PB1322 - Emicizumab wastage estimation for treating people with hemophilia A and inhibitors who failed immune tolerance induction according to the current Brazilian public health protocol

Background: Hemophilia A is a bleeding disorder due to deficiency of the clotting FVIII. FVIII replacement is the treatment of choice to treat or prevent bleeding. Up to 30% of individuals may develop inhibitors that neutralize the FVIII clotting effect. To eradicate them, people with hemophilia A and inhibitors (PwHAi) receive immune tolerance induction (ITI). For the approximately 35% of PwHAi who fail ITI, emicizumab is the drug of choice as prophylaxis. In Brazil, the Public Health System (SUS) recently incorporated emicizumab based on a national protocol.

Aims: We aimed to estimate the 1st-year wasting of emicizumab for treatment of PwHAi who failed ITI, in Brazil.

Methods: The Brazilian protocol regimens involve a loading dose of 3.0mg/kg/week for 4 weeks, followed by maintenance doses of 1.5mg/kg/week or 3.0mg/kg/2-week. The monthly dose (6.0mg/kg) is not recommended. Available emicizumab vials contain 30-150mg. We evaluated the first-year wastage (4-week loading followed by 48-week maintenance doses).
According to the Brazilian official recommendation report, 104 PwHAi were eligible to emicizumab prophylaxis. We estimated body weight from the age distribution of PwHAi who failed ITI in the BrazIT Study and the WHO age-related weights (percentiles [P] 15, 50, and 85). Reconstituted, administered, and wasted doses were calculated based on the frequency of PwHAi on each age group, the diverse weight for each age, and the treatment moment.

Results: The total reconstituted costs ranged from US$33,581,495 (biweekly/P15) to US$51,282,689 (weekly/P85). Total wastage ranged from 6.4% (US$2,492,057, biweekly/P50) to 15.5% (US$5,553,728, weekly/P15). The lowest total reconstituted costs (US$31,603,024 for P15) and total wastage (2.1%/US$995,656 for P85) were found on monthly therapy.

Conclusion(s): In conclusion, during the first year of emicizumab prophylaxis drug wastage was not negligible. Alternatives to reduce emicizumab wastage may urgently be implemented to optimize the use of public resource, maintain the SUS sustainability, and guarantee treatment for all the individuals.