Tenofovir disoproxil fumarate in Asian or Pacific Islander chronic hepatitis B patients with high viral load (≥ 9 log10 copies/ml)

Background & AimsWe evaluated the antiviral response of Asian or Pacific Islander (API) patients with chronic hepatitis B (CHB) who had baseline high viral load (HVL), defined as pre-treatment hepatitis B virus (HBV) DNA 9 log(10) copies/ml, following up to 288weeks of tenofovir disoproxil fumarate (TDF) treatment. MethodsA total of 205 HBeAg-negative and HBeAg-positive self-described API patients received 48weeks of TDF 300mg (HVL n=18) or adefovir dipivoxil 10mg (HVL n=15) in a blinded fashion, followed by open-label TDF for an additional 240weeks. The proportions of HVL vs. non-HVL patients with HBV DNA <400 copies/ml were compared. Mean declines in HBV DNA were evaluated in API vs. non-API patients. ResultsThroughout the first 72weeks of treatment, a smaller proportion of HVL API patients reached HBV DNA <400 copies/ml than non-HVL API patients. However, after this timepoint similar proportions of HVL and non-HVL API patients achieved HBV DNA <400 copies/ml (100% vs. 97%, respectively), which was maintained through week 288, where 92% of HVL patients and 99% of non-HVL API patients on treatment had HBV DNA <400 copies/ml. During the 288weeks of treatment, API patients had similar mean HBV DNA declines as non-API patients, regardless of whether patients were HVL or non-HVL. No API HVL patient had persistent viremia at week 288. No resistance was detected among HVL or non-HVL patients. ConclusionsAPI patients with HVL CHB achieve HBV DNA <400 copies/ml with long-term TDF treatment; however, achieving viral suppression may take longer for HVL patients relative to non-HVL API patients.