Background: Dolichyl (Dol), the main lipid intermediator of Dolichyl Phosphate Cycle (DPC) has been reported to be elevated in urine of patients with multidrug resistance in cancer. Drug resistance poses a major threat to nucleoside analogue-based therapies for chronic HBV infection. Methods: With focus on a risk predictor for susceptibility to the development of HBV drug resistance the present study was carried out to estimate urinary levels of Dol in chronic HBV infection. The samples obtained every week before and during the course of treatment from 42 patients with HBV. The occurrence of exacerbations of chronic HBV were registered for 2 years. Dol in urine was assayed by HPLC method. Results: The normal amounts of Dol in healthy persons urine (n=1500) are 6,0 + 10,0 mkg/mmol creatine. During the period of observation 36 (86%) of patients treated with nucleoside analogue-based therapies were diagnosed with exacerbations due to resistance of hepatitis B virus to antiviral drugs. From this group of HBV patients 35 (98%) have had elevated urinal Dol excreation (45,8±5,2 g/ml vs . 8,2±1,9 g/ml, p<0.0001) in more than 3 months of observation. Conclusion: There is a reason to suggest that elevated urinal Dol detected in patients with exacerbations during HBV treatment may evidence of possible defect of host mechanism of drug resistance development to nucleoside analogue-based therapies. The interest drawn to the employment of Dol as a predictor for exacerbation of chronic HBV is explained by the role of DPC in P-glycoprotein regulation in human hepatocytes. Background: A significant proportion CHB patients treated with ADV have a suboptimal response, increasing the risk of disease progression and development of resistance. We report clinical results from patients who either failed or relapsed following ADV therapy and were subsequently switched to ETV. Methods: Study ETV-079 was a randomized, open-label study comparing antiviral efficacy of ETV (0.5mg/day) vs ADV (10mg/day) in nucleoside-naïve HBeAg-positive patients. After up to 96 weeks of treatment in ETV-079, 24 patients treated with ADV (13 suboptimal responders) rolled over into study ETV-901 (1.0mg/day). HBV DNA viral suppression and safety was evaluated during 48 weeks of ETV treatment. Results: At entry to ETV-901, the median HBV DNA was 5.72log10 copies/mL. Median exposure to ETV (1.0mg) in ETV-901 was 46 weeks and 18 patients currently remain on study therapy. At Week 24, the mean reduction in HBV DNA was 4.5log10 copies/mL and 8/16 (50%) reached HBV DNA levels <300 copies/mL. Nine patients have achieved Week 48 and all have achieved HBV DNA <10 4 copies/mL and 8/9(89%) had HBV DNA levels <300 copies/mL. No patients experienced virologic breakthrough on ETV. The safety profile of ETV in ADV-treated patients remained consistent with the previously reported experience. Conclusions: The majority of patients who were suboptimal responders or virologic rebounders following ADV treatment in study ETV-079, experienced rapid reductions in HBV DNA levels when switched to ETV. HBV DNA levels continued to decline to undetectable levels with 48 weeks of ETV treatment.