Adefovir

Lamivudine had been widely used for treatment-naïve chronic hepatitis B patients. However, development of antiviral resistance has been known as the major drawback: Incidence of lamivudine resistance was reported to be approximately 70% after 5 years (Lok AS et al, 2003). For the treatment of lamivudine resistance, adefovir has been widely used (Lok AS and McMahon B, 2009). However, switching to adefovir monotherapy was also reported to be at high risk of resistance, 25% at year 2 (Yeon JE et al, 2006). Recently, adding adefovir on lamivudine was shown to be superior to switching to adefovir monotherapy by decreasing the adefovir resistance (Rapti I et al, 2007, Lampertico P et al, 2007). However, combination of adefovir and lamivudine does not increase antiviral activity compared with adefovir monotherapy in patients with lamivudine resistance (Peters MG et al, 2004). As many patients are still viremic with the treatment of lamivudine and adefovir over 1 year, the investigators need more potent combination of the drugs. Telbivudine is a new nucleoside analogue with potent antiviral activity. The previous phase III study has shown the superiority of telbivudine over lamivudine in HBeAg positive and negative subjects (Lai CL et al, 2007). Therefore, telbivudine plus adefovir may be a better treatment option than lamivudine plus adefovir for the lamivudine-resistant chronic hepatitis B patients. No study assessing the efficacy of telbivudine plus adefovir has been conducted for these patients. The aim of this study is to evaluate the safety and efficacy of telbivudine plus adefovir compared with lamivudine plus adefovir in lamivudine resistant chronic hepatitis B patients at the end of 1 year follow-up,