Heplisav vaccine could offer immunity against hepatitis B in two doses: Dynavax
Dynavax Technologies Corporation has started clinical studies to compare the efficacy of its hepatitis B vaccine Heplisav with GSK’s Engerix-B to see if fewer doses of the vaccine will be sufficient in adult patients.
Currently available hepatitis B vaccines require three doses over six months to achieve full immunogenicity in healthy patient populations. Because compliance with this vaccine regimen is low, new vaccines are needed to provide increased protection in a shorter timeframe.
Furthermore, currently available vaccines do not fully address the needs of several patient populations, including those with chronic kidney disease, HIV or chronic liver disease. In particular, patients with comprised immune systems require both rapid and enhanced protection, either because they are less responsive to conventional vaccine regimens or because they are at high risk of infection, Dynavax stated in a news release.
Heplisav combines hepatitis B surface antigen (HBsAg) with a proprietary Toll-like Receptor 9 (TLR9) agonist to enhance the immune response.
Heplisav has been shown in two pivotal Phase 3 trials to enhance protection more rapidly and with fewer doses than a currently licensed vaccine.
Over 2,500 individuals have been vaccinated with Heplisav to date.
Phase 3 data from PHAST clinical trial demonstrated subjects over 40 years of age receiving two doses of Heplisav over one month achieved a seroprotection rate of 92%, compared to 75% of subjects receiving 3 doses of a licensed vaccine over six months.
The total worldwide market for adult hepatitis B vaccines is estimated at over $500 million annually.
The chronic kidney disease market is large, growing rapidly, and is widely recommended for vaccination.
In 2006, there were approximately 750,000 end-stage renal disease (ESRD) patients in the United States and the 5 major European markets and approximately 150,000 new patients are added annually.
Approximately 35% of these immunocompromised ESRD patients do not respond to vaccination and 20% require boosters. As vaccination for these patients occurs regularly at dialysis centers, this is a highly concentrated, renewable market that can be served by cost-effective, targeted sales distribution networks.
Dynavax has initiated a Phase 3 trial in chronic kidney disease patients and a Phase 3 lot-to-lot consistency trial in adults over 40 years of age.
The lot-to-lot trial is a large-scale trial designed to demonstrate the lot-to-lot consistency of commercial vaccine and to complete the safety database for Heplisav.
The lot-to-lot consistency trial will enroll 2,000 patients in Canada and in the U.S., 1600 of whom will receive Heplisav. Patients randomized to the comparator arm will receive Engerix-B.
The primary objectives are to measure the immune response to Heplisav vaccination and lot-to-lot consistency for immune response of Heplisav.
The secondary objectives include the safety of Heplisav as compared to Engerix-B.
Data from this trial is expected in the first half of 2011.
The hepatitis B surface antigen in the Heplisav lots being evaluated was produced in Dynavax’s manufacturing facility in Duesseldorf, Germany. This facility was recently upgraded and licensed in the European Union for commercial production of hepatitis B surface antigen.
Dynavax has worldwide commercial rights to Heplisav.
Dynavax is a biopharmaceutical company, discovers and develops novel products to prevent and treat infectious diseases.
The company’s lead product candidate is Heplisav.