Prediction of breakthrough hepatitis due to lamivudine-resistant hepatitis B virus by a sensitive semiquantitative assay using peptide nucleic acids

• Published in: Intervirology Vol. 49; no. 5; p. 274
• Main Authors: Mori, Kojiro, Minami, Masahito, Kirishima, Toshihiko, Kunimoto, Koji, Okita, Mika, Nakayama, Mika, Makiyama, Akiko, Yamaoka, Junko, Nakajima, Tomoki, Yasui, Kohichiroh, Itoh, Yoshito, Okanoue, Takeshi
• Format: Journal Article
• Language: English
• Published: Switzerland 01-01-2006
• Subjects: Adult; Aged; DNA Mutational Analysis; Drug Resistance, Viral - genetics; Female; Hepatitis B virus - drug effects; Hepatitis B virus - genetics; Hepatitis B, Chronic - drug therapy; Hepatitis B, Chronic - virology; Humans; Lamivudine - pharmacology; Lamivudine - therapeutic use; Male; Middle Aged; Mutation; Peptide Nucleic Acids; Polymerase Chain Reaction - methods; Reverse Transcriptase Inhibitors - pharmacology; Reverse Transcriptase Inhibitors - therapeutic use; Time Factors
• ISSN: 0300-5526
• DOI: 10.1159/000093457

The aim of this study was to predict breakthrough hepatitis and analyze the dynamics of lamivudine-resistant hepatitis B virus in patients treated with lamivudine.
Fifty-five chronic hepatitis B patients treated with lamivudine were included. The emergence of YMDD motif mutants was detected by peptide nucleic acid (PNA) mediated PCR clamping with a detection limit of 10(1) YMDD mutants. We then performed a semiquantitative PCR assay of subjects in whom YMDD mutants were detected. This assay detects 10(2.7)-10(7.7) copies of mutant virus per 1 ml of serum.
YMDD mutants were detected in 28 (51%) of the 55 patients. Eight patients stopped medication before viral breakthrough. YMDD mutants appeared transiently despite the continuance of lamivudine therapy in 12 patients. In all 8 patients with breakthrough hepatitis, the quantities of YMDD mutants ranged from 10(2.7)-10(4.7) copies/ml in the two to three months before clinical breakthrough. In contrast, in 12 patients without viral breakthrough, there were always less than 10(2.7) copies/ml YMDD mutants.
Lamivudine-resistant viruses sometimes disappear even during lamivudine administration. Our sensitive quantitative assay proved useful for early detection of YMDD mutants and a threshold of 10(2.7) copies/ml is suggested for predicting viral breakthrough.