— Christine M. Kukka, Project Manager, HBV Advocate
The antiviral tenofovir (Viread) is considered the most powerful
antiviral currently on the market with the lowest rate of drug
resistance, even after five years of use.
But tenofovir may have met its match in a patient
who had already developed resistance to the antivirals lamivudine
(HBV-Epivir), adefovir (Hepsera) and entecavir (Baraclude) before
trying tenofovir.
According to a report by Korean researchers published in the April issue of the Journal of Clinical Virology,
the 54-year-old man with HBeAg-positive hepatitis B was treated with
tenofovir after unsuccessful treatment with lamivudine, followed by
entecavir, and then a combination of adefovir and lamivudine.
The man developed various mutations in his HBV
that were able to evade these antivirals that target certain areas of
the virus to stop replication. When he finally tried tenofovir, the
various mutations he had developed were enough to render even tenofovir
ineffective.
"Tenofovir resistance may emerge due to
multi-site polymerase (multiple) mutations rather than (a) single-site
polymerase mutation," the researchers wrote.
Source: www.ncbi.nlm.nih.gov/pubmed/24836314
HBV Journal Review — June 1, 2014, Vol 11, no 6 Labels: drug resistance, tenofovir
