Dynavax Updates sBLA for Four-Dose HEPLISAV-B® for Hemodialysis Adults in the U.S.

EMERYVILLE, Calif., May 14, 2024 -- Dynavax Technologies Corporation (Nasdaq: DVAX) has announced a regulatory update regarding their supplemental Biologics License Application (sBLA) for a four-dose regimen of the HEPLISAV-B® vaccine, specifically aimed at adults undergoing hemodialysis. The U.S. Food and Drug Administration (FDA) has issued a Complete Response Letter (CRL) indicating that the application lacks sufficient data to comprehensively assess the effectiveness and safety of this four-dose regimen. This decision does not impact the existing approvals of HEPLISAV-B in the U.S., the European Union, or Great Britain, where it is approved for preventing hepatitis B infection in adults aged 18 and older. Furthermore, the CRL does not affect the recent approval by the European Commission granted in October 2023 for the same four-dose regimen for adults on hemodialysis.

The sBLA submission included clinical immunogenicity and safety data from the Phase 1 HBV-24 study, which involved 119 adults undergoing hemodialysis, along with data from five additional supportive clinical trials in adults with chronic kidney disease or on hemodialysis. The FDA’s CRL highlighted that the data from HBV-24 were inadequate due to the loss of data source documents by a third-party clinical trial site operator for about half of the enrolled subjects. Additionally, the number of subjects in the single-arm HBV-24 study was deemed insufficient to assess the safety of the four-dose regimen conclusively.

Rob Janssen, M.D., Chief Medical Officer of Dynavax, expressed confidence in the data supporting HEPLISAV-B for adult hemodialysis patients. He indicated that all key data collected in the HBV-24 trial had been verified against original source documents during the trial. Janssen also mentioned that Dynavax plans to request a meeting with the FDA to explore options for providing additional data to support the four-dose regimen for this vulnerable patient group in the U.S.

HEPLISAV-B is designed to prevent infection from all known subtypes of the hepatitis B virus in adults aged 18 and older. It is crucial to note that the vaccine should not be administered to individuals who have had a severe allergic reaction to any hepatitis B vaccine or any component of HEPLISAV-B, including yeast. After administration, appropriate medical treatments should be available to address potential anaphylactic reactions. Immunocompromised individuals, such as those receiving immunosuppressant therapy, may exhibit a reduced immune response to the vaccine. Additionally, HEPLISAV-B may not prevent hepatitis B infection in individuals with an unrecognized hepatitis B infection at the time of vaccination.

Common adverse reactions reported within seven days of vaccination include pain at the injection site (23% to 39%), fatigue (11% to 17%), and headache (8% to 17%).

Dynavax is a commercial-stage biopharmaceutical company focusing on developing and commercializing innovative vaccines to protect against infectious diseases. The company’s commercial products include the HEPLISAV-B® vaccine and the CpG 1018® adjuvant, which is used in several vaccines, including those for COVID-19. Dynavax is also advancing the CpG 1018 adjuvant for vaccines targeting shingles, Tdap, and more, through global collaborations.

While Dynavax remains optimistic about its products and ongoing developments, it acknowledges the inherent risks and uncertainties in the biopharmaceutical sector. These include the availability, time, and costs associated with any further studies or trials, the willingness of the FDA to engage in follow-up meetings, and the uncertainty of achieving desired results. The company reiterates that forward-looking statements are subject to change and disclaims any obligation to update information based on new developments.