1University of Toronto, Ontario, Canada.
BACKGROUND & AIMS:
We 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 log10 copies/mL, following up to 288 weeks of tenofovir disoproxil fumarate (TDF) treatment.
A total of 205 HBeAg-negative and HBeAg-positive self-described API patients were randomized to receive 48 weeks of TDF 300 mg (HVL n=18) or adefovir dipivoxil 10 mg (HVL n=15) in a blinded fashion, followed by open-label TDF for an additional 240 weeks. The proportions of HVL versus non-HVL patients with HBV DNA <400 copies/mL were compared. Mean declines in HBV DNA were evaluated in API versus non-API patients.
Throughout the first 72 weeks 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% versus 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 288 weeks 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.
API 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.