Switch From Adefovir to Tenofovir in Chronic Hepatitis B for Suboptimal Response to Adefovir-based Combination Therapy

Overview

In Korea, the number of suboptimal responders to rescue combination therapy is also increasing. As a matter of fact, according to the investigations in Korea, HBV DNA undetectability at 48 weeks of adefovir and lamivudine combination rescue therapy for patients with lamivudine resistance was reported to be only 32.4%, which suggested that the appropriate another rescue therapy might be urgently required. However, there is no promising oral antiviral agents to control these patients in Asia-Pacific region, where tenofovir is not widely available. Tenofovir has a higher potent antiviral efficacy and a negligible drug resistance rate. The switch from adefovir to tenofovir in patients who have insufficient hepatitis B virus (HBV) suppression (HBV DNA ≥ 60 IU/mL by PCR) may lead to increased viral suppression or more HBeAg loss/seroconversion. Here, the investigators aimed to conduct a randomized study on evaluating the antiviral efficacy, safety, and tolerability of switching from adefovir to tenofovir in chronic hepatitis B patients who have suboptimal response to adefovir-based combination rescue therapy due to nucleoside analogues Resistance (SATIS study).

The major goal of antiviral therapy against chronic hepatitis B is to suppress viral replications successfully, ultimately preventing the chronic liver damage, development of liver cirrhosis and hepatocellular carcinoma. In Korea, the number of multi-drug resistant CHB has been rapidly increased last few years. It is because that the national health insurance coverage is very limited for the patients who experienced primary treatment failure. The only switch to adefovir has been allowed in lamivudine resistant patients and thus this sequential rescue therapy generated multi-drug resistance to both adefovir and another drugs. Thus, nowadays, add-on therapy rather than switch therapy might be preferred from major guidelines in this point. However, the number of suboptimal responders to rescue combination therapy is also increasing. As a matter of fact, according to the investigations in Korea, HBV DNA undetectability at 48 weeks of adefovir and lamivudine combination rescue therapy for patients with lamivudine resistance was reported to be only 32.4%, which suggested that the appropriate another rescue therapy might be urgently required. However, there is no promising oral antiviral agents to control these patients in Asia-Pacific region, where tenofovir is not widely available. Tenofovir has a higher potent antiviral efficacy and a negligible drug resistance rate. It belongs to the different class compared to other oral nucleoside analogues (NAs) such as lamivudine, telbivudine, clevudine and entecavir. The switch from adefovir to tenofovir in patients who have insufficient hepatitis B virus (HBV) suppression (HBV DNA ≥ 60 IU/mL by PCR) may lead to increased viral suppression or more HBeAg loss/seroconversion. The results of this study will provide a rationale for switch from adefovir to tenofovir in combination to another drug continued (lamivudine, telbivudine, clevudine and entecavir). Here, the investigators aimed to conduct a randomized study on evaluating the antiviral efficacy, safety, and tolerability of switching from adefovir to tenofovir in chronic hepatitis B patients who have suboptimal response to adefovir-based combination rescue therapy due to nucleoside analogues Resistance (SATIS study).