Background Gemtuzumab ozogamicin (GO) was approved in 2017 in the US for the treatment of adults with newly diagnosed CD33-positive (CD33+) acute myeloid leukemia (AML), and adults and pediatric patients with CD33+ relapsed/ refractory (R/R) AML. Objective The aim of this study was to estimate the budgetary impact of introducing GO to a 1-million-member US health plan over a 5-year period. Methods We developed models to estimate the impact of introducing GO in combination with conventional induction chemotherapy or as monotherapy for newly diagnosed AML, and as monotherapy for R/R AML. Models were built using data on drug costs and treatment-related outcomes obtained from published clinical trials and other publicly available sources. Results were reported on a per member/per year and per member/per month (PMPM) basis. Results Base-case results of the newly diagnosed model indicated that the addition of GO in the combination setting reduced the overall budget of a 1-million-member health plan. The estimated net cost