— Christine M. Kukka, Project Manager, HBV Advocate
For years researchers have tried unsuccessfully to
develop a "therapeutic" vaccine using different antigens from the
hepatitis B virus (HBV) in hopes of finding one that would kickstart
the immune system into fighting and eradicating the infection.
Japanese researchers may have
finally found one. In a Phase III clinical trial, they treated 160
hepatitis B patients with either pegylated interferon (a drug currently
used to strengthen the immune system) or the experimental vaccine
containing both the hepatitis B surface antigen (HBsAg) and the core
antigen to see if together they would trigger the immune system to
fight the infection. Current hepatitis B vaccines used to protect
uninfected people contain only the surface antigen to spur production
of surface antibodies.
In the study,
75 people received five courses of the experimental two-antigen
immunization, which was administered by both injection and a nasal
spray over a 10-week period. In the interferon-treated control group,
76 people were treated for 48 weeks, then both groups were followed for
24 weeks after the treatment and immunizations ended.
Researchers
reported that 75 (61%) of patients receiving the vaccine achieved
undetectable viral load (HBV DNA ), and they remained undetectable
during the 24-week follow-up period. Seventy-six patients (67%)
receiving interferon achieved undetectable viral load, however, only
39% remained undetectable 24 weeks after treatment ended.
There were no
dangerous rises in alanine transferase (ALT) levels, signaling liver
damage, in the vaccine-treated group over the study period. "This study
inspired optimism that ongoing protocols of immune therapy against
chronic hepatitis B may be improved by altering (the) nature of
antigens and route of administration," researchers wrote.
CONTROL ID 1734018. A phase
III clinical trial with a therapeutic vaccine containing both HBsAg and
HBcAg administered via both mucosal and parenteral routes in patients
with chronic hepatitis B. (Abstract #923)
Labels: AASLD 2013, therapeutic vaccine