Precision switching from entecavir to tenofovir alafenamide in chronic hepatitis B: matching the patient phenotype to efficacy, safety, and value: a narrative review.

Switching patients who are virologically stable with chronic hepatitis B from entecavir to tenofovir alafenamide has become routine in Korea; however, the literature has established whether switching works at the population level rather than at the patient level. This review reframes this decision as one of candidate selection. Integrating a 2026 Korean multicenter randomized trial with 2023 to 2025 real-world and pharmacoeconomic data shows that in patients who are fully suppressed, the switch is noninferior and safe but adds little, and the analysis separates evidence generated against tenofovir disoproxil fumarate from the sparser entecavir-controlled evidence on which switching decisions must rest. Five phenotypes with a favorable benefit-risk profile are then defined-low-level viremia or partial virologic response, declining estimated glomerular filtration rate or early tubular injury, bone loss or fracture risk, entecavir or multidrug resistance, and planned or confirmed pregnancy-alongside two conditional situations: decompensated cirrhosis, where routine switching is unnecessary unless renal or bone disease coexists, and high cardiovascular risk, which requires lipid monitoring rather than exclusion. Each phenotype is mapped to the 2026 Korean Association for the Study of the Liver guideline and to Korean reimbursement criteria revised in November 2025, graded for certainty, and consolidated into one algorithm that transfers across health systems because the phenotypes are internationally recognized.