Simple Scoring System Predicting Genotypic Resistance During Rescue Therapy for Lamivudine-Resistant Chronic Hepatitis B

GOALIn this study, we aimed to devise a simple scoring system predicting the risk of genotypic resistance (GR) to current rescue therapies for patients with lamivudine (LAM)-resistant chronic hepatitis B. BACKGROUNDLAM and adefovir (ADV) combination therapy should be recommended for an initial rescue therapy against LAM-resistant hepatitis B virus (HBV). However, there still are many LAM-resistant patients being treated with entecavir (ETV) or ADV monotherapy. STUDYThis retrospective cohort study included consecutive patients treated for LAM-resistant chronic hepatitis B with ETV or ADV monotherapy, or LAM/ADV combination therapy. The cumulative probabilities of GR and virological responses and breakthrough according to clinical variables were analyzed by survival analyses and derived an index for future GR. RESULTSA total of 224 patients were included (median treatment duration=117.9 wk). Using risk factors indentified on multivariable analyses, a simple index for future GR (Antiviral Resistance Prediction Index, ARPI) was developed with 3 clinical variablesthe rescue therapy regimens (+0, ADV; +1, ETV; +2, LAM/ADV), HBV DNA reduction at 12 weeks (+0, 3 log10 copies/mL), and the initial HBV DNA level (+0, >10 copies/mL; +1,