No studies have reported the long-term effects of entecavir switching in patients with multidrug resistance who developed resistance after lamivudine/adefovir sequential therapy. We evaluated the efficacy of 96 weeks of entecavir therapy in patients with resistance to lamivudine/adefovir sequential therapy. In total, 33 patients with chronic hepatitis B virus (HBV) infection with evidence of active viral replication (HBV DNA levels ≥ 10(5) copies/mL) or a history of treatment failure to lamivudine/adefovir sequential therapy between April 2007 and July 2009 were treated with entecavir (1.0 mg daily) for at least 48 weeks. The rates of alanine transaminase (ALT) normalization and HBV DNA negativity were 66.7% (14/21) and 24.2% (8/33) at 48 weeks, respectively. The initial HBV DNA level was the only factor that was inversely associated with serum HBV DNA negativity after 48 weeks of entecavir therapy (P < 0.023). At 96 weeks, the rates of ALT normalization and HBV DNA negativity were 77.8% (7/9) and 16.7% (3/18), respectively. Viral breakthrough occurred in 21.2% (7/33) and 78.9% (15/19) of patients at 48 and 96 weeks, respectively. Patients who achieved a HBV DNA level of <4 log(10) copies/mL at 48 weeks maintained a similar HBV DNA level and a normal ALT level until 96 weeks. Entecavir monotherapy for 96 weeks was not efficacious for patients with lamivudine/adefovir-resistant HBV. The initial HBV DNA level was the only predictive factor for antiviral efficacy. However, patients who achieved a HBV DNA level of <4 log(10) copies/mL with a normal ALT level at 48 weeks should maintain, rather than stop, entecavir therapy.

HCV infections are two-times more prevalent in black Americans than in whites. We previously reported that treatment with peginterferon alfa-2a plus ribavirin produced a sustained virologic response (SVR) rate of 26% in blacks, a lower efficacy compared with the SVR in whites. Here we detail the safety profile of peginterferon alfa-2a plus ribavirin and the relationship between treatment adherence, defined by cumulative drug exposure, and SVR in 78 black patients infected with HCV genotype 1. Sixty-two (79%) patients completed 48 weeks of combination treatment. Peginterferon alfa-2a dose was modified for neutropenia in 36 patients (46%), whereas ribavirin dose was modified due to anemia in 31 patients (40%). The SVR rate was related to medication exposure, based on the percentage of the planned doses of peginterferon and ribavirin that the patients received. The SVR rates were 33, 25 and 0% in patients who received >80, 61-80 and 80, 61-80 and 80% of the total planned doses of both peginterferon and ribavirin and 7% (1 of 14) in patients who received 60% exposure to both, and 0% in patients with 60% of the planned peginterferon alfa-2a and ribavirin doses for 48 weeks was associated with a greater SVR in black patients with HCV genotype 1 infections.