Lamivudine-resistant chronic hepatitis B: an observational study on adefovir in monotherapy or in combination with lamivudine.

Author(s): Gaia S, Barbon V, Smedile A, Olivero A, Carenzi S, Lagget M, Alessandria C, Rizzetto M, Marzano A

Affiliation(s): Department of Gastroenterology and Hepatology, ASO San Giovanni Battista, C.so Bramante 88, 10126 Turin, Italy. silvia.gaia@fastwebnet.it

Publication date & source: 2008-04, J Hepatol., 48(4):540-7. Epub 2008 Jan 31.

Publication type: Comparative Study

BACKGROUND/AIMS: In lamivudine-resistant patients with chronic hepatitis B (CHB), we compared efficacy, predictive response factors and changes in viral mutants in two antiviral approaches with adefovir. METHODS: A prospective cohort study on therapy with adefovir alone (29 patients) or combined with ongoing lamivudine (23 patients) was performed. RESULTS: A virological response was achieved in 55% of patients treated with adefovir and in 83% of those treated with the combination (p>0.05). This response was directly related to the basal viral load (p<0.0001) and obtained in 10 patients with basal HBV-DNA<17,200 IU/ml using both strategies. In patients with a higher basal viral load, the virological response was more frequent when treated with the combination (p<0.05). Mutation at locus rt181 predicted HBV-DNA persistence during therapy. A virological rebound was observed in 18% of non-responders while on adefovir monotherapy. CONCLUSIONS: To achieve a complete virological response and reduce the risk of adefovir-resistant mutants in lamivudine-resistant patients, rescue therapy is preferable at early evidence of genotypic resistance. However, in subjects with a significant viral load, combination therapy is more effective. The presence of the rt181 mutation is associated with incomplete response.