Prophylactic Treatment in People with Severe Hemophilia B in the US: An Analysis of Real-World Healthcare System Costs and Clinical Outcomes
Authors: Noone Declan , Pedra Gabriel , Asghar Sohaib , O'Hara Jamie , Sawyer Eileen K , Li Nanxin (Nick) 
Published: November 2019

Introduction
The treatment paradigm for people with severe hemophilia B in the US typically involves prophylaxis with factor IX (FIX) replacement therapy, the primary aim of which is to provide sufficient FIX levels to reduce the frequency of bleeding events. The clinical benefits of FIX prophylaxis are well understood, however the cost of FIX products as well as costs associated with healthcare resource utilization present a significant burden to the healthcare system. Substantive costs may also accrue in patients who continue to bleed while on prophylaxis, due to the impact on both short and long-term joint-related outcomes. In the absence of existing data in the US, the 'Cost of Hemophilia Across the USA: a Socioeconomic Survey' (CHESS US) study was conducted to establish a population-based estimate of the real-world US healthcare system burden associated with severe hemophilia.
Using data drawn from the CHESS US study, this analysis examines the real-world healthcare system costs and clinical outcomes of people with severe hemophilia B on FIX prophylaxis.
Methods
CHESS US, a retrospective, cross-sectional dataset of adults with severe hemophilia in the USA, gathered information on patient cost via a patient record form. Data on the following parameters are included in this analysis: FIX consumption, annualized bleeding rate (ABR), the presence of one or more chronically damaged joints ("problem joint"), as well as costs associated with annual (prophylactic) factor consumption and hospitalizations (i.e., number of admissions, number of day cases, total inpatient days, and total intensive care unit [ICU] days). All variables report retrospective data of the 12 months prior to enrolment in the study. Results are presented as mean (± standard deviation) or N (%).
Results
In total, 132 of 576 patients profiled in the CHESS US study had severe hemophilia B. Among them, 77 patients were on FIX prophylaxis, of whom 44 patients reported FIX dosing regimen and were included in the current analyses. Among them, 20 patients were treated with conventional FIX and 24 patients with extended half-life (EHL) FIX products. The cohort has a mean age of 27.64 (± 11.05) and mean weight (kg) of 75.71 (± 13.41). In the last 12 months, the mean number of international units (IU) prescribed for FIX prophylaxis across the full cohort was 257,216 IU (± 213,591), with an associated annual cost of $610,966 (± $495,869). Among patients treated with conventional FIX, mean prescribed FIX was 287,141 IU (± 264,906) at an annual cost of $397,491 (± $359,788), while patients treated with EHL FIX reported a mean prescribed FIX of 232,278 IU (± 160,914) at an annual cost of $788,861 (± $529,258).
The cohort reported a mean ABR of 1.73 (± 1.39); 8 (18%) were reported to have a target joint meeting the International Society on Thrombosis and Haemostasis (ISTH) definition; and 11% were reported to have had at least one chronically damaged joint (i.e., problem joint). Healthcare resource utilization associated with bleed events were reported as follows: hospital admissions days [0.18 (± 0.62)]; inpatient days [0.34 (± 1.22)]; and ICU days [0.23 (± 0.86)]. The direct medical cost to the healthcare system was $2,885 (± $7,857; excluding FIX cost) and $614,886 (± $498,839; including FIX cost).
Discussion
Data from the CHESS US study showed substantial costs and resource utilization among patients with severe hemophilia B receiving FIX prophylaxis, of which the cost of FIX replacement therapy constituted most of the total cost to healthcare system. Although the ABR observed in the analysis population was low, bleed-related hospitalizations comprised a significant non-drug cost to the healthcare system. A proportion of patients also still experienced joint arthropathy. Such substantial clinical and economic burden highlights that unmet needs remain in patients with severe hemophilia B on FIX prophylaxis in the US.

Disclosures
Noone: HCD Economics: Employment. Pedra:HCD Economics: Employment. Asghar:HCD Economics: Employment. O'Hara:HCD Economics: Employment, Equity Ownership. Sawyer:uniQure Inc.: Employment. Li:uniQure Inc.: Employment.