Real-world adherence to and persistence with emicizumab in people with hemophilia A using a national claims database.

Abstract

Substantial rates of nonadherence are observed among people with hemophilia A (PwHA) receiving standard- or extended-half-life factor (F)VIII replacement products, although better adherence is associated with fewer bleeding events and better quality of life. Emicizumab is the first bispecific FIXa-/FX-directed antibody approved for routine prophylaxis in PwHA. More real-world adherence and persistence data on emicizumab and other new hemophilia treatments are needed to better inform decisions on population health care and individualized treatments for PwHA. To describe real-world emicizumab adherence and persistence among PwHA in the United States. This retrospective, observational cohort study used adjudicated health plan claims data from IQVIA PharMetrics Plus. This study included PwHA with at least 1 claim noting hemophilia A diagnosis between May 1, 2017, and September 30, 2023; at least 2 claims for emicizumab fills between November 1, 2017, and September 30, 2023; and continuous medical and pharmacy insurance benefit coverage for at least 6 months before and at least 12 months after the first emicizumab fill (index date). Adherence to emicizumab was measured during the 12-month post-index period using the proportion of days covered (PDC). Persistence was defined as the proportion of PwHA who did not discontinue emicizumab during the post-index period, where discontinuation was defined as a treatment gap of at least 60 days. Among adherent PwHA (PDC ≥ 80%), the number of post-index claims for FVIII were evaluated. A total of 280 PwHA were included in the study, of whom 98% were male and the mean age was 26 (SD = 16) years. Overall, 76% of PwHA were adherent to and 85% of PwHA were persistent with emicizumab. Rates of adherence and persistence were high across age- and geography-based subgroups, ranging from 61% to 97%. Among PwHA adherent to emicizumab (n = 213), 57% had no post-index claims for FVIII. In the first year following emicizumab initiation, high adherence and low discontinuation rates were observed among PwHA in a real-world setting.