Lee HW, et al. - In patients with multidrug-resistant chronic hepatitis B virus (HBV) infections, researchers examined the effectiveness of tenofovir disoproxyl fumarate (TDF) monotherapy and TDF-based combination therapy for viral suppression as rescue therapy by conducting a multicenter, prospective, real-world cohort study. From eight tertiary hospitals in Korea, patients with chronic HBV infection resistant to antivirals were recruited. In total, 174 patients were treated with TDF monotherapy and 249 were treated with combination therapy based on TDF. In the majority of patients with MDR who received TDF monotherapy or TDF-based combination therapy during long-term follow-up, a virologic response (defined as a serum HBV DNA level of <20 IU/mL) was achieved, and the rates were not significantly different. In patients with MDR, long-term use of TDF monotherapy demonstrated non-inferior antiviral efficacy vs that of TDF-based combination therapy.