— Christine M. Kukka, Project Manager, HBV Advocate
Experts know some hepatitis B virus (HBV) strains called genotypes
respond better to interferon treatment than others, but now scientists
are discovering that genotypes respond differently to antiviral
treatment too.
HBV genotypes are found in different regions of
the world and each evolved over centuries to have slightly different
molecular make-ups with unique traits. Some carry a higher risk of
liver damage and cancer, while other genotypes are less virulent.
In a recent study, Italian researchers compared
how well patients with genotypes A, D and E fared after three years of
treatment with the antiviral entecavir (Baraclude). All of the patients
tested negative for the hepatitis B "e" antigen (HBeAg-negative). The
scientists measured hepatitis B surface antigen (HBsAg) levels and HBV
DNA (viral load) every three months during the first year of treatment
and then every six months over the study period.
They found the rates of HBsAg declines resulting
from antiviral treatment varied markedly between genotypes. They
extrapolated how many years of entecavir treatment each genotype
required before a patient would clear HBsAg and achieve undetectable
viral load.
HBV genotype A: It would take on
average 15.6 years of entecavir treatment for an HBeAg-negative
patient with HBV genotype A to lose HBsAg. This genotype is found in
northern Europe, North America, India and southern Africa.
HBV genotype D: It would take 17
years for genotype D patients to lose HBsAg. This strain is found
primarily in Russia, the Middle East, the Mediterranean region, and
India.
HBV genotype E: This genotype,
found in Central Africa, responded the most poorly to entecavir.
Scientists estimated it would take 24.6 years for these patients to
lose HBsAg, according to the report published in the August issue of
the Journal of Medical Virology.
Source: www.ncbi.nlm.nih.gov/pubmed/25131947
http://www.hbvadvocate.org/news/HBJ11.9.htm
Labels: entecavir, Genotype E
