Background and Objective <p>Efanesoctocog alfa is a first-in-class high-sustained factor VIII therapy approved for prophylaxis, on-demand treatment, and peri-operative management of bleeding in hemophilia A. This analysis aimed to compare the cost effectiveness of efanesoctocog alfa prophylaxis with factor VIII extended half-life prophylaxis.</p> Methods <p>A lifetime Markov model was developed from a US payer perspective, using clinical data from an indirect treatment comparison of phase III studies and inputs derived from the literature. A cohort of patients aged ≥ 12 years with severe hemophilia A without inhibitors, who received prophylaxis using any regimen or on-demand treatment, entered the model. Outcomes included joint and non-joint bleeds, quality-adjusted life-years, total direct costs, and the incremental cost-effectiveness ratio. Costs were expressed in US dollars and inflated to January 2023 prices. Discount rates of 3% were used. One-way probabilistic and scenario analyses were conducted. The willingness-to-pay threshold was assumed at $150,000 per quality-adjusted life-year.</p> Results <p>Efanesoctocog alfa was more effective and less costly (also referred to as ‘dominant’) versus factor VIII extended half-life therapies, with a lower lifetime number of joint (undiscounted 34.00 vs 140.65) and non-joint (undiscounted 13.33 vs 55.99) bleeds, higher quality-adjusted life-years (24.00 vs 22.92), and lower total costs ($30,716,640 vs $32,953,485). A broad range of scenario analyses and probabilistic sensitivity analyses resulted in 100% of simulations being cost effective. Dosing level and drug costs had the largest impact on results in the deterministic sensitivity analyses.</p> Conclusions <p>Our analysis suggests that efanesoctocog alfa was dominant versus prophylaxis with standard and elevated factor VIII extended half-life dosing regimens. Efanesoctocog alfa was associated with better joint health and, hence, contributed to fewer bleeds, lower costs, and higher quality-adjusted life-years.</p>