The application dimension of the Entecavir market is divided into three primary segments that together define the overall market size. Treatment‑naïve chronic HBV patients represent the largest share, accounting for roughly 45 % of global demand, as first‑line therapy is recommended by most clinical guidelines. This cohort drives volume growth through high prescription rates and long‑term adherence. The second segment, treatment‑experienced chronic HBV patients, contributes about 35 % of the market; these patients switch to Entecavir after suboptimal response or resistance to other nucleos(t)ide analogues, generating incremental sales from rescue therapy and higher dosage utilization. The third segment, pediatric HBV prophylaxis, comprises approximately 20 % of the market, reflecting the increasing emphasis on early viral suppression in children born to infected mothers. Collectively, these application categories form the core of Entecavir segmentation, with each segment’s clinical prevalence and treatment duration directly influencing revenue streams and forecasting models.