Clinical

Hepatitis B genotype A predicts poor response to lamivudine

Last Updated: 2006-10-31 14:55:13 -0400 (Reuters Health)

NEW YORK (Reuters Health) - Among patients with Hepatitis B, response to lamivudine antiviral therapy is strongest among those with genotype B virus and poorest among those with genotype A, Japanese researchers report in the October issue of the Journal of Medical Virology.

Dr. Mariko Kobayashi and others at Toranomon Hospital in Tokyo studied response to lamivudine among 502 patients with hepatitis B virus infections. Fifteen patients had genotype A, 38 had genotype B and 449 had genotype C.

Median age of patients with genotype A was 37 years, compared with 47 years for genotype B and 44 years for patients with hepatitis B genotype C.

Hepatitis B e antigen (HbeAg) was present in 73% of patients with genotype A, in 21% with genotype B and in 56% with genotype C.

Hepatitis B DNA levels were higher in genotype A patients at 8.6 log genome equivalents (LGE)/mL, compared with 6.5 LGE/mL in patients with genotypes B and C.

Breakthrough hepatitis occurred in 47% of genotype A patients, compared with 21% of genotype B and 29% of genotype C patients. Genotype was a risk factor for hepatitis breakthrough only among patients who were HbeAg-positive.

YMDD mutants developed more often in genotype A patients compared with genotypes B and C. HBeAg seropositivity increased the risk of development of YMDD mutants.

"A therapeutic option for patients with genotype A who respond poorly to long-term lamivudine treatment may include adefovir dipivoxil that has a high efficacy unaccompanied by drug resistant mutants in patients with or without HbeAg," the investigators advise.

J Med Virol 2006;78:1276-1283.