Treatment Response with Tenofovir-based Combination Therapy in Chronic Hepatitis B Patients with Suboptimal Response to Sequential Entecavir Dosage of 0.5 mg and 1.0 mg Daily

Abstract

Purpose: Entecavir (ETV) is a potent nucleoside with high rates of complete viral suppression (CVS) that is available in two dosage, 0.5 mg and 1.0 mg. However, a significant proportion of patients treated with ETV fail to achieved CVS. Our goal was to examine the treatment outcome with combination therapy in patients who fail to achieve CVS on sequential treatment with ETV 0.5 mg and 1.0 mg daily. Methods: We retrospectively studied 15 consecutive CHB patients who were switched to tenofovir (TDF)-based combination therapy after experiencing suboptimal response with sequential ETV 0.5 mg and 1.0 mg daily between 1/2005 and 9/2010 at two GI clinics in California. Patients were placed on TDF-based combination therapy with ETV 0.5 mg (n=1), or ETV 1.0 mg (n=13), or emtricitabine (n=1). CVS was defined as undetectable HBV DNA PCR (<100 IU/mL). Results: All patients were Asian and 53% were male with a median age of 34 (21-64). All patients had genotype B/C and 93% had detectable hepatitis B e antigen (HBeAg). None of the 15 patients had exposure to another anti-HBV therapy prior to ETV. Median treatment duration with ETV 0.5 mg and 1.0 mg daily were 12 (6-18) months and 12 (12-24) months, respectively. Mean HBV DNA levels (log10 IU/mL) prior to ETV 0.5 mg daily, ETV 1.0 mg daily, and combination therapy were 8.27±0.24, 3.86±0.57, and 3.37±0.53, respectively. No patients had genotypic resistance to ETV. Most patients patients treated with TDF-based combination therapy achieved CVS by week 24 and all by week 48 (Figure 1). No patients achieved HBeAg loss or seroconversion during the study follow-up.Figure: No Caption available.Conclusion: In patients with suboptimal response to both the lower and higher dosage of ETV, most patients had complete viral suppression by week 24 of combination therapy with TDF. Disclosure: Nghiem Ha - No financial relationship with a commercial interest; Nghi Ha - No financial relationship with a commercial interest; Huy Trinh - Consultant: Bristol-Myers Squibb, Grant/Research Support: Gilead Sciences Inc., Roche, Stockholder/Ownership Interest: Gilead Sciences Inc., Bristol-Myers Squibb, Advisory Committee/Board Member: Bristol-Myers Squibb, Gilead Sciences Inc.; Huy Nguyen - Speaker's Bureau: Gilead Sciences Inc.; Khanh Nguyen - No financial relationship with a commercial interest; Kevin Chaung - No financial relationship with a commercial interest.