(223) Fitusiran Prophylaxis Reduces Episodic Treatment-Associated Costs of Managing Breakthrough Bleeds in Hemophilia

Background: : The ATLAS-OLE (NCT03754790) assessed the long-term safety and efficacy of the fitusiran’s antithrombin-based dosing regimen (AT-DR) in people with hemophilia (PwH). This antithrombin (AT)-lowering siRNA therapeutic was compared to clotting factor concentrate (CFC) and bypassing agent (BPA) prophylaxis in a subset of participants.

Objective: : Results from ATLAS-OLE demonstrated that fitusiran AT-DR was associated with reduced CFC/BPA use for breakthrough bleeds management compared to CFC/BPA prophylaxis. This analysis quantifies the potential cost-savings associated with this reduction using ATLAS-OLE trial data.

Methods: : A cost-calculation model was developed in Microsoft Excel including following parameters: episodic treatment doses of CFC/BPA, the number of CFC/BPA doses required to treat a bleed during CFC/BPA prophylaxis, mean body weight, the United States (US) wholesale acquisition costs for CFC/BPA treatment, the administration costs in US healthcare setting, and the reduction in CFC/BPA episodic usage among PwH receiving fitusiran AT-DR. For PwH A without inhibitors, episodic treatments included in the analysis were octocog alfa, efmoroctocog alfa and rurioctocog alfa pegol, while those for PwH B without inhibitors were nonacog alfa, albutrepenonacog alfa and eftrenonacog alfa. For PwH with inhibitors, factor VIII inhibitor bypassing activity (FEIBA) and eptacog alfa were included. The base-case assumed no vial sharing. For each episodic treatment, drug cost per bleed, administration cost per bleed, and combined total cost were calculated for PwH receiving CFC/BPA prophylaxis and for those receiving fitusiran AT-DR. The difference in the costs between CFC/BPA prophylaxis and fitusiran AT-DR was presented as potential cost savings with fitusiran prophylaxis. A scenario analysis assessed the impact of vial sharing.

Results: : Fitusiran AT-DR demonstrated cost savings ranging from $4,039 (efmoroctocog alfa) to $5,801 (rurioctocog alfa pegol) per bleed in PwH A without inhibitors, and $5,247 (nonacog alfa) to $15,262 (albutrepenonacog alfa) per bleed in PwH B without inhibitors. In PwH with inhibitors, fitusiran AT-DR led to savings of $56,802 (FEIBA) to $78,826 (eptacog alfa) per bleed. Scenario analysis considering vial sharing yielded results consistent with the base case.

Conclusions: : Fitusiran AT-DR prophylaxis demonstrated potential for considerable cost-savings in episodic treatment costs for managing breakthrough bleeds in PwH compared with CFC/BPA prophylaxis. Cost-saving benefits appear more pronounced in PwH with inhibitors than in those without inhibitors.

Sponsorship:: Sanofi