Adults with severe hemophilia B experience persistent number of bleeds per year, as well as joint problems and mild to moderate chronic pain, pointing to an unmet medical need in these patients, according to actual data from the European CHESS study II.
The study, “Clinical, humanistic, and economic burden of severe hemophilia B in adults receiving factor IX prophylaxis: results from the CHESS II real-world burden of disease study in Europewas published in the Orphanet review of rare diseases.
Because hemophilia B is four to five times less common than hemophilia A, real-world studies focused on assessing the current burden of severe hemophilia B are still limited.
To better understand the clinical and economic burden of severe hemophilia B in Europe, a team of researchers from uniQure, along with colleagues from HCD Economics and the University of Chester, analyzed data from the CHESS II study .
CHESS II investigated the burden of disease in adults with severe haemophilia A or B in the UK and seven other European countries: Denmark, France, Germany, Italy, the Netherlands , Romania and Spain.
Specifically, they analyzed retrospective data, collected from 2019 to 2020, from patients with severe haemophilia B from France, Germany, Italy, Spain and the UK.
Patients had not developed inhibitors of FIX – neutralizing antibodies that target therapies intended to replace FIX, the clotting factor missing in patients with hemophilia B – at the time of data collection and were being treated with standard (SHL) or extended half-life (EHL) replacement therapies as a preventive measure.
The analysis included both clinical, human and economic outcomes reported by patients and physicians. Participants completed questionnaires on bleeding, joint status, quality of life, and direct and indirect costs related to hemophilia.
In total, they looked at data from 75 patients with hemophilia B, including 42 (56%) treated with SHL and 33 (44%) with EHL. Patient-reported outcomes were available for 40 (53%) patients.
Most patients (70%) had two or more bleeding events per year, with an average annualized bleeding rate (ABR) of 2.4. The ABR was similar for patients receiving EHL or SHL preventive treatment (2.5 versus 2.4).
The proportion of patients with a history of joint surgery was also similar for those receiving EHL or SHL replacement therapy (33% versus 24%, respectively).
However, a greater proportion of patients receiving EHL reported having at least one target joint (30% versus 17%). Target joints were defined as joints where three or more bleeds occurred over a six-month period.
More than three-quarters of patients reported mild or moderate chronic pain (76%). In addition, most patients (63%) said that hemophilia had an impact on their daily life and 20% said that they had to adapt their treatment regimen before physical activity.
The average annual medical costs due to hemophilia per patient were €235,723 (about $262,430). Most of these costs were driven by FIX treatment costs, which totaled €232,328 (approximately $258,650). Costs were higher for EHL (€290,620 or approximately $323,547) than for SHL (€186,528 or approximately $207,661).
The costs of FIX treatment varied considerably between countries, with the highest costs seen in Germany (€393,263, or approximately $437,820) and the lowest in the UK (approximately €182,219, i.e. approximately $202,864). The average annual indirect costs (€8,973 or $9,995) were related to early retirement or the need to stop working due to haemophilia.
Patients had an average score of 0.67 on the 5 European Quality of Life Dimensions (EQ-5D), a standardized measure of overall health and quality of life. Its scores range from zero (worst possible state) to one (best possible state of health).
Taken together, these real-world data “demonstrate the substantial clinical and humanistic burden of severe hemophilia B, as well as an ongoing economic burden,” despite preventive treatment, the researchers wrote.
Moreover, according to the researchers, these results highlight the “persistent unmet needs of these patients, their caregivers and society.”