Clearing HBsAg is an important treatment goal and it greatly reduces the risk of liver damage from the infection.
The researchers, reporting in the December issue of the Journal of Gastroenterology and Hepatology,
found that viral load rapidly declined in all patients with entecavir
treatment, with 97.1% achieving undetectable viral load after five
years. Only two patients (representing 1.2% of those studied) developed
resistance to entecavir.
However, "In contrast to the
profound HBV DNA suppression, long-term entecavir treatment only
achieved a slow decline in serum HBsAg," they wrote. "...Additional
therapeutic agents are needed to increase the chance of HBsAg clearance
in chronic hepatitis B."
One-third of patients who respond quickly to entecavir clear HBeAg:
About 31% of hepatitis B "e" antigen (HBeAg-positive) patients who
achieve undetectable HBV DNA after six months of entecavir treatment
will lose HBeAg after two years of treatment, according to a Taiwanese
study published in the December 2013 issue of the Journal of the Formosan Medical Association.
Researchers followed 68
HBeAg-positive patients (75% male, average age 46) and found that 30.9%
of them lost HBeAg after two years of treatment. Patients who
responded well to the antiviral after just six months of treatment and
achieved undetectable HBV DNA usually went on to clear HBeAg within two
years.
Study finds genetics—not drug resistance—is why some patients don't respond to entecavir:
While entecavir is recommended as one of the top, first-line
treatments for hepatitis B, a small percentage of patients respond
slowly to the antiviral.
Researchers have suspected that
some people may harbor virus with mutations that are able to "resist"
entecavir's ability to halt viral replication. However, a study
published in the November 2013 journal Antiviral Therapy, finds that a weak immune system may be the culprit.
Italian researchers analyzed HBV
from five people who responded quickly to entecavir and five who
responded slowly. They found no entecavir-resistant virus in patients
who failed to respond, instead they found a weak immune response
that... "might be at odds in rapidly clearing infected cells from the
liver."
