dogged the vaccine ever since. The worries center on the use of a first-in-class adjuvant that activates immune responses by targeting Toll-like receptor 9. U.S. regulators have traditionally been wary of adjuvants, but Dynavax has seemingly found the EMA no more receptive to its product. GlobalData predicts Heplisav will generate peak sales of $85 million, leaving Sanofi, GlaxoSmithKline ($GSK) and Merck ($MRK) as the dominant players.

- here's the Reuters article
- read the press release
- check out GlobalData's analysis