Centre national de référence des hépatites B, C et delta, laboratoire de virologie, Inserm U955, hôpital Henri-Mondor, université Paris-XII, 8, avenue du Général-Sarrail, 94000 Créteil, France
Chronic hepatitis B therapy is aimed at improving quality of life and survival by preventing liver disease progression and the onset of complications. To achieve this goal, viral replication must be potently inhibited on the long-term. The assessment of treatment response is based on repeated measurements of serum aminotransferase levels and HBV DNA levels by means of a real-time PCR assay with a lower limit of detection of 10-15 international units per milliliter (IU/mL). Complete, sustained inhibition of HBV replication, HBe seroconversion and HBs antigen (HBsAg) loss (with or without HBs seroconversion) are the endpoints of chronic hepatitis B treatment. The EASL Clinical Practice Guidelines on the management of chronic hepatitis B recommend assessing serum aminotransferase and HBV DNA levels three months after the start of therapy and then every three to six months. If HBV DNA is still detectable at 48 weeks of therapy, there is a risk for resistance development. Resistance must be suspected in case of an increase of HBV DNA level of at least 1 Log
10 or an HBV DNA that becomes detectable after having been undetectable in a compliant patient. The presence of resistance substitutions can be assessed. New tests, such as HBsAg quantification or HBe antigen (HBeAg) quantification in serum, or cccDNA quantification in liver biopsies, are available or in development and could find an indication in future clinical practice.