Dynavax Technologies Corporation, a clinical-stage biopharmaceutical company, has received a Complete Response Letter (CRL) from the US Food and Drug Administration (FDA or Agency) regarding its Biologic License Application (BLA) for Heplisav, an investigational adult hepatitis B vaccine.

In the CRL, the FDA specified that the indication in adults 18-70 years of age cannot be approved without further evaluation of safety in this broad age group. The FDA also continues to express concern that novel adjuvants may cause rare autoimmune events. However, the Agency indicated its willingness to continue discussions regarding a more restricted use of Heplisav. Dynavax plans to discuss the CRL with the FDA to identify the most expeditious path to approval for Heplisav, particularly in adults who may receive the greatest benefit from Heplisav.

Furthermore, the FDA requested additional data from Dynavax's process validation programme and clarifying information on the manufacturing controls and facilities related to the assurance of the quality of the commercial product. Dynavax believes it can provide the information but the exact timeframe for its response cannot be determined until it has met with the Agency.

Dynavax plans to meet with the FDA to discuss the steps necessary for potential approval of Heplisav and currently believes the meeting can take place within six weeks. Following its meeting with the FDA, Dynavax will provide updates as appropriate.

Dynavax's BLA was accepted for review by the FDA in June 2012. On November 15, 2012, the FDA's Vaccines and Related Biological Products Advisory Committee (Committee) voted 8 to 5 with 1 abstention that there was insufficient data to adequately support the safety of Heplisav, although the Committee voted 13 to 1 that Heplisav data adequately demonstrated immunogenicity.

Dynavax's Marketing Authorization Application continues to be under review in Europe.

Heplisav is an investigational adult hepatitis B vaccine. 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.

Dynavax, a clinical-stage biopharmaceutical company, discovers and develops novel products to prevent and treat infectious and inflammatory diseases.