Lamivudine Resistance in Iranian Chronic Hepatitis B Patients.

Background and objectives: Lamivudine therapy for chronic hepatitis B (CHB) is associated with resistance. This study aimed to analyze the response, the incidence of LAM resistance, and different viral mutational patterns of Lamivudine therapy. Study design: CHB patients (n=31) who had not previously received interferon or a nucleoside analogue, received Lamivudine once daily for a minimum of E12 months and followed. All patients were tested for presence of mutation in YMDD motif of viral polymerase gene at the end of the first year of treatment, and if indicated in rising alanine aminotransferase (ALT) or HBVDNA titer. Polymerase chain reaction along with restriction fragment length polymorphism (PCR-RFLP) method was used to detect mutations in YMDD motif. Results: The mean age of patients was 45.2 (SD 13.5) years. The mean follow-up period of patients was 45.5 (21.9) months. Seventeen patients (54.8%) had mutations, and 45.2% of subjects were sensitive to LAM. Mean time of mutation detection after treatment was 45.5 (SD 25.3) months. The distribution of YMDD status was: 32.3 % YIDD, 3.2% YSDD, 12.9% YVDD, and 6.5% YVDD/ YIDD. The mean age, pretreatment HBeAg negativity, and high HBVDNA titer at time of mutation had significant statistical association with occurrence of YMDD mutants (PV= 0.009, 0.032, 0.049), respectively. Conclusions: Lamivudine-resistant mutation is common in CHB patients. Regarding different mutant strains as identified in this study, is necessary for develop more useful treatment strategies, especially in patients without YMDD mutation and high HBVDNA titer, analysis for possible new mutants should be performed.