Real-world experience on the use of rIX-FP in patients with haemophilia B: Interim results from a prospective, non-interventional, post-market surveillance study in Germany

Objective The phase 3 extension study with rIX-FP, a long-acting fusion protein, has demonstrated low annualised bleeding rates in patients with haemophilia B treated with rIX-FP prophylaxis. rIX-FP enables treatment to be tailored to the needs of individual patients, with dosing flexibility allowing selected patients to be treated with prophylaxis intervals of 7, 10, 14 or 21 days. Data on the use of rIX-FP in routine clinical practice are required. Prospective, non interventional, multicentre studies are ongoing to gather data on efficacy, safety and health-related quality of life outcomes in patients treated with rIX FP during routine clinical practice in Europe.

Material and Methods A non-interventional study in Germany was initiated in March 2018; all patients with haemophilia B were eligible for enrolment. Patients are treated prophylactically with rIX-FP with dosing regimens up to every 14 days and undergo routine monitoring every 3–12 months. Patients are followed for 2–3 years or until 100 exposure days. Patient data is collected, stored and pseudonymised in accordance with General Data Protection Regulations.

Results As of May 2020, 52 patients across Germany were enrolled in the study; the majority of patients have moderate or severe haemophilia B. Patients range in age from 1–80 years and have between 0 and 343 exposure days to rIX-FP. At this point, 22 adverse events were recorded in this cohort, none of which were considered related to rIX-FP, and no patients have developed inhibitors. Two patients discontinued from the study, one patient was removed due to lack of treatment satisfaction and one patient requested to withdraw but remained on rIX-FP prophylaxis. The interim data cut-off is due to occur later in 2020, and further data collected will be reported.

Conclusion Initial data from this study indicates that rIX-FP is well tolerated, with low bleed rates and few adverse events in both adults and paediatrics in routine clinical practice. Further data will be collected to assess the effectiveness and safety profile of rIX-FP in the real-world clinical setting.

Publication History

Article published online:
18 June 2021