BACKGROUND The efficacy and safety of switching from tenofovir disoproxil fumarate-based antiretroviral therapy to coformulated elvitegravir, cobicistat, emtricitabine, and tenofovir alafenamide (E/C/F/TAF) has not been widely investigated in HIV/hepatitis B virus (HBV)-coinfected Asian population. METHODS Between February and October 2018, HIV/HBV-coinfected patients who had achieved HIV viral suppression with tenofovir disoproxil fumarate-containing regimens were switched to E/C/F/TAF. Assessments of plasma HBV and HIV viral load, HBV serology, renal function, lipid profiles, and bone mineral density (BMD) were performed at weeks 24 and 48 after switch. RESULTS A total of 274 HIV/HBV-coinfected participants were enrolled, with 12.8% testing HBeAg-positive and 94.2% having plasma HBV DNA