Heplisav B superior to Engerix-B in Phase III trial for treatment of Hepatitis B- Dynavax

Dynavax Technologies reported preliminary top-line results from HBV-23, a Phase III trial of the safety and immunogenicity of its investigational hepatitis B vaccine, Heplisav-B, compared with a currently marketed vaccine, Engerix-B , in adults 18 to 70 years of age. Heplisav-B participants received two doses, at zero and one month, and Engerix-B participants received three doses, at zero, one and six months. Both co-primary endpoints were met. The rates of clinically significant adverse events were consistent with randomization and similar to rates in prior trials and Heplisav-B provided a statistically significant higher rate of seroprotection than Engerix-B in diabetic participants and in all participants as a group. Safety results from HBV-23- The co-primary endpoint of HBV-23 was to evaluate the overall safety of Heplisav-B with respect to clinically significant adverse events. Participants were randomized to Heplisav-B or Engerix-B in a two to one ratio. Heplisav-B participants were followed for 52 weeks after the last dose and Engerix-B participants were followed for 28 weeks after last dose. All adverse events considered to represent potential autoimmune disorders (Adverse Events of Special Interest, or AESIs) were reviewed by an independent panel of experts from the Mayo Clinic. Preliminary safety evaluation results include: 22 Heplisav-B participants experienced an AESI and 11 Engerix-B participants experienced an AESI. All were classified as not related to vaccination. Of the 33 AESIs in the study, 21 were adjudicated to be autoimmune events by the independent panel, with 11 reported in participants who received Heplisav-B and 10 in participants who received Engerix-B.

Seroprotection results from HBV-23- The co-primary endpoint of noninferiority of seroprotection in participants with diabetes mellitus was met and the greater percentage of seroprotection provided by Heplisav-B compared to Engerix-B was statistically significant. Immunogenicity data from the trial demonstrated- The peak seroprotection rate (SPR) in participants with type 2 diabetes mellitus who received Heplisav-B was 90.0% compared to 65.1% for Engerix-B, demonstrating non-inferiority and a statistically significant higher percentage of seroprotection provided by Heplisav-B compared to Engerix-B.

Comment: Dynavax will re-file its biologics license application with FDA by the end of the first quarter 2016, with the potential for a six month approval cycle.