Evaluation of Lamivudine Resistance Assay Using a Molecular Method in Patients with Chronic Hepatitis B

Objective: Lamivudine is a nucleoside analogue approved by the FDA in 1998 for the treatment of chronic hepatitis B. Its unique disadvantage compared to other antiviral agents used in hepatitis B treatment is the emergence of drug resistance during treatment. In this study, we aimed to determine lamivudine resistant mutations. Materials and Methods: The results of Lamivudine resistance assay were studied in 172 patients with chronic hepatitis B applying to Izmir Tepecik Training and Research Hospital between December 2007 and January 2010. The assay was studied by Multiplex PCR and Reverse Hybridization methods at Izmir Tepecik Education and Research Hospital Infectious Diseases and Clinical Microbiology Laboratory. In our laboratory, RT204, RT180, RT173, and RT80 parameters were searched as resistance parameters. Results: Out of 172 chronic hepatitis B patients, post-treatment lamivudine resistance was found to be positive in 43 patients and negative in 45 patients. Resistance assays were determined to be negative in 82 patients without lamivudine use, and positive in two patients. In this study, the most frequent association was determined to be between rtM204V and rtL180M (8.13%). The second most frequent association was rtM204I and rtL180M with rtL80V (4.65%), and the third most frequent association was found to be between rtM204I and rtL80V mutations (4.06%). Conclusion: Resistance development due to lamivudine used in chronic hepatitis B treatment happens through genes encoding reverse transcriptase enzyme. The most commonly detected mutations are RT 204 and RT 180 mutations. The development of lamivudine resistance limits the use of the drug.