FDA Issues Complete Response Letter for HBV Vaccine

The FDA has recently issued a complete response letter to Dynavax Technologies Corporation regarding their biologics license application for HEPLISAV-B (hepatitis B vaccine, recombinant [adjuvante]).

The complete response letter indicates that the FDA has completed a review of the application, and is now requesting additional information from the company in order to move forward with additional reviews and approval.

Dynavax is expecting to receive a class 2 designation once they resubmit the biologics license application, which results in a review period of 6 months, they reported in a press release.

The complete response letter is seeking additional information about specific adverse events of special interest, a numerical imbalance in cardiac events in the HBV-23 clinical trial, new analyses of safety data during different times, and commitments after the drug is launched.

The FDA also indicated that they have not completed the review of responses they received from Dynavax in October, which includes information about the aforementioned adverse events of special interest and the imbalance in cardiac events, according to Dynavax.

The responses previously submitted included an in-depth analysis conducted through an outside consultation. The consultation concluded that the imbalance was due to an unexpectedly small amount of events in the comparison group.

The FDA did not ask for additional clinical trials in the complete response letter, and they also did not discuss any concerns with serious autoimmune adverse events associated with the vaccine.

Hepatitis B virus is a chronic liver disease that can lead to serious complications if left untreated, such as cirrhosis, hepatocellular carcinoma, and death. Current hepatitis B virus vaccines are administered in 3 doses over 6 months, and only approximately 54% of adults completed the series of vaccines.

HEPLISAV-B is an investigational vaccine that enhances the immune response by combining the hepatitis B surface antigen with a Toll-like receptor 9 agonist, according to Dynavax. The vaccine is administered in 2 doses over a 1-month period, which could improve adherence.

Despite the complete response letter (CRL), Dynavax is committed to making this vaccine available to individuals who are at risk of hepatitis B virus.

“The CRL is consistent with our opinion that HEPLISAV-B is approvable and we are seeking to meet with the FDA as soon as possible,” said Eddie Gray, chief executive officer of Dynavax. “However, the time and resources that will be required to gain approval leads us to consider that we may not be able to advance this program on our own and we are moving swiftly to identify a potential pharmaceutical or financial partner. We will maintain our efforts on the oncology programs, including our lead cancer immunotherapy candidate, SD-101, for which we recently announced encouraging early clinical data in metastatic melanoma.”